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PubMed2000

[Genetic epidemiological study on non-insulin dependent diabetes mellitus].

OBJECTIVE: To study the general genetic pattern of non-insulin dependent diabetes mellitus patients. METHODS: 1,608 children were investigated for NIDDM family history, and 280 nuclear families were collected. RESULTS: The prevalence rates of NIDDM among first-degree relatives (2.38%), the parents (26.00%), the siblings (2.44%) and the offsprings (1.24%) were higher than that in general population respectively. The s/q was 10.17 by Penrose method, which was close to 1/q(1/2). The p(0) was 0.0244 by simple segregation analysis, which was lower than 0.10. The heritability of NIDDM was 0.54, using the Falconer Threshold Model. CONCLUSION: NIDDM has a familial aggregation, but not fit to the mono-genetic models. NIDDM has the feature of multifactorial inheritance.

Adult↗

PubMed1992

Does chronic lung failure lead to cognitive failure?

This study seeks to find out whether impaired cognition is associated with Chronic Obstructive Pulmonary Disease (COPD). Two experiments have been carried out to address two aspects of selective attention: a focused attention paradigm with a random and a facilitated condition and a divided attention paradigm with and without interference. Twenty-eight COPD patients and 28 matched healthy controls took part in both experiments. Reaction time (RT) was the variable considered. COPD patients had slower RTs than controls, however facilitation and interference had the same effect on both groups. No correlation was found between neuropsychological measures and lung failure indices. A threshold model in the lung-failure/brain-failure trade-off is envisaged.

Adult↗

PubMedDate not supplied

[Gutteral pouch tympany in German warmblood foals: influence of sex, inbreeding and blood proportions of founding breeds as well as estimation of heritability].

The objective of the present study was to analyse the importance of the influences of sex, inbreeding coefficient, proportion of genes of the original breeds and the additive genetic contribution to the occurrence of guttural pouch tympany in foals belonging to German Warmblood breeds. Foals affected by guttural pouch tympany were ascertained in the Clinic of Horses, School of Veterinary Medicine Hannover. This data set comprised 22 German Warmblood foals with guttural pouch tympany, which were patients of the Clinic for Horses between 1994 and 2001. Information on the pedigrees and all available relatives of these patients allowed us to group the affected foals into five families with a total of 289 animals. Female foals were significantly more often affected by guttural pouch tympany. The difference was 16.6% in favour of female foals. The size of the inbreeding coefficient was not important for the occurrence of guttural pouch tympany. The proportion of the genes of the breeds Arabian, Thoroughbred and Trakehner were not significantly different from a randomly selected sample of 10% of foals born in the same birth years and the same region. The heritability estimates for the frequency of guttural pouch tympany using a threshold model was 0.81 +/- 0.16. This is the first report that could show a genetic component responsible for guttural pouch tympany in horses.

Animals↗

PubMed1992

A population-based twin study of alcoholism in women.

OBJECTIVE: To clarify the role of genetic factors in the etiology of alcoholism in women. DESIGN AND SETTING: Personal structured psychiatric interviews conducted by researchers "blinded" to the status of the co-twin in an epidemiologic sample of 1030 female-female twin pairs of known zygosity from the population-based Virginia Twin Registry. MEASURES: Three definitions of lifetime prevalence of alcoholism based on Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised criteria: (1) alcoholism with tolerance or dependence; (2) alcoholism with or without tolerance-dependence; and (3) alcoholism with or without tolerance-dependence or problem drinking. RESULTS: Using narrow, intermediate, or broad definitions, the probandwise concordance for alcoholism was consistently higher in monozygotic than in dizygotic twin pairs. Multifactorial threshold models suggested that the heritability of liability to alcoholism in women is in the range of 50% to 60%. CONCLUSIONS: The results support the hypothesis that genetic factors play a major role in the etiology of alcoholism in women. Women should be well represented in the efforts currently under way to elucidate the molecular basis of the genetic susceptibility to alcoholism.

Alcoholism↗

PubMed2003

[Population genetic analysis of the heritability of gutteral pouch tympany in Arabian purebred foals].

