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Biomedical subjects

W Johnson

Publications and source records attributed to W Johnson.

At least 217 records · Page 12Linked to original sources
PubMed1977

Bacterial growth inhibition by amniotic fluid. VII. The effect of zinc supplementation on bacterial inhibitory activity of amniotic fluids from gestation of 20 weeks.

Twenty human amniotic fluids obtained from gestations of 20 weeks' duration supported bacterial growth. Nine of the 20 fluids could be made inhibitory by adjusting the phosphate to zinc ratios of the fluids to less than 200 mug per milliliter. These fluids contained the phosphate-sensitive bacterial inhibitor previously, but the fluids contained sufficient phosphate to inactivate the antibacterial system. The remaining 11 amniotic fluids did not contain the peptide component of the phosphate-sensitive bacterial inhibitor and could not be made inhibitory by adjusting the phosphate to zinc ratio to less than 200 mug per milliliter. The data obtained suggested synthesis of the peptide component may occur at a gestational age of approximately 20 weeks. The peptide may indirectly be detected in fluids by determining whether antibacterial activity is obtained when the phosphate to zinc ratio of the fluids is adjusted to less than 200 mug per milliliter.

Amniotic Fluid↗
PubMed1977

Effect of swallowed isosorbide dinitrate on blood pressure, heart rate and exercise capacity in patients with coronary artery disease.

Blood pressures and heart rates were measured with the patients supine and standing after a placebo and small (5 to 10 mg) and large (10 to 30 mg) doses of isosorbide dinitrate were given orally in double-blind fashion to six patients. Compared to the findings after the placebo, the blood pressure level fell and the heart rate increased after the ingestion of isosorbide dinitrate. The changes were more striking with the patients standing than with them supine, and the larger dose of the drug produced greater changes than the smaller dose. The hemodynamic effects were usually apparent at 15 minutes, peaked between 30 and 120 minutes, and were still present at 240 minutes. Two hours after swallowing a 7.5 to 20 mg dose of isosorbide dinitrate or placebo, administered in random fashion, 10 patients with coronary artery disease and angina pectoris underwent graded, treadmill, exercise testing designed to provoke angina only after 3 minutes or more. Nine of them exercised longer and achieved higher maximal heart rates after taking the isosorbide dinitrate. Thus, in man, swallowed isosorbide dinitrate has a dose-related, "long-acting," pharmacologic effect, and when tested by properly designed protocols, it improves exercise capacity. However, because the problems of nitrate tolerance and dependence have not been resolved, the place of oral nitrates in the management of patients with angina pectoris remains uncertain.

Administration, Oral↗
PubMed1977

Role of endotoxin contamination in ribiosomal vaccines prepared from Salmonella typhimurium.

Ribosomal vaccines prepared from Salmonella typhimurium SR-11 and 6707 an Re mutant bacterium of strain LT2, were effective immunogens in A/J and C3H/HeDub inbred mice. Only SR-11 ribosomes were able to induce significant protection in C3H/HeJ mice. C57BL/6J mice were not protected by either ribosomal preparation. A/J mice were protected against salmonella infection by purified SR-11 endotoxin preparations. Neither the C3H/HeDub, the C3H/HeJ, nor the C57BL/6J mice were protected by the endotoxin preparation. Passive hemagglutination studies showed that C3H/HeJ mice had no antibodies to O antigen but were significantly protected by SR-11 ribosomes. In contrast, C57BL/6J mice, which had the highest titers of O antibodies of the four inbred mouse strains, were not protected by SR-11 ribosomes. Endotoxin cannot totally account for the effectiveness fo ribosomal account for the effectiveness of ribosomal vaccines prepared from S. typhimurium.

Animals↗
PubMed1977

Focused psychiatric curriculum selection: student, psychiatrist, and nonpsychiatrist physician expectations.

The authors obtained curriculum needs analysis data from second-year medical students and compared these with data obtained from nonpsychiatrist physicians and psychiatrists. All groups felt that interviewing skills, the doctor-patient relationship, managing the dying patient, and evaluation of suicidal patients were important topics. All gave psychological testing, behavior modification, mental retardation, and psychoanalytic theory the lowest teaching priority. The students gave a higher rating to all topics than did the other groups. The authors suggest that this kind of analysis can facilitate curriculum selection and implementation.

Attitude of Health Personnel↗
PubMed1977

The metabolic clearance rate, the brain extraction and distribution and the uterine extraction and retention of progesterone and R 5020 in estrogen-treated ovariectomized rabbits.

