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Biomedical subjects

R Silver

Publications and source records attributed to R Silver.

143 records · Page 8Linked to original sources
PubMed1975

Comparative study of cytosine arabinoside therapy alone and combined with thioguanine, mercaptopurine, or daunorubicin in acute myelocytic leukemia.

Three hundred twenty-six patients with acute myelocytic leukemia were randomly and prospectively assigned to four therapeutic regimens: cytosine arabinoside either alone or in combination with daunorubicin, 6-mercaptopurine, or 6-thioguanine. The results in 231 qualified previously untreated patients were analyzed. The combination treatments produced a significantly greater frequency of complete or partial remission than single drug therapy. Treatment with cytosine arabinoside and thioguanine led to 48% age-adjusted complete and partial responses. The median sur survival from diagnosis of all 66 evaluable patients treated with these two drugs was 18 weeks, while the median survival for those who responded to this combination was 15 months.

Adult↗
PubMed1975

Estrogen-progesterone regulation of nest-building and incubation behavior in ovariectomized ring doves (Streptopelia risoria).

The role of ovarian hormones in the induction of nest-building (tucking) and incubation behavior in female doves (Streptopelia risoria) was determined by systemic injections of estrogen, or progesterione, or estrogen combined with progesterone, or oil in reproductively experienced ovariectomized females. Combined estrogen and progesterone treatment was the most effective hormone regimen for eliciting both behavior patterns in females and also facilitated these behaviors in their untreated mates. Differences in role of the gonadal progesterone in male and female doves were discussed.

Animals↗
PubMedDate not supplied

Treatment of early chronic lymphocytic leukemia: intermittent chlorambucil versus observation.

The effect of early therapy on the course of chronic lymphocytic leukemia (CLL) has not been established. Fifty-nine patients with indolent Rai stage I and II CLL were randomized to receive intermittent chlorambucil once a month or to receive no treatment. The two groups were comparable in entry characteristics. At 5 years from randomization there was no significant difference in survival between the two groups although the proportion of patients exhibiting active disease 5 years after randomization is 70 per cent in the untreated group and 55 per cent in the treated group. In this study, early treatment of CLL with intermittent chlorambucil did not result in a survival advantage for patients with indolent stage I and II CLL.

Aged↗
PubMedDate not supplied

A community trial strategy for evaluating treatment for symptomatic conditions.

A method has been developed for simultaneously comparing the usefulness of many treatments of established value for symptomatic medical conditions. Medical assessment of outcome is not employed. Instead patients are required to assess treatments prescribed during the course of ordinary general practice rather than under the strictly controlled settings of most clinical trials. Outcome incorporates patient compliance and treatment acceptability and is based on patients' subjective judgments of the usefulness of randomly allocated treatments as recorded in self-completed diaries, which are mailed directly to a trial centre. Thus large and more representative samples are achieved through minimizing the efforts required, both of participating doctors and of patients. Although the approach was originally developed and tested for the comparison of hay fever treatment regimens, we believe that it can be adapted to compare many other treatments where patient-reported symptoms validly describe the outcome of interest. The feasibility of the approach was tested in two pilot studies, and it has been employed successfully in a two-year trial comparing seven hay fever treatments. Aspects of analysing such trials are discussed.

Clinical Trials as Topic↗
PubMedDate not supplied

Lithium lengthens the period of circadian rhythms in lesioned hamsters bearing SCN grafts.

Lithium lengthens the free-running period of circadian rhythms in a wide variety of organisms. The object of the present study was to examine the effects of lithium treatment on free-running activity rhythms in suprachiasmatic nuclei lesioned (SCN-X) hamsters that had recovered circadian rhythmicity following transplantation of fetal anterior hypothalamic grafts containing the suprachiasmatic nuclei (SCN). The animals were housed individually in cages equipped with running wheels, and locomotor activity was monitored using a computer-based data acquisition system. At the end of the behavioral tests, animals were anesthetized and perfused. Brain sections were immunostained for vasoactive intestinal peptide (VIP) and vasopressin-associated neurophysin (NP) to evaluate the extent of the lesion and the presence of a functional graft. In both intact and in SCN-X grafted animals, lithium lengthened the period of free running activity without affecting the amount of activity or the precision of the rhythm.

Animals↗
PubMedDate not supplied

Gender differences and the outcome of interventions for acute coronary syndromes.

Differences in the overall mortality for acute infarction in women vs men have been appreciated for some time. Some of these differences are based on the age at the time of presentation of women compared with men. Excess mortality in women is most clear at the younger end of the age spectrum. More careful examination of the data has shown differences based on factors such as greater delays in presentation in women, real biases in the types of healthcare provider, and selection of diagnostic and therapeutic interventions for women compared with men. Recently, the mode of presentation has emerged as a major defining point. Women present more frequently with unstable angina or non-Q-wave infarction and have lesser mortality with these syndromes compared with men. Thus, the overall outcomes of acute coronary syndromes vary substantially from the differences in outcome for acute Q-wave infarction alone. New data have emerged regarding differences in treatment outcome for acute infarction. Women have derived lesser benefit from thrombolytic therapy and still respond to percutaneous transluminal coronary angioplasty more favorably than thrombolytic therapy for acute infarction. Women seem to have less benefit from stent use compared with angioplasty alone for acute infarction. Although increasing scrutiny has shed a great deal of light on some of these gender differences in outcomes from acute coronary syndromes, a real difference in mortality for younger women remains unexplained. The basis for real differences in outcome with the use of various therapies for acute infarction, such as thrombolysis and stent use, are also not well elucidated.

