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Biomedical subjects

R Stark

Publications and source records attributed to R Stark.

At least 73 records · Page 4Linked to original sources
PubMed1990

Pestivirus glycoprotein which induces neutralizing antibodies forms part of a disulfide-linked heterodimer.

Neutralizing monoclonal antibodies directed against hog cholera virus (HCV) precipitated two HCV-encoded glycoproteins, HCV gp55 and HCV gp33. Immunoassay with bacterial fusion proteins and Western immunoblotting with extracts from infected cells revealed that the antibodies recognized only HCV gp55. Coprecipitation of HCV gp33 was shown to be due to intermolecular disulfide bridges. One of the antibodies also reacted with the major glycoprotein of another pestivirus, bovine viral diarrhea virus (BVDV). The analogous BVDV glycoproteins exhibited a distribution of cysteine residues which was almost identical to that of HCV gp55 and gp33. The two BVDV glycoproteins were also linked by disulfide bridges.

Animals↗
PubMed1990

Peripheral blood T cell activation after radioiodine treatment for Graves' disease.

Radioiodine therapy for Graves' thyrotoxicosis produces a rise in thyroid autoantibodies in the first three months after treatment, but little is known of its effects on T cells. We have therefore followed the changes in T cell subsets in sequential samples from 23 patients with Graves' disease treated with radioiodine, using dual-colour flow cytometry. In the first month after treatment there was a significant rise in activated T cells, identified by the markers HLA-DR (la) and CDw26/Ta1 (p less than 0.025 in both cases). CD45RO-positive T cells, which are the primed population containing memory cells, also increased (p less than 0.025), but there was no change in CD45R-positive, resting T cells or in the CD4 to CD8 (helper to cytotoxic/suppressor) ratio. Vicia villosa-binding T cells, containing the contrasuppressor population, showed a more variable response, but the trend was to an overall increase from pre-treatment values (p less than 0.025). The changes did not appear to be related to antithyroid drug treatment, since they were seen irrespective of whether patients continued such therapy. These results suggest that T cell activation and enhanced contrasuppressor activity may in part be responsible for the rise in autoantibodies after radioiodine. The T cell changes could also contribute to the worsening of ophthalmopathy seen in some radioiodine-treated patients.

Adult↗
PubMed1990

A TAFE strategy for biotechnology skills training.

The outline of a strategy for training technicians who will undertake biotechnology-oriented tasks as employees is the focus of this review. Technical and Further Education (TAFE) in Western Australia has recently restructured electives offered in certificate and diploma courses of Applied Science. The aim of restructuring was to allow a broader choice catering for specialized streams. With a few additions it would be possible to list a set of biotechnology options for technicians specializing in this area. After identifying employers in Western Australia, data on technician employment characteristics and training needs was gathered through a survey and used to formulate a future development strategy. In the past little attention has been given anywhere in Australia to the training needs of this group. The availability of such appropriately trained employees will increasingly be recognized as a vital link in the success of any biotechnology enterprise.

Australia↗
PubMed1990

Nurses bring primary health care to industrial workers.

Progress in bringing health care to the workplace lags considerably behind progress in bringing health care to where people live. Experience in Botswana shows that the family nurse practitioner--a registered nurse midwife with one year of post-basic training--can provide useful preventive and curative services to people in their places of work.

Botswana↗
PubMed1989

[Molecular characterization of the hog cholera virus].

The molecular biology of hog cholera virus (HCV) was studied. After reverse transcription of the viral RNA the cDNA was cloned in the expression vector lambda gt11. HCV clones were identified using antibodies as a probe. Partial sequencing of one HCV-derived cDNA clone revealed a high degree of homology to a portion of the bovine viral diarrhea virus (BVDV). One goal of these studies is the preparation of defined, effective and safe vaccines against pestiviruses.

Amino Acid Sequence↗
PubMed1989

Amniotic fluid prolactin levels in rhesus isoimmunized patients.

The concentration of prolactin in the amniotic fluid (AFPRL) was measured in 75 samples obtained in the third trimester of 14 isoimmunized women. There was a uniform decline in prolactin levels with advancing gestation in each pregnancy (r = -0.89 to -0.99). The decline in AFPRL was similar in uncomplicated pregnancies. AFPRL levels were not predictive of umbilical cord hemoglobin or bilirubin levels and amniotic fluid lecithin/sphingomyelin ratio.

Amniotic Fluid↗
PubMed1989

Hog cholera virus--characterization of specific antiserum and identification of cDNA clones.

