Effect of inosine supplementation on 3-mile treadmill run performance and VO2 peak

The purpose of this study was to investigate the ergogenic effect of oral inosine (IN) supplementation (6,000 mg.d-1 for 2 d) upon 3-mile run time (3MTIME) and VO2 peak. Nine highly trained endurance runners participated in a double-blind, placebo (PL), crossover study. Each subject undertook an IN or PL trial, consisting of three exercise tests: a submaximal warm-up run (SUBRUN), a competitive 3-mile treadmill run (3MRUN), and a maximal treadmill run (MAXRUN) to determine VO2 peak and time to exhaustion (MAXTIME). Additional measurements during the 3MRUN and MAXRUN included oxygen uptake (VO2), ventilation (VE), respiratory exchange ratio (R), and ratings of perceived exertion (RPE); blood samples were also taken prior (PRERUN) to the SUBRUN test and following the SUBRUN, 3MRUN, and MAXRUN tests in order to assess glucose, pyruvate, lactate, phosphorus, 2,3-DPG, hemoglobin, and uric acid. Analyses of the data revealed no significant effect of oral IN supplementation either upon 3MTIME (IN = 18.31 +/- 1.21; PL = 18.33 +/- 1.15 min) or VO2 peak (IN = 58.6 +/- 5.1; PL = 60.7 +/- 4.5 ml O2.kg-1.min-1) or upon other dependent variables. MAXTIME was significantly longer during the PL trial (P less than 0.05), suggestive of a possible impairment effect of oral IN supplementation. Based upon our data, we conclude that IN is not an effective ergogenic aid to enhance athletic performance of an aerobic nature.     

Pathways of TRH degradation in rat brain

We have investigated the TRH degradative enzymes in brain by examining the pattern of metabolites formed . The homogenate and three subcellular fractions of rat brain were separately incubated for 1, 5, and 15 minutes with ³H-TRH (pyro-glu-his-³H-proNH₂) at 37°C. TRH and its metabolites were separated on silica gel thin-layer chromatography plates. The crude homogenate and subcellular fractions each produced a characteristic pattern of metabolism. The homogenate metabolized TRH to TRH-OH, proline, and prolineamide. With the P₁ fraction, prolineamide and proline were the major metabolites. In both the homogenate and P₁ fraction incubations, histidyl-prolineamide appeared as a minor component. The P₂ fraction produced prolineamide and histidyl-prolineamide as the major metabolites while the cytosol metabolized TRH primarily to TRH-OH. Proline was formed during incubation with both cytosol and P₂ fractions.The TRH deamidase is found in the soluble fraction of brain tissue homogenate while the pyroglutamate aminopeptidase and the prolineamide cleaving enzyme are associated with particulate fractions. Histidyl-prolineamide is further degraded in the homogenate and P₁ fractions by a secondary metabolic pathway. Proline salvaging enzymes are present in all subcellular fractions of rat brain.     

Stimulation of rat graft-versus-host reactions by polyinosinic-polycytidylic acid.

The effect of polyinosinic-polycytidylic acid (poly I:C) treatment on the rat graft-versus-host reaction (GVHR) initiated in parental to F1 hybrid strain combinations differing at either major or minor histocompatibility determinants were studied in three different protocols. 1 A GVHR initiated in juvenile (LBN)F1 recipients and treated concurrently with poly I:C alone produced neither splenomegaly nor dermatitis in these juvenile rats. (2) Pretreatment of L donors with a single injection of poly I:C 3 days before initiation of the GVHR enhanced resultant splenomegaly in the newborn (LBN)F1 recipients. A high poly I:C dose was inhibitory. (3) Newborn recipients which received lymphocytes from L donors and which were concurrently treated with poly I:C developed dermatitis at an accelerated rate. However, poly I:C alone given to newborns mimicked the GVHR by induction of a syndrome characterized by splenomegaly, dermatitis, thymic involution, and body growth retardation. The parental L and (LF)F1 hybrid strain combination differing only at a minor histocompatibility determinant or in an isogenic hybrid combination (LBN)F1 leads to (LBN)F(1) developed no GVHR when recipients were treated with poly I:C. We conclude that poly I:C can stimulate a rat GVHR initiated with unsensitized donor cells differing at a major histocompatibility locus.     

