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Biomedical subjects

S Hoffman

Publications and source records attributed to S Hoffman.

At least 181 records · Page 10Linked to original sources
PubMed1982

Chemical characterization of a neural cell adhesion molecule purified from embryonic brain membranes.

A neural cell adhesion molecule (N-CAM) was purified in milligram quantities from detergent extracts of embryonic chick brain membranes. N-CAM has an unusual carbohydrate content and structure, is polydisperse in solution, and is associated with proteolytic activity leading to its spontaneous cleavage. The carbohydrate composition of N-CAM includes 13 mol of sialic acid but only 1.4 mol of galactose/100 mol of amino acids, suggesting the presence of a sialic acid to protein linkage not previously observed in higher organisms. N-CAM appears to be an integral membrane protein in that its extraction from membranes required detergent. Although soluble, the purified molecule was aggregated (Mr = 0.5 to 1.2 X 10(6)) and polydisperse in detergent-free solutions. N-CAM from brain also migrated as a broad but continuously stained region from Mr = 200,000 to Mr = 250,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis; the molecule from retina was similar but had a somewhat faster mobility. Desialation of N-CAM did not significantly change its behavior in solution, but converted both brain and retinal N-CAM to components migrating on sodium dodecyl sulfate-polyacrylamide gel electrophoresis as material of about Mr = 140,000. Despite the apparent heterogeneity, amino acid sequence analysis and comparison of proteolytic fragments suggest that all forms of the glycoprotein are derived from the same polypeptide chain. On prolonged incubation at neutral pH, N-CAM undergoes apparent proteolysis to yield a polypeptide that contains little sialic acid and has a Mr = 65,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, a separate sialic acid-rich component, and a variety of small peptides. The 65,000-dalton polypeptide appeared to contain all of the antigenic determinants of intact N-CAM that neutralize the adhesion-blocking ability of anti-retinal cell Fab' fragments.

Amino Acid Sequence↗
PubMed1982

Q-T prolongation and polymorphous ("torsade de pointes") ventricular arrhythmias associated with organophosphorus insecticide poisoning.

It is not generally appreciated in the Western world that organophosphorus poisoning may be associated with a serious and often fatal cardiac complication: Q-T interval prolongation with malignant ventricular arrhythmias of the "torsade de pointes" type. This insidious complication may lead to delayed, sudden death after the patients appears to be well on the way to recovery from the other, more dramatic respiratory and neurologic symptoms. In this study 15 patients with organophosphorus poisoning are described. Q-T prolongation was observed in 14 and malignant tachyarrhythmias in 6. In view of the dismal prognosis of these patients, ventricular pacing, previously used with success in other conditions associated with this syndrome, was tried in four patients and successfully shortened the Q-T interval and eliminated the arrhythmias. Isoproterenol did the same in a fifth patient. Awareness of this lethal, but preventable complication of organophosphorus poisoning is called for. Careful electrocardiographic monitoring is necessary until the Q-T interval returns to normal. Electrical pacing appears to be the treatment of choice for the tachyarrhythmias.

Adolescent↗
PubMed1982

Binding properties of a cell adhesion molecule from neural tissue.

We have previously identified and purified a cell surface glycoprotein from retina and brain, called neural cell adhesion molecule or N-CAM, that appears to be involved in neural cell--cell adhesion, the fasciculation of neurites, and the formation of normal tissue patterns in the retina. The present studies reveal that artificial vesicles containing lipid and purified N-CAM bind to different cell types with a specificity similar to that of nerve cells. The same results were obtained with soluble N-CAM that had been briefly exposed to pH 3. In both cases the binding altered the rate of aggregation of neural cells and, like cell--cell adhesion, was inhibited by antibodies against N-CAM. The results support the proposal that N-CAM is a ligand in the formation of bonds between nerve cell membranes. Moreover, results of studies of vesicle--vesicle interactions and of N-CAM binding to cells coated with anti-(N-CAM) Fab' fragments were consistent with the idea that the N-CAM molecules on different cells may interact directly to form cell--cell bonds.

Animals↗
PubMed1982

A reduction mammaplasty with legal implications.

The case of a reduction mammaplasty is presented in which the result was unsatisfactory because the nipples were located too high. The patient instituted a lawsuit against her plastic surgeon but lost the case. The cause and prevention of this poor result are discussed. The legal implications are analyzed by an attorney.

Adult↗
PubMed1982

An analysis of types and costs of health care services provided to an elderly inner-city population.

