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Biomedical subjects

M Schwartz

Publications and source records attributed to M Schwartz.

At least 397 records · Page 22Linked to original sources
PubMed1993

Dose and temporal parameters in delaying injured optic nerve degeneration by low-energy laser irradiation.

Low-energy laser irradiation has been reported to postpone the degenerative processes in crushed optic nerves of rats, which are part of the nonregenerable mammalian central nervous system. In the present study, we evaluated the optimal irradiation parameters for this purpose. Optic nerves of 141 rats were subjected to crush injury and then irradiated through the eye, starting at different points of time before or after the injury, for different durations and periods, using various intensities of either helium-neon laser or noncoherent infrared light (904 nm). The effect was evaluated by measurements of the compound action potentials of the nerve segments between the site of injury and the optic chiasm. The compound action potential amplitude of the crushed nonirradiated nerves, as measured 2 weeks after the injury, was found to be 0.51 +/- 0.30 mV, in contrast to 3.10 +/- 1.03 mV measured in 232 normal nerves. Irradiation with a 10.5 mW helium-neon laser for 2 and 3 min once a day for 14 consecutive days resulted in maximal preservation of action potentials (1.78 +/- 0.72 and 1.95 +/- 0.71 mV, respectively). Irradiations beginning immediately prior to the injury were as effective as irradiations beginning soon after it. Irradiations for longer than 3 min or twice a day aggravated the damage. Noncoherent infrared light was ineffective or adversely affected the injured nerves. Our experiments suggest that optimal delay of posttraumatic optic nerve degeneration in rats is attainable with 10.5 mW helium-neon laser irradiations for 2 or 3 min once a day for 14 consecutive days.

Action Potentials↗
PubMed1993

Adherence and psychological adjustment among women at high risk for breast cancer.

Increasingly, women with a positive family history of breast cancer are being targeted for cancer prevention and control efforts. Two findings have been demonstrated consistently across studies of this high risk population. First, these women often have high levels of psychological distress, as well as persistent and intrusive worries about developing breast cancer. Second, despite their increased risk for developing breast cancer, a substantial proportion of these women do not adhere to recommended breast cancer screening guidelines. There is growing evidence that psychological distress is an important barrier to adherence among high risk women. Despite this, little is known about how to intervene to improve psychological adjustment and adherence in this population. In the present paper, we review the literature on adherence and psychological adjustment in women who are at increased risk for breast cancer because of a positive family history of disease. This review provides the basis for a discussion of potential intervention strategies designed to increase adherence and reduce psychological distress in this population. Finally, we present some of the psychological implications of recent developments in genetic testing for breast cancer susceptibility.

Adult↗
PubMed1993

Lidocaine prophylaxis in coronary revascularization patients: a randomized, prospective trial.

Life-threatening ventricular ectopy can occur after cardiac operations. The actual incidence of ventricular ectopy and the ability to prevent it by the routine prophylactic use of lidocaine hydrochloride have not been established. We performed a double-blind, randomized, prospective trial involving 109 patients undergoing elective coronary artery revascularization. Patients received either lidocaine (n = 54) or a placebo (n = 55) after separation from bypass. A Holter monitor was affixed to each patient for subsequent review, and bedside intensive-care monitors with alarms were used for "real-time" surveillance. The code was broken when potentially malignant ventricular ectopy or side effects attributable to the study drug were noted. Three lidocaine patients and 2 placebo patients were dropped from the study because of hemodynamic instability or bleeding. Of the remaining 104 patients, the code was broken in 12 (24%) of the 51 in the lidocaine group (9 for ectopy and 3 for mental status changes) and 10 (19%) of the 53 in the placebo group (all for ectopy) (p = not significant). Twenty-four-hour Holter monitor evaluation demonstrated occasional ventricular ectopy in all patients and nonsustained ventricular tachycardia in 28% in the lidocaine group and 48% in the placebo group (p = not significant). The mean number of runs of ventricular tachycardia per patient was 0.53 in the lidocaine group and 1.6 in the placebo group (p = 0.035). There were no significant differences in terms of other ventricular ectopy, morbidity, or mortality. No ventricular fibrillation occurred in either group.(ABSTRACT TRUNCATED AT 250 WORDS)

Arrhythmias, Cardiac↗
PubMed1993

New light on nerve regeneration in the mammalian nervous system.

It has long been known that while damaged nerves of the peripheral nervous system in mammals are able to regenerate, this does not occur in the central nervous system. Recent studies have shown that a chemical factor present in regenerating fish optic nerves facilitates regeneration of nerve axons in rodents. Further research encourages the hope that this may ultimately lead to the successful treatment of nerve damage in humans.

