Biomedical subjects
Publications and source records attributed to H Gordon.
Perineal muscle function was measured in a group of European women 1 year after childbirth by means of a perineometer. There was no correlation between the degree of perineal trauma and subsequent muscle function. The efficiency of the perineal muscles was found to be significantly related to the extent to which women took regular exercise.
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In neonatal rabbit soleus muscle, different motor units were found to contract with widely varying time courses. Analysis of these data suggest that individual motor units are largely homogeneous for muscle fiber type despite the presence of extensive polyinnervation at birth. We suggest that (1) neonatal motor neurons are effectively differentiated into specific types insofar as they preferentially innervate muscle fibers which give rise to different contraction times, and (2) muscle fibers begin their physiological differentiation into twitch types while still polyinnervated. Possible mechanisms underlying the development of a specific pattern of neuromuscular innervation are discussed.
Oncogenes were first identified in neoplastic tissues and were thought to be disseminated by retroviruses. They were shown to cause neoplastic transformation of cells in vitro and were therefore regarded as "the genes that cause cancer." They occur in all eukaryotes including humans. More than 30 oncogenes have been identified, and 28 have already been mapped to the human karyotype. When the protein products of the oncogenes were investigated, they were found to be very similar to known substances that are normally involved in the control of cell division--growth factors, plasma-membrane receptors, modulators of the transduction of exogenous signals through the plasma membrane, and nuclear DNA-binding substances. These discoveries changed the original concept of oncogenes. They are now regarded as playing vital roles in the normal control of mitosis, and they should properly be called mitogenes rather than "oncogenes." Like all other genes, if a mitogene is mutated, rearranged, translocated, or otherwise deranged, its effects will change; it may then become an oncogene that will promote disorderly cell division and thus contribute to the pathogenesis of cancer. In addition to providing new insights into the normal control of mitosis and its neoplastic transformation, the discovery of the mitogenes has suggested new approaches to the early diagnosis of cancer, to a more rational classification of neoplasms based on pathogenesis rather than morphology, and, perhaps, to more rational forms of therapy.
Of 40 patients (16 males and 24 females), 29 had cardiac myxoma(s), 14 had skin pigmentation (lentigo and several types of nevi) which also commonly affected the lips, 6 had skin myxoma(s), and 12 had both pigmentation and myxoma(s); 18 had primary pigmented nodular adrenocortical disease (Cushing syndrome was present in 11); 10 had myxoid mammary fibroadenomas; 9 had testicular tumor(s) (large-cell calcifying Sertoli cell tumor, Leydig cell tumor, or adrenocortical rest tumor, or a combination); and 4 had pituitary adenoma with gigantism or acromegaly. The maximum number of conditions present together was five, occurring in two patients; each of the remaining patients had at least two of the conditions. The overlap, in this sizeable number of patients, of various combinations of the same rare or very rare conditions unlikely to occur together by chance with any degree of frequency is striking evidence for a unique syndrome. The patients were young (mean age at diagnosis of the first component, 18 years). Pathologic involvement tended to be multicentric (heart and skin) and bilateral in paired organs (adrenal, breast, and testis). Thirteen patients (32%) are alive and well. Twelve patients are alive but with complications of cardiac myxoma (in 8), testicular tumors (in 2), residual Cushing syndrome (in 1), or bilateral pulmonary nodules (in 1). Twelve patients are dead: 9 of cardiac myxoma, 1 of intracranial (nonpituitary) tumor, and 2 postoperatively. The status of three is unknown.
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Several methods for investigating genetic heterogeneity for extreme levels of a quantitative trait with hypothesized multiple genetic etiologies require a priori stratification of families and/or identification of distinct phenotypes among affected individuals. We present a statistical approach for detecting genetic heterogeneity that does not rely on either a priori stratification or discrete disease phenotypes. Complex segregation analysis was applied to total serum cholesterol measurements in 709 relatives of 98 healthy index cases selected from 3,666 school children surveyed for lipid levels in Rochester, Minnesota. Thirty-three of the index cases and 109 relatives had hypercholesterolemia (cholesterol levels greater than the 95th percentile for their age and sex). Through application of the mixed genetic model and then estimation of conditional probabilities for having the mutant allele at the major locus, genetic heterogeneity for hypercholesterolemia was indicated. In three of 70 pedigrees with one or more hypercholesterolemics, there is strong evidence for segregation at a major locus. In the remaining pedigrees, only polygene variation and/or environmental variation are associated with cholesterol variability. Grandparents in the three pedigrees that were segregating at the major locus had the highest rates of death due to coronary heart disease. This study establishes that the mixed model has the potential to identify pedigrees with different genetic etiologies for variability in quantitative traits.
