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Biomedical subjects

L Newcomer

Publications and source records attributed to L Newcomer.

7 recordsLinked to original sources
PubMed2000

Managed care companies and the practice of medicine.

One of the major issues pertaining to the pending legislation for Patient's Bill of Rights is the potential of liability health care plans, particularly when they decline coverage they consider not medically necessary. We call these contracts "managed health care" plans. But, realistically, when is it managing? When is it medicine? When, if at all, does management undermine medicine? And if it does, should managed care organizations--and their representatives--be held legally liable for medical decisions that go wrong? A panel of seven experts examines these questions from medical, payment, patient, legal, insurance, and governing viewpoints.

Clinical Trials as Topic↗
PubMed1992

Anticardiolipin antibodies and the risk for ischemic stroke and venous thrombosis.

OBJECTIVE: To determine whether the presence of anticardiolipin antibodies is a risk factor for ischemic stroke and venous thrombosis in healthy adult men. DESIGN: A nested, case-control study in a prospective cohort. SETTING: A nationwide study of physicians. PARTICIPANTS: The study sample was drawn from the Physicians' Health Study, a randomized, double-blind, placebo-controlled trial of aspirin and beta-carotene in 22,071 male physicians. At entry, 68% of the participants submitted plasma samples that were subsequently frozen at -80 degrees C. During 60.2 months of follow-up, follow-up for nonfatal outcomes was 99.7% complete and ascertainment of fatal outcomes was 100% complete. We identified men with documented ischemic stroke, deep venous thrombosis of the leg, or pulmonary embolus and for whom a plasma sample was available. A control was matched by age, smoking history, and length of follow-up to each of the 100 patients with ischemic stroke and the 90 patients with deep venous thrombosis or pulmonary embolus. MEASUREMENTS: Plasma samples were assessed for IgG anticardiolipin antibodies by enzyme-linked immunosorbent assay. The mean anticardiolipin antibody titers of the case patients in the two diagnostic groups (ischemic stroke; venous thrombosis or pulmonary embolus) were compared with those of the control groups, and relative risks were calculated for patients in increasing percentile categories of anticardiolipin antibodies by conditional logistic regression. RESULTS: The anticardiolipin antibody titers were higher in case patients with deep venous thrombosis and pulmonary embolus than in their matched controls (P = 0.01). Persons with anticardiolipin antibody titers above the 95th percentile had a relative risk for developing deep venous thrombosis or pulmonary embolus of 5.3 (95% CI, 1.55 to 18.3; P = 0.01). The anticardiolipin antibody titers in case patients with ischemic stroke and controls were not significantly different (P > 0.2), and no clear trend of higher risks among those with elevated levels of anticardiolipin antibodies was observed. CONCLUSION: An anticardiolipin antibody level above the 95th percentile is an important risk factor for deep venous thrombosis or pulmonary embolus but not for ischemic stroke in healthy adult men.

Adult↗
PubMed1986

Influence of exercise training on maternal and fetal morphological characteristics in the rat.

Evidence in both humans and animals has shown that exercise before or during pregnancy may effect fetal outcome. The purpose of this investigation was to examine the effects of an exercise program on fetal development in the rat. Prior to impregnation one group of animals was exercise-trained on a Quinton shock-stimulus rodent treadmill. The exercised group was trained to run 5 days/wk, for 2.0 h/day at 31 m/min up an 8 degree incline for 8 wk before mating. Following mating the training intensity was reduced to 27 m/min up a 5 degree incline, and the exercise period decreased to 1 h/day. On day 19 of gestation, 24 h postexercise for the trained mothers, the animals were killed in the fed state and the maternal and fetal characteristics were measured. The sedentary controls gained significantly (P less than 0.05) more body weight during pregnancy. This can be attributed to three factors: higher number of fetuses, 14.83 +/- 0.04 vs. 12.2 +/- 0.85 for the trained; larger litter weights, 44.25 +/- 4.97 vs. 26.17 +/- 1.82 g/dam for the trained; and slightly larger lipid stores. In addition to having fewer pups the trained mothers had a greater number of fetal resorptions; 0.9/dam as opposed to 0.17/dam for the sedentary control. Analysis of fetal body composition showed no difference in total body water, protein, or fat between the pups of sedentary and trained dams. The results of this study indicate that exercise training prior to and during pregnancy influences fetal development in the rat.

Animals↗
PubMed1984

Thymidine enhancement of methotrexate and 5-fluorouracil toxicity in cultured human colon carcinoma.

Cultures of human colon carcinoma, HCT-8, were treated with millimolar concentrations of thymidine by different schedules designed to cytokinetically and biochemically modulate methotrexate (MTX) and 5-fluorouracil (FUra) toxicity. Thymidine (dThd)-synchronized HCT-8 cells monitored by flow cytofluorometry showed increased sensitivity to MTX and synergistic cytotoxicity to the combination MTX-FUra. FUra toxicity in synchronized cells showed no significant phase specificity overall, but a pattern of relative G2/M resistance was correlated with decreased intracellular FUra accumulation, incorporation into RNA, and formation of FdUMP. In asynchronous cultures dThd reduced MTX toxicity when given within the first 12 h of a 24-h MTX exposure, and also appeared to reduce the MTX-induced synergistic enhancement of FUra toxicity. When dThd was administered with FUra alone in asynchronous cultures, progressive, and synergistic enhancement of FUra toxicity was observed only after 6 h dThd pretreatment. Unlike MTX-FUra synergy, this schedule-dependent synergism between dThd and FUra did not correlate with intracellular FUra accumulation or specific incorporation into total cellular RNA. These results suggest that less well studied mechanisms of dThd modulation, other than enhanced deoxynucleotide formation or total RNA incorporation, may biochemically enhance FUra toxicity in HCT-8 cells.

Cells, Cultured↗
PubMed1984

Acute cardiorespiratory responses of hypertensive rats to swimming and treadmill exercise.

The acute cardiorespiratory responses of spontaneously hypertensive rats (SHR) to swimming and running exercise was investigated because SHR populations are hyperresponsive to external stimuli, of the paucity of existing data, and of the uncertainty on the role of exercise stimuli for training adaptations to occur. Male rats were assigned to one of five groups (n = 5-6/group) and designated as controls (C), inexperienced or naive free swimmers (NFS), experienced free swimmers (FS), experienced weighted swimmers (WS) (attached weights equal to 2% of their body weight) or experienced runners (R) who ran at an intensity of 75% of their VO2max. After 75 min in the water, all groups were acidotic and hypercapnic with the WS experiencing the greatest changes. Heart rate (HR) was increased in all swimmers during the initial 10 min, but declined thereafter, and after 75 min, the HR of WS (348 +/- 1 beats/min) was significantly lower than the C group (416 +/- 22 beats/min). At the same time interval, mean arterial blood pressure (MAP) was decreased in all swimming groups to values lower than the C animals. In addition, an exaggerated diving reflex was frequently noted when the rats were submerged. When the magnitudes of the changes were evaluated in the swimming animals they were directly associated with their submergence times, i.e., during 65-75 min of the swim, NFS, FS, and WS were submerged for 43, 46, and 66% of their total swim time, respectively. In sharp contrast to the swimmers, the runners exhibited increases in HR and MAP with their blood gas measurements being indicative of hyperventilation. We concluded that swimming as an exercise mode for hypertensive rats is best served to study the combined effects of excitement, prolonged submergence, and the consequences of the diving reflex.

Animals↗