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H Gordon

Publications and source records attributed to H Gordon.

At least 19 recordsLinked to original sources
PubMed1992

Cooperation between the products of different nuclei in hybrid myotubes produces localized acetylcholine receptor clusters.

Cultured myotubes form clusters of acetylcholine receptors (AChRs) spontaneously and at sites of nerve-muscle contact. To investigate the cellular mechanisms by which spontaneous clusters are formed, we have made hybrid myotubes between a mouse muscle cell variant, S27, that does not cluster AChRs, and one that does not make AChRs. We have also made hybrid myotubes using S27 and quail muscle cells. In both cases, clusters of AChRs were found near the non-S27 nuclei; in the case of the interspecific hybrids, mouse AChRs were associated with extracellular matrix components contributed by the quail nuclei. Our results suggest that AChRs made by one nucleus can be clustered by localized extracellular matrix produced by a different nucleus and provide an example of nuclear cooperation between the products of different nuclei within multinucleated muscle fibers.

Animals↗
PubMed1992

Retrospective maternal mortality case ascertainment in West Virginia, 1985 to 1989.

OBJECTIVE: The death of women from pregnancy-related causes remains a threat to national maternal and child health. Maternal deaths as persistent, albeit rare occurrences are overlooked if vital registration systems are relied on to report such deaths. STUDY DESIGN: Live birth records were matched with death records for women of reproductive age to detect if a woman died within 1 year of delivery. The data for potential cases were reviewed by committee and classified as maternal and nonmaternal deaths. RESULTS: Of all linked birth-death records, 32% were related to pregnancy: 81% were directly related to pregnancy and 19% were indirectly related to pregnancy. The most frequent causes of death were hemorrhage and embolism. Thirty-eight percent of the women were transferred to tertiary hospitals before death. The case ascertainment through this study improved maternal death detection by 100% over official vital statistics. CONCLUSION: Enhanced maternal mortality surveillance increased the detection of maternal death in West Virginia. Case review of these deaths yielded important information useful in shaping the state's perinatal system.

Adult↗
PubMed1992

Prelabour rupture of the membranes at term and unfavourable cervix; a randomized placebo-controlled trial on early intervention with intravaginal prostaglandin E2 gel.

Fifty nine women with prelabour rupture of membranes, unfavourable cervix and no evidence of infection or fetal distress were randomized formally to receive prostaglandin E2 (3mg) gel or sterile K-Y Jelly intravaginally. Conservative expectant management was followed for the next 24 hours. The subsequent management of the labour followed departmental protocol. The women who received prostaglandin went into labour sooner and were delivered earlier but the duration of labour was not significantly different. There were no significant differences in other clinical outcomes. There was 1 case of uterine rupture in the prostaglandin group. We conclude that early intervention with prostaglandin E2 gel intravaginally confers no advantage compared with conservative management except for earlier confinement in this group of patients.

Administration, Intravaginal↗
PubMed1992

Chlamydia trachomatis antigen prevalence among pregnant women in West Virginia.

During 1990, more than 2,100 women who received prenatal care at one of four clinics which serve 11 West Virginia counties, were screened for chlamydial antigen. Overall, 5.6 percent of the women screened had positive antigen tests and 90 percent of these individuals were under the age of 25. The prevalence of chlamydia was different at three geographic sites with the highest rate of positive antigen test being 9.4 percent at one site. These findings led to a careful analysis of the prevalence of this disease among women who lived in rural areas versus those who lived in urban areas. This detailed analysis involved only patients seen in the Grafton and Morgantown clinics, and revealed a tendency for most positive antigen tests to occur among women with urban addresses. Our study indicates that a substantial chlamydial problem exists among pregnant women of young age. Although screening all pregnant women for chlamydia may not be cost effective, knowing which individuals are at highest risk may help target limited screening for these patients.

Adult↗
PubMed1991

Spontaneous carotid-cavernous fistulae in Ehlers-Danlos syndrome Type IV. Case report.

Spontaneous bilateral carotid-cavernous fistulae and cervical artery dissection is reported in a 20-year-old woman with Ehlers-Danlos syndrome Type IV. The clinical features of 16 previously published cases of spontaneous carotid-cavernous fistulae associated with Ehlers-Danlos syndrome Type IV are reviewed, for a total of 17 cases. The mean age of the 14 women and three men was 31.6 years. Only direct fistulae were encountered. Diagnostic neuroangiography carried morbidity and mortality rates of 36% and 12%, respectively; neuroradiological treatment resulted in death in one of six patients. The possible value of desmopressin in the management of these patients is discussed. In view of the risks of arterial puncture and surgery, the authors emphasize the importance of early recognition of Ehlers-Danlos syndrome.

Adult↗
PubMed1990

Negative control of the helix-loop-helix family of myogenic regulators in the NFB mutant.