The metabolic clearance rate (MCR), uterine extraction, uterine retention and brain distribution of the synthetic progestin R 5020 and progesterone were studied in estrogen-treated ovariectomized rabbits. The MCR of R 5020 was 163+/-15 (SE) 1/day and was lower than that of progesterone. The uterine extraction of R 5020 (51.4+/-3.9 (SE)%) was greater than that of progesterone (33.7+/-7.7%) as was the uterine tissue:arterial blood ratio (28.1+/-4 vs. 7.3). The brain and pituitary retention and distribution of R 5020 and progesterone were the same and provided no evidence for a selective accumulation of a progestin in the pituitary or hypothalamus.

Animals↗
PubMed1977

Delayed wattle reaction as a measure of cell-mediated immunity in the chicken.

The cell-mediated immune (CMI) response to diphtheria toxoid (DT) was studied in commercial broiler breeder lines. The chickens were immunized with DT in complete Freund's adjuvant 21 days before CMI assay by delayed wattle reactivity (DWR) to DT. The DWR was shown to be a valid measure of CMI and to correlate with spleen cell migration inhibition and blastogenesis assays of CMI in vitro. In addition, each criterion of CMI was met, except for the passive transfer of DWR. These criteria were delayed timing, gross morphology, histopathology of DWR, and effect of antilymyphocytic sera on DWR. The duration of DWR over a 1-year period differed in the two lines of chickens tested. A significantly greater DWR was found in one line with all birds remaining reactive for CMI whereas in the other line 16% did not have CMI by the end of the year. The differences may reflect genetic variability within and between lines in expression of CMI.

Animals↗
PubMed1977

Amniotic fluid antibacterial mechanisms: newer concepts.

In this review the factors present in human amniotic fluid that may function to inhibit bacterial growth have been examined. It appears that several potential antibacterial systems are present. Lysozyme and B-lysin may significantly contribute to the killing of gram-positive bacteria. Whether or not the remaining antibacterial systems function to inhibit gram-positive organisms remains to be determined. The phosphate-sensitive bacterial inhibitor recently described in our laboratory may represent the primary defense mechanism against gram-negative bacteria in amniotic fluid. Studies are warranted to ascertain whether this antibacterial system also inhibits gram-positive bacteria. The phosphate-sensitive bacterial inhibitor is quite different from other bacterial inhibitors in at least three respects. The system is very sensitive to the ubiquitous phosphate anion. The reason for this sensitivity is unknown and is difficult to explain phylogenetically, since phosphates are present virtually everywhere. To our knowledge this is the first antibacterial system of human origin which has been shown to require a metal cation as an integral part of the bactericidal effect. The peptide component of the phosphate-sensitive bacterial inhibitor is also unique in that it is of the molecular size of antibiotics or hormones. Additionally, the peptide does not appear to contain any unusual amino acids to explain its antibacterial activity. The mechanism of bacterial destruction of the phosphate-sensitive bacterial inhibitor, and its relation to the other antibacterial systems in amniotic fluid, remain to be elucidated.

Amniotic Fluid↗
PubMed1976

Bacterial growth inhibition by amniotic fluid. V. Phosphate-to-zinc ratio as a predictor of bacterial growth-inhibitory activity.

Human amniotic fluid has been shown to contain an inorganic bacterial growth-inhibitory component, zinc. The average zinc concentration in amniotic fluid was 0.44 mug per milliliter. The phosphate concentration of amniotic fluid appears to determine the expression of zinc inhibitory activity. The average phosphate concentration was 92 mug per milliliter. For 22 fluid samples tested, a phosphate-to-zinc ratio of 100 or less predicted a bactericidal fluid. A ratio between 100 and 200 predicted a bacteriostatic fluid. A ratio of greater than 200 predicted a noninhibitory fluid. The possible clinical significance of the ratio is discussed.

Amniocentesis↗
PubMed1976

Bacterial growth inhibition by amniotic fluid. VI. Evidence for a zinc-peptide antibacterial system.

The zinc bacterial inhibitory activity of amniotic fluid is dependent on the presence of a second, organic component contained in amniotic fluid. The second component is heat stable, resists proteolytic digestion, and is present in amniotic fluid throughout pregnancy. Further, the component may be a peptide with a molecular weight of less than 5,000 daltons. Phosphate reversal of amniotic fluid inhibitory activity may result from interference with the organic component rather than zinc.

Amniotic Fluid↗
PubMed1976

Creatine phosphokinase levels in children with severe developmental disturbances.

