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At least 847 records · Page 47Linked to original sources
PubMed1999

Pathophysiological and genetic characterization of the major diabetes locus in GK rats.

Genetic studies of the type 2 diabetes-like GK rat have revealed several susceptibility loci for the compound diabetes phenotype. Congenic strains were established for Niddm1, the major quantitative trait locus (QTL) for postprandial glucose levels, by transfer of GK alleles onto the genome of the normoglycemic F344 rat. Despite the polygenic nature of diabetes in GK, the locus-specific diabetes phenotype was retained in the congenic strain Niddmla, containing a GK-derived genomic fragment of 52 cM from the Niddm1 locus. Furthermore, Niddm1 was divided into two non-overlapping loci, physically separated in the two congenic strains Niddmlb and Niddm1i with distinct metabolic phenotypes. Both strains displayed postprandial hyperglycemia and reduced insulin action in isolated adipose cells. Furthermore, Niddm1i already exhibits a pronounced in vivo insulin secretion defect at 65 days, while Niddm1b develops a relative insulin secretory defect at 95 days. This suggests that Niddm1i impairs mechanisms common to insulin secretion in pancreatic B-cells and insulin action in adipocytes. Niddm1b rats show signs of increasing insulin resistance with age associated with obesity, hyperinsulinemia, and dyslipidemia. Moreover, the data indicated nonallelic interaction (epistasis) between Niddm1b and Niddm1i on the postprandial glucose levels. These data emphasize the pathophysiological complexity of diabetes, even within an apparently single QTL, and demonstrate the potential of the GK model in transforming the multifactorial diabetes phenotype into single traits, suitable for positional cloning.

Adipose Tissue↗
PubMed1996

Analysis of poultry fertility data. 3. Analysis of the duration of fertility in naturally mating Japanese quail.

The purpose of the present study was to test the appropriateness of iterative least squares regression for the evaluation of fertility data in naturally mating quail. In each of four trials, 20 male and 200 female randombred Japanese quail were housed in stacked breeder cages. Paired females were exposed to their assigned male for a single 48-h period. Eggs were collected for 2 wk following removal of the male, incubated, and fertility determined by visual inspection at egg breakout. In Trials 1 and 3, sexually experienced males were placed with experienced and inexperienced females, respectively. In Trials 2 and 4, inexperienced males were placed with experienced and inexperienced females, respectively. Duration of fertility, by male, was analyzed by iterative least squares, using the model y(x) = gamma/(1 + e beta(tau - x)). Overall fertility was analyzed with a log odds model following transformation to logits. Iterative least squares provided estimates of fertility duration of 3.75 to 9.18 d, with significant (P < 0.05) differences in the duration of fertility observed between individual males as well as between the trials. Differences (P < 0.05) in overall fertility (17.7 to 58.3%) were also observed, with inexperienced males paired with experienced females exhibiting the lowest overall means. Taken together, these results suggest that iterative least squares may be used to evaluate fertility in naturally mating populations and that reproductive experience can have a profound effect on the interpretation of fertility in naturally mating quail.

Animals↗
PubMed2002

Description of dental arch form using the Fourier series.

The aim of this study was to describe the form of the human superior dental arch using Fourier transformations. Forty models made in dental stone from impressions of the maxillary dental arch were used to obtain the reference data, which were expressed in Cartesian coordinates, from the mesovestibular cuspid vertices of molar teeth, vestibular cuspid of premolars, and incisal edge. Fourth-grade equations and Fourier series were calculated from these data. The results indicate that Fourier series more precisely express the form and size of different dental arches, with mixed or permanent dentition, than fourth-grade equations. Details of the mathematical procedure and the precision obtained were provided.

Algorithms↗
PubMed2003

[Heritability of insulin sensitivity in twins].

