Experimental enhancement of corticosterone levels positively affects subsequent male survival

Corticosterone is an important hormone of the stress response that regulates physiological processes and modifies animal behavior. While it positively acts on locomotor activity, it may negatively affect reproduction and social activity. This suggests that corticosterone may promote behaviors that increase survival at the cost of reproduction. In this study, we experimentally investigate the link between corticosterone levels and survival in adult common lizards (Lacerta vivipara) by comparing corticosterone-treated with placebo-treated lizards. We experimentally show that corticosterone enhances energy expenditure, daily activity, food intake, and it modifies the behavioral time budget. Enhanced appetite of corticosterone-treated individuals compensated for increased energy expenditure and corticosterone-treated males showed increased survival. This suggests that corticosterone may promote behaviors that reduce stress and it shows that corticosterone per se does not reduce but directly or indirectly increases longer-term survival. This suggests that the production of corticosterone as a response to a stressor may be an adaptive mechanism that even controls survival.

Female common lizards (Lacerta vivipara) do not adjust their sex-biased investment in relation to the adult sex ratio

Sex allocation theory predicts that facultative maternal investment in the rare sex should be favoured by natural selection when breeders experience predictable variation in adult sex ratios (ASRs). We found significant spatial and predictable interannual changes in local ASRs within a natural population of the common lizard where the mean ASR is female-biased, thus validating the key assumptions of adaptive sex ratio models. We tested for facultative maternal investment in the rare sex during and after an experimental perturbation of the ASR by creating populations with female-biased or male-biased ASR. Mothers did not adjust their clutch sex ratio during or after the ASR perturbation, but produced sons with a higher body condition in male-biased populations. However, this differential sex allocation did not result in growth or survival differences in offspring. Our results thus contradict the predictions of adaptive models and challenge the idea that facultative investment in the rare sex might be a mechanism regulating the population sex ratio.

Test-retest reliability of DSC MRI CBV mapping in healthy volunteers

Dynamic susceptibility contrast magnetic resonance imaging (DSC MRI) can be used to generate high resolution maps of cerebral blood volume (CBV). To determine the test-retest reliability, CBV was measured in eight volunteers on two occasions, separated by 4 weeks. The mean ratio (scan 2/scan 1) for 72 cortical regions of interest (ROIs) was 1.03, with a coefficient of variation of 14%. The correlation between the first and second scans was 0.73 (p < 0.0001; 95%). In five hand-drawn ROIs, the mean ratio was 1.08, with a coefficient of variation of 12%. The correlation between scans was 0.84 (p < 0.0001). The data presented here support the hypothesis that DSC MRI CBV mapping has acceptable test-retest reliability.

Personal values and sexual decision-making among virginal and sexually experienced urban adolescent girls

PURPOSE

To guide the development of an intervention to reduce the incidence of sexually transmitted diseases (STDs) in urban, adolescent girls, we investigated such girls' reasons for deciding to have or not to have sexual intercourse.

METHODS

Consecutive girls >or=14 years of age attending an urban adolescent clinic were invited to complete an anonymous survey about sexual decision-making. In this pilot study, girls were asked: (a) whether they agreed with a statement that they had or had not had sexual intercourse "because of my values and beliefs"; and (b) to select from a list one or more specific reasons why they had or had not had intercourse. The girls were categorized by self-report as either "virgins," "currently inactive" (no intercourse in the preceding 3 months), or "currently active" (had intercourse during the preceding 3 months).