Conditions for effective Bacillus Calmette-Guérin immunotherapy of postsurgical metastases of 13762A rat mammary adenocarcinoma.

We evaluated critical variables in Bacillus Calmette-Guérin (BCG) immunotherapy of residual 13762A rat mammary adenocarcinoma. BCG was given intratumorally on Day 7 of tumor growth and followed by primary tumor excisions on Day 20. Untreated animals died on about Day 40 with axillary nodal and pulmonary parenchymal metastases. BCG-treated animals experienced prolonged survival, and some were cured. The highest dose (5.0 X 10(7) colony-forming units) of BCG was more effective than the lowest (0.5 X 10(7) colony-forming units), but 1,500 micrograms Corynebacterium parvum were more effective than even the highest BCG dose. Previous sensitization to BCG did not improve the effects of BCG treatment. BCG treatment was effective when given on Day 7 and sometimes as late as Day 12 or 17, but C. parvum was ineffective if given after Day 7. Repeated injections of BCG or C. parvum were not more effective than single injections were. Rats cured of residual 13762A tumor by BCG treatment were strongly and specifically immune to rechallenge. We concluded that a high dose (5.0 X 10(7) colony-forming units) of BCG given early (7 days) was the most effective presurgical treatment of 13762A metastases. Repeated injections or host presensitization to BCG did not improve the benefits.     

Morphometric analysis and identification of infiltrating leucocytes in regressing and progressing Shope rabbit papillomas.

Spontaneous regressions of papillomavirus lesions frequently occur in both human and animal infections. The mechanism by which this occurs is currently unknown. Mononuclear infiltrates are found in regressing human and rabbit papillomas. To assess the potential functional role of these infiltrates in regression, we have characterized and quantitated the cell types present in regressing rabbit lesions. Forty New Zealand white rabbits were inoculated with cottontail rabbit papillomavirus (CRPV) at 2 sites on the dorsal skin. All tumors on 6 rabbits markedly decreased in volume within 6 to 8 weeks of inoculation. Tumors on 4 of these 6 regressor rabbits were studied by immunohistochemistry. Regressor papillomas had conspicuous leucocytic infiltrates, most concentrated at the epithelial basement membrane, and often obliterating the basal cells of the germinal layer. Infiltrating leucocytes were also concentrated in the subjacent dermis immediately beneath the basement membrane. The infiltrates gradually lessened at increased depths in the dermis. In contrast, progressor papillomas contained fewer leucocytes, which were randomly distributed in the dermis. The phenotype of the infiltrating leucocytes was examined in 4 regressing and 12 progressing papillomas. In regressing papillomas, infiltrating leucocytes were predominantly T cells (68.0%), with relatively few B cells (7.4%). Progressing papilloma dermis contained fewer T cells and B cells than regressing papillomas. Most of the infiltrating T cells in regressing papillomas were labelled with a rabbit MHC-class-II-specific monoclonal antibody (MAb) (2C4), in contrast to only a small number in progressing papillomas. In addition to the leucocytic infiltrates, keratinocytes in regressing, but not in progressing, papillomas, frequently exhibited strong 2C4 staining. These results demonstrate that infiltration with T cells expressing rabbit class II is characteristic of regressing Shope papillomas and strengthens the assertion that cell-mediated immunity is the mechanism of Shope papilloma regression.     

