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Biomedical subjects

M Bernstein

Publications and source records attributed to M Bernstein.

At least 217 records · Page 12Linked to original sources
PubMed1985

Radiation brain damage induced by interstitial 125I sources: a canine model evaluated by quantitative computed tomography.

The canine brain is a good model of the human brain for studying radiation damage after megavoltage x-irradiation for brain tumors. We have further developed this model to study radiation damage induced by high activity interstitial 125I sources. Removable 125I sources were implanted in normal canine brains, and doses of 1,000 to 10,000 rads were delivered to a reference point at a 10-mm radius from the source; dose rates were 35 to 40 rads/hour at the reference point. Serial quantitative analysis of tissue damage (tissue density and contrast enhancement) was done using computed tomographic scanning up to 6 months after implantation and was compared to histopathological findings after the animals were killed. At doses greater than 19,000 rads (i.e., inside the reference point), frank coagulation necrosis was observed. Pronounced vessel-related changes, manifest as areas of contrast enhancement, corresponded to tissues receiving a minimum of 6,000 rads and a maximum of 19,000 rads. These results indicate that this model can be used in serial noninvasive studies to quantify the development of damage induced by interstitial irradiation and to provide dose-response information in individual animals.

Animals↗
PubMed1984

An internal standard for porphyrin analysis.

The routine clinical analysis of the porphyrin precursors of heme requires an internal standard to determine the efficiency of the analytical procedure used. 2-Vinyl-4-hydroxymethyldeuteroporphyrin IX has been prepared as an internal standard. Its application to porphyrin analysis has been demonstrated using high-performance liquid chromatographic resolution of the uro- to protoporphyrins in normal and porphyric urine.

Chromatography, High Pressure Liquid↗
PubMed1984

Rapid determination of 5-fluorocytosine levels in blood.

Levels of 5-fluorocytosine in blood were rapidly calculated by determining the amount of competition in the creatinine iminohydrolase (creatinine deiminase; EC 3.5.4.21) assay for creatinine with the Kodak Ektachem system (Eastman Kodak Co., Rochester, N.Y.). The correlation with bioassay values was extremely high (r = 0.982). Standards and samples were highly stable over time.

Aminohydrolases↗
PubMed1984

Cerebral hyperperfusion after carotid endarterectomy: a cause of cerebral hemorrhage.

Correction of a very high grade carotid stenosis by endarterectomy in a normotensive man was followed by the development of severe unilateral head, eye, and face pain, seizures, and on the 6th day a fatal intracerebral hemorrhage. Autopsy revealed changes in the cerebral hemisphere ipsilateral to the endarterectomy that resembled the changes seen in malignant hypertension, whereas the opposite hemisphere was normal. These changes included hypercellularity and edema of arterial and arteriolar walls, with necrosis, extravasation of erythrocytes, and exudation of fibrin. We propose that the clinical and pathological features in this case were due to relative hyperperfusion of a cerebral hemisphere in which autoregulation had been impaired because of preoperative chronic hypoperfusion with chronic maximal dilatation of its blood vessels. This state of relative hyperperfusion is probably similar to the normal perfusion pressure breakthrough that occasionally occurs after the resection of cerebral arteriovenous malformations. It is similar to the breakthrough perfusion that occurs in severely hypertensive patients and results in hypertensive encephalopathy.

Arterioles↗
PubMed1984

Radiation-induced cerebellar chondrosarcoma. Case report.

The authors report a case of chondrosarcoma arising in the cerebellum 16 years after treatment of a cerebellar malignant astrocytoma by subtotal resection and irradiation. It is thought that the chondrosarcoma arising within the intracranial cavity was a probable consequence of previous ionizing radiation.

Adult↗
PubMed1984

Pituitary apoplexy associated with a triple bolus test. Case report.

The authors report a case of pituitary apoplexy resulting in bilateral internal carotid artery occlusion, with marked depression of consciousness and hemiplegia. After transsphenoidal tumor decompression, restoration of flow in both carotid arteries was documented angiographically and the patient made an excellent clinical recovery. The unique aspect of this case is that the pituitary apoplexy was apparently precipitated by neuroendocrine manipulation, performed as a preoperative test of pituitary function.

Adenoma↗
PubMed1984

Thalamic tumors in children. Long-term follow-up and treatment guidelines.

The authors review the cases of 60 children (aged 5 months to 18 years) with thalamic tumors who were seen at The Hospital for Sick Children between 1951 and 1983. The diagnosis of thalamic tumor was based on neuroradiological studies; 33 children were first seen in the pre-computerized tomography (CT) era and 27 since the advent of CT scanning. Histological diagnosis was obtained in 37 patients at the time of operation. A further four tumors were verified histologically at autopsy. Thirty-six patients required cerebrospinal fluid shunt placement. Sixteen patients had no surgery on their tumor, three underwent needle biopsy, 20 underwent open biopsy, and 21 had partial resection. Forty-four patients were irradiated. All 20 patients with malignant tumors died, with a mean survival time of 1.1 years. Of 19 patients with benign tumors, 11 died, with a mean survival time of 5.3 years, and eight are still alive after a mean period of 7.2 years since diagnosis. Based on this series, the authors recommend open biopsy of thalamic tumors (and resection if deemed safe), followed by radiation in selected cases.