RESULTS

Usable surveys were obtained from 197 adolescents whose age (18.2 +/- 2.6 years) and race (69% black) were comparable to those of clinic attendees in general. Forty girls (20%; age 16.1 +/- 2.1 years) were virgins, 25 girls (13%; age 17.8 +/- 2.3 years) were inactive, and 132 girls (67%; age 18.9 +/- 2.5 years) were currently active. "Values and beliefs" were cited as the reason for decisions about sexual behavior by 53% of the virgins, but only by 24% of the sexually inactive and 24% of the sexually active girls (p = .002). Virgins were more likely than inactive girls to cite three specific reasons for not having sex: "not the right thing for me now" (82% vs. 50%, p = .007), "waiting until I am older" (69% vs. 8%, p = .001), and "waiting until I am married" (67% vs. 38%, p = .02). The reason "against my religious beliefs" was cited by 23% of virgins and 13% of inactive girls (p = not significant). Personal values were implicit in the two specific reasons for having sex that active girls chose most frequently, namely, "I like/love the person" (86%) and "I like having sex" (37%), although only 24% of these girls had explicitly cited "values and beliefs" as their reason for having sex.

CONCLUSIONS

Our data indicate that urban girls, both those who have had sexual intercourse and those who have not, view their sexual behavior as being based on personal (although infrequently religious) values. Many of the virginal urban, adolescent girls we surveyed hold abstinence as a personal value. The sexually active adolescents perceive the decision to have sexual intercourse as being based affirmatively on their personal values rather than on the chance occurrence of opportunities to have intercourse. These data may be useful in the development of new strategies for reducing urban adolescent girls' risk of acquiring sexually transmitted diseases.

Rofecoxib, a COX-2 inhibitor, does not inhibit human gastric mucosal prostaglandin production

BACKGROUND & AIMS

Rofecoxib, an inhibitor of the inducible cyclooxygenase (COX)-2 enzyme, appears not to cause acute gastroduodenal injury or chronic ulceration. To attribute this to COX-2 selectivity with sparing of gastric mucosal prostaglandin synthesis requires direct proof.

METHODS

Twenty-four healthy, nonsmoking Helicobacter pylori-negative volunteers were randomized to 1 of 2 separate concurrent blinded crossover studies. Sixteen volunteers received rofecoxib, 50 mg once daily, for 5 days in one treatment period and placebo in the other. Eight volunteers similarly received naproxen, 500 mg twice daily, and placebo. On day 5 of each period, antral mucosal prostaglandin E2 (PGE2) synthesis was measured by radioimmunoassay after vortexing for 3 minutes. Whole blood COX-1 activity was measured as serum thromboxane (TXB)2- and COX-2 activity as lipopolysaccharide (LPS)-induced PGE2.

RESULTS

Naproxen decreased gastric mucosal PGE2 synthesis by 65% (90% confidence interval [CI], 53%-74%; P = 0.001 vs. placebo) in contrast to an 18% increase after rofecoxib (90% CI, -11% to 57%; P = 0.313 vs. placebo). Naproxen also significantly inhibited both serum TXB2 by 94% and LPS-induced PGE2 production by 77% (both P < or = 0.002 vs. placebo), but rofecoxib only inhibited COX-2-dependent LPS-induced PGE(2) (by 79%; P < 0.001 vs. placebo).

CONCLUSIONS

Rofecoxib (50 mg) lacked naproxen's ability to reduce the availability of gastroprotective prostaglandins.

Effects of low-dose alcohol exposure on simulated merchant ship piloting by maritime cadets

The US Department of Transportation (DOT) regulates on-the-job alcohol use by operators of certain categories of commercial transport. For aircraft, trains, and commercial vessels, operators are subject to sanctions for having > or = 0.04 g% blood alcohol concentration (BAC). This study examines the effects of alcohol (between 0.04 and 0.05 g% BAC) on simulated merchant ship handling. A two-group randomized factorial design was used to compare beverage alcohol to placebo while controlling for baseline performance on a previous day. The study was conducted in the Maritime Simulation Center at Maine Maritime Academy, Castine, ME. Participants were 38 volunteer deck officer cadets in their junior or senior year, at least 21 years of age, with previous experience on a bridge simulator. Following a baseline trial on Day 1, on Day 2 participants were randomized to receive alcohol (0.6 g/kg for males and 0.5 g/kg for females) or placebo. After allowing time for absorption, participants completed a bridge simulator task. For baseline and performance trials, participants were randomized to one of four bridge simulator scenarios, each representing passage of a fully loaded container vessel through a channel with commercial traffic. The aggregate scenario score given by blinded maritime educators measured performance. A main effect for alcohol was found indicating that performance was significantly impaired by this low dose of alcohol relative to performance in the placebo condition. These findings are consistent with current federal regulations that limit low-dose alcohol exposure for the operators of commercial transport vehicles. Further research is required to determine effects at lower BACs.

