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Distribution by Scientific Domains

Medical Sciences	47%
Life Sciences	31%
Chemistry	10%

Selected Abstracts

Storage-associated artefact in equine muscle biopsy samples

EQUINE VETERINARY JOURNAL, Issue 1 2009
R. L. Stanley
Summary Reasons for performing study: Muscle biopsy is increasingly used in equine veterinary practice for investigating exertional, inflammatory or immune mediated myopathies and unexplained muscle atrophy. Although formalin-fixed samples are often used, for complete evaluation, fresh-frozen tissue is required. Freezing muscle in veterinary practice is impractical: samples sent to specialist laboratories for processing are therefore susceptible to delays, potentially leading to artefact and compromising histological interpretation. Hypothesis: Altered temperature, duration and hydration status influence the severity of storage-induced artefact in equine muscle. Methods: Skeletal muscle obtained immediately post euthanasia was divided into 6 independent samples from each of 8 horses. One sample per horse was frozen immediately in isopentane precooled in liquid nitrogen. Additional samples were stored in conditions designed to mimic possible situations encountered in practice, including increased storage times, temperature and hydration status. Following storage, stored samples were frozen as before. Cryosections were stained using haematoxylin and eosin and ranked for artefact on 2 occasions by 2 blinded observers. The best samples were processed subsequently with a panel of routine stains and immunolabelled for collagen V to enable the measurement of minimum fibre diameters. Results: Both prolonged storage and increased hydration resulted in more storage-associated artefact. Samples stored for 24 h chilled on dry gauze were ranked higher than those stored on damp gauze; however, a panel of routinely-used histochemical staining techniques was unaffected by chilled 24 h storage. There was no significant effect of storage on mean fibre diameter; however, both chilled dry and damp storage for 24 h caused a significant increase in fibre-size variability. Conclusion and potential relevance: Caution should be exercised when interpreting fibre size profiles in shipped samples. Equine muscle biopsy samples are optimally shipped in dry gauze, sealed in plastic containers and shipped on ice packs to be processed within 24 h and can thus be interpreted by the receiving laboratory with minimal artefact. [source]

The petrous bone,A new sampling site for identifying early dietary patterns in stable isotopic studies

AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 2 2009
Marie Louise S. Jørkov
Abstract Intraskeletal variation in the composition of carbon (,13C) and nitrogen (,15N) stable isotopes measured in collagen is tested from various human bones and dentine. Samples were taken from the femur, rib, and petrous part of the temporal bone from well-preserved skeletons of both adults (n = 34) and subadults (n = 24). Additional samples of dentine from the root of 1st molars were taken from 16 individuals. The skeletal material is from a medieval cemetery (AD 1200,1573) in Holbæk, Denmark. Our results indicate that the petrous bone has an isotopic signal that differs significantly from that of femur and rib within the single skeleton (P < 0.001 and P < 0.001, respectively), with only minor variation seen between femur and rib. On the other hand, there was no significant difference between the petrous bone and the 1st molar. The intraskeletal variation may reflect differences in turnover rate among skeletal elements. The inner periosteal layer of the petrous bone is formed in uterus and does not undergo any further remodelling after the age of 2 years, whereas the rib and femur have a continuous turnover rate of ,5 and 10,20 years, respectively. From the results of this study it is believed the petrous bone may be a new useful bone element and a supplement or a proxy for teeth in the analysis of early dietary patterns as it may reflect diet in fetal stages and early years of life. Am J Phys Anthropol 2009. © 2008 Wiley-Liss, Inc. [source]

Mechanical injury potentiates proteoglycan catabolism induced by interleukin-6 with soluble interleukin-6 receptor and tumor necrosis factor , in immature bovine and adult human articular cartilage

