Search PubMed⌕ Search

Biomedical subjects

G Greenberg

Publications and source records attributed to G Greenberg.

At least 55 records · Page 3Linked to original sources
PubMed1984

Effects of diuretic and beta-blocker therapy in the Medical Research Council Trial.

The Medical Research Council's treatment trial for mild hypertension was designed to determine the effects of blood pressure reduction on cardiovascular morbidity and mortality rather than to compare the separate effects of thiazides and beta-adrenergic blocking agents. However, the simultaneous use of both active treatments was discouraged and comparisons in terms of blood pressure control, adverse drug reactions, and drug-related changes in the serum biochemistry are possible. The net differences in systolic and diastolic pressure between treated and control subjects were greater in older than in younger people; this net difference was more pronounced in the older people assigned at random to receive bendrofluazide as opposed to propranolol; this effect increased with time during the trial. The need for a supplementary drug (methyldopa) to control blood pressure at target level, was greater in the thiazide-treated group for all ages. Withdrawal from randomized treatment due to adverse reactions was greater in men receiving bendrofluazide than in those receiving propranolol, and greater for women receiving propranolol than in those receiving bendrofluazide. Thiazide treatment was shown, in a sub-study, to be associated with a significant increase in ventricular ectopic activity in long-term participants.

Adult↗
PubMed1984

Dream dimension differences during a life change.

Dreams reported from laboratory awakening of stably married women differed from those of women undergoing divorce: The former dreamed of the experiment; the latter had more threat themes. Those coping well during the divorce had more positive motives in the last dream than those who were depressed. Dreams of the nondepressed divorcées increased in anxiety from first to last dream report, whereas those of the depressed increased in masochism. Affiliation motives were common in dreams of the married subjects, while harm avoidance predominated in the divorcées' dreams. Nurturance and abasement were also common needs in the dreams of the depressed sample.

Adaptation, Psychological↗
PubMed1983

A novel cell-to-cell interaction between mast cells and other cell types.

Time-lapse cinephotomicrography and transmission electron microscopy (TEM) have been used to study the interactions between rat mast cells and different cell monolayers in culture (fibroblasts, vascular endothelial cells and cardiac muscle cells). This report documents a novel form of behavior between mast cells and certain other cell types. We have tentatively termed this cellular behavior 'transgranulation', which involves sequential changes not seen in control cells, including: (1) formation of a granule-containing mast cell pseudopod that becomes closely applied to an adjacent cell; (2) development of specialized plasma membrane interrelationships between apposing cells; (3) alteration of granules and perigranular membranes within the mast cell pseudopod; (4) occasional transfer of exocytosed mast cell granules to the cytoplasm of the adjacent cell; (5) presence of a specialized inclusion body in the mast cell; and finally, (6) either withdrawal of the pseudopod by the mast cell, or casting-off of the pseudopod from the mast cell, leaving it on the surface of the adjacent cell (pseudopod translocation). These mast cell interactions occur specifically with fibroblasts and endothelial cells in vitro and are never observed with cardiac muscle cells or non-cellular substrates. Our investigations of rat mesenteries in situ confirm that these cell-cell interactions also occur in vivo. We suggest it represents a form of cell-to-cell communication involving secretion from a mast cell pseudopod to another cell type. The significance of specialized contacts between mast cells and other cell types in vivo is discussed.

Animals↗
PubMed1983

The epithelial genotype controls the pattern of extracellular enamel prism formation.

