Mothers’ and fathers’ engagement in math activities with their toddler sons and daughters: The moderating role of parental math beliefs

Parents’ beliefs about the importance of math predicts their math engagement with their children. However, most work focuses on mothers’ math engagement with preschool- and school-aged children, leaving gaps in knowledge about fathers and the experiences of toddlers. We examined differences in mothers’ and fathers’ (N = 94) engagement in math- and non-math activities with their two-year-old girls and boys. Parents reported their beliefs about the importance of math and literacy for young children and their frequency of home learning activities. Parents of sons did not differ in their engagement in math activities from parents of daughters. Mothers reported engaging more frequently in math activities with their toddlers than fathers did, but the difference reduced when parents endorsed stronger beliefs about the importance of math for children. Even at very early ages, children experience vastly different opportunities to learn math in the home, with math-related experiences being shaped by both parent gender and parents’ beliefs.

The Early Motor Questionnaire revisited: Starting points, standardized scores, and stability

Motor skills are an important aspect of development during infancy and have been found to predict development in other domains. Therefore, fast and reliable assessments of infant motor skills are needed. The current study revisited a time and cost-effective parent-report measure of infants' motor skills-the Early Motor Questionnaire (EMQ)-and aimed to improve the utility of the EMQ as a tool to examine variability, stability, and individual differences in early motor development. A sample of 446 parents of infants provided a total of 775 EMQ responses for analyses. Using this large sample, regression was used to create age-independent scores for global, gross motor, fine motor, and perception-action scores on the EMQ. Age-adjusted scores were then converted to t-scores to facilitate score interpretation for past and future studies using the EMQ. Finally, starting flags for different age groups were created to decrease the time it takes parents to complete the EMQ. Together, these changes to the EMQ will improve the utility and interpretability of the measure. The EMQ is free to use and available in the supplemental materials or via www.onlinebabylab.com/emq.

Genetic variation within the human papillomavirus type 16 genome is associated with oropharyngeal cancer prognosis

PURPOSE

A significant barrier to adoption of de-escalated treatment protocols for human papillomavirus-driven oropharyngeal cancer (HPV-OPC) is that few predictors of poor prognosis exist. We conducted the first large whole-genome sequencing (WGS) study to characterize the genetic variation of the HPV type 16 (HPV16) genome and to evaluate its association with HPV-OPC patient survival.

PATIENTS AND METHODS

A total of 460 OPC tumor specimens from two large United States medical centers (1980-2017) underwent HPV16 whole-genome sequencing. Site-specific variable positions [single nucleotide polymorphisms (SNPs)] across the HPV16 genome were identified. Cox proportional hazards model estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for overall survival by HPV16 SNPs. Harrell C-index and time-dependent positive predictive value (PPV) curves and areas under the PPV curves were used to evaluate the predictive accuracy of HPV16 SNPs for overall survival.

RESULTS

A total of 384 OPC tumor specimens (83.48%) passed quality control filters with sufficient depth and coverage of HPV16 genome sequencing to be analyzed. Some 284 HPV16 SNPs with a minor allele frequency ≥1% were identified. Eight HPV16 SNPs were significantly associated with worse survival after false discovery rate correction (individual prevalence: 1.0%-5.5%; combined prevalence: 15.10%); E1 gene position 1053 [HR for overall survival (HRos): 3.75, 95% CI 1.77-7.95; Pfdr = 0.0099]; L2 gene positions 4410 (HRos: 5.32, 95% CI 1.91-14.81; Pfdr = 0.0120), 4539 (HRos: 6.54, 95% CI 2.03-21.08; Pfdr = 0.0117); 5050 (HRos: 6.53, 95% CI 2.34-18.24; Pfdr = 0.0030), and 5254 (HRos: 7.76, 95% CI 2.41-24.98; Pfdr = 0.0030); and L1 gene positions 5962 (HRos: 4.40, 95% CI 1.88-10.31; Pfdr = 0.0110) and 6025 (HRos: 5.71, 95% CI 2.43-13.41; Pfdr = 0.0008) and position 7173 within the upstream regulatory region (HRos: 9.90, 95% CI 3.05-32.12; Pfdr = 0.0007). Median survival time for patients with ≥1 high-risk HPV16 SNPs was 3.96 years compared with 18.67 years for patients without a high-risk SNP; log-rank test P < 0.001. HPV16 SNPs significantly improved the predictive accuracy for overall survival above traditional factors (age, smoking, stage, treatment); increase in C-index was 0.069 (95% CI 0.019-0.119, P < 0.001); increase in area under the PPV curve for predicting 5-year survival was 0.068 (95% CI 0.015-0.111, P = 0.008).

CONCLUSIONS

HPV16 genetic variation is associated with HPV-OPC prognosis and can improve prognostic accuracy.

Associations between oral health and general health: a surveywide association study of the NHANES

OBJECTIVE

This proof of concept study uses data from the National Health and Nutrition Examination Survey (NHANES) to explore potential associations between oral and systemic health in a survey-wide association study (SWAS).

BASIC RESEARCH DESIGN

Data from n=9,971 records in the 2015-2016 NHANES survey were used to evaluate associations between self-rated oral health and the various systemic health conditions that are included in the survey. Associations were estimated using survey-weighted linear regression models adjusted for age, sex, race, and smoking status.

RESULTS

Substantial associations with self-rated oral health were evident after correction for multiple comparisons. The study revealed associations in categories of mental health, cardiovascular disease, and diabetes adding to the body of evidence. The study also suggested associations with physical functioning, vision, hearing, genitourinary symptoms, and the prevalence of hepatitis.

CONCLUSIONS

The SWAS method demonstrated the ability to identify associations between oral health and systemic health. Suggested associations should be investigated further investigated with emphasis on both biologic and societal mechanisms. The noteworthy associations with mental health, physical activity, and cardiovascular disease in this study inform clinicians from each of these disciplines that they may benefit from collaborations with oral health care providers to promote whole-person health.

Lack of consistent sex differences in D-amphetamine-induced dopamine release measured with [18F]fallypride PET

RATIONALE

Sex differences in the dopaminergic response to psychostimulants could have implications for drug abuse risk and other psychopathology involving the dopamine system, but human data are limited and mixed.

OBJECTIVES

Here, we sought to investigate sex differences in dopamine release after oral D-amphetamine administration.

METHODS

We used [¹⁸F]fallypride positron emission tomography (PET) to measure the change in dopamine D2/3 receptor availability (%ΔBP_ND, an index of dopamine release) between placebo and D-amphetamine sessions in two independent datasets containing a total of 39 females (on either hormonal birth control n = 18, postmenopausal n = 10, or studied in the first 10 days of their menstrual cycle n = 11) and 37 males.

RESULTS

Using both a priori anatomical regions of interest based on previous findings and voxelwise analyses, we failed to consistently detect broad sex differences in D-amphetamine-induced dopamine release. Nevertheless, there was limited evidence for greater right ventral striatal dopamine release in young adult males relative to similarly aged females, but this was not consistently observed across samples. Plasma estradiol did not correlate with dopamine release and this measure did not differ in females on and off hormonal birth control.

CONCLUSIONS

While our finding in young adults from one dataset of greater %ΔBP_ND in males is partially consistent with a previously published study on sex differences in D-amphetamine-induced dopamine release, our data do not support the presence of consistent widespread sex differences in this measure of dopamine release.

