Progressive effect of endurance training on VO2 kinetics at the onset of submaximal exercise

The rates of increase in O2 uptake (VO2) after step changes in work rate from 25 W to 60% of pretraining peak VO2 (VO2 peak) were measured at various times during an endurance training program (2 h/day at 60% pretraining VO2 peak). Seven untrained males [23 +/- 1 (SE) yr] performed a series of repeated step changes in work rate before training (PRE) and after 4 days (4D), 9 days (9D), and 30 days (30D) of training. VO2 kinetic responses were determined from breath-by-breath data averaged across four repetitions and analyzed using a two-component exponential model. Mean response time (time taken to reach 63% of steady-state VO2) was faster (P < 0.01) than PRE (38.1 +/- 2.6 s) at both 4D (34.9 +/- 2.4 s) and 9D (32.5 +/- 1.8 s) and was faster (P < 0.01) at 30D than at all other times (28.3 +/- 1.0 s). Blood lactate concentrations (after 6 min of cycling) were also lower at 4D and 9D than PRE (P < 0.01) and were lower at 30D than at all other times (P < 0.01). VO2 peak was unchanged from PRE (3.52 +/- 0.20 l/min) at 8D (3.55 +/- 0.20 l/min) but was increased (P < 0.01) at 30D (3.89 +/- 0.18 l/min). Muscle oxidative capacity (maximal citrate synthase activity) was not significantly increased until 30D (P < 0.01). It is concluded that at least part of the acceleration of whole body VO2 kinetics with endurance training is a rapid phenomenon, occurring before changes in VO2 peak and/or muscle oxidative potential.     

Modulation of learning, pain thresholds, and thermoregulation in the rat by preparations of free purified alpha-linolenic and linoleic acids: determination of the optimal omega 3-to-omega 6 ratio

Ingested polyunsaturated fatty acids are postulated to lead to changes in central nervous system activity, presumably by altering the lipid composition of neuronal membranes. In support of this hypothesis, we and other investigators have previously demonstrated cognitive effects in rats fed oils that contain both alpha-linolenic acid (18:3 omega 3) and linoleic acid (18:2 omega 6), with the relative content of alpha-linolenic acid being seen as the critical variable. The present study in rats examined the effects of preparations containing different ratios of highly purified free alpha-linolenic acid to linoleic acid (about 25 mg/kg of body weight daily) on learning performance (Morris water tank), pain thresholds (heated plate), and thermoregulatory control of d-amphetamine-induced hypothermia during 4 weeks of treatment. Preparations with omega 3-to-omega 6 ratios ranging from 1:3.5 to 1:5 (specifically a ratio of 1:4) produced significant favorable effects on all of these variables. Although the specific mode of action remains to be elucidated, these results suggest that such preparations of free fatty acids should be evaluated in the treatment of memory disorders and pain conditions.     

Presynaptic and postsynaptic subcellular localization of substance P receptor immunoreactivity in the neostriatum of the rat and rhesus monkey (Macaca mulatta)

Earlier studies with Arabidopsis thaliana exposed to ultraviolet B (UV-B) and ozone (O3) have indicated the differential responses of superoxide dismutase and glutathione reductase. In this study, we have investigated whether A. thaliana genotype Landsberg erecta and its flavonoid-deficient mutant transparent testa (tt5) is capable of metabolizing UV-B- and O3-induced activated oxygen species by invoking similar antioxidant enzymes. UV-B exposure preferentially enhanced guaiacol-peroxidases, ascorbate peroxidase, and peroxidases specific to coniferyl alcohol and modified the substrate affinity of ascorbate peroxidase. O3 exposure enhanced superoxide dismutase, peroxidases, glutathione reductase, and ascorbate peroxidase to a similar degree and modified the substrate affinity of both glutathione reductase and ascorbate peroxidase. Both UV-B and O3 exposure enhanced similar Cu,Zn-superoxide dismutase isoforms. New isoforms of peroxidases and ascorbate peroxidase were synthesized in tt5 plants irradiated with UV-B. UV-B radiation, in contrast to O3, enhanced the activated oxygen species by increasing membrane-localized NADPH-oxidase activity and decreasing catalase activities. These results collectively suggest that (a) UV-B exposure preferentially induces peroxidase-related enzymes, whereas O3 exposure invokes the enzymes of superoxide dismutase/ascorbate-glutathione cycle, and (b) in contrast to O3, UV-B exposure generated activated oxygen species by increasing NADPH-oxidase activity.     

Interaction of Salmonella typhi strains with cultured human monocyte-derived macrophages

Human monocyte-derived macrophages (MDM) provided this laboratory with a tool to develop a primary-cell assay for evaluating the relative virulence of newly constructed Salmonella typhi carrier strains. In this study, the interaction with and survival within MDM were compared for delta aroA143-attenuated strains, wild-type virulent strains, and the current oral-vaccine strain, Ty21a.     