Tumorigenicity of simian virus 40-transformed rat hepatocytes

Simian virus 40 (SV40)-transformed F344 rat hepatocytes were transplanted into newborn and normal and irradiated adult syngeneic F344 hosts. Three independently isolated SV40-transformed hepatocyte cell lines were inoculated s.c. into newborn syngeneic animals. One cell line, SV40hpl, produced tumors in two of 12 animals. Fixed tissue sections indicated that the tumors were relatively undifferentiated but had some epithelial cells and contained a peripheral mononuclear leukocyte infiltrate. Serum from a tumor-bearing animal tested by immunoprecipitation demonstrated antibodies to SV40 large-T- but not to small-t-antigen. A portion of one of the tumors was used to prepare the tumor cell line SV40hpl-1, which was 100% positive by immunofluorescence for SV40 nuclear T-antigen. In adult F344 rats subjected previously to whole-body irradiation, inoculation of SV40hpl-1 cells produced tumors in 83% of the animals. Continued passage of the tumor cell line in irradiated rats produced a tumor in one animal which paralyzed its host. The cell line derived from this tumor (SV40hpl-1-T1-2) was tumorigenic in nonirradiated adult hosts. The tumor cell lines were morphologically similar to each other but different from the SV40hpl-transformed cell line; the tumor cells contained less cytoplasm and grew to high densities in strings or multilayered foci without covering the dish surface. All tumor cells retained SV40 antigen expression, and at least one complete copy of the virus genome was retained through two passages in animals. We concluded that SV40 transformation of rat hepatocytes can produce a tumorigenic cell line. We have shown previously that SV40-transformed hepatocytes retain the ability to express proteins characteristic of adult differentiated liver. Development of this model system will enable us to examine expression of these proteins not only in transformed cells with tumorigenic potential but also in tumor tissue and transplantable tumor cell lines.     

Cellular correlates of age-related endocochlear potential reduction in a mouse model

Age-related degeneration of cochlear stria vascularis and resulting reduction in the endocochlear potential (EP) are the hallmark features of strial presbycusis, one of the major forms of presbycusis, or age-related hearing loss (ARHL) (Schuknecht, H.F., 1964. Further observations on the pathology of presbycusis. Archives of Otolaryngology 80, 369–382; Schuknecht, H.F., 1993. Pathology of the Ear. Lea and Febiger, Philadelphia; Schuknecht, H.F., Gacek, M.R., 1993. Cochlear pathology in presbycusis. Annals of Otology, Rhinology and Laryngology 102, 1–16). It is unclear whether there are multiple forms of strial ARHL having different sequences of degenerative events and different risk factors. Human temporal bone studies suggest that the initial pathology usually affects strial marginal cells, then spreads to other strial cell types. While inheritance studies support a moderate genetic influence, no contributing genes have been identified. Establishment of mouse models of strial ARHL may promote the identification of underlying genes and gene/environment interactions. We have found that BALB/cJ mice show significant EP reduction by 19 months of age. The reduction only occurs in a subset of animals. To identify key anatomical correlates of the EP reduction, we compared several cochlear lateral wall metrics in BALBs with those in C57BL/6J (B6) mice, which show little EP reduction for ages up to 26 months. Among the measures obtained, marginal cell density and spiral ligament thickness were the best predictors of both the EP decline in BALBs, and EP stability in B6. Our results indicate that the sequence of strial degeneration in BALBs is like that suggested for humans. Additional strain comparisons we have performed suggest that genes governing strial melanin production do not play a role.     

Effects of rosiglitazone alone and in combination with atorvastatin on the metabolic abnormalities in type 2 diabetes mellitus

This study evaluated the effects of rosiglitazone therapy on lipids and the efficacy and safety of rosiglitazone in combination with atorvastatin in patients with type 2 diabetes mellitus. Three-hundred thirty-two patients entered an 8-week, open-label, run-in treatment phase with rosiglitazone 8 mg/day, and 243 were randomized to a 16-week, double-blinded period of continued rosiglitazone plus placebo, atorvastatin 10 mg/day, or atorvastatin 20 mg/day. With rosiglitazone alone, a modest increase in low-density lipoprotein (LDL) cholesterol (9%), a shift in LDL phenotype from dense to large buoyant subfractions (52% of patients), and an increase in total high-density lipoprotein (HDL) cholesterol levels (6%), predominantly in HDL(2) levels (13%), occurred from week 0 to week 8. When atorvastatin was added, there was a further increase in HDL(3) (5%) and expected significant reductions (p <0.0001) in LDL cholesterol (-39%), apolipoprotein B (-35%), and triglyceride levels (-27%). Glycemic control achieved with rosiglitazone alone was not adversely affected by add-on atorvastatin. The combination was well tolerated compared with placebo. To conclude, in addition to the beneficial effects of rosiglitazone on glycemic control, rosiglitazone and atorvastatin in combination achieved 2 goals: the reduction of LDL cholesterol to <100 mg/dl and the removal of small dense LDL in patients with type 2 diabetes mellitus.