Extent and persistence of streptozotocin-induced DNA damage and cell proliferation in rat kidney as determined by in vivo alkaline elution and BrdUrd labeling assays.

The extent of DNA damage and cellular proliferation induced in rat kidneys by single doses of the diabetogenic alkylating agent streptozotocin (STZ) and the time course of repair of that damage were evaluated using an in vivo alkaline elution assay for DNA strand breaks and a bromodeoxyuridine (BrdUrd) labeling assay for cell replication. Male Sprague-Dawley rats were given iv injections of 0.25 to 60 mg/kg STZ and kidneys were harvested 3 hr later for alkaline elution. A dose of 2.5 mg/kg STZ was the lowest dose to induce detectable DNA strand breaks and extensive damage was produced by the commonly used diabetogenic dose of 60 mg/kg. To characterize the repair of the drug-induced DNA damage, kidneys were harvested from a 60 mg/kg group of animals 3 hr to 27 days after dosing. BrdUrd-labeled kidney sections were also evaluated to assess any cellular proliferative response associated with STZ administration. Significant DNA damage was detected up to 14 days after dosing with return to near background levels by 20 days. Similarly, treatment with 60 mg/kg STZ was associated with increases in BrdUrd labeling indices 4 and 9 days after treatment with resolution by 27 days. These results indicate that the cellular and molecular repair responses to a single diabetogenic dose of STZ are prolonged, requiring up to 3 weeks to complete. Thus, to avoid potential additive or synergistic effects on STZ-induced nephrotoxicity and/or genotoxicity, a delay in the start of experimental therapies in this model (other than insulin) should be considered.

Nocardiosis in liver transplantation: variation in presentation, diagnosis and therapy.

Nocardiosis arose in seven of 191 liver transplant patients (3.7%) over a period of 3.5 years. Four patients had only pulmonary lesions while three had disseminated disease. Nocardia asteroides was isolated from three patients following bronchoscopy, percutaneous aspirate of a pulmonary lesion in one patients, and from the skin from the aspirates in three patients. Delay in diagnosis in two cases was due to negative microscopy; in one, the diagnosis was made only after repeated bronchoscopy. Of the seven patients, three (43%) died. In two of these, nocardiosis was considered to have directly contributed to death. Co-existent bacterial and viral infections were present in all patients who died. In vitro susceptibility of the organism to co-trimoxazole was variable and did not necessarily reflect clinical efficacy. In one patient, a good clinical response was achieved with co-trimoxazole despite apparently reduced in vitro susceptibility.

Evidence of hepatitis A infection in immature rhesus monkeys.

Forty immature (less than 2 years old) rhesus monkeys (Macaca mulatta) with marked increases in aspartate and alanine aminotransferase activities were examined. Serological and histopathological evaluations were done to determine if affected animals were infected with hepatitis A virus. Although no clinical signs of illness were noted in any of the monkeys, an excellent correlation was found between the increased serum aminotransferase values and seropositivity with the acute phase (IgM) HAVAB-M antibody. Histopathological evaluations of livers of selected animals revealed hepatic lesions consistent with those in chimpanzees and marmosets infected with hepatitis A virus: generalized activation of sinusoidal lining cells, focal hepatocellular necrosis with occasional acidophilic bodies, and cuffs of mononuclear cells in the portal areas. Although no animals were seropositive for HAVAB upon receipt from the breeding colony, a total of ten of 18 animals for which serological data were available had seroconverted to HAVAB positivity during the 4-month observation period. These results are consistent with hepatitis A infection in immature rhesus monkeys and indicate the potential significance of serological testing in animals in which hepatic function is being evaluated.

Chronic toxicity/carcinogenesis study of temazepam in mice and rats.

The benzodiazepine temazepam was given to Charles River CD rats for 2 years in the diet at dosages of 10, 40, and 160 mg/kg day. An 18-month study was performed in Charles River CD-1 mice via dietary admixture at dosages of 10, 80, and 160 mg/kg/day. Mean body weights were significantly decreased for high dose rats of both sexes from Treatment Week 39 until termination. All drug treated male groups had a higher rate of mortality when compared to the male control groups, primarily due to deaths occurring between 19 to 24 months. Compound-related hepatic lipidosis accompanied by an increase in liver weights was observed at the high dose level in the 6- and 12-month and terminal sacrifices, as well as the middle dose level at the 12-month interim sacrifice. No evidence was found of compound induced carcinogenicity at any time period. Mortality for male mice was significantly higher in the two higher dose groups; this resulted from bite wounds associated with a drug-related increase in fighting behavior. An isolated finding of borderline statistical significance (p = 0.0556) was noted for hepatocellular adenomas in high dose female mice (4/100) at the 18-month terminal sacrifice. This incidence is well within the reported historical control range (0-14%). Minimal hepatoproliferative (hyperplastic nodules) and vascular effects (telangiectasis) were seen in the high dose male and female mice at the 18-month terminal sacrifice. Thus, these results were similar to those previously reported for oxazepam although meaningful effects on neoplasia did not occur with temazepam. Unlike in man, temazepam is primarily metabolized to oxazepam in the mouse and thus these results are not adverse with regard to human safety evaluation.

Marked anterior displacement of the trachea and larynx from an esophageal obturator airway (EOA).

A 67-year-old man suffering cardiopulmonary arrest had an apparently uneventful placement of an esophageal obturator airway (EOA) by a well-trained ambulance crew. Subsequent clinical evaluation showed ventilation to be marginal. Attempts to insert an endotracheal tube were unsuccessful because the larynx could not be visualized. A subsequent postmortem examination showed that the EOA tube was kinked and bent back on itself so that the distal (balloon) end lay underneath the larynx, displacing it anteriorly.

Spontaneous tumors in control F344 and charles river-CD rats and Charles River CD-1 and B6C3HF1 mice.

The incidence of spontaneous neoplasms in outbred, inbred and F1 hybrid strains was compared using the Charles River-CD rat and mouse, the F344 rat, and B6C3HF1 mouse. These strains are commonly used in carcinogenic studies. Each strain has a consistent pattern of tumor occurrence; testicular, pituitary and lymphoreticular neoplasms are common in F344 rats, mammary and pituitary neoplasms are common in Charles River-CD rats, liver neoplasms are uncommon in CD-1 mice, while hepatic tumors are frequent in male B6C3HF1 mice. There is considerable variation in tumor incidence in individual studies regardless of strain and there appeared to be greater variation in incidence between laboratories using the same strain than in the different laboratories using unlike strains. Therefore, the choice between these strains may be fortuitous or recommended by governmental agencies. Regardless of the strain selected, it is vital to develop sufficient historical tumor data on the strain used at the particular test laboratory.

Varied manifestations of a familial lymphoproliferative disorder.

In a sibship of nine adults, four died of lymphocytic or histiocytic lymphomas, and one of Waldenström's macroglobulinemia (immunoglobulin M [IgM], kappa type) complicated by adenocarcinoma of the lung. In the next generation, one member died of Hodgkin's disease; four of nine healthy persons had impaired lymphocyte transformation in vitro in response to phytohemagglutinin-P (PHA-P), and three of these had polyclonal elevations in IgM levels. Subsequent to these observations, adenocarcinoma of the lung developed in one woman with immune defects, and lymphocytic leukemia developed in her 3 year old grandson. The findings in this family point to a genetically regulated defect of immunity expressed as diverse lymphoproliferative disorders, including polyclonal and monoclonal IgM gammopathies. The occurrence of pulmonary adenocarcinoma in two members suggests genetic and immunologic determinants in these instances.