ARTHRITIS & RHEUMATISM, Issue 10 2009
Yihong Sui
Objective Traumatic joint injury can damage cartilage and release inflammatory cytokines from adjacent joint tissue. The present study was undertaken to study the combined effects of compression injury, tumor necrosis factor , (TNF,), and interleukin-6 (IL-6) and its soluble receptor (sIL-6R) on immature bovine and adult human knee and ankle cartilage, using an in vitro model, and to test the hypothesis that endogenous IL-6 plays a role in proteoglycan loss caused by a combination of injury and TNF,. Methods Injured or uninjured cartilage disks were incubated with or without TNF, and/or IL-6/sIL-6R. Additional samples were preincubated with an IL-6,blocking antibody Fab fragment and subjected to injury and TNF, treatment. Treatment effects were assessed by histologic analysis, measurement of glycosaminoglycan (GAG) loss, Western blot to determine proteoglycan degradation, zymography, radiolabeling to determine chondrocyte biosynthesis, and Western blot and enzyme-linked immunosorbent assay to determine chondrocyte production of IL-6. Results In bovine cartilage samples, injury combined with TNF, and IL-6/sIL-6R exposure caused the most severe GAG loss. Findings in human knee and ankle cartilage were strikingly similar to those in bovine samples, although in human ankle tissue, the GAG loss was less severe than that observed in human knee tissue. Without exogenous IL-6/sIL-6R, injury plus TNF, exposure up-regulated chondrocyte production of IL-6, but incubation with the IL-6,blocking Fab significantly reduced proteoglycan degradation. Conclusion Our findings indicate that mechanical injury potentiates the catabolic effects of TNF, and IL-6/sIL-6R in causing proteoglycan degradation in human and bovine cartilage. The temporal and spatial evolution of degradation suggests the importance of transport of biomolecules, which may be altered by overload injury. The catabolic effects of injury plus TNF, appeared partly due to endogenous IL-6, since GAG loss was partially abrogated by an IL-6,blocking Fab. [source]

Premature cessation of breastfeeding in infants: development and evaluation of a predictive model in two Argentinian cohorts: the CLACYD study,, 1993,1999

ACTA PAEDIATRICA, Issue 5 2001
S Berra
The objective of this study was to develop a model to predict premature cessation of breastfeeding of newborns, in order to detect at-risk groups that would benefit from special assistance programmes. The model was constructed using 700 children with a birthweight of 2000 g or more, in 2 representative cohorts in 1993 and 1995 (CLACYD I sample) in Córdoba, Argentina. Data were analysed from 632 of the cases. Mothers were selected during hospital admittance for childbirth and interviewed in their homes at 1 mo and 6 mo. To evaluate the model, an additional sample with similar characteristics was drawn during 1998 (CLACYD II sample). A questionnaire was administered to 347 mothers during the first 24,48 h after birth and a follow-up was completed at 6 mo, with weaning information on 291 cases. Premature cessation of breastfeeding was considered when it occurred prior to 6 mo. A logistic regression model was fitted to predict premature end of breastfeeding, and was applied to the CLACYD II sample. The calibration (Hosmer-Lemeshow C statistic) and the discrimination [area under the receiver operating characteristics (ROC) curve] of the model were evaluated. The predictive factors of premature end of breastfeeding were: mother breastfed for less than 6 mo [odds ratio (OR) = 1.84,95% confidence interval (CI) 1.26,2.70], breastfeeding of previous child for less than 6 mo (OR = 4.01, 95% CI 2.58,6.20), the condition of the firstborn child (OR = 2.75, 95% CI 1.79,4.21), the first mother-child contact occurring after 90min of life (OR =1.88; 95% CI 1.22,2.91) and having an unplanned pregnancy (OR = 1.50, 95% CI 1.05,2.15). The calibration of the model was acceptable in the CLACYD I sample (p= 0.54), as well as in the CLACYD II sample (p= 0.18). The areas under the ROC curve were 0.72 and 0.68, respectively. Conclusion: A model has been suggested that provides some insight onto background factors for the premature end of breastfeeding. Although some limitations prevent its general use at a population level, it may be a useful tool in the identification of women with a high probability of early weaning. [source]

Avoiding the effect of item wording by means of bipolar instead of unipolar items: An application to social optimism