In an open access screening campaign for hypertension lasting six weeks 6259 individuals were screened with a Vita-Stat blood pressure computer and an estimated 4.2% to 5.4% of new cases were detected.
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Punctate keratoderma and spastic paralysis occurred in three generations of a family. Several members had keratoderma of the palms and soles or spastic paralysis or both. The family history was consistent with autosomal-dominant inheritance. The age at onset and the rate of progression of symptoms were variable. The concurrence of these lesions can be interpreted to mean either that the keratoderma and the paraplegia are the pleiotropic effects of the same mutant gene or, less likely, that they are the manifestations of two different autosomal mutations segregating in this family. We are not aware of a similar syndrome having been previously reported.
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We have examined recent claims that neuromuscular synapse elimination occurs preferentially among motoneurones from the more rostral of the two spinal roots contributing to the soleus muscle of the rat. The number of synapses made by individual motoneurones contributing to the soleus muscles of the rabbit and rat were estimated at different stages of post-natal development. The assay was based on measurements of twitch tensions in response to stimulation of individual motor axons in ventral root filaments. Contrary to the previous claims, we found that synapses were lost by motoneurones passing through all contributing spinal roots in both the rabbit and rat. Furthermore, in both species there was little or no difference in the extent of synapse elimination associated with the various spinal roots.
Women patients admitted to a district general hospital with non-gynaecological conditions were offered a cervical smear test. In three years 2296 women were tested. Serious uterine pathology was detected in 13 patients (5.7 per 1000) and significant cytological abnormalities (dyskaryosis of all grades) in 46 (20.0 per 1000). Of the women screened 963 (41.9%) had never had a smear test before and 1608 (70.0%) were over 39 yr. The results show that cervical screening of non-gynaecological patients in hospital reaches many of the women at risk for cervical cancer who do not otherwise have smears taken and reveals considerable uterine pathology.
The distribution of risk factors and the prevalence of coronary heart disease (CHD) were studied in 850 first- and second-degree relatives of 98 healthy index cases selected from 3666 school children surveyed for lipid levels in Rochester, Minnesota. Three groups of families were based on an index child's total plasma cholesterol level: 18 families with a child in less than the fifth percentile (low-cholesterol group), 47 with a child in the fifth to ninety-fifth percentiles (middle-cholesterol group) and 33 with a child in greater than the ninety-fifth percentile (high-cholesterol group). The children's cholesterol levels clustered with those of their relatives; mortality due to CHD before age 65 was increased by 2.5 times in grandfathers of index cases in the high-cholesterol group compared with those of the middle-cholesterol group (p less than 0.016). The prevalence of CHD in all the grandfathers was associated with an index child's total cholesterol, more strongly associated with an index child's low-density lipoprotein cholesterol level and most strongly associated with an index child's high-density lipoprotein cholesterol level as a fraction of total cholesterol. This study establishes that childhood lipid and lipoprotein levels from a single cross-sectional survey identify families at elevated risk for CHD.
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To evaluate the roles of alcohol and genetic factors in hepatic iron overload, we studied prospectively 61 patients selected solely on the basis of increased stainable hepatic iron (grade 3 or 4). Independent comparisons were made between alcoholic (n = 20) and nonalcoholic (n = 41) patients, and between patients wih affected relatives (n = 25) and those without (n = 36). For the entire group, the mean value for mobilizable iron was 19.6 g and the prevalence of HLA-A3 was 69.6%, both findings compatible with genetic hemochromatosis. Subgroups were no different in clinical features (diabetes, pigmentation, cardiomyopathy, hypogonadism, or arthropaty), histologic findings (fat, inflammation, fibrosis), indexes of iron metabolism (serum iron, transferrin saturation, chelatable iron, and mobilizable iron stores), or frequency of HLA-A3 and HLA-B7. The only exception was that mean hepatic iron concentration was lower in alcoholic patients than in nonalcoholic patients (17,344 vs. 28,553 micrograms/g dry wt, p less than 0.001). Similarity between subgroups in almost all parameters examined is consistent with the hypothesis that heavy deposition of hepatic iron, as observed in our patients, is an indication of genetic hemochromatosis, regardless of alcohol consumption or the findings of affected relatives. The lower concentrations of hepatic iron in alcoholic patients, despite equal body stores in both groups, suggest that alcohol may alter the distribution of storage iron in genetic hemochromatosis.