The objective of the present study was to analyse the importance of the influences of the sex, inbreeding coefficient and the additive genetic contribution to the occurrence of guttural pouch tympany in Arabian foals. Horses affected by guttural pouch tympany were ascertained in the Clinic for Horses, School of Veterinary Medicine Hannover. The data comprised 27 Arabian purebred foals with guttural pouch tympany. Of these 27 animals 22 were patients of the Clinic for Horses between 1994 and 2001 and 5 Arabian foals were sampled on the studs. Information on the pedigrees of these patients allowed us to sort in the affected foals into four families with a total of 276 animals. Female foals were more often affected by guttural pouch tympany. The difference was 11.9% in favour of female foals. The size of the inbreeding coefficient was not important for the occurrence of guttural pouch tympany. The heritability estimate for the frequency of guttural pouch tympany using a threshold model was 0.49 +/- 0.28. This is the first report that could show a genetic component responsible for guttural pouch tympany in foals.

Animals↗

PubMed2003

Investigation of albinism genes in congenital esotropia.

PURPOSE: Esotropia is a feature of albinism. Amongst esotropic patients there may be mild unrecognised albinos. Oculocutaneous albinism shares several clinical features with congenital esotropia. It is well known that mammals with oculocutaneous albinism have misrouted retinal ganglion cell axons, most likely caused by the absence of melanin or DOPA during development. We investigated the hypothesis that mutations in the albinism genes Tyrosinase, the P Gene, and TYRP1 may also be responsible for congenital esotropia via a similar mechanism. METHODS: We screened these three genes in 21 families with congenital esotropia using single stranded conformational polymorphism analysis. RESULTS: No rare sequence variants segregating with esoptopia were detected. A novel silent mutation of the TYRP1 gene was identified in one pedigree but is not likely to be causative. Several previously reported common polymorphisms were detected but do not segregate with disease in this population. CONCLUSIONS: Rare mutations of these genes do not appear to be responsible for congenital esotropia. Although we found no evidence for segregation of common variants with disease, these require further investigation for a possible contribution to a complex threshold model. Several lines of evidence indicate a genetic componenet of congenital esotropia, however, this is the first investigation of candidate genes for this disorder.

Albinism, Oculocutaneous↗

PubMed1992

Selection bias in genetic-epidemiological studies of cleft lip and palate.

The possible impact of selection bias in genetic and epidemiological studies of cleft lip and palate was studied, using three nationwide ascertainment sources and an autopsy study in a 10% sample of the Danish population. A total of 670 cases were identified. Two national record systems, when used together, were found suitable for ascertaining facial cleft in live births. More than 95% ascertainment was obtained by means of surgical files for cleft lip (with or without cleft palate) without associated malformations/syndromes. However, surgical files could be a poor source for studying isolated cleft palate (CP) (only a 60% and biased ascertainment), and they cannot be used to study the prevalence of associated malformations or syndromes in facial cleft cases. The male:female ratio was 0.88 in surgically treated cases of CP and was 1.5 in nonoperated CP cases, making the overall sex ratio for CP 1.1 (95% confidence limits 0.86-1.4) The sex ratio for CP without associated malformation was 1.1 (95% confidence limits 0.84-1.6). One of the major test criteria in CP multifactorial threshold models (higher CP liability among male CP relatives) must be reconsidered, if other investigations confirm that a CP sex-ratio reversal to male predominance occurs when high ascertainment is achieved.

Cleft Lip↗

PubMed1978

Genetic control of susceptibility to autologous immune complex glomerulonephritis in inbred rat strains.

