Weeks Old (week + old)

Distribution by Scientific Domains
Distribution within Medical Sciences

Selected Abstracts

Influences of postconceptional age and postnatal experience on the development of auditory recognition memory in the newborn infant

Raye-Ann deRegnier
Abstract We evaluated the effects of postconceptional age and postnatal experience on the development of neonatal auditory recognition memory. Three groups were tested: a premature newborn group (tested at 35,38 weeks postconceptional age, ,1 week old), a full-term newborn group (tested at 39,42 weeks postconceptional age, ,1 week old), and a full-term experienced group (tested at 39,42 weeks postconceptional age, >1 week old; range 8,30 days). Event-related potentials were collected while infants listened to the maternal voice alternating with a stranger's voice. Postconceptional age was correlated with the development of recognition memory for the maternal voice while there were qualitative effects of postnatal experience on latency measurements. Maturity of auditory cortical responses was not correlated with recognition memory abilities. We conclude that maturation of the recognition memory pathways is primarily a function of postconceptional age with qualitative effects of postnatal experience. Maturation of the auditory recognition memory pathway is not contingent upon maturation of the "P2" peak thought to arise from primary auditory cortex. © 2002 Wiley Periodicals, Inc. Dev Psychobiol 41: 216,225, 2002. Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/dev.10070 [source]

Sod2 overexpression preserves myoblast mitochondrial mass and function, but not muscle mass with aging

AGING CELL, Issue 3 2009
Sukkyoo Lee
Summary Mice lacking superoxide dismutase-2 (SOD2 or MnSOD) die during embryonic or early neonatal development, with diffuse superoxide-induced mitochondrial damage. Although stem and progenitor cells are exquisitely sensitive to oxidant stress, they have not been well studied in MnSOD2-manipulated mouse models. Patterns of proliferation and differentiation of cultured myoblasts (muscle progenitor cells), PI3-Akt signaling during differentiation, and the maintenance of mitochondrial mass with aging using myoblasts from young (3,4 week old) and aged (27,29 months old) MnSOD2-overexpressing (Sod2- Tg) and heterozygote (Sod2+/,) mice were characterized by us. Overexpression of MnSOD2 in myoblasts had a protective effect on mitochondrial DNA abundance and some aspects of mitochondrial function with aging, and preservation of differentiation potential. Sod2 deficiency resulted in defective signaling in the PI3-Akt pathway, specifically impaired phosphorylation of Akt at Ser473 and Thr308 in young myoblasts, and decreased differentiation potential. Compared with young myoblasts, aged myoblast Akt was constitutively phosphorylated, unresponsive to mitogen signaling, and indifferent to MnSOD2 levels. These data suggest that specific sites in the PI3K-Akt pathway are more sensitive to increased superoxide levels than to the increased hydrogen peroxide levels generated in Sod2 -transgenic myoblasts. In wild-type myoblasts, aging was associated with significant loss of mitochondrial DNA relative to chromosomal DNA, but MnSOD2 overexpression was associated with maintained myoblast mitochondrial DNA with aging. [source]

Chemical mediation of reciprocal mother,offspring recognition in the Southern Water Skink (Eulamprus heatwolei)

Abstract Kin recognition has been demonstrated to play an important role in the social structure of a wide range of animals. Most studies to date have examined parent,offspring recognition only in species that provide offspring with direct parental care, however, there are several advantages to parent,offspring recognition even in the absence of direct parental care. In this study we investigated reciprocal mother,offspring recognition in the Australian scincid lizard Eulamprus heatwolei, a species that does not show direct parental care. We examined whether neonates could discriminate between their mothers and unrelated females, and whether females could discriminate between their offspring and unrelated neonates, via chemical cues, using retreat site selection experiments. We conducted trials when neonates were 1 and 4 weeks old to investigate whether responses are maintained as neonates age. We found that both neonates and mothers could discriminate between related and unrelated individuals when neonates were 1 week old. Mothers were more likely to take refuge under tiles treated with the odours of their own offspring, while neonates spent less time in areas treated with the odours of unrelated females. At 4 weeks of age, mothers no longer exhibited discriminatory behaviour between their offspring and unrelated neonates, while neonates were more likely to associate with the odour of any female over the odourless control. We hypothesize that reciprocal mother,offspring recognition in E. heatwolei reduces interference competition between mothers and their offspring and also may be important in habitat selection and territory establishment. [source]

Effects of early weaning on anxiety and prefrontal cortical and hippocampal myelination in male and female wistar rats

Yuka Kodama
Abstract We investigated developmental changes in myelin formation in the prefrontal cortex and the hippocampus, and behavioral effects of early weaning in Wistar rats. Early-weaned rats showed decreased numbers of open-arm entries in an elevated plus-maze in both sexes at 4 weeks old; this effect persisted in males, but ceased in females after this age. Expression of myelin basic protein (MBP) showed both age-dependent increases and sex differences; 4-week-old males exhibited higher MBP levels in the hippocampus, whereas 7-week-old males showed lower MBP levels in the prefrontal cortex compared to females of the same age. There was a tendency for group differences from weaning for the 21.5-kDa isoform in the prefrontal cortex. Although these results suggest that male rats are more vulnerable than females to early-weaning effects on anxiety-related behaviors, further detailed analysis is needed to clarify the functional relationship between myelination and anxiety-related behaviors. © 2008 Wiley Periodicals, Inc. Dev Psychobiol 50: 332,342, 2008. [source]

Enhanced Calcium Influx in Hippocampal CA3 Neurons of Spontaneously Epileptic Rats

