Negative perceptions about condom use in a clinic population: comparisons by gender, race and age

We sought to elucidate the associations of 13 items assessing negative perceptions about condom use with gender, age and race in a sample of clinic attendees. Patients from four clinics, in three US cities, were recruited (N = 928). Data were collected using audio-computer-assisted self-interviewing. The primary measure was a 13-item adapted version of the Condom Barriers Scale. Logistic regression and chi-square tests were employed to relate the 13 items to gender, age and race. Gender, race and age all had significant associations with negative perceptions of condoms and their use. A primary finding was a large number of significant differences between men and women, with negative perceptions more common among women than among men. For African Americans, especially women, negative perceptions were more common among older participants than among younger participants. In conclusion, important demographic differences regarding negative perceptions may inform the tailoring of intervention efforts that seek to rectify negative perceptions about condoms and thus promote condom use among individuals at risk for sexually transmitted infections (STIs) in the USA. On the other hand, our findings also suggest that the majority of STI clinic attendees may hold positive perceptions about condoms and their use; maintaining and building upon these positive perceptions via education, counselling, and access is also important.

A comparison of condom use errors and problems for heterosexual anal and vaginal intercourse

Condom use errors and problems were compared for anal and vaginal intercourse among a convenience sample of heterosexual men aged 18-66 years (n = 757). Men completed an online questionnaire for the last male condom use event for penile-anal (10.4%) or penile-vaginal (89.6%) intercourse. The prevalence of condom use errors and problems was similar regardless of intercourse type with a few exceptions; those reporting anal intercourse were significantly more likely to report using water-based (P < 0.001) and oil-based (P = 0.037) lubricant and to remove condoms before sex was finished (P < 0.001). The large majority of the sample (93.8%) reported at least one of the nine errors assessed and almost half (46.2%) reported at least one of the seven problems, indicating that many adults may need assistance with these issues. Condom use promotion programmes designed for heterosexual adults are needed that address condom use errors and problems for penile-anal as well as penile-vaginal intercourse.

Men with broken condoms: who and why?

OBJECTIVES

To identify (1) the prevalence of condom breakage, and demographic and sexuality-related differences among young men who have sex with women reporting and not reporting this event; (2) condom-specific behaviours associated with breakage.

METHODS

Young men (n = 278) attending a clinic for treatment of sexually transmitted infections (STIs) responded to an anonymous questionnaire aided by a CD recording of the questions. The samples were screened to include only men who had used a condom during penile-vaginal sex at least three times in the past 3 months. Condom-specific behaviours (including breakage) were assessed using these last three acts of condom use as the recall period. Correlates achieving bivariate significance were subjected to multivariate analysis.

RESULTS

Nearly one third (31.3%) of the men reported recent breakage. The breakage rate was 15%. Three correlates significantly distinguished between men who did and did not report breakage. Men who had past STIs were more likely to report breakage (adjusted odds ratio (AOR) 2.08), as were men who also reported condom slippage (AOR 2.72). Less self-efficacy for correct condom use was also significantly associated with breakage (AOR 1.07). Further, three condom-specific behaviours were significantly associated with breakage: allowing condoms to contact sharp objects (AOR 2.6), experiencing problems with the "fit or feel" of condoms (AOR 2.3) and not squeezing air from the receptacle tip (AOR 2.0).

CONCLUSIONS

Breakage may be common and may occur in a larger context of difficulties with condoms. STI clinics could potentially benefit some men by providing instructions on the correct use of condoms.

Molecular epidemiology of enterovirus 71 over two decades in an Australian urban community

Enterovirus 71 (EV71), first isolated in 1969, has been responsible for numerous outbreaks of hand, foot and mouth disease (HFMD) with a small proportion of cases associated with neurological disease. Since 1997 there has been a significant increase in both the prevalence and virulence of EV71 in the Asia-Pacific region. We have examined the genetic diversity of EV71 in a large Australian city (Sydney N.S.W.) over a nineteen-year period. We determined the VP1 gene sequence of forty-eight EV71 strains isolated between 1983 and 2001. Analysis by molecular phylogeny revealed the presence of four subgenogroups B2, B4, C1 and C2. The results indicate that the major lineage circulating in Sydney N.S.W. was subgenogroup C1 with a recent switch in dominance to B4 in 2000 and 2001.

Assessment of condom use in men and women

Self-reported condom use is a key variable in surveys of sexual behavior and in studies evaluating interventions to reduce the risk of sexually transmitted infections. This article provides a review of how male condom use has been assessed in research. We critically review a number of methodological issues, including the length of the recall period, terminology, specification of partner variables, validity and reliability of condom use, and use of newer data collection methods such as daily diaries and computer-assisted and online technologies. Assessment of condom use errors and problems, and the role of women in condom use are discussed. Finally, we offer recommendations for improving assessment of condom use in future research.

If the condom fits, wear it: a qualitative study of young African-American men

OBJECTIVE

To extend the current knowledge base pertaining to condom failure among young African-American men by assessing their experiences with male condom use.

