Ultrastructural features of diethylnitrosamine-induced lesions in the mouse liver

Mice were given a single dose of diethylnitrosamine (DEN). After 12 and 15 months, the ultrastructural features of simple hepatic nodules and defined hepatocellular carcinomas were compared. The main difference between these two lesions is the presence of highly convoluted membranes in the hepatocytes of the carcinomas. A third population of nodules was also found which could not be easily classified at the light microscope level into either simple hepatic nodules or carcinomas. Ultrastructural examination of these lesions showed them to have areas resembling both simple hepatic nodules and carcinomas. Within both these areas hepatocytes with convoluted plasma membranes were observed. Changes in membrane pattern may be indicative of an altered cell growth pattern and the acquisition of invasive or metastatic properties. This provides further evidence suggesting that a sub-population of cells can be identified which has the potential to develop into overt carcinoma.     

Automated DNA fingerprinting analysis of Mycobacterium tuberculosis using fluorescent detection of PCR products.

DNA fingerprints of Mycobacterium tuberculosis are produced by restriction fragment length polymorphism analysis of the insertion element IS6110. We modified a PCR-based subtyping method, mixed-linker PCR with fluorescent-labeled IS6110-specific oligonucleotides, to demonstrate rapid, automated, and unattended electrophoretic analysis. Variation in band sizing (normally occurring with fragment mobility), an artifact of lane-to-lane and gel-to-gel differences, was controlled with an internal lane standard, resulting in accurate and precise DNA sizing. By using this method, fingerprint analysis can be performed using actual fragment length rather than estimated position analysis.     

Lung injury induced by antibody fragments to angiotensin-converting enzyme.

Rabbits given goat anti-rabbit angiotensin-converting enzyme antibodies or derived antibody fragments develop rapidly fatal pulmonary edema. Endothelial cell injury is manifested by bleb formation and the disintegration of cell membranes. Platelets are found along the injured endothelium and leukocytes block capillary lumens. The pathologic features are similar when immune IgG, F(ab')2, or Fab are given. In vitro studies of complement activation show that solubilized, purified angiotensin-converting enzyme alone activates C1, with consumption of C4 and C3. Addition of immune IgG plus converting enzyme enhances this activation. F(ab')2 plus enzyme enhances only C3 consumption, while Fab with enzyme produces no additional complement utilization. Thus, while complement activation may be involved in the pathogenesis of injury induced by IgG or F(ab')2, the mechanism of Fab-induced endothelial injury remains unclear.     

Heterogeneity of hepatocyte antigen expression in rat liver carcinogenesis: concordance between neoplastic nodules and tumours.

Fischer F344 rats were given a cyclical diet of 0.06% 2-acetylaminofluorene (AAF), which progressively induced oval cell proliferation, cirrhosis and hyperplastic (or neoplastic) nodules. Primary liver tumours developed from 7 months after ceasing the diet. Liver samples taken during and after AAF administration and specimens of primary tumours were processed into frozen sections and examined microscopically for morphological changes in cell populations, stained histochemically for gamma-glutamyl transpeptidase (GGTase) and four phosphatases, and stained by the immunoperoxidase technique for the presence of antigens detected by seven anti-liver cell monoclonal antibodies and monoclonal antibodies to six oncoproteins. During and after AAF treatment several of the anti-liver antibodies revealed foci of aberrantly or heterogeneously-stained cells, although anti-oncoprotein antibodies showed no consistent changes. Foci of cells positive for GGTase and heterogeneous for adenosine triphosphatase (ATPase) were also seen. Nodules invariably showed heterogeneous antigenicity, raised GGTase and abnormal ATPase expression. Primary tumours exhibited varying degrees of positivity, negativity and heterogeneity with the anti-liver monoclonal antibodies, and all were positive for GGTase. Comparison between various parameters and different lesions showed the greatest concordance between nodules and tumours, suggesting that nodules are probably the precursors of malignant tumours in this system.     

