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Biomedical subjects

J Greenberg

Publications and source records attributed to J Greenberg.

At least 217 records · Page 12Linked to original sources
PubMed1977

The identification of the F-cell in the dog pancreas as the pancreatic polypeptide producing cell.

The endocrine cells of the processus uncinatus in the dog pancreas were investigated with special reference to the formerly known F-cell. The F-cell was detected frequently in the periphery of pancreatic islets as well as among exocrine tissue. In both localizations the F-cell shows similar ultrastructural features. Membrane-bound irregularly shaped secretory granules of variable electron density were seen. The cell possesses all features of an endocrine polypeptide secreting cell. Using the immunofluorescence and immunoperoxidase technique in the uncinate processus of the dog, we could reveal that the anti-sera against bovine pancreatic polypeptide (BPP) reacts with the cell which is localized at the same sites as the F-cell. We therefore conclude that the pancreatic F-cell is identical to the pancreatic polypeptide-producing cell. The other endocrine cell types of the dog pancreas are glucagon-producing A-cells, insulin-producing B-cells, and somatostatin-producing D-cells, as well as serotonin-producing EC-cells which are regularly present in the dog pancreatic islets and also scattered among exocrine tissue and the duct epithelial cells.

Animals↗
PubMed1977

Topically applied antifungal agents. Percutaneous penetration and prophylactic activity against trichophyton mentagrophytes infection.

Penetration and prophylactic activity against Trichophyton mentagrophytes infection of topically applied antifungal agents were studied in human volunteers. The concentration and persistence of drug in the stratum corneum was determined after different treatment schedules and from different vehicles. Measurable levels of griseofulvin, clotrimazole, miconazole nitrate, and thiabendazole remained in the skin four days after discontinuation of topical applications. Griseofulvin, miconazole, and clotrimazole exhibited prophylactic activity against infection by T mentagrophytes spores in a standardized test. Griseofulvin was a significantly better prophylactic agent than either miconazole or clotrimazole.

Administration, Topical↗
PubMed1977

Obesity obscuring breast cancer: a case report.

There is normally a layer of fat in the breast between the parenchyma of the breast and the skin. This is frequently thin and does not preclude the palpation of a tumor mass which involves the breast parenchyma. In patients suffering from obesity this fat pad becomes much thicker and obscures any underlying masses arising from the breast parenchyma. A case is reported in which a woman who was markedly obese lost a significant amount of weight and presented a bulge which was found to be carcinoma. This situation, in which fat obscures underlying breast lesion, has been observed in a number of patients. Attention is called to the limited value of physical examination of the breast in markedly obese patients. If any suspicion exists or if the patient is a candidate for cancer from a familial standpoint, mammograms are indicated.

Breast Neoplasms↗
PubMed1977

Host modification and restriction with a mycobacteriophage isolated from a pseudolysogenic Mycobacterium chelonei.

A pseudolysogenic Mycobacterium chelonei and its phage phi630 are described. Phage phi630 is the first mycobacteriophate reported to be resistant to the nonpolar solvents chloroform, dioxan and diethyl ether. The phage had a latent period of 75 min, a rise period of 90 min and a burst size of 5I. Evidence is presented for host modification and restriction. Phage phi630A, grown on host strain M. chelonei F-630 Rg, plated on the alternative host M. smegmatis ATCC607 with an efficiency of plating (e.o.p.) of 10(-5). Phage phi630B, grown on host M. smegmatis, plated with an e.o.p. of 10(-5) on the alternative host F-630 Rg. Phages phi630A and phi630B absorbed equally well on their alternative hosts and on their indicator host strains. The progeny of plaques from initial platings on the alternative host, when grown in the alternative host, exhibited a marked reduction in e.o.p. on their original host.

Bacteriophage Typing↗
PubMed1977

Effect of ethambutol on the viable cell count in Mycobacterium smegmatis.