METHODS

Qualitative assessments were conducted with 19 African-American men (aged 18-29 years) who had just been diagnosed with an STI and reported using condoms in the previous 3 months.

RESULTS

Five categories were identified from the data. These categories pertained to: (1) the "fit and feel" of condoms; (2) condom brand and size; (3) application problems; (4) availability of condoms and lubricants; and (5) commitment to condom use. Common themes included reasons why men believed condoms would break or slip off during sex. Comfort problems, including tightly fitting condoms and condoms drying out during intercourse, were mentioned frequently. Condom associated erection problems were often described. Many men also noted that condom use reduced the level of sexual satisfaction for their female partners. Men noted that finding the right kind of condom was not always easy and it became apparent during the interviews that men typically did not acquire lubrication to add to condoms. Despite their expressed problems with using condoms, men were, none the less, typically emphatic that condom use is an important part of their protective behaviour against STIs.

CONCLUSION

Men were highly motivated to use condoms; however, they experienced a broad range of problems with condom use. With the exception of losing the sensation of skin to skin contact, the vast majority of these problems may be amenable to behavioural interventions.

Better psychological functioning and higher social status may largely explain the apparent health benefits of wine: a study of wine and beer drinking in young Danish adults

BACKGROUND

Findings from a recent series of Danish studies suggest that moderate wine drinkers are healthier than those who drink other alcoholic beverages or those who abstain.

OBJECTIVE

To identify possible explanatory factors associated with the health benefits of wine consumption through the examination of a wide spectrum of social, cognitive, and personality characteristics related to both beverage choice and health in young Danish adults.

SUBJECTS AND METHODS

Descriptive cross-sectional study of characteristics associated with beverage choice in a sample of 363 men and 330 women between the ages of 29 and 34 years, selected from the Copenhagen Perinatal Cohort on the basis of perinatal records.

MAIN OUTCOME MEASURES

Socioeconomic status, education, IQ, personality, psychiatric symptoms, and health-related behaviors, including alcohol consumption, were analyzed. The outcome variables were subjected to linear and logistic regression analyses with 2 factors (beer and wine), each with 2 levels (drinking or not drinking a certain beverage type).

RESULTS

Wine drinking was significantly associated with higher IQ, higher parental educational level, and higher socioeconomic status. Beer drinking was significantly associated with lower scores on the same variables. On scales concerning personality, psychiatric symptoms, and health-related behaviors, wine drinking was associated with optimal functioning and beer drinking with suboptimal functioning.

CONCLUSIONS

Our data demonstrate that wine drinking is a general indicator of optimal social, cognitive, and personality development in Denmark. Similar social, cognitive, and personality factors have also been associated with better health in many populations. Consequently, the association between drinking habits and social and psychological characteristics, in large part, may explain the apparent health benefits of wine.

A prospective study of the effects of oral contraceptives on sexuality and well-being and their relationship to discontinuation

The purpose of the study was to explore predictors of discontinuation of oral contraceptives (OC) including pre-OC use characteristics and adverse physical, emotional, and sexual effects of OCs. Women aged 18+ years in committed, sexually active relationships were assessed before starting OC and reassessed at 3, 6, and 12 months or shortly after discontinuation. Assessment included pre-OC use attitudes and expectations about the pill; self-reported side effects and perimenstrual symptoms including premenstrual syndrome (PMS); physical and emotional well-being; and sexual interest, enjoyment, and frequency of sexual activity. Seventy-nine women completed the study, 38% continued OCs, 47% discontinued, and 14% switched to another OC. Emotional side effects, worsening of PMS, decreased frequency of sexual thoughts, and decreased psychosexual arousability correctly categorized 87% of cases by using logistic regression. Emotional and sexual side effects were the best predictors of discontinuation/switching, yet such OC effects have been largely ignored in the research literature.

Effects of fragrance on female sexual arousal and mood across the menstrual cycle

The effects of fragrance on sexual response in women were investigated using subjective and physiological measures of sexual arousal and of mood. Responses were obtained from female participants in three different fragrance conditions (female fragrance, male fragrance, and a "blank" or neutral substance), as they viewed erotic and sexually neutral films, and fantasized about sexual situations. Each woman was tested twice: during the midfollicular and periovulatory phases of her menstrual cycle. Menstrual cycle phase effects were apparent; self-report data indicated greater sexual arousal and more positive mood during the periovulatory than during the follicular phase. Results demonstrated a positive effect of the male fragrance on genital arousal during erotic fantasy, but this finding was apparent only during the follicular phase testing session. This effect did not appear to be mediated by any effects of fragrance on mood.