OBJECTIVE: To explore the contribution of genetic and environmental effects to insulin sensitivity. METHODS: The insulin sensitivity of 249 pairs of twins was estimated by use of logarithm transformed homeostasis model assessment (HOMA), of whom 169 pairs were monozygous and 80 pairs dizygous. To formulate a univariate genetic model for the variation of insulin sensitivity, the relative influences of gene and environment on the insulin sensitivity were divided into four contributing components as A (additive effects of alleles),D (dominance effects) C (common environmental effects) and E (specific environmental effects). Heritability of insulin sensitivity was estimated by maximum likelihood method, which included the influences of age and sex on model. RESULTS: The influence of age on insulin sensitivity was not significant chi(2)=1.851 P=0.604 . The AE-model fitted the data best. The heritability of insulin sensitivity was 0.35 in males and 0.46 in females, respectively. CONCLUSION: 35% of the variance in insulin sensitivity was due to additive effects in males and 46% due to additive effects in females in this twin study.

Adult↗
PubMed2004

[A twin study of association of beta3AR Trp64Arg polymorphisms with insulin sensitivity].

OBJECTIVE: To investigate the influences of beta3 adrenergic receptor(beta3AR) Trp64Arg polymorphism on insulin resistance. METHODS: The insulin sensitivity was estimated with logarithm transformed homeostasis model assessment (HOMA). We enrolled 88 pairs of dizygotic twins for this study. We performed PCR-RFLP analysis to detect the Trp64Arg variants with BstO I digestion. RESULTS: The genotypic frequencies of Trp64Trp, Trp64Arg and Arg64Arg were 71.5%, 26.7% and 1.7%. Those who carried Trp64Arg variant appeared to have lower insulin sensitivity compared to the one who didn't, but had no significance(P=0.145). Body mass index (BMI) had shown to be weakly positive correlated with lgHOMA. We found no significant association between the Trp64Arg variant and BMI. CONCLUSION: The presence of the Arg64 allele in beta3AR gene may predispose patients to insulin resistance, and further study with larger sample size may help to confirm the result.

Arginine↗
PubMedDate not supplied

[Population genetic analysis of the new dog breed Elo].

The breeding of the dog breed Elo was started in 1987. This dog breed was established by using 16 dogs of nine different breeds. All pedigree information of the dogs from 1987 to 2002 was included for the analysis of the proportion of genes of the different founder breeds, of the inbreeding coefficient, and relationship coefficients. Additionally, the number of died puppies per litter were investigated. The Eurasian dog breed contributed about 48% of the genes in the whole Elo dog population. Old English sheepdog and Chow Chow contributed about 23% and 10% of the genes. The other dog breeds were of minor importance. The mean inbreeding and relationship coefficients of the whole Elo dog population were 12.04% and 19.22%, respectively. With the exception of 3.5% of animals, all Elo dogs were related to each other. The mean litter size was 6.39 puppies. The percentage of stillborn puppies per litter averaged at 9.47%. The inbreeding coefficients of the puppies and of their dams, the age of the sire and the dam at the time of birth of the puppies, the litter size, the puppies' year of birth and the proportion of genes of the Chow Chow showed a significant effect on the number of stillborn puppies per litter. The heritability for the frequency of stillborn puppies was estimated using a linear animal model. After transformation of the linear estimates to the underlying liability scale, the heritability amounted to h2 = 0.15.

Animals↗
PubMed2004

[Effect of osteopractic total flavone on bone mineral density and bone histomorphometry in ovariectomized rats].

OBJECTIVE: To observe the effect of osteopractic total flavone on bone histomorphometry of osteoporosis model in rath with ovariectomized female rat models. METHOD: The ovariectomy-induced model, bone sliceswith calcium, pigmentation, and Leica Qwin image analysis system were adopted on bone histomorphometry. RESULT: As compared with the model group, the effect of small-dose group and middle-dose group of osteopractic total flavone on TBV% of shankbone increased significantly; the effect of small-dose group and middle-dose group of osteopractic total flavone on TRS% of shankbone reduced significantly and TFS%, AFS%, MAR, BFR of shankbone reduced obviously; the effect of middle-dose group of osteopractic total flavone on OSW and mAR reduced obviously, the effect of small-dose group of osteopractic total flavone on them had the tendency of reducing, but there was no statistical significance. CONCLUSION: The ovariectomized rats having been fed with osteopractic total flavone for 6 months, TBV% increased significantly while TRS%, AFS%, MAR, BFR, OSW, and mAR reduced obviously. It indicates that the therapeutical effect of osteopractic total flavone on ovariectomy-induced osteoporosis model is significant. And the ovariectomy-induced osteoporosis model is a high transformative type of osteoporosis model in which bone absorption is higher than bone formation.