EUROPEAN JOURNAL OF PERSONALITY, Issue 2 2010
Karl Schweizer
Abstract Scales including positively and negatively worded items usually show an impaired degree of homogeneity. The transformation of unipolar positively and negatively worded items into bipolar items can avoid this disadvantageous effect. The precondition for this transformation is that each pair of items refers to the same topic. It is this topic that serves as the heading of the bipolar item. This scale construction method is demonstrated in the items of the social optimism scale (Schweizer & Schneider, 1997) that comprises unipolar items. The investigation of both the original and the transformed scales in a sample of 808 participants revealed equivalence and a high quality for both scales. Results of an additional sample confirmed the validity of both social optimism scales. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Sexual or clonal origin?

FEDDES REPERTORIUM, Issue 3-4 2005
A morpho-ecological, molecular analysis in a patch of Ajuga reptans L. (Lamiaceae)
Spatial clonal structure and patch colonisation in Ajuga reptans L. (Lamiaceae), a common stoloniferous semi-rosette plant, were studied using a combined morpho-ecological and molecular genetic approach. Within a natural patch from a forest near Diedorf (Thuringia, Germany), the spatial clonal structure was analysed, correlating both datasets: Morphologically, characteristics of clonal growth and clonal reproduction were studied, the spatial distribution of modules was mapped and merigenet relationships were reconstructed. Samples from the patch and its surroundings, and an additional sample from Berlin were then analysed by AFLP fingerprinting using four different primer combinations to identify genets. Most divergence in banding patterns was already obtained for samples from the Diedorf forest. Within the patch, however, most samples had very similar fingerprints, indicating their belonging to the same genet and hence a clonal origin, although they are morphologically separated into three "plants". Based on AFLP data, the relationships of one sample remained ambiguous; but the correlation with morphological data helped to interpret the pattern and indicated that the sample is probably a dividual of the clone, too. The relevance of the observed vegetative multiplication (clonal growth and subsequent clonal reproduction) for patch colonisation and maintenance are discussed. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) Generativer (sexueller) oder klonaler Ursprung? Eine morpho-ökologische und molekulare Analyse in einem ,patch' von Ajuga reptans L. (Lamiaceae) Die räumliche klonale Struktur und die ,patch' Besiedlung von Ajuga reptans L. (Lamiaceae), einer häufigen Halbrosettenpflanze mit Ausläufern, wurden mit einem morpho-ökologischen und molekular-genetischen Ansatz kombiniert analysiert. Die Untersuchung wurde in einem ,patch' aus einem Wald bei Diedorf (Thüringen) durchgeführt: Morphologisch wurden Merkmale des klonalen Wachstums und der klonalen Reproduktion untersucht, die räumliche Verteilung der Module kartiert und Merigenet-Beziehungen rekonstruiert. Für Proben aus dem ,patch', aus dessen näherer Umgebung und einer Pflanze aus Berlin wurden AFLP Analysen mit vier verschiedenen Primer-Kombinationen durchgeführt, um genetische Individuen (Genets) zu identifizieren. Die meisten Unterschiede in den Fragmentmustern zeigten sich bereits zwischen Proben aus Diedorf. Die ,patch'-Proben (morphologisch aufgeteilt in drei "Pflanzen") hatten jedoch sehr ähnliche fingerprints, was ihre Zugehörigkeit zum selben Genet und eine klonale Abstammung belegt. Für eine Probe ließen sich die Verwandtschaftsbeziehungen mit den AFLP Daten nicht sicher klären. Der Abgleich mit den morphologischen Ergebnissen ermöglichte jedoch eine Interpretation, und deutet auf die Zugehörigkeit zum Klon. Die Bedeutung der "vegetativen Multiplikation" (durch klonales Wachstum und klonale Reproduktion) für die Besiedlung und dauerhafte Besetzung von ,patches' wird diskutiert. [source]

