Search PubMed⌕ Search

Biomedical subjects

D Frank

Publications and source records attributed to D Frank.

At least 109 records · Page 6Linked to original sources
PubMed1984

A unique ATP-dependent DNA topoisomerase from trypanosomatids.

Crithidia fasciculata DNA topoisomerase (22) has been purified to near homogeneity from trypanosomatid cell extracts. The purified enzyme catalyzes the reversible interconversion of monomeric duplex DNA circles and catenanes in an ATP dependent reaction. Reversible catenane formation is affected by the ionic strength and is dependent upon the action of a crithidial DNA binding protein, which could be substituted for the polyamine spermidine. Covalently sealed DNA circles are specifically used as substrates for decatenation. Nicking, but not relaxation per se, inhibits network decatenation and has little or no effect on catenane formation. The catalytic properties of this enzyme and its potential role in the prereplication release and post replication reattachment of kDNA minicircles are discussed.

Adenosine Triphosphate↗
PubMed1984

Intestinal perforation associated with cytomegalovirus infection in patients with acquired immune deficiency syndrome.

Gastrointestinal complications are an important aspect of the acquired immune deficiency syndrome. In this report we describe two male homosexuals with the acquired immune deficiency syndrome whose gastrointestinal symptoms culminated in the complication of intestinal perforation. Cytomegalovirus inclusions are seen prominently in the areas of perforation. The pathogenic role of cytomegalovirus in these cases is discussed. We propose that cytomegalovirus-induced enteritis may lead to bowel perforation in patients with the acquired immune deficiency syndrome.

Acquired Immunodeficiency Syndrome↗
PubMed1984

The effects of teaching clinical clerks psychotherapy skills in the outpatient department.

We have described a psychiatric clerkship which is highlighted by a clinical exposure for the students to the practice of psychodynamic psychotherapy on relatively well-functioning outpatients. Students assigned this rotation are shown to opt for psychiatry significantly more often and rate the educational experience as significantly more positive when compared to psychiatry clerks other teaching hospitals which do not emphasize this clinical experience in outpatient psychotherapy. In addition, students undergoing this type of clerkship are shown to significantly improve in their ability to the histories and interact with medically ill patients, suggesting a further beneficial effect of the experience in conducting psychotherapy during the clerkship.

Ambulatory Care Facilities↗
PubMed1983

Dopamine-inhibited release of prolactin and intermediate lobe-POMC-peptides: different modulation by opioids.

Primary monolayer cultures of anterior or intermediate lobe (IL) cells from rat pituitaries were grown in microtiter plates, and the test substances were added after 5 days. The hormones were measured by RIAs for rat prolactin, -MSH, ACTH and beta-endorphin/beta-LPH. The dopamine (DA) inhibition of prolactin secretion was attenuated by addition of equimolar (10(-7), 10(-6)M) concentration of beta-endorphin. Furthermore, the DA effect was blocked, when the beta-endorphin-release of anterior pituitary cells was stimulated by vasopressin. In contrast, the DA induced inhibition of hormone-release of IL-cells (e.g. -MSH, ACTH and beta-endorphin) was not influenced by addition of opioids. Our results indicate, that under certain conditions (e.g. stress) the stimulated secretion of prolactin could be mediated partially by a direct action of pituitary beta-endorphin at the lactotroph. On the other hand, we found no indication for a modulation of the dopamine-induced inhibition of IL-peptides by opioids.

Adrenocorticotropic Hormone↗
PubMed1981

Urethral pressure profilometry: a low compliant recording system with perfused catheter.

A new catheter for recording the urethral closure pressure profile (UCPP) in men and women in introduced. The measuring system utilizes perfusion and saline as a transmission medium. The dynamic response of the whole catheter system as a unit was studied in vitro, and profile studies of the female urethra were performed in vivo using a solid catheter equipped with micro-transducers as a reference. The small transmission volume and low-compliant perfusion gave a sufficient bandwidth for recordings of the UCPP. No significant difference was found in closing pressure and functional length in the UCPP of women between the new catheter and the solid catheter.