Animals↗
PubMed2006

Landscape of current toxicity databases and database standards.

Having readily available historical information for modeling toxicity has become important throughout the various stages of research and development. The high cost of late-phase attrition and recent international regulatory legislations have made even more acute the need to be able to mine the fragmented data and information available across diverse databases. In addition, the general trend to accelerate regulatory processes globally makes the effective use of existing data an imperative. To achieve efficient screening, develop profiles and gain the ability to cross reference, databases must be interoperated to allow data exchange and integration. Several database standards and controlled vocabulary initiatives have been used in the development of toxicity data models to transform the current landscape. This review describes the major databases of toxicological information now available, and provides a simple example of standardization that demonstrates the benefits of a toxicity database containing such qualified data.

Animals↗
PubMed1992

Vascular endothelial growth factor. Regulation by cell differentiation and activated second messenger pathways.

Vascular endothelial growth factor (VEGF) is an angiogenic polypeptide that has been isolated from a variety of tumorigenic and nontransformed cell lines. Because of the importance of blood vessel growth to cell and tissue development, we have examined VEGF gene expression in a variety of mouse tissues and rodent models of cellular differentiation. Using a cloned murine VEGF cDNA we show that VEGF mRNA is expressed at relatively low levels in many adult mouse tissues examined. However, this message is dramatically induced in two models of cell differentiation: 3T3-adipose conversion and C2C12 myogenic differentiation. VEGF protein secretion is also induced in adipocyte differentiation. VEGF mRNA is markedly regulated in a pheochromocytoma (PC12) cell model of transformation and differentiation. The transformed undifferentiated cells express moderate levels of VEGF mRNA and this expression is virtually extinguished when cells differentiate into non-malignant neuron-like cells. Experiments employing phorbol esters and cAMP analogues indicate that VEGF mRNA expression is stimulated in preadipocytes by both protein kinase C and protein kinase A-mediated pathways. These results suggest that VEGF mRNA levels are closely linked to the process of cellular differentiation; they also clearly demonstrate that expression of this angiogenic factor is specifically regulated in a transformed cell line, possibly via aberrant activation of cellular second messenger pathways.

3T3 Cells↗
PubMedDate not supplied

Effects of cognitive and pharmacologic strategies on analogued labor pain.

Using an analogued labor pain procedure, the efficacy of combinations of five cognitive and one pharmacologic approach to pain management was examined. Nulliparous undergraduates (N = 120) were randomly assigned to 1 of 12 groups. Cognitive groups included: systematic desensitization (SYS DENS); sensory description (SEN DESC); sensory transformation (ST); modeling (M); and relaxation (R); combined groups: SYS DENS, SEN DESC, and ST; SEN DESC, ST, and R; SEN DESC, R, ST, and Demerol. Pharmacologic groups included expected Demerol, did not expect Demerol, placebo, and no treatment control. Subjects assigned to a cognitive group received two 1-hour training sessions 1 week apart. Remaining subjects were given the assigned pharmacologic treatment one-half hour prior to the exposure to the painful stimulus. Assessment of the cognitive and pharmacologic approaches were made in a 1-hour session involving twenty 80-second exposures to a laboratory pain stimulus patterned to resemble labor contractions. Dependent variables included self-reported pain, blood pressure, frontalis electromyograph, heart rate, and respiratory rate. Significant treatment by trials and treatment effects were found for self-reported pain. No other effects achieved statistical significance.

Adult↗
PubMed1983

[Cervical condyloma and dysplasia: histological and virological correlation apropos of 100 cases].

