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Biomedical subjects

M C King

Publications and source records attributed to M C King.

At least 127 records · Page 7Linked to original sources
PubMed1989

Genetic epidemiology of persistent islet cell antibodies among IDDM patients.

The persistence of cytoplasmic islet cell antibodies (ICA) more than a year after diagnosis of insulin-dependent diabetes mellitus (IDDM) was investigated in 43 families with at least two children with IDDM. The prevalence of persistent ICA among IDDM patients was 16%. Persistence of ICA appeared to be familial in that siblings with IDDM were significantly more concordant for the presence or for the absence of ICA than expected by chance (P = 0.04). Patients with persistent ICA were older on average at onset of IDDM than patients without persistent ICA after adjusting for duration of disease (P = 0.004). Persistence of ICA was not significantly associated with HLA DR type, immunoglobulin genotype, insulin allele class, sex, history of viral diseases, or prior vaccinations.

Autoantibodies↗
PubMed1989

Child maltreatment: family characteristics and developmental consequences.

Although it has been suggested that certain family characteristics and experiences may mediate the effects of child abuse and neglect, pertinent research conceptualized from this perspective is limited. In this literature review, the cognitive, social, and emotional outcomes for maltreated children are reviewed, and the literature concerned with a variety of family characteristics that may potentially mediate or compensate for the effects of maltreatment is examined. The inherent developmental perspective in conjunction with a family systems orientation reflects a nursing perspective that can be used to understand and intervene with the multivariate phenomenon.

Child↗
PubMed1989

Oncogenes and human breast cancer.

The role of oncogenes in breast tumorigenesis is unclear. Alterations and/or amplification of several oncogene sequences have been observed in primary human breast tumors, in breast tumor cell lines, and in mammary tumors in model systems. In principle, such alterations could be sites of primary lesions for human breast cancer, causes of tumor progression or metastasis, or simply secondary lesions of highly aberrant tumor genomes. The present study tested genetic linkage of breast cancer susceptibility to nine oncogenes in 12 extended families including 87 affected individuals. Lod scores for close linkage of each candidate sequence to breast cancer were -19.6 for HRAS, -12.3 for KRAS2, -1.0 for NRAS, -6.0 for MYC, -6.1 for MYB, -8.2 for ERBA2, -7.9 for INT2, and -5.1 for RAF1. Regions of chromosome 11p associated with tumor homozygosity and the region of 3p carrying the gene for Von Hippel-Lindau disease could also be excluded from linkage to human breast cancer. The 5-kb allele of the MOS oncogene, previously proposed to be associated with breast cancer, was absent in these families, suggesting that polymorphism at this locus is not associated with inherited susceptibility. These results strongly suggest that oncogenes are not the sites of primary alterations leading to breast cancer. On the other hand, alterations in one or more of these sequences may be associated with tumor progression.

Breast Neoplasms↗
PubMed1989

Abused women: dispelling myths and encouraging intervention.

Our society abounds with myths and misperceptions in relation to the battering of women. These myths impede the identification of women who are experiencing violence and abuse, and inhibit appropriate intervention. Abuse is not too private a matter to assess for, nor does abuse affect only poor black or Hispanic women. No woman deserves to be beaten. Women do not like or seek out abuse. Abused women are courageous, competent women; what abused women have in common is that they are threatened and controlled by a male partner and live under the constant fear of violence and abuse. Raising one's consciousness about the victimization and oppression of women in our society, and uncovering the myths which leave practitioners powerless and ineffective agents of change for women are important tasks for health care providers. By focusing attention on this enormous health problem, clinicians can provide a leadership role in using health care responses that actually empower women to take control of their own lives.

Attitude of Health Personnel↗
PubMed1989

Evidence of genetic influence on central body fat in middle-aged twins.

The heritability of centrally and peripherally deposited subcutaneous body fat, as measured by thickness of subscapular and triceps skinfolds respectively, was examined in 173 monozygotic and 178 dizygotic pairs of white male twins, ages 54 to 65 years, who participated in the second examination of the National Heart, Lung, and Blood Institute's Twin Study. The heritability of two indices of body fat distribution (subscapular/triceps ratio and subscapular-triceps difference) and two indices of overall obesity (body mass index and sum of skinfolds) were also assessed. Evidence for a genetic influence on central deposition of body fat was suggested in that the classical estimate of heritability for subscapular skinfold thickness was 0.77 (p less than 0.0001). After adjusting subscapular skinfold for the overall level of obesity, heritability was reduced but remained highly significant (0.40, p = 0.003). Heritability estimates for triceps skinfold thickness and for the two fat distribution indices were substantially lower and were not statistically significant after adjustment for overall obesity. High classical estimates of heritability were also observed for both measures of overall obesity: 0.70 for BMI and 0.73 for sum of skinfolds. However, these two estimates were biased upward because of lower total variances among monozygotic compared to dizygotic twins in this sample. The more conservative and unbiased among-component estimates also suggested substantial heritability for each measure (0.35, p = 0.08 and 0.53, p = 0.01, respectively). The heritability of overall obesity emphasizes the importance of adjusting measures of fat distribution for overall obesity before assessing its heritability.

