The impact of stress on the clinical presentation of melanoma.

The impact of major life events on the clinical presentation of melanoma was determined in a retrospective case-control analysis. There was a significantly higher occurrence of divorce or marital separation and a significantly higher occurrence of bankruptcy or unemployment in the 5 years prior to the clinical presentation of 56 melanoma patients relative to an age- and sex-matched control group of 56 general surgical patients (p less than 0.01). There was also a higher occurrence of death of a spouse or immediate family member, although this difference was not statistically significant. Overall, 26 (46 percent) of the melanoma patients had major life crises in the 5 years prior to clinical presentation, and this was highly significant (p less than 0.01). We believe that major life stress has an impact on the clinical presentation of melanoma. Potential reasons for this difference are reviewed.

Plasma and tissue alterations of peptide YY and enteroglucagon in rats after colectomy.

Peptide YY (PYY) and enteroglucagon are produced by endocrine cells of the colonic mucosa. PYY inhibits upper gastrointestinal motility, and enteroglucagon is trophic for small bowel mucosa. Adaptive increase in the production and release of these peptides may improve functional results after colorectal resections. We hypothesized that if segments of the colon were resected, then production and release of PYY and enteroglucagon would increase in the remaining segments of bowel. Animals which underwent colonic transections and partial resections had transient elevations of PYY up to 250 +/- 80 pmol/L, which dropped to control group levels in the second week following surgery. Rats with an abdominal colectomy had significantly greater PYY levels than all other groups from the third (208 +/- 30 pmol/L) to the thirty-eighth (100 +/- 16 pmol/L) week of the study. Circulating levels of enteroglucagon were elevated to 156 +/- 35 pmol/L in rats with a right hemicolectomy during the first week following surgery. Enteroglucagon levels did not significantly vary in the other groups studied. Both tissue PYY (413 +/- 33 pmol/gram) and tissue enteroglucagon (171 +/- 17 pmol/gram) were significantly elevated in the rectums of the rats with an abdominal colectomy, as compared to all other groups. The elevated tissue levels may thus account for the ability to maintain elevated plasma PYY. Double immunogold labeling of endocrine cells in the colorectal tissue for PYY and enteroglucagon revealed both peptides within the same endocrine cells and secretory granules. These studies support the hypothesis that circulating levels of PYY are elevated after major colonic resections and suggest that L-type endocrine cells may participate in adaptive responses which improve intestinal function following colonic surgery.

Increasing incidence of cecal and sigmoid carcinoma. Data from the Connecticut Tumor Registry.

We have studied both the distribution and incidence of colorectal cancer using The Connecticut Tumor Registry, the oldest tumor registry in the United States. During the time period 1973 to 1985, left-sided colon cancers accounted for 63% of the cancers, right-sided cancers 33%, and cancers with unspecified sites 4%. Indeed, this pattern of distribution has remained constant for 25 years. For the period 1935 to 1985, we calculated the sex-specific, age-adjusted (normalized to the 1970 U.S. Census) incidence. Age-adjusted incidence of rectal cancer has remained stable for 50 years: for men, 22.8 cases/100,000/year, and for women, 13.9 cases/100,000/year. During these 50 years, the age-adjusted incidence of cecal carcinoma for men has increased from 3.6 to 16.7 cases/100,000/year, while for women, it has increased from 4.9 to 14.2 cases/100,000/year. Sigmoid carcinoma for men has increased from 8.8 to 18.7 cases/100,000/year, and for women, it has increased from 7.7 to 12.8 cases/100,000/year. The incidence of colon cancer at each site has been and continues to be increasing at a constant rate. Age-adjusted incidence for all colorectal cancers has increased from 35.2 to 70.2 cases/100,000/year for men and from 32.1 to 49.2 cases/100,000/year for women. Thus, distribution of colorectal cancers by site in Connecticut has remained stable for 25 years. More importantly, however, the age-adjusted incidence of colon cancer has continued to increase for 50 years, whereas that of rectal cancer has remained relatively stable.

Deoxycholate-stimulated release of peptide YY from the isolated perfused rabbit left colon.

The purpose of this study was 1) to measure the effect of graded concentrations of oleic acid and deoxycholic acid (DCA) on the release of peptide YY (PYY) and enteroglucagon and 2) to test whether DCA-stimulated release of PYY was neurally mediated by blocking neuronal conduction with tetrodotoxin. Studies were performed in isolated left colons from New Zealand White rabbits. Oleic acid in concentrations from 0.22 to 22 mM suspended in 10 mM DCA significantly stimulated release of PYY (P less than 0.01) but resulted in no graded response (Bartlett's test, P = 0.15). Similarly, oleic acid (2.2 mM) suspended with ursodeoxycholic acid (10 mM) produced no increased release of PYY above that achieved by ursodeoxycholic acid alone. In contrast, oleic acid (2.2 and 22 mM suspended with 10 mM DCA) produced a graded release of enteroglucagon during the stimulated period. Deoxycholic acid caused a concentration-dependent release of PYY (1, 3.3, 10, and 25 mM) during the stimulated period. Deoxycholic acid (1 and 10 mM) did not significantly increase enteroglucagon release. Tetrodotoxin blockade had no effect on release of PYY stimulated by 10 mM DCA. Because PYY and enteroglucagon are both found in colonic endocrine cells, these results suggest that the release of PYY and enteroglucagon are mediated by specific secretagogues and not simply caused by noxious effects of the agonists. Also, this study has demonstrated that DCA-stimulated release of PYY is not dependent on neuronally mediated mechanisms.

Characterization of monoclonal antibodies directed against the envelope proteins of feline leukemia virus.

Monoclonal antibodies directed against the feline leukemia virus (FeLV) envelope proteins, gp70 and p15E, were identified by radioimmunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Six of these monoclonal antibodies were specific for the gp70; two for the p15E. Enzyme-linked immunosorbent assay binding assays against FeLV subtypes A, B, and C showed that most of the monoclonal antibodies bound to more than one subtype but have a greater affinity for subtype B. One monoclonal bound exclusively to the FL74 isolate. These studies also indicate that antigenic variability exists between FeLV isolates previously classified as being the same subtype. One antibody was found to bind the gp70s of all FeLV isolates tested and to be directed against a viral neutralizing site. A p15E-specific monoclonal antibody, in addition to binding all the FeLV subtypes, also bound to Moloney and Rauscher murine leukemia viruses, suggesting a group determinant is involved. No binding was seen to human T-cell leukemia virus, bovine leukemia virus, equine infectious anemia virus, or RD114V proteins, however.