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Biomedical subjects

A Clark

Publications and source records attributed to A Clark.

At least 271 records · Page 15Linked to original sources
PubMed1985

Review panels for involuntary psychiatric patients: which patients apply?

This study attempted to identify which involuntary patients apply to Review Panels for discharge. Four hundred and eighty-seven (487) patients who applied for review at a provincial mental hospital during a five-year period were compared, on 27 variables, with 2,966 patients who, although eligible to apply, chose not to do so. The groups differed on nineteen of the twenty-seven variables. Discriminant analysis was used to identify the ten best predictors of who will apply to the Review Panel. The profile thus derived of the Review Panel applicant, may be useful to management teams who could try to formulate a plan that would reduce the probability that the patient will apply.

Canada↗
PubMed1984

Properties of a herpesvirus-transformed hamster cell line: immunogenicity of sublines of high and low metastatic potential.

The immunogenicity of a herpesvirus hominis type-2-transformed hamster cell line (HSV-2-333-2-26) of low spontaneous metastatic ability was compared with that of its two in vivo-derived sublines of increased metastatic potential. The parent (HSV-2-333-2-26) tumour was immunogenic as assessed by protection against tumour challenge afforded by implantation of irradiated tumour cells or tissue. In contrast, the two metastatic sublines, designated Met A and Met B, were non-immunogenic as defined by the above critera . However, the parent Met A and Met B tumours were shown to possess a common antigen(s), since immunization with irradiated parent tumour cells afforded protection to challenge with Met A or Met B. Immunization with the metastatic sublines, however, gave no protection to homologous or heterologous tumour challenge. Bacillus Calmette-Guérin (BCG) inoculated in admixture with irradiated tumour cells and followed 7 days later by one immunization with X-irradiated tumour cells alone, increased host immunocompetence to subsequent homologous or cross-tumour cell challenge with parent, Met A or Met B cells. The immunity raised by using BCG plus irradiated tumour cells was shown to be specific to antigens expressed on the HSV-2 parent cell line and its metastatic sublines. In addition, BCG admixed with live inocula of parent, Met A or Met B cells induced contact suppression of in vivo tumour growth of the parent cells, but not of Met A or Met B cells. It is suggested from these studies that the parent tumour possesses a tumour-specific transplantation antigen(s) ( TSTAs ) which is not functionally active on its metastatically derived sublines. Common antigens, shared between the parent and Met A and Met B cells, are detectable by cross-challenge experiments, but they themselves appear not to be immunologically offensive. The loss of immunogenicity is discussed as a possible mechanism for the in vivo selection of sublines with increased metastatic potential.

Animals↗
PubMed1984

Muscle O2 gradients from hemoglobin to cytochrome: new concepts, new complexities.

The capillary is the principal barrier at high Vo2. Mathematical modelling indicates that at high flow and Vo2 the time required for release of O2 is greater than red cell transit time in some capillaries. This convective shunting appears to be particularly important in the myocardium. The Mb acts to buffer Po2 below 5 Torr during muscle contraction. This greatly increases the transcapillary O2 gradient and promotes O2 delivery. During voluntary movements, Mb should act as a major O2 source in parallel with capillaries. The Kroghian model of the capillary as a "low-resistance" point source of O2 supplying a spatially uniform sink appears to be the reverse of the actual geometry of O2 supply to working red muscle.

Animals↗
PubMed1984

Non-uniform distribution of islet amyloid in the pancreas of 'maturity-onset' diabetic patients.

Quantitative morphometry of the pancreases of five 'maturity-onset' diabetic subjects has demonstrated more amyloid in islets of the head, body and tail (where it was found in a mean 29% of the islets occupying a mean 11% islet area) than in islets of the 'pancreatic-polypeptide-rich' lobule of the head (where amyloid was found in a mean of 3% of the islets occupying a mean of 0.7% islet area, both p less than 0.005). The non-uniform amyloid distribution may relate to the hormone content of the islet; the head and tail contained significantly more A, B and D-cells than the pancreatic-polypeptide-rich lobule in both non-diabetic subjects (n = 8) and diabetic patients (n = 5; p less than 0.005). This result is compatible with the previous suggestion that amyloid may be derived from insulin or its precursors.

Aged↗
PubMed1984

Anti-androgens do not alter androgen-dependent characteristics of acid phosphatase in the rat ventral prostate.