Adolescent↗
PubMed1984

Combination therapy with 1,3-bis(2-chloroethyl)-1-nitrosourea and low dose rate radiation in the 9L rat brain tumor and spheroid models: implications for brain tumor brachytherapy.

We studied the effects of combination treatment with 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) and low dose rate radiation in the 9L rat brain tumor in vivo model and the 9L multicellular tumor spheroid model. F-344 rats bearing intracerebral 9L gliosarcomas were implanted with removable 125I sources. Minimal (peripheral) tumor doses of 6387 rad produced an increased life-span (ILS) of 28% over that of control rats implanted with dummy sources, BCNU alone (13.3 mg/kg) produced in an ILS of 67%, and combination treatment with BCNU and implanted 125I sources produced an ILS of 167%. As measured by a colony-forming efficiency assay, the greatest cell kill in 9L spheroids occurred when BCNU was administered 24 hours before irradiation from a 137Cs source at a low dose rate of 5 rad/minute. At a higher dose rate of 210 rad/minute, the time dependence of the effects of combination treatment was identical and therefore independent of dose rate.

Animals↗
PubMed1983

Parental work patterns in alternative families: influence on child development.

The increasing return to work by mothers of young children was documented for matching samples of mothers in families representing traditional marriages, single-mother units, social-contract relationships, and communal living groups. No evidence was found of negative effects on children's social, emotional, and cognitive development attributable to maternal absence due to employment.

Child↗
PubMed1983

Polyol pathway activity and myo-inositol metabolism. A suggested relationship in the pathogenesis of diabetic neuropathy.

Two major metabolic perturbations, increased polyol (sorbitol) pathway activity and reduced tissue myo-inositol content, are induced in peripheral nerve by hyperglycemia. Although they are commonly invoked as alternative biochemical pathogenetic mechanisms for diabetic neuropathy, their possible interrelationship has never been adequately explored. Therefore, we studied the effect of polyol pathway blockade with sorbinil, a specific inhibitor of aldose reductase, on nerve myo-inositol content in acutely streptozotocin-diabetic rats. Sorbinil administration completely prevented the fall in nerve myo-inositol, thereby implicating increased polyol pathway activity as a likely factor in the fall in nerve myo-inositol content in experimental diabetes.

Aldehyde Reductase↗
PubMed1982

Endogenous opioids interact in stress-induced hyperglycemia in mice.

Intermittent inescapable foot shock stress for 1 hour elicited significant hyperglycemia in mice. Pretreatment with the long acting narcotic antagonist naltrexone (1.0 mg/kg, 1 hr prior to stress) prevented stress hyperglycemia. Naltrexone did not affect blood glucose in unstressed control mice. These findings suggest the involvement of endogenous opioids in the hyperglycemic response to stress in mice. The possible mode of interaction of endorphin in stress hyperglycemia is discussed.

Animals↗
PubMed1982

Double-blind food challenge in the diagnosis of food sensitivity in the adult.

This study is an attempt to determine the role of double-blind food challenge (DBFC) in suspected food sensitivity in the adult as compared wih established tests of food allergy, including the skin test, RAST, and leukocyte histamine release (LHR) to specific food antigens. Twenty-two subjects (ages 18 to 67) with histories of reactions to foods were challenged with freeze-dried food or placebo in opaque dye-free capsules, in increasing doses over a 90 min span to a total of 13 to 15 gm. This was repeated twice at weekly intervals by similar DBFC. DBFC was preceded by skin testing and venapuncture for RAST and LHR studies. Patients were kept under observation for 2 hr, after which each was asked to maintain a detailed diary of related symptoms and food ingested over the following week. Of 46 DBFCs, 13 (21%) were positive. The correlation with positive skin tests and positive DBFC was 4/13 (30%). The correlation with positive LHR and positive DBFC was lower at 2/13 (15%), and 1/13 (7.6%) with RAST. We concluded that DBFC is an effective test of adult food sensitivity compared with tests usually performed and should be used when the diagnosis is in doubt.

Adult↗
PubMed1982

Postmortem stability of enzymes detoxifying peroxide in brain.

Glutathione peroxidase, glutathione reductase, and catalase activities were measured to 48 h after death in mouse brains held at temperatures replicating the cooling occurring in human cadaver brain. Glutathione peroxidase was stable for 48 h; catalase was stable for 24 h and then declined 20% in activity. Glutathione reductase was stable for 4 h and then decreased to 55% of its initial activity by 48 h. Perfusion of mouse brain with 0.9% (wt/vol) NaCl did not decrease enzyme activities, indicating that erythrocyte contamination has little effect on measured brain activities. The results suggest that glutathione peroxidase would not be affected by moderate time delays in obtaining human postmortem brains but catalase activity may be affected if brains are not promptly removed. Glutathione reductase is not stable and measurements would require controls carefully matched for postmortem conditions.

Animals↗