Peroxidase-catalyzed oxidation of chlorophenols to polychlorinated dibenzo-p-dioxins and dibenzofurans.

Chlorophenols are transformed in vitro to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) by peroxidase-catalyzed oxidations. This is demonstrated with bovine lactoperoxidase as well as horseradish peroxidase, and with 3,4,5- and 2,4,5-trichlorophenol (TrCP). The yield of total PCDD/Fs with lactoperoxidase was 11 micrograms per g 345-TrCP and 10 micrograms per g 245-TrCP, of which 2,3,7,8-substituted PCDD/Fs constituted 8.5 and 2.2 micrograms/g, respectively, corresponding to 0.85 and 1.2 micrograms/g of Nordic TCDD-equivalents.

Massive hemorrhage into intracranial neurinomas.

Massive bleeding into an intracranial neurinoma is a rare event. The 12th case of this particular occurrence, which was precipitated by weight lifting, is described and a review of the literature is presented. Risk factors for bleeding appear to be tumor size and vascularity. Presenting symptomatology is abrupt and includes headache, nausea, vomiting, and depressed consciousness. Preexisting symptoms referrable to and marked dysfunction of the cranial nerve of origin are present. Deficits of neighboring cranial nerves are frequent. Computed tomography demonstrates the hemorrhages and the tumors. Mild head injury and physical exertion were precipitating factors in two cases. One-fourth of the patients died, while the others made good recoveries.

Symptomatic Rathke's cleft cyst with pituitary adenoma: case report.

A rare case of a pituitary adenoma found in association with a symptomatic Rathke's cleft cyst in a 34-year-old women presenting with headaches, visual symptoms, and amenorrhea is described. The diagnostic evaluation and operative treatment of these coincident lesions are discussed.

Flow-regulated continuous spinal drainage: technical note with case report.

A new method for continuous external drainage of cerebrospinal fluid (CSF) for the treatment of CSF fistulas is described. In this system, CSF is withdrawn continuously from the lumbar subarachnoid space at a controlled flow rate calculated to be slightly less than the natural absorption rate of CSF. Controlled spinal drainage can be achieved using equipment readily available in most intensive care units. This system was developed to prevent pneumocephalus during CSF drainage, as illustrated in the case presentation.

Monitoring exposure of personnel to volatile nitrosamines in the laboratory environment.

A convenient sampling method was developed for collection of volatile nitrosamines from large-volume air samples. Stainless steel tubes containing 0.3 g Tenax GC were employed to collect nitrosamines from 5-30 1 air samples. Nitrosamines were eluted from the sample tubes with diethylether to minimize formation of artifacts which were observed when thermal desorption was employed. Eluates were analysed directly by GC-TEA and nitrosamine identities were confirmed using high-resolution GC-MS with selected ion-monitoring. The detection limit was approximately 0.8 micrograms/m3 (0.3 ppb) for NDMA in 2 ml of diethylether extract. The laboratory operations studied included chemical synthesis, trace analysis, animal treatment, microbial mutagenesis tests and in vitro biochemical procedures. In most cases, nitrosamines were not detected in laboratory air, but levels of 200-800 micrograms/m3 (42 to 180 ppb) of N-nitrosomethyl-tert-butylamine were measured during animal treatment, 0.8-8.6 micrograms/m3 (0.3 to 2.8 ppb) of NDMA during mutagenesis assays, 12-22 micrograms/m3 (4-7 ppb) of NDMA during in vitro metabolism studies and 11 micrograms/m3 (3.6 ppb) of NDMA in a walk-in refrigerator. Appropriate corrective measures reduced all nitrosamine levels to below the detection limit. Hamsters and rats treated with NDAA (80 mg/kg, s.c.) excreted 4.4 and 12.9%, respectively, of the nitrosamine in expired air in 24 hr. This route of excretion may be metabolically significant and should be considered in the safe design of animal treatment and holding facilities.

Relative merits of partial splenectomy, splenic reimplantation, and immunization in preventing postsplenectomy infection.

Partial splenectomy, splenic autotransplantation, and immunization with pneumococcal vaccine have been reported to protect patients against overwhelming postsplenectomy infection, and this study was undertaken to evaluate these therapeutic alternatives. For this purpose 136 rats were divided into experimental groups: 34 controls, 34 splenectomy, 34 partial splenectomy, and 34 splenic autotransplantation animals. Five weeks after operation, two-thirds of the animals were immunized with killed pneumococci. The effects of operation and immunization were studied by challenging the animals intravenously with pneumococci. Pneumococcal antibody titers were determined, and phagocytic uptake of pneumococci by the spleen and liver was measured. Immunization impressively increased the survival rate in all groups. At low-challenge doses autotransplantation prolonged survival. At higher-challenge doses only partial splenectomy increased survival. Partial splenectomy and control animals had higher antibody titers than did splenectomy and autotransplantation rats. Animals with the highest antibody titers had the greatest splenic and hepatic phagocytic uptake of pneumococci. Partial splenectomy was more efficient in removing pneumococci than was autotransplantation. Thus immunization is one of the most important factors contributing to survival after splenectomy. Partial splenectomy is preferable to splenic autotransplantation because it is associated with higher antibody titers after immunization, better pneumococcal splenic uptake, and improved survival rates.

Heterotopic splenic autotransplantation in prevention of overwhelming postsplenectomy infection.

An experimental study was undertaken to evaluate the protective effect of heterotopic splenic autotransplantation in weanling rats. Rats were divided into three experimental groups: splenectomy, control, and splenic autotransplantation. Rats were challenged with i.v. type I pneumococcus. Bacterial bloodstream clearance and survival were determined. Splenic bacterial uptake was measured by determining the isotopic activity of technetium-99m-labeled pneumococci. Autoradiographs and material stained with hematoxylin and eosin and Gram strains were examined for histologic features. All autografts survived and were histologically compatible with normal splenic tissue. Bloodstream clearance of pneumococci was significantly greater in rats with splenic autotransplantation. Splenic autografts had 10 to 30 times greater uptake of pneumocci than did the liver. Rats with autotransplantation had a prolonged survival time. Heterotopic splenic autotransplantation may prove to be an important adjunctive surgical measure in the treatment of children undergoing splenectomy.