When administered to intact adult male rats, cyproterone acetate (10 mg/day), flutamide (15 mg/day), or Compound I (1 mg/day) caused a significant decrease in the organ weight to body weight ratios, with a concomitant rise in the specific activity of prostatic acid phosphatase. These compounds do not affect two other markers of androgen activity in the prostate. Neither the percentage inhibition of acid phosphatase activity by tartrate nor the appearance of the secretory band of acid phosphatase on polyacrylamide gels was altered by the administration of anti-androgens. When administered to castrated rats given doses of 5 alpha-dihydrotestosterone (250-750 micrograms/day), flutamide (15 mg/day) was unable to alter the percentage inhibition of acid phosphatase activity by tartrate, or the pattern of activity on polyacrylamide gels. These results suggest that these anti-androgens affect only some of the androgen-dependent functions of the prostate.

Acid Phosphatase↗
PubMed1984

Cutaneous lymphomatoid granulomatosis: a rare cause of recurrent skin ulceration.

We report the case of a 34-year-old male who presented with recurrent skin ulceration due to lymphomatoid granulomatosis. Monoclonal antibody studies showed a high T helper (T4):T suppressor (T8) cell ratio in both the lesions and the peripheral blood. Plasma cells in the infiltrate showed IgA lambda staining but as yet no monoclonal immunoglobulin has been identified in the blood or urine. Lymphocytes bearing markers of immature cells (T10) were observed in the tissue and blood.

Adult↗
PubMed1983

Declining T-cell immunity to influenza, 1977-82.

Influenza-A-virus-specific, HLA-restricted, cytotoxic T-cell immunity, measured in 189 volunteers in the six years 1977-82, showed a sharp decline from 1978. It is shown that natural infection with influenza-A virus boosts cytotoxic T-cell memory. The decline in T-cell immunity is probably associated with the low prevalence of influenza-A-virus infection since 1978.

Adolescent↗
PubMed1983

Further characterization and reconstitution of the purified Ca2+-pumping ATPase of heart sarcolemma.

The Ca2+-pumping ATPase has been isolated from calf heart sarcolemma by calmodulin affinity chromatography (Caroni, P., and Carafoli, E. (1981) J. Biol. Chem. 256, 3263-3270) as a polypeptide of Mr about 140,000. The purified enzyme has high affinity for Ca2+ in the presence of calmodulin (Km about 0.4 microM) but shifts to a low affinity state (Km about 20 microM) in its absence. Calmodulin increases also the Vmax of the enzyme. The effects of calmodulin are mimicked by phosphatidylserine and by a limited proteolytic treatment of the enzyme with trypsin. The purified ATPase can be reconstituted in asolectin liposomes, where it pumps Ca2+ with an approximate stoichiometry to ATP of 1. The purified (and reconstituted) enzyme is not phosphorylated by added ATP and cAMP-dependent protein kinase under conditions where the enzyme in situ is stimulated concomitant with the phosphorylation of the sarcolemmal membrane (Caroni, P., and Carafoli, E. (1981) J. Biol. Chem. 256, 9371-9373). Hence, the target of the regulatory phosphorylation system is not the ATPase molecule. The purified ATPase cross-reacts with an antibody raised against the erythrocyte Ca2+-pumping ATPase. Under the same conditions, the purified sarcoplasmic reticulum Ca2+-ATPase does not react. The proteolytic splitting pattern of the purified heart sarcolemma and erythrocyte enzymes are similar but not identical.

Animals↗
PubMed1983

Functional health status levels of primary care patients.

A cross-sectional study was conducted on functional status of adults visiting primary care practices. Limitations in physical and mental function were assessed independently in 28 practices by patients (N = 1,227) and physicians (N = 47) using a simple global index of disability. Results indicated 12% of patients rated their physical limitations as major and 8% rated major emotional limitations during the past month. Comparable assessments by physicians were 5% and 4%, respectively. Differences between patients and physicians were statistically significant and are demonstrated to be clinically relevant. Patients' functional limitations were associated with increased utilization of ambulatory care, older age, lower level of education, unemployment, and a primary diagnosis of a chronic condition. We conclude that functional status can be routinely recorded in medical practice to help describe severity, predict utilization, and improve the physician-patient relationship.

Activities of Daily Living↗
PubMed1983

Nine standardized scales for evaluating treatment outcome in a mental health clinic.

Analyzed psychometrics of a package of standardized scales used to assess mental health treatment outcomes in a VA cost-effectiveness study (N = 451). Nine scales were derived: Family involvement, involvement with friends, labor market participation, symptomatology (both self-reported and therapist rated), substance abuse (alcohol and drugs), client satisfaction, and client goal attainment. Scales were drawn from several existing instruments, including the Denver Community Mental Health Questionnaire (CMHQ), the Symptom Checklist 90 (SCL-90), the Global Assessment scale, and others. Item-item and item-total correlations showed each scale to have high internal consistency. Principal components analysis demonstrated distinct factors for each scale and good clustering of items within scales. All scale items are discrete choice and have excellent interrater reliability. Validity was corroborated by multiple regression, which showed different scales to be sensitive to different predictors of follow-up status.