Animals↗
PubMed1993

Intralesional interferon-alpha and zidovudine in epidemic Kaposi's sarcoma.

BACKGROUND: Kaposi's sarcoma (KS) is the most common neoplasm in patients with acquired immunodeficiency syndrome (AIDS). To date, no therapy has proved to be consistently effective. OBJECTIVE: The purpose of this study was to evaluate the efficacy of intralesional interferon-alpha in patients with epidemic KS who were taking zidovudine. METHODS: Up to five lesions in each of 14 patients entered into the study were injected with 1 million U of interferon-alpha three times weekly for 6 weeks. Sterile water was used as a placebo control. The median zidovudine dose was 500 mg/day. The median CD4 count was 23/microliters. RESULTS: Of 14 patients evaluated, 13 of 14 (93%) showed a clinical complete response (CR) or partial response (PR) to therapy. Of 54 lesions injected, 41 (76%) showed a CR and 5 (9%) showed a PR, which resulted in an overall response rate of 85%. CONCLUSION: Intralesional interferon-alpha produced a high response rate in injected lesions of KS, but it failed to demonstrate superior efficacy over the placebo.

Acquired Immunodeficiency Syndrome↗
PubMed1993

cDNA clones from fish optic nerve.

1. The present review describes the results of a cloning that was successfully employed in the study of optic nerve regeneration in fish. 2. Three intermediate filaments (IFs) expressed by the glial fish optic nerve were cloned. 3. By the use of this approach it was possible to resolve the controversial question of whether glial fibrillary acidic protein (GFAP) is expressed in the fish optic nerve. 4. Moreover, as a result of the information that emerged from the cloning, it was possible to raise well-characterized monospecific antibodies and successfully exploit them in order to determine glial cell maturation, lineage and plasticity, monitor the glial cell response to injury of the fish optic nerve, and compare it to that of a non-regenerative system.

Amino Acid Sequence↗
PubMed1993

Cavernous artery obstruction following blunt trauma to the penis.

Erectile dysfunction following blunt trauma to the erect penis usually is associated with an injury to the tunica albuginea of the corpus cavernosum. We recently identified 2 patients with erectile dysfunction following bending of the penis during coitus whose only abnormality after a complete evaluation, including penile angiography, was a deep cavernous artery injury. We suggest that during examination of patients with erectile dysfunction following blunt injury to the erect penis a complete vascular evaluation, including penile angiography, may be necessary to detect an unrecognized injury to the deep cavernous arteries.

Adult↗
PubMed1993

Pulmonary migration of coils inserted for treatment of erectile dysfunction caused by venous leakage.

Embolization of penile veins by coils and/or detachable balloons has been reported as a possible effective form of treatment of venogenic erectile dysfunction. The major appeal for this avenue of therapy in these patients is the reported low morbidity and negligible rate of complications compared to an open operation. We describe a case of asymptomatic pulmonary migration of a coil placed for venous leakage in a patient in whom the procedure was conducted through the femoral vein rather than the deep dorsal vein. We conclude that patients undergoing coil embolization for venous leakage should be appraised of the potential for coil migration.

Adult↗
PubMed1993

Haplotype analysis to determine the position of a mutation among closely linked DNA markers.

Positional cloning involves first finding linkage between an inherited phenotype (such as a disease) and a DNA marker, followed by the use of a variety of physical and genetic mapping techniques to move from linkage to mutation. If there is a founder effect within a population, crossovers are often rare between the mutation causing the phenotype and closely situated markers and increasing disequilibrium may be observed as the site of the mutation is approached. Standard coefficients of disequilibrium may, however, be insensitive to the relative position of close markers and the mutation, because they depend upon allele frequencies in the normal population compared to those of the founder chromosome. Using cystic fibrosis in European populations as a model system, alternative methods for determining the position of a mutation are discussed. These include haplotype parsimony and three-way interval likelihood analysis. Both methods predict the location of the major CF mutation accurately from a real set of more than 600 European CF chromosomes.

Alleles↗
PubMed1993

Gangliosides attenuate axonal loss after optic nerve injury.

