Search PubMed⌕ Search

Biomedical subjects

R Day

Publications and source records attributed to R Day.

251 records · Page 14Linked to original sources
PubMed1982

Dynorphin in bovine adrenal medulla. I. Detection in glandular and cellular extracts and secretion from isolated chromaffin cells.

The presence and secretion of immunoreactive dynorphin in bovine adrenal medulla and isolated adrenal chromaffin cells were examined and compared with those of immunoreactive leucine-enkephalin. Using an antiserum raised against dynorphin-(1-13), a sensitive and highly specific radioimmunoassay was developed. A nearly intact antigen was required for recognition by the antiserum since it did not react with leucine-enkephalin and reacted poorly with dynorphin-(1-12) (cross-reactivity 0.5%) and other fragments of dynorphin-(1-13). On the other hand, the antibody used for detection of leucine-enkephalin did not cross-react with dynorphin(1-13). Adrenal medulla acid extracts contained 195 times more immunoreactive leucine-enkephalin than dynorphin. However, the concentration of immunoreactive dynorphin in acid extract of freshly isolated adrenal chromaffin cells was only 1.4 times smaller than that of leucine-enkephalin. Incubation of the isolated chromaffin cells in the presence of acetylcholine, nicotine, high potassium, but not muscarine, induced a concomitant release of immunoreactive dynorphin (3.5-9% of total cell content) and leucine-enkephalin (6.5-11.4% of total cell content).

Acetylcholine↗
PubMed1982

Dynorphin in bovine adrenal medulla. II. Isolation, partial characterization and biological activity of two distinct molecules.

Two highly potent dynorphin-like peptides were isolated from bovine adrenal medulla by successive chromatography of an acid (HCl) extract on Sephadex G-10, carboxymethylcellulose, Sephadex G-50 and partition chromatography on Sephadex G-50. Amino acid analysis of both peptides revealed the presence of 24 amino acids including the composition of dynorphin-(1-13) and differing from each other only by a few residues. Both peptides were shown to have the same activity as dynorphin-(1-13) in the guniea pig ileum assay and reacted as well as dynorphin-(1-13) with a specific antibody (R-31) directed against the synthetic material.

Adrenal Medulla↗
PubMed1981

Life events and schizophrenia: the "triggering" hypothesis.

The present paper reviews the life event research specific to schizophrenia with the goal of assessing the extent to which recent empirical studies have implicated life stress variables as precipitants of acute episode of the disorder (i.e. the "triggering" hypothesis). Different methodological strategies used in life event research are reviewed along with the substantive findings from quasi-experimental and controlled studies of schizophrenic patients. It is concluded that stressful life events have been found to be part of the pool of factors associated with the onset of acute schizophrenic episodes, but evidence is still lacking to indicate that this association is necessary or direct one. Recommendations are made regarding the types of future studies required to fill the gaps in the existing literature.

Humans↗
PubMed1977

Detection of optical asymmetry in amino acids by gas chromatography for extraterrestrial space exploration: results of a new soil processing scheme with breadboard instrumentation.

The life-detection experiments of the Viking spacecraft are of an active biology type that will attempt to elicit metabolic responses from soil samples. Because bioresponses may be difficult to stimulate, it is desirable also to devise a purely chemical life-detection experiment. The unique chemical property of living systems on which such an experiment could be based is the optical activity of the amino acids that compose its protein. We have devised a new soil processing scheme which has been laboratory tested and for which we have built semi-automated breadboard instrumentation. The system involves the operations of heating, filtering, evaporation, conversion of the isolated amino acids to volatile diastereomers, injection onto a gas chromatographic column, and detection using a flame ionization detector. The breadboard form of the soil processing scheme and instrumentation has been successfully end-to-end tested.

Amino Acids↗
PubMed1976

Single-dose evaluation of a new enteric-coated aspirin preparation.