Soon after a strain of Mycobacterium smegmatis was exposed to ethambutol (EMB), the number of viable cells increased dramatically above the number in a drug-free control. This rapid rise did not occur when the culture was maintained at 4 degrees C instead of 37 degrees C, when an EMB-resistant mutant was used, when auxotrophs were exposed in medium lacking nutrients essential for growth, nor when the levo form of EMB was used. EMB caused no increase in deoxyribonucleic acid synthesis, nor in septum formation of dividing cells. Treated cells changed morphologically, resulting in a lower surface area-to-volume ratio. Whereas EMB did not eliminate cell clusters, the cluster size decreased markedly as detected by filtration and Coulter counter measurements. We concluded that EMB causes a reduced surface-to-volume ratio, leading to reduced cell cohesion and a consequent reduction in cluster size, reflected in an increase in colony-forming units.

Cell Count↗
PubMed1977

Generation of miniplasmids from copy number mutants of the R plasmid NR1.

Small, closed circular deoxyribonucleic acid molecules, called miniplasmids, were observed in Escherichia coli harboring copy number mutants of the R plasmid NR1 after growth in medium containing tetracycline. The level of tetracycline resistance conferred by the copy mutant plasmids was lower (3 to 6 microgram/ml) than that conferred by NR1 (100 MICROGRAM/ML). The presence of the miniplasmid enhanced the level of tetracycline resistance conferred by the copy mutant. Miniplasmids of molecular weights 4 X 10(6) to 13 X 10(6) were found. They carried no antibiotic resistance markers and could be eliminated by growth in the presence of chloramphenicol and/or streptomycin-spectinomycin. Studies with the restriction endonucleases EcoRI and Sal I indicated that the miniplasmids are derived from the region of the copy mutant plasmids that contains the origin for replication of the resistance transfer factor. There were approximately 12 copies of the miniplasmid per chromosome, compared with 3 and 6 copies of the copy mutants of NR1. The miniplasmids appeared to be incompatible with the copy mutant plasmids.

Chloramphenicol↗
PubMed1977

Temporal correlation of lymphocyte blastogenesis, skin test responses and erythema during dermatophyte infections.

The development of cellular hypersensitivity, as measured by lymphocyte blastogenic and skin tests assays, was correlated with intensification of lesion erythema in guinea-pigs infected with Trichophyton mentagrophytes. Development of lymphocyte blastogenic responses to trichophytin was assayed using forty infected animals and twenty controls; blastogenic conversion occurred between 9-11 days post spore application. The onset of cellular hypersensitivity was assayed in vivo in twenty infected guinea-pigs by skin testing at intervals after infection; positive responses occurred between 9-11 days post spore application which coincided with the time of blastogenic conversion. Clinical characteristics of lesions were followed in a group of twenty-four animals: lesions first appeared on day 7; erythema intensified until day 10; lesions reached maximum size by day 13; and alopecia began on day 17. Since cellular hypersensitivity (positive skin test and lymphocyte blastogenesis) develops at the same time as lesions reach maximum erythema, cellular hypersensitivity appears to be responsible for the intense inflammatory response associated with ringworm infections.

Animals↗
PubMed1977

Undergraduate medical education in geriatrics: nursing home experience.

Preclinical medical students undertook an elective course in geriatrics which combined instruction in history taking, physical diagnosis, and problem-oriented assessment of elderly patients in a nursing home. A drug utilization review and specific drug therapy plans were formulated by pharmacy students. The project identified general problems susceptible to institutional as well as individual remedy. The students were led beyond their initial preoccupation with "physical complaints" to interest in pertinent psychological, social, and economic factors. A model of geriatric education for health science students can productively link the health science center and community nursing homes with benefits for the student, the patient, and the nursing home.

Aged↗
PubMed1976

Seasonal changes in the fine structure of the accessory sex gland in the mole (Talpa europaea).