Twelve inbred rat strains were tested for their susceptibility to autologous immune complex glomerulonephritis (AIC) after a single injection of a primary tubular epithelial fraction emulsified in Freund's complete adjuvant. Six strains (Lewis, AS, BDV, L.BDV, AS2, L.AS2) showed high responsiveness in terms of proteinuria and immunohistological changes, which could be observed after 3 months. Strains BN, AVN and DA were completely resistant, even after 6 months of observation. An additional adjuvant (pertussis vaccine) did not break non-responsiveness in one of these strains (BN). Strains which share the Lewis strain genetic background (L.BN, L.AVN and L.WP) seemed to be at least weakly susceptible to AIC. A close association between susceptibility and the major histocompatibility haplotypes is demonstrated in segregation studies involving Lewis, L.BN and BN rats. A threshold model of AIC susceptibility, based on the action of major histocompatibility-linked genes and background genes, is suggested.

Animals↗

PubMed1979

[Inheritance of human fingerprints].

Polygenic threshold model of finger dermatoglyphics inheritance is worked out on the basis of family and population data. According to the model, ulnar loops are subthreshold patterns, which transforms into whorl or arch under the control of SU and SR gene complexes. Epistasis-hypostasis interactions take place between genes of SU and SR complexes. Classification of phenotypes for finger dermatoglyphics is offered and the frequency of these phenotypes in three populational samples of Kiev is studied.

Dermatoglyphics↗

PubMedDate not supplied

Paclitaxel pharmacokinetics and response to chemotherapy in patients with advanced cancer treated with a weekly regimen.

BACKGROUND: Paclitaxel pharmacokinetics were shown to be related to toxicity and survival. PATIENTS AND METHODS: We evaluated the effects of time above paclitaxel concentrations of 0.05 micromol/l (T(>0.05) and systemic exposures (AUC) to total and unbound paclitaxel (tPAC, uPAC) on response in patients with advanced cancer treated with weekly 1-h or 3-h infusions. RESULTS: After 6 weeks of therapy (WOT), 13 out of 21 assessable patients showed either partial response (PR) or stable disease (SD), while 8 had progressive disease (PD). As compared to patients with PD, those with PR or SD showed similar AUCs to uPAC and tPAC but higher (p < 0.05) T (>0.05). Patients with T(>0.05) > or = 20.7 hours had lower probability (p < 0.05) to progress within 12 WOT. CONCLUSION: Taking the heterogeneity of the studied tumor types into account, we found T(>0.05) to be associated with response to treatment. This emphasizes the value of threshold models for the investigation of paclitaxel pharmacodynamics.

Adult↗

PubMedDate not supplied

[Construction of an ultrasound clinical scale for the diagnosis of choledocolithiasis].

OBJECTIVE: to describe the construction of a clinical ultrasonographic scale for diagnosing choledocholithiasis. MATERIAL AND METHODS: A retrospective study of diagnostic tests, done through files of patients older than 18 years old with diagnosis related to having jaundice, who received care at three hospital facilities in Culiacan, Sinaloa, Mexico from 1998 to 1999, was carried out. Clinical, lab and cabinet data were collected. Gold standards were considered endoscopic retrograde cholangio-pancreatography as well as exploratory laparotomy. A diagnostic scale for choledocholithiasis was constructed through logistic regression and multivariate analysis using principal components. Sensitivity, specificity, prediction values, negative and positive likelihood ratio (LR) and ROC curves were estimated. The threshold model was applied for medical decision making. RESULTS: For detecting choledocholithiasis the scale's sensitivity was 98%, specificity was 95%, positive and negative predictive values were 95% and 97%, respectively. The estimated positive LR was 19.6 and negative 0.02. CONCLUSIONS: In adult patients up to 70 years with acute jaundice evolution, the scale can diagnose securely choledocholithiasis. The pretest prevalence and/ or probability do not affect importantly its accuracy for medical decision making.

Adolescent↗

PubMed1991

[Epidemiologic and genetic analysis of veterinary data of German Brown cattle].