Novel mutations in the MYOC/GLC1A gene in a large group of glaucoma patients,,

HUMAN MUTATION, Issue 6 2002
Karin Michels-Rautenstrauss
Abstract Mutations at the myocilin (MYOC) gene within the GLC1A locus have been revealed in 2-4% of patients suffering primary open angle glaucoma (POAG) worldwide. In our ongoing glaucoma study sixhundred eighty two persons have been screend for MYOC mutations. The first group consisted of 453 patients from a long-term clinical study diagnosed either with juvenile OAG (JOAG), POAG, ocular hypertension (OHT) or normal tension glaucoma (NTG) plus 22 cases of secondary glaucoma. This group, and additional 83 healthy controls, is part of a long term study with repeated clinical examinations at the University of Erlangen-Nurnberg. An additional sample of 124 glaucoma patients or at risk persons referred from other sources were included in the mutation screening. Five novel mutations, namely Gly434Ser, Asn450Asp, Val251Ala, Ile345Met and Ser393Asn, could be identified as cause of preperimetric POAG, JOAG, normal tension POAG and POAG. Myocilin mutations were identified similar with previous reports with other ethnic populations at the rate of 11/341 (3.2%) probands. © 2002 Wiley-Liss, Inc. [source]

Ficus racemosa is pollinated by a single population of a single agaonid wasp species in continental South-East Asia

MOLECULAR ECOLOGY, Issue 13 2010
N. KOBMOO
Abstract High specificity in the Ficus -agaonid wasp mutualism has lead to the assumption of a mostly ,one-to-one' relationship, albeit with some exceptions. This view has been challenged by new molecular data in recent years, but surprisingly little is known about local and spatial genetic structuring of agaonid wasp populations. Using microsatellite markers, we analysed genetic structuring of Ceratosolen fusciceps, the fig wasp pollinating Ficus racemosa, a fig tree species widely distributed from India to Australia. In sampling stretching from the south of China to the south of Thailand we found evidence for only a single pollinating wasp species in continental South-East Asian mainland. We found no evidence for the co-occurrence of cryptic species within our subcontinent sampling zone. We observed no spatial genetic structure within sites and only limited structuring over the whole sampling zone, suggesting that F. racemosa is pollinated by a single population of a single agaonid wasp species all over continental South-East Asia. An additional sample of wasps collected on F. racemosa in Australia showed clear-cut genetic differentiation from the Asian continent, suggesting allopatric divergence into subspecies or species. We propose that the frequent local co-occurrence of sister species found in the literature mainly stems from contact zones between biogeographic regions, and that a single pollinator species over wide areas might be the more common situation everywhere else. [source]

Desorption electrospray ionization mass spectrometric analysis of organophosphorus chemical warfare agents using ion mobility and tandem mass spectrometry

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 11 2010
Paul A. D'Agostino
Desorption electrospray ionization mass spectrometry (DESI-MS) has been applied to the direct analysis of sample media for target chemicals, including chemical warfare agents (CWA), without the need for additional sample handling. During the present study, solid-phase microextraction (SPME) fibers were used to sample the headspace above five organophosphorus CWA, O -isopropyl methylphosphonofluoridate (sarin, GB), O -pinacolyl methylphosphonofluoridate (soman, GD), O -ethyl N,N -dimethyl phosphoramidocyanidate (tabun, GA), O -cyclohexyl methylphosphonofluoridate (cyclohexyl sarin, GF) and O -ethyl S-2-diisopropylaminoethyl methyl phosphonothiolate (VX) spiked into glass headspace sampling vials. Following sampling, the SPME fibers were introduced directly into a modified ESI source, enabling rapid and safe DESI of the toxic compounds. A SYNAPT HDMSÔ instrument was used to acquire time-aligned parallel (TAP) fragmentation data, which provided both ion mobility and MSn (n,=,2 or 3) data useful for the confirmation of CWA. Unique ion mobility profiles were acquired for each compound and characteristic product ions of the ion mobility separated ions were produced in the TriwaveÔ transfer collision region. Up to six full scanning MSn spectra, containing the [M,+,H]+ ion and up to seven diagnostic product ions, were acquired for each CWA during SPME fiber analysis. A rapid screening approach, based on the developed methodology, was applied to several typical forensic media, including Dacron sampling swabs spiked with 5,µg of CWA. Background interference was minimal and the spiked CWA were readily identified within one minute on the basis of the acquired ion mobility and mass spectrometric data. Copyright © 2010 Crown in the right of Canada. Published by John Wiley & Sons, Ltd. [source]

