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Biomedical subjects

M Waxman

Publications and source records attributed to M Waxman.

At least 19 recordsLinked to original sources
PubMed1992

Use of telemetry functions in the assessment of implanted antitachycardia device efficacy.

Twenty patients (aged 50 +/- 21 years and mean left ventricular ejection fraction 37 +/- 17%) with recurrent ventricular arrhythmias were treated with an investigational, implantable combined antitachycardia-pacing cardioverter defibrillator. The device's telemetry capabilities include both stored (1-second snapshots) and real-time display of endocardial and device-circuit signals. The device can store these before, during and after up to 50 tachycardia and antitachycardia pacing episodes. All stored events are indexed to a 24-hour internal clock. During 10.1 +/- 5.1 months of follow-up, the device was used in 11 of 20 patients. In the entire group, antitachycardia pacing was activated on 44 +/- 14 occasions per patient (total 874) and shock delivery occurred on 8 +/- 14 occasions per patient (total 156). Reconstruction by stored telemetry of all device-therapy episodes was possible. Twenty-six percent of all shocks delivered were not appropriate and were due to atrial arrhythmias in 2 patients and dysfunction of the sensing lead in 3. The absence of a relation between symptoms and appropriate shock delivery was documented in 1 patient. Antitachycardia pace acceleration occurred in 5.3% of cases; 7% of attempts at pacing were unsuccessful and needed shock therapy. It is concluded that the enhanced telemetry available in newer antitachycardia devices enables more accurate assessment of device use and enhances diagnosis of inappropriate therapy delivery.

Electric Countershock↗
PubMed1992

A follow-along study of participants in a longitudinal transition program for youths with mild disabilities.

Descriptive data are presented on the employment patterns of youths with mild disabilities who participated in a transition program with an intensive postsecondary component. Data on employment rates, positive and negative job changes, participation in continuing education, and access to benefit packages are reported for 94 youths who participated in the program over a 4-year period. Program participants had favorable outcomes when compared with a national sample, but they stabilized at an entry level of work participation. Their rates of entry into postsecondary education were also greater than the national sample, but advances were nominal.

Adolescent↗
PubMed1990

Evidence of a role for protein kinase C in epidermal growth factor-induced prostaglandin E2 synthesis in amnion cells.

Human amnion cells synthesize and release prostaglandin E2 in response to epidermal growth factor. The protein kinase C activator, phorbol 12-myristate, 13-acetate also stimulates amnion cell prostaglandin E2 synthesis. We used a human amnion cell line (WISH) to conduct in vitro experiments to investigate a potential role of protein kinase C in the signal transduction pathway leading to epidermal growth factor-induced prostaglandin E2 production. Pretreatment of cultured amnion cells with a low, nonstimulating dose of phorbol 12-myristate, 13-acetate potentiated the action of epidermal growth factor in causing prostaglandin E2 production as measured by radioimmunoassay. The protein kinase C-selective inhibitor staurosporine inhibited epidermal growth factor-induced prostaglandin E2 production, further suggesting a role for protein kinase C in epidermal growth factor action. Experiments were conducted in which amnion cells were rendered protein kinase C-deficient by chronic exposure to phorbol ester, which has been shown to down-regulate the enzyme. In these cells, epidermal growth factor caused prostaglandin E2 synthesis at levels comparable to native (non-protein kinase C-deficient) cells. We conclude that protein kinase C plays a more modulatory than direct role in the epidermal growth factor signal transduction cascade that leads to prostaglandin E2 production by amnion cells. We propose a bifurcating transduction scheme in which, under conditions of protein kinase C inactivation, epidermal growth factor alone causes prostaglandin E2 synthesis. When protein kinase C is activated by as yet unknown endogenous substances, the epidermal growth factor responsiveness of the amnion cells is greatly enhanced. This pathway could have important implications in a feed-forward mechanism regulating the level of prostaglandin E2 production during the onset of labor.

Alkaloids↗
PubMed1990

Opportunistic infections of the testis in the acquired immunodeficiency syndrome.

The testes of an autopsy sample of 56 patients with acquired immunodeficiency syndrome (AIDS) and systemic opportunistic infections were studied for the presence and type of testicular infection. Light-microscopic evidence of opportunistic organisms (cytomegalovirus, Mycobacterium avium-intracellulare, and Toxoplasma) was present in 22 cases (39%). Based on the prevalence and histologic features of the testicular infections and the biological characteristics of the specific organisms, the possible sexual transmission of opportunistic organisms in AIDS is discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Testicular atrophy in AIDS: a study of 57 autopsy cases.

The pertinent clinical data and histologic features of the testes in 57 autopsied acquired immunodeficiency syndrome (AIDS) patients were analyzed and compared with those of 55 age-matched control patients without AIDS. The testes of the AIDS patients showed a significantly lower degree of spermatogenesis (determined by a testicular score count), as well as more prominent thickening of the basement membrane and interstitial fibrosis when compared with the controls. While the precise cause of testicular atrophy in AIDS patients remains to be determined, the chronicity of the disease, prolonged fever, malnutrition, testicular infection, and chemotherapy are all contributing factors. Since the vast majority of the studied AIDS patients were homosexual and most control patients were heterosexual, the observed testicular changes can be ascribed to AIDS and/or homosexuality. Because of a high prevalence of sexually transmitted diseases, antisperm antibodies, and possible zinc deficiency and endocrine disorders, homosexual men appear predisposed to tubular atrophy. Conversely, AIDS-related factors, such as a direct toxic effect of the human immunodeficiency virus on germinal epithelium or as yet undetermined endocrine imbalances might exert a detrimental effect on the testis independent of homosexuality.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Testicular atrophy in homosexual AIDS patients: an immune-mediated phenomenon?