Adult↗
PubMed1983

Interference following dual inoculation with influenza A (H3N2) and (H1N1) viruses in ferrets and volunteers.

The effects of simultaneous inoculation with two attenuated influenza A viruses was studied in ferrets and volunteers. Groups of ferrets were inoculated with an influenza A (H3N2) or (H1N1), virus or a combination of both viruses: the temperature response, serum and local antibody response, and the change in nasal wash protein concentration was determined. The results showed that both viruses were attenuated for ferrets, and that inoculation with both viruses together did not cause clinical reactions. Serological studies on paired serum samples obtained from ferrets showed that both viruses when given separately infected all the inoculated animals; however, dual infection resulted in all ferrets being infected with the influenza A (H3N2) virus strain, but this infection interfered with infection by the influenza A (H1N1) strain. Similar investigations were carried out in volunteers. Again, the clinical reactions and temperature response of volunteers to infection by one or other of the viruses showed both strains to be attenuated for man even when given together. In addition, no adverse clinical reactions were seen in volunteers inoculated with both viruses simultaneously. Serum antibody studies showed that infection by influenza A (H1N1) virus interfered with infection by the influenza A (H2N2) virus strain. These results show evidence of interference by influenza A viruses; however, the direction of interference was one-way, and differed for ferrets and for volunteers.

Animals↗
PubMed1983

Quantitative morphology of endocrine cells in human fetal pancreas.

Sections of pancreas from human fetuses, 6-20 weeks gestation, were stained with immunoperoxidase for insulin (B cells), glucagon (A cells), pancreatic polypeptide or somatostatin (D cells). Morphometric analyses were performed on sections from head and tail regions of each fetus. No stained cells were found at 7 weeks. A, B, pancreatic polypeptide and D cells were found at 9 weeks in primitive islets or as isolated cells adjacent to duct cells. There was no relationship between the density of each endocrine cell type and fetal age, but there was a significant increase in the relative density (percentage total endocrine cells) of D cells from 10-20 weeks (p less than 0.01). The tail contained significantly more A cells (p less than 0.05) and less pancreatic polypeptide cells (p less than 0.01) than the head but similar densities of B and D cells. Lobules containing a high density of pancreatic polypeptide cells and few A cells were found in the posterior part of the head in six fetuses, aged 10-20 weeks.

Cell Count↗
PubMed1983

The stoichiometry of the Ca2+-pumping ATPase of erythrocytes.

The stoichiometry of the erythrocyte Mg2+ dependent Ca2+-stimulated ATPase has been determined in a reconstituted system. Purified Ca2+ ATPase was incorporated into calcium impermeable liposomes and the ATP dependent calcium uptake was determined simultaneously with the hydrolysis of ATP. The results indicate that 1 gram atom of calcium is transported for each gram molecule of ATP hydrolysed, i.e., an ATP/Ca2+-stoichiometry of 1.

Adenosine Triphosphate↗
PubMed1983

Detection and characterization of natural killer cells in Syrian golden hamsters.

Natural killer (NK) cell activity was observed in the peripheral blood and spleen of 8- to 10-week-old Syrian golden hamsters, but not in the bone marrow or thymus. Low, but significant, levels of cytotoxicity were also observed in mesenteric and axillary lymph nodes and cells harvested from the peritoneum. Cytotoxicity, in a 4-hr 51Cr-release assay, was found to be nylon wool non-adherent and was significantly reduced by treatment with trypsin or incubation at 37 degrees C for 18 hr. Natural cytotoxicity was shown to be low at 1 week of age, but increased to a maximum at 8 weeks and was maintained into old age. Correlation was observed between peripheral blood cytotoxicity and the presence of large, often granular, lymphocytes following fractionation of effector cells by Percoll discontinuous gradient separation. These findings are compared with previous studies in hamsters, where the results of longer-term cytotoxicity tests differ in some respects to those of the present study.

Aging↗
PubMed1983

Reduced susceptibility to natural killer cell lysis of hamster tumours exhibiting high levels of spontaneous metastasis.

The natural killer (NK) cell susceptibility of hamster tumours exhibiting high and low levels of spontaneous metastasis in vivo was investigated. The parent cell line (HSV-2-333-2-26), which was weakly metastatic, and the NK-sensitive target line K562 were both sensitive to hamster natural killer cell activity. In contrast, 2 in vivo cloned sublines, designated met A and met B, exhibited a high level of spontaneous metastasis and were shown to be weakly or non-susceptible to hamster UK reactivity.

Animals↗