Enamel formation in the developing tooth organ is the product of epithelial-mesenchymal interactions which result in the differentiation of ameloblasts, the secretion of enamel proteins, and the production of a highly organized extracellular matrix. The three-dimensional organization of enamel prisms is species-specific: irregular polygon-shaped in rabbit and rectangular-shaped in mouse. We designed experiments to test the hypothesis that three-dimensional organization of enamel prism formation is genetically determined by epithelium; the prediction being that species-specific enamel prism pattern formation is expressed independent of mesenchymal instructions. Our strategy employs scanning electron microscopy to examine enamel prism patterns formed during rabbit and mouse tooth morphogenesis in situ and in vitro, and to then determine the specific tissue type required for regulating these patterns using heterotypic tissue recombinations. Morphometric analyses demonstrated that cap stage tooth organs cultured on the chick chorioallantoic membrane (CAM) formed enamel prisms equivalent to prism patterns observed for in situ controls. Heterotypic tissue recombinations, using cap stage molar organs, formed rabbit-like prisms with rabbit epithelium/mouse mesenchyme, and mouse-like prisms with mouse epithelium/rabbit mesenchyme. These results indicate that dental papilla mesenchyme has no apparent influence on enamel prism pattern formation. Enamel prism pattern appears to be genetically regulated by the inner enamel epithelium.

Animals↗
PubMed1982

Seasonal variation in arterial blood pressure.

Blood pressure measurements recorded during the medical Research Council's treatment trial for mild hypertension have been analysed according to the calendar month in which the readings were made. For each age, sex, and treatment group systolic and diastolic pressures were higher in winter than in summer. The seasonal variation in blood pressure was greater in older than in younger subjects and was highly significantly related to maximum and minimum daily air temperature measurements but not to rainfall.

Adult↗
PubMed1982

Logistics and management of clinical trials.

This chapter is concerned with some of the more mundane aspects of the day to day design, planning, documentation, and management of clinical trials, rather than with the finer points of trial design which are dealt with in detail elsewhere. The points considered here, taken individually, seem obvious and trivial but it is hoped that some may be helpful in obtaining the maximum return for the work invested in running a trial.

Clinical Trials as Topic↗
PubMed1980

Progestogens and cardiovascular reactions associated with oral contraceptives and a comparison of the safety of 50- and 30-microgram oestrogen preparations.

Progestogens probably have metabolic effects that may contribute to the increased risk of cardiovascular reactions associated with combined oestrogen-progestogen oral contraceptives. This possibility was investigated by a study of nearly 2000 reports to the Committee on Safety of Medicines from 1964 to 1977. The reports concerned preparations in which norethisterone acetate in doses of 1.0, 2.5, 3.0, or 4.0 mg was combined with 50 microgram of ethinyloestradiol and those in which levonorgestrel in doses of 150 or 250 microgram was combined with 30 microgram of ethinyloestradiol. Observed and expected numbers of reports were compared, using retail pharmacy purchase figures as a measure of the use of different preparations. There was a significant positive association between the dose of norethisterone acetate and deaths from stroke and ischaemic heart disease (IHD); this association was also found for all cases of these two conditions, fatal plus non-fatal. There were no associations of dose of norethisterone acetate with hypertension or venous thrombosis. The higher dose of levonorgestrel was associated with a possible excess of deaths, non-venous plus venous, and an excess of strokes. There was no association between dose of levonorgestrel and hypertension or venous thrombosis. The reports were also used to assess the relative safety of 30-microgram and 50-microgram oestrogen preparations. Those with 30 microgram of oestrogen were associated with significantly fewer reports of death and IHD (both fatal, and fatal plus non-fatal) than those with 50 microgram of oestrogen. In view of the large-scale move towards preparations with progressively lower oestrogen doses, there are no grounds for major changes in oral contraceptive practice. Within the range of preparations currently in use, however, there is a case for minimising the dose of progestogen to reduce the chances of thromboembolism.

Cardiovascular Diseases↗
PubMed1980

Liposarcoma metastatic to bone marrow presenting as myelophthisic anemia: a case report.

A case report of liposarcoma occurring in a man with probable hereditary multiple lipomata and metastasizing to bone marrow is presented. The neoplasm was studied by light and electron microscopy. The first evidence for metastatic disease was myelophthisic anemia. This unusual clinical occurrence is discussed briefly in conjunction with other neoplasms causing myelophthisis.

Anemia, Myelophthisic↗
PubMed1980

High cancer mortality rates from childhood leukemia and young adult Hodgkin's disease and lymphoma in the New Jersey-New York-Philadelphia Metropolitan Corridor, 1950 to 1969.