The challenge facing national policymakers is to provide health care that is comprehensive and cost-effective to our nation's growing population of elderly people. A solution worthy of consideration is the use of health maintenance organizations (HMOs) in this capacity. An analysis of the services provided by a multidisciplinary health care system to 150 inner-city elderly, many of whom were "homebound," reversal 1) this population is not homogeneous with respect to severity of disease and service utilization, and 2) a total mean cost per individual per year of $2,021.34 covers: physician, nursing, and social service home visits; visiting nurse, homemakers, home health aide, occupational therapy and physical therapy services; outpatient, laboratory and medication costs. These findings suggest that while costs for those over 65 are many times the per capita costs of younger enrollees, these costs may be significantly less than the costs of institutional care. Further investigation of the costs of maintaining low-income inner-city old, as well as other elderly populations, at home is vital to planning for future long-term care.

Aged↗
PubMed1982

Nipple necrosis.

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Breast↗
PubMed1981

Naproxen sodium, aspirin, and placebo in primary dysmenorrhea. Reduction of pain and blood levels of prostaglandin F2-alpha metabolite.

In a double-blind, crossover study of 32 women with primary dysmenorrhea, the analgesic efficacy of naproxen sodium was compared to that of aspirin and placebo. The treatment started 1 to 5 days before the onset of menses and continued for 3 to 5 days. At the same time, a radioimmunoassay established concentrations of 13,14-dihydro-15-keto-prostaglandin F2-alpha, a prostaglandin F2-alpha metabolite (PGF-M) in blood samples obtained from before the treatment and on the first day of menses. In affording pain relief, naproxen sodium was superior to aspirin (p = 0.02) and placebo (p = 0.002); however, aspirin was not superior to placebo (p = 0.05). During naproxen sodium treatment, the patients' daily activities were less impaired than during both the aspirin and the placebo treatment courses. During naproxen sodium treatment, the mean blood PGF-M levels decreased by 73.5%, from a mean of 50.5 to 13.4 pg/ml; during aspirin treatment they decreased by 31.2%, from a mean of 44.2 to 30.4 pg/ml; during placebo treatment, an increase of 13.6% was observed, from a mean of 46.3 to 52.6 pg/ml. The PGF-M decrease during the naproxen sodium treatment was significantly more prominent than that during both aspirin and placebo treatments (p = 0.0001). Changes caused by aspirin treatment were significantly different from those occurring during the placebo treatment (p = 0.001). The study confirms that at the doses utilized in this study the analgesic properties of naproxen sodium are superior to those of the more conventional prostaglandin synthetase inhibitor, aspirin, and that pain relief is related to the inhibition of prostaglandin synthesis.

Activities of Daily Living↗
PubMed1981

Mammoplasty for tubular breasts.

Tubular or nipple breasts are descriptive of an unusual deformity in which a hypoplastic mammary gland is situated under a stretched out areola, giving the breast a tubular shape. Six patients, age 17 to 21 years, have undergone surgical correction of this deformity. The one-stage procedure involves excision of excess areola, augmentation through the areolar incision, correction of asymmetry by means of asymmetric implants, and cruciate incisions on the posterior aspect of the breast to improve the contoural defect. The complication rate has been no greater than that of routine augmentation, and patient satisfaction has been good.

Adolescent↗
PubMed1981

Fibrous histiocytomas of the oral mucosa.

The oral lesions reported in this article fall into the first category of benign fibrous histiocytomas analogous to those which occur on sun-exposed skin surfaces of young objects. The ages of the patients, the histologic features and the history of traumatic episodes, as well as their biologic behaviors on follow-up, are all features compatible with those benign lesions which occur in the skin. According to the information presented in these cases, there is stronger evidence that the lesions of the oral mucosa, like their dermatologic counterparts, are representative of reactive inflammatory processes rather than neoplastic processes. It is of considerable interest that in both cases reported here the patients were children whose lesions developed following significantly severe traumatic episodes. Also of interest is the finding that the lesions healed with no recurrences or complications, even though in one of the cases it was not completely removed. These findings are in agreement with other reports of such lesions which have occurred in the head and neck regions of children and young adults. From the over-all information obtained in the literature review regarding the biologic behavior of benign fibro-histiocytic lesions, the collected data seem to indicate that lesions of the skin and superfacial mucosal surfaces which occur in children and young adults are proliferative, reactive lesions and infection, or irradiation. Systemic, visceral, or deep-seated lesions in the lower extremities appear to be true neoplasms and their prognoses must be considered as guarded.

Child↗
PubMed1981

Single-injection epidural anesthesia with bupivacaine and morphine for prostatectomy.

In 30 patients having prostatectomies, 15 patients (group I) given single-injection epidural anesthesia using bupivacaine and morphine (4 mg) were compared with 15 patients (group II) given epidural bupivacaine without morphine. Patients in group I had pain relief for a mean duration of 27 hours and did not request additional analgesia. Patients receiving bupivacaine alone had pain relief for an average of 6.2 hours after surgery; all required narcotics postoperatively. It was concluded that the addition of 4 mg of morphine to the local anesthetic for epidural anesthesia in patients having prostatectomies results in excellent postoperative analgesia.

Aged↗