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Biomedical subjects

J H Becker

Publications and source records attributed to J H Becker.

15 recordsLinked to original sources
PubMed1992

Curriculum at the Scholl College. Toward mainstream medical education.

The Dr. William M. Scholl College of Podiatric Medicine in Chicago recently affiliated with a teaching hospital, the Illinois Masonic Medical Center, and used this alliance as a catalyst to effect a change in the clinical curriculum. The affiliation set up a joint venture to operate two clinics, one on Scholl College's traditional campus and one at the teaching hospital. At the hospital site, Scholl College students rotate through clinical externships in areas such as internal medicine, emergency medicine, and podiatric elective; podiatric and general medical residents assist in the tutelage of the students. At the Scholl College campus, beginning clinical students learn basic skills in a teaching clinic, then refine and further their skills in a comprehensive clinic under the guidance of faculty members. The faculty and administration at Scholl College have embraced the concept of mainstream medical education, and are striving to prepare podiatric physicians to practice 21st century medicine.

Chicago↗
PubMed1986

Juvenile gastrointestinal polyposis or the infantile Cronkhite-Canada syndrome.

This is a report of a case of juvenile gastrointestinal polyposis consisting of widespread juvenile polyps encountered from the stomach into the rectum. Only few cases have been reported, and extra intestinal manifestations include clubbing of fingers, macrocephaly, hypotonia, hepatosplenomegaly, anemia, and protein-losing enteropathy. The outcome is usually dismal, the children barely becoming older than 2 years. Modern fibreoptic endoscopy with polypectomies performed via the upper and lower gastrointestinal intestinal tracts and via a midbowel ileostomy may offer a viable form of management.

Humans↗
PubMed1986

Inhibition of Na+ flux in Chinese hamster ovary cells and Swiss 3T3 cells by a potent new derivative of amiloride, methylisopropyl-amiloride.

Amiloride inhibits the mitogen-stimulated Na+ influx of cultured fibroblasts with very low affinity. We have therefore analyzed eight new derivatives of amiloride for their efficacies of inhibiting the Na+ flux in Chinese hamster ovary cells (CHO-K1). Four of these analogs demonstrate markedly enhanced potencies relative to amiloride. One of the derivatives, methylisopropyl-amiloride (MIA), is approximately 900-fold more potent (ID50 = 42 nM) than amiloride in inhibiting Na+ uptake of these cells. Inasmuch as external Na+ ions antagonize amiloride inhibition of Na+ influx competitively, we investigated the ability of MIA to inhibit Na+ flux in the absence of external Na+ ions. The ID50 value determined for MIA inhibition of CHO-K1 cell Na+ efflux from Na+-loaded cells into Na+-free media is 15 nM. We also examined the efficacy of MIA for Na+ efflux inhibition in a nontransformed fibroblast cell line, Swiss 3T3. The ID50 value for inhibition of Na+ efflux from 3T3 cells is comparable to that for CHO-K1 cells. Thus, we have identified a highly potent derivative of amiloride, MIA, that inhibits Na+ flux at nanomolar concentrations in both a transformed and a nontransformed cell line. It is possible that MIA may serve as a useful tool for biochemical characterization of the mitogen-stimulated Na+ transporter and for assessment of the role of this transporter in mitogenesis.

Amiloride↗
PubMed1985

Localization of parathyroid adenomas by digital subtraction angiography. A report of 4 cases.

Intravenous digital subtraction angiography provides an accurate but not specific method for localization of small vascular tumours. It is carried out on outpatients as an intravenous procedure and takes only 40 minutes. It appears to be eminently suited to the demonstration of parathyroid adenomas and shows that a hyperplastic parathyroid gland can produce a significant enough vascular blush to create a visible image.

Adenoma↗
PubMed1979

Properties of Na-K pump in primary cultures of kidney cells.

Activities related to Na-K transport were measured in cell cultures of ground squirrel kidney cortex in order to compare these cells with those of intact kidney and of continuous cell lines. A microsomal preparation containing plasma membrane Na,K-ATPase from fresh kidney showed twice the activity of a similar preparation from 72-hour cultured cells. Na,K-ATPase of homogenates of 72-hour cells showed one-third to one-fourth the specific activity of that from 6-hour cultured cells. The associated K-dependent phosphatase activity also declined as a function of time in culture. The ouabain-sensitive influx of K into 6-hour cultured cells was twice as great as the K influx into 72-hour cells. The number of sites binding 3H-ouabain in intact cultured cells declined 81% on a cell protein basis between 6 and 72 hours in culture. This decline in ouabain binding sites was relatively greater than that of K influx, so that the K turnover number increased over this same time period. The decline in ouabain-sensitive K influx during culture was complementary to an increase in furosemide-sensitive K influx. Measurements of unidirectional and net K fluxes showed that there were three components of K influx into 3-day cultured cells: ouabain-sensitive Na:K exchange, furosemide-sensitive K:K exchange, and K diffusion. In the 6-hour cultures, however, there was no furosemide-sensitive K:K exchange. Thus, after three days in culture ground squirrel kidney cells lose a feature characteristic of the original parent cells (high Na,K-ATPase activity), and gain a feature common to many undifferentiated cultured cells (furosemide-sensitive K:K exchange).

4-Nitrophenylphosphatase↗
PubMed1978

Na-K pump and Na-K-ATPase: disparity of their temperature sensitivity.

As previously observed in red blood cells, ouabain-sensitive K influx of kidney cells grown in culture for 3 days was much less inhibited by cooling that Na-K-ATPase of the same cells. (At 5 degrees C K influx was 9.7% of that at 38 degrees C, Na-K-ATPase, 1--2%.) Resealed ghosts of erythrocytes of ground squirrels were made containing 24Na and ATP, and the Na efflux and ATP hydrolysis were measured simultaneously. Under these conditions there was no difference in the reduction of activity with cooling, and the amount of reduction was close to that of active K transport in intact cells. The high sensitivity to temperature, characteristic of broken membranes, could not be induced in intact cells or resealed ghosts by eliminating either the Na/K gradient or the ATP gradient nor by chelation of cellular and extracellular Ca. It could not be eliminated in broken membranes by protection with ATP or Mg. Structural reorganization of membrane during lysis may cause the increase in temperature sensitivity of Na-K-ATPase.

Adenosine Triphosphate↗