A specific antiserum was raised against the pestivirus inducing hog cholera (hog cholera virus, HCV). Using immunoprecipitation and SDS-PAGE, this antiserum served for comparison of HCV-induced proteins with those from a related and better characterized pestivirus, bovine viral diarrhea virus (BVDV). In addition to immunological relationships, the apparent molecular weights of some proteins induced by both viruses were quite similar. HCV genomic RNA was found to be about 12 kb in length, comparable to BVDV RNA. cDNA was synthesized starting from RNA isolated from partially purified virions and cloned in lambda gt11. Screening with the antiserum resulted in identification of several positive clones. Partial sequencing of one HCV-derived cDNA clone revealed a high degree of homology to a portion of the BVDV sequence.

Amino Acid Sequence↗
PubMed1989

Haemophagocytic syndrome complicating acute lymphoblastic leukaemia.

A 41 year old female developed reactive haemophagocytic histiocytosis secondary to herpes simplex infection, during remission induction for acute lymphoblastic leukaemia. She recovered fully with acyclovir and supportive treatment. Previous publications on the association between acute lymphoblastic leukaemia and haemophagocytic syndrome are reviewed, and the nature of the haemophagocytic disorder is discussed.

Acyclovir↗
PubMed1989

[The value and consequences of nocturnal pulse oximetry in severe heart failure, suspected myocardial infarct and acute cerebral ischemia].

On extensive clinical monitoring of nocturnal oxygen saturation (Minolta Pulsox 7) we observed three groups with an increased risk of nocturnal hypoxemia. The hypoxemia was classified in terms of severity, frequency and duration into six groups of findings. The degree of oxygen desaturation was positively correlated to the severity of disease. In the group of patients with heart failure (NYHA III-IV) (n = 13) four had severe hypoxemia, and a history of previous cardiac infarction; three of them wore a pacemaker. Decrease in saturation after acute cerebral ischemia was seen in particular in patients with oropharyngeal disorders (dysphasia and dysphagia). In the group with suspected myocardial infarction (n = 16) we measured frequent short drops in saturation in ten patients, eight of whom were heavy snorers. Because of its simplicity, non-invasiveness and high information yield, especially in acute patients, pulse oximetry is important for clinical diagnosis, with immediate consequences for many patients.

Brain Ischemia↗
PubMed1987

Contrasting effects of 5 alpha- and 5 beta-pregnane-3,20-dione on the motor activity of ovariectomized rats.

While progesterone metabolites have long been known to be potent anesthetics in pharmacological doses, there is no available information as to their effects on behaviour at physiological levels. In this study, 5 alpha- and 5 beta-pregnanediones in silastic capsules were implanted in ovariectomized rats. Approximately 4 mg/kg/day was absorbed over a 24-day period. Rats receiving 5 beta-pregnanedione had decreased motor activity (58% control, P less than or equal to 0.001) while those receiving the 5 alpha-isomer had increased activity (143% control, P = 0.01). These studies suggest that these progesterone metabolites may be responsible for some behavioural changes.

5-alpha-Dihydroprogesterone↗
PubMed1986

Atypical manifestations of pulmonary adenoid cystic carcinoma.

Pulmonary adenoid cystic carcinoma (PACC) typically arises in large airways. A patient who presented with a peripheral lung mass due to PACC is reported. She was found to have multiple pulmonary nodules due to PACC 11 years after resection of the original tumour. We emphasize that 10-15% of patients with PACC present with peripheral tumours.

Carcinoma, Adenoid Cystic↗
PubMed1985

Lay workers in primary health care: victims in the process of social transformation.

The training and utilization of non-professional Primary Health Care Workers (PHCW's) is currently a major strategy for meeting the minimal health needs of the four-fifths of the world's population without permanent access to care. Increasingly, however, in countries where the wealth is in the hands of the few, PHCW's are become victims of political violence. Because the implementation of the Primary Health Care Model in these Third World countries requires a major transformation of the existing socioeconomic structures, the PHCW may be knowingly or unknowingly placed in a vulnerable situation. This relates to the various functions--both latent and manifest--of the PHCW's role as well as to the way they have been trained and utilized. That PHCW's may be utilized as vehicles of a nation's overall political strategy is demonstrated by the role of the 'barefoot' doctors during the cultural revolution in China. In contradistinction, they may be trained and utilized as part of a government's strategy to 'take over' struggling liberation groups and to 'cool out' potentially explosive situations. In addition, they may be used as spies as may their foreign counterparts and trainers. PHCW's trained in programs which encourage health workers to participate with the community in a critical analysis of the root causes of their ill health may be subject to reprisals if, in fact, they actually participate with the community in the development and implementation of strategies designed to combat the underlying social causes of their problems.(ABSTRACT TRUNCATED AT 250 WORDS)

Community Health Services↗
PubMed1984

An interdisciplinary teaching program in geriatrics for physician's assistants.