The Online Social Support Scale: Measure development and validation

A new measure, the Online Social Support Scale, was developed based on previous theory, research, and measurement of in-person social support. It includes four subscales: Esteem/Emotional Support, Social Companionship, Informational Support, and Instrumental Support. In college and community samples, factor analytic and item response theory results suggest that subtypes of in-person social support also pertain in the online world. Evidence of reliability, convergent validity, and discriminant validity provide excellent psychometric support for the measure. Construct validity accrues to the measure vis-à-vis support for three hypotheses: (a) Various broad types of Internet platforms for social interactions are differentially associated with online social support and online victimization; (b) similar to in-person social support, online social support offsets the adverse effect of negative life events on self-esteem and depression-related outcome; and (c) online social support counteracts the effects of online victimization in much the same way that in-person friends in one social niche counterbalance rejection in other social niches. (PsycINFO Database Record

A non-synonymous single nucleotide polymorphism in IFNAR1 affects susceptibility to chronic hepatitis B virus infection

The type I interferon (IFN-alpha/beta) receptor 1 (IFNAR1) mediates the potent antiviral and immuno-regulatory effects of IFN-alpha/beta that are believed to be pivotal to eradicate hepatitis B virus (HBV) infection. IFNAR1 promoter polymorphisms (at -568/-77) have been shown to be associated with susceptibility to chronic HBV infection; however, whether these markers are genetic determinants of HBV infection remains unknown. The functional significance of promoter -568/-77 polymorphisms was assessed by mutagenesis and luciferase assays. Sequencing and restriction fragment length polymorphisms in 328 chronic HBV patients, 130 spontaneous resolvers and 148 healthy blood donors identified other polymorphism at IFNAR1 open reading frame. IFNAR1 expression levels in peripheral blood cells were detected by flow cytometry. We found that the -568/-77 promoter variants were unlikely to affect transcription levels. A C/G single nucleotide polymorphism, in strong linkage disequilibrium with the promoter polymorphisms, was found in the coding sequence of IFNAR1 (nt19158). This resulted in a nonsynonymous substitution in the extracellular region of IFNAR1 protein and correlated with susceptibility to chronic HBV infection. Bioinformatic analysis suggested decreased stability of the IFNAR1 protein. Chronic HBV patients with the 19158C/C genotype (Leu141) exhibited higher IFNAR1 protein expression levels in peripheral blood monocytes than those with the 19158G/G genotype (Val141). In conclusion, IFNAR1 19158C/G polymorphism is primarily associated with susceptibility to chronic HBV infection.

Central role of detachment faults in accretion of slow-spreading oceanic lithosphere

The formation of oceanic detachment faults is well established from inactive, corrugated fault planes exposed on sea floor formed along ridges spreading at less than 80 km Myr(-1) (refs 1-4). These faults can accommodate extension for up to 1-3 Myr (ref. 5), and are associated with one of the two contrasting modes of accretion operating along the northern Mid-Atlantic Ridge. The first mode is asymmetrical accretion involving an active detachment fault along one ridge flank. The second mode is the well-known symmetrical accretion, dominated by magmatic processes with subsidiary high-angle faulting and the formation of abyssal hills on both flanks. Here we present an examination of approximately 2,500 km of the Mid-Atlantic Ridge between 12.5 and 35 degrees N, which reveals asymmetrical accretion along almost half of the ridge. Hydrothermal activity identified so far in the study region is closely associated with asymmetrical accretion, which also shows high levels of near-continuous hydroacoustically and teleseismically recorded seismicity. Increased seismicity is probably generated along detachment faults that accommodate a sizeable proportion of the total plate separation. In contrast, symmetrical segments have lower levels of seismicity, which occurs primarily at segment ends. Basalts erupted along asymmetrical segments have compositions that are consistent with crystallization at higher pressures than basalts from symmetrical segments, and with lower extents of partial melting of the mantle. Both seismic evidence and geochemical evidence indicate that the axial lithosphere is thicker and colder at asymmetrical sections of the ridge, either because associated hydrothermal circulation efficiently penetrates to greater depths or because the rising mantle is cooler. We suggest that much of the variability in sea-floor morphology, seismicity and basalt chemistry found along slow-spreading ridges can be thus attributed to the frequent involvement of detachment faults in oceanic lithospheric accretion.

Assessing field-scale migration of radionuclides at the Nevada Test Site: "mobile" species

Many long-lived radionuclides are present in groundwater at the Nevada Test Site (NTS) as a result of 828 underground nuclear weapons tests conducted between 1951 and 1992. In conjunction with a comprehensive geochemical review of radionuclides (3H, 14C, 36Cl, 99Tc and 129I) that are presumably mobile in the subsurface, we synthesized a body of radionuclide activity data measured from groundwater samples collected at 18 monitoring wells, to qualitatively assess their migration at the NTS over distances of hundreds of meters and over timescales of decades. Tritium and 36Cl showed little evidence of retardation, while the transport of 14C may have been retarded by its isotopic exchange with carbonate minerals in the aquifer. Observed local reducing conditions (either natural or test-induced) will impact the mobility of certain redox-sensitive radionuclides (especially 99Tc) that were otherwise soluble and readily transported under oxidizing conditions. Conversely, strongly oxidizing conditions may impact the mobility of 129I which is mobile under reducing conditions. The effect of iodine speciation on its transport deserves further attention. Indication of delayed transport of some "mobile" radionuclides (especially 99Tc) in the groundwater at the NTS suggested the importance of redox conditions of the natural system in controlling the fate and transport of radionuclides, which has implications in the enhanced performance of the potential Yucca Mountain repository, located adjacent to the NTS, to store high-level nuclear wastes as well as management of radionuclide contamination in legacy nuclear operations facilities.

A family with osteoporosis pseudoglioma syndrome due to compound heterozygosity of two novel mutations in the LRP5 gene

Osteoporosis pseudoglioma syndrome (OPPG) is an autosomal recessive disorder due to mutations in the low-density lipoprotein receptor-related protein 5 (LRP5) gene. Here, we report two novel missense mutations found in a southern Chinese family of a non-consanguineous marriage. Three out of four children had blindness, low bone mineral density (BMD) and multiple fractures in their childhood. Genotyping by DNA sequencing demonstrated 2 new mutations in exon 7 of the LRP5 gene. Tryptophans at amino acid residue positions 478 and 504 were replaced by arginine (W478R) and cysteine (W504C), respectively. While the parents that possessed either heterozygous W478R or W504C were apparently normal, all affected subjects were compound heterozygotes for the W478R and W504C mutations in the LRP5 gene. W478R is located immediately C-terminal to the third YWTD repeat of the second YWTD/EGF domain in LRP5, while W504C is located between the third and the fourth YWTD repeats of the second YWTD/EGF domain in LRP5. Using LRP5-related proteins, such as the low-density lipoprotein receptor (LDLR) and nidogen as reference models, a homology model of LRP5 suggested that the observed mutations may affect the molecular interactions of LRP5 and so lead to the observed OPPG phenotypes.

