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Biomedical subjects

L Green

Publications and source records attributed to L Green.

At least 271 records · Page 15Linked to original sources
PubMed1980

Self-initiated, cue extinction, and covert sensitization procedures in smoking cessation.

Two studies tested the utility of self-control procedures and covert sensitization as alternatives to rapid smokers in smoking cessation. Subjects were at least 21 years old and had smoked at least one pack per day for at least 5 years. Relaxation training and discussion of goals were given in three meetings per week for 2 weeks prior to subject-chosen quit dates. A total of 10 sessions was held during the 90 days following cessation. In Study I, both groups received self-control strategies. One group also received covert sensitization. At 3-month follow-up, 33% of those without and 27% of those with covert sensitization were abstinent. At 6-month follow-up these percentages were 33 and 13, respectively. Covert sensitization apparently added nothing to the effects of the self-control package. In Study II, one group received the same combination of self-control manual and the basic package as in Study I. A second group received the basic package with cue extinction procedures designed to extinguish associations between desires for cigarettes and cues paired with previous smoking. A third group received a combination of both sets of procedures. At 3-month follow-up, 71 and 60%, respectively, of the first two groups were abstinent, while only 31% of the combination group was abstinent. At 6-month follow-up, these percentages were 29, 27, and 8, respectively. The low abstinence rate for the combination group likely reflects problems associated with presenting too much material in the 2 weeks prior to cessation.

Adult↗
PubMed1980

A hierarchical organization of blood pressure during natural behaviour in rat and the effects of central catecholamine neurons thereon.

1. Changes in arterial pressure associated with a repertoire of natural behaviour patterns in the rat were examined. 2. A hierarchy of such changes was found. Eating and drinking were associated with higher pressures than grooming and exploration, which in turn were associated with higher pressures than resting. 3. Desynchronized sleep was associated with higher pressures than slow-wave sleep. 4. Lesions of the catecholamine neurons of the A2 region of the medulla did not disrupt the normal hierarchy but resulted in an exaggerated pressor response.

Animals↗
PubMed1980

Genetic mapping of the Salmonella typhimurium pepB locus.

Transposon technology has been used to map the pepB locus of Salmonella typhimurium. This locus is cotransducible by phage P22 with glyA and strB at min 56 on the Salmonella genetic map. The gene order is strB pepB glyA.

Aminopeptidases↗
PubMed1980

Choice between rewards differing in amount and delay: Toward a choice model of self control.

A concurrent-chain procedure was used to study pigeons' choices between rewards differing in both amount and delay. The shorter delay terminated with a 2-second access to grain whereas the longer delay terminated with a 6-second access to grain. The ratio of the delays was constant within a given condition while their absolute values were varied. Over conditions, ratios of 6:1, 3:1, and 3:2 were studied. As the absolute values of the delays to reinforcement increased, preference for the longer-delayed but larger reward decreased under both the 6:1 and 3:1 ratios, but increased under the 3:2 ratio. These results are inconsistent with choice models predicting no change in preference when the ratios of delays and amounts are held constant. In addition, the change in preference under the 3:1 ratio is inconsistent with a simple multiplicative interaction of the trade off between reinforcer amount and delay, and suggests that delay is a more potent determinant of choice than is amount. These results have implications for models that view choice between small immediate rewards and large but delayed rewards as underlying the behavior commonly called self control.

Journal Article↗
PubMed1980

Second-order conditioning of the pigeon's key-peck using an autoshaping procedure.

Second-order conditioning of the pigeon's key-peck was established using an autoshaping procedure. In the first experiment, pigeons came to peck a response key, the second-order conditioned stimulus (CS2), when it was paired with another key (CS1) that had previously been paired with food delivery. In the second experiment, pigeons again came to peck a key (CS2) when it was followed by a clicker (CS1) which had been paired with food delivery, even though the clicker itself had not evoked pecking. Responses to a second-order stimulus, therefore, need not resemble responses to the first-order CS. Furthermore, in both experiments, extinction of the first-order IS led to reduction in pecking CS2. These results were discussed in terms of the nature of the associations being formed during second-order conditioning.