EPILEPSIA, Issue 3 2001
Hiroko Amano
Summary: ,Purpose: The spontaneously epileptic rat (SER: tm/tm, zi/zi) shows both absence-like seizures and tonic convulsions. Our previous electrophysiologic studies have demonstrated that SER has abnormal excitability of hippocampal CA3 neurons, which shows a long-lasting depolarization shift by a single stimulation of mossy fibers, probably resulting from the Ca2+ channel abnormalities. The present study was performed to determine whether Ca2+ influx is actually enhanced in the CA3 area of SER. Methods: Hippocampal slices were prepared from normal Wistar rats and SER aged 11,16 weeks old, when the epileptic seizures had been observed, and loaded with fura-2AM. Intracellular Ca2+ concentration ([Ca2+]i) was monitored as the ratio of fluorescence intensities excited at wavelengths of 340 and 380 nm (RF340/F380) with photometric devices. Results: High K+ (10,60 mM) applied to the bath for 2 min increased [Ca2+]i in hippocampal CA1, CA3, and dentate gyrus (DG) areas of both the normal rats and SER in a concentration-dependent manner. However, the high K+,induced increase in [Ca2+]i was significantly more pronounced in the CA3 area of the SER than in that of the normal animals, whereas there were no significant differences in high K+,induced increases of [Ca2+]i in CA1 or DG between the SER and controls. The high K+,induced increases in [Ca2+]i of CA1, CA3, and DG were inhibited by nifedipine (1,10 nM), a Ca2+ channel antagonist in both SER and controls. However, the inhibition of the high K+,induced increase in [Ca2+]i by nifedipine (1 nM) was significantly greater in the CA3 area of SER than that of controls. Conclusions: These findings suggest that Ca2+ influx through the L-type Ca2+ channels is much greater in the CA3 area of SER than in that of normal animals and is involved in the epileptic seizures of the SER. [source]

Neonatal maternal separation and enhancement of the inspiratory (phrenic) response to hypoxia in adult rats: disruption of GABAergic neurotransmission in the nucleus tractus solitarius

Richard Kinkead
Abstract Neonatal maternal separation (NMS) alters respiratory control development. Adult male rats previously subjected to NMS show a hypoxic ventilatory response 25% greater than controls. During hypoxia, ,-aminobutyric acid (GABA) release within the nucleus tractus solitarius (NTS) modulates the magnitude of the ventilatory response. Because development of GABAergic receptors is sensitive to NMS, we tested the hypothesis that in adults, a change in responsiveness to GABA within the NTS contributes to NMS-related enhancement of the inspiratory (phrenic) response to hypoxia. Pups subjected to NMS were placed in an incubator for 3 h/day for 10 consecutive days [postnatal days 3 to 12]. Controls were undisturbed. Adult (8,10 weeks old) rats were anaesthetized (urethane; 1.6 g/kg), paralysed and artificially ventilated to record phrenic activity. Rats either received a 50-nL microinjection of GABA (5 µm) or phosphate-buffered saline (sham) within the caudal NTS, or no injection prior to being exposed to hypoxia (FiO2 = 0.12; 5 min). NMS enhanced both the frequency and amplitude components of the phrenic response to hypoxia vs controls. GABA microinjection attenuated the phrenic responses in NMS rats only. This result is supported by ligand binding autoradiography results showing that the number of GABAA receptors within the NTS was 69% greater in NMS vs controls. Despite this increase, the phrenic response to hypoxia of NMS rats is larger than controls, suggesting that the higher responsiveness to GABA microinjection within the NTS is part of a mechanism that aims to compensate for: (i) a deficient GABAergic modulation; (ii) enhancement of excitatory inputs converging onto this structure; or (iii) both. [source]

Chronic Hypoxia Delays Myocardial Lactate Dehydrogenase Maturation in Young Rats

Z. Daneshrad
The effect of exposure to hypobaric hypoxia for 4 weeks (oxygen pressure = 106 hPa), equivalent to 5500 m in altitude) on myocardial total lactate dehydrogenase (tLDH) activity and isoform (H and M) composition was comparatively studied in growing (4.5 weeks old) and in adult (4.5 months old) male rats. The consequences of the hypoxia-induced anorexia were checked in growing rats using a pair-fed group. Exposure to hypoxia induced a significant decrease in the H/tLDH ratio in the left (LV) and right ventricle (RV) of growing and adult rats. In adult rats this alteration was mainly a consequence of the significant increase in the specific activity of the M isomer, which resulted in an increase in the overall LDH activity. In contrast, in the LV of young rats exposed to hypoxia, the specific activity of the M isomer was similar to that of normoxic animals while the H isomer activity was significantly lower than in normoxic rats, and the overall LDH activity remained unchanged. These effects were specifically due to hypoxia per se since no significant alterations were observed in pair-fed animals. In the hypertrophied RV, the alteration of H and M isomers following hypoxia was similar to that observed in adults (i.e. no change in H and an increase in M isoform). We conclude that the well-known hypoxia-induced decrease in the H/tLDH ratio is governed by different age-dependent mechanisms. In adult rats, hypoxia may induce in both ventricles a stimulating effect on M isomer expression. In the LV of growing rats this stress could inhibit the H isomer maturation without any effect on the M isomer. In the RV of growing rats this effect could have been counteracted by the growth effect of the hypertrophying process. [source]

Age at Acquisition of Helicobacter pylori in a Pediatric Canadian First Nations Population

