Biomedical subjects
Publications and source records attributed to D M Bernstein.
Nuclear scanning appears to be a useful test to screen patients with penetrating injuries to the extremities who have proximity as the only finding suggestive of vascular injury. Patients with abnormal scans should be further studied with standard angiography. Interpretation of the scan is dependent on the reader's experience.
The roles of local wound exploration (LWE) and peritoneal lavage (PL) in the selective management of stab wounds to the lower chest and abdomen were evaluated prospectively in 53 patients. Twenty-four patients underwent immediate laparotomy for obvious clinical signs of intra-abdominal injuries. Twenty-nine patients with evidence of anterior abdominal fascia penetration or equivocal LWE had PL before laparotomy. Operative findings were correlated with the preoperative assessment of LWE and PL. Twenty patients in this group had intra-abdominal injuries. All patients with positive PL were found to have an intra-abdominal injury. Six patients with a negative PL and a positive LWE had visceral injuries. Three of these injuries were considered significant with an overall false negative PL of 15%. Laparotomy performed on the basis of LWE resulted in nine patients (31%) having an unnecessary laparatomy. Careful physical examination, the results of local wound exploration, and peritoneal lavage should be considered in selecting patients with abdominal stab wound for laparotomy.
Variations in inhalation chamber temperature can produce alterations in animal physiology, metabolism of foreign compounds as well as the chemical interaction of pollutant aerosols. This report presents the results of an investigation of the different mechanisms of heat transfer in a 380 L inhalation chamber and discusses the relative effectiveness of various methods that may be used to maintain a uniform chamber temperature during animal exposures. The thermal characteristics of the inhalation chamber were studied using an array of 40 thermocouples, with and without rats in the chamber and with and without 5 cm fiber glass insulation surrounding the chamber. Temperature profiles were measured with different animal loadings and intake air temperatures. An effective heat transfer coefficient of 6.6 +/- 1.8 W/m2 degrees C was determined for the stainless steel walls of the chamber. Heat balance studies with rats in this chamber have shown that with room air intake at a flow rate of 100 L/min, the stainless steel chamber walls were effective at removing approximately ninety percent of the animal heat as compared to the airstream.
A number of studies have shown that glass fibers induce both malignant mesothelioma and fibrosis in rats and that these reactions may be primarily a function of the physical properties of the fiber. However, these studies were carried out with fibers having broad size distributions and used methods of administration which bear little resemblance to the way man is exposed. To better characterize the health effects of glass fibers, techniques have been developed to expose rats to glass fibers of defined sizes by intratracheal instillation of aqueous suspensions and by "nose only" inhalation exposure, and to determine the deposition, translocation, and ultimate fate of these fibers in the rat. The fibers have known size distributions with geometric mean diameters of 1.5 micrometers (sigma g = 1.1) and lengths of either 5 micrometers (sigma g = 1.49) or 60 micrometers (sigma g = 3.76). The fibers have been activated with neutron irradiation. Of the several resulting radionuclides, 65Zn appeared to be the most suitable for long-term clearance studies by use of in vivo whole body radioassay techniques. A fluidized bed aerosol generator has been developed to expose rats by "nose only" inhalation to approximately 500 fibers/cm3. The generator and exposure system permits reuse of fibers which pass through the exposure chamber and produces no significant alteration of the fiber size distribution. Rats were exposed by intratracheal instillations to 20 mg of the longer fibers and to equal numbers (2 mg) and equal mass (20 mg) of the shorter fibers. Through approximately 19 weeks little difference was observed in the whole rat clearance rate of long versus short fibers in the initial exposure group. Histopathology, however, showed differences at this time with the short fibers apparently successfully phagocytized by alveolar macrophages and cleared to the lymph nodes, while the long fibers were not.
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This paper describes construction details and operating characteristics of a nebulizer developed by Sidney Laskin and used over a period of 30 yr in various laboratories to generate respirable aerosols for whole-animal inhalation exposure studies. Under the proper operating conditions, the device is capable of producing nearly monodisperse aerosols in the respirable size range (1.5 micron volume median diameter with a geometric standard deviation of 1.1) for long periods of time
The treatment of a case of catatonic schizophrenia in a renal transplanted patient is presented and demonstrates that electrotherapy can be life-saving and that there are already adequate legal controls which guarantee the patient's rights. Yet zealots are attempting to have legislators pass laws preventing the use of electrotherapy even in voluntary patients. To help prevent these resolutions from being passed, psychiatrists must become more active in the legislative process.
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