Induction of cytochrome CYPIA1 and formation of toxic metabolites of benzo[a]pyrene by rat aorta: a possible role in atherogenesis.

Cigarette smoking is a leading risk factor for atherosclerosis. Endothelial injury may be the initial event in this process. The carcinogenic metabolites of the polycyclic aromatic hydrocarbons found in cigarette smoke tars could cause this injury. We tested this model by examining the effect of 3-methylcholanthrene administration on aortic polycyclic aromatic hydrocarbon metabolism. Immunoblotting with a monoclonal antibody (mAb 1-7-1) specific for cytochromes CYPIA1 and CYPIA2 showed that aortic microsomes from treated, but not from control, animals contained CYPIA1; the CYPIA1 was primarily in the endothelium. Aortic microsomes from induced animals metabolized benzo[a]pyrene (BaP) to the 7R,8S,9,10-tetrahydrotetrol-, 7,8-dihydrodiol-, 1,6 quinone-, 3,6 quinone-, 6,12 quinone-, 3-hydroxy-, and 9-hydroxy-BaP. mAb 1-7-1 inhibited the formation of the tetrahydrotetrol, the dihydrodiol-BaP, and the 3-hydroxy-BaP but did not inhibit the quinones or the 9-hydroxy-BaP. Arachidonic acid did not affect metabolism. These data suggest that the aortas of induced animals metabolize the BaP in cigarette smoke to carcinogenic and toxic products and that this metabolism may initiate vessel injury and lead to the accelerated atherosclerosis seen in cigarette smokers.     

Modulation of mouse mammary tumor growth and linoleate enhanced metastasis by oleate

This study examines whether oleate may influence the linoleate enhanced metastasis of line 4526 murine mammary tumors. In addition, the in vitro proliferative response of line 4526 to oleate and other selected fatty acids was assessed. Initially, the tumor cells were grown in a defined medium supplemented with palmitate, stearate, oleate, linoleate, linolenate or arachidonate. The unsaturated fatty acids stimulated and the saturated fatty acids inhibited proliferation compared to fatty acid-free medium. Next, we examined the effect of oleate on the linoleate enhanced metastasis of 4526 tumors by substituting oleate for saturated fat in isoenergetic diets containing high or low levels of linoleate. Oleate had no effect on metastasis in mice fed the high linoleate diets but it significantly increased metastasis in mice fed the low linoleate diets. Finally, the fatty acid compositions of tumors and mammary fat pads were compared to diet fatty acid compositions and metastatic frequency. Metastasis corresponded more closely to total unsaturated fatty acids than to total polyunsaturated fatty acids or to any individual fatty acid. These studies suggest that both mono- and polyunsaturated fatty acids may stimulate mammary tumor metastasis. However, the influence of dietary oleate probably depends on the level of linoleate and total unsaturated fatty acids in the diet.     

Voices of the Afflicted

Over the past 10 years, I have been privileged to conduct educational forums for audiences containing many recovering alcoholics or otherwise chemically dependent persons. In these forums about the addictive diseases and their treatment and research possibilities, significant interaction with the audience members occurs. During these interactions, certain anecdotal phenomena seem to predominate. The repetitive nature of these reports suggests the need for systematic investigation. As with editorial comments in major medical journals, observed phenomena and unanswered questions from those afflicted can be valuable in the generation of testable hypotheses. Perhaps the ideas presented herein will be useful in the development of future research on alcohol abuse and alcohol dependence.     

Chy-3 mice are Vegfc haploinsufficient and exhibit defective dermal superficial to deep lymphatic transition and dermal lymphatic hypoplasia.

Recent advances in molecular lymphology and lymphatic phenotyping techniques in small animals offer new opportunities to delineate mutant mouse models. Chy-3 mutant mice were originally named for their chylous ascites, but the underlying lymphatic disorder was not defined. We now re-examined these mice and applied advanced genotyping and lymphatic phenotyping techniques to pinpoint the specific lymphatic defect in this mouse model. We demonstrated that Chy-3 mice carry a large chromosomal deletion that includes Vegfc and narrowed this region by monitoring the heterozygosity of genetic markers. We found that Chy-3 mice not only exhibited chylous ascites but also lymphedema of the hind paws and, in approximately half of the males, lymphedema of the penis. Visual lymphangiography and immunofluorescence staining showed a hypoplastic dermal lymphatic network, whereas the blood vasculature appeared unaffected. This hypoplastic lymphatic network was functional, and all adult Chy-3 mice exhibited a lateral lymphatic pathway directly connecting the inguinal to the axillary lymph node. The dermal superficial to deep lymphatic connections in upper limbs and in all cervical regions were intact and functionally drained the upper body. Lymphatic tracer was not transported from the dermal to the deep truncal lymphatic system in the lower limbs, even though the deep lymphatic vessels and nodes were present and patent. These findings further delineate the lymphatic phenotype of Chy-3 mice, identify a collateral lymph drainage pathway previously undescribed in other genetic models of lymphedema, and demonstrate a predilection for lymphatic abnormalities of the lower limbs.     

Lymph node infarction – a rare complication associated with disseminated intra vascular coagulation in a case of dengue fever

Background  

Lymph node infarction is known to occur in association with many non-neoplastic and neoplastic conditions however its occurrence in association with DIC is not reported hitherto in the literature.     

Cross-linking of IgE-receptor complexes at the cell surface: synthesis and characterization of a long bivalent hapten that is capable of triggering mast cells and rat basophilic leukemia cells

The ability of a series of bivalent haptens to bind and cross-link immunoglobulin E (IgE) in solution and on the surface of cells was examined. Several short (less than 30 A) dinitrophenyl (DNP) haptens were found to bind tightly to and cross-link a monoclonal anti-DNP IgE in solution, but these failed to trigger substantial release of 3H-serotonin from sensitized rat basophilic leukemia (RBL) cells or rat peritoneal mast cells. A longer bivalent hapten, approximately 50 A in length, consisting of two DNP-aminocaproyl-L-tyrosine (DCT) groups coupled to the alpha-amino groups of L-cystine was synthesized and characterized. This bivalent hapten [(DCT)2-cystine], binds very tightly to the same monoclonal anti-DNP IgE in solution and cross-links these antibodies to form higher mol. wt aggregates as judged by gel filtration and binding studies. It also stimulates degranulation of both RBL and mast cells sensitized with two different monoclonal anti-DNP IgE antibodies, with the mast cells exhibiting generally greater responsiveness to this ligand. The (DCT)2-cystine bivalent hapten appears to have the structural features necessary for carrying out detailed binding studies with receptor-bound IgE on the cell surface.