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Biomedical subjects

J Clark

Publications and source records attributed to J Clark.

At least 361 records · Page 20Linked to original sources
PubMed1986

Phase I study of continuous-infusion cisplatin.

Cisplatin was administered to 21 patients as a continuous infusion over 5 days. Doses of 20, 25, and 30 mg/m2/day were studied. When administered in 3 L of normal saline/day, continuous-infusion cisplatin at a dose of 30 mg/m2/day was associated with neuropathy in two of nine patients and creatinine elevations (greater than 2 mg/dl) in four. No neurotoxicity or nephrotoxicity was observed at lower doses. Severe thrombocytopenia (less than 50,000/microliter) was unrelated to dose and occurred in 19% of the courses. Leukopenia was minimal. Nausea and vomiting were easily controlled. No toxicity was seen in 38% of the courses. Nineteen patients were evaluable for response. Six patients achieved partial response (32%), five had minimal response (25%), and eight had progressive disease (42%) in this group. Seven patients had received cisplatin previously as a bolus treatment (20 mg/m2/day for 5 days) and failed on chemotherapy. Among these patients there was one with partial response, three with minimal response, and three with progressive disease. It is concluded that continuous-infusion cisplatin, as given in this protocol, is well-tolerated at a dose of 25 mg/m2/day and can result in responses in patients failing bolus cisplatin at high doses.

Adult↗
PubMed1985

Prevalence of HTLV-I in Arctic regions.

Sera of native inhabitants of Arctic regions were assayed for antibodies to HTLV-I by the ELISA technique followed by competition experiments to confirm antibody specificity. Residents of 7 widely separated Alaskan villages exhibited prevalence rates of 0 to 12% for HTLV-I antibodies. Less than 1% of Greenland Eskimos were HTLV-I antibody-positive. Residents of 3 northern Swedish regions ranged in HTLV-I antibody prevalence from 0 to 5%. Sera of healthy native inhabitants of Alaska and northern Sweden were similarly assayed for antibodies to HTLV-II. No additional sera were shown to be positive for HTLV-II antibodies. While some of the HTLV-I antibody-positive sera exhibited cross-reactivity with HTLV-II antigens, competition experiments using disrupted HTLV-II or purified HTLV-I p24 as test antigens indicated that the primary antibody response in all cases tested was elicited by HTLV-I. Our results show that HTLV-I distribution is not restricted to endemic areas in warm, humid climates, but extends to Arctic regions. Within these regions, HTLV-I exhibits the same restricted distribution seen in other areas where virus infection is prevalent. The Arctic does not seem to be a reservoir for HTLV-II infection. The origin of HTLV-I in Arctic areas is not known. One may speculate that foreign visitors introduced the virus into Aleut and Lapp populations, and that it has been maintained there and restricted in its distribution as a result of close familial relationships.

Adolescent↗
PubMed1985

Seroepidemiologic studies of human T-cell leukemia/lymphoma virus type I in Jamaica.

The prevalence of HTLV-I antibodies was evaluated in Jamaica among persons with various malignant, infectious, autoimmune and hematologic disorders and in clinically normal persons. Results document that: (1) the prevalence of HTLV-I antibodies in this population increases with age; (2) overall, there is no significant difference in the antibody prevalence between males and females; (3) antibody-positive individuals are born in all major regions of the island and geographical variance in antibody prevalence by place of birth was not prominent; (4) there is further confirmation of the high prevalence of HTLV-I antibody-positive lymphomas in Jamaica; and (5) the prevalence of HTLV-I antibodies in hemophiliacs, patients with chronic lymphocytic leukemia (CLL), myelogenous leukemias, and patients with breast cancer is higher than in the age-matched population without malignancies, although none of these differences were statistically significant. The increased prevalence in hemophiliacs is most likely related to their frequent transfusion with blood products, but it has not yet been determined whether the prevalence in patients with other diseases is related to their diseases or other as yet undefined factors in common.

Adolescent↗
PubMed1985

In great danger.

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Community Health Nursing↗
PubMed1985

The development of a programme for in vitro fertilisation in New Zealand.

The first seven months experience of a programme for in vitro fertilisation at National Women's Hospital in Auckland is described. Following a five month period of technique development, 36 women with tubal infertility were admitted to the programme from July 1983 to February 1984. A clinical pregnancy rate of 15% (6/41 laparoscopies) was achieved during this period.

Abortion, Spontaneous↗
PubMed1985

Bacteriological study of renal calculi.

The pre-operative urine, pelvic urine, removed calculi and calculus washings were examined bacteriologically in 24 patients undergoing removal of intrarenal calculi. Four of seven patients with struvite calculi had an infected pre-operative midstream urine specimen and six of the seven removed calculi demonstrated significant bacterial growth. Proteus mirabilis was the commonest organism isolated. Of 17 patients with oxalate calculi only one had an infected pre-operative urine culture, but in four cases the removed stones were infected. Quantitative bacteriological culture of the stones and their washings demonstrated that infection is within the stone itself. Pre-operative urine culture failed to predict infection within the stone in 60% of patients with infected stones. The results suggest that the presence of infected urine together with the presence of renal calculus is indication for removal of the calculus.

Adult↗
PubMed1985

Metabolism in marine flatfish. II. Protein digestion in Dover sole (Solea solea L.).

The digestive tracts of adult and juvenile Dover sole were examined for protease activities. A pepsin-like protease with an optimal pH value of 1.7 predominated in the stomach region, but the main endoprotease action in the foregut, midgut and hindgut regions was optimal in the range of pH 9.5-10.5 and showed good activity towards elastin orcein. Experiments using synthetic substrates suggested the presence of chymotrypsin- and trypsin-like activities optimal between pH 7 and 8. Collagenase activity was also shown to exist in this pH region. The presence of enzymes corresponding to carboxypeptidases a and b and leucine aminopeptidase was indicated. The possible significance of these results to the farming of Dover sole is discussed.

Animals↗
PubMed1985

Metabolism in marine flatfish--III. Measurement of elastase activity in the digestive tract of Dover sole (Solea solea L.).

A critical assessment of different methods for measuring elastase activity in crude preparations has been made using whole intestinal homogenates of Dover sole. The use of the natural substrate elastin or its dyed derivatives gave optimal pH values in the alkaline region (pH 9.4-9.8) whereas artificial substrates showed optimal hydrolysis nearer neutrality in the region pH 8.1-8.2. Exoproteases may interfere with certain assay procedures. The properties of Dover sole elastase have been further investigated using chromatographic techniques which indicated that the main elastase activity has a molecular weight of approximately 19,500 and an isoelectric point in the region of pH 5.7.

Aging↗
PubMed1985

Recurrent senescence in axenic cultures of Physarum polycephalum.

When subcultures of the aux-2 and aux-4 strains of Physarum polycephalum, which had been grown for more than four years in axenic shake culture, were transferred to non-axenic surface culture they displayed progressively shorter lifespans (older axenic surface cultures yield shorter lived non-axenic cultures). Similar subcultures transferred to axenic agar medium also underwent senescent-like events. These subcultures, after a period of vigorous growth, displayed a slower growth rate, reduced cytoplasmic streaming, loss of yellow pigment, and eventually they fragmented into a number of small spherical structures with the concomitant lysis of most of the plasmodium. In non-axenic culture these structures quickly degenerated (and disappeared from the culture); however, in axenic culture they revived and after several days produced new vigorous plasmodia. Following a period of vigorous growth the plasmodium again underwent senescent-like events. This cycle of senescence and growth was repeated a number of times before death finally occurred.

Cell Cycle↗