An immunopathologic analysis of the testes of 20 homosexual acquired immune deficiency syndrome (AIDS) patients was performed to investigate the hypothesis that the testicular atrophy of these patients represents an immune-mediated process. The findings were compared to those in a control group of heterosexual men without AIDS. The testes of the homosexual AIDS patients showed an overall lower degree of spermatogenesis with more prominent interstitial inflammation and thickening of the tubular basement membrane. However, direct immunofluorescence and immunoperoxidase studies failed to demonstrate significant differences in the prevalence of immune complex deposits along the tubular basement membrane in the two study groups. No electron-dense deposits were demonstrated in cases examined ultrastructurally. Therefore, this study does not support the hypothesis that the testicular atrophy of homosexual AIDS patients is a manifestation of autoimmune orchitis. Further studies are needed to elucidate the pathogenesis of the testicular atrophy in AIDS, as this appears to be a specific manifestation of the disease.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Autologous adrenal medullary transplant in progressive supranuclear palsy.

We transplanted autologous adrenal medullary cells to the caudate nucleus in 3 patients with progressive supranuclear palsy, using the method Madrazo has employed for neural transplantation in Parkinson's disease. Major and minor complications occurred post-operatively from which the patients recovered. One patient had a marked improvement in his postural stability and a decreased incidence of falling. This change was evident at 1 month after surgery and has remained for the 6 months of follow-up. Postural reflexes were not altered in the other 2 patients. There was no change in extraocular movements, speech, or the rigid-bradykinetic features of parkinsonism in any patient. Adrenal medullary transplantation has only limited efficacy in progressive supranuclear palsy.

Adrenal Medulla↗
PubMed1989

Diffuse neurofibroma of the pylorus: a cause of gastric outlet obstruction.

We describe a benign diffuse neurofibroma of the pylorus, unassociated with von Recklinghausen's neurofibromatosis, which was a cause of pyloric stenosis; epigastric discomfort, vomiting, and weight loss of 60 lb were the most prominent symptoms. Partial gastrectomy resulted in a cure. The literature on nerve-sheath tumors of the stomach is reviewed.

Aged↗
PubMed1987

Hepatic tissue in gastroscopic biopsy: evidence of hepatic penetration by peptic ulcer.

We describe a patient with peptic ulcer of the stomach penetrating into the liver, in whom diagnosis was made by histological examination of the gastroscopic biopsy. The liver tissue affected by this local "peptic hepatitis" displayed marked inflammatory and regeneratory atypia that could raise suspicion of an adenocarcinoma. The possibility of finding liver cells and tissue (or pancreatic and splenic tissues) in the gastric biopsy and brushing/washing material should be kept in mind in cases of large peptic ulcers.

Gastroscopy↗
PubMed1986

Mucosal destruction and regeneration of the colon by local hyperthermia. An experimental preliminary study.

An experimental model has been developed to produce colonic mucosal destruction followed by regeneration. The canine model consists of a defunctioned portion of the large intestine which has been subjected to water at a temperature of 125 degrees F for 7 hours. Colonic specimens were harvested at different periods of up to six weeks and studied macro- and microscopically. It has been shown that it is possible to achieve significant mucosal destruction and regeneration. Possible adaptation to clinical states is presented and discussed.

Absorption↗
PubMed1986

Primary malignant lymphoma of the anorectum in homosexual men.

Two homosexual men presented with primary malignant lymphomas of the anorectum. Each patient presented with a painful mass, diagnosed by biopsy and immunologic cell marker studies. One patient, who had a reversed T4/T8 cell ratio, developed a local relapse of the tumor 11 months after radiotherapy, and Pneumocystis carinii pneumonia. The other patient, with a normal T4/T8 ratio, remained lymphoma-free and without evidence of opportunistic infection 25 months after combined chemotherapy and radiotherapy. Anorectal pathologic findings in homosexual men includes proctitis, inflammatory stricture, fissure, or anal warts. Malignant anorectal diseases, such as Kaposi's sarcoma, and cloacogenic or squamous cell carcinomas have been described in homosexual men. Primary malignant lymphoma of the anorectum is rare in both the homosexual and general populations.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Melanocyte colonization of adenocarcinoma arising in an ovarian dermoid.

An adenocarcinoma which arose in a dermoid cyst of the ovary displayed areas of melanocyte colonization and pigmentation. Ultrastructural study revealed the presence of epithelial tumour cells and melanocytes; many tumour cells contained compound melanosomes, but not premelanosomes, suggesting transfer of melanin from melanocytes to tumour cells. Melanocyte colonization of malignant tumours is a curious phenomenon the significance of which remains to be elucidated.

Adenocarcinoma↗