In comparison to the United States as a whole and to their total population age-adjusted rates, the New Jersey-New York-Philadelphia Metropolitan Region was found to have excessively high childhood leukemia and high young adult Hodgkin's disease and lymphoma cancer mortality rates in the period from 1950 to 1969.

Adolescent↗
PubMed1979

The effect of bacterially produced vitamin B12 analogues (cobamides) on the in vitro absorption of cyanocabalamin.

An incubation system containing rat jejunoileum was used to determine whether analogues of cyanocabalamin (CNCbl) inhibited the in vitro absorption of CNCbl. The naturally occurring analogues "pseudo B12," "factor A," and the nonnaturally occurring analogue desdemethyl B12, were produced by guided biosynthesis with Propionibacterium arabinosum. Factor B was produced by acid cleavage of cyanocabalamin. Inhibition of Co57-CNBbl uptake was demonstrated for cold CNCbl and for desdemethyl B12, although statistical significance was achieved only for cold CNCbl at 40X and 100X the molar quantity of the radiolabeled CNCbl. However, a trend towards progressive inhibition of specific CNCbl binding was shown as increasing concentrations of CNCbl or desdemethyl B12 were used. No inhibition of specific CNCbl binding could be demonstrated for any of the naturally occurring cobamides tested.

Animals↗
PubMed1978

Intramuscular injections of iron compounds and oncogenesis in man.

To evaluate the evidence for iron compounds as local carcinogens in man, histological material and clinical reports have been reviewed in seven of the eight published cases of tumours developing at the site of intramuscular injections. The microscopical appearances suggested benign lesions in two cases and a variety of tumours in the other five. In only two cases (a rhabdomyosarcoma and a fibrosarcoma) was the interval between injections and tumour development longer than six years. Of the remaining three tumours, one was considered to be a rather slowly growing haemangiopericytoma (with an interval of two years), one appeared to be a subcutaneous lymphoma with no evidence of having arisen in the gluteal muscles, and one was a pleomorphic sarcoma with a possible five-year interval. Sarcomas induced experimentally by iron compounds differ in being less variable in type and in containing abundant iron-containing macrophages, which were negligible in these human tumours.Although the total number of patients who have received intramuscular injections of iron compounds is not known, the present findings, in contrast to experimental work, do not support the view that such treatment carries a strong risk of tumour development.

Adolescent↗
PubMed1978

Failure to observe visual discrimination in old gerbils: replication report.

A recent study showed that while young gerbils can learn a visual line discrimination task, old gerbils cannot. That study has been criticized for not equating the motivational levels of the two age groups. The present study attempted to answer that criticism. Accordingly, two groups of old gerbils (total N = 10) were motivated either by a 22 hour food deprivation schedule or an 80% reduction in their ad lib weight. All animals were tested in a T-maze with sunflower seed reinforcers (highly prized by gerbils) being associated with horizontal or vertical stripes. As in the earlier study, these old gerbils did not acquire the visual discrimination.

Aging↗
PubMed1977

Maternal drug histories and congenital abnormalities.

We obtained drug histories for the first trimester of pregnancy for 836 mothers of congenitally malformed babies and for an equal number of control mothers of normal babies from the same doctors' practices. There was an association between the use of a hormonal pregnancy test and the subsequent birht of a malformed baby. There was also a greater use of barbiturates by mothers of affected children compared with mothers of control babies, mainly accounted for by treatment of epileptic mothers with phenobarbitone. For all other drugs usage was similar in both sets of mothers.

Abnormalities, Drug-Induced↗
PubMed1976

Visual discrimination in the Mongolian gerbil (Meriones unguiculatus) as a function of age.

Ten young (8 weeks) and 10 old (26 weeks) male gerbils were tested for the acquisition of a visual discrimination task. Ss were given 10 daily six-trial sessions in a T-maze with a food reinforcement being associated with horizontal or vertical stripes. The older Ss failed to learn the discrimination habit, and the young Ss steadily improved over the 10 sessions.

Age Factors↗