On a Supplemented Case,Control Design

BIOMETRICS, Issue 2 2005
Ruth M. Pfeiffer
Summary The supplemented case,control design consists of a case,control sample and of an additional sample of disease-free subjects who arise from a given stratum of one of the measured exposures in the case,control study. The supplemental data might, for example, arise from a population survey conducted independently of the case,control study. This design improves precision of estimates of main effects and especially of joint exposures, particularly when joint exposures are uncommon and the prevalence of one of the exposures is low. We first present a pseudo-likelihood estimator (PLE) that is easy to compute. We further adapt two-phase design methods to find maximum likelihood estimates (MLEs) for the log odds ratios for this design and derive asymptotic variance estimators that appropriately account for the differences in sampling schemes of this design from that of the traditional two-phase design. As an illustration of our design we present a study that was conducted to assess the influence to joint exposure of hepatitis-B virus (HBV) and hepatitis-C virus (HCV) infection on the risk of hepatocellular carcinoma in data from Qidong County, Jiangsu Province, China. [source]

A limited sampling strategy for tacrolimus in renal transplant patients

BRITISH JOURNAL OF CLINICAL PHARMACOLOGY, Issue 4 2008
Binu S. Mathew
WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT , Tacrolimus trough concentration is being currently used for dose individualization. , Limited sampling strategies (LSS) have been developed and validated for renal transplant patients. , Earlier literature has suggested that measurement of tacrolimus AUC is more reliable than trough with respect to both rejection and nephrotoxicity. WHAT THIS STUDY ADDS , Four thousand renal transplants take place annually in India, with many patients prescribed tacrolimus in combination with mycophenolate and steroid. , In this study a LSS with two points, i.e. trough and 1.5 h postdose was developed and validated to estimate AUC0,12. , The added benefit of only a single additional sample with completion of blood collection in 1.5 h and minimum additional cost makes this a viable LSS algorithm in renal transplant patients. , In patients having tacrolimus trough concentrations outside the recommended range (<3 and >10 ng ml,1 in the treatment protocol in our institution) or having side-effects in spite of trough concentrations in the desired range, we can estimate AUC using this LSS for a better prediction of exposure. AIMS To develop and validate limited sampling strategy (LSS) equations to estimate area under the curve (AUC0,12) in renal transplant patients. METHODS Twenty-nine renal transplant patients (3,6 months post transplant) who were at steady state with respect to tacrolimus kinetics were included in this study. The blood samples starting with the predose (trough) and collected at fixed time points for 12 h were analysed by microparticle enzyme immunoassay. Linear regression analysis estimated the correlations of tacrolimus concentrations at different sampling time points with the total measured AUC0,12. By applying multiple stepwise linear regression analysis, LSS equations with acceptable correlation coefficients (R2), bias and precision were identified. The predictive performance of these models was validated by the jackknife technique. RESULTS Three models were identified, all with R2 , 0.907. Two point models included one with trough (C0) and 1.5 h postdose (C1.5), another with trough and 4 h postdose. Increasing the number of sampling time points to more than two increased R2 marginally (0.951 to 0.990). After jackknife validation, the two sampling time point (trough and 1.5 h postdose) model accurately predicted AUC0,12. Regression coefficient R2 = 0.951, intraclass correlation = 0.976, bias [95% confidence interval (CI)] 0.53% (,2.63, 3.69) and precision (95% CI) 6.35% (4.36, 8.35). CONCLUSION The two-point LSS equation [AUC0,12 = 19.16 + (6.75.C0) + (3.33.C1.5)] can be used as a predictable and accurate measure of AUC0,12 in stable renal transplant patients prescribed prednisolone and mycophenolate. [source]