An inventory of long-lived radionuclides residual from underground nuclear testing at the Nevada test site, 1951-1992

An inventory of long-lived radionuclides produced by 828 underground nuclear tests conducted at the Nevada test site (NTS) from 1951 to 1992 includes residual tritium, fission products, actinides, and activation products. Recently, the US Department of Energy approved the declassification of the NTS radionuclide inventory by principal geographic test centers. This permits unclassified publication of radionuclide totals for the Yucca Flat, Pahute Mesa-Area 19, Pahute Mesa-Area 20, Frenchman Flat, and Rainier Mesa/Shoshone Mountain testing locations. Activities are reported as of September 23, 1992, the date of the last underground nuclear test conducted at the NTS, and September 23, 2492, after 500 years of radioactive decay. The availability of these data affords an opportunity for the analysis of the radiologic source term within the boundaries of local hydrogeologic units and provides insight to where radionuclides are sited relative to potential exposure pathways.

Regional variation in CCR5-Delta32 gene distribution among women from the US HIV Epidemiology Research Study (HERS)

The CCR5-Delta32 genotype is known to influence HIV-1 transmission and disease. We genotyped 1301 US women of various races/ethnicities participating in the HIV Epidemiologic Research Study. None was homozygous for CCR5-Delta32. The distribution of heterozygotes was similar in HIV-1 infected and uninfected women. Thirty-seven (11.8%) white, 28 (3.7%) blacks/African Americans (AA), seven (3.3%) Hispanics/Latinas, and one (6.6%) other race/ethnicity were heterozygous. The frequency of heterozygotes differed among sites for all races combined (P = 0.001). More heterozygotes were found in AA women in Rhode Island (8.9%) than in the other sites (3.1%) (P = 0.02), while heterozygosity in white women was most common in Maryland (28.6%) (P = 0.025). These regional differences could be accounted for by racial admixture in AAs, but not in whites. Regional variations should be considered when studying host genetic factors and HIV-1 in US populations.

High-performance liquid chromatography applications of optical rotation detection with compensation for scattering and absorbance at the laser wavelength

Use of instrumentation developed to enable simultaneous monitoring of optical rotation (OR) and transmittance allows OR measurements to be made in the presence of high levels of absorbance, scattering or other effects that change the intensity of the plane-polarised light at the photodiode detector. This extends the application of OR detection to areas where it was previously difficult. Examples of the application of high-performance liquid chromatography (HPLC) with the improved OR detector include (i) the analytical scale separation of fructose and sucrose and (ii) the semi-preparative separation of enantiomers of warfarin and Trögers base. A signal-to-noise improvement of up to 150% is found when comparing signals with and without correction for transmittance changes. The improved OR detector has been used in series with a UV detector and the system shown to be suitable for on-line measurement of peak purity in separations using a chiral column under overload conditions.

Rapid diagnostic evaluation of bronchial washings in patients with suspected coccidioidomycosis

Coccidioidomycosis is a regionally common fungal infection, primarily affecting the lung. While in the majority of cases the tempo of the disease allows for a more leisurely diagnostic plan, including multiple serologic tests and culture of respiratory secretions, occasionally, patients will present with rapidly progressive, life-threatening pulmonary illness, in whom there is an urgent need for rapid diagnosis. Evaluation of respiratory secretions including expectorated sputum as well as bronchial washings are frequently available or obtained for diagnosing pulmonary infiltrates. We compared the sensitivity of the Papanicolaou stain with 10% potassium hydroxide digestion (10% KOH) and with calcofluor white (cw). The Papanicolaou test performed the best and should be used in the evaluation of suspected patients with coccidioidomycosis.

Cancer incidence in women with or at risk for HIV

The purpose of our study was to identify the types and rates of cancers seen in high-risk human immunodeficiency virus (HIV)-infected and HIV-uninfected women. From 1993 to 1995, 1,310 women enrolled at four urban U.S. research sites in the HIV Epidemiology Research Study and were interviewed biannually to identify interval diagnoses and hospitalizations until study closure in March 2000. Cancer incidence data were collected through abstraction of medical records and death certificates. Of 871 HIV-infected and 439 HIV-uninfected women, 85% had a history of smoking and 50% a history of injection drug use. For our analysis, 4,180 person-years were contributed by HIV-infected women, and 2,308 person-years by HIV-uninfected women. HIV-infected women had 8 non-Hodgkin's lymphomas, 5 invasive cervical cancers (ICC), 1 Kaposi's sarcoma and 12 non-AIDS defining cancers, including 4 lung cancers, compared with 4 cancers in HIV-uninfected women including 1 lung cancer (all cancers, 6.22/1000 person-years vs. 1.73/1000 person-years, p = 0.01). CD4+ cell counts were above 200/mm3 in all women with ICC. HIV-infected women with lung cancer were young smokers (mean age, 40 years), and all died within 6 months of diagnosis. Lung cancer occurred at twice the rate in HIV-infected vs. uninfected women in the cohort and severalfold above expected in age- and race-matched women in U.S. national data (incidence relative risk 6.39; 95% confidence interval 3.71, 11.02; p < 10(-7)). The frequent occurrence of cervical and lung cancers have important implications for the counseling (cigarette cessation), screening (PAP smears) and care of women with HIV infection, as they live longer because of current antiretroviral therapies.

Supramolecular solubilisation of hydrophilic dyes by using individual dendritic branches

Individual dendritic branches can solubilise hydrophilic dyes in apolar media. The functional group at the focal point of the dendritic branch plays a key role in the dye uptake process. Supramolecular interactions between carboxylic acid and amine groups have been shown to be effective in enabling efficient solubilisation to occur. The necessary complementarity of this interaction is further illustrated by a series of control experiments. The extent of dendritic branching (i.e. dendritic generation) plays a key role in controlling the extent of dye uptake, with higher-generation dendritic branches exhibiting more efficient uptake at lower concentrations. UV/Visible spectroscopic methods have shown that the dendritic branches, in addition to the tuning of the extent of dye uptake, also tune the optical properties of the solubilised dye and this provides further insight into the interactions occurring between the solubilised dye and the individual dendritic branches. Furthermore, it is shown that suitably functionalised dendritic branches can transport hydrophilic dyes through an apolar phase and deliver them continuously into an aqueous medium.

A dendritic active site: catalysis of the Henry reaction

[reaction: see text] Dendrimers containing an encapsulated tertiary amine were prepared by coupling tris(2-aminoethyl)amine with dendritic branches derived from L-lysine. These dendrimers were used as catalysts in the Henry (nitroaldol) reaction between 4-nitrobenzaldehyde and nitroethane, and their catalytic performance was compared with that of triethylamine. Attachment of the dendritic shell alters the rate of reaction and influences the syn:anti ratio of products. It is proposed that the dendritic shell generates an encapsulated catalytically active site, mimicking the behavior of a protein superstructure.

Antiretroviral regimen complexity, self-reported adherence, and HIV patients' understanding of their regimens: survey of women in the her study

BACKGROUND

Research regarding treatment adherence in chronic diseases, such as hypertension, suggests that increasing complexity in the medication regimen is associated with decreasing patient adherence. However, less is known about the relationship between regimen complexity and adherence in the treatment of HIV/AIDS.

OBJECTIVE

To examine the relationship between antiretroviral (ART) regimen complexity and patient understanding of correct regimen dosing to adherence (missing doses in the past 1 and 3 days).

METHODS

Cross-sectional survey of a cohort of women living with HIV/AIDS and enrolled in the HER (HIV Epidemiologic Research) Study.