The mole has a single pair of accessory sex organs with features of both the prostate and the seminal vesicle, for which the term prostate gland is not appropriate. Seasonal changes occuring in this gland were related to four periods: a) the quiescence period, b) the maturation period, c) the active period and d) the involution period. During the quiescence period the cuboidal epithelial cells display a quasi-embryonic fine structure and are sparse in cytoplasmic organelles, but rich in glycogen and lipopigment. With the onset of sexual activity glycogen and lipopigment disappear and the rough endoplasmic reticulum as well as the Golgi apparatus begin to proliferate. The fully active gland is lined by a low epithelium with parallel stacks of rough endoplasmic reticulum, a large Golgi apparatus and several lysosomes and secretory granules. In the involution period the gland collapses and the epithelial cells are eliminated by hetero- and autophagic processes. During this period a great number of presumably endocrine cells were observed. The results were compared with findings in experimental studies and those on postnatal development of accessory sex glands in laboratory animals.

Animals↗
PubMed1976

Block of electrically induced contractions of guinea pig longitudinal muscle by prostaglandin synthetase and receptor inhibitors.

Inhibitors of prostaglandin synthetase as well as prostaglandin receptor inhibitors block electrically induced contractions of the longitudinal muscle of the guinea pig ileum. This blockade is selectivety reversed by some prostaglandins, particularly those of the E series. There is a very close parallel between the potency with which the synthetase inhabitors block transmission and inhibit the enzyme. That blockade is actually accompanied by inhibition of synthesis of PG was shown by inhibition of arachidonic acid contractions of the tissue by indomethacin. The inhibition of transmission by indomethacin involves block of acetylcholine release as shown by direct assay and by the fact that physostigmine can reverse the block. Physostigmine also reverses block of transmission by prostaglandin receptor inhibitors and by morphine but not that produced by chlorpromazine or papaverine. Other evidence for a presynaptic site of action for the synthetase and PG receptor inhibitors is indicated by lack of effect of blocking concentrations on response of the tissue to exogenous acetylcholine. That prostaglandin reverses block of transmission by a presynaptic effect was shown by lack of reversal of atropine and papaverine inhibition of electrically induced contractions; both of these drugs produce this effect directly on the smooth muscle. These results are compatible with the previous postulate that a prostaglandin system, comprised of prostaglandin, its synthesizing enzyme and its receptor, is directly involved with the release of acetylcholine in the ileum.

Acetylcholine↗
PubMed1976

Serum antithrombin in coronary-artery disease.

Serum antithrombin activity (AA) was correlated with coronary angiographic findings in 69 patients with documented angina. There was excellent correlation between normal values and normal coronary circulation or only one-vessel stenosis in 30 of 35 patients (86%). When AA was above 90%, 90% of patients (20 of 22) had normal circulation or one-vessel occlusion. In 24 patients AA values were significantly decreased. Coronary angiography in this group revealed three with normal circulation or only one-vessel involvement (10%); 21 of 24 had two or three vessels occluded (90%). The correlation between severe CAD and low AA is probably coincidental to a "triggered" or "turned-on" clotting system. The most practical clinical contribution of AA estimation relates to this capacity to identify angina patients in whom clot-preventive measures (aspirin; dipyridamole; anticoagulants) might prove beneficial.

Adolescent↗
PubMed1976

Antithrombin and heparin antithrombin patterns in pre-thrombosis and thrombosis.

An antithrombin assay (AA) and an antithrombin assay modified by the addition of heparin (H-AA) were performed using sera from healthy subjects, patients predisposed to thrombosis, and patients with thromboembolic disease. Characteristic AA, and H-AA patterns were found in each group. Normal controls and four of 39 "pill" patients (10%) had normal AA and H-AA findings (Pattern A). Normal AA, with "decreasing" H-AA (Pattern B) was found in sera of 31 of 39 "pill" patients (80%) and three patients who had non-embolic arterial occlusive disease. Low AA and "decreasing" H-AA (Pattern C) occurred in sera of four "pill"-takers (10%) and one patient who had an arterial embolus. Low AA and low H-AA (Pattern D) developed in sera of eight patients with thrombophlebitis and seven patients with pulmonary embolus. It is concluded that the AA and H-AA assays help to identify thrombosis-prone (Pattern C) and thrombotic (Pattern D) individuals for whom antiplatelet (aspirin; dipyridamole) or anticoagulant therapy might be beneficial.

Antithrombins↗