Animals↗
PubMed1979

Inappropriate coronary vasoconstriction in patients with coronary artery disease: a role for nifedipine?

Coronary arterial vasoconstriction, well recognized in Prinzmetal's variant angina, may participate in the pathogenesis of classic angina as well. Several recent studies in patients with obstructive coronary artery disease suggest that apparently spontaneous reductions in coronary blood flow can result in myocardial ischemia and even infarction. Evidence supporting the alpha adrenergic nervous system as a cause of such coronary vasoconstriction is reviewed, particularly the results of provocative testing with the cold pressor stimulus. Upon exposure of the skin to cold, patients with coronary artery disease demonstrate an inappropriate coronary vasoconstrictor response, often sufficient to produce angina. Normal patients, by contrast, show no change in coronary vascular resistance. In patients with a diseases coronary circulation, inappropriate vasoconstriction further restricts myocardial perfusion and appears to be little affected by beta adrenergic blocking agents or nitrates in the usual dosages. Nifedipine has proved effective in preventing coronary arterial spasm in patients with Prinzmetal's angina. Studies currently in progress suggest that it is also effective in blocking inappropriate coronary vasoconstriction in patients with typical angina. Nifedipine may thus be a useful addition to the treatment of ischemic heart disease.

Angina Pectoris, Variant↗
PubMed1979

Estrogen receptor values in patients with benign breast disease.

Tissue specimens from 55 female patients with benign breast disease were assayed for estrogen receptor. Twenty-one of 55 patients (38%) had tumors which contained significant amounts of estrogen receptor (greater than 10 femtomoles/mg protein). Fibroadenomas possessed estrogen receptor more frequently than fibrocystic disease or other benign breast tumors. Estrogen receptor positivity did not correlate with laterality of the tumor; location or size of the largest nodule. Patients with estrogen receptor positive tumors had a mean age of 26.9 years compared to 36.4 years for patients with estrogen receptor negative tumors (p less than 0.01). Twenty of 46 (43%) premenopausal patients had benign tumors which were estrogen receptor positive compared to zero of 8 postmenopausal patients (p less than 0.05).

Adenofibroma↗
PubMed1979

In vitro nitrosation of methapyrilene.

The reactions of sodium nitrite and methapyrilene were studied in aqueous solution at neutral pH and under simulated gastric fluid conditions. Reaction product formation was much more complex than nitrosation of the parent molecule dimethylamino moiety to form nitrosodimethylamine. Several new nitroso compounds were formed under the reaction conditions studied. The simultaneous incorporation of 2 moles of ascorbic acid/mole of nitrite ion prevented any destruction of methapyrilene under all conditions studied. The implications of these observations with respect to nitrosation theory, the general carcinogenicity of nitroso compounds, and methapyrilene dosage formulation are discussed.

Aminopyridines↗
PubMed1979

Phase-II trial of tamoxifen in advanced breat cancer.

Seventy-eight advanced breast cancer patients, most of whom had had prior treatment, were treated with the synthetic antiestogen tamoxifen. The overall objective response rate was 27% (21/78). An additional 19% (15/78) showed disease stabilization. Sixty-seven percent (14/21) of the responses were in soft tissue sites, 24% (5/21) on bony sites and one each occurred in liver and nodular lung disease. Forty percent of patients with soft-tissue disease alone responded, while less than 10% of patients with visceral disease showed responses in visceral sites. The response rate was 28% among patients with a known positive estrogen receptor (ER) assay. It was 21% among patients who had previously received cytotoxic drugs. Toxicity was mild and was seen in nausea and vomiting, hot flushes and vaginal bleeding, and occasional myelosuppression. One patient was withdrawn from the study because of a rash. In two patients the disease flared, once with concomitant hypercalcemia. Tamoxifen is a useful agent for advanced breast cancer even in some patients with visceral disease.

Adenocarcinoma↗
PubMed1979

Serum immunoglobulins G, A, M, D and E concentrations in lymphomas.