HELICOBACTER, Issue 2 2002
Samir K. Sinha
Abstract Background. Few data exist regarding the epidem-iology of Helicobacter pylori infections in aboriginal, including the First Nations (Indian) or Inuit (Eskimo) populations of North America. We have previously found 95% of the adults in Wasagamack, a First Nations community in Northeastern Manitoba, Canada, are seropositive for H. pylori. We aimed to determine the age at acquisition of H. pylori among the children of this community, and if any association existed with stool occult blood or demographic factors. Materials and Methods. We prospectively enrolled children resident in the Wasagamack First Nation in August 1999. A demographic questionnaire was administered. Stool was collected, frozen and batch analyzed by enzyme-linked immunosorbent assay (ELISA) for H. pylori antigen and for the presence of occult blood. Questionnaire data were analyzed and correlated with the presence or absence of H. pylori. Results. 163 (47%) of the estimated 350 children aged 6 weeks to 12 years, resident in the community were enrolled. Stool was positive for H. pylori in 92 (56%). By the second year of life 67% were positive for H. pylori. The youngest to test positive was 6 weeks old. There was no correlation of a positive H. pylori status with gender, presence of pets, serum Hgb, or stool occult blood. Forty-three percent of H. pylori positive and 24% of H. pylori negative children were < 50th percentile for height (p = 0.024). Positive H. pylori status was associated with the use of indoor pail toileting (86/143) compared with outhouse toileting (6/20) (p = 0.01). Conclusions. In a community with widespread H. pylori infection, overcrowded housing and primitive toileting, H. pylori is acquired as early as 6 weeks of age, and by the second year of life 67% of children test positive for H. pylori. [source]

Prenatal stress modifies hippocampal synaptic plasticity and spatial learning in young rat offspring

HIPPOCAMPUS, Issue 5 2006
Jianli Yang
Abstract Clinical studies demonstrate that prenatal stress causes cognitive deficits and increases vulnerability to affective disorders in children and adolescents. The underlying mechanisms are not yet fully understood. Here, we reported that prenatal stress (10 unpredictable, 1 s, 0.8 mA foot shocks per day during gestational days 13,19) impaired long-term potentiation (LTP) but facilitated long-term depression (LTD) in hippocampal CA1 region in slices of the prenatal stressed offspring (5 weeks old). Cross-fostering neonate offspring by the prenatal stressed or control mothers did not change the effects of prenatal stress on the hippocampal LTP and LTD. Furthermore, prenatal stress enhanced the effects of acute stress on the hippocampal LTP and LTD and impaired spatial learning and memory in the Morris water maze in the young rat offspring. Therefore, prenatal stress alters synaptic plasticity and enhances the effects of acute stress on synaptic plasticity in the hippocampus, which may be the mechanism for the impaired spatial learning and memory in young rat offspring. © 2006 Wiley-Liss, Inc. [source]

Breeding success in a Houbara Bustard Chlamydotis [undulata] macqueenii population on the eastern fringe of the Jungar Basin, People's Republic of China

IBIS, Issue 2 2002
O. Combreau
Nesting success and chick survival of a migratory population of Houbara Bustard Chlamydotis [undulata] macqueenii were studied during three consecutive years (1998,2000) in the Xinjiang province of north-west China. A total of 45 nests was monitored and 85 broods comprising 227 chicks were captured, of which 82 chicks were radio-tracked. Start of laying varied between 6 and 17 April between years but the laying mode fell consistently between 26 and 30 April. Mean clutch size was 4.0 (sd = 0.8) (range 2,6) for early clutches and 3.3 (sd = 1.1) for late clutches (range 2,5). The average nesting success was 0.588 (sd = 0.270) but great variations were observed between years ,0.882 in 1998, 0.530 in 1999 and 0.351 in 2000. This was related to increased predation in 1999 and 2000, which is reflected by increased predator density (chiefly Corsac Fox Vulpes corsac and Long-legged Buzzards Buteo rufinus). The overall hatchability, defined as the proportion of eggs hatched in successful nests was 0.839 sd = 0.238). The average brood size at hatching varied from 2.9 (sd = 0.8) to 3.3 (sd = 0.9) according to years, and no significant decrease in brood size was observed in the first 5 days post-hatching. In 1999 and 2000 the brood size diminished sharply (14% and 27%, respectively) in prefledging chicks. A further severe decrease (37%) was observed in fledglings in 2000, probably due to predation by raptors. For the 3 years of the study, a successful female Houbara would bring on average 2.3 (sd = 0.9) chicks to fledging and would have lost 30.2% (sd = 14.9%) of its brood to adversity during the rearing process. The proportion of females that lost their entire brood was 0.181 in 1998, 0.708 in 1999 and 0.453 in 2000. For the 3 years of the study, only 55.3% (sd = 26.3%) of the females hatching eggs brought chicks to fledging. The overall chick production was 0.827 per breeding female per year and the probability of an egg laid producing a fledgling of 8 weeks old was 0.190. [source]

Transplanted XY germ cells produce spermatozoa in testes of XXY mice,

Y. Lue
Summary XXY mouse has been characterized as an experimental model for men with Klinefelter's syndrome (XXY male phenotype). To test whether donor XY germ cells could proliferate and differentiate in the XXY testicular environment, donor testicular cells from adult (2,3 months old) and immature (10 days old) XY green fluorescence protein (GFP) transgenic mice were transplanted into the seminiferous tubules of adult (4,7 months old) and young (6 weeks old) XXY recipient mice respectively. Twelve weeks after transplantation, GFP positive spermatogonia were found in 21.74% (five out of 23) of adult XXY recipients who received adult donor cells. The GFP positive segments of seminiferous tubules were observed in 44.44% (four out of nine) young XXY recipients who received donor cells from 10 days old GFP mice. We found using immunohistochemistry and cell morphology that donor-derived GFP positive germ cells were spermatogonia, spermatocytes, round spermatids and spermatozoa in some of the seminiferous tubules of young XXY recipient mice. The results demonstrated that the donor XY germ cells were able to qualitatively complete spermatogenesis in some of the seminiferous tubules of XXY mice. [source]