In totally 3740 cows of the breed German Brown Swiss distributed over 115 herds risk factors for the occurrence of diseases were analysed using a threshold model. Disease data were recorded by ten practitioners in southern Bavaria. The most frequent diseases were fertility disorders, followed by metabolic, udder and calving disorders. The influence of the herds could demonstrated clearly for all diseases analysed. The effect of the lactation number contributed significantly to the frequency of milk fever, mastitis, retained placenta, endometritis/metritis and ovary cysts. Heritability estimates vary between h2 = 0.5% and h2 = 4.2% with exception of anestrus/acyclia (h2 = 8.8%). With higher milk yield of cows the disease frequencies increase, especially fertility diseases. However, increasing herd milk yield is associated with decreasing disease frequencies. A depression of A.I.-parameters and an increase of culling rate caused by diseases could be observed. In the case of the occurrence of uterus- and ovary disorders days open are elongated by 58 days in comparison to cows without diseases. Recording of disease data for use in electronic data processing seems necessary, in order to diminish production diseases by breeding and herd control programmes. An important prerequisite in organization of disease data recording is an efficient cooperation between the veterinary practitioner, farmer, inseminator and the official milk recording organisation.

Animals↗

PubMed1991

[Analysis of environmentally-conditioned and genetic influences on the frequency of hip joint dysplasia in German Shepherd dogs].

The importance of environmental and genetic influences on the frequency of hip dysplasia was studied in 10,595 German shepherd dogs. Systematic effects were analysed using mixed linear and mixed nonlinear threshold models. Following effects were regarded in the models applied: sire and mother of the dog as random effects, age at x-raying, sex, birth year and season of the x-rayed dogs, litter size, percentage of x-rayed dogs in each litter and sex ratio of the litter as fixed effects. Sire, mother, sex and age at x-raying showed significant influence on the occurrence of hip dysplasia. The heritability estimates in a hierarchical data design (sire, mother within sire) for the polychotomous trait hip dysplasia were for full sibs h2 = 0.30, for maternal half sibs h2 = 0, 48, and for paternal half sibs h2 = 0.11. Only the heritability estimates of the paternal half sibs seem to be reliable because kennel and breeder effects are confounded with the mother effect. Analysing the frequency of hip dysplasia as all-or-none traits, the heritability estimates were usually lowered by 50%. Selection programmes to reduce frequency of hip dysplasia can be improved if the estimation of breeding values with respect to environmental effects and frequency of hip dysplasia in all relatives will be implemented.

Analysis of Variance↗

PubMed1991

[Genetic determination of rheumatoid arthritis].

The study on the nature of genetic determination of the definite rheumatoid arthritis (RA) and its forms was carried out, based on the material comprising clinical data on 189 probands and their 1st and 2nd degree relatives (713 subjects) which is contained in the computer Family Data Bank at the Department of Epidemiology and Genetics of this institute. The heritability coefficient "in narrow sense" (80%) obtained within the framework of the multifactorial threshold model confirmed once more important role of genetic factors in the appearance of the disease. The study of genetic heterogeneity within the framework of the Ch. Smith's and T. Reich's models failed to reveal any independent genetically RA forms. An assumption of the essential role of the genes localized in the X chromosome, based on diverse susceptibility of sexes, received no conformation. It has been shown that the RA distribution in the population and families may well be described by means of a variant of the single autosomal two-allele locus model with incomplete and differentiated for two sexes penetrance. The model parameters obtained, a particular penetrance of the mutant homozygote in both sexes equalling 100%, and penetrance of the normal homozygote equalling 0 in men and reaching 0 (0.028%) in women testify to a very essential influence of the major gene on determination of RA.

Arthritis, Rheumatoid↗

PubMed1990

[Are there sex differences in the manifestation of hyperkinetic syndrome?].

Thirty-nine children (14 girls and 25 boys) were compared for sex differences in the severity of the hyperactive syndrome. A more severe form of the disorder in hyperactive girls suggested by the sex-related multiple threshold model of inheritance could not be shown. The severity of the disorder is considered to be the result of symptom severity combined with the effect on everyday life. The rating instruments used were the Conners Rating Scale and the Steinhausen Global Assessment Scale for Children and Adolescents. No significant differences were found for the symptoms impulsivity, inattention, and overactivity as assessed with the Yale Children's Inventory. However, the boys tended to be even more impulsive than the girls. The results were controlled for age, adverse family and social circumstances and gender-oriented expectations.