Reduced cadherin/catenin complex expression in celiac disease can be reproduced in vitro by cytokine stimulation

Celiac disease is characterized by a chronic immune response to dietary gluten, in which T cell responses result in elevated mucosal levels of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1, interferon (IFN)-gamma, and transforming growth factor (TGF)-beta, which induce profound mucosal remodeling associated with increased enterocyte proliferation, apoptosis, and migration. Reduced intestinal expression of the morphoregulatory cell adhesion molecule E-cadherin, which forms complexes with beta-catenin, can increase enterocyte proliferation and migration. However, its mechanism of action in gastrointestinal inflammatory conditions and any involvement in celiac disease is unknown. In this study, we describe changes in E-cadherin and beta-catenin expression in celiac disease tissue and determine the effect of cytokines on their expression in an in vitro model. We assessed E-cadherin and beta-catenin expression in intestinal biopsies from 24 patients with celiac disease, 12 patients with treated celiac disease, and 10 healthy patients by immunohistochemistry, Western blotting, and confocal microscopy. Using Caco-2 cells, we examined the effect of TNF-alpha, IL-1, IFN-gamma, and TGF-beta on E-cadherin expression. E-cadherin transcription was assessed in both intestinal biopsies and Caco-2 cells by in situ hybridization and RT-PCR, respectively. A marked reduction in protein expression of E-cadherin and beta-catenin that returns to normal levels after treatment was observed in celiac disease; this reduction was associated with reduced levels of E-cadherin mRNA. E-cadherin expression in Caco-2 cells was significantly reduced after TNF-alpha, IL-1, and IFN-gamma stimulation. The effect of TNF-alpha on E-cadherin expression was maximal after stimulation for 48 hours and also induced modest reductions in beta-catenin expression. The action of TNF-alpha on E-cadherin was reversible and was shown to act at the transcriptional level. These results demonstrate the novel findings that E-cadherin and beta-catenin expression are reversibly down-regulated in celiac disease and that such changes in epithelial cadherin/catenin complexes may be mediated by cytokines acting on cadherin transcription.

The roles of two amino acid residues in the active site of L-lactate monooxygenase. Mutation of arginine 187 to methionine and histidine 240 to glutamine

Lactate monooxygenase (LMO) catalyzes the conversion of L-lactate to acetate, CO(2), and water with the incorporation of molecular oxygen. Arginine 187 of LMO is highly conserved within the family of L-alpha-hydroxyacid oxidizing enzymes (Lê, K. H. D., and Lederer, F. (1991) J. Biol. Chem. 266, 20877-20881). By comparison with the equivalent residue in flavocytochrome b(2) from Saccharomyces cerevisiae (Pike, A. D., Chapman, S. K, Manson, F. D. C,. Reid, G. A. , Gondry, M., and Lederer, F. (1996) in Flavins and Flavoproteins (Stevenson, K. J., Massey, V., and Williams, C. H., Jr., eds) pp. 571-574, University of Calgary Press, Calgary, AB, Canada), arginine 187 might be expected to have an important role in catalytic efficiency and substrate binding in LMO. Histidine 240 is predicted to be close to the substrate binding site of LMO, although it is not conserved within the enzyme family. Arginine 187 has been replaced with methionine (R187M), and histidine 240 has been replaced with glutamine (H240Q). L-Lactate oxidation by R187M is very slow. The binding of L-lactate to the mutant enzyme appears to be very weak, as is the binding of oxalate, a transition state analogue. The binding of pyruvate to the reduced enzyme is also very weak, resulting in complete uncoupling of enzyme turnover, with H(2)O(2) and pyruvate as the final products. In addition, anionic forms of the flavin are unstable. The K(d) for sulfite is increased nearly 400-fold by this mutation. The semiquinone form of R187M is also thermodynamically unstable, although the overall midpoint potential for the two-electron reduction of R187M is only 34 mV lower than for the wild-type enzyme. H240Q more closely resembles the wild-type enzyme. The steady-state activity of H240Q is completely coupled. The k(cat) is similar to that for the wild-type enzyme.

Role of the flavin midpoint potential and NAD binding in determining NAD versus oxygen reactivity of xanthine oxidoreductase

Xanthine oxidoreductase from bovine milk can be prepared in two interconvertible forms, xanthine oxidase (XO) and xanthine dehydrogenase (XDH), depending on the number of protein cysteines versus cystines. Enzyme forms differ in respect to their oxidizing substrates; XDH prefers NAD to molecular oxygen, whereas XO only reacts significantly with oxygen. The preference for oxidizing substrate is partially explained by thermodynamics. Unlike XDH, the midpoint potential of the FAD, the center at which oxygen and NAD react, is too high in XO to efficiently reduce NAD (Hunt, J., Massey, V., Dunham, W.R., and Sands, R.H. (1993) J. Biol. Chem. 268, 18685-18691). To distinguish between changes in thermodynamics and in substrate binding, samples of both XO and XDH have been prepared in which the native FAD has been replaced with an FAD analog of different redox potential, 1-deaza-FAD or 8-CN-FAD. Reductive titrations indicate that both 1-deaza-XO and 1-deaza-XDH have a flavin midpoint potential similar to native XDH and that 8-CN-XO and 8-CN-XDH each have a flavin potential higher than XO. Both the low potential 1-deaza-XO and the high potential 8-CN-XDH contain essentially no xanthine/NAD activity. However, 1-deaza-XDH does exhibit xanthine/NAD activity, and 8-CN-XO has normal xanthine/oxygen activity. The binding of NAD to oxidized XO and XDH was investigated by ultrafiltration and isothermal titration calorimetry. The Kd for the binding of NAD to XDH was determined to be 280 +/- 145 microM by ultrafiltration and 160 +/- 40 microM by isothermal titration calorimetry. No evidence for the binding of NAD to XO by either method could be obtained. A low flavin midpoint potential is necessary but not sufficient for dehydrogenase activity.

