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Biomedical subjects

J Johnson

Publications and source records attributed to J Johnson.

At least 667 records · Page 37Linked to original sources
PubMed1981

Histocompatibility antigens in black patients with essential hypertension.

Essential hypertension is a common disorder with potentially life-threatening sequelae. Hypertension among black persons may have characteristics different from hypertension among white persons. It has been estimated that up to 60% of population variance in blood pressure may be attributable to genetic differences. We studied the distribution of HLA antigens in 100 black hypertensives and 100 normotensive controls. Hypertension was not significantly associated with any of the 25 HLA antigens identified. We conclude that HLA-A and HLA-B locus antigens are not associated with essential hypertension in the black patient.

Adult↗
PubMed1981

Enflurane analgesia in obstetrics.

The effects of enflurane analgesia (approximately 0.5%) were studied in 55 patients during the second stage of normal vaginal delivery and were compared with effects of nitrous oxide (approximately 40%) in 50 similar patients. The enflurane and oxygen mixture was rated satisfactory by 89% of the mothers and 80% of the anesthesiologists. These ratings did not differ significantly from those for nitrous oxide. Obstetricians, however, rated the enflurane and oxygen mixture superior. The newborns of mothers receiving both agents wee vigorous and comparable when assessed by Apgar scores and cord blood gas tensions. The estimate of blood loss was similar in both groups. Serum inorganic fluoride concentrations in the mother after anesthesia were not significantly increased from preanesthetic levels with either agent. There was no biochemical evidence of renal toxicity. In neonates of mothers given enflurane, the mean umbilical cord concentration of serum inorganic fluoride ions was 2.4 +/- 0.2 micromoles/L, a value well below that associated with nephrotoxicity.

Adult↗
PubMed1980

Stabilization of atlantoaxial subluxation in the dog, using the nuchal ligament.

A technique for the stabilization of atlantoaxial subluxation in the dog was developed. The technique involved use of the nuchal ligament as a means of securing the spinous process of the axis to the dorsal arch of the atlas. Two cases were typical atlantoaxial subluxation in toy-breed dogs, and 2 cases were traumatic subluxation secondary to fracture of the axis in dogs of large breeds. On the basis of the results in these cases, it was concluded that the technique has advantages over techniques in which wire or nonmetallic suture material is utilized for stabilization.

Animals↗
PubMed1980

Inactivation of yeast glucose-6-P dehydrogenase by aspirin.

Glucose-6-P dehydrogenase is irreversibly inactivated by treatment with Na salts of aspirin. Kinetic data show that 1 molecule of aspirin reacts with each active unit when the enzyme is inactivated. The rate of inactivation is enhanced with increasing pH but is reduced in the presence of glucose-6-P or NADP+. Na salicylate fails to inactivate the enzyme.

Aspirin↗
PubMed1980

Beta-chain contact sites in the haemoglobin S polymer.

The amino acid residues involved in the areas of contact that stabilise the haemoglobin S polymer fibre seem to be the same ones that stabilise the basic unit of the deoxyhaemoglobin S crystal: the Wishner-Love double strand. The haemoglobin S fibre is probably formed by a unique packing of these double strands.

Binding Sites↗
PubMed1980

Mutations within an intron and its flanking sites: patterns of novel polypeptides generated by mutants in one segment of the cob-box region of yeast mitochondrial DNA.

We have undertaken a systematic examination of the polypeptides accumulating in thirteen (out of 23) mutants in the intron cluster box7 and its flanking clusters box2 and box9 of the cob-box (cytochrome b) region of the mitochondrial genome of Saccharomyces cerevisiae. We have subjected these polypeptides to fingerprint analysis, both sequential and in parallel, with two proteases in order to disclose sequence homologies and differences between the different novel polypeptides themselves, and between them and the wild type product of the gene, i.e. apocytochrome b. One of our aims has been to establish the existence of possible correlations between the nature of the novel polypeptides and the fine structure genetic map of that segment of the mitochondrial genome. Our results show that all box7 mutants accumulate the following set of polypeptides not seen in wild type cells: a) a characteristic set of "large" polypeptides consisting of three species: p56, p42 and p35 or p34.5; b) a polypeptides p23; c) a much shorter fragment (of which the apparent molecular weight varies from 12.5 to 13, according to the mutation) with the exception of two mutants; d) in addition, the majority accumulate in varying amounts a polypeptide p30 closely related to but not identical with apocytochrome b. Moreover only two box7 mutants accumulate a polypeptide in the range of mobilities corresponding to 25-27 Kd (referred to as class p26) while such a polypeptide is seen in all box9 and box2 mutants examined with one exception in box2.

Amino Acids↗
PubMed1980

Differential lipemic and proteinemic response to oral ethinyl estradiol and parenteral estradiol cypionate.

Oral synthetic estrogen administration to normal women has been shown to result in both a lipemic and a proteinemic response. To determine whether parenteral estrogen administration would have similar results, the effects of intramuscular depo-estradiol cypionate on serum lipids and ceruloplasmin were examined. The oral and parenteral estrogens chosen for this study are frequently used therapeutically and varying doses in the range of those commonly employed clinically were given to the experimental subjects. Following oral ethinyl estradiol (20, 50, and 100 micrograms every 12 hr) comparable and significant increases in triglyceride (73 +/- 6 to 128 +/- 10 mg/dl, p < .001), ceruloplasmin (87 +/- 4 to 188 +/- 11 mg/dl, p < .001), and HDL-cholesterol (60 +/- 2 to 74 +/- 3 mg/dl, p < .001) were observed. In contrast, despite substantial increases in serum estrogens, parenteral estrogen administration (depo-estradiol cypionate, 5 and 10 mg) failed to result in alterations in any of the measured parameters. Thus, the route and/or type of estrogen administered may determine the proteinemic and lipemic effects of estrogen in man.