Attention Deficit Disorder with Hyperactivity↗

PubMed1989

Evaluating genetic association among ovarian, breast, and endometrial cancer: evidence for a breast/ovarian cancer relationship.

The possibility of a genetic relationship between ovarian, breast, and endometrial cancer was investigated in data from a large multicenter, population-based, case-control study, the Cancer and Steroid Hormone Study conducted by the Centers for Disease Control (CDC). Age-adjusted relative risks (RRs) for mothers and sisters of 493 ovarian cancer cases, 895 breast cancer cases, and 143 endometrial cancer cases versus 4,754 controls were calculated. Significantly elevated age-adjusted RRs were found for ovarian cancer (RR = 2.8; 95% confidence interval [CI] = 1.6-4.9) and breast cancer (RR = 1.6; 95% CI = 1.1-2.1) among relatives of ovarian cancer probands and for breast cancer (RR = 2.1; 95% CI = 1.7-2.5) and ovarian cancer (RR = 1.7; 95% CI = 1.0-2.0) among relatives of breast cancer probands. Relatives of endometrial cancer probands had an elevated RR for endometrial cancer only (RR = 2.7; 95% CI = 1.6-4.8). The genetic relationship between ovarian, breast, and endometrial cancer was tested using a multivariate polygenic threshold model developed by Smith (1976), which was modified to accommodate three classes of probands. Estimates of heritability for ovarian, breast, and endometrial cancer were 40%, 56%, and 52%, respectively. There was a significant genetic correlation between ovarian and breast cancer (R12 = .484). Evidence for significant genetic overlap between endometrial cancer and either ovarian or breast cancer was not found. These results suggest the existence of a familial breast/ovarian cancer syndrome. Endometrial cancer, while heritable, appears to be genetically unrelated.

Adult↗

PubMed1989

Mechanisms of contour perception in monkey visual cortex. II. Contours bridging gaps.

We have studied the mechanism of contour perception by recording from neurons in the visual cortex of alert rhesus monkeys. We used stimuli in which human observers perceive anomalous contours: A moving pair of notches in 2 bright rectangles mimicked an overlaying dark bar. For control, the notches were closed by thin lines so that the anomalous contours disappeared or half of the figure was blanked, with a similar effect. Orientation-selective neurons were studied. With the receptive fields centered in the gap, 23 of 72 (32%) neurons tested in area V2 responded to the moving "bar" even though the stimulus spared their response fields, and when the notches were closed, their responses were reduced or abolished. Likewise, when half of the figure was removed, the neurons usually failed to respond. Neurons with receptive fields within 4 degrees of the fovea signaled anomalous contours bridging gaps of 1 degree-3.5 degrees. The anomalous-contour responses were compared quantitatively with response field profiles and length-summation curves and found to exceed the predictions by linear-summation and summation-to-threshold models. Summation models also fail to explain the effect of closing lines which add only negligible amounts of light. In V1, only one of 26 neurons tested showed comparable responses, and only with a narrow gap. The others responded only when the stimulus invaded the response field and did not show the effect of closing lines, or failed to respond at all. The contour responses in V2, the nonadditivity, and the effect of closure can be explained by the previously proposed model (Peterhans et al., 1986), assuming that the corners excite end-stopped fields orthogonal to the contour whose signals are pooled in the contour neurons.

Animals↗

PubMed1986

Major gene determination of liability to cleft lip with or without cleft palate: a multiracial view.

Despite nearly half a century of intensive investigation, the etiology of non-syndromic cleft lip with or without cleft palate (CL +/- P) remains unknown because most studies have been descriptive rather than analytic. This study summarizes rigorous analyses of CL +/- P in the families of non-syndromic, CL +/- P surgical probands from three populations: Denmark, London, England, and Shanghai, China. Three main conclusions could be drawn from the results. The data provide no support for the multifactorial threshold model summarized by Carter (1976) and most often proposed to explain the etiology of CL +/- P. Each dataset provides evidence that there may be a major gene for liability to CL +/- P in at least a portion of cases. The data are consistent with possible genetic heterogeneity in CL +/- P.

China↗