Determination of the selenium requirement in kittens,

K. J. Wedekind
Summary The purpose of this study was to determine the selenium (Se) requirement in kittens. Thirty-six specific-pathogen-free kittens (9.8 weeks old) were utilized in a randomized complete block design to determine the Se requirement in cats with gender and weight used as blocking criteria. Kittens were fed a low Se (0.02 mg/kg Se) torula yeast-based diet for 5 weeks (pre-test) after which an amino acid-based diet (0.027 mg Se/kg diet) was fed for 8 weeks (experimental period). Six levels of Se (0, 0.05, 0.075, 0.10, 0.20 and 0.30 mg Se/kg diet) as Na2SeO3 were added to the diet and were used to construct a response curve. Response variables included Se concentrations and Se-dependent glutathione peroxidase activities (GSHpx) in plasma and red blood cells (RBC) as well as plasma total T3 (TT3) and total T4 (TT4). No significant changes in food intake, weight gain or clinical signs of Se deficiency were noted. Estimates of the kitten's Se requirement (i.e. breakpoints) were determined for RBC and plasma GSHpx (0.12 and 0.15 mg Se/kg diet, respectively), but no definitive breakpoint was determined for plasma Se. Plasma TT3 increased linearly, whereas plasma TT4 and the ratio of TT4 : TT3 decreased in a quadratic fashion to dietary Se concentration. The requirement estimate determined in this study (0.15 mg Se/kg) for kittens is in close agreement with other species. As pet foods for cats contain a high proportion of animal protein with a Se bioavailability of 30%, it is recommended that commercial diets for cats contain 0.5 mg Se/kg DM. [source]

Untersuchungen zum Einfluß einer Xylanaseergänzung in Legehennenrationen auf Weizenbasis 2.

Mitteilung: Auswirkungen auf die Leistungsparameter
Summary The influence of a xylanase supplement on performance of laying hens fed different energy-graded, wheat-based rations was tested in a 12-week trial. Two varieties of wheat with different extraction viscosity were selected. In addition to the control ration, three test rations with reduced energy contents of ,3, ,6, and ,9% were used. Sixteen groups, each consisting of 30 hens were kept in single cages. At the beginning of the experiment hens were 24 weeks old. Single eggmass and daily eggmass production showed a statistically significant difference. This was not caused by the enzyme supplement or the energy content, but by the variety of wheat. Interaction effects between variety of wheat, enzyme supplement and energy content became obvious with regard to the yolk colour. The influence of the enzyme on the yolk colour is positive and statistically highly significant. Thus, the addition of xylanase to wheat-based rations does not affect the performance parameters of laying hens positively. Zusammenfassung In einem zwölfwöchigem Leistungsversuch wurde der Einfluß einer Xylanaseergänzung in Legehennenrationen auf Weizenbasis mit abgestuftem Energiegehalt auf die Leistungsparameter untersucht. Dazu wurden zwei Weizensorten (Alidos + Caprimus) mit unterschiedlicher Extraktviskosität ausgesucht und neben den jeweiligen Kontrollrationen drei Versuchsrationen mit abgestuftem Energiegehalt (,3%, ,6%, ,9%) eingesetzt. Den 16 Versuchsgruppen waren jeweils 30 Legehennen zugeordnet, die bei Versuchsbeginn 24 Lebenswochen alt waren. Es handelte sich um eine Einzelkäfigaufstallung. Statistisch signifikante Unterschiede ergaben sich bei der Einzeleimasse und der täglichen Eimasseproduktion, die sich jedoch weder dem Enzymzusatz noch dem Energiegehalt zuordnen ließen, sondern durch die Weizensorte bedingt waren. Es zeigten sich Wechselwirkungen zwischen Weizensorte, Enzymsupplementierung und Energiegehalt auf die Dotterfarbe. Es war ein statistisch hochsignifikanter positiver Enzymeinfluß auf die Dotterfarbe zu erkennen. Insgesamt gesehen, zeigte sich auch in diesem Legehennenversuch keine positive Wirkung der Xylanaseergänzung auf die Leistungsparamter zu Rationen auf Weizenbasis. [source]

Characterization of the nuclear matrix proteins in a transgenic mouse model for prostate cancer

Eddy S. Leman
Abstract The nuclear matrix (NM) contains a number of proteins that have been found to be associated with transformation. We have previously identified changes in the NM associated with prostate cancer. In this study, we examine the molecular changes that are associated with prostate cancer development in transgenic adenocarcinoma of mouse prostate (TRAMP) model by studying the differences in the NM proteins (NMPs). We collected prostates from the TRAMP males at six critical time points: 6 weeks (puberty), 11 and 19 weeks (development of mild hyperplasia), 25 weeks (development of severe hyperplasia), 31 and 37 weeks (development of neoplasia). The nuclear matrices from the prostates collected at these time points were then isolated and the NMPs were characterized by high-resolution two-dimensional gel electrophoresis. We found three NMPs (E1A, E1B, and E1C) that were present in the 6-week-old prostate and two NMPs (E2A and E2B) that were present in the 11-week-old prostate. These NMPs were absent in the 31- and 37-week-old prostate. We also found five NMPs (E3A,E3E) that were present in the 31-week-old prostate, but absent in the earlier time points. In addition, three NMPs (Le1, Le2, Le3) were present at higher expression in the 6-, 11-, 19-, and 25-weeks old TRAMP prostates, but they were expressed lower during the development of neoplasia at 31- and 37-weeks old. Identification of these NMPs permits the development of novel markers that can characterize various stages of prostate cancer development as well as potentially therapeutic targets. J. Cell. Biochem. 86: 203,212, 2002. © 2002 Wiley-Liss, Inc. [source]

Protected raspberry production accelerates onset of oviposition by vine weevils (Otiorhynchus sulcatus)