Animals↗
PubMed1981

Growth characteristics af low Na+ concentration and the stability of the Na+ requirement of a marine bacterium.

Studies of the marine bacterium Alteromonas haloplanktis 214 (formerly referred to as marine pseudomonad B-16) showed that as the Na+ concentration in the growth medium decreased from 230 to 34 mM, the lowest concentration permitting growth, the length of the lag period preceding exponential growth increased. Once growth had begun, except for a slight reduction in rate of growth at 34 mM Na+, the generation time and extent of growth remained essentially constant over the range of Na+ concentrations tested. Plate counts showed that during the lag period the numbers of viable cells introduced as inoculum into a complex medium containing 33 mM Na+ decreased exponentially before increasing. Repeated subculture of the cells at 33 mM Na+ failed to eliminate the lag period or reduce the loss of viability of the cells. The viability loss and the lag period could be eliminated either by raising the NaCl concentration to 130 mM or by adding sufficient sucrose to make the osmotic pressure of the medium equal to that obtained by adding 130 mM NaCl. In a chemically defined medium, sucrose added to maintain tonicity reduced but did not eliminate the lag periods obtained at suboptimal Na+ concentrations. Increasing the number of cells plated on trypticase agar medium reduced the Na+ concentration required to permit growth. Evidence was obtained of a requirement of A. haloplanktis for Ca2+ for growth. Ca2+ spared to a small extent the requirement for Na+ for growth. Some 10(10) cells of a histidine-requiring, streptomycin-resistant mutant of A. haloplanktis 214, still viable after treatment with N-methyl-N'-nitro-N-nitrosoguanidine, were screened for capacity to grow in the absence of Na+. Since no non-Na+-requiring mutants were isolated, the requirement of this organism for Na+ would appear to be extremely stable.

Calcium↗
PubMed1981

The depressed response of spleen cells from rats infected by Trypanosoma lewisi in producing a secondary response in vitro to sheep erythrocytes and the ability of soluble products of the trypanosome to induce this depression.

The non-pathogenic Trypanosoma lewisi depresses the ability of infected rat spleen cells to respond immunologically to sheep erythrocytes. A study was made to determine whether the parasite would produce this same phenomenon in vitro in Marbrook culture vessels with erythrocyte-primed spleen cells from normal rats; the antibody response of the spleen cells was measured by the plaque-forming cell assay. Soluble factors from 1 X 10(7) T. lewisi depress the ability of primed cells to form a secondary antibody response in vitro to sheep red cells. The intensity of the inhibitory activity depends on the stage of the life cycle of the parasite and can also be demonstrated using sonicated, frozen-thawed or boiled preparations of the organism. It is suggested that the immunodepressive substances may be a glycoprotein and that it (they) may arise both from the intracellular and from the extracellular compartments of the organism. It is likely that the host-parasite associations in trypanosomiasis are regulated by such soluble parasite factors.

Animals↗
PubMed1978

Psychiatric aspects of geriatric crisis intervention.

Data on 64 geriatric patients treated by the Psychiatric Crisis Team at the Jewish General Hospital were reviewed. A control group of non-geriatric patients was selected at random for comparison. The average age of the geriatric group was 69.4 years compared to 33 in the control group. Women predominated in the geriatric group. Precipitating factors were more easily delineated in the geriatric group. Physical illness, loss of a close relative and relocation were the most common precipitating events in the geriatric group. Depression, psychotic and neurotic, was the predominant diagnosis in the older group and schizophrenic psychosis in the control group. Compared to the control group, the geriatric patients were discharged sooner and were more easily managed. Only two geriatric patients required institutionalization. The study supports the value of prompt and comprehensive geriatric crisis intervention.

Aged↗