Colposcopy and cytology have pointed at the frequency of cervical condylomas with special consideration to flat types. The association condyloma/dysplasia and the behavior of carcinomas in situ as sexually transmitted diseases, suggest that human papillomavirus (H. P. V.) could play a role in cervical cancer. 100 patients have undergone examination for coloscopy, cytology, histology and virology. Dysplastic features were observed in 47 p. 100 and led to classify the lesions in 3 groups according to their importance: condylomas (53 p. 100), dysplastic condylomas (25 p. 100) with predominance of condylomatous pattern, dysplasia (22 p. 100) with a predominant dysplastic pattern. Virologic data were correlated with this classification and demonstrate a dramatic relationship between viral disappearance and the presence of dysplastic features. Virus was found in 83 p. 100 of pure condylomas, 16 p. 100 of dysplastic condylomas and 0 p. 100 of condylomatous dysplasias. Such a phenomenon of viral absence is observed in animal models (malignant transformation of Shope's papilloma): this could be a new argument to suspect the carcinogenic potential of H. P. V. for cervix and external genitalia.

Adolescent↗
PubMed1981

[Principal fields of research into the pathogenesis of gliomas (author's transl)].

Our hypotheses concerning the pathogenesis of gliomas are based upon the study of numerous animal models. Malignant transformation is probably related to changes in the genome of somatic cells, caused either by chemical or physical agents or by the addition of viral material. Promotion of the tumor, which results in its clinical expression, would involve the failure of a hypothetical immune mechanism of surveillance. At the present time, we have no direct proof of the intervention of such various initiation or tumor-promotion factors in the pathogenesis of human gliomas.

Animals↗
PubMedDate not supplied

[Prodromal period of the first episode of schizophrenia].

The article is a review of the literature on the prodromal period of the first episode of schizophrenia. According to the literature, the first episode of schizophrenia is usually preceded by a few years of prodromal period including non-specific behavioural and affective disturbances as well as psychotic-like and prepsychotic symptoms. The concepts formulated so far concerning a definition of prodromal symptoms were discussed. The data were summarized on clinical characteristics of the prodromal period such as symptomatology, frequency of symptoms, dynamics of changes and the period of occurrence of the prodromal symptoms. Four hypothetical models of transformation of prodromal symptoms into psychotic process were described. Also, the importance of the prodromal symptoms of the first episode of schizophrenia for early diagnosis and therapy of schizophrenia was discussed with regard to currently performed programs of early interventions in schizophrenia.

Disease Progression↗
PubMed1998

TAMBIS--Transparent Access to Multiple Bioinformatics Information Sources.

The TAMBIS project aims to provide transparent access to disparate biological databases and analysis tools, enabling users to utilize a wide range of resources with the minimum of effort. A prototype system has been developed that includes a knowledge base of biological terminology (the biological Concept Model), a model of the underlying data sources (the Source Model) and a 'knowledge-driven' user interface. Biological concepts are captured in the knowledge base using a description logic called GRAIL. The Concept Model provides the user with the concepts necessary to construct a wide range of multiple-source queries, and the user interface provides a flexible means of constructing and manipulating those queries. The Source Model provides a description of the underlying sources and mappings between terms used in the sources and terms in the biological Concept Model. The Concept Model and Source Model provide a level of indirection that shields the user from source details, providing a high level of source transparency. Source independent, declarative queries formed from terms in the Concept Model are transformed into a set of source dependent, executable procedures. Query formulation, translation and execution is demonstrated using a working example.

Artificial Intelligence↗
PubMed2000

Robust transformation with applications to structural equation modelling.

Data sets in social and behavioural sciences are seldom normal. Influential cases or outliers can lead to inappropriate solutions and problematic conclusions in structural equation modelling. By giving a proper weight to each case, the influence of outliers on a robust procedure can be minimized. We propose using a robust procedure as a transformation technique, generating a new data matrix that can be analysed by a variety of multivariate methods. Mardia's multivariate skewness and kurtosis statistics are used to measure the effect of the transformation in achieving approximate normality. Since the transformation makes the data approximately normal, applying a classical normal theory based procedure to the transformed data gives more efficient parameter estimates. Three procedures for parameter evaluation and model testing are discussed. Six examples illustrate the various aspects with the robust transformation.

Humans↗