The significance of the number of submitted samples and patient-related factors for faecal bacterial diagnostics

CLINICAL MICROBIOLOGY AND INFECTION, Issue 11 2007
S. Ethelberg
Abstract The sensitivity of bacteriological testing of faecal samples from patients with diarrhoea has not been properly determined. The present study analysed the association between the results of stool sample examinations and the number of samples examined per patient and other patient-related factors. Data concerning faecal specimens referred for culture for enteric bacterial pathogens (Campylobacter, Salmonella, Shigella and Yersinia) to the central microbiological laboratory in Denmark between 1995 and 2003 were analysed. In total, 620 000 samples were sorted into 277 000 sample-series, i.e., samples submitted from the same individual on the same day. Data were analysed by multivariate logistic regression, with the outcome being a positive sample-series, i.e., one or more positive samples per series. Overall, 11.9% of the sample-series were positive. For adults (aged ,18 years), the OR for a positive diagnosis was 1.20 (95% CI 1.18,1.21) for each additional sample. Positive diagnoses were also more likely during summer, if the patient was male, or if the patient was neither very young nor very old. The added diagnostic effect of additional samples was more pronounced for the group of patients with persistent (>2 weeks) diarrhoea. Overall, the probability of finding common pathogenic bacteria in faecal samples was found to vary according to the number of samples, the season and the patient's age and gender. Analysis of more than one sample improves the sensitivity of faecal culture by at least 20% for each additional sample. [source]

Improvements for comparative analysis of changes in diversity of microbial communities using internal standards in PCR-DGGE

FEMS MICROBIOLOGY ECOLOGY, Issue 3 2005
Dorthe Groth Petersen
Abstract The use of internal standards both during DNA extraction and PCR-DGGE procedure gives the opportunity to analyse the relative abundance of individual species back to the original sample, thereby facilitating relative comparative analysis of diversity. Internal standards were used throughout the DNA extraction and PCR-DGGE to compensate for experimental variability. Such variability causes decreased reproducibility among replicate samples as well as compromise comparisons between samples, since experimental errors cannot be differentiated from actual changes in the community abundance and structure. The use of internal standards during DNA extraction and PCR-DGGE is suitable for ecological and ecotoxicological experiments with microbial communities, where relative changes in the community abundance and structure are studied. We have developed a protocol Internal Standards in Molecular Analysis of Diversity (ISMAD) that is simple to use, inexpensive, rapid to perform and it does not require additional samples to be processed. The internal standard for DNA extraction (ExtrIS) is a fluorescent 510-basepair PCR product which is added to the samples prior to DNA extraction, recovered together with the extracted DNA from the samples and analysed with fluorescence spectrophotometry. The use of ExtrIS during isolation of sample DNA significantly reduced variation among replicate samples. The PCR internal standard (PCRIS) originates from the Drosophila melanogaster genome and is a 140-basepair long PCR product, which is amplified by non-competitive primers in the same PCR reaction tubes as the target DNA and analysed together with the target PCR product on the same DGGE gel. The use of PCRIS during PCR significantly reduced variation among replicate samples both when assessing total PCR product and when comparing bands representing species on a DGGE gel. The entire ISMAD protocol was shown to accurately describe changes in relative abundance in an environmental sample using PCR-DGGE. It should, however, be mentioned that despite the use of ISMAD some inherent biases still exist in DNA extraction and PCR-DGGE and these should be taken into consideration when interpreting the diversity in a sample based on a DGGE gel. [source]