RESULTS

Seventy-five percent of patients correctly understood the dosing frequency of their ART medications, 80% understood the food-dosing restrictions, whereas only 63% understood both. The percentage of patients with a correct understanding of dosing decreased with increasing regimen complexity (increased dosing frequency and food-dosing restrictions). Patients were more likely to have missed doses in the previous 3 days if they were taking ART medications three or more times per day or had to take one or more antiretrovirals on an empty stomach. A multivariate logistic regression model demonstrated that patients with less complex regimens (twice daily or less in frequency, no food-dosing restrictions) who correctly understood the dosing and food restrictions of their ART regimen were less likely to have skipped doses in the past three days (odds ratio [OR], 0.4; 95% confidence interval [CI], 0.2-0.7) than those with more complex regimens. Younger age and higher CD4 count were also associated with a reduced likelihood of skipping doses. No association was found between adherence and race/ethnicity, current or past injection drug use, or education.

CONCLUSIONS

Self-reported adherence is better among patients with less complex ART regimens. This is in part because patients' understanding of regimen dosing decreases as regimen complexity increases. Therefore, simplifying antiretroviral regimens may have an important role in improving patients' adherence.

Influence of injection drug use behavior on reported antiretroviral therapy use among women in the HIV Epidemiology Research study: on-site versus referral care

BACKGROUND

HIV-infected injection drug users consistently report poor antiretroviral therapy use and little contact with health care providers. It has been suggested that the clinical setting where patients are seen affects the use of highly active antiretroviral therapy.

OBJECTIVES

The purpose of this study was to determine whether ease of access to medical care affects self-report of taking antiretroviral therapy, particularly among female injection drug users.

DESIGN

The study is a cross-sectional analysis from a prospective cohort study of HIV-infected women.

SETTING

Women were enrolled at four sites in the United States: Detroit, Michigan, and Providence, Rhode Island, where on-site HIV care and treatment were offered, and Baltimore, Maryland, and the Bronx, New York, where all participants were referred elsewhere for HIV care and treatment.

PATIENTS

Patients were HIV-infected women with no AIDS diagnosis or women who were at risk for HIV infection either through self-reported injection drug use since 1985 or through sexual contact.

MEASUREMENTS

The study measured self-reported use of antiretroviral therapy (ART) alone or combined with Pneumocystis carinii (PCP) prophylaxis in the previous 6 months.

RESULTS

In multivariate analysis including type of study site (on-site compared with referral care) and injection drug use, any self-reported ART use associated with low CD4 cell count category, older age, and race. However, at on-site care centers, women were equally likely to report ART use regardless of current, former, or no injection drug use, whereas at referral sites only women identified as sexual contacts were more likely to report any ART use, independent of all other variables.

CONCLUSIONS

Easy access to medical care has an important impact on HIV-infected women receiving ART, particularly those who are active injection drug users.

Pig-tailed macaques infected with human immunodeficiency virus (HIV) type 2GB122 or simian/HIV89.6p express virus in semen during primary infection: new model for genital tract shedding and transmission

Characterizing human immunodeficiency virus (HIV) expression in semen during primary infection remains essential to understanding the risk of sexual transmission. This investigation represents the first systematic evaluation of male genital tract shedding to use a nonhuman primate model, including the impact of exposure route and viral virulence. Male macaques were inoculated with either a chronic disease-causing virus (HIV-2(GB122); n=4 intravenous; n=4 intrarectal) or an acutely pathogenic simian/HIV strain (SHIV(89.6P); n=2 intravenous). All macaques were systemically infected, and seminal plasma virion-associated RNA (vRNA) levels were approximately 10-fold lower than those in blood. In HIV-2(GB122) infection, seminal virus was delayed by 1-2 weeks compared with that in blood. Intrarectal inoculation resulted in a shorter duration of seminal vRNA expression and intermittent seminal cell provirus. No delays, higher peaks ( approximately 50-fold), or longer durations in seminal virus expression were noted for SHIV(89.6P) infection. This novel model definitively establishes that virus dissemination results in early peak seminal levels and provides a basis for evaluating interventions targeting male genital tract expression.

Multicenter evaluation of hepatitis C RNA levels among female injection drug users

The purpose of this investigation was to identify factors that determine the blood level of hepatitis C virus (HCV) RNA. By use of a quantitative polymerase chain reaction assay, the level of HCV RNA was ascertained in stored serum samples from 676 women enrolled in a multicenter prospective investigation who were seropositive for anti-HCV antibodies. HCV RNA levels ranged from undetectable to 22.4x106 copies/mL in these women. Among the 520 women with detectable HCV RNA, levels were higher among those who were >41 years old and those who had human immunodeficiency virus (HIV) infection. After adjusting for age in a multivariate linear regression model, HCV RNA levels were more strongly associated with HIV RNA levels than with CD4(+) lymphocyte counts. However, <6% of person-to-person variance was explained by the factors evaluated. Additional research is needed to ascertain what determines the level of HCV RNA in blood.

HIV infection in women in the United States: status at the Millennium

CONTEXT

During the past decade, knowledge of human immunodeficiency virus (HIV) infection in women has expanded considerably but may not be easily accessible for use in understanding and prioritizing the clinical needs of HIV-infected women.

OBJECTIVES

To perform a comprehensive review of epidemiologic, clinical, psychosocial, and behavioral information about HIV in women, and to recommend an agenda for future activities.

DATA SOURCES

A computerized search, using MEDLINE and AIDSline, of published literature was conducted; journal articles from January 1981 through July 2000 and scientific conference presentations from January 1999 through July 2000 were retrieved and reviewed for content; article reference lists were used to identify additional articles and presentations of interest.

STUDY SELECTION

Data from surveillance and prospective cohort studies with at least 20 HIV-infected women and appropriate comparison groups were preferentially included.

DATA EXTRACTION

Included studies of historical importance and subsequent refined analyses of topics covered therein; these and studies with more current data were given preference. Four studies involving fewer than 20 women were included; 2 studies were of men only.

DATA SYNTHESIS

Women account for an increasing percentage of all acquired immunodeficiency syndrome (AIDS) cases, from 6.7% (1819/27 140 cases) in 1986 to 18% (119 810/724 656 cases) in 1999. By the end of 1998, of all newly reported AIDS cases among women, proportionally more were in the South (41%), among black women (61%), and from heterosexual transmission (38%). Of note, increasingly more women have no identified or reported risk, about half or more of whom are estimated to be infected heterosexually. It is estimated that a total of at least 54% of women newly reported with AIDS in 1998 acquired HIV through heterosexual sex, including women in the no identified or reported risk category estimated to have been infected heterosexually, meeting the surveillance heterosexual risk definition. Natural history, progression, survival, and HIV-associated illnesses-except for those of the reproductive tract-thus far appear to be similar in HIV-infected women and men. Although antiretroviral therapy has proven to be highly effective in improving HIV-related morbidity and mortality rates, women may be less likely than men to use these therapies. Drug use, high-risk sex behaviors, depression, and unmet social needs interfere with women's use of available HIV prevention and treatment resources.

CONCLUSIONS

Continued research on HIV pathogenesis and treatment is needed; however, emphasis should also be placed on using existing knowledge to improve the clinical care of women by enhancing use of available services and including greater use of antiretroviral therapy options, treating depression and drug use, facilitating educational efforts, and providing social support for HIV-infected women.

