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Hind Legs (hind + leg)

Distribution by Scientific Domains

Medical Sciences	57%
Life Sciences	42%

Selected Abstracts

Recanalization of the Collecting Lymphatics in Rabbit Hind Leg

MICROCIRCULATION, Issue 5 2006
FUMITAKA IKOMI
ABSTRACT Objective: This study was designed to examine whether mature collecting lymphatics can regenerate in the adult tissue or not. Materials and Methods: The X-ray lymphograms were used to detect network of the collecting lymphatics in rabbit hind leg. Regeneration of the lymphatics was observed after surgical removal of the popliteal lymph node or a part of the popliteal afferent lymphatic. Structure and mechanical properties of the lymphatics were also examined by light and electron microscopes and in vitro functional experiments. Results: One week after removal of the lymph node, only an afferent lymphatic and a deposit of the contrast medium at the popliteal region were observed. Four weeks after the removal, the connection of the afferent and efferent lymphatics at the popliteal region, and collateral lymphatics were present in the leg. Further, 4 weeks after 1-mm excisions of a part of the lymphatic, recanalization was observed between the central and peripheral cut ends of the lymphatic but not after 3- and 10-mm excisions. Endothelial cells and smooth muscle cells could be observed by electron microscope, and contractile proteins, and alpha-smooth muscle actin SM1 and SM2 were immunofluorescently detected in both intact and the regenerated lymphatic walls. In both lymphatics, norepinephrine and acetylcholine induced dose-dependent constriction and dilation of the vessels, respectively. Conclusion: The present study demonstrated that mature collecting lymphatics are able to regenerate in the adult tissues. [source]

Long-term evolution of the acute tubular necrosis (ATN) induced by glycerol: role of myofibroblasts and macrophages

INTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 4 2002
Telma J. Soares
Summary. Late structural changes such as interstitial fibrosis in the renal cortex and tubular atrophy have been detected after severe acute tubular necrosis (ATN). The aim of this study was to investigate the expression of fibronectin, ,-smooth muscle actin and macrophages during the evolution of the ATN induced by glycerol and their relationship with the late structural changes observed in the kidneys of these animals. Forty-nine male Wistar rats were injected with a 50% glycerol solution, 8 mL/kg (4 mL/kg applied i.m. to each hind leg) and 14 with 0.15 m NaCl solution. Before glycerol injection on day 1, water was removed for 17 h. Blood and urine samples were collected 1 day after the injection to quantify sodium and creatinine. The animals were killed 5, 30 and 60 days after the injections and the kidneys removed for histological and immunohistochemical studies. The results of the histological and immunohistochemical studies were scored according to the extent of lesion or staining in the cortical tubulointerstitium, respectively. The percentage of tubulointerstitial lesions was determined by morphometry. Glycerol-injected rats presented a transitory increase in plasma creatinine levels and in fractional sodium excretion. The immunohistochemical studies showed increased fibronectin, ,-smooth muscle actin (,-SM-actin), TGF-, and ED-1 (macrophages) staining in the renal cortex from rats killed 5, 30 and 60 days after glycerol injection (P < 0.05) compared to control. The animals killed on day 30 and 60 also presented chronic lesions (fibrosis, tubular dilatation and atrophy) in the renal cortex, despite the recovery of renal function. Macrophages, TGF-, and myofibroblasts may have contributed to the development of renal fibrosis in these rats. [source]

Evaluation of nano-technology-modified zirconia oral implants: a study in rabbits

JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 7 2009
Jaebum Lee
Abstract Objective: The objective of this study was to screen candidate nano-technology-modified, micro-structured zirconia implant surfaces relative to local bone formation and osseointegration. Materials and Methods: Proprietary nano-technology surface-modified (calcium phosphate: CaP) micro-structured zirconia implants (A and C), control micro-structured zirconia implants (ZiUniteÔ), and titanium porous oxide implants (TiUniteÔ) were implanted into the femoral condyle in 40 adult male New Zealand White rabbits. Each animal received one implant in each hind leg; thus, 20 animals received A and C implants and 20 animals received ZiUniteÔ and TiUniteÔ implants in contralateral hind legs. Ten animals/group were euthanized at weeks 3 and 6 when biopsies of the implant sites were processed for histometric analysis using digital photomicrographs produced using backscatter scanning electron microscopy. Results: The TiUniteÔ surface demonstrated significantly greater bone,implant contact (BIC) (77.6±2.6%) compared with the A (64.6±3.6%) and C (62.2±3.1%) surfaces at 3 weeks (p<0.05). Numerical differences between ZiUniteÔ (70.5±3.1%) and A and C surfaces did not reach statistical significance (p>0.05). Similarly, there were non-significant differences between the TiUniteÔ and the ZiUniteÔ surfaces (p>0.05). At 6 weeks, there were no significant differences in BIC between the TiUniteÔ (67.1±4.2%), ZiUniteÔ (69.7±5.7%), A (68.6±1.9%), and C (64.5±4.1%) surfaces (p>0.05). Conclusion: TiUniteÔ and ZiUniteÔ implant surfaces exhibit high levels of osseointegration that, in this model, confirm their advanced osteoconductive properties. Addition of CaP nano-technology to the ZiUniteÔ surface does not enhance the already advanced osteoconductivity displayed by the TiUniteÔ and ZiUniteÔ implant surfaces. [source]

Inductively coupled helmholtz coil on a dedicated imaging platform for the in vivo1H-MRS measurement of intramyocellular lipids in the hind leg of rats

MAGNETIC RESONANCE IN MEDICINE, Issue 4 2009
Michael Neumaier PhD
Abstract Skeletal muscle triglycerides are markers for insulin resistance in type 2 diabetes. Recently, MR spectroscopy was adapted for in vivo measurement of triglycerides in animal models and for the characterization of new therapeutic approaches. Because of small MR spectroscopy voxel sizes used in skeletal muscles, surface coils are used for signal reception. Furthermore, to obtain well-resolved and undistorted lipid spectra, muscle fibers must be aligned parallel to the magnetic field. Consequently, to achieve a high signal-to-noise ratio and spectral quality, a coil setup must combine high sensitivity with a reliable and reproducible positioning of muscle and voxel. These demands are difficult to match using surface coils. Here, a coil platform is described, which uses inductively coupled Helmholtz coil setup combined with a leg retainer system for rats. The new system allows for measurement of intramyocellular lipids with high signal-to-noise ratio and for significantly improved animal handling, positioning, and throughput. Magn Reson Med, 2009. © 2009 Wiley-Liss, Inc. [source]

Recanalization of the Collecting Lymphatics in Rabbit Hind Leg

Actions of motor neurons and leg muscles in jumping by planthopper insects (hemiptera, issidae)

THE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 8 2010
Malcolm Burrows
Abstract To understand the catapult mechanism that propels jumping in a planthopper insect, the innervation and action of key muscles were analyzed. The large trochanteral depressor muscle, M133b,c, is innervated by two motor neurons and by two dorsal unpaired median (DUM) neurons, all with axons in N3C. A smaller depressor muscle, M133a, is innervated by two neurons, one with a large-diameter cell body, a large, blind-ending dendrite, and a giant ovoid, axon measuring 50 ,m by 30 ,m in nerve N5A. The trochanteral levator muscles (M132) and (M131) are innervated by N4 and N3B, respectively. The actions of these muscles in a restrained jump were divisible into a three-phase pattern. First, both hind legs were moved into a cocked position by high-frequency bursts of spikes in the levator muscles lasting about 0.5 seconds. Second, and once both legs were cocked, M133b,c received a long continuous sequence of motor spikes, but the two levators spiked only sporadically. The spikes in the two motor neurons to M133b,c on one side were closely coupled to each other and to the spikes on the other side. If one hind leg was cocked then the spikes only occurred in motor neurons to that side. The final phase was the jump movement itself, which occurred when the depressor spikes ceased and which lasted 1 ms. Muscles 133b,c activated synchronously on both sides, are responsible for generating the power, and M133a and its giant neuron may play a role in triggering the release of a jump. J. Comp. Neurol. 518:1349,1369, 2010. © 2009 Wiley-Liss, Inc. [source]

Photocrosslinkable Chitosan Hydrogel Can Prevent Bone Formation in Both Rat Skull and Fibula Bone Defects