The yeast NuA4 and Drosophila MSL complexes contain homologous subunits important for transcription regulation

In Drosophila, the MSL complex is required for the dosage compensation of X-linked genes in males and contains a histone acetyltransferase, MOF. A point mutation in the MOF acetyl-CoA-binding site results in male-specific lethality. Yeast Esa1p, a MOF homolog, is essential for cell cycle progression and is the catalytic subunit of the NuA4 acetyltransferase complex. Here we report that NuA4 purified from yeast with a point mutation in the acetyl-CoA-binding domain of Esa1p exhibits a strong decrease in histone acetyltransferase activity, yet has no effect on growth. We demonstrate that Eaf3p (Esa1p-associated factor-3 protein), a yeast protein homologous to the Drosophila dosage compensation protein MSL3, is also a stable component of the NuA4 complex. Unlike other subunits of the complex, it is not essential, and the deletion mutant has no growth phenotype. NuA4 purified from the mutant strain has a decreased apparent molecular mass, but retains wild-type levels of histone H4 acetyltransferase activity. The EAF3 deletion and the ESA1 mutation lead to a decrease in PHO5 gene expression; the EAF3 deletion also significantly reduces HIS4 and TRP4 expressions. These results, together with those previously obtained with both the MSL and NuA4 complexes, underscore the importance of targeted histone H4 acetylation for the gene-specific activation of transcription.

A case of giant cell hepatitis recurring after liver transplantation and treated with ribavirin

A patient who underwent orthotopic liver transplantation for giant cell hepatitis with cirrhosis and in whom giant cell hepatitis recurred twice after orthotopic liver transplantation is reported. He was treated with ribavirin with an excellent result. The literature on this subject is reviewed. This observation clearly confirms the efficacy of ribavirin for the treatment of giant cell hepatitis, thus providing evidence for its viral origin.

Aberrant splicing of tau pre-mRNA caused by intronic mutations associated with the inherited dementia frontotemporal dementia with parkinsonism linked to chromosome 17

Frontotemporal dementia accounts for a significant fraction of dementia cases. Frontotemporal dementia with parkinsonism linked to chromosome 17 is associated with either exonic or intronic mutations in the tau gene. This highlights the involvement of aberrant pre-mRNA splicing in the pathogenesis of neurodegenerative disorders. Little is known about the molecular mechanisms of the splicing defects underlying these diseases. To establish a model system for studying the role of pre-mRNA splicing in neurodegenerative diseases, we have constructed a tau minigene that reproduces tau alternative splicing in both cultured cells and in vitro biochemical assays. We demonstrate that mutations in a nonconserved intronic region of the human tau gene lead to increased splicing between exon 10 and exon 11. Systematic biochemical analyses indicate the importance of U1 snRNP and, to a lesser extent, U6 snRNP in differentially recognizing wild-type versus intron mutant tau pre-mRNAs. Gel mobility shift assays with purified U1 snRNP and oligonucleotide-directed RNase H cleavage experiments support the idea that the intronic mutations destabilize a stem-loop structure that sequesters the 5' splice site downstream of exon 10 in tau pre-mRNA, leading to increases in U1 snRNP binding and in splicing between exon 10 and exon 11. Thus, mutations in nonconserved intronic regions that increase rather than decrease alternative splicing can be an important pathogenic mechanism for the development of human diseases.

Effects of low-dose alcohol exposure on simulated merchant ship handling power plant operation by maritime cadets

AIMS

Under current US Department of Transportation (DOT) regulations, some commercial vehicle operators are subject to sanctions for having > or = 00.04 g% blood alcohol concentrations (BACs) on the job. This study investigated the effects of alcohol (between 0.04 and 0.05 g% BAC) on the simulated operation of a commercial ship's power plant.