Quality control in cervical cytology

From surveys conducted by the authors it is concluded that the best and most acceptable quality control methods in cytology are those from within the laboratory. Most of these have results which can be reported centrally. Where the overall control and codes of practice are high, there the results are the most reliable, as sources of error from whatever cause are quickly brought to light. These conclusions are illustrated by data from the five centres and correlated in the tables.     

Characterization of an SAV organism and proposal of Mycobacterium triplex sp. nov.

Polyphasic taxonomic methods were employed to characterize a new species of slowly growing, nonpigmented mycobacteria. We propose the name Mycobacterium triplex sp. nov. for this new taxon. Conventional identification testing demonstrated a group of similar organisms that were geographically widespread in the United States. Commercially available nucleic-acid probes specific for the Mycobacterium avium complex were unreactive for these strains. High-performance liquid chromatography analysis of the mycolic acids revealed mycolate profiles that closely resembled Mycobacterium simiae. Comparative 16S rRNA sequence data confirmed the phylogenetic relationship of the strains with the slowly growing mycobacteria. Representative-type strains have been deposited in the American Type Culture Collection as strain ATCC 700071 [corrected].     

Behavior in chimeric mice combining differently behaving strains

A/J and C57BL/6J mice behave differently in tests for alcohol preference, open-field activity, defecation in the open field, cricket attacking, and rope climbing. Chimeric mice, i.e., mice containing both A/J cells and C57BL/6J cells, were constructed and tested for these behaviors. Patterns of behavior among A/JC57BL/6J chimeras are such as to suggest that none of these behavior differences is controlled by a single cell or clone and that the same cell population that gives rise to the strain difference in alcohol preference also gives rise to the differences in open-field activity and defecation, while separate cell populations control cricket killing and rope climbing.This research was supported by Research Grants AA 00388 and HD 03015 to M. N. N. and MH 18996 to K. B. Computing assistance was obtained from the Health Sciences Computing Facility, UCLA, supported by NIH Special Research Resources Grant RR-3.     

Mitogenic response of mouse spleen cells and gelation of limulus lysate by lipopolysaccharide of Yersinia pestis and evidence for neutralization of lipopolysaccharide by polymyxin B.

Lipopolysaccharide (LPS) extracted with phenol and water from Yersinia pestis was compared with LPS of Escherichia coli for stimulation of deoxyribonucleic acid synthesis in mouse spleen cells (lymphocyte mitogenesis), gelation of limulus lysate, pyrogenicity in the rabbit, and susceptibility to inhibition of these activities by polymyxin B sulfate (PBS). LPS of Y. pestis stimulated deoxyribonucleic acid synthesis in mouse spleen cell cultures over the same quantitative range as LPS of E. coli. In the limulus tests and rabbit pyrogenicity studies, the LPS of Y. pestis was active but about 10 times less potent than E. coli LPS on a weight basis. PBS in concentrations from 1 to 10 microgram/ml diminished the rate of deoxyribonucleic acid synthesis in spleen cell cultures stimulated by LPS of both Y. pestis and E. coli. Addition of PBS to LPS of both Y. pestis and E. coli in a ratio of 100 parts of PBS to 1 part of LPS by weight increased by 10-fold the concentration of LPS required to produce gelation of limulus lysate and inhibited significantly pyrogenic responses in rabbits. These results demonstrating similarities of LPS of Y. pestis and E. coli may suggest that the pathogenesis of plague is similar to that of other gram-negative bacterial infections.     

Duke Surgery Research Central: an open-source Web application for the improvement of compliance with research regulation

Background  

Although regulatory compliance in academic research is enforced by law to ensure high quality and safety to participants, its implementation is frequently hindered by cost and logistical barriers. In order to decrease these barriers, we have developed a Web-based application, Duke Surgery Research Central (DSRC), to monitor and streamline the regulatory research process.