We have characterized a nondifferentiating mouse muscle cell line, NFB, that represses the activity of the helix-loop-helix (HLH) family of myogenic regulators, yet expresses sarcomeric actins. The NFB MyoD gene is silent, but can be activated upon transfection of a long terminal region-controlled chicken MyoD cDNA, resulting in myogenesis. When NFB cells are fused with H9c2 rat muscle cells in heterokaryons, the level of rat MyoD transcripts declines. Thus, the stoichiometry of MyoD and the putative repressor controls myogenesis. Although NFB cells express myogenin and Myf-5 transcripts, the activity of these regulators is also repressed:myogenesis is not induced in 10T1/2 fibroblasts and is repressed in L6 muscle cells upon fusion with NFB cells. We conclude that the myogenic HLH regulators are not required for sarcomeric actin gene activation and that myogenesis is subject to dominant-negative control.

Actins↗
PubMed1990

Frequency of congenital heart defects in patients with hemophilia.

Most structural congenital heart defects (CHD) are thought to be multifactorially determined, but the precise causal factors usually are unknown. One may postulate that vascular events, such as hemorrhage in the developing embryo, could influence morphogenesis of the heart. One method of studying this hypothesis is to determine the frequency of CHD in persons with heritable bleeding diatheses and their families. We reviewed retrospectively medical and family histories of 120 hemophilia A and 14 hemophilia B patients seen in our Genetics Department. The family histories included 1,126 maternal relatives of hemophiliac patients. We also reviewed the family histories of 138 patients with X-linked disorders who did not have bleeding diatheses or syndromes associated with CHD; these histories included 960 maternal relatives. There was one confirmed case of a CHD in 134 hemophilia patients, giving a frequency of 0.75% compared to 0.8% in the general population at birth. There was no apparent difference in the frequency of CHD in hemophilia A and B patients compared to the general population or in the relatives of hemophilia patients as compared to control individuals.

Female↗
PubMed1990

Synaptic dynamics at the neuromuscular junction: mechanisms and models.

During development, the neuromuscular junction passes through a stage of extensive polyinnervation followed by a period of wholesale synapse elimination. In this report we discuss mechanisms and interactions that could mediate many of the key aspects of these important developmental events. Our emphasis is on (1) establishing an overall conceptual framework within which the role of many distinct cellular interactions and molecular factors can be evaluated, and (2) generating computer simulations that systematically test the adequacy of different models in accounting for a wide range of biological data. Our analysis indicates that several relatively simple mechanisms are each capable of explaining a variety of experimental observations. On the other hand, no one mechanism can account for the full spectrum of experimental results. Thus, it is important to consider models that are based on interactions among multiple mechanisms. A potentially powerful combination is one based on (1) a scaffold within the basal lamina or in the postsynaptic membrane which is induced by nerve terminals and which serves to stabilize terminals by a positive feedback mechanism; (2) a sprouting factor whose release by muscle fibers is down-regulated by activity and perhaps other factors; and (3) an intrinsic tendency of motor neurons to withdraw some connections while allowing others to grow.

Animals↗
PubMed1990

Induction of labour postdates in primiparae using vaginal prostaglandin tablets.

The management of pregnancy after 40 completed weeks remains controversial because induction of labour has been, in the past, associated with an increase in the incidence of caesarean section. This study examined the use of vaginal prostaglandin tablets for the induction of labour in selected primiparae after forty one weeks of pregnancy. The outcome of prostaglandin induction in 118 consecutive patients was compared with the outcome in 90 consecutive patients who went into labour spontaneously at the same gestation before induction could be undertaken. The active management of labour was applied in both groups and, therefore, the management of labour was strictly standardised. There was no difference between the two groups in the mode of delivery. Nor was prostaglandin induction associated with an increased incidence of prolonged labour. In selected primiparae, the cautious use of vaginal prostaglandin tablets can induce labour successfully postdates without increasing the complications of labour. A larger study is required to examine the effects of the induction of labour at this gestation on the fetal outcome.

Administration, Intravaginal↗
PubMed1990

A specific effect of muscle cells on the distribution of presynaptic proteins in neurites and its absence in a C2 muscle cell variant.