DESIGN

A balanced placebo design was used in which alcohol administration was fully crossed with expectancy that alcohol was administrated.

SETTING

The study was conducted at the Massachusetts Maritime Academy, Buzzards Bay, MA, USA.

PARTICIPANTS

Participants were 18 volunteer engineering students in their senior year, at least 21 years of age, with previous experience on the diesel simulator.

INTERVENTION

Following a baseline trial on day 1, on day 2 participants were randomized to expectancy (told alcohol or placebo) and beverage (receive alcohol or placebo). The dosage was 0.6 g/kg for males and 0.5 g/kg for females. In both baseline and performance days, participants were randomized to one of four diesel simulator scenarios, each replicating a system failure in a power plant subsystem (e.g. main propulsion, electrical generating).

MEASUREMENT

Performance was measured by time required for problem identification and remediation.

FINDINGS

A main effect for alcohol administration was found. In the alcohol condition, simulator performance time was almost twice as long (351 sec) as on the placebo condition (186 sec). The expectancy effect was not significant.

CONCLUSION

These findings support the current federal policy on the hazards of this low alcohol level within the context of commercial shipping.

Employee drinking practices and work performance

OBJECTIVE

The purpose of this study was to examine the independent effects of a variety of drinking indicators on self-reported work performance.

METHOD

Data from a cross-sectional mailed survey (response rate = 71%) of managers, supervisors and workers (N = 6,540) at 16 worksites were analyzed. Average daily volume was computed from frequency and usual quantity reports. Drinking on the job included drinking during any of six workday situations. The CAGE was used to indicate alcohol dependence. Employees were also asked how frequently they drank to get high or drunk. Work performance was measured through a series of questions about work problems during the prior year. The number of times respondents experienced work performance problems was regressed on the four drinking measures, and a variety of demographic characteristics, job characteristics and life circumstances that might also negatively affect work performance.

RESULTS

The frequency of self-reported work performance problems increased, generally, with all four drinking measures. In a multivariate model that controlled for a number of demographics, job characteristics and life-situations, average daily volume was no longer significantly associated with work performance but the other three drinking measures were. Interestingly, although moderate-heavy and heavy drinkers reported more work performance problems than very light, light, or moderate drinkers, the lower-level-drinking employees, since they were more plentiful, accounted for a larger proportion of work performance problems than did the heavier drinking groups.

CONCLUSIONS

Employers should develop clear policies limiting drinking on the job and, in addition to employee assistance programs for problem drinkers, should develop worksite educational interventions aimed at informing all employees about the relationship between drinking behaviors and work performance.

Did changes in minimum age drinking laws affect adolescent drowning (1970-90)?

OBJECTIVE

To test the hypothesis that changes in the minimum legal drinking age (MLDA) laws would affect drowning among adolescents, the effects of changes in state MLDA laws on drowning were examined for the targeted (18-20 years) and two adjacent (15-17 years and 21-23 years) age groups, over a period of 21 years (1970-90).

METHODS

Poisson maximum likelihood regression was used to estimate the effects of both lowering and increasing the MLDA. The dependent variable in these analyses was the number of drownings per state per year for the age groups observed. At first only state and year effects were controlled for and then any other variable potentially associated with the incidence of drowning was included. The other control variables included proportion of population living near border states with lower MLDA laws, urbanicity, unemployment, divorce, education, poverty, beer tax, and proxy measures for MLDA law enforcement.

RESULTS

No significant association between drowning and MLDA was found for any of the age groups studied.

CONCLUSION

It is concluded that MLDA laws are not an important public policy strategy for affecting drowning rates among adolescents and young adults.

