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Biomedical subjects

C Johnson

Publications and source records attributed to C Johnson.

At least 469 records · Page 26Linked to original sources
PubMed1983

Comparative analysis of the suppression by cord blood mononuclear cells of adult and neonatal lymphocytes.

The spontaneous or in vivo generated suppressor cell activity of adult and cord blood has been quantitated and compared in a system that examines the regulation of the T-cell response to mitogen. We confirmed previous findings that spontaneous suppressor cell activity is stronger in cord blood. This is only true, however, in a system that uses adult lymphocytes as responder cells. Cord blood responder cells are significantly more resistant to suppressor signals than are adult cells. Thus, the influence of cord blood suppressor cells on cord blood effector cells is equivalent to that seen in similar cocultures containing only adult cells. Spontaneous suppressor cell activity decreases rapidly among cultured adult cells but remains unaffected in cultures of cord cells for at least 4 days. Suppressor cell activity induced by concanavalin A (Con A) was significantly greater with adult cells. The sum of the spontaneous and Con A-induced suppressor cell activity among both cord and adult mononuclear cells was identical, indicating that the total potential suppressor cell function of the two populations is similar and that assays of spontaneous or Con A-induced suppressor cell activity are likely to be examining the same cell population. These findings strengthen the hypothesis that while fetal immunoregulatory cells may be potent suppressor of maternal (adult) lymphocytes, internal (fetal) balance is maintained by having responder cells relatively resistant to these fetal suppressor cells.

Adult↗
PubMed1983

Comparative analysis of the heterogeneity of mononuclear cells present in adult and cord blood by simultaneous examination of multiple phenotypic characteristics.

In an attempt to better relate specific membrane characteristics of human adult and cord blood lymphocytes to specific functional activities, the phenotypic differences that exist in these two populations have been examined. Cord blood cells have considerably more spontaneous suppressor cell activity than adult cells. A technique that allows cells to be examined simultaneously for their ability to ingest latex beads, react with specific monoclonal antisera, bind sheep erythrocytes, or react with the Fc portion of IgG was used. As well as assessing fresh populations, phenotypic changes that occur when such cells are held in culture or stimulated with phytohemagglutinin for 3 days were sought. Many differences were found when comparing these mononuclear populations. These included the observations that 12% of adult and 9% of cord blood E-rosette-forming cells ingest latex beads and that 9% of OKT3 reactive cells in both populations did not form E rosettes. In cord blood 58% of T cells that bind OKT8 do not form E rosettes. A similar percentage of cord blood T8-positive cells express a receptor for Fc gamma, such cells being very uncommon in adult blood. Four "monocyte" subpopulations were identified in both samples. One such population (an OKM1- and Fc gamma-positive, nonphagocytic cell) was three times more common in cord blood. In cord blood some OKM1-positive cells also appeared to be simultaneously OKT8 positive. These phenotypic variations forward populations that may be candidates responsible for the functional differences noted in vitro.

Adult↗
PubMed1983

Identification of excessive back disability with the Faschingbauer Abbreviated MMPI.

Tested the accuracy of the MMPI and the FAM for predicting appropriate vs. inappropriate disability (illness behavior) in low back pain patients (N = 123). When the Hypochondriasis and Hysteria scales were used, both versions had a 79% hit rate for inappropriate disability and at least an 80% overall correct classification rate. The resulting brief screening measure included 52 items.

Adaptation, Psychological↗
PubMed1983

Relation between gastric secretion of acid and urinary excretion of calcium after oral supplements of calcium.

The object of this study was to determine in 12 healthy subjects the relation between gastric secretion of acid and absorption of calcium from two different preparations of calcium, as judged from increased outputs of calcium in the urine. The increase in urinary output of calcium after solid calcium carbonate was greater in the subjects with the most gastric secretion of acid. The absorption of calcium after a solution of monocalcium citrate was independent of gastric secretion of acid. In the four subjects with the least gastric secretion of acid, there was no absorption of calcium after calcium carbonate, but the absorption after monocalcium citrate was as great as that for those who secreted greater amounts of acid.

Calcium↗
PubMed1983

Changes in internal pH associated with initiation of motility and acrosome reaction of sea urchin sperm.