Would you say you "had sex" if...?

CONTEXT

The current public debate regarding whether oral sex constitutes having "had sex" or sexual relations has reflected a lack of empirical data on how Americans as a population define these terms.

OBJECTIVE

To determine which interactions individuals would consider as having "had sex."

METHODS

A question was included in a survey conducted in 1991 that explored sexual behaviors and attitudes among a random stratified sample of 599 students representative of the undergraduate population of a state university in the Midwest.

PARTICIPANTS

The participants originated from 29 states, including all 4 US Census Bureau geographic regions. Approximately 79% classified themselves as politically moderate to conservative.

MAIN OUTCOME MEASURE

Percentage of respondents who believed the interaction described constituted having "had sex."

RESULTS

Individual attitudes varied regarding behaviors defined as having "had sex": 59% (95% confidence interval, 54%-63%) of respondents indicated that oral-genital contact did not constitute having "had sex" with a partner. Nineteen percent responded similarly regarding penile-anal intercourse.

CONCLUSIONS

The findings support the view that Americans hold widely divergent opinions about what behaviors do and do not constitute having "had sex."

The thermodynamics of xanthine oxidoreductase catalysis

Xanthine oxidoreductase is a complex enzyme found in a wide range of organisms. Recent interest in this enzyme stems from its ability to produce reactive oxygen species under a range of conditions. It is found as a homodimer, each unit containing a molybdopterin cofactor, two iron sulfur centers, and FAD. The enzyme can exist in two forms that differ primarily in their oxidizing substrate specificity. The dehydrogenase form preferentially utilizes NAD+ as an electron acceptor but is able to donate electrons to molecular oxygen. Xanthine dehydrogenase from mammalian sources can be converted to an oxidase form that readily donates electrons to molecular oxygen, but does not reduce NAD+. The catalytic mechanism of both forms of the enzyme can be described in terms of a rapid equilibrium model in which reducing equivalents are distributed rapidly between the different redox centers of the enzyme on the basis of their midpoint potentials. The present commentary gives a brief overview of the literature concerning the rapid equilibrium model and the differences between the two enzyme forms. NADH is also discussed in terms of an alternative to xanthine or hypoxanthine as an electron donor.

NADH oxidase activity of human xanthine oxidoreductase--generation of superoxide anion

Human xanthine oxidase was purified from breast milk. The dehydrogenase form of the enzyme, which predominates in most mammalian tissues, catalyses the oxidation of NADH by oxygen, generating superoxide anion significantly faster than does the oxidase form. The corresponding forms of bovine enzyme behave very similarly. The steady-state kinetics of NADH oxidation and superoxide production, including inhibition by NAD, by the dehydrogenase forms of both enzymes, are analysed in terms of a model involving two-stage recycling of oxidised enzyme. Established inhibitors of xanthine oxidoreductases (allopurinol oxypurinol, amflutizole and BOF 4272), which block all other reducing substrates, were ineffective in the case of NADH. Diphenyleneiodonium, on the other hand, was a powerful inhibitor of NADH oxidation. The potential involvement of reactive oxygen species arising from NADH oxidation by xanthine oxidoreductase in ischaemia-reperfusion injury and other disease states, as well as in normal signal transduction, is discusssed.

[Delayed effects of prenatal exposure to phenobarbital on intelligence--Phenemal]

Two double-blind studies were conducted on two independent samples of adult men prenatally exposed to phenobarbital and matched control samples using two different measures of general intelligence (WAIS and a draft board test (BPP)). The two studies included 33 and 81 exposed adult men respectively, and the two control groups included 52 and 101 unexposed men matched on a wide spectrum of maternal variables recorded pre- and perinatally. Based on data from control subjects, regression models were built relating intelligence scores to relevant pre-exposure matching variables. Models generated predicted scores for each exposed subject. Men exposed prenatally to phenobarbital had significantly lower verbal intelligence scores than predicted. Lower socioeconomic status and being the offspring of an unwanted pregnancy increased the magnitude of the negative effects. Exposure which includes the last trimester was the most detrimental. Physicians are urged to use increased caution in prescribing such medications during pregnancy or to premature neonates.

Psychometric properties of the Danish 16PF and EPQ

A Danish translation of the Cattell's 16PF has been used in studies evaluating the effects of prenatal drug exposure. This paper reports a psychometric analysis of the 16PF and Eysenck's EPQ based on a sample of 558 young Danes. Many 16PF scales had unacceptable psychometric properties (as indicated by coefficient alpha and item--total score correlations), but more satisfactory results were obtained with the EPQ N and E scales. A factor analysis of all 16PF and EPQ scales suggested a six factor solution that roughly corresponds to the second-order factor structure obtained by Krug and Johns (1986). It is concluded that the second-order factor structure should be the basis of interpretation of the 16PF in both practical and research contexts.