TOM1p, a yeast hect-domain protein which mediates transcriptional regulation through the ADA/SAGA coactivator complexes

The hect-domain has been characterized as a conserved feature of a group of E3 ubiquitin ligases. Here we show that the yeast hect-domain protein TOM1p regulates transcriptional activation through effects on the ADA transcriptional coactivator proteins. Null mutations of tom1 result in similar defects in transcription from ADH2 and HIS3 promoters, and enhanced transcription from the GAL10 promoter as do null mutations in ngg1/ada3. Strains with disruptions of both ngg1 and tom1 have the same phenotype as strains with a disruption of only ngg1 implying that these genes are acting through the same pathway. In the absence of TOM1p, the normal associations of the ADA proteins with SPT3p and the TATA-binding protein are reduced. The action of TOM1p is most likely mediated through ubiquitination since mutation of Cys3235 to Ala, corresponding residues of which are required for thioester bond formation with ubiquitin in other hect-domain proteins, results in similar changes in transcription as the null mutation. A direct role for TOM1p in regulation of ADA-associated proteins is further supported by the finding that SPT7p is ubiquitinated in a TOM1p-dependent fashion and that TOM1p coimmunoprecipitates with the ADA proteins.

Covariates of fear of falling and associated activity curtailment

With a sample survey (N = 266) of elderly adults residing in six housing developments in Massachusetts, we used logistic regression to: (a) identify covariates of fear of falling among all subjects and (b) identify covariates of activity curtailment among the subset of subjects who were afraid of falling. Fifty-five percent of respondents were afraid of falling; of those who were afraid, 56% had curtailed activity due to this fear. Factors associated with fear of falling were: being female, having had previous falls, and having fewer social contacts. Factors associated with activity curtailment among those who were afraid were: not communicating about falls; having less social support; and knowing someone who had fallen. Falls history appears an important contributor to fear of falling, whereas the impact of this fear on activities appears more a function of social support. These findings suggest different strategies for the primary and secondary prevention of fear of falling.

An international validation of the interaction with disabled persons scale

The Interaction with Disabled Persons Scale (IDP) was devised to measure attitudes in terms of discomfort reported about social interaction with people with disabilities. The Scale has been used in Australia for ten years. This article reports results of an international validation project that was designed to determine whether psychometric characteristics and norms emerging for Australian groups apply elsewhere. A methodological proforma was developed to maximize uniformity of data collection across nine countries: Australia, Canada, Croatia, England, Germany, Hong Kong, Poland, Scotland and the United States. In most countries the Scale was administered in English; however it also was translated into Germany, Polish, French and Croat. Results indicate that across countries mean scores fell within ten points, similar moderate to high levels of item homogeneity occurred and level of prior contact with people with disabilities emerged as the strongest predictor of IDP scores. It was concluded that the IDP Scale is a valid measure that is able to discriminate between respondents within the countries included in the study.

Patients' perceptions of outcomes of a Canadian hospitalization

Notes that with health care reform moving at tremendous speed throughout Canada, a great deal of interest in outcomes research has been generated. States that the research team consisted of 17 professional practice leaders from eight disciplines. Proposes, through the research, to identify from the perspective of former patients what results they hoped to achieve prior to discharge from hospital and what facilitated and hindered them in achieving these results. Reports that a representative sample was selected for the study. Forty-one former patients each participated in up to two focus groups, with a total of 16 focus groups conducted. Hierarchical analysis revealed themes that fell within the framework of structure, process and outcomes. The findings will assist in ensuring that more appropriate and effective care is offered to patients by a variety of disciplines.

Determination of the immunization schedule for field trials with the synthetic malaria vaccine SPf 66

The synthetic malaria vaccine SPf 66 has been shown to be safe, immunogenic and effective in trials performed with controlled groups naturally and experimentally exposed to the disease. In order to continue the trials in open populations, it was necessary to standardize the vaccination characteristics. We have performed four field trials with soldier volunteers with the aim, among others, of defining the number of doses required, the intervals between applications, the protein concentration, and the adjuvant to be used. In these trials, the vaccinated individuals' immune responses were evaluated by assaying anti-SPf 66 antibody titres, in vitro growth inhibition of the P. falciparum parasite, and the vaccinees' capacity to recognize P. falciparum native proteins. From these results we conclude that the best vaccination schedule, for adults, is three doses administered subcutaneously on days 0, 30 and 180, each containing 2 mg of the synthetic polymerized petide SPf 66 adsorbed to alum hydroxide.