The changes in the intracellular pH (pHi) of sea urchin sperm associated with motility initiation and acrosome reaction were investigated using uptake of two different probes; 9-aminoacridine and methylamine, as a qualitative index. Sperm suspended in Na+-free sea water were immotile and able to concentrate these amines 20-fold or greater indicating that pHi is more acidic than the external medium (pHo = 7.7). This uptake ratio was essentially constant over a wide range of probe and sperm concentrations. Discharge of the pH gradient with specific ionophores (nigericin, monensin, and tetrachlorosalicylanilide) or nonspecifically using low concentration of detergents (Triton X-100 and lysolecithin) all resulted in the release of the probes indicating they are indeed sensing the pH gradient across the sperm membrane. Addition of Na+ to sperm suspended in Na+-free sea water resulted in activation of motility with concomitant efflux of the probes indicating the alkalinization of pHi by 0.4-0.5 pH units. That this pHi change is the causal trigger of motility was suggested by experiments using NH4Cl and nigericin, which increased the pHi and resulted in activation of motility in the absence of Na+. When sperm were directly diluted into artificial sea water (motility activated), a slow reacidification of pHi was observed in one species of sea urchin (L. pictus) but not in the other (S. purpuratus). This acidification could be blocked by mitochondrial inhibitors, verapamil, or the removal of external calcium suggesting that the increase in metabolic activity stimulated by the influx of Ca2+ is responsible for the reacidification. Induction of acrosome reaction further alkalinized the pHi by about 0.16 pH units and was also followed by prolonged reacidification which correlated with the observed increase in Ca2+ uptake. Either mitochondrial agents or the removal of external Ca2+ could also block this pHi change suggesting a similar mechanism is involved.

Acrosome↗
PubMed1983

Fetal calf ligament fibroblasts in culture secrete a low molecular weight collagen with a unique resistance to proteolytic degradation.

A highly unusual collagen was secreted by fibroblasts cultured from 150- and 270-d-old fetal calf nuchal ligaments. Purification revealed that this protein (which may be synthesized in a higher molecular weight form) was precipitated at unusually high concentrations of ammonium sulfate and was also eluted from DEAE-cellulose at greater salt concentrations than were types I and III procollagens. On SDS PAGE, the collagenous protein exhibited an Mr of approximately 12,750 that was not altered in the presence of reducing agent. The low molecular weight collagen (FCL-1) was sensitive to bacterial collagenase and had a [3H]glycine content comparable to that found in type I procollagen, although the [3H]Hyp to [3H]Pro ratio was 0.43. FCL-1 was not cleaved by human skin collagenase, mast cell protease, trypsin, Staphylococcal V8 protease, or proteinase K at 37 degrees C. The collagen was susceptible to trypsin, but not to V8 protease, only after heating at 80 degrees C for 30 min. Preliminary structural studies indicate that FCL-1 was resistant to cleavage by CNBr but exhibited limited proteolysis with pepsin. Both 150- and 270-d-old fibroblasts produced comparable levels of interstitial (types I and III) procollagens, which comprised approximately 70% of the total protein secreted into the culture medium. However, 270-d-old (term) fibroblasts secreted approximately 50% more FCL-1, as percent of total culture medium protein, in comparison to the cells from the earlier gestational stage. This collagen may therefore play a role in the development of the nuchal ligament.

Animals↗
PubMed1983

Effect of forearm abduction on the ulnar collateral ligament.

Seven fresh cadaveric elbows from one woman and three men were studied to determine if the forearm abduction mobilization commonly used to restore the last 20 degrees of elbow extension produced an increase in the length of the anterior band of the ulnar collateral ligament. Initial ligament length and maximum length during mobilization were measured with a dial caliper and recorded on videocassette. Results indicated no significant difference between ligament lengths at rest and during the mobilization. The mechanism by which the forearm abduction mobilization restores elbow extension remains unknown.

Aged↗
PubMed1983

Psychopharmacological treatment of anorexia nervosa and bulimia. Review and synthesis.

Recent reports have indicated that the incidence of anorexia nervosa and bulimia has increased over the last several years. Both of these syndromes present serious treatment challenges to clinicians and in an effort to deal more effectively with these disorders several pharmacological interventions have been attempted. This article reviews the range of pharmacological interventions used with anorexia nervosa and bulimia patients. The purpose of the review is to present our current knowledge regarding the efficacy of these medications and to offer methodological recommendations that will enhance future research efforts.

Adrenocorticotropic Hormone↗
PubMed1983

Fibrinolytic activity after administration of diflunisal and aspirin. A double-blind, randomized, placebo-controlled clinical trial.

A double-blind, randomized, placebo-controlled clinical trial was conducted to determine whether fibrinolysis was increased by the chronic administration of aspirin or diflunisal. Healthy male and female volunteers were randomized to receive either aspirin (1,300 mg every 12 h; 10 subjects), diflunisal (1,000 mg initially, then 500 mg every 12 h; 10 subjects), or placebo (10 subjects) for 8 days. Fibrinolytic activity was examined with the clot lysis assay, using native whole blood, platelet-rich plasma, and platelet-poor plasma, and with the kaolin-activated euglobulin lysis test. In addition, measurements were made of fibrinogen, fibrin/fibrinogen degradation products, plasminogen, and the thrombin time. Clot lysis was greater in whole blood and platelet-rich plasma than in platelet-poor plasma, and increased lysis was observed in specimens obtained in the afternoon as compared to those obtained in the morning. Fibrinolytic activity in the afternoon samples was significantly enhanced by both aspirin and diflunisal at the start of the trial (p less than 0.05), but by the afternoon of day 8, only aspirin showed some enhancement. Fibrinolytic activity, as measured by the euglobulin lysis time, actually declined in all study groups during the course of drug administration. No significant changes were recorded in any of the other assayed hemostatic parameters. We conclude that aspirin and diflunisal exert a modest, nonsustained enhancing effect on fibrinolysis in normal subjects.