Scott N. Johnson
1Soft fruit production is increasingly reliant on crops that are grown under the protection of plastic tunnels, which may also affect insect communities as a result of localized climate change and changes to host plant physiology and chemistry. In particular, insect development rates may differ from field populations, making it more difficult to target control measures. 2The present study investigated how protected environments affected adult vine weevil (Otiorhynchus sulcatus) feeding and reproduction on red raspberry (Rubus idaeus). We focused on the period between adult emergence and the onset of oviposition (i.e. the pre-reproductive period), which represents the optimal period for control. 3Tunnels were up to 4 °C warmer than field plantations in 2008, with plants growing significantly faster (50% increase in height and 16% increase in leaf area) than field grown plants. The carbon/nitrogen ratio in leaves was higher in tunnels (12.07) than the field (10.89) as a result of a significant decrease in nitrogen concentrations (3.40 and 3.90 mg g,1, respectively). 4Over 4 weeks, weevils consumed significantly more foliage in tunnels (370.89 mg) than weevils in the field (166.68 mg), suggesting compensatory feeding to counteract lower leaf nitrogen concentrations. Weevils in tunnels achieved sexual maturity 8 days earlier than those in the field and produced 20-fold more eggs by the time they were 5 weeks old. 5Applying a degree-day model showed good agreement between predicted and observed pre-reproductive periods for weevils in tunnels (36 and 30 days, respectively) and in field plots (41 and 38 days, respectively). [source]

HEPATOLOGY: Electromagnetic thermoablation to treat thrombocytopenia in cirrhotic and hypersplenic rats

Roberto Zuchini
Abstract Background and Aim:, Thrombocytopenia due to hypersplenism is usually a serious condition in cirrhotic patients who have undergone invasive procedures. We designed a new treatment method using a high-frequency alternating electromagnetic force to treat the disease condition in a rat model. Methods:, Sprague,Dawley rats were given thioacetamide in drinking water and injected with methylcellulose intraperitoneally to create a cirrhotic hypersplenism model. Spleen volume was determined using the Carlson method. The Control Group consisted of 14 rats, 15 weeks old, that were used to determine the normal platelet count and normal spleen size. Experimental Group I, consisting of 15 rats, received electromagnetic thermoablation of their spleens, after which the spleen was returned to the abdomen. Group II consisted of 13 rats, receiving the same electromagnetic thermoablation as Group I, but the ablated portion was removed. Group III consisted of 14 rats receiving total splenectomies. Results:, Cirrhotic hypersplenism was confirmed during laparotomy and pathological examination. Spleen volume enlarged from 1513 ± 375 mm3 (Control Group) to 7943 ± 2822 mm3 (experimental groups). Platelet counts increased from 0.35 ± 0.21 × 106/mm3 to 0.87 ± 0.24 × 106/mm3 for Group I, from 0.52 ± 0.23 × 106/mm3 to 1.10 ± 0.20 × 106/mm3 for Group II, and from 0.47 ± 0.23 × 106/mm3 to 1.18 ± 0.26 × 106/mm3 for Group III. No rats died due to the treatment in any of the experimental groups. Conclusions:, Our animal model performed successfully and our proposed electromagnetic thermotherapy effectively treated thrombocytopenia due to cirrhotic hypersplenism. [source]

Ferucarbotran expands area treated by radiofrequency ablation in rabbit livers

Tatsuya Miyake
Abstract Background and Aim:, Several studies have examined the factors involved with expansion of the coagulation volume following radiofrequency ablation (RFA). Ferucarbotran contains superparamagnetic iron oxide that generates heat in a radiofrequency electric field and may have an effect on the area affected by RFA. We attempted to determine whether ferucarbotran administration expands radiofrequency-ablated volume using a rabbit model. Methods:, A total of 15 male Japanese white rabbits (16 weeks old) were used and divided into three groups of five each. A 1-mL saline solution was given intravenously into a dorsal ear vein in the control group, whereas 1 mL ferucarbotran solution (0.016 mL/kg bodyweight) was given to the common-dose group and 1 mL of a twofold concentrated ferucarbotran solution (0.032 mL/kg bodyweight) was given to the high-dose group. RFA was performed with a cool-tip electrode 4 h after the administration and immediately thereafter the rabbits were killed, and the volume of the ablated area measured using magnetic resonance imaging (MRI). Following the MRI analysis, the rabbit's livers were resected, and the maximum short axis diameter of the ablated area in each was measured. Results:, None of the rabbits died during the RFA procedure. The volume of the ablated area estimated on MR images in the ferucarbotran-administered groups was larger than that in the control group. Further, our macroscopic assessment showed that the maximum short axis diameter had a tendency to increase with ferucarbotran administration. Conclusion:, Ferucarbotran may expand the area treated by RFA. [source]

Immunohistochemical and electron microscopic study of invasion and differentiation in spinal cord lesion of neural stem cells grafted through cerebrospinal fluid in rat

Sufan Wu
Abstract Neurospheres were obtained by culturing hippocampal cells from transgenic rat fetuses (E16) expressing green fluorescent protein (GFP). The neurosphere cells were injected into the cerebrospinal fluid (CSF) through the 4th ventricle of young rats (4 weeks old) that had been given a contusion injury at T8,9 of the spinal cord. The injected neural stem cells were transported through the CSF to the spinal cord, attached to the pial surface at the lesion, and invaded extensively into the spinal cord tissue as well as into the nerve roots. The grafted stem cells survived well in the host spinal cord for as long as 8 months after transplantation. Immunohistochemical study showed that many grafted stem cells had differentiated into astrocytes at 1,4 months, and some into oligodendrocytes at 8 months postoperatively. Immunoelectron microscopy showed that the grafted stem cells were well integrated into the host tissue, extending their processes around nerve fibers in the same manner as astrocytes. In addition, grafted stem cells within nerve roots closely surrounded myelinated fibers or were integrated into unmyelinated fiber bundles; those associated with myelinated fibers formed basal laminae on their free surface, whereas those associated with unmyelinated fibers were directly attached to axons and Schwann cells, indicating that grafted stem cells behaved like Schwann cells in the nerve roots. © 2002 Wiley-Liss, Inc. [source]