Evaluation of hepatitis B and C viral markers: clinical significance in Asian and Caucasian patients with hepatocellular carcinoma in the United States of America

In order to evaluate the roles of hepatitis B virus (HBV) and hepatitis C virus (HCV) and their clinical significance in Asian-American and Caucasian patients with hepatocellular carcinoma (HCC) in the USA, 110 HCC patients, seen in a community-based teaching hospital in the Los Angeles area over a 10 year period, were enrolled. Seventy-nine (72%) patients were Asian-American and 31 (28%) were Caucasians. Of the 110 HCC patients, 69 (63%) were positive for serum hepatitis B surface antigen (HBsAg), 26 (24%) were positive for serum antibody to hepatitis C virus (anti-HCV), five (all Asian-Americans) were positive for both markers; 11 (10%) patients had a history of alcoholism. HBsAg was detected in 63 (80%) Asian-American patients, significantly higher than in the six (19%) Caucasian HCC patients (P < 0.01). Anti-HCV was detected in 10 (32%) Caucasian and in 16 (20%) Asian-American HCC patients (P > 0.05). Among Asian-American HCC patients, anti-HCV was more prevalent in those who were HBsAg-negative than in the HBsAg-positive patients (69 vs 8%; P < 0.01). A history of alcoholism was obtained in nine (29%) Caucasian HCC patients, significantly higher than in the two (3%) Asian-American HCC patients (P < 0.05). Comparing HCC patients with positive HBsAg and with anti-HCV, HBsAg-positive HCC patients were younger, Asian-Americans and predominantly male; 38% had a family history of liver disease. In contrast, anti-HCV-positive HCC patients were older by nearly a decade and 46% had a history of blood transfusion. Using a stepwise logistic regression analysis, Asian race and patient age < 50 years were found to be independent predictors for HBsAg-positivity, while a history of blood transfusion was the only predictor for anti-HCV-positivity in HCC patients. There was no significant difference in the rate of cirrhosis, serum levels of alpha-fetoprotein and survival between HBsAg-positive and anti-HCV-positive HCC patients. In conclusion, chronic HBV infection was the major aetiological factor in Asian-American HCC patients, while chronic HCV infection and alcoholism were major aetiological factors in Caucasian HCC patients in the USA.     

Field trial of cyfluthrin as an effective and safe insecticide for control of malaria vectors in triple insecticide resistant areas

Cyfluthrin (Solfac**) 10 wp, a synthetic pyrethroid was evaluated for its efficacy in malaria control through primary health centre approach, and for its acceptance by the community and effect on human health, and non target organisms, in predominantly tribal areas of Maharashtra and Gujarat from 1988 to 1990. Two dosage schedules; 2 rounds of indoor residual sparying a year, at 25 mg/sq. m2 in Maharashtra, and 3 rounds a year at 15 mg/sq. m2, in Gujarat were followed. There was significant reduction in per man hour densities of An. culicifacies the principal malaria vector, and collaterally of C. quinquefasciatus also. Significant reductions in slide positivity rates and slide falciparum rates were observed in both the areas as compared to the controls. The community acceptance of Cyfluthrin in terms of room coverage was 96% in Gujarat, and 89% in Maharashtra, as against average 68.5% and 55% in case of DDT and Malathion respectively. There were no reported ill-effects on humans or non-target organisms.     

Identification of Drosophila cytoskeletal proteins by induction of abnormal cell shape in fission yeast

To clone metazoan genes encoding regulators of cell shape, we have developed a functional assay for proteins that affect the morphology of a simple organism, the fission yeast Schizosaccharomyces pombe. A Drosophila melanogaster cDNA library was constructed in an inducible expression vector and transformed into S. pombe. When expression of the Drosophila sequences was induced, aberrant cell shapes were found in 0.2% of the transformed colonies. Four severe phenotypes representing defects in cytokinesis and/or cell shape maintenance were examined further. Each displayed drastic and specific reorganizations of the actin cytoskeleton. Three of the cDNAs responsible for these defects appear to encode cytoskeletal components: the actin binding proteins profilin and cofilin/actin depolymerizing factor and a membrane-cytoskeleton linker of the ezrin/merlin family. These results demonstrate that a yeast phenotypic screen efficiently identifies conserved genes from more complex organisms and sheds light on their potential in vivo functions.     

The Tarasoff raid: a new extension of the duty to protect

The authors discuss the general outlines of the Tarasoff duty of psychotherapists to protect potential victims of their violent patients. They describe the flexible range of clinical responses that therapists have utilized, as well as their professional concerns about preserving patient confidentiality (or at least strictly circumscribing the scope of disclosure when confidentiality must be breached). A recent case is reported that illustrates a striking new extension of Tarasoff, involving a police search and seizure of a psychotherapist's confidential treatment records and tapes, in response to a third-party complaint that the records contained evidence of his patients' violent acts and propensities. The implications of this case are that the therapist's discretion in the assessment of his duty to protect, the selection of a proper course of action, and the implementation of specific responses may be taken out of his hands, for all intents and purposes, and expropriated by law and order officials. Moreover, regardless of whatever clinical approach he adopts and whether or not he issues a warning, his attempts to preserve patient confidentiality are bound to prove unsuccessful in any future legal proceedings. Patient communications are likely to lose their confidential status on the grounds that they caused or triggered the Tarasoff warning (or that they should have triggered it). If the patient directed serious threats against the therapist himself, the court may find that, as a consequence, a "genuine therapeutic relationship" ceased to exist and thereafter all patient disclosures were no longer confidential on that basis.(ABSTRACT TRUNCATED AT 250 WORDS)