Gangliosides have been shown to be capable of protecting nerve tissue from mechanical and biochemical insults and promoting their repair. The present study provides morphologic evidence that monosialogangliosides attenuate the degenerative process at the distal stump of the rat optic nerve after crush injury. Injured rat optic nerves were treated for 7 days after injury with daily intraperitoneal injections of monosialogangliosides (30 mg/kg/day), and compared with untreated injured controls with respect to the number of viable axons 2 and 4 weeks after injury, as indicated by transmission electron microscopy. After 2 weeks, the mean number of viable axons in the treated optic nerves (n = 5) was slightly higher than in the controls (n = 5). Four weeks after injury, although the absolute number in both the experimental and the control groups had dropped, it was about seven-fold higher in the treated animals (1696 +/- 1149, n = 7) than in the untreated animals (216 +/- 65, n = 6); this difference was statistically significant. These findings, which offer some insight as to how monosialogangliosides affect injured nerves, may have important implications for treatment in cases of optic nerve injury.

Animals↗
PubMed1993

FK506 versus cyclosporine as primary immunosuppressive agent for orthotopic liver allograft recipients. Histologic and immunopathologic observations.

We investigated possible explanations for the common occurrence of perivenular lesions in liver allografts of patients on FK506 within a few weeks to several months after OLT. Hematoxylin and eosin-stained sections of pre- and postperfusion biopsy specimens and day 7 post-transplant protocol biopsy specimens from 31 patients, randomly assigned to either FK506 or CsA as primary immunosuppressive agent, were reviewed, and immunohistochemical stains for HLA-DR antigen and S-100 protein were performed by the avidin-biotin peroxidase complex method. The histologic features of cellular rejection in the portal tracts of day 7 posttransplant allograft biopsy specimens from patients on FK506 were milder than those from patients on CsA. Immunohistochemical stains for HLA-DR showed intense positivity in a variety of cell types in day 7 posttransplant specimens from both groups, including sinusoidal-lining cells, bile duct epithelial cells, vascular endothelial cells, inflammatory cells, and occasional injured hepatocytes. Although diffuse lobular staining was seen in the majority of cases in both groups, either with or without rejection, liver biopsy specimens from patients on FK506 showed concentration of positively stained cells in perivenular regions more often, and at a lower overall histologic grade of rejection, than specimens from patients on CsA. There were no differences in the number and distribution of S-100 protein-positive dendritic APC between biopsy specimens from FK506 versus CsA-treated patients, or between specimens with and without cellular rejection in either group. It is suggested that the development of perivenular injury, which is seen frequently in allograft biopsy specimens from patients on FK506 obtained at various intervals after transplantation, may be related to drug toxicity rather than to the process of allograft rejection.

Cyclosporine↗
PubMed1993

Frequency of the delta F508 and exon 11 mutations in Norwegian cystic fibrosis patients.

We have searched for the delta F508 mutation in 77 Norwegian cystic fibrosis patients. Of the 154 chromosomes tested, 93 (60%) carried the delta F508 mutation. Haplotypes at the D7S23 locus (KM19 and XV2C markers) were determined. Of 81 chromosomes with the F508 mutation, the B haplotype was found on 77. We found three patients with the G551D and one patient with the R553X mutation in exon 11 of the CFTR locus.

Cystic Fibrosis↗
PubMed1993

Diabetes mellitus in cystic fibrosis: genetic and immunological markers.

Family history, as well as genetic and immunological markers of diabetes mellitus, were studied in cystic fibrosis (CF) patients with and without diabetes mellitus. Positive family history of diabetes mellitus in first-degree relatives was found in only 6 of 210 (3%) CF patients, with no difference between non-diabetic and diabetic patients. The frequency distributions of the HLA types DR3, DR4 and DR3/4, which normally confer susceptibility to insulin-dependent diabetes mellitus and of HLA-DR2, which normally confers resistance to insulin-dependent diabetes mellitus, were not different in non-diabetic CF patients, diabetic CF patients and normal subjects. The genotypic frequencies of tumor necrosis factor-beta and of heat shock protein 70, located within the HLA region on chromosome 6, in CF patients with diabetes were not different from those in patients with insulin-dependent diabetes mellitus, while non-diabetic CF patients and normal subjects shared other patterns. The frequencies of the interleukin-1 beta alleles, located on chromosome 2, were not different in non-diabetic and diabetic CF patients, insulin-dependent diabetic patients and normal subjects. Islet cell cytoplasmic antibodies, measured before, at and after the diagnosis of diabetes in 33 diabetic CF patients and in 32 matched non-diabetic CF patients, were detected in only 2 of 236 (0.8%) serum samples: in a pre-diabetic patient and in a non-diabetic control patient. Birth weights were not different in diabetic and non-diabetic CF patients, arguing against the importance of the intrauterine environment as a determinant in the transmission of diabetes mellitus in CF patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Effect of inhibitors of gastric secretion on polarization of gastric potential by voltage clamping.