Age and ovariectomy impair both the normalization of mechanical properties and the accretion of mineral by the fracture callus in rats

Ralph A. Meyer Jr.
The impact of age and ovariectomy on the healing of femoral fractures was studied in three groups of female rats at 8, 32 and 50 weeks of age at fracture. In the two older groups, the rats had been subjected to ovariectomy or sham surgery at random at 26 weeks of age. At fracture, all rats received unilateral intramedullary pinning of one femur and a middiaphyseal fracture. Rigidity and breaking load of the femora were evaluated at varying times up to 24 weeks after fracture induction by three-point bending to failure. Bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry. In the youngest group, 8-week-old female rats regained normal femoral rigidity and breaking load by 4 weeks after fracture. They exceeded normal contralateral values by 8 weeks after fracture. In the middle group, at 32 weeks of age, fractures were induced, and the femora were harvested at 6 and 12 weeks after fracture. At 6 weeks after fracture there was partial restoration of rigidity and breaking load. At 12 weeks after fracture, only the sham-operated rats had regained normal biomechanical values in their fractured femora, while the fractured femora of the ovariectomized rats remained significantly lower in both rigidity and breaking load. In contrast, for the oldest group of rats, 50 weeks old at fracture, neither sham-operated nor ovariectomized rats regained normal rigidity or breaking load in their fractured femora within the 24 weeks in which they were studied. In all fractured bones, there was a significant increase in BMD over the contralateral intact femora due to the increased bone tissue and bone mineral in the fracture callus. Ovariectomy significantly reduced the BMD of the intact femora and also reduced the gain in BMD by the fractured femora. In conclusion, age and ovariectomy significantly impair the process of fracture healing in female rats as judged by measurements of rigidity and breaking load in three-point bending and by accretion of mineral into the fracture callus. © 2001 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved. [source]

Protective effect of a marine oligopeptide preparation from Chum Salmon (Oncorhynchus keta) on radiation-induced immune suppression in mice

Ruiyue Yang
Abstract BACKGROUND: A marine oligopeptide preparation (MOP) obtained from Chum Salmon (Oncorhynchus keta) by the method of enzymatic hydrolysis, has been found to enhance the innate and adaptive immunities through stimulation of the secretion of cytokines in mice. The current study aimed to further investigate the protective effect of MOP on radiation-induced immune suppression in mice. RESULTS: Female ICR mice (6,8 weeks old) were randomly divided into three groups, i.e. blank control, irradiation control and MOP (1.350 g kg,1 body weight) plus irradiation-treated group. MOP significantly increased the survival rate and prolonged the survival times for 30 days after irradiation, and lessened the radiation-induced suppression of T- or B-lymphocyte proliferation, resulting in the recovery of cell-mediated and humoral immune functions. This effect may be produced by augmentation of the relative numbers of radioresistant CD4+ T cells, enhancement of the level of immunostimulatory cytokine, IL-12, reduction of the level of total cellular NF-,B through the induction of I,B in spleen and inhibition of the apoptosis of splenocytes. CONCLUSION: We propose that MOP be used as an ideal adjuvant therapy to alleviate radiation-induced injuries in cancer patients. Copyright © 2010 Society of Chemical Industry [source]

Eastern Equine Encephalitis in 9 South American Camelids

Rose Nolen-Walston
Background: Eastern equine encephalitis (EEE) virus is a mosquito-borne togavirus (alphavirus) that causes severe (often fatal) encephalitis in many mammalian species, but it has not been reported previously in South American camelids. Hypothesis: South American camelids can become naturally infected with EEE virus and show encephalitic signs similar to those observed in other affected species. Animals: Nine cases (8 alpacas and 1 llama, aged 3.5 weeks to 12 years) were identified; 4 of 9 were ,10 weeks old. All cases were from the East Coast of the United States and presented in late summer and fall. Methods: A retrospective study was performed to include confirmed cases of EEE in camelids in North America before 2006. Results: Eight of nine (89%) camelids died or were euthanized in extremis, with the mean time to death of 2 days. Clinical signs were consistent with encephalitis and included fever, lethargy, ataxia, seizures, recumbency, torticollis, opisthotonus, and vestibular signs. No consistent hematologic abnormalities were identified, and cerebrospinal fluid contained an increased protein concentration in the single camelid analyzed. No successful therapy was identified. EEE was confirmed by alphavirus detection by using immunohistochemistry (IHC) and polymerase chain reaction (PCR) in the central nervous system (CNS) and by serology. Findings included polioencephalitis with lymphocytic perivascular cuffing; neutrophil infiltration; gliosis; neuron satellitosis; necrosis; and edema, with intracytoplasmic alphavirus within neurons and glial cells. No virus was detected in extraneural tissues. Conclusions and Clinical Importance: In endemic areas, EEE should be considered a differential diagnosis for young and adult camelids with CNS disease. Brain histopathology with indirect IHC or PCR is diagnostic. [source]

Comparison of effects of in vivo nitrogen dioxide exposure starting from different periods on alveolar macrophage activity, assessed by a chemiluminescence technique in Brown-Norway rats