Mixing immiscible blends in an intermeshing counter-rotating twin screw extruder

ADVANCES IN POLYMER TECHNOLOGY, Issue 2 2006
Ramesh Potluri
Abstract Domain size of 10% dispersed polystyrene in polyethylene was followed in a 34-mm intermeshing counter-rotating twin screw extruder. Variables studied included the effects of barrel temperature, screw speed, viscosity ratio of dispersed-to-continuous phase, and parallel melt versus preblended solids feeds. After steady state was achieved, die samples were quenched for later photomicrographing. The extruder was then stopped and quenched, with subsequent pulling of the screws. From 7 to 12 additional samples were taken along the 18/1 L/D extruder for determination of the mechanism of dispersion and dispersed phase domain size by optical microscopy. At low temperatures, the polystyrene tended to fracture with sharp edges. The fine particles formed in the initial breakup underwent no further size reduction. At higher temperatures, fractured segments had rounder edges, but the size of the small domains remained constant throughout the axial length. There was some evidence of flocculation and coalescence prior to exit through the die. © 2006 Wiley Periodicals, Inc. Adv Polym Techn 25: 81,89, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20065 [source]

Influence of sexual stimulation on sperm parameters in semen samples collected via masturbation from normozoospermic men or cryptozoospermic men participating in an assisted reproduction programme

ANDROLOGIA, Issue 3 2000
Y. Yamamoto
Summary. To evaluate the influence of sexual stimulation via sexually stimulating videotaped visual images (VIM) on sperm function, two semen samples were collected from each of 19 normozoospermic men via masturbation with VIM. Two additional samples were collected from each man via masturbation without VIM. The volume of seminal plasma, total sperm count, sperm motility, percentage of morphologically normal spermatozoa, outcome of hypo-osmotic swelling test and zona-free hamster oocyte sperm penetration assay, and markers of the secretory function of prostate were significantly larger in semen samples collected via masturbation with VIM than masturbation without VIM. The improved sperm parameters in the samples collected via masturbation with VIM may reflect an enhanced prostatic secretory function and increased loading of the vas deferens at that time. In a similar protocol, two semen samples were collected via masturbation with VIM from each of 22 non-obstructed azoospermic men. Semen samples from these men had been occasionally positive in the past for a very small number of spermatozoa (cryptozoospermic men). Two additional samples were collected from each cryptozoospermic man via masturbation without VIM. The volume of seminal plasma, total sperm count, sperm motility, and a marker of the secretory function of prostate were significantly larger in semen samples collected via masturbation with VIM. Fourteen out of the 22 men were negative for spermatozoa in both samples collected via masturbation without VIM. These men demonstrated spermatozoa in both samples collected via masturbation with VIM. Six men with immotile spermatozoa in both samples collected via masturbation without VIM exposed motile spermatozoa in both samples collected via masturbation with VIM. High sexual stimulation during masturbation with VIM results in recovery of spermatozoa of greater fertilizing potential both in normozoospermic and cryptozoospermic men. The appearance of spermatozoa after masturbation with VIM in the vast majority of cryptozoospermic men is of clinical significance in programmes applying intracytoplasmic sperm injections for the management of severe male infertility and obviates the need for testicular biopsy. [source]

Optimal Two-Stage Design for Case-Control Association Analysis Incorporating Genotyping Errors

ANNALS OF HUMAN GENETICS, Issue 3 2008
Y. Zuo
Summary Two-stage design is a cost effective approach for identifying disease genes in genetic studies and it has received much attention recently. In general, there are two types of two-stage designs that differ on the methods and samples used to measure allele frequencies in the first stage: (1) Individual genotyping is used in the first stage; (2) DNA pooling is used in the first stage. In this paper, we focus on the latter. Zuo et al. (2006) investigated statistical power of such a design, among other things, but the cost of the study was not taken into account. The purpose of this paper is to study the optimal design under the given overall cost. We investigate how to allocate the resources to the two stages. Note that in addition to the measurement errors associated with DNA pooling, genotyping errors are also unavoidable with individual genotyping. Therefore, we discuss the optimal design combining genotyping errors associated with individual genotyping. The joint statistical distributions of test statistics in the first and second stages are derived. For a fixed cost, our results show that the optimal design requires no additional samples in the second stage but only that the samples in the first stage be re-used. When the second stage uses an entirely independent sample, however, the optimal design under a given cost depends on the population allele frequency and allele frequency difference between the case and control groups. For the current genotyping costs, we can roughly allocate 1/3 to 1/2 of the total sample size to the first stage for screening. [source]