Administration, Oral↗
PubMed1980

Linkage analyses of murine immunoglobulin heavy chain and serum prealbumin genes establish their location on chromosome 12 proximal to the T (5;12) 31H breakpoint in band 12F1.

Analysis of backcross mice carrying the Harwell translocation T(5;12)31H has led to the definitive localization of the immunoglobulin heavy chain gene cluster. Both Igh-1 and Pre-1 loci were found to segregate in tight linkage with the chromosomal markers 5(12) and 12(5), which define the balanced translocation T(5;12)31H. Additional data establish the location of these genes at the telomeric end of chromosome 12. That both loci are proximal to the chromosomal breakpoint in band 12F1 is shown by the phenotypes of segregants aneuploid for the presence or absence of the small marker 5(12). The order of loci inferred from a single recovered recombinant is: centromere-Igh-1-Pre-1-T(5;12)31H.

Animals↗
PubMed1980

Primary peptic ulcerations of the jejunum associated with islet cell tumors. Twenty-five-year appraisal.

A review of 42 patients with gastrinoma, who either survived five years or longer or who died during this period of evaluation, was carried out to define the surgical principles which might be combined with the recent trend toward cimetidine therapy. Thirty-four (80%) of the patients had total gastrectomy with an operative mortality rate of 2.3%, and eight patients (20%) had less than total gastrectomy. No tumor was found in six patients with hypergastrinemia and an abnormal secretin bolus whose five-year survival rate was 100%. Of the thirty-six patients having tissue proof of gastrinoma, twenty-two (61%) had complete resection of all gross tumor resulting in a 76% five-year survival rate. Fourteen patients had unresectable tumor or partial resection with a five-year survival rate of 21%. Complete gross tumor resection increased mean survival by six years (p < 0.01), but resulted in persistent eugastrinemia in only two patients. Long-term survival was possible with a combination of vagotomy, lesser gastric procedures, tumor resection, and cimetidine, seven of eight patients living more than five years. Surgical management of gastrinoma should be directed toward aggressive tumor resection and vagotomy, with reliance on cimetidine therapy postoperatively to control the gastric hypersecretion. Total gastrectomy should be reserved for cimetidine failures and those who do not wish to take cimetidine for the rest of their lives.

Adenoma, Islet Cell↗
PubMed1980

Thyrotropin-releasing hormone provokes abnormal follicle-stimulating hormone (FSH) and luteinizing hormone responses in men who have pituitary adenomas and FSH hypersecretion.

Serum FSH ad LH concentrations after the administration of TRH were measured in 10 men who had pituitary adenomas associated with FSH hypersecretion. Similar measurements were made in 12 men who had pituitary adenomas but no FSH hypersecretion, in 10 age-matched, normal men, and in 5 men who had primary hypergonadism. The mean serum LH concentration in the men who had pituitary adenomas and FSH hypersecretion increased 136% after TRH administration, significantly greataer (P < 0.005) than the 48% increase in the normal men or the 51% increase in the men who had pituitary adenomas without FSH hypersecretion. Serum LH did not increase at all in the men who had primary hypoganadism. The serum FSH concentration did not increase in any of the normal men, in the men who had pituitary adenomas without FSH hypersecretion, or in the men who had primary hypogonadism, but did increase in 5 of the 10 men who had FSH hypersecretion; the mean increase in these 5 men was 38%. The exaggerated LH responses and the nonspecific FSH responses to TRH of the men who had pituitary adenomas associated with FSH hypersecretion suggest that control of both FSH and LH secretion by these adenomas is abnormal and, therefore, that these adenomas are likely gonadotroph cell adenomas.

Adenoma↗
PubMed1980

Fast neutron teletherapy for advanced carcinoma of hypopharynx and supraglottic larynx.

The results of a Phase I clinical trial using fast neutron teletherapy for advanced squamous cell carcinoma of the hypopharynx and supraglottic larynx are reported. Ten patients with hypopharyngeal tumors were treated for cure using neutrons alone and 6 patients with hypopharyngeal tumors were treated for cure using a combination of neutrons and photons as part of a mixed beam fraction scheme. In the neutron-only group, the initial complete remission rate was 4/10 (40%). The mean survival of this group of patients with initial complete remission was only 5.75 months (range 2--10) but all patients died without evidence of recurrent tumor at the primary site. In the mixed beam group, the initial complete remission rate was 5/6 (83%) but the local control rate dropped rapidly to 41 per cent when displayed on an actuarial plot. Six patients with advanced tumors of the supraglottic larynx were treated for cure, 5 with neutrons alone and one with a mixed beam regime. The initial complete remission rate was 3/6 (50%) but 2 of these patients rapidly recurred, which reduced the local control rate on an actuarial plot to 16 per cent. The relative adverse effects of the neutron-only treatment regime appear to be substantially greater than those of the mixed beam treatment regime.

Clinical Trials as Topic↗
PubMed1980

Eimeria tenella: clinical effects in partially immune and susceptible chickens.

Chickens made partially immune to E. tenella infection exhibited cecal lesions after challenge. Some of the chickens had cecal lesions of severity similar to those of birds having their first infection with the parasite. The presence of severe cecal lesions in the partially resistant birds was not accompanied by lowered body weight gain or packed erythrocyte volumes and prothrombin time was not extended. It is suggested that there are at least three stages of immunity to E. tenella; birds may be totally resistant to parasite and no development occurs, birds may be resistant to a degree where oocysts are discharged after challenge but no lesions occur, or birds may be resistant to the clinical effects of the disease despite having severe lesions.

Animals↗