The distribution of neurofilament (NF) and synaptic vesicle (SV) proteins in neurites cultured in vitro was visualized with immunocytochemical methods. NF and SV proteins were detected in neurites from both embryonic mouse spinal cord and chick ciliary ganglion neurons. NF proteins generally occupied more proximal, unbranched neurite segments while SV proteins were most often found in highly branched terminal segments. Neurites from mouse spinal cord cells showed a striking segregation of the NF and SV proteins into distinct domains; neurites from chick ciliary ganglion cells exhibited a similar, though less pronounced segregation. In cocultures of neurons and muscle cells, the neurite segments in contact with myotubes more often stained for SV than for NF while the opposite was true for neurites not in contact with myotubes. The preferential association of SV neurites with myotubes was also observed when the myotubes were previously fixed with paraformaldehyde. This association was absent in neurites growing over Chinese hamster ovary cells, suggesting that the effect is specific for muscle cells. Coculture of neurons with variant strains of C2 myotubes that are deficient in AChR (1R-) or proteoglycans (S27) revealed a preferential association of SV neurites with 1R- myotubes but not with S27 myotubes. Thus, proteoglycans on the surface of C2 myotubes may influence the growth and/or differentiation of presynaptic neurons.

Animals↗
PubMed1990

Twin pregnancy complicated by single intrauterine death. Problems and outcome with conservative management.

During an 11-year period we encountered 16 pregnancies in which one twin died in utero and the pregnancy continued. Eight of these twin pregnancies were monochorionic. None of the women developed severe disseminated intravascular coagulation. The fetal outcome indicates that the prognosis for a surviving dichorionic twin is relatively good, with immaturity the main hazard. By contrast the surviving monochorionic twin has a poor prognosis with a high frequency of neurological damage. This damage is not related to intrapartum or neonatal problems and at present cannot be diagnosed before birth. There is no evidence that birth of the surviving twin by caesarean section will improve the prognosis. Early diagnosis of monochorionic twins and subsequent ultrasound follow up should identify fetal growth discrepancy and possible twin to twin transfusion requiring early delivery.

Female↗
PubMed1990

Pachyonychia congenita: a clinical study of 12 cases and review of the literature.

Twelve cases of pachyonychia congenita were reviewed. The mode of inheritance was autosomal dominant. The clinical features of these patients included thickened nails, hyperkeratosis of the palms and soles, thinning of hair or alopecia, painful bullae or ulcerations of the palms and soles, leukokeratosis oris, verrucous lesions of the extremities, hyperhidrosis, premature eruption of teeth, paronychial infections, epidermal cysts with milia, and corneal dyskeratosis at times associated with cataracts. Biopsy from the plantar lesions usually revealed marked hyperkeratosis, acanthosis, moderate hypergranulosis, and minimal dermal inflammatory infiltration. Treatment with keratolytic agents and lubricants is indicated to areas of palmar and plantar hyperkeratosis but usually produces only transient benefit. Squamous cell carcinoma developed in one of the patients over the site of chronic plantar ulcerations. Areas of chronic bullous formation or ulceration should be observed for possible skin malignancy.

Adolescent↗
PubMed1989

Mesenteric fibromatosis complicating familial adenomatous polyposis: predisposing factors and results of treatment.

Between January 1975 and December 1983, 24 of 183 patients (13%) with familial adenomatous polyposis (FAP) seen at the Mayo Clinic had mesenteric fibromatosis (MF). MF was found most often in FAP patients with associated extra-colonic "Gardner" signs (19 patients) and those who had had previous abdominal surgery (20 patients). In 4 patients, MF appeared spontaneously. The male-to-female ratio was 0.4, with a median age of 31 years in women and 37 years in men. Ten of 24 patients (42%) had been asymptomatic prior to diagnosis at time of surgery for FAP. Complications of the disease included intestinal or urinary tract obstruction. Minimal surgical manipulation seemed to be associated with fewer postoperative complications and a lesser risk of regrowth of the tumor. Nonsurgical treatment, including tamoxifen and sulindac in combination, may be beneficial. Surgery should be reserved for relief of obstruction, and bypass is preferred to resection.

Adenomatous Polyposis Coli↗
PubMed1989

Glycosaminoglycan variants in the C2 muscle cell line.

Using a replica technique, we have isolated and characterized five genetic variants of the C2 mouse muscle cell line that are defective in incorporation of radiolabeled sulfate into glycosaminoglycans (GAGs). The variants incorporate free sulfate into GAGs at 5-20% of wild-type levels. None of the variants is defective in sulfate transport across the cell membrane, and in no case could the deficit in incorporation of sulfate be reversed by addition of an artificial initiator of GAG biosynthesis, p-nitrophenyl beta-D-xyloside. Analysis of the incorporation of [3H]glucosamine into GAGs by the variants revealed three different patterns: one variant incorporated [3H]glucosamine at the wild-type level; one, S27, at a severely reduced level; and three at intermediate levels. Four of the five variants showed marked deficits in their ability to differentiate and fuse. The remaining variant, S27, formed multinucleated myotubes and expressed acetylcholine receptor with a normal time course. Differentiation of the first four variants could not be restored by addition of exogenous GAGs or extracellular matrix. Because of the important roles that GAGs and proteoglycans are thought to play in the differentiation of muscle, these genetic variants should serve as useful tools in functional analyses of these molecules.

Animals↗