Dendritic biomimicry: microenvironmental hydrogen-bonding effects on tryptophan fluorescence

Two series of dendritically modified tryptophan derivatives have been synthesised and their emission spectra measured in a range of different solvents. This paper presents the syntheses of these novel dendritic structures and discusses their emission spectra in terms of both solvent and dendritic effects. In the first series of dendrimers, the NH group of the indole ring is available for hydrogen bonding, whilst in the second series, the indole NH group has been converted to NMe. Direct comparison of the emission wavelengths of analogous NH and NMe derivatives indicates the importance of the Kamlet-Taft solvent beta3 parameter, which reflects the ability of the solvent to accept a hydrogen bond from the NH group, an effect not possible for the NMe series of dendrimers. For the NH dendrimers, the attachment of a dendritic shell to the tryptophan subunit leads to a red shift in emission wavelength. This dendritic effect only operates in non-hydrogen-bonding solvents. For the NMe dendrimers, however, the attachment of a dendritic shell has no effect on the emission spectra of the indole ring. This proves the importance of hydrogen bonding between the branched shell and the indole NH group in causing the dendritic effect. This is the first time a dendritic effect has been unambiguously assigned to individual hydrogen-bonding interactions and indicates that such intramolecular interactions are important in dendrimers, just as they are in proteins. Furthermore, this paper sheds light on the use of tryptophan residues as a probe of the microenvironment within proteins--in particular, it stresses the importance of hydrogen bonds formed by the indole NH group.

Blood-borne and sexual transmission of human herpesvirus 8 in women with or at risk for human immunodeficiency virus infection

BACKGROUND

Human herpesvirus 8 (HHV-8), the causal agent of Kaposi's sarcoma, is transmitted sexually among homosexual men, but little is known of its transmission among women. Although HHV-8 has been detected in blood, there has been no clear evidence of blood-borne transmission.

METHODS

We identified risk factors for HHV-8 infection in 1295 women in Baltimore, Detroit, New York, and Providence, Rhode Island, who reported high-risk sexual behavior or drug use. HHV-8 serologic studies were performed with two enzyme-linked immunosorbent assays.

RESULTS

In univariate analyses, HHV-8 was associated with black race, Hispanic ethnic background, a lower level of education, and infection with syphilis, the human immunodeficiency virus (HIV), hepatitis B virus (HBV), or hepatitis C virus (HCV). The risk of seropositivity for HHV-8 increased with the frequency of injection-drug use (P<0.001); HHV-8 seroprevalence among the women who used drugs daily was three times that among women who never injected drugs. Among the women with a low risk of sexual transmission, HHV-8 seroprevalence was 0 percent in those who had never injected drugs and 36 percent in those who had injected drugs (P<0.001). However, injection-drug use was linked less strongly to HHV-8 infection than to infection with HBV or HCV. In a multivariate analysis, independent predictors of HHV-8 seropositivity included HIV infection (odds ratio, 1.6; 95 percent confidence interval, 1.1 to 2.2), syphilis infection (odds ratio, 1.8; 95 percent confidence interval, 1.1 to 2.8), and daily injection-drug use (odds ratio, 3.2; 95 percent confidence interval, 1.4 to 7.6).

CONCLUSIONS

Both injection-drug use and correlates of sexual activity were risk factors for HHV-8 infection in the women studied. The independent association of HHV-8 infection with injection-drug use suggests that HHV-8 is transmitted through needle sharing, albeit less efficiently than HBV, HCV, or HIV.

Neurocognitive performance enhanced by highly active antiretroviral therapy in HIV-infected women

OBJECTIVE

To determine whether highly active retroviral therapy (HAART) is associated with better neurocognitive outcome over time among HIV-infected women with severely impaired immune function.

METHODS

A semiannual neurocognitive examination on four tasks was administered: Color Trail Making, Controlled Oral Word Association, Grooved Pegboard and Four-Word Learning. This protocol was initiated in the HIV Epidemiological Research study (HERS) study when a woman's CD4 cell count fell to < 100 x 10(6) cells/l. Immune function (CD4), viral load status and depression severity (CESD) were also assessed semi-annually, along with an interview to determine medication intake and illicit drug use.

RESULTS

HAART was not available to any participant at the time of enrollment (baseline), while 44% reported taking HAART at their most recent visit (mean duration of HAART 36.3 +/- 12.6 months). HAART-treated women had improved neurocognitive performance compared with those not treated with HAART. Women taking HAART for 18 months or more showed the strongest neurocognitive performance with improved verbal fluency, psychomotor and executive functions. These functions worsened among women not taking HAART. Substance abuse status, severity of depressive symptoms, age and educational level did not influence the HAART treatment effects on neurocognitive performance. Neurocognitive improvements were strongly associated with the magnitude of CD4 cell count increases.

CONCLUSIONS

HAART appeared to produce beneficial effect on neurocognitive functioning in HIV-infected women with severely impaired immune systems. Benefits were greatest for women who reported receiving HAART for more than 18 months.

Assessing clusters and motifs from gene expression data

Large-scale gene expression studies and genomic sequencing projects are providing vast amounts of information that can be used to identify or predict cellular regulatory processes. Genes can be clustered on the basis of the similarity of their expression profiles or function and these clusters are likely to contain genes that are regulated by the same transcription factors. Searches for cis-regulatory elements can then be undertaken in the noncoding regions of the clustered genes. However, it is necessary to assess the efficiency of both the gene clustering and the postulated regulatory motifs, as there are many difficulties associated with clustering and determining the functional relevance of matches to sequence motifs. We have developed a method to assess the potential functional significance of clusters and motifs based on the probability of finding a certain number of matches to a motif in all of the gene clusters. To avoid problems with threshold scores for a match, the top matches to a motif are taken in several sample sizes. Genes from a sample are then counted by the cluster in which they appear. The probability of observing these counts by chance is calculated using the hypergeometric distribution. Because of the multiple sample sizes, strong and weak matching motifs can be detected and refined and significant matches to motifs across cluster boundaries are observed as all clusters are considered. By applying this method to many motifs and to a cluster set of yeast genes, we detected a similarity between Swi Five Factor and forkhead proteins and suggest that the currently unidentified Swi Five Factor is one of the yeast forkhead proteins.

Electrochemically controlled hydrogen bonding. o-Quinones as simple redox-dependent receptors for arylureas

9,10-Phenanthrenequinone and acenaphthenequinone are shown to act as simple redox-dependent receptors toward aromatic ureas in CH(2)Cl(2) and DMF. Reduction of the o-quinones to their radical anions greatly increases the strength of hydrogen bonding between the quinone carbonyl oxygens and the urea N-hydrogens. This is detected by large positive shifts in the redox potential of the quinones with no change in electrochemical reversibility upon addition of urea guests. Cyclic voltammetric studies with a variety of possible guests show that the effect is quite selective. Only guests with two strong hydrogen donors, such as O-H bonds or amide N-H bonds, that are capable of simultaneously interacting with both carbonyl oxygens give large shifts in the redox potential of the quinones. The electronic character and conformational preference of the guest are also shown to significantly affect the magnitude of the observed potential shift. In the presence of strong proton donors the electrochemistry of the quinone becomes irreversible indicating that proton transfer has taken place. Experiments with compounds of different acidity show that the pK(a) of the protonated quinone radical is about 15 on the DMSO scale, >4 pK(a) units smaller than that of 1,3-diphenylurea. This is further proof that hydrogen bonding and not proton transfer is responsible for the large potential shifts observed with this and similar guests.