The bioavailability of a new enteric-coated tablet of aspirin (Ecotrin, Smith, Kline and French) was evaluated after single doses to eight volunteers. One tablet was administered to each subject on four occasions--twice after a light breakfast, once after a heavy breakfast and once after pretreatment with metoclopramide. The study utilized non-invasive techniques. The rate of absorption of aspirin was estimated by the time course of concentrations of salicylate in saliva, while the total bioavailability was determined by the recovery of total salicylate in urine. The urinary recovery of aspirin from all 32 trials was 575 +/- 25 mg (mean +/- standard error), representing 89% +/- 4% of the administered dose. The different treatments did not significantly alter the urinary recovery. The absorption of aspirin from the enteric-coated tablets was delayed and slow. Absorption was retarded by a heavy meal and hastened by pretreatment with metoclopramide. The effect of metoclopramide is consistent with the release of aspirin in the small intestine. Overall, the single-dose tests indicated satisfactory functioning of the enteric coating.

Adult↗
PubMed1975

The use of human adenovirus 2 in the study of the xeroderma DNA-repair defect.

Ultraviolet-irradiated adenovirus 2 assayed by counting plaques on monolayers of human fibroblast strains is up to 30-fold more sensitive than normal if the strains used as viral hosts are prepared from persons having xeroderma pigmentosum. This plaque assay has been used as an extremely discriminating technique in the study of the xeroderma repair defect. With this assay, every xeroderma fibroblast strain tested has been found to exhibit a DNA-repair defect, including those previously judged by other methods to have normal DNA repair.

Adenoviridae↗
PubMedDate not supplied

Compliance with quality of life data collection in the National Surgical Adjuvant Breast and Bowel Project (NSABP) Breast Cancer Prevention Trial.

This paper describes compliance with the completion of a quality of life questionnaire in the Breast Cancer Prevention Trial, a large multi-centre randomized trial that is studying the efficacy of Tamoxifen in preventing breast cancer. In the first 4875 women enrolled in the control arm of the study, there was a very high rate of questionnaire completion at baseline, 3 months, 6 months and 12 months of follow-up (89.8 per cent completed forms at 12 months). The sample was examined according to demographic and risk factors, as well as by recruitment cohort. There was a significantly poorer compliance rate for the most recently recruited cohort that was followed-up during a time of substantial external negative publicity related to clinical trial research. Nevertheless, the overall compliance with completion of quality of life data in this trial is very high, which is probably attributable to the high educational status of the trial participants.

Adult↗
PubMedDate not supplied

Preliminary trial of nonrecombinant interferon alpha in recurrent squamous cell carcinoma of the head and neck.

Fourteen patients with recurrent squamous cell carcinoma of the head and neck (SCCHN) were treated with 10 x 10(6) U of nonrecombinant interferon alpha (IFN) intramuscularly (IM) daily for 3 days every 28 days. There were 11 men and 3 women, with ages ranging from 48 to 74 years. Patients had previously been treated with surgery (9 patients), radiotherapy (13 patients), or chemotherapy (8 patients). All patients had measurable disease by physical exam and radiologic evaluation and a performance status of less than or equal to 2 (ECOG). Patients were treated for a minimum of 3 months and continued on therapy until disease progression. The dose and treatment schedule of IFN was well-tolerated. Toxicities included low-grade fever, mild anorexia, and malaise. Treatment was stopped in 1 patient due to the development of atrial fibrillation. One death occurred as a complication of aspiration pneumonia 2 weeks following the onset of therapy and was not felt to be related to IFN therapy. Of the 14 patients treated, there was 1 complete response (30+ months) of a base of tongue primary. Two patients had stabilization of disease (SD, 8 and 12 months). One patient had a mixed response with resolution of subcutaneous nodules. The remaining 10 patients died of progressive disease. Immunological assessment was performed on 8 patients. The 1 patient who had a complete response was noted to have markedly low pretreatment natural killer (NK) cell activity and a subsequent sharp rise in activity after initial treatment. We conclude that low-dose cyclic IFN is well-tolerated in patients with recurrent SCCHN and has potential antitumor activity.

Aged↗
PubMedDate not supplied

Protease inhibitors suppress in vitro growth of human small cell lung cancer.