An interdisciplinary curriculum committee within the Division of Family Medicine, Stanford University Medical Center, developed and taught a beginning course in clinical geriatrics for medical students and student physician's assistants, physical therapists, and nurse practitioners. Through a series of Saturday classes held in community facilities serving seniors, physician's assistant students had the opportunity to learn clinical geriatrics from a faculty team including a physician's assistant, physician, nurse, physical therapist, social worker, gerontologist, and health educator. Local seniors served as consumer consultants and models of health and vigor. This interdisciplinary approach was modeled by the faculty to demonstrate the need for a team approach to deliver quality care to seniors. In this well-received course, the role of the physician's assistant in health care was made evident to their future physician employers and physical therapy co-workers through faculty modeling as well as through informal contacts and patient conferences. Older people constitute a growing and increasingly medically underserved population. Team training may serve to stimulate physician's assistant students to include geriatrics in their career plans while educating their future physician employers about their role.

Curriculum↗
PubMed1984

Evaluation of a sequential 5-FU and hydroxyurea combination in advanced bowel cancer.

Twenty-nine patients (two with small bowel cancer and 27 with colorectal cancer) were treated with a sequential 5-FU-hydroxyurea combination following the suggestion of schedule-dependent synergism in experimental systems. No enhanced toxicity was observed, but the response rate was only 4%. Seven additional patients manifested greater than or equal to 50% declines in CEA, but caution must be used in interpreting such changes as antitumor activity.

Adult↗
PubMed1983

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Humans↗
PubMed1983

Frequency of brain metastasis in adenocarcinoma and large cell carcinoma of the lung: correlation with survival.

From January 1970 through December 1981, 469 patients with histologically or cytologically proven adenocarcinoma (AC) (349) and large cell carcinoma (LC) (120) of the lung were seen at the Department of Radiation Oncology, Medical College of Wisconsin Affiliated Hospitals. One quarter (126/469) of these patients had brain metastasis: 48 patients presented with brain metastasis (AC 35/349 = 10% and LC 13/120 = 11%) and 78 patients subsequently developed brain metastasis (AC 61/314 = 19%, LC 17/107 = 16%). Those patients who received prophylactic cranial irradiation were excluded from this study. Brain was the dominant site of metastasis in 82 patients who received only cranial + thoracic irradiation; 37 patients (17 simultaneous, 20 metachronous) also required irradiation of other sites of metastasis. All 17 patients with LC, and 47/61 (77%) with AC who developed metachronous brain metastasis did so within one year. The cumulative probability of brain metastasis increased with survival to the levels predicted by autopsy studies. Therapeutic brain irradiation may result in long-term survival in patients with single organ brain metastasis. Three of 119 patients who underwent whole brain irradiation for metastasis, are alive at 60 (LC), 48 (AC) and 48 months (AC) after treatment. Since patients with AC and LC so frequently develop brain metastasis and the brain may be the only site of metastasis, prophylactic cranial irradiation may significantly reduce morbidity and mortality from these diseases.

Adenocarcinoma↗
PubMed1983

Purification and characterization of actin from normal and chronic lymphocytic leukemia lymphocytes.

Previous studies from this laboratory have shown actin to be a major protein of human lymphocytes (Stark, R., Liebes, L. F., Nevrla, D., and Silber, R. Biochem. Med., 27: 200-206, 1982). We now report the purification to homogeneity and characterization of actin from blood lymphocytes of normal subjects and patients with chronic lymphocytic leukemia. The recovery of the purified protein was about 20%. The properties of the lymphocyte actins were compared to each other and to those of rabbit skeletal muscle actin. Lymphocyte actin consisted of beta and gamma forms in a 2:1 ratio. The Mr 42,000 was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Normal and leukemic lymphocyte actin had similar polymerization properties as assessed by viscosity measurements at 25 degrees and 4 degrees, and the ultrastructural appearance of the filaments was the same. Similar patterns were observed between normal and chronic lymphocytic leukemia actin tryptic digests analyzed by high-performance liquid chromatography. The Vmax of the actin-activated myosin Mg2+ ATPase activity was compared using rabbit skeletal muscle heavy meromyosin and subfragment 1 preparations. The values obtained with rabbit skeletal muscle and normal lymphocyte actin were identical. The Vmax observed with chronic lymphocytic leukemia lymphocyte actin was 70% of that obtained with normal lymphocyte actin. The amount of actin needed to produce half-maximal activation (Kapparent) of heavy meromyosin and subfragment 1 were, respectively, 26 and 25 microM for normal lymphocytes and 18 and 24 microM for chronic lymphocytic leukemia lymphocytes. The anomalous ATP activation by actin did not reflect differences in B-:T-cell subpopulations between chronic lymphocytic leukemia and normal lymphocytes. The possible significance of the observed differences between the myosin Mg2+ ATPase activation by chronic lymphocytic leukemia and normal lymphocyte actin is discussed.

Actins↗