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Biomedical subjects

L Williams

Publications and source records attributed to L Williams.

At least 271 records · Page 15Linked to original sources
PubMed1987

A review of liver transplantation for gastroenterologists.

The 1980s will be remembered as the era of transplantation. During this period both liver and heart transplantation have their places as established therapeutic procedures for selected patients with end stage organ failure. As increasing numbers of patients are transplanted, others practicing physicians, especially gastroenterologists and cardiologists, will need to become familiar with all aspects in the care of patients that they have referred for transplantation. Only through close cooperation between transplant surgeons and this new breed of "transplant internists" will all suitable patients be referred for these life-saving procedures and receive appropriate follow-up care.

Adult↗
PubMed1987

Renal-metabolic consequences of antihypertensive therapy with diltiazem versus hydrochlorothiazide.

Twenty-seven patients with mild to moderate essential hypertension were randomized to receive therapy with either hydrochlorothiazide or diltiazem. After a placebo run-in period of 2 weeks, patients received increasing doses of either drug for 14 weeks. Those in whom hypertension was effectively controlled continued for 26 weeks of total treatment. Those not controlled, i.e. blood pressure greater than 140/90 mm Hg or less than 10 mm Hg reduction of pressure, were unblinded and crossed over to therapy with both drugs. Eleven of 14 patients (79%) were effectively treated with diltiazem alone, and 8 of 13 patients (62%) were effectively treated with hydrochlorothiazide alone. Supine blood pressures fell from 152 +/- 5/97 +/- 1 to 142 +/- 4/87 +/- 3 mm Hg in the 11 patients treated with diltiazem, from 152 +/- 2/99 +/- 1 to 134 +/- 3/88 +/- 2 mm Hg in the 8 patients treated with hydrochlorothiazide, and from 151 +/- 4/104 +/- 3 to 140 +/- 5/92 +/- 1 mm Hg in the 8 patients who received both drugs (p less than 0.01 for each group). Diltiazem patients had significant increases in alkaline phosphatase and urinary magnesium. Hydrochlorothiazide patients had increases in serum uric acid, serum globulin, CO2 content, and plasma renin activity. Serum potassium, serum chloride, urinary osmolality, and urinary calcium decreased after treatment with hydrochlorothiazide. Patients receiving both drugs had increases in serum glucose, serum BUN, serum uric acid, serum globulin, and CO2 content. These patients had decreased serum chloride and urinary calcium. Diltiazem monotherapy was comparable to hydrochlorothiazide in efficacy of lowering blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Antihypertensive Agents↗
PubMed1986

Dual trophic effects of the alpha 1-adrenergic receptor in cultured neonatal rat heart muscle cells.

The molecular signals regulating myocardial hypertrophy are unknown. We used a new model system to study this problem. Muscle cells from the neonatal rat ventricle were cultured in serum-free medium. Control cells did not change in size over time and did not show spontaneous contractile activity. Incubation with norepinephrine or epinephrine had two major trophic effects that developed over 1-2 days. The first was stimulation of muscle cell hypertrophy or increase in size. The second was induction of spontaneous contractile activity. The hypertrophic response was mediated through an alpha 1-adrenoceptor. The beating response required both alpha 1- and beta 1-adrenergic receptor stimulation. Alpha 1 stimulation alone produced enlarged cells that did not beat. Alpha 1 plus beta 1 stimulation induced contractile activity even when protein synthesis and hypertrophy were inhibited. Thus, the two alpha 1 responses could be dissociated, providing evidence for two independently-regulated cellular pathways for the dual alpha 1 trophic effects. One pathway leads to hypertrophy. The other, which requires concomitant beta 1 stimulation, controls the development of beating. Preliminary work raises the possibility that different products of inositol phospholipid hydrolysis might initiate the two alpha 1 trophic pathways. Other preliminary work suggests that the growth pathway is associated with the expression of specific genes and might reflect an action of the alpha 1-adrenoceptor on the cell nucleus. These studies define previously unsuspected trophic roles for the alpha 1-adrenergic receptor.

Animals↗
PubMed1986

Partner preferences in different aged female rhesus macaques (Macaca mulatta).

It has been suggested that there is a strong age-peer preference for social partners among aged human and nonhuman primates. The purpose of this investigation was to study the social pairings that occurred in a large (70 animal) social group of rhesus macaques. Six females in each of three age classifications (old, prime, and young adults) were observed during a breeding season and nonbreeding season to determine with whom these individuals interacted in socially affiliative ways. The study group was housed in a 38 X 38 m outdoor area and only naturally occurring interactions were observed. The results suggest strong cross-age partner preferences that affect the distribution of socially affiliative responses within the group. There was a strong preference for kin in all classes except prime aged sisters. Among nonkin only the infants were consistently preferred as target animals for socially affiliative responses.

Aging↗
PubMed1986

Effect of hypoxia on ventilatory and arousal responses to CO2 during NREM sleep with and without flurazepam in young adults.

