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Biomedical subjects

W N Scott

Publications and source records attributed to W N Scott.

At least 91 records · Page 5Linked to original sources
PubMed1981

Effects of insulin on ribonucleic acid synthesis in toad urinary bladder.

We previously found that the sustained rise in active sodium transport by the toad urinary bladder after exposure to insulin is associated with the synthesis of a membrane protein with a molecular weight of 25,000. Studying the effects of insulin on the incorporation of uridine into RNA of epithelial cells of the bladder, we now report that insulin causes a 39% increase in the incorporation of [3H]uridine into poly(A)-containing RNA extracted from granular cells, the predominant epithelial cell type. The increased accumulation of label in RNA, most notably species ranging from 5-10S, could be demonstrated whether cells were pulsed with [3H]uridine or continuously exposed to the label. Using a reticulocyte lysate system, we compared the translation products of RNA from untreated and insulin-treated granular mucosal cells. Exposure to insulin was associated with the expression of a mRNA coding for a protein with molecular weight of approximately 25,000, similar in size to the insulin-induced membrane protein we previously identified in the intact tissue.

Animals↗
PubMed1980

Transporting renal epithelium: culture in hormonally defined serum-free medium.

A hormonally defined medium was used to isolate a homogeneous epithelioid cell population from canine kidney. Monolayers of these cells form domes, an indication of active ion transport, and this process is inhibited by ouabain. This technique allows the isolation of primary cultures of renal epithelial cells, free of fibroblasts, for the characterization of biochemical and physiological properties related to renal function.

Animals↗
PubMed1979

Inhibition of fatty acid synthesis prevents the incorporation of aldosterone-induced proteins into membranes.

2-Methyl-2-[p-(1,2,3,4-tetrahydro-1-naphthyl)phenoxy]propionic acid (TPIA), an acetyl coenzyme A carboxylase inhibitor, blocks the aldosterone-induced increase in transepithelial sodium transport. To examine the requirement for ongoing fatty acid synthesis and/or elongation in the aldosterone-induced alteration of cellular protein metabolism in the toad's urinary bladder, the effect of TPIA has been examined in double-labeled amino acid incorporation experiments. TPIA itself has no effect on the pattern of protein labeling in either the "soluble" or a plasma membrane-enriched fraction. However, inhibition of fatty acid synthesis selectively inhibits the aldosterone-induced incorporation of membrane proteins without altering the labeling of soluble cell protein. These results indicate that ongoing fatty acid synthesis is required for the hormone-induced changes in plasma membrane protein metabolism.

Aldosterone↗
PubMed1979

Toad carbonic anhydrase: purification of the enzyme from erythrocytes of Bufo marinus and comparison with the enzyme activity in the urinary bladder.

1. Two forms of carbonic anhydrase, having isoelectric points of 6.1 and 5.8, were purified from erythrocytes of the toad, Bufo marinus, and the presence of a third form, pI = 5.4, was demonstrated. 2. Each of the two purified isozymes catalyzed the hydration of CO2 and the hydrolysis of nitrophenyl acetate esters at rates characteristic of Type C (or high-activity) forms of carbonic anhydrase. 3. Both forms of the erythrocyte enzyme have similar molecular weights (approx 29,000), amino acid composition, sensitivity to acetazolamide, and kinetic properties. 4. The epithelium of the toad's urinary bladder also was found to contain significant amounts of carbonic anhydrase, which appears by isoelectric focusing to be indistinguishable from the enzyme isolated from the erythrocyte.

Amino Acids↗
PubMed1979

The total condylar knee prosthesis. A report of two hundred and twenty cases.

The total condylar knee prosthesis is a non-hinged surface replacement which can be used for almost all knee deformities. This report discusses the first consecutive 220 arthroplasties in 183 patients. Follow-up time was three to five years. Before operation eighty-six knees had more than 10 degrees of fixed varus deformity and thirty-one knees had more than 10 degrees of fixed valgus deformity. All patients were assessed using The Hospital for Special Surgery scoring system. Of the total of 220 knees, 137 (62%) were rated excellent; sixty-one (28%), good; ten (4.5%), fair; and twelve (5.5%), poor. Of 139 osteoarthritic knees, 93% were rated excellent or good. Complications included three deep infections and four cases of posterior subluxation. The over-all reoperation rate was 3.6%.

Arthritis, Rheumatoid↗
PubMed1979

Surgical treatment of reruptures of the tendoachilles following nonsurgical treatment.