Takashi Kumae
Abstract Nitrogen dioxide (NO2) has been extensively studied for its immune modulating effects on pulmonary cells. Alveolar macrophages (AMs) play an important role in pulmonary immunity. The Brown-Norway (BN) rat has been studied as a high-risk model of allergic diseases. In this study, BN rats were exposed to NO2 from the embryonic or weanling period (EP or WP, respectively). To evaluate the effects of NO2 exposure on pulmonary immunity, the activity levels of rat AMs were assessed as reactive oxygen species-generating capacity, measured by a chemiluminescence (CL) technique, and as cytokine-producing ability. Except for 0.2 ppm of NO2 exposure, the CL responses of AMs obtained from the WP group at 12 weeks old were suppressed significantly. Changes of the cytokine-producing levels suggest that inflammatory reactions are terminated at 12 weeks in the EP group. Correlations between the CL responses and the cytokine levels reveal that NO2 exposure may modulate the direction of AM activation. The CL technique is thought to be useful to evaluate changes in AM activity. In this study, the results suggest that, using the high-risk model of allergic diseases, NO2 exposure from the weanling period has stronger effects on AM activity.Copyright © 2006 John Wiley & Sons, Ltd. [source]

Weight and weight gain at 4 months (The Netherlands 1998): influences of nutritional practices, socio-economic and ethnic factors

Anneke M. W. Bulk-Bunschoten
Summary We describe the determinants of weight gain in the first 4 months of life in a cohort of 3256 infants. The study was designed as a survey with follow-up. In the period 1 April to 1 July 1998, all infants, usually 4 weeks old but not older than 4 months, brought to a well-baby clinic for the first time were included. Nutritional practices, demographic data on mother and child, birthweight and a second weight measured between days 118 and 147 were recorded. Simple and multiple linear regression analyses were performed. The average weight gain over 4 months was 27.7 g/day for boys and 24.5 g/day for girls. Weight gain was lower with high parity and if the mother was a native Dutch speaker. Nutritional practices affected weight gain only slightly: exclusive breast feeding for 4 months lowered the weight gain by 0.06 g/day. However, because of their higher birthweight, breast-fed infants weighed a little more than formula-fed infants at 4 months. In addition, we compared the median weight at the age of 4 months with the median weight at the same age in previous Dutch growth studies. The median weight, adjusted to day 133, was higher in 1998 than in 1965, 1980 and 1997 (boys 7.15 vs. 6.85, 6.77 and 6.95 kg; girls 6.59 vs. 6.49, 6.39 and 6.45 kg respectively). [source]

A focal lesion in the falx cerebri: Harbinger of classic stage 4 neuroblastoma in an infant cured despite residual disease after minimal therapy

Brian H. Kushner MD
Abstract An asymptomatic 11 weeks old received no treatment after he was classified as having a suspected atypical form of MYCN -nonamplified hyperdiploid stage 4S neuroblastoma (NB), with masses in an adrenal gland, subcutaneous tissues, and the falx cerebri. Within 2 months, however, disease progressed in dura and bone marrow. Two cycles of low-dose chemotherapy achieved a partial response; treatment was discontinued. Complete remission was documented 24 weeks post-cycle 2, and has continued >6 years. The falx cerebri probably does not represent an atypical site for stage 4S NB, but stage 4 NB with favorable biology is sometimes curable with minimal therapy. Pediatr Blood Cancer 2009; 53:1340,1342. © 2009 Wiley-Liss, Inc. [source]

Prediction for developmental delay on Neonatal Oral Motor Assessment Scale in preterm infants without brain lesion

Sen-Wei Tsai
Abstract Background:, Preterm infants often have difficulty in achieving a coordinated sucking pattern. To analyze the correlation between preterm infants with disorganized sucking and future development, weekly studies were performed of 27 preterm infants from initiation of bottle feeding until a normal sucking pattern was recognized. Methods:, A total of 27 preterm infants without brain lesion participated in the present study. Neonatal Oral Motor Assessment Scale (NOMAS) was utilized to evaluate the sucking pattern. Infants who were initially assessed as having disorganized sucking on NOMAS and regained a normal sucking pattern by 37 weeks old were assigned to group I; infants with a persistent disorganized sucking pattern after 37 weeks were assigned to group II. The mental (MDI) and psychomotor (PDI) developmental indices of Bayley Scales of Infant Development, second edition were used for follow-up tests to demonstrate neurodevelopment at 6 months and 12 months of corrected age. Results:, At 6 months follow up, subjects in group I had a significantly higher PDI score than group II infants (P= 0.04). At 12 months follow up, group I subjects had a significantly higher score on MDI (P= 0.03) and PDI (P= 0.04). There was also a higher rate for development delay in group II at 6 months (P= 0.05). Conclusion:, NOMAS-based assessment for neonatal feeding performance could be a helpful tool to predict neurodevelopmental outcome at 6 and 12 months. Close follow up and early intervention may be necessary for infants who present with a disorganized sucking pattern after 37 weeks post-conceptional age. [source]

Attachment style and coping resources as predictors of coping strategies in the transition to parenthood

The relations among adult attachment style, coping resources, appraised strain, and coping strategies were examined in a prospective study of married couples having their first child (N= 92). Attachment and coping resources were measured during the second trimester of pregnancy, and parenting strain and coping strategies were assessed when the babies were about 6 weeks old. Results supported a theoretical model proposing that attachment is predictive of coping resources and appraised strain, and that attachment, resources, and strain are predictive of coping strategies. Results also highlighted the complexity of associations among attachment, stress, and coping: Gender differences in mean scores and predictive associations were obtained, and some interactions were found between resources and strain in predicting coping strategies. The findings support the utility of integrating theories of attachment and coping in explaining couples'adjustment to important developmental transitions. [source]

Cyclosporin-A suppresses p53-dependent repair DNA synthesis and apoptosis following ultraviolet-B irradiation