Adult↗
PubMed1983

Preliminary investigation of bulimia and life adjustment.

Despite the reported increase in the incidence of bulimia, little is known about the life adjustment of bulimic patients. The authors surveyed 80 women who met the DSM-III criteria for bulimia regarding their adjustment in the areas of work, social and leisure activities, relationship with extended family, role as spouse, role as parent, and membership in the family unit. The life adjustment of the bulimic sample was significantly poorer in all areas than that of a normal community sample and was most similar to that of a comparison group of alcoholic women.

Adolescent↗
PubMed1983

Detection of a light-sensitive pool of cGMP in goldfish cone color receptors by immunocytochemistry.

A procedure for the immunocytochemical localization of cGMP in the goldfish retina is described. The procedure is then used to evaluate the presence of cGMP in cone color receptors in retinas from dark-adapted and light stimulate fish. The results show that cone color receptors in dark-adapted retinas contain large amounts of immunocytochemically defined cGMP in the ellipsoid region, which are greatly reduced after light exposure.

Animals↗
PubMed1983

Optimal detection of oligoclonal bands in CSF by silver stain.

We applied a sensitive silver nitrate stain to SDS-polyacrylamide gels to detect oligoclonal bands in unconcentrated CSF. Silver staining took less than 3 hours and gave easily readable bands in 93% of MS patients. In contrast, standard Coomassie Blue stain was positive in only 53%. Maximum resolution and numbers of bands resulted when silver staining was used on 10 to 20 microliters of CSF. Silver staining of SDS-polyacrylamide gels permits reliable oligoclonal band detection on small volumes of unconcentrated CSF.

Electrophoresis, Polyacrylamide Gel↗
PubMed1983

Delayed hypersensitivity to tetanus toxoid in man: in vivo and in vitro studies.

The frequency of positive delayed hypersensitivity skin test reactions to tetanus toxoid in 47 healthy volunteers was 80%. The frequency of immediate hypersensitivity was low (8%) and there was less discomfort than with streptokinase or PPD. There was good correlation between leukocyte migration inhibition and delayed hypersensitivity skin testing, and a quantitative relationship was demonstrated between diameter of cutaneous reaction and degree of leukocyte migration inhibition. No relationship was demonstrated between any measures of immune responsiveness and the interval from the last booster immunization. It was concluded that tetanus toxoid is a valuable antigen for assessment of delayed hypersensitivity in man.

Adolescent↗
PubMed1983

Acute myocardial infarction in sickle cell anemia.

Typical acute myocardial infarction in a well-documented case of sickle cell disease, to our knowledge, has not been reported. A patient with hemoglobin SS proved by electrophoresis with typical clinical manifestation and diagnostic ECG changes died suddenly. Autopsy findings were confirmatory, but no atherogenic lesions were present. Possible mechanisms for acute infarction are discussed, including sludging of sickle cells, coronary spasm, thrombus formation, and severe anemia associated with any or all of the aforementioned.

Adult↗
PubMed1982

Schizophrenia and reduced cyclic AMP production: evidence for the role of receptor-linked events.

Reduced cyclic AMP (cAMP) production has been found in platelets of schizophrenic patients. cAMP is generated physiologically as a result of a series of steps beginning with receptor activation by a ligand, progressing through activation of the enzyme protein, adenylate cyclase. The deficit of cAMP found in the schizophrenic population may occur at any one, or at multiple steps in this cascade. The present study attempts to discriminate whether impaired adenylate cyclase itself was responsible for the cAMP deficit or whether abnormalities in receptor events or linkage are present in schizophrenics. The production of cAMP following direct stimulation of adenylate cyclase by NaF was contrasted with receptor mediated activation of adenylate cyclase by prostaglandin E1 (PGE1) in disrupted platelet preparations from schizophrenics and normal controls. cAMP formation stimulated by NaF was not different in platelets of schizophrenics as compared to controls, however, platelets of schizophrenics showed reduced response to PGE1 stimulation. The authors interpret these findings as evidence for a membrane associated abnormality of either receptor or receptor-adenylate cyclase linkage in the schizophrenias.

Adenylyl Cyclases↗