Determining the success of vasectomy

BJU INTERNATIONAL, Issue 4 2006
NIVEDITA BHATTA DHAR
OBJECTIVES To examine patient compliance, significance of rare nonmotile sperm (RNMS) and to determine the timing and number of semen analyses required to confirm sterility. PATIENTS AND METHODS From November 2001 to November 2004, 436 consecutive primary vasectomies were performed by one surgeon. All patients were instructed to submit two initial semen specimens for analysis (2 and 3 months after vasectomy) and additional samples (at 1-month intervals) if sperm were identified on the initial and subsequent analyses. RESULTS A quarter of the patients submitted no semen specimens and only 21% followed the full instructions to provide two consecutive negative semen analyses. Three-quarters of the patients provided a semen specimen at 8 weeks after vasectomy; of these, 75% were azoospermic and 25% contained sperm. At 12 weeks after vasectomy half the patients provided a semen specimen; of these, 91% were azoospermic and 9% contained sperm. Of the 83 patients with semen containing sperm at 8 weeks, 80 had RNMS and three had rare motile sperm (one of whom subsequently proved to have vasectomy failure). Of the 80 patients with RNMS, at 3, 4, 5, 6, 8, 10 and 11 months, 65, four, three, four, two, one and one, respectively were azoospermic. CONCLUSIONS The present results indicate that many patients are not compliant with the protocol after vasectomy. Provided patients have been adequately counselled, we think that one negative semen analysis at 3 months or one with RNMS at 2 months may be adequate to determine the success of vasectomy. This should reduce the number of semen analyses, including reducing the number of men who must undergo repeat testing, without sacrificing the accuracy of determining paternity. Simplifying the follow-up after vasectomy is important; not only would it be cost-effective but it may also improve patient compliance. [source]

Tuberculosis (TB) and HIV infection are independently associated with elevated serum concentrations of tumour necrosis factor receptor type 1 and ,2 -microglobulin, respectively

CLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 1 2000
S. D. Lawn
The aim of this study was to identify immune markers that are independently associated with HIV infection or TB in vivo. Using commercially available assays, we measured concentrations of five immune markers in sera from 175 out-patients attending medical clinics in Cote D'Ivoire and Ghana, West Africa. Patients were categorized into groups with TB only (TB+HIV,, n = 55), TB and HIV co-infection (TB+HIV+, n = 50), HIV infection only (TB,HIV+, n = 35), or neither infection (TB,HIV,, n = 35). TB+HIV+ and TB,HIV+ groups were matched for blood CD4+ lymphocyte count. Mean ±,s.d. concentrations of ,2 -microglobulin were similarly increased in both the TB,HIV+ (5·3 ± 2·1 ,g/ml, P < 0·0001) and the TB+HIV+ (5·0 ± 1·5 ,g/ml, P < 0·0001) groups compared with the TB,HIV, group (2·2 ± 1·8 ,g/ml), but were only slightly increased in the TB+HIV, group (3·2 ± 1·8 ,g/ml, P = 0·01). In contrast, mean serum concentrations of soluble tumour necrosis factor receptor type I (sTNF-RI) were similarly elevated in the TB+HIV, (1873 ± 799 pg/ml, P < 0·0001) and TB+HIV+ (1797 ± 571 pg/ml, P < 0·0001) groups compared with uninfected subjects (906 ± 613 pg/ml), but there was only a small increase in sTNF-RI in the TB,HIV+ group (1231 ± 165 pg/ml, P = 0·03). Both TB and HIV infection were associated with substantial elevation of serum concentrations of soluble CD8, soluble CD54, and sTNF-R type II. Analysis of additional samples from groups of TB+HIV, and TB+HIV+ patients receiving anti-TB treatment showed significant and equal reductions in mean serum sTNF-RI concentrations, but no significant change in mean ,2 -microglobulin. Thus, serum ,2 -microglobulin and sTNF-RI serve as relatively independent markers of HIV infection and TB, respectively, in studies of co-infected persons. [source]