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Biomedical subjects

H Silverman

Publications and source records attributed to H Silverman.

At least 55 records · Page 3Linked to original sources

A multicenter retrospective review of the mandibular staple bone plate.

The mandibular staple bone plate, herein referred to as the staple, has been used as a reconstructive device to improve mandibular function for more than a decade. This report presents the clinical and radiographic findings of a retrospective survey of 160 patients from three separate practices over an eight-year period (1975-1983). The criteria established at the 1978 NIH-Harvard Consensus Development Conference on Dental Implants were used to evaluate results. The study also evaluates experiences with other procedures used in conjunction with the staple.

Bone Plates↗

Breeding and offspring rearing ability of C57BL/6J dystrophic mice.

The antiepileptic drug phenytoin, administered in drinking water for 104 days, was used to reduce the neural overactivity (pseudomyotonia) of C57BL/6J dystrophic (dy2J/dy2J) male mice in an attempt to improve their breeding success over a 90-day period. Male dy2J/dy2J mice have difficulty in successfully mounting females due to the pseudomyotonia affecting their hindlimb musculature. Breeding success, as judged by litter frequency, of dy2J/dy2J males receiving phenytoin (5 micrograms/ml serum) was compared with untreated dy2J/dy2J and phenotypically normal (+/?) male and female mice. Phenytoin did not enhance male dy2J/dy2J breeding success. Based on dy2J/dy2J crosses with +/? animals, the dy2J/dy2J female was a more successful breeder than the dy2J/dy2J male. In terms of litter frequency, litter size, and offspring birth weight, dy2J/dy2J females (age 8-21 wks.) bred as efficiently as +/? females of the same age. Dystrophic females were deficient in offspring rearing capabilities as evidenced by lower offspring survival rates and weaning weights.

Animals↗

Increase of muscle mitochondrial content with age in murine muscular dystrophy.

Comparison of morphological features of gastrocnemius muscle fibers in normal and dystrophic (dy2J) mice during development was undertaken to determine the time course of increased oxidative capacity in dystrophic fibers. Measurements of mitochondrial volume percent and of Z-line width were made in superficial fast-twitch fibers using electron microscopy and stereological techniques. Dystrophic fibers develop a progressively higher mitochondrial volume percent than normal fibers after 1 month of age. Z-line width is positively correlated with mitochondrial volume percent. The results support the hypothesis that progressive changes in muscle fiber properties result from abnormal neural activity (pseudomyotonia) in dystrophic animals.

Aging↗

Effect of hormonal deprivation on the bladder defense mechanism.

The mucopolysaccharide (MPS) layer of the bladder has been implicated as a bacterial anti-adherence factor in previous experimentation. Production of MPS is known to be related to hormones in other systems of the body and probably to the urinary system. Due to the known rising incidence of urinary tract infection in most menopausal females, an experimental model using oophorectomized rabbits was designed. Oophorectomized and control rabbits were observed for their ability to clear their bladder of experimentally induced Escherichia coli 04 infections. There was a 2-fold increase in the mean number of days for clearance of bacteria among oophorectomized rabbits versus control rabbits. Twice as many rabbits cleared their infection within 1 week in the control population versus the oophorectomized population. To further examine the relationship of oophorectomy to urinary tract infection, a group of 1030 female canines in an animal veterinary practice was studied. It was found that the incidence of infection was higher in the spayed population than in the non-spayed group. The non-spayed group seem to have an age dependent history of urinary infection whereas ovariohysterectomy appeared to abolish this relationship to age.

Age Factors↗

Leiomyosarcomas of the small intestine.

Small bowel leiomyosarcomas are uncommon but potentially curable tumors often diagnosed at an advanced stage. Twenty such lesions were studied, and 19 of these produced symptoms and signs. Clinical findings included abdominal pain in 17 (85%), rectal bleeding in 8 (40%), anemia in 7 (35%), intraperitoneal perforation in 6 (30%), and abdominal mass in 4 (20%). Various abdominal x-ray examinations revealed nonspecific abnormalities (ileus, bowel obstruction, abdominal mass) in about half the cases in which they were obtained, but in only one instance was the correct diagnosis of small bowel tumor made preoperatively. Five of 12 patients undergoing resection in hope of cure survived five years. These tumors tend to metastasize by hematogenous dissemination, peritoneal implantation, local invasion, and, uncommonly, lymphogenous spread. Wide small bowel resection with adjacent mesentery is suggested for most lesions. Five year survival following resection approximates 50% in reported series.

Adult↗

Loss of thick filaments from fast-twitch glucolytic muscle fibers of the pigeon pectoralis after chronic administration of dantrolene sodium.

Adult pigeons received dantrolene sodium, a skeletal muscle relaxant which blocks the release of calcium during excitation-contraction coupling, for 12 to 16 weeks. The pectoralis muscles of these birds were analyzed for changes occurring in the various fiber types of the muscle. Both histochemistry (ATPase and SDH activity) and electron microscopy (mitochondrial and lipid volume percentages) differentiated two fiber types. The two fiber-types consisted of fast-twitch glycolytic fibers (FG) and fast-twitch oxidative-glycolytic (FOG) fibers. After dantrolene treatment some FG fibers showed little or no ATPase activity. Dantrolene treatment also produced a disappearance of thick filaments in some FG fibers. We infer that the fibers without thick filaments are the ones lacking ATPase activity. The FOG fibers were nearly normal. Since drug-fed birds lose weight, a few birds were starved to determine whether the filament loss was related solely to the bird's loss in weight. No fibers in starved birds showed reduced ATPase activity or loss of thick filaments. In fibers that showed thick filament disappearance, the I-bands remained organized and intact, suggesting that the I-band maintains its integrity without interaction with the thick filaments. Changes in activity patterns may cause loss of thick filaments by inhibiting either their synthesis or assembly.

Adenosine Triphosphatases↗

Fixation of cadaver eyes for surgical practice.

Cadaver eyes for surgical practice may be prepared by melting No. 7 dental wax in a 1-ounce medicine glass and fixing the globe with melted dental wax. The preparation is then placed in a styrofoam wig stand with openings prepared for the medicine glass.

Cadaver↗

Capturing clinical expertise. A computer program that considers clinical responses to digitalis.

The administration of digitalis by experienced cardiologists has been examined and a prototypical computer program has been developed which captures portions of their expertise. The new program first constructs a patient-specific model upon which to base the determination of dosage and then uses feedback information about a variety of clinical aspects of the patient's response to modify its recommendations. The model reflects both the program's knowledge of pharmacokinetics and those special features of the patient's condition which may alter his response to therapy. The program makes assessments of the therapeutic and the toxic effects of digitalis on the patient, and bases its subsequent recommendations on the "therapeutic-toxic" state which best describes the evolving clinical situation. A clinical trial was performed in which the program "followed" a series of patients managed by clinicians on a cardiology service. That trial demonstrated the feasibility of this type of program in dealing with acutely ill patients, even those who have increased sensitivity to the toxic effects of digitalis. Each patient in the trial in whom toxicity developed had received more digitalis than would have been recommended by the program. This approach to automated clinical consultation should eventually provide a technology for the distribution of clinical expertise.

Aged↗