Voltage clamping across the frog gastric mucosa, nutrient positive to secretory, results in an increase in the open-circuit potential difference (OCPD). The increase in OCPD, or polarization, induced by voltage clamping could be caused by a redistribution of ions across the plasma membrane or by a polarization of pump electromotive forces, such as the Na(+)-K(+)-adenosinetriphosphatase (ATPase) located in the nutrient (serosal) membrane or the proton pump located in the secretory (luminal) membrane. The polarization induced by voltage clamping was not affected by removing Cl- and Na+ or by increasing the K+ concentration to 79 mM but was markedly reduced by placing in the nutrient solution 10(-3) M famotidine or 10(-4) M omeprazole. These data suggest that there is a strong contribution of the proton pump to the polarization induced by voltage clamping with some contribution of ion redistribution and/or the Na(+)-K(+)-ATPase. The data support the electrogenicity of the proton pump.

Animals↗
PubMed1993

Tardive dyskinesia in northern Israel: preliminary study.

Tardive dyskinesia (TD) is an iatrogenic syndrome caused by long-term treatment with neuroleptics and is characterized by abnormal involuntary movements in the orofacial region, lingual dyskinesia and in some cases dyskinesia also in the extremities, head and trunk. In the present study we found 20% TD in chronic-neuroleptic-treated patients with a significantly greater prevalence in females (27% of the total population), and a higher frequency in older patients. In males, patients who received electroconvulsive therapy had a significantly lower prevalence of TD. 23 patients had seizures; 7 of these suffered from TD, all of them female.

Adult↗
PubMed1993

Screening for carriers of cystic fibrosis among pregnant women: a pilot study.

Cystic fibrosis (CF) is one of the most common hereditary disorders among Caucasians. In such populations a highly prevalent mutation causing CF, delta F508, has been identified. It comprises 88% of Danish CF mutations. This mutation and five others account for 90% of all CF mutations, making carrier screening on a population basis worthy of consideration. We have therefore performed a pilot screening programme for CF carriers among pregnant women. From June 1, 1990, for the following 2 years, 6,599 women were tested: 172 were heterozygous for delta F508. Three of 162 partners tested were also heterozygous for delta F508. After genetic counselling all three couples at risk for having a child with CF requested prenatal diagnosis. One fetus was homozygous for delta F508, and the pregnancy was terminated. With currently available techniques, the screening programme presented here causes no practical problems, and screening for CF carriers can easily be run on a larger scale.

Adolescent↗
PubMed1993

Prostate-specific antigen as a measure of disease outcome in metastatic hormone-refractory prostate cancer.

PURPOSE: To evaluate the prognostic significance of pretreatment parameters and posttherapy declines in prostate-specific antigen (PSA) in relation to the survival of patients with hormone-refractory prostate cancer. PATIENTS AND METHODS: One hundred ten assessable patients treated on seven sequential protocols at Memorial Sloan-Kettering Cancer Center (MSKCC) for hormone-refractory prostate cancer were evaluated for 29 different pretherapy and posttherapy parameters, including a posttherapy decline in PSA of 50% and 80% from baseline. RESULTS: In the univariate analysis, initial Karnofsky performance status (KPS) > or = 80% was associated with a favorable outcome (P = .005), while age, extent of disease on bone scan, and individual sites of metastatic disease were not significant. No difference in survival was observed between patients with measurable or assessable (bone only) disease. Initial hemoglobin (HGB; P = .0012), alkaline phosphatase (ALK; P = .0015), and lactate dehydrogenase (LDH; P = .0002) levels were significant discriminators, while the initial PSA was not. Using a landmark analysis, a significantly longer median survival rate was observed for patients with a > or = 50% decline in PSA (median not reached) versus patients with a less than 50% decline in PSA (median, 8.6 months; P = .0001). Multivariate analysis using the Cox proportional hazards model showed that a > or = 50% decline in PSA (P = .0004) and the natural log of LDH (P = .0001) were the two most significant variables predicting survival. The model was confirmed on an independent data set from the Norwegian Radium Hospital (NRH) in Oslo, Norway. CONCLUSION: The results suggest that posttherapy PSA declines can be used as a surrogate end point to evaluate new agents in hormone-refractory prostate cancer. The criteria for response need prospective validation in phase III trials.

Aged↗