Angioplasty, Balloon, Coronary↗
PubMedDate not supplied

Dipyridamole decreases platelet-derived growth factor levels in human serum.

Mitogenic activities on confluent fibroblasts by sera from patients with scleroderma and normal controls were studied. In experiments using eight different fibroblast strains (one human fetal lung fibroblast, one foreskin fibroblast, three adult skin fibroblast, and three scleroderma fibroblast), pooled scleroderma serum showed lower mitogenic activity by 3H-thymidine incorporation assay than pooled normal serum. Individual serum investigations revealed that 11 of 33 patients (33%) showed low mitogenic activities; all 11 patients were receiving dipyridamole. Of 15 patients, 11 (73%) receiving dipyridamole showed low mutagenic activities; none of 18 patients not receiving dipyridamole showed low mitogenic activities. Approximately 70% of this serum activity was inhibited by the addition of anti-platelet-derived growth factor (PDGF) antibody indicating that most of this serum activity seemed to be derived from PDGF. Western blot analysis of extracts of normal sera before and after administration of dipyridamole with antihuman PDGF antibody showed a large decrease in the amount of immunoreactive PDGF present. These data indicate that dipyridamole is an effective drug to lower release of PDGF during blood clotting.

Adult↗
PubMedDate not supplied

How do fetal grafts of the suprachiasmatic nucleus communicate with the host brain?

Fetal grafts containing the hypothalamic suprachiasmatic nucleus (SCN), the site of an endogenous circadian pacemaker, can reinstate behavioral rhythms in lesioned recipients but the precise routes of communication between the graft and the host brain remain unknown. Grafts containing the SCN may convey temporal information to the host brain via neural efferents, diffusible factors, or a combination of both. We examined graft-host connections in anterior hypothalamic homografts (hamster-to hamster) and heterografts (rat-to hamster) implanted in the third ventricle by: (a) applying the carbocyanine dye, diI, directly onto homo- and heterografts in fixed tissue sections; and (b) using a donor-specific neurofilament (NF) antibody to immunocytochemically visualize heterograft efferents. DiI applied onto either homografts or heterografts labeled relatively few graft efferents which could be followed only short distances into the host brain. In contrast, NF-labeled heterograft efferents were both more numerous and extended for longer distances into the host brain than anticipated on the basis of diI tract tracing. The results suggest that anterior hypothalamic grafts implanted in the third ventricle provide substantial input to the adjacent host hypothalamus although it is not known whether these projections arise from SCN cells or from other extra-SCN hypothalamic tissue within these grafts. Nor is it known whether these projections are functional. To determine if neural efferents are required for the restoration of rhythmicity after grafting, we have encapsulated fetal anterior hypothalamus in a permselective polymer which prevents neurite outgrowth but allows diffusible signals to reach the host brain.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Plasma erythropoietin in health and disease.

Erythropoietin is a hormone produced by the kidneys and by certain extrarenal tissues and released into the circulation in response to tissue hypoxia. Its study has provided new information about oxygen transport and bone marrow stem cell function and its determination in plasma can give valuable diagnostic clues as to the etiology and pathogenesis of anemias and polycythemias. The various methods used for such measurements are discussed, and it is recommended that the in vivo bioassay in polycythemic mice be utilized until a workable radioimmune assay has been perfected. The results with the use of this in vivo bioassay to measure plasma erythropoietin in patients with uncomplicated anemia, aplastic anemia, anemia of renal disease, anemia of chronic inflammatory or neoplastic disorder polycythemia vera, and secondary polycythemia are charted and their diagnostic significance discussed.

Anemia↗
PubMedDate not supplied

Insult after injury: pressure ulcers in trauma patients.

DESIGN: Nonexperimental-Descriptive. SAMPLE: The inclusion criteria were trauma patients, ages 15 and older, who were hospitalized for > 2 days, and who did not have preexisting skin breakdown. A total of 148 consecutive trauma patients admitted to the study institution meeting the inclusion criteria were prospectively enrolled. METHODS: Patients were assessed every 3 days for skin breakdown. Information on the patient's bed type, therapies, medical devices, and nutrition was collected. The Braden Scale for predicting pressure ulcer risk was completed at each assessment. FINDINGS: Of the 148 patients enrolled, 30 developed at least one area of skin breakdown for a prevalence of 20.3% in patients hospitalized more than 2 days. The most common cause of breakdown was positional pressure (47.4%). Cervical collars were the second leading cause at 23.7%, followed by tracheostomy/endotracheal tubes at 10.5%. The mobility subscale of the Braden Pressure Ulcer Risk Assessment tool was significantly predictive of skin breakdown (p < .001). IMPLICATIONS FOR NURSING RESEARCH: Skin breakdown is a significant problem in trauma patients who are hospitalized for more than 2 days. Aggressive protocols on positioning, cervical collar use, and airway adjuncts, as well as additional active nursing interventions for immobile patients, may be ways to decrease the skin breakdown prevalence in this population.

Adolescent↗