Adipose Tissue↗
PubMed1988

Inheritance of human breast cancer: evidence for autosomal dominant transmission in high-risk families.

Segregation analysis of breast cancer in families can provide the logical basis and the specific genetic models for mapping and identifying genes responsible for human breast cancer. Patterns of breast cancer occurrence in families were investigated by complex segregation analysis. In a sample of 1579 nuclear families ascertained through a population-based series of probands, an autosomal dominant model with a highly penetrant susceptibility allele fully explained disease clustering. From the maximum-likelihood Mendelian model, the frequency of the susceptibility allele was 0.0006 in the general population, and lifetime risk of breast cancer was 0.82 among susceptible women and 0.08 among women without the susceptibility allele. Inherited susceptibility affected only 4% of families in the sample: multiple cases of this relatively common disease occurred in other families by chance. The same genetic models, with higher gene frequency, explained disease clustering in an extended kindred at high risk of breast cancer. Evidence for a highly penetrant, autosomal dominant susceptibility allele for breast cancer in a high-risk family and the general population suggests that high-risk families can serve as models for understanding breast cancer in the population as a whole.

Adult↗
PubMed1988

Inheritance of low-density lipoprotein subclass patterns: results of complex segregation analysis.

Heterogeneity in the size of low-density lipoprotein (LDL) particles was used to identify two distinct patterns based on gradient gel electrophoresis analysis. These two phenotypes, LDL subclass pattern A and pattern B, were characterized by a predominance of large, buoyant LDL particles and small, dense LDL particles, respectively. The inheritance of these LDL subclass patterns was investigated in a sample of 61 healthy families including 301 individuals. LDL subclass pattern B was present in 31% of the subjects, with the prevalence varying by gender, age, and (in women) menopausal status. Complex segregation analysis suggested a major locus controlling LDL subclass patterns. The model providing the best fit to the data included a dominant mode of inheritance with a frequency of .25 for the allele determining LDL subclass pattern B and reduced penetrance for men under age 20 and for premenopausal women. Thus, the allele for the LDL subclass pattern characterized by a predominance of small, dense LDL particles appears to be very common in the population, although not usually expressed until adulthood in men and until after menopause in women. The presence of a major gene controlling LDL subclass could explain much of the familial aggregation of lipid and apolipoprotein levels and may be involved in increased risk of coronary heart disease.

Adolescent↗
PubMed1987

Concordance for type 2 (non-insulin-dependent) diabetes mellitus in male twins.

Concordance for Type 2 (non-insulin-dependent) diabetes was determined in 250 monozygotic and 264 dizygotic white male twin pairs who participated in the National Heart, Lung, and Blood Institute Twin Study. These twins were born between 1917 and 1927 and were identified from military records without regard to disease status. We examined surviving members of the cohort twice--at mean ages of 47 and 57 years--and obtained 1-h post-load glucose tests and medication histories. Diagnostic criteria for Type 2 diabetes included a glucose value greater than or equal to 13.9 mmol/l or current use of antidiabetic medication; possible Type 1 (insulin-dependent) diabetic twins were excluded. A strong genetic predisposition to Type 2 diabetes was suggested by 3 lines of evidence from the second examination: (1) 58% of monozygotic co-twins of diabetic twins were themselves diabetic compared with an expected prevalence of 10%; (2) only 1 of 15 originally disease-discordant, monozygotic twin pairs remained discordant for diabetes; and (3) 65% of non-diabetic monozygotic co-twins of diabetic twins had elevated glucose values. Because concordance for diabetes was less than 100% for twins aged 52-65 years and because twins varied in age at onset of disease, non-genetic factors may also influence diabetes development. Among the 19 monozygotic twins pairs discordant for diabetes, diabetic twins did not differ from their non-diabetic co-twins in obesity, diet, alcohol consumption, or education. However, compared with unrelated non-diabetic twins of the same ages, non-diabetic co-twins of diabetic twins gained more weight as adults (p less than 0.02) and had higher glucose levels (p less than 0.03).

Body Weight↗
PubMed1987

Signal processing technique to extract neuronal activity from noise.

A method of extracting extracellularly recorded action potentials from background electronic noise is described. Segments of traces containing stimulus-induced activity are Fourier transformed and the increase in the total power density over that of control noise segments is used as a measure of stimulus-induced neuronal activity. We show first, with observations from the amphibian visual system and mammalian auditory system, that our technique yields similar quantitative information to that obtained from the conventional spike counting method when the recording arrangement is optimal. Moreover, the size and centre of a visual receptive field can be determined even when the evoked action potentials are buried in the background noise. To investigate the potential of this technique further, we have used it to study the auditory responses in the amphibian midbrain. The power spectral density, we demonstrate here, is proportional to the stimulus intensity over a wide range, and varies systematically with stimulus frequency and the direction of sound source. Other possible applications of this technique, together with the theoretical basis for it, are discussed.

Action Potentials↗
PubMed1987

Risk factors for coronary heart disease in adult female twins. Genetic heritability and shared environmental influences.