The effect of the protease inhibitors Bowman Birk inhibitor (BBI) and aprotinin on the in vitro clonal growth of two human small cell lung cancer (SCLC) cell lines was investigated. In addition, the effect of BBI on the growth factor processing of proGRP by SCLC cells and on mRNA levels for prohormone convertase 1 and 2 (PC1 and PC2) in SCLC cells was examined. The protease inhibitors BBI and aprotinin significantly decreased growth in both SCLC cell lines studied. In NCI-H345 cells, BBI appears to inhibit the processing of proGRP to GRP, as indicated by Western blot analysis. NCI-H345 cells, when treated with BBI (100 micrograms/ml), also showed highly significant decreases of mRNA for PC1 and PC2 of about 50%. These data suggest that proteases serve an important role in the growth regulation of SCLC and that inhibitors of these proteases may be potent suppressors of SCLC growth at the level of the gene.

Aprotinin↗
PubMedDate not supplied

The behavioral morbidity of obstructive sleep apnea.

The behavioral morbidity associated with obstructive sleep apnea (OSA) includes symptoms of excessive daytime sleepiness (EDS), neurocognitive deficits, psychological problems, and possibly an increased chance of accidents. EDS is among the most frequently reported symptoms in patients diagnosed with OSA. The available data suggest that the primary cause of EDS is sleep fragmentation. The subjective measures of sleepiness include the sleep wake activity inventory and the epworth sleepiness scale. Sleepiness can also be evaluated objectively in the sleep laboratory using the multiple sleep latency test or the maintenance of wakefulness test. The neurocognitive manifestations of OSA include impairments in vigilance, concentration, memory, and executive function. There is no agreed on consensus as to how to best quantify neurocognitive deficits in this population. Symptoms consistent with depression or personality changes have also been described, but are likely to be correlates of EDS and/or the chronicity of the disorder. Manifestations of the behavioral morbidity of OSA are reversible, but dependent on the degree of normalization in sleep-disordered breathing and the individual's sleep habits.

Accidents, Traffic↗
PubMedDate not supplied

The frequency of Baker's cysts associated with meniscal tears.

We reviewed the films of 1760 patients who had magnetic resonance image scanning of the knee joint to assess the most common pathologic changes associated with an incidental finding of a Baker's cyst. Of the 1760 knees scanned, Baker's cysts were noted in 238. The cysts were classified as small (55%), medium (30%), or large (15%) and were primarily found on the medial side of the knee (94%). The menisci were evaluated and changes were classified as complete tears, where signal contacts the surface, or degenerative intrasubstance tears. One hundred eleven (47%) complete meniscal tears were found, and 88 (37%) degenerative tears. The majority of tears were found in the posterior horn of the medial meniscus (65 complete tears and 45 degenerative tears). Thus, 199 tears were found in 170 knees, and 106 of the 170 knees (62%) had tears of the posterior horn of the medial meniscus. Baker's cysts are frequent findings on physical examinations and on magnetic resonance imaging scans of the knee. They are thought to be due to intraarticular pathologic changes, usually posterior meniscal tears. This study documents the association between Baker's cysts and meniscal tears and notes that a complete tear is not necessary for the cyst to be present.

Adolescent↗
PubMedDate not supplied

A prospective study of the neurological effects of lead in children.

In the past three years, our research group has investigated the relationship between lead exposure and mental and behavioural development. This has been carried out through studies in children and studies in animals. Earlier studies in children have shown that associations might be expected between environmental exposure to lead and various aspects of cognitive and behavioural development. Our study has examined, and continues to examine, a cohort of 151 children subdivided into three groups according to the level of lead exposure during early in utero development as assessed by maternal blood lead concentration and water lead exposure in early pregnancy. Data amassed to date include measurement of psychometric function and postnatal development at the ages of 1 and 2, together with biochemical measures of lead exposure. Assessment will continue through to early scholastic performance and will include measurement of deciduous tooth lead concentration as an integrated measure of long-term exposure.

Child↗