In utero exposure to phenobarbital and intelligence deficits in adult men

OBJECTIVE

To test whether exposure to phenobarbital in utero is associated with deficits in intelligence scores in adult men and whether the magnitude of the postnatal effect is mediated by exposure parameters and/or postnatal environmental factors.

DESIGN

Two double-blind studies were conducted on independent samples of adult men prenatally exposed to phenobarbital and matched control samples using different measures of general intelligence. Based on data from control subjects, regression models were built relating intelligence scores to relevant pre-exposure matching variables and age at testing. Models generated predicted scores for each exposed subject. Group mean differences between the individually predicted and observed scores estimated exposure effects.

SETTING

Copenhagen, Denmark.

PARTICIPANTS

Exposed subjects were adult men born at the largest hospital in Copenhagen between 1959 and 1961 who were exposed to phenobarbital during gestation via maternal medical treatment and whose mothers had no history of a central nervous system disorder and no treatment during pregnancy with any other psychopharmacological drug. Study 1 included 33 men and study 2, 81 men. Controls were unexposed members of the same birth cohort matched on a wide spectrum of maternal variables recorded prenatally and perinatally. Controls for studies 1 and 2 included 52 and 101 men, respectively.

MAIN OUTCOME MEASURES

In study 1: Wechsler Adult Intelligence Scale (Danish version); in study 2: Danish Military Draft Board Intelligence Test (Børge Priens Prøve).

RESULT

Men exposed prenatally to phenobarbital had significantly lower verbal intelligence scores (approximately 0.5 SD) than predicted. Lower socioeconomic status and being the offspring of an "unwanted" pregnancy increased the magnitude of the negative effects. Exposure that included the last trimester was the most detrimental.

CONCLUSION

Phenobarbital exposure during early development can have long-term deleterious effects on cognitive performance. Detrimental environmental conditions can interact with prenatal biological insult to magnify negative outcomes. Physicians are urged to use increased caution in prescribing such medications during pregnancy.

High-risk sexual behavior at a midwestern university: a confirmatory survey

According to a 1991 study of sexual behavior based on a random sample of heterosexual undergraduates at a Midwestern university, 80% of the males and 73% of the females had experienced vaginal or anal intercourse. The average age at first vaginal intercourse was 17.2 years for both sexes. Seventeen percent of the sexually experienced males and 18% of the sexually experienced females had engaged in heterosexual anal intercourse; among these respondents, the average age at first anal intercourse was 20.3 for males and 19.1 for females. Although less than four years, on average, had elapsed since the respondents had first had vaginal intercourse, males reported an average of 8.0 lifetime vaginal-sex partners and females reported an average of 6.1. Overall, the findings from this random sample of students are similar to those from a 1988 convenience sample of the same college population.

pH-dependent properties of a mutant horseradish peroxidase isoenzyme C in which Arg38 has been replaced with lysine

Arg38 in the active site of horseradish peroxidase isoenzyme C (HRP-C) has been replaced with lysine by site-directed mutagenesis. As a preclude to a detailed kinetic analysis of this variant, the present study characterizes a pH-dependent cycle of reactions for recombinant horseradish peroxidase isoenzyme C with Arg38 replaced by lysine ([R38K]HRP-C*), which involves time-dependent changes in both specific activity and the electronic absorption spectrum of the enzyme. This pH-dependent cycle resembles that previously suggested for a cytochrome-c peroxidase variant in which Asp235 was replaced with asparagine. When the pH of a solution of resting [R38K]HRP-C* at pH 6.6 (form AH) is raised to pH 8.6, a rapid alkaline transition occurs. This results in spectral changes characteristic of a shift from a predominantly pentacoordinate to a completely hexacoordinate high-spin haem iron (form A-) with a pKa of 7.5. When the pH of a solution of form A- is raised from 8.7 to 12.0, no further spectral changes are observed. The reaction is reversible, but when the high-pH form of the enzyme (A-) is allowed to stand at pH 8.6, it slowly becomes converted into a third enzyme form (form I-) at a rate which is independent of pH (k = 0.56 h-1). When the pH of a sample of form I- is lowered from 8.6 to 6.6, the original low-pH form (AH) of the enzyme is recovered. Recovery of form AH from form I- does not occur via form A-, but via at least one further intermediate, form X. Following a downward pH jump, the rate constant for the formation of form X from form I- shows a small dependence on pH, changing from 48 s-1 at pH 6.8 to 39 s-1 at pH 7.4. The rate of formation of form AH from form X is also pH dependent and biphasic in nature, with measured rate constants ranging from 11.9-2.1 h-1. The possible structures of the different forms of [R38K]HRP-C* are discussed in the light of similar data in the literature for variants of cytochrome-c peroxidase. The properties may be indicative of a greater degree of conformational flexibility within the active site of this mutant caused by the smaller bulk of the lysine side-chain and the probable disruption of a part of the haem-linked hydrogen-bonding network in the distal haem pocket. The wild-type enzyme undergoes no such pH induced changes.