Occupational asthma: validity of monitoring of peak expiratory flow rates and non-allergic bronchial responsiveness as compared to specific inhalation challenge

The sensitivity and specificity of monitoring peak expiratory flow rates (PEFR) and bronchial responsiveness to the provocative concentration of histamine or methacholine (PC20) has been determined as compared to specific inhalation challenges in the diagnosis of occupational asthma. A prospective study of 61 subjects referred for occupational asthma to various agents was performed. PEFR was assessed every 2 h during a period away from work for at least 2 weeks. The period at work was 2 weeks, or less if there was increased symptomatology or marked changes in PEFR. At least one PC20 assessment was obtained at work and away from work. Graphs of PEFR and PC20 values were interpreted in blind fashion by three experienced readers. There was complete agreement among the three in 54 out of 61 instances (78%). Twenty five out of 61 subjects (41%) had positive specific inhalation challenges. The best index for comparing results of PEFR with specific inhalation challenges was the visual analysis of PEFR with sensitivity and specificity of 81% and 74%. All of the numerical indices were significantly less satisfactory. We conclude that visual analysis of PEFR is an interesting tool for investigating occupational asthma, although sensitivity and specificity values do not seem satisfactory enough to warrant using it alone.

Heat loss from the human head during exercise

Evaporative and convective heat loss from head skin and expired air were measured in four male subjects at rest and during incremental exercise at 5, 15, and 25 degrees C ambient temperature (Ta) to verify whether the head can function as a heat sink for selective brain cooling. The heat losses were measured with an open-circuit method. At rest the heat loss from head skin and expired air decreased with increasing Ta from 69 +/- 5 and 37 +/- 18 (SE) W (5 degrees C) to 44 +/- 25 and 26 +/- 7 W (25 degrees C). At a work load of 150 W the heat loss tended to increase with increasing Ta: 119 +/- 21 (head skin) and 82 +/- 5 W (respiratory tract) at 5 degrees C Ta to 132 +/- 27 and 103 +/- 12 W at 25 degrees C Ta. Heat loss was always higher from the head surface than from the respiratory tract. The heat losses, separately and together (total), were highly correlated to the increasing esophageal temperature at 15 and 25 degrees C Ta. At 5 degrees C Ta on correlation occurred. The results showed that the heat loss from the head was larger than the heat brought to the brain by the arterial blood during hyperthermia, estimated to be 45 W per 1 degree C increase above normal temperature, plus the heat produced by the brain, estimated to be up to 20 W. The total heat to be lost is therefore approximately 65 W during a mild hyperthermia (+1 degrees C) if brain temperature is to remain constant.(ABSTRACT TRUNCATED AT 250 WORDS)

Studies on the humoral immune response to a synthetic vaccine against Plasmodium falciparum malaria

A synthetic vaccine against the asexual blood stages of P. falciparum, the SPf 66 synthetic hybrid polymer, composed of peptides derived from three merozoite membrane proteins as well as one peptide from the sporozoite CS protein, has been developed by our group and tested in different protection assays in Aotus monkeys as well as in human volunteers. This study evaluates the humoral immune response induced by the SPf 66 protein vaccination in adult human volunteers from the Colombian Pacific coast as follows: determination of specific IgG antibody levels against SPf 66 by FAST-ELISA after each immunization; analysis of antibody reactivity with P. falciparum schizont lysates by immunoblots; and determination of the in vitro parasite growth inhibition. A clear boosting effect, dependent on time and dose, was observed in the antibody production kinetics. These antibodies also specifically recognize three proteins of the P. falciparum schizont lysate corresponding to the molecular weights of the proteins from which the amino acid sequence was derived. These sera were also capable of markedly inhibiting in vitro parasite growth.