The contributions of shared genes and shared environments to familial aggregation of coronary heart disease risk factors were investigated by genetic and epidemiologic analysis of 434 adult female twin pairs from the Kaiser-Permanente Twin Registry in Oakland, California, during 1978 and 1979. Initial estimates of genetic heritability were statistically significant for serum levels of high density lipoprotein (HDL) cholesterol, low density lipoprotein (LDL) cholesterol, triglycerides, and Quetelet index, but were only marginally significant for systolic and diastolic blood pressures. These estimates were biased, however, because sisters in the same identical twin pair were more similar than sisters in the same fraternal twin pair not only with respect to shared genes but also with respect to shared environmental and behavioral influences. Heritability was estimated again after adjusting for shared environmental and behavioral effects by multiple regression analysis. Genetic heritability remained significant for HDL cholesterol (0.66), LDL cholesterol (0.88), triglycerides (0.53), and relative weight (0.55) but not for systolic (0.42) and diastolic (0.25) blood pressures. The strong genetic components of the levels of LDL cholesterol, HDL cholesterol, and relative weight may in part explain why some women have high levels of these coronary disease risk factors despite following recommended health behaviors.

Adult↗
PubMed1987

Environmental and behavioral determinants of fasting plasma glucose in women. A matched co-twin analysis.

Comparing results of an unmatched analysis in a sample of unrelated persons created by randomly selecting one twin from each pair with results of a matched monozygotic co-twin analysis provides a means of distinguishing environmental influences from genetic influences on a dependent variable of interest. Determinants of the fasting plasma glucose level were investigated in a large sample of adult female nondiabetic twins from the Kaiser Permanente Twin Registry. In the subsample of unrelated persons, fasting plasma glucose was significantly and positively associated with age, body mass index, uric acid level, and alcohol intake and was significantly inversely related to leisure time physical activity. When monozygotic twins were treated as matched pairs, only the effects of body mass index and alcohol consumption remained significant, whereas the association with leisure time physical activity was greatly reduced and no longer statistically significant. These results suggest that behavioral and therefore alterable aspects of obesity and alcohol consumption influence the fasting plasma glucose level; alcohol consumption may be a risk factor for non-insulin-dependent diabetes mellitus; and common underlying genetic factor(s) may be responsible for the negative association between physical activity and fasting plasma glucose.

Adult↗
PubMed1986

Familial breast cancer in a population-based series.

Breast cancer risks to sisters of breast cancer patients were examined in a population-based series of patients diagnosed in Los Angeles County between 1971 and 1975. Sisters of bilateral patients diagnosed at age 50 years or younger had substantially increased risk (relative risk (RR) = 5.5), and risk was even higher for sisters of bilateral patients diagnosed at age 40 years or younger (RR = 10.5). Half of the breast cancers in sisters of bilateral cases occurred in the family of a single bilateral patient whose disease was diagnosed at age 39 years. Sisters of unilateral patients diagnosed at age 50 years or younger did not have significantly increased risk, but sisters of unilateral patients diagnosed at age 40 years or younger appeared to have increased risk (RR = 2.4). Risk to sisters of bilateral patients was slightly higher if the patient's contralateral diagnoses were less than three years apart than if they were three years apart or greater (RR = 6.3 vs. 3.9), but this difference was not statistically significant.

Adult↗
PubMed1986

Male influences on cervical cancer risk.

Risk factors for squamous cell carcinoma of the uterine cervix were studied among low income, married Hispanic women and their husbands, using a case-control design. A total of 45 eligible cases were identified at public hospitals and community clinics in the San Francisco Bay Area. For each case, a control was selected within two years of age from among Hispanic women seen at the same institution. Thirty-nine matched pairs of couples were interviewed to assess histories of sexual behavior and other possible risk factors. Cases and controls differed markedly in the number of past sexual partners of their husbands. Cases were 5.3 times more likely to be married to husbands who had had 20 or more sexual partners than were controls. Cases and controls themselves did not differ in their number of sexual partners, but cases were younger at first intercourse than were controls. The association with husband's sexual history persisted after adjusting for the woman's number of sexual partners or age at first intercourse. These results support the infectious and venereal transmission of cervical cancer and indicate the important role of husbands in its occurrence in a population with high incidence rates.

Adult↗
PubMed1986

Linkage of cystic fibrosis to two tightly linked DNA markers: joint report from a collaborative study.

A collaborative study involving seven research groups provided an opportunity to investigate the linkage relationships between cystic fibrosis and two DNA marker loci, MET and pJ3.11 (D7S8), on an extended sample of 211 tested families. The maximum lod scores, recombination estimates, and confidence upper bounds (in parentheses) were 91.0 at theta = .004 (.012) for CF and MET, 71.3 at theta = .003 (.011) for CF and D7S8, and 69.3 at theta = .018 (.036) for MET and D7S8. Three-locus analyses yielded best support for the order MET-CF-D7S8, with odds against the alternate orders CF-MET-D7S8 and CF-D7S8-MET of 9:1 and 161:1, respectively. However, the number of observed recombinants was small and only one of the recombinants was jointly informative for all three markers. Significant allelic association was found between CF and both MET and D7S8. Weaker association between the latter two loci is consistent with the order MET-CF-D7S8.

Alleles↗