Characterization of recombinant horseradish peroxidase C and three site-directed mutants, F41V, F41W, and R38K, by resonance Raman spectroscopy

Resonance Raman spectra are reported for recombinant horseradish peroxidase C (HRP-C*) and three protein variants prepared by in vitro refolding after Escherichia coli expression. The spectra of their FeII and FeIII forms and of their complexes with benzohydroxamic acid (BHA) were recorded at neutral pH. The residues mutated were on the distal [Phe41-->Trp or Val (F41W, F41V) and Arg38-->Lys (R38K)] side of the heme. The spectra give information on the spin and ligation states via the frequencies of the core size marker bands. No detectable modification in the enzyme structure or in the heme group has been observed in the wild-type recombinant HRP-C*. The FeIII forms of both the recombinant and the plant proteins show the coexistence of a 5-(5-cHS) and a 6-coordinate high-spin (6-cHS) heme, characterized by the anomalous frequencies of certain bands, namely, v3 and v10, which we attribute to a different degree of distortion of the heme planarity with respect to other heme proteins and model compounds, resulting from external forces such as steric contacts within the protein. This effect is partially relieved upon complexation with BHA or as a result of mutation. F41W and F41V are characterized by an increase in a 6-cHS form at the expense of the 5-cHS species, and the R38K by an increase in both the 6-c high-(HS) and low-spin (LS) hemes. The 6-cHS and -LS species are characterized by normal core size marker band frequencies. The FeII-His RR band is at 243 cm-1 in HRP-C*, the high frequency value being due to hydrogen-bonding interactions between the proximal His170 N delta and the carboxylate acceptor group on Asp247. Mutation at position 38 causes a downshift of 3 cm-1 in the v(Fe-Im) stretching mode, suggesting a weakening of the Fe-Im bond strength. By comparing the results obtained with HRP-C* mutants with those previously reported for the corresponding cytochrome c peroxidase (CCP) mutants, it appears that the distal heme pocket architecture is significantly different in the two peroxidases, although the hydrogen-bonding network coupling the distal and the proximal sides of the heme appears to be conserved. Mutations on the distal side dramatically affect the capability of the protein to bind BHA. F41W and R38K mutants do not bind the substrate, whereas the F41V variant shows a 2-fold increase in affinity.(ABSTRACT TRUNCATED AT 400 WORDS)

The Prenatal Development Project

The primary aim of the Prenatal Development Project (PDP) is to evaluate the developmental effects of prenatal exposure to steroid hormones and psychoactive drugs, particularly synthetic progestin, corticosteroids and barbiturates. Data collection has taken place at the Psykologisk Institut, now the Institute of Preventive Medicine, since 1981. The PDP database is unique for its breadth and depth as well as its combination of prospective longitudinal and cross-sectional perspectives. This article describes the database, including subject selection, perinatal information, the comprehensive contemporary evaluation and archival information from Danish registers. The unique matching procedures designed specifically for these projects and data analytic strategies are explained. The value of the PDP database is discussed both in relation to specific project aims (evaluating effects of prenatal drug exposure) and in relation to developmental and psychological research in general.

Characterisation of a haem active-site mutant of horseradish peroxidase, Phe41----Val, with altered reactivity towards hydrogen peroxide and reducing substrates

A horseradish peroxidase variant ([F41V] HRP-C*), in which Val replaces the conserved Phe at position 41 adjacent to the distal His, has been constructed. Its composition and spectroscopic, catalytic and substrate-binding properties were compared with those of the wild-type recombinant (HRP-C*) and plant (HRP-C) enzymes. Presteady-state kinetic measurements of the rate constant for compound I formation (k1) revealed an eightfold decrease in the reactivity of the Phe41----Val variant towards H2O2, in comparison with HRP-C or HRP-C*. Measurement of the remaining rate constants, k2 and k3, for the two single-electron reduction reactions of [F41V] HRP-C with para-aminobenzoic acid as reducing substrate, showed that they were 2.5-fold and 1.3-fold faster, respectively. In contrast, analysis of data from steady-state assays with 2,2'-azinobis(3-ethylbenzthiazoline-6-sulphonate) as reducing substrate, showed decreased reactivity of the mutant enzyme to this compound, indicating a change in substrate specificity. Over the substrate range studied, the data for HRP-C* and for [F41V] HRP-C conformed to a simple modification of the accepted peroxidase mechanism in which a first-order step (ku), assumed to be product dissociation, becomes rate-limiting under our standard assay conditions. Calculations of rate constants from steady-state data yielded values of k1 for both enzyme forms in adequate agreement with those from pre-steady state measurements. They showed, furthermore, that both k3 for 2,2'-azinobis(3-ethylbenzthiazoline-6-sulphonate) and ku were substantially decreased, fivefold and tenfold, respectively, in the mutant. Analogous to the decrease in ku, we observed a twofold increase in the affinity of the mutant variant for the inhibitor benzhydroxamic acid. The coordination-state equilibrium of the haem iron also appeared shifted towards the hexacoordinate high-spin form. These observations indicate that in addition to affecting reactivity to H2O2, mutations in the distal region and close to the haem iron also affect reactivity towards different reducing substrates, inducing perturbations in the neighbourhood of the aromatic-substrate-binding site, known to be 0.8-1.2 nm from the haem iron.