We examined the ventilatory response to CO2 at two levels of oxygenation during wakefulness and sleep in healthy young adults before and after the ingestion of a single dose of 30 mg flurazepam. Progressive hypercapnia was produced at two levels of arterial O2 saturation (greater than 99 and 87%) by having subjects re-breathe from a tight-fitting face mask and a reservoir bag containing gas mixtures with two different O2 concentrations. Ventilation was measured with an inductive plethysmograph. O2 saturation was measured with an ear oximeter. Sleep was monitored using standard techniques by recording the electroencephalogram, eye movements, and chin electromyogram. During wakefulness, hypoxia increased the slope of the ventilatory response to CO2 and shifted the response slightly to the left. NREM sleep lowered the slope of the CO2 response under both hyperoxic and hypoxic conditions. The slope of the hyperoxic CO2 response curve was not affected by flurazepam during wakefulness or sleep. After administration of flurazepam to the subjects, the shift of the CO2 response curve to the left produced by hypoxia (additive effect) during NREM sleep was slightly less as compared to control, but hypoxia still increased the slope of the CO2 ventilatory response. During hypoxic hypercapnia, the PCO2 at arousal from sleep was significantly lower than during hyperoxic hypercapnia, but the level of ventilation at arousal during hypercapnia was similar in the control condition and after flurazepam. We conclude that (a) both natural and flurazepam-induced sleep depress ventilatory responses to hyperoxic and hypoxic hypercapnia and alter, in a complex fashion, the effects of hypoxia and hypercapnia on ventilation; and (b) hypoxia and hypercapnia interact as arousal stimuli in both natural and flurazepam-induced sleep.

Adult↗
PubMed1986

Hepatocellular adenoma and nodular regenerative hyperplasia of the liver in a young man.

A 26-year-old man had a massive intraabdominal hemorrhage from a hepatocellular adenoma (HCA). The tumor arose within a liver that demonstrated generalized nodular regenerative hyperplasia. The patient had no factors predisposing to either HCA or nodular regenerative hyperplasia (NRH) of the liver. Although rare, HCA should be included in the differential diagnosis of spontaneous intraperitoneal hemorrhage even in young men. The coexistence of HCA and NRH of the liver in this patient may indicate a common pathogenesis.

Adult↗
PubMed1986

DNA polymorphic haplotypes on the short arm of chromosome 11 and the inheritance of type I diabetes mellitus.

The linked polymorphic loci 5' to the insulin gene and 3' to the c-Harvey-ras-1 (c-Ha-ras) gene, both localised to the short arm of chromosome 11, have been studied in 14 type I diabetic pedigrees. The use of a cloned gene probe corresponding to the polymorphic locus adjacent to the insulin gene, in combination with the restriction endonuclease PvuII, has permitted an improvement in the resolution of sizes of insert at this locus. An MspI restriction fragment length polymorphism at the c-Ha-ras proto-oncogene locus (4 cM upstream from the insulin gene) was used to identify parental insulin gene related alleles unambiguously, and subsequently a pedigree analysis was performed to determine whether subclasses of inserts at this locus track with insulin dependent diabetes. Segregation analysis demonstrated no linkage between the polymorphic loci 5' to the insulin gene, nor 3' to the c-Ha-ras, and type I diabetes. However, a similar analysis confirmed an association between the HLA locus chromosome 6 and insulin dependent diabetes.

Adolescent↗
PubMed1986

PR crisis control.

Explore the source record for details and available documents.

Communication↗
PubMed1986

Evaluation of the pediatric patient for liver transplantation.

In a 36-month period from 1981 to 1984, 209 pediatric patients were evaluated for liver transplantation. The purpose of the evaluation was to assess the severity and progression of the disease, anatomical suitability for transplantation, and psychosocial stability and to initiate family education. Of the 209 patients evaluated, 85 (41%) underwent transplantations and 64 (75%) survived at least 12 months. Thirty-four (16%) patients were not considered candidates for transplantation. The mean waiting period increased from 80.3 days to 232 days. Of 174 patients considered for transplantation, 41 (24%) died prior to surgery. A formal evaluation for liver transplantation permitted appropriate selection of candidates and provided education for informed consent. We also stress the need for greater participation in pediatric organ donation.

Adolescent↗
PubMed1985

Sequence organisation of rat seminal vesicle F gene: location of transcriptional start point and sequence comparison with six other androgen-regulated genes.

Seminal vesicle F gene, encoding an androgen-regulated serine-rich structural protein of the rat copulatory plug, has been sequenced together with 5' and 3' flanking regions. The intron/exon arrangement of the gene deduced from restriction maps was confirmed. The major and possible minor transcriptional start points were located by primer extension analysis and S1 nuclease mapping. A published nucleotide sequence for seminal vesicle S gene which also encodes an androgen-regulated protein of the copulatory plug has been extended to allow comparison of F and S genes. The considerable sequence homology between the two genes confirms their evolutionary relatedness. Homology is especially high in their promoter regions and their transcriptional start points are identical. They share several regions of dyad symmetry including one just upstream of the promoter. The upstream regions of F and S genes were compared with those of five other androgen-responsive rodent genes in an attempt to identify common sequence motifs that might be involved in hormonal regulation of gene expression.

Animals↗
PubMed1985

An ultrastructural study of meconium corpuscles in human foetal colon.

In human foetal colon meconium corpuscles were observed in the colonic epithelium during the stage of secondary lumina development and enlargement. Transmission electron microscopy of these specimens revealed inclusion bodies in the superficial and deeper layers of the epithelium. Many of the membrane-bounded inclusion bodies contained well-preserved organelles and some inclusions contained nuclear fragments. There was evidence of nuclear fragmentation with condensed chromatin arranged in crescentic caps. The ultrastructural observations are typical of apoptosis, a mode of cell death first described in 1972 by Kerr and colleagues. Thus, meconium corpuscles are apoptotic bodies found as a result of the deletion of healthy normal cells during the reshaping and development of organs.

Colon↗