Efficacy of postexposure prophylaxis after intravaginal exposure of pig-tailed macaques to a human-derived retrovirus (human immunodeficiency virus type 2)

Postexposure prophylaxis (PEP) after intravaginal exposure to human immunodeficiency virus (HIV) was investigated using the HIV type 2 (HIV-2)/pig-tailed macaque transmission model. PEP for 28 days with the reverse transcriptase inhibitor (R)-9-(2-phosphonylmethoxypropyl)adenine (PMPA; tenofovir) was initiated 12 to 72 h following HIV-2 exposure. Systemic infection was not evident in the 12- and 36-h groups, as defined by plasma viremia, cell-associated provirus, antibody responses, and lymph node virus. Breakthrough infection in the 72-h group was detected at week 16 post-virus exposure. These results demonstrate for the first time using a vaginal transmission model that early intervention after high-risk sexual exposures may prevent infection.

MRI of the wrist

In the past, the diagnostic imaging algorithm for evaluating the painful wrist included initial plain radiographic examination followed by arthrography, tomography, bone scintigraphy, or computed tomography. In recent years, magnetic resonance imaging (MRI) has been proven efficacious for diagnosing a number of maladies of the bones, ligaments, and soft tissues. MRI can be of aid in evaluation of carpal instability, disorders of the triangular fibrocartilage, ulnar impaction syndrome, distal radioulnar joint (DRUJ) instability, fracture, avascular necrosis (AVN), tendinopathy, nerve entrapment syndromes, synovial abnormalities, and soft tissue masses.

Superior cantholysis for zygomatic fracture repair

OBJECTIVE

To determine if performing a superior cantholysis eases the surgical exposure, reduction, and rigid fixation of the zygomaticofrontal suture in the open repair of zygomatic complex (ZMC) fractures.

PATIENTS AND METHODS

Fifteen superior cantholysis procedures were used in 14 patients who presented with ZMC fractures requiring open reduction and internal fixation. Follow-up ranged from 6 to 18 months. Collected data included patient demographics, cause of fracture, fracture classification, associated facial injuries, methods of fracture exposure and reduction, type and location of fixation, procedure-related complications, and postoperative outcome, including adequacy of fracture reduction.

RESULTS

Superior cantholysis opens a direct surgical route to the zygomaticofrontal suture for exposure, reduction, and rigid fixation. It also expedites exposure and assessment of the sphenozygomatic suture. No postreduction ZMC malunions or malpositions occurred during the study. There were 4 complications, none of which could be attributed to superior cantholysis. The complications related primarily to the transconjunctival and lateral canthotomy incisions.

CONCLUSIONS

Superior cantholysis eases the surgical exposure, reduction, and rigid fixation of the zygomaticofrontal suture in the open repair of ZMC fractures. The superior cantholysis added no morbidity in open ZMC fracture repair, and it simplified exposure of the lateral orbital rim, without the need for overzealous tissue retraction.

HIV/AIDS among African Americans: progress or progression?

OBJECTIVES

To review data on the extent of HIV infection and associated risk behaviors, the occurrence of AIDS, and HIV-related mortality in African Americans and to suggest what can be done to reduce HIV exposure and infection in this population.

DESIGN/METHODS

Review of epidemiologic, published, multisite data on HIV infection in, and related behaviors of, African Americans.

RESULTS

On every epidemiologic measure in common use, African Americans, compared with the four other federally recognized racial/ethnic groups, have the most severe epidemic. The trend data show continuing growth in the African American epidemic despite the availability of effective behavioral interventions and biomedical treatments. Few published intervention studies with African American populations have been adequately evaluated; nor have they focused proportionately on men who have sex with men, a group in the African American community with continuing high rates of infection.

CONCLUSIONS

Rates of HIV transmission and disease among African Americans are high, disproportionate, and are not declining as significantly in response to effective interventions as they are among whites. Attention is urgently needed to increase our understanding of risk behaviors, social networks, and specific factors in the African American community that can be altered to reduce HIV infection. Macroenvironmental factors--poverty, social class, racism--need to be studied to suggest possible intervention components to reduce rates of HIV transmission and to increase the use of therapies that are more effectively slowing disease progression and lowering death rates among whites.

Backbone dynamics measurements on leukemia inhibitory factor, a rigid four-helical bundle cytokine

The backbone dynamics of the four-helical bundle cytokine leukemia inhibitory factor (LIF) have been investigated using 15N NMR relaxation and amide proton exchange measurements on a murine-human chimera, MH35-LIF. For rapid backbone motions (on a time scale of 10 ps to 100 ns), as probed by 15N relaxation measurements, the dynamics parameters were calculated using the model-free formalism incorporating the model selection approach. The principal components of the inertia tensor of MH35-LIF, as calculated from its NMR structure, were 1:0.98:0.38. The global rotational motion of the molecule was, therefore, assumed to be axially symmetric in the analysis of its relaxation data. This yielded a diffusion anisotropy D(parallel)/D(perpendicular) of 1.31 and an effective correlation time (4D(perpendicular) + 2D(parallel))(-1) of 8.9 ns. The average values of the order parameters (S2) for the four helices, the long interhelical loops, and the N-terminus were 0.91, 0.84, and 0.65, respectively, indicating that LIF is fairly rigid in solution, except at the N-terminus. The S2 values for the long interhelical loops of MH35-LIF were higher than those of their counterparts in short-chain members of the four-helical bundle cytokine family. Residues involved in LIF receptor binding showed no consistent pattern of backbone mobilities, with S2 values ranging from 0.71 to 0.95, but residues contributing to receptor binding site III had relatively lower S2 values, implying higher amplitude motions than for the backbone of sites I and II. In the relatively slow motion regime, backbone amide exchange measurements showed that a number of amides from the helical bundle exchanged extremely slowly, persisting for several months in 2H2O at 37 degrees C. Evidence for local unfolding was considered, and correlations among various structure-related parameters and the backbone amide exchange rates were examined. Both sets of data concur in showing that LIF is one of the most rigid four-helical bundle cytokines.

Sensitivity enhancement of HCACO by using an HMQC magnetization transfer scheme

Previous theoretical calculations have demonstrated that the multiquantum relaxation rate of (1)H(alpha)-(13)C(alpha)(R(MQ)) is, on average, 1.3 +/- 0.4 or 1.7 +/- 0.6 times slower than the single-quantum relaxation rate of (13)C(alpha)(R(C)) for a sample with or without, respectively, amide protons. By taking advantage of this fact and by using the PEP sensitivity enhancement scheme, an HMQC version of the HCACO experiment has been developed. We demonstrate that this new experiment is 23 and 55% more sensitive than the original HSQC version of the HCACO experiment, at constant times of 7 and 27 ms, respectively, for a sample of the BC domain of the ciliary neurotrophic factor receptor protein dissolved in D(2)O at 20 degrees C.