Structural studies by proton-NMR spectroscopy of plant horseradish peroxidase C, the wild-type recombinant protein from Escherichia coli and two protein variants, Phe41----Val and Arg38----Lys

Wild-type recombinant horseradish peroxidase isoenzyme C and two protein variants, Phe41----Val and Arg38----Lys, have been characterised using both one- and two-dimensional NMR spectroscopy. Proton NMR spectra recorded in both resting and cyanide-ligated states of the proteins were compared with those of the corresponding plant peroxidase. The latter contains 18% carbohydrate in eight N-linked oligosaccharide side chains whereas the recombinant proteins are expressed in nonglycosylated form. The spectra of the plant enzyme and refolded recombinant protein are essentially identical with the exception of carbohydrate-linked resonances in the former, indicating that their solution structures are highly similar. This comparison also identifies classes of carbohydrate resonances in the plant enzyme which provides new information on the local environment and mobility of the oligosaccharide side chains. Comparison of the spectra of the cyanide-ligated states of the two variants and those of plant horseradish peroxidase C indicated that there were significant differences with respect to haem and haem-linked resonances. These could not be rationalised simply on the basis of the local perturbation expected from a single-site substitution. The two substitutions made to residues on the distal side of the haem apparently influenced the degree of imidazolate character of the proximal His170 imidazole ring thus perturbing the magnetic environment of the haem group. Inspection of the spectra of the Phe41----Val variant also showed that the resonances of a phenylalanine residue in the haem pocket had been incorrectly assigned to Phe41 in a previous study. A new assignment, based on additional information from two-dimensional nuclear Overhauser enhancement spectroscopy, was made to Phe152. The assignments made for the Phe41----Val variant were also used as a basis to investigate the structure of the complex formed with the aromatic donor molecule, benzhydroxamic acid.

High-risk sexual behavior among heterosexual undergraduates at a midwestern university

Approximately 80% of a self-selected sample of 593 heterosexual undergraduate college students studied at a large Midwestern state university in 1988 had ever experienced penile-vaginal or penile-anal intercourse. One-fifth of the 477 sexually experienced women and men said they had had heterosexual and intercourse. The mean age at first vaginal intercourse was 17, while the mean age at first anal intercourse was about 18.5. Although less than four years, on average, had elapsed since the respondents' first vaginal or anal intercourse, females reported having had an average of 5.6 sexual partners, and males reported an average of 11.2 partners.

Effects of prenatal exposure to diethylstilbestrol (DES) on hemispheric laterality and spatial ability in human males

Ten males exposed to diethylstilbestrol (DES), a nonsteroidal synthetic estrogen, during gestation were compared to their matched, unexposed brothers on measures of brain hemispheric specialization for processing nonlinguistic spatial information and cognitive abilities. DES exposure was associated with reduced hemispheric laterality and lowered spatial ability. These data provide direct evidence of a relationship between brain laterality, spatial cognitive ability, and prenatal exposure to hormones in human males. Further, the implications of these findings for understanding sexual differentiation of the human brain are discussed.

Hormonal contributions to sexually dimorphic behavioral development in humans

Nineteen studies on the behavioral effects of prenatal exposure to hormones administered for the treatment of at-risk human pregnancy are reviewed. Because the role of prenatal exposure to hormones in the development of human behavioral sex differences is potentially confounded by society's differential treatment of the sexes, comparisons between exposed and unexposed subjects were evaluated and summarized separately for male and female subjects. Therefore, this review focuses on data for individuals whose prenatal hormone environments were atypical relative to what is normal for their own sex. Overall, it appears that prenatal exposure to androgen-based synthetic progestin exerted a masculinizing and/or defeminizing influence on human behavioral development, whereas prenatal exposure to natural progesterone and progesterone-based synthetic progestin had a feminizing and/or demasculinizing influence, particularly among female subjects. The data on prenatal exposure to synthetic estrogen derive primarily from subjects exposed to diethylstibestrol (DES). DES-exposed male subjects appeared to be feminized and/or demasculinized, and there is some evidence that exposed female subjects were masculinized. These findings are discussed in the context of prenatal hormonal contributions to sexually dimorphic behavioral development both within and between the sexes. Recommendations for the conduct of future research in developmental behavioral endocrinology are presented.