ARTIFICIAL ORGANS, Issue 1 2009
Yoshifumi Tsuda
Abstract UV light irradiation to a photocrosslinkable chitosan (Az-CH-LA) resulted in an insoluble and flexible hydrogel within 30 s. The purpose of this study was to evaluate the ability of the photocrosslinkable chitosan to inhibit bone formation in the bone defects. A 5-mm-diameter defect was made in the rat calvarium, and then photocrosslinkable chitosan was implanted and irradiated with UV for 30 s. Furthermore, a 2-mm defect was made in the fibula of a rat hind leg, and then photocrosslinkable chitosan was implanted and irradiated with UV. Bone formations in the rat skull and fibula defects with photocrosslinkable chitosan hydrogel were significantly prevented for 8 weeks. Thus, the chitosan hydrogel has an inhibitory effect on bone formation. [source]

Evaluation of nano-technology-modified zirconia oral implants: a study in rabbits

Free radical scavengers are more effective than indomethacin in the prevention of experimentally induced heterotopic ossification

JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 2 2007
L.C. Vanden Bossche
Abstract The pathogenesis of heterotopic ossification is still unclear and the preventive therapies are usually insufficient. The present study was designed to investigate the possible preventive effect of free radical scavengers on the development of experimentally induced heterotopic ossification in a rabbit model and to compare free radical scavengers with indomethacin to determine whether they act synergistically. A standard immobilization,manipulation model was used to induce heterotopical ossification in the hind legs of 40 1-year-old female New Zealand albino rabbits. The animals were divided into four groups and received daily either placebo, a free radical scavenger cocktail [allopurinol and N -acetylcysteine (A/A)], indomethacin or the combination of A/A and indomethacin in a randomized double-blind fashion. Every 4 days an X-ray was taken and the thickness and length of new bone formation was measured at the thigh. A marked statistically significant difference was found between the four groups. In the groups that received A/A, either alone or combined with indomethacin, an inhibition of bone growth, both in thickness and in length was demonstrated. In this experimental model free radical scavengers had a superior inhibitory effect on heterotopic ossification than indomethacin. Free radicals could play an important role in the pathogenesis of heterotopic ossification. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:267,272, 2007 [source]

Is growth hormone a radioprotective agent?

JOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 3 2006
SB Tekin
Abstract There is currently substantial clinical interest in growth hormone (GH) as a protective agent against radiation-related normal tissue injury. To further assess the potential radiation injury-preventive effects of GH, these effects were studied in rats by using a radiation-induced skin injury model. Group 1 received neither GH nor irradiation (control group). Group 2 received 30 Gy of gamma irradiation as a single dose to the right hind legs of the rats (radiation group). Group 3 and 4 received the same irradiation plus either 0.01 U/kg/day GH (RT + 0.01 GH group) or 0.02 U/kg/day GH (RT + 0.02 GH group) subcutaneously. Clinically and histopathologically, acute skin reactions were assessed by two independent experts in radiation oncology and pathology, respectively. Irradiation increased dermatitis in rats when compared with the control group. The severity of radiodermatitis in the rats in the RT + 0.01 GH and RT + 0.02 GH groups was significantly lower than that in the RT group; radiodermatitis developed earlier in the RT group than in the other groups. GH was efficacious in preventing epidermal atrophy, dermal degeneration such as oedema and collagen fibre loss, and hair follicle atrophy, but not better than in the control group. These results are preliminary to studies that will be performed with higher doses of GH in radiation-treated cancer patients, with the aim of reducing radiation-induced toxicity. [source]

Fragrances, male display and mating behaviour of Euglossa hemichlora: a flight cage experiment