The effect of pH on the structure, binding and model membrane lysis by cecropin B and analogs

Cecropins are a group of anti-bacterial, cationic peptides that have an amphipathic N-terminal segment, and a largely hydrophobic C-terminal segment and normally form a helix-hinge-helix structure. In this study, the ability of cecropin B (CB) and two analogs to lyse phospholipid bilayers, which have two levels of anionic content, has been examined by dye-leakage measurements over the pH range 2. 0-12.0. The two analogs differ from the natural peptide by having either two amphipathic segments (CB1) or two hydrophobic segments (CB3). All these peptides (except CB3 on low anionic content bilayers where it is not active) have maximal lytic activity on both types of bilayers at high pH. However, the pattern of secondary structure formation on these bilayers by the peptides, as measured by circular dichroism (CD), and the pattern of their ability to bind lipid monolayers, as measured using a biosensor, do not directly correlate with the pattern of their lytic ability. CB and CB1 with low anionic content bilayers have secondary structures as measured by CD with a similar pattern to membrane lysis, but binding is maximal near neutral, not high, pH. CB3 has some secondary structures on low anionic content bilayers at low pH and this becomes maximal over the basic range, but CB3 neither binds to nor lyses with these lipid layers. On high anionic content lipid layers, all peptides show high levels of secondary structures over most of the pH range and maximal binding at neutral pH (except for CB3, which does not bind). All three peptides lyse with high anionic content bilayers, but show no activity at neutral pH and reach maximal activity at very high pH. This work shows that pH is a major factor in the capability of antibacterial peptides to lyse with liposomes and that secondary structure and binding ability may not be the main determinants.

Effects of vasoactive topical agents on the survival of dorsal skin flaps in rats

OBJECTIVE

To evaluate 3 vasoactive topical agents regarding their ability to improve the survival of random skin flaps in rats.

METHOD

Thirty-five adult Sprague-Dawley rats had a single 9 x 2 cm random skin flap raised with topical application of a white petroleum ointment (control group), prostaglandin E2, minoxidil, or nitroglycerin to the flap. The effect of the agents on the viability of the flaps was evaluated.

RESULTS

The control group had an average survival area of 60.8% +/- 7.9%. The nitroglycerin and minoxidil groups were not significantly different, with an average area of survival of 60.1% +/- 8.1% and 63.3% +/- 4.7%, respectively. The prostaglandin E2 group had average area of survival of 74.2% +/- 10.5% (P = 0.002).

CONCLUSION

Prostaglandin E2 demonstrated a significant increase in flap survival. Nitroglycerin ointment and minoxidil had no beneficial effects when compared with control.

Interaction of granulocyte colony-stimulating factor (G-CSF) with its receptor. Evidence that Glu19 of G-CSF interacts with Arg288 of the receptor

Granulocyte colony-stimulating factor (G-CSF) forms a tetrameric complex with its receptor, comprising two G-CSF and two receptor molecules. The structure of the complex is unknown, and it is unclear whether there are one or two binding sites on G-CSF and the receptor. The immunoglobulin-like domain and the cytokine receptor homologous module of the receptor are involved in G-CSF binding, and Arg288 in the cytokine receptor homologous module is particularly important. To identify residues in G-CSF that interact with Arg288, selected charged residues in G-CSF were mutated to Ala. To clarify whether there are two binding sites, a chimeric receptor was created in which the Ig domain was replaced with that of the related receptor gp130. This chimera bound G-CSF but could not transduce a signal, consistent with failure of dimerization and loss of one binding site. The G-CSF mutants had reduced mitogenic activity on cells expressing wild-type receptor. When tested with the chimeric receptor, all G-CSF mutants except one (E46A) showed reduced binding, suggesting that Glu46 is important for interaction with the Ig domain. On cells expressing R288A receptor, all the G-CSF mutants except E19A showed reduced mitogenic activity, indicating that Glu19 of G-CSF interacts with Arg288 of the receptor.

Orlistat, a lipase inhibitor, for weight maintenance after conventional dieting: a 1-y study

BACKGROUND

Long-term maintenance of weight loss remains a therapeutic challenge in obesity treatment.

OBJECTIVE

This multicenter, double-blind, placebo-controlled study was designed to test the hypothesis that orlistat, a gastrointestinal lipase inhibitor, is significantly more effective than a placebo in preventing weight regain.

DESIGN

Obese subjects who lost > or = 8% of their initial body weight during a 6-mo lead-in of a prescribed hypoenergetic diet (4180-kJ/d deficit) with no adjunctive pharmacotherapy were randomly assigned to receive placebo, 30 mg orlistat, 60 mg orlistat, or 120 mg orlistat 3 times daily for 1 y in combination with a maintenance diet to help prevent weight regain. Of 1313 recruited subjects [body mass index (in kg/m2): 28-43], 729 subjects lost > or =8% of their initial body weight during the 6-mo weight-loss lead-in period and were enrolled in the double-blind phase.

RESULTS

After 1 y, subjects treated with 120 mg orlistat 3 times daily regained less weight than did placebo-treated subjects (32.8 +/- 4.5% compared with 58.7 +/- 5.8% regain of lost weight; P < 0.001). Moreover, more subjects in the 120-mg orlistat group than in the placebo group regained < or = 25% of lost weight (47.5% of subjects compared with 29.9%). In addition, orlistat treatment (120 mg 3 times daily) was associated with significantly greater reductions in total and LDL-cholesterol concentrations than was placebo (P < 0.001).

CONCLUSION

The use of orlistat during periods of attempted weight maintenance minimizes weight readjustment and facilitates long-term improvement in obesity-related disease risk factors.

Use of postoperative chest x-ray after elective adult tracheotomy

Surgeons have been creating tracheotomies since at least 124 AD, when first reported by Asclepiades (Price HC, Postma DS. Ear Nose Throat J 1983;62:44-59). Intraoperative and postoperative complications specifically associated with this procedure have been well established. The incidence of pneumothorax ranges from 0% to 17%, depending on the age group studied. To evaluate this complication, it is generally accepted that a postoperative chest film should routinely be obtained after a tracheotomy in adult patients. In adult nonemergent tracheotomies, the routine use of a postoperative chest film has a low yield for detecting a pneumothorax in patients without clinical findings of pneumothorax. To evaluate the use of postoperative chest x-ray in adult tracheotomy patients, a retrospective review of tracheotomies performed at the Boston Medical Center from January 1994 to June 1996 was undertaken. Data examined consisted of age, sex, surgical indication, urgency, operating service, intraoperative and postoperative complications, difficulty of procedure, anesthetic technique, findings on postoperative chest film, signs and symptoms of pneumothorax, and specific treatment of pneumothorax if present. In total, 250 patients were identified. The main indication for tracheostomy in this study was ventilator dependence, accounting for 77% of the procedures. A complication rate of 11.6% was encountered, with no deaths. Postoperative hemorrhage was the most common complication (3.6%). Pneumothorax was documented by chest x-ray in 3 (1.2%) patients, 1 of whom had bilateral pneumothoraces. The most common symptom of a pneumothorax was tachycardia, with 8.8% of the patients exhibiting at least 1 episode. Of the 3 cases of pneumothorax in this study, only 1 was clinically relevant and required treatment. Furthermore, the clinical signs and symptoms in this patient clearly supported the diagnosis of pneumothorax before a postoperative chest film was obtained. Thus postoperative chest radiographs did not change the treatment or outcome of any of the patients undergoing a tracheotomy. This suggests that postoperative chest x-ray after adult tracheotomy is not required in routine cases. Chest radiographs should be obtained after emergent procedures, after difficult procedures, or in patients exhibiting signs or symptoms of pneumothorax.

Comparison of clinical manifestations of HIV infection among women by risk group, CD4+ cell count, and HIV-1 plasma viral load. HER Study Group. HIV Epidemiology Research

OBJECTIVES

To compare the prevalence of HIV-related symptoms, physical examination findings, and hematologic variables among women whose risk for HIV is injection drug use since 1985 as opposed to sexual contact and to evaluate the influence of HIV plasma viral load and CD4+ cell count on clinical manifestations according to risk.