N. Sugie
Background: The combination of cyclosporin-A (CS-A) and ultraviolet-B (UV-B) irradiation is not recommended in the treatment of psoriasis, because risks of UV-B-induced skin cancer are increased. The recommendation, however, has not well been confirmed by basic researches. Purpose: In this study, we investigated the effects of CS-A on UV-B-induced repair DNA synthesis, apoptosis and p53 expression. Methods: Following the short-term administration of CS-A (5 and 50 mg/kg/day) or vehicle (V) alone, female BALB/c mice, 8,10 weeks old, were treated with UV-B irradiation (100 and 500 mJ2 cm) or tape stripping (TS). After the treatment, the effects of CS-A on the increased rate of epidermal DNA synthesis were examined by using 5,-bromodeoxyuridine (BrdU) pulse-labelling techniques. In separate experiments, the effects of CS-A on the number of sunburn cells, nick-end labelling + cells and p53 + cells were examined 24 h after UV-B irradiation. Results: Cyclosporin-A significantly suppressed the UV-B-induced increase in BrdU uptake, which occurs to repair DNA damage, while there were no significant effects on the stripping (S)-induced increase or the rate of normal epidermal proliferation, which is not associated with any DNA injuries. The number of sunburn cells, nick-end labelling + cells and p53 + cells was significantly reduced by pretreatment with CS-A. Conclusion: Cyclosporin-A interferes with the self- protective mechanisms involved in both repair and apoptotic removal of UV-B-induced DNA damage. The loss of p53 expression is responsible for the effects of CS-A. [source]

Modulatory influence of Andrographis paniculata on mouse hepatic and extrahepatic carcinogen metabolizing enzymes and antioxidant status

Rana P. Singh
Abstract The effects of two doses (50 and 100,mg/kg body wt/day for 14 days) of an 80% hydroalcohol extract of Andrographis paniculata and butylated hydroxyanisole (BHA) were examined on drug metabolizing enzymes, antioxidant enzymes, glutathione content, lactate dehydrogenase (LDH) and lipid peroxidation in the liver of Swiss albino mice (6,8 weeks old). The effect of the extract and BHA were also examined on lung, kidney and forestomach for the activities of glutathione S-transferase (GST), DT-diaphorase (DTD), superoxide dismutase (SOD) and catalase. A significant increase in the levels of acid soluble sulphydryl (-SH) content, cytochrome P450, cytochrome P450 reductase, cytochrome b5 reductase, GST, DTD and SOD were observed at both dose levels of extract treatment while catalase, glutathione peroxidase and glutathione reductase (GR) showed significant increases only at the higher dose in the liver. Both Andrographis treated groups showed a significant decrease in activity of LDH and malondialdehyde (MDA) formation. BHA treated mice showed a significant increase in the levels of cytochrome b5, GST, DTD, -SH content, GR and catalase in liver; while LDH and MDA levels were reduced significantly compared with their control values. In the lung, SOD, catalase and DTD, in the kidney catalase, DTD and GST, and in the forestomach SOD and DTD showed a significant increase at both dose levels of treatment. In BHA treated mice GST, DTD and catalase were significantly induced in the lung and along with these enzymes SOD was also induced in the kidney. In the case of the forestomach of BHA treated mice GST, DTD and SOD were enhanced significantly. These findings indicate the chemopreventive potential of Andrographis paniculata against chemotoxicity including carcinogenicity. Copyright © 2001 John Wiley & Sons, Ltd. [source]

The interactions of tooth colored dental restorative materials with aqueous lactic acid

Dr Sevil, ahmal
Abstract In this study, the interaction of packable composite and ormocer with aqueous lactic acid solutions were determined and changes compared with those for a polyacid modified resin composite and a glass ionomer. For each material, namely Solitaire, Z-100, Definite, Dyract AP and Vitremer, eight cylindrical specimens of 6,mm diameter and 12,mm height were prepared and weighed. They were stored individually in 20,cm3 0.02 mol,1 lactic acid solution for 1 week, then the pH was determined and the specimens reweighed. This was repeated at 1 week intervals until the specimens were 6 weeks old. The results of this study showed that; polyacid modified resin composites and resin-modified glass-ionomers were capable of increasing the pH of lactic acid solutions. The same groups showed an increase in mass during the first week. Composite resins and ormocer showed less increase in mass than the others. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Morphological changes induced in the pig kidney by extracorporeal shock wave lithotripsy: Nephron injury

Youzhi Shao
Abstract While shock wave lithotripsy (SWL) is known to cause significant damage to the kidney, little is known about the initial injury to cells along the nephron. In this study, one kidney in each of six juvenile pigs (6,7 weeks old) was treated with 1,000 shock waves (at 24 kV) directed at a lower pole calyx with an unmodified HM-3 lithotripter. Three pigs were utilized as sham-controls. Kidneys were fixed by vascular perfusion immediately after SWL or sham-SWL. Three of the treated kidneys were used to quantitate lesion size. Cortical and medullary samples for light (LM) and transmission electron microscopy (TEM) were taken from the focal zone for the shock waves (F2), the contralateral kidney, and the kidneys of sham-SWL pigs. Because preservation of the tissue occurred within minutes of SWL, the initial injury caused by the shock waves could be separated from secondary changes. No tissue damage was observed in contralateral sham-SWL kidneys, but treated kidneys showed signs of injury, with a lesion of 0.2% ± 0.1% of renal volume. Intraparenchymal hemorrhage and injury to tubules was found at F2 in both the cortex and medulla of SWL-treated kidneys. Tubular injury was always associated with intraparenchymal bleeding, and the range of tissue injury included total destruction of tubules, focal cellular fragmentation, necrosis, cell vacuolization, and membrane blebbing. The initial injury caused by SWL was cellular fragmentation and necrosis. Cellular vacuolization, membrane blebbing, and disorganization of apical brush borders appear to be secondary changes related to hypoxia. Anat Rec Part A 275A:979,989, 2003. © 2003 Wiley-Liss, Inc. [source]