Development of a tool to measure subjective time experience

Although variations in time experience in specific health-illness situations have been documented, the information has not been systematically described. This is due in part to lack of reliable and valid measurement of time experience. This article, which reports the development and testing of Time Experience Scales (TES) in a sample of healthy adults, represents preliminary work in the identification of temporal experience in ill persons. Subjective time experience was defined as thoughts and feelings about the temporal frame in which life events occur. Semantic differential and Likert scale items indicated four conceptual dimensions of subjective time experience. A mail questionnaire was distributed to a purposive sample of community-based healthy adults. Data were analyzed separately for men (n = 587) and women (n = 475). Factor analysis methods resulted in the emergence of six robust empirical factors: meaning, fast tempo, slow tempo, attention to death, future orientation, and past orientation. Product moment correlations between scales (.01 to .45) indicated the validity, and coefficient alpha (.68 to .88) the reliability of measurement, using the factors. Results suggest that at least six distinct temporal experiences help people assign order, rhythm, and meaning to life events, thereby creating a continuing and optimal life story. Further reliability and validity testing is suggested.

A test of sex differences in aggressive response to hypothetical conflict situations

Male (n = 289) and female (n = 268) college students were administered the Leifer-Roberts Response Hierarchy (Reinisch Revision) to evaluate the utility of this measure in reflecting sex differences in self-described potential for aggressive response. The Response Hierarchy provides a retrospective estimate of where physical and verbal aggression reside in an individual's hierarchy of possible behavioral responses to hypothetical conflict situations in adolescence. A score is obtained for: (a) physical aggression, (b) verbal aggression, (c) nonaggressive coping, and (d) withdrawal. When asked to respond as they would have or did at age 13 years, verbal aggression was the most frequent response with no significant sex difference in mean scores. Men selected physical aggression significantly more often than women (p less than .001). Using the binomial effect size display (BESD) to illustrate the magnitude of the sex difference, 69% of the men would be classified as physically aggressive (above the median), whereas only 31% of the women would be so classified. It was concluded that the Response Hierarchy consistently demonstrates sex differences among college students in retrospectively reported preference for choosing physical aggression versus other coping strategies as a response to hypothetical interpersonal conflict situations of adolescence.

A test of sex differences in aggressive response to hypothetical conflict situations

Male (n = 289) and female (n = 268) college students were administered the Leifer-Roberts Response Hierarchy (Reinisch Revision) to evaluate the utility of this measure in reflecting sex differences in self-described potential for aggressive response. The Response Hierarchy provides a retrospective estimate of where physical and verbal aggression reside in an individual's hierarchy of possible behavioral responses to hypothetical conflict situations in adolescence. A score is obtained for: (a) physical aggression, (b) verbal aggression, (c) nonaggressive coping, and (d) withdrawal. When asked to respond as they would have or did at age 13 years, verbal aggression was the most frequent response with no significant sex difference in mean scores. Men selected physical aggression significantly more often than women (p less than .001). Using the binomial effect size display (BESD) to illustrate the magnitude of the sex difference, 69% of the men would be classified as physically aggressive (above the median), whereas only 31% of the women would be so classified. It was concluded that the Response Hierarchy consistently demonstrates sex differences among college students in retrospectively reported preference for choosing physical aggression versus other coping strategies as a response to hypothetical interpersonal conflict situations of adolescence.

Herpes simplex encephalitis

This is an acute necrotizing encephalitis with a high mortality rate. It is thought to occur by the reactivation of herpes simplex virus type 1 from latently infected trigeminal ganglia, with subsequent centripetal spread and fulminant growth in tissue of the central nervous system. Prompt diagnosis and antiviral therapy are required because of the rapidly progressive nature and severe consequences of this disease. The physician must understand the pathophysiology to fully appreciate the need for early diagnosis and the gravity of mismanagement.

Palatability and meal patterns

Investigations of palatability have often been confounded by nutritional, pharmacological or methodological problems. The present experiment examined the free-feeding meal patterns of two differentially preferred yet nutritionally equivalent diets. When the two diets were offered sequentially (Experiment 1), no differences were found in meal frequency, meal size, or meal duration. However, when the diets were offered simultaneously in Experiment 2, the preferred diet was consumed more frequently, in larger meals, and at a faster feeding rate than the less preferred diet. Further, the meal patterns in Experiment 2 of the preferred diet were identical with those found for both diets in Experiment 1. Therefore, the meal patterns of two diets with differing palatability depend upon the method of presentation with differences appearing when the diets are offered simultaneously but not when they are offered sequentially.

Early barbiturate exposure: the brain, sexually dimorphic behavior and learning

Barbiturates, one of the most widely prescribed and abused classes of drugs, reportedly have been prescribed in as many as 25% of pregnancies in the U.S. and Europe over the last 30 years. Nevertheless, there exists little if any data on long-term consequences of prenatal exposure to barbiturates in humans. Evidence from laboratory animals indicates that exposure to barbiturates during early developmental periods results in abnormal neural and biochemical differentiation of the central nervous system, deficits in learning, retarded attainment of developmental milestones, alteration of behavioral and physiological sex differences, increased activity, and decreased responsiveness to aversive and appetitive stimuli. Barbiturates appear to influence the brain via two routes: (1) by direct action on neural tissue; and (2) indirectly by altering hepatic metabolism of steroid hormones. It is concluded that prenatal exposure to barbiturates in human subjects may lead to learning disabilities, decreased IQ, performance deficits, increased incidence of psychosocial maladjustment, and demasculinization of gender identity and sex role behavior in males.