METHODS

Participants of the HIV Epidemiology Research Study (HERS; a multicenter, prospective, controlled study of HIV infection in women) were administered a risk behavior and symptom interview, underwent a physical examination, and received hematologic testing, including CD4+ cell counts done on study entry. Plasma HIV-1 viral loads were performed on stored frozen plasma using an ultrasensitive branched-DNA (b-DNA) signal amplification assay. CD4+ counts were categorized as <200 cells/microl, 200 to 499 cells/microl, or > or =500 cells/microl, and HIV viral loads were characterized in tertiles.

RESULTS

Cross-sectional analysis was conducted on data available for 724 HIV-infected women: 387 had a history of intravenous drug use and 337 were infected through heterosexual contact. The median CD4+ count was 376 cells/microl; the median HIV-1 viral load was 1135 copies/ml; and 281 of 724 HIV-infected women (38.8%) had an undetectable HIV-1 viral load. In analyses adjusting for CD4+ cell level alone and for plasma viral load combined with CD4+ cell level, injection drug users (IDUs) were more likely than those infected through heterosexual contact to report a recent episode of memory loss and weight loss, but less likely to have recent episodes of genital herpes; to have enlarged livers and a body mass index (BMI) <24, and to have hematocrit levels <34% and platelet counts <150,000 cells/ml. After adjustment for CD4+ cell level and risk group, high and medium HIV-1 plasma viral load levels were associated with the presence of oral hairy leukoplakia on examination, and only the highest level of plasma viral load was associated with recent histories of fever and thrush, oral hairy leukoplakia, pseudomembranous candidiasis, and BMI <24 on examination, and hematocrit <34%.

CONCLUSIONS

In this cohort of women, the distribution of HIV-1 plasma viral load was lower than that previously reported in populations of HIV-infected men. This study also shows some differences in frequency of signs, symptoms, and laboratory values between risk groups of HIV-infected women, but these results may be due to effects of injection drug use rather than HIV infection. Signs and symptoms identified as associated with increasing levels of viral load that were not different across risk groups suggest more direct association of these findings with HIV infection.

Microscopic observations of the different morphological changes caused by anti-bacterial peptides on Klebsiella pneumoniae and HL-60 leukemia cells

Natural anti-bacterial peptides cecropin B (CB) and its analogs cecropin B-1 (CB-1), cecropin B-2 (CB-2) and cecropin B-3 (CB-3) were prepared. The different characteristics of these peptides, with amphipathic/hydrophobic alpha-helices for CB, amphipathic/amphipathic alpha-helices for CB-1/CB-2, and hydrophobic/hydrophobic alpha-helices for CB-3, were used to study the morphological changes in the bacterial cell, Klebsiella pneumoniae and the leukemia cancer cell, HL-60, by scanning and transmission electron microscopies. The natural and analog peptides have comparable secondary structures as shown by circular dichroism measurements. This indicates that the potency of the peptides on cell membranes is dependent of the helical characteristics rather than the helical strength. The microscopic results show that the morphological changes of the cells treated with CB are distinguishably different from those treated with CB-1/CB-2, which are designed to have enhanced anti-cancer properties by having an extra amphipathic alpha-helix. The morphological differences may be due to their different modes of action on the cell membranes resulting in the different potencies with lower lethal concentration and higher concentration of 50% inhibition (IC50) of CB on bacterium and cancer cell, respectively, as compared with CB-1/:CB-2 (Chen et al. 1997. Biochim. Biophys. Acta 1336, 171-179). In contrast, CB-3 has little effect on either the bacterium or the cancer cell. These results provide microscopic evidence that different killing pathways are involved with the peptides.

Mucosal candidal colonization and candidiasis in women with or at risk for human immunodeficiency virus infection. HIV Epidemiology Research Study (HERS) Group

The epidemiology of mucosal candidal colonization and candidiasis was studied in a multicenter cohort of 871 human immunodeficiency virus (HIV)-seropositive and 439 demographically and behaviorally similar HIV-seronegative women. Cross-sectional analyses at baseline revealed that oropharyngeal colonization with Candida species was more prevalent among seropositive women and among women reporting recent cigarette smoking and injection drug use. Oropharyngeal candidiasis was also more prevalent among seropositive women. Both oropharyngeal colonization and candidiasis were significantly associated with a lower median CD4 lymphocyte count among seropositive women. Vaginal candidal colonization was more prevalent among seropositive women and among those reporting recent injection drug use and current insulin or oral antihyperglycemic therapy. Vaginal candidiasis was equally likely to be diagnosed in seropositive and seronegative women and was not significantly related to recent sexual contact. Neither vaginal colonization nor candidiasis was significantly related to a lower median CD4 lymphocyte count among seropositive women. Baseline evaluation indicated differences in the epidemiology of oropharyngeal and vaginal candidal colonization and candidiasis in HIV-seropositive women and suggested possible variation in pathogenesis of candidal infection at these two mucosal sites.

The dependence of membrane permeability by the antibacterial peptide cecropin B and its analogs, CB-1 and CB-3, on liposomes of different composition

A natural antibacterial peptide, cecropin B (CB), and designed analogs, CB-1 and CB-3, were synthesized. The three peptides have different structural characteristics, with CB having one hydrophobic and one amphipathic alpha-helix, CB-1 having two amphipathic alpha-helices, and CB-3 having two hydrophobic alpha-helices. These differences were used as the rationale for a study of their efficacy in breaking liposomes with different combinations of phosphatidic acid and phosphatidylcholine. Biosensor binding measurements and encapsulating dye leakage studies showed that the higher binding affinity of CB and CB-1 to the polar heads of lipids is not necessary for the peptides to be more effective at lysing lipid bilayers, especially when liposomes have a higher phosphatidic acid content. Kinetic studies, by intrinsic and extrinsic fluorescence stopped-flow measurements, revealed two transitional steps in liposome breakage by CB and CB-1, although only one kinetic step was found for CB-3. Circular dichroism stopped-flow measurements, monitoring the formation of secondary structure in the peptides, found one kinetic step for the interaction of all of the peptides with the liposomes. Also, the alpha-helical motif of the peptides was maintained after interacting with the liposomes. Based on these results, the mechanisms of liposome lysis by CB, CB-1, and CB-3 are discussed.

The immunoglobulin-like module of gp130 is required for signaling by interleukin-6, but not by leukemia inhibitory factor

The transmembrane protein gp130 is a shared component of the receptor complexes for the interleukin-6 (IL-6)-type cytokines, which include IL-6, leukemia inhibitory factor (LIF) and oncostatin M (OSM). In addition to its role in the generation of high affinity receptors, gp130 is required for signal transduction by these cytokines. In the present study we have examined the role of the N-terminal located, extracellular immunoglobulin (Ig)-like module of gp130 in signal transduction by IL-6 and LIF. We have expressed wild-type human gp130 or three mutants in murine myeloid M1-UR21 cells that lack functional endogenous gp130 but express the IL-6 receptor (IL-6R) and the LIF receptor (LIFR). By measuring cellular responses, such as morphological changes upon differentiation, soft agar colony formation, and induction of tyrosine phosphorylation of the signal transducer and activator of transcription, STAT3, we show that