PHYSIOLOGICAL ENTOMOLOGY, Issue 4 2003
Thomas Eltz
Abstract., Male euglossine bees (Apidae: Euglossini) collect volatile substances (fragrances) from floral and nonfloral sources and store them in hair-filled cavities in their hind tibiae. Over time, males accumulate large quantities of complex and species-specific blends of fragrances. Various hypotheses have been put forward to explain this behaviour, including the idea that fragrance stores reflect the genetic quality of individual males and have evolved through sexual selection and female choice. Clear support of this hypothesis is lacking, largely because male,female interactions are both rare and difficult to observe in nature. Here, we report a flight cage experiment performed in Panama that permitted mating between virgin females (raised from brood cells) and males captured in the forest at fragrance baits. In the cage, eight individually marked males defended small territories around vertical perch sites and showed a characteristic display, which included a previously unreported ,leg-crossing' movement, possibly related to fragrance release. A total of six copulations and three copulatory attempts by Euglossa hemichlora were observed and partly recorded on video. The copulations, all of which were initiated by the female landing on a male perch, were short (4,10 s) and showed no signs of the transfer of chemical substances from male to female. In some cases, the male hovered directly over the female before descending to mount her, possibly facilitating fragrance evaluation by the female. After the experiment, the contents of the males' hind legs were analysed by gas chromatography-mass spectroscopy, which detected complex mixtures of terpenoids and aromatics (totalling 70 different compounds) dominated by hexahydrofarnesyl acetone, farnesene epoxide, ocimene and p -dimethoxy benzene. Individual total amounts of fragrances were neither related to display activity or perch occupancy by given males, nor to the frequency of matings achieved. Display activity was the only positive correlate of mating frequency. Generally, individuals had uniformly large amounts of stored fragrances in comparison to a previous study of three other species of Panamanian Euglossa. [source]

Actions of motor neurons and leg muscles in jumping by planthopper insects (hemiptera, issidae)

Morphology and physiology of vibratory interneurons in the thoracic ganglia of the southern green stinkbug Nezara viridula (L.)

THE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 2 2008
Maja Zorovi
Abstract The central processing mechanisms of vibratory signals in small plant-dwelling insects that rely primarily on substrate-borne vibratory communication are still largely unknown. To elucidate the neural mechanisms involved in vibratory signaling, the vibration-sensitive interneurons in thoracic ganglia of the southern green stinkbug, Nezara viridula, were investigated electrophysiologically by single-cell recordings and staining. Ten types of interneurons were described and divided into four categories, based on their gross morphology. The cell body of the L-shaped CG-AC neurons is located in the metathoracic neuromere of the central ganglion, and the axon ascends contralaterally. This group comprises five types of neurons differing in their fine structure and functional properties. CG-AB neurons are dorsal unpaired median (DUM) neurons with cell bodies in the mesothoracic neuromere of the central ganglion and two axons that ascend bilaterally into the prothoracic ganglion. Group CG-L includes three types of local neurons limited to the central ganglion. With ipsilateral dendritic arborizations and contralateral axonal branching, their gross morphology is similar to that of cricket omega cells. Interneuron PTG-DC, with the cell body in the prothoracic ganglion (PTG) and a contralaterally descending axon, conveys information received by the sensory organs of the front contralateral leg to the neuropil regions of the ipsilateral middle and hind legs. Based on their frequency tuning and acceleration sensitivity, the vibratory interneurons fall into two groups: the low-frequency units are tuned to 50 Hz and the middle frequency units to 200 Hz, with their acceleration thresholds at 10,1 m/s2 and 5 × 10,3 m/s2, respectively. Their function is discussed with relevance to the vibratory communication of N. viridula. J. Comp. Neurol. 508:365,381, 2008. © 2008 Wiley-Liss, Inc. [source]

Hybridization, developmental stability, and functionality of morphological traits in the ground beetle Carabus solieri (Coleoptera, Carabidae)

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2006
STEPHANE GARNIER
The assessment of developmental stability in hybrids can provide valuable information in the study of species formation because it allows an evaluation of the degree of incompatibility of genetic systems that control developmental processes. The present study assessed the impact of two hybridization events, assumed to have occurred at different times, on developmental instability in the ground beetle Carabus solieri. Developmental instability was estimated in 678 individuals from 27 populations from the fluctuating asymmetry (FA) levels of four morphological traits: the tibia length of middle and hind legs, which are functional structures, and the length and the proximal width of the hind wings, which are vestigial and thus nonfunctional structures. Significant variations of FA levels between populations were shown only for the wing width. For this trait, FA levels in hybrids were higher than in their parental entities for both hybridization events, indicating a significant divergence of the gene systems controlling development between the parental entities in the two hybridization cases. As expected, wing traits exhibited FA levels at least three times higher than leg trait. Finally, the potential interest of vestigial traits in the particular context of hybridization is discussed. © 2006 The Linnean Society of London, Biological Journal of the Linnean Society, 2006, 89, 151,158. [source]