Nine patients who sustained a rerupture of their Achilles tendon after nonsurgical treatment were evaluated both subjectively and objectively with the Cybex isokinetic dynamometer. Subjectively, only 5 of the 8 patients were satisfied as compared to a 93% satisfaction rate in our previous series of patients with primary surgical repair. Cybex measurements were statistically inconsistent, unlike the primary repairs. This small series of patients in which the tendoachilles was reconstructed following failed nonsurgical treatment suggests that early surgical repair is the treatment of choice unless otherwise medically contraindicated.

Adult↗
PubMed1978

Comparison of toad bladder aldosterone-induced proteins and proteins synthesized in vitro using aldosterone-induced messenger RNA as template.

Using double-labeled isotope techniques, it can be shown that aldosterone induces the synthesis of several proteins in the mitochondria-rich (MR) cells of the toad's urinary bladder. Induced proteins have been identified both in the plasma membrane (mol wt = 170,000, 85,000 and 12,000) and the cytosol (mol wt = 36,000, 12,000 and 6,000) fractions of these mucosal cells. We have also shown that aldosterone (Aldo) induces the synthesis of a class of RNA having the properties of messenger RNA (mRNA). mRNA isolated from Aldo-treated mucosal cells was used as template in a cell-free protein-synthesis system prepared from rabbit reticulocytes. Preparations charged with mRNA from Aldo-treated cells synthesized two proteins that were not labeled when mRNA from control tissues was used as template. The electrophoretic mobility of one of these proteins was similar to an Aldo-induced membrane protein (mol wt = 70,000) found in the intact tissue.

Aldosterone↗
PubMed1978

Effects of ascorbate and ATP upon amino acid transport in the toad's cornea.

We have examined the effects of ascorbate upon amino acid uptake by the in vitro toad cornea. Physiologic levels of ascorbate increase the uptake of leucine by approximately 35% but have no effect upon the uptake of alanine. Uncouplers of oxidative phosphorylation do not inhibit the stimulation by ascorbic acid of leucine accumulation, indicating the increased synthesis of ATP is not the mechanism; exogenous ATP, unlike ascorbate, stimulates the uptake of both alanine and leucine. Carbon monoxide blocks the effects of ascorbate, whereas 2-heptyl-4-hydroxyquinoline-N-oxide (HOQNO), which inhibits "reverse" electron transfer, enhances the accumulation of leucine. The evidence suggests that ascorbate serves as an energy source for the uptake of leucine.

4-Hydroxyaminoquinoline-1-oxide↗
PubMed1978

Supracondylar osteotomy in thalassemia.

The skeletal system manifestations of thalassemia are characterized by severe osteoporosis, frequent fractures and delayed healing. Permanent deformity and disability can complicate the fractures. Surgical correction of deformity by osteotomy of severely osteoporotic bone and immobilization without internal fixation was successful in a 20-year-old woman. While operative correction of deformity is not routinely recommended, the good experience with this case suggests that similar orthopedic procedures can be included in the treatment of thalassemia.

Adult↗
PubMed1978

Humane considerations in the use of experimental animals.

Various considerations aimed at improving the welfare of experimental animals are discussed, with particular reference to the situation in the United Kingdom. These include, inter alia, codes of standards for accommodation and equipment, prevention or reduction to a minimum of pain, and the appointment of committees consisting of biological scientists, veterinarians, teachers and lay persons to advise on proposed experiments.

Animals↗
PubMed1976

Total condylar knee replacment: preliminary report.

The Total Condylar Prosthesis is a non-hinged unit designed to: replace the patellofemoral articulation; improve fixation of the tibial component by means of a stout central peg; permit accurate and reproducible insertion. The cruciate ligaments are excised to obtain better tibial fixation. Instability has not been a problem except in a few cases of a technical error (removal of excessive bone from the tibia creates instability in flexion). The prosthesis cannot be positioned by "eye" and the instrumentation must be applied exactly.

Humans↗
PubMed1976

Ruptures of the tendo achillis. An objective assessment of surgical and non-surgical treatment.

A comparative study is presented of seventy-nine patients with rupture of the tendo achillis, forty-eight of whom were treated surgically and thirty-one, non-surgically. With one exception, all were healthy, athletic individuals. Twenty-two per cent of the patients had an initial misdiagnosis. The patients treated surgically were more satisfied with the results of their treatment. Strength, power, and endurance as measured on the Cybex II dynamometer revealed that the patients treated non-surgically attained only 72 per cent of normal strength and 70 per cent of normal power and endurance as compared with the surgically treated patients. Wound complications occurred in only two patients and no reruptures occurred in the surgically treated group, whereas there were nine rereptures in the group not treated surgically.

Achilles Tendon↗