Serum immunoglobulin levels were measured in 105 patients with untreated Hodgkin's disease (HD) and 80 with non-HD lymphomas. Significant increases in IgG and IgE occurred in the whole HD group. When compared with the histological types of HD, increases of IgG, IgA AND IgE were seen in nodular sclerosis and of IgE alone in mixed-cellularity and lymphocyte-predominant types. In relation to the stage of disease spread, increases of IgG, IgA AND IgE occurred in Stages II and III, while in Stage IV, although IgE was raised, IgM in males and IgD fell significantly. Paired serum samples taken 10-14 months apart showed falls of IgM and IgD after radiotherapy, and of all Ig classes except IgD after chemotherapy. Decreased levels of IgM in females, IgG and IgA were found in the non-HD lymphomas. When analysed in terms of lymphnode histology, decreased IgG, IgA, IgM and IgE occurred in well differentiated lymphocytic lymphomas, decreased IgA alone in poorly differentiated lymphocytic lymphomas and decreased IgD in nodular types of lymphoma.

Adolescent↗
PubMed1979

Some properties of site-specific and general recombination inferred from int-initiated exchanges by bacteriophage lambda.

The site-specific recombination at the attachment site for prophage integration might proceed by two general mechanisms: (1) a concerted reaction without a free intermediate; (2) a sequential mechanism differing from typical general recombination only by an inability of the cross-strand intermediate structure to migrate into the region of nonhomology adjacent to the attachment site. The blocked-migration model predicts frequent genetic exchange in the int xis region near the attachment site if Int-mediated recombination occurs between lambda phage with homologous attachment sites. We find such additional int xis exchanges, but only at very low frequency (1% of the Int-mediated recombination). We conclude that the resolution point only rarely moves away from the initial crossover point specified by Int and, therefore, that the Int reaction is mainly concerted. We interpret the rare additional int xis recombinants as indicative of occasional branch migration from an initial Int-mediated crossover. The frequency of the rare int xis recombinants is not simply related to distance from the attachment site to an int- or xis- mutation, suggesting that the heteroduplex distance is often at least a gene in length. The frequency of these additional exchanges is also not a strong function of distance between two mutations; from this we conclude that the resolution to the observed recombinant structure in the sequential cases occurs often by mismatch repair. We have found no marked effect of mutations in the bacterial recA, recB, recC, recF, or recL genes on the frequency of the int xis recombinants; this may indicate that none of these genes specifies a product uniquely required for resolution of a cross-strand intermediate.

Bacteriophage lambda↗
PubMed1979

Immunopathological changes in cadmium-treated rats.

Rats treated with cadmium developed an interstitial pneumonitis with intraalveolar hemorrhage. In the spleen there was marked germinal center formation containing reactive B-cells. Lesions of the kidneys resembled those found in cadmium poisoning in man, primarily a proliferative glomerulonephritis.

Animals↗
PubMed1979

Distribution, frequency, and quantitative analysis of estrogen, progesterone, androgen, and glucocorticoid receptors in human breast cancer.

The distribution and frequency of steroid hormone receptors are described 329 patients with breast cancer. The distribution of each of the steroid hormone receptors is unimodal with a progressive increase in the proportion of patients positive at lower receptor values. Receptor values expressed as fmol/mg cytoplasmic protein are well correlated with values expressed as fmol/mg breast tumor. Estrogen receptor was positive in 53% of the patients; progesterone receptor was positive in 38% of the patients; glucocorticoid receptor was positive in 52% of the patients; and androgen receptor was positive in 31% of the patients. The type of tissue assayed did not affect steroid hormone receptor positivity. For primary tumors, there was no correlation between steroid hormone receptor positivity and location of the tumor in the breast, size of the tumor, or extent of the disease. Each of the steroid hormone receptors was positively associated with each of the other steroid hormone receptors. Estrogen receptor was correlated with menopausal status and axillary nodal status, but these correlations did not exist for the other steroid hormone receptors. Estrogen receptor was not correlated with age after adjustment for menopausal status. The other steroid hormone receptors were not correlated with age.

Adult↗