Serum creatine phosphokinase (CPK) levels were studied in individuals: 40 psychotic children suffering from childhood autism, atypical personality development, and childhood schizophrenia; five children with childhood aphasia; 22 children with severe personality disorders; 29 normal children and normal siblings of psychotic children; and 14 normal parents of psychotic children. Creatine phosphokinase levels from the entire population of adults and children were normally disturbed, and the mean CPK levels for the eight diagnostic groups were within normal limits. Those 22 children with personality disorders had significantly higher CPK levels than the other diagnostic groups. This relatively higher level of CPK may be related to vulnerability to later development of schizophrenic spectrum disorders. There was no apparent relationship between CPK levels and motor activity, nor was there any change in the level of CPK during a trial of psychoactive medication. Creatine phosphokinase levels remained relatively stable on test-retest determination.

Adolescent↗
PubMed1976

Humoral immunity to Streptococcus pneumoniae induced by a pneumococcal ribosomal protein fraction.

Isolation of a protective subfraction of ribosomes from Streptococcus pneumoniae has been achieved, and the immune response it induces has been investigated. Mice immunized with pneumococcal ribosomes or purified protein extracted from the ribosomal preparation (2-CE protein) exhibit similar survival rates upon challenge by virulent S. pneumoniae. In contrast, recipients of purified ribosomal ribonucleic acid were never protected against pneumococcal challenge. Serum from mice immunized with pneumococcal ribosomes or 2-CE protein passively immunized syngeneic recipients against pneumococcal challenge, whereas spleen cells from the same donors were unable to transfer immunity. Passive immunization with antiribosome serum could be abrogated by absorption with whole ribosomes, 2-CE protein, or various serotypes of S. pneumoniae (capsular types 2, 3, 6, and 14). Antiribosome serum significantly enhanced clearance of S. pneumoniae from mouse blood in vivo and in vitro. This required phagocytic cells, since antiribosome serum alone, with or without complement, supported growth of S. pneumoniae to an extent comparable to normal serum. The data suggest that the primary immunogen of pneumococcal ribosomes resides in the protein fraction. Further, the immunity induced by the protein fraction is mediated by antibody that appears to function as an opsonin for S. pneumoniae.

Animals↗
PubMed1976

Variability of protection in inbred mice induced by a ribosomal vaccine prepared from Salmonella typhimurium.

Ribosomal vaccines prepared from Salmonella typhimurium were effective immunogens in A/J inbred mice and C3H/HeTex, inbred mice. However, ribosomal vaccines were not protective in C57BL/6J inbred mice. A/J mice were protected against lethal challenge by attenuated S. typhimurium live-cell, ribosomal, phenol, and heat-killed vaccines. C3H/HeTex mice were protected by live-cell, ribosomal, and phenol vaccines but not the heat-killed vaccine. Only the live-cell vaccine gave significant protection in the C57BL/6J inbred mice. A comparison of the kinetics of infection in sham-immunized mice and mice immunized with ribosomes showed that ribosome preparations elicited protection against Salmonella infection in mice inherently sensitive and resistant to Salmonella.

Animals↗
PubMed1976

Isolation of a low-molecular-weight antibacterial system from human amniotic fluid.

A low-molecular-weight antibacterial system has been isolated from human amniotic fluid. The bacterial inhibitor requires the metal cation zinc and a peptide with a molecular weight of 630. The peptide component was purified using ultrafiltration, gel filtration, and ion-exchange chromatography. It can be inactivated by digestion with carboxypeptidase. The amino acid composition of the peptide is: 3 glutamine-glutamic acid, 2 glycine, and 1 lysine. Removal of zinc from the peptide has been shown to remove bacterial inhibitory activity.

Amniotic Fluid↗
PubMed1976

Linkage disequilibrium between functionally related enzyme loci of Drosophila mojavensis.

Gametic frequencies at four enzyme loci of the second chromosome of Drosophila mojavensis race B were obtained from six localities. The four loci were selected so that they code for functionally related enzymes; two code for esterases, one for xanthine dehydrogenase and one for acetaldehyde oxidase. In Drosophila the two latter enzymes are under the same regulatory control and their physiological functions might be related as well. Electrophoretic variants at the locicoding for these two enzymes were found not tobe in pair-wise linkage equilibrium. Other pair-wise combinations were in linkage equilibrium. It is argued that selectively maintained nonrandom associations may occur frequently between linked loci, the enzymatic products of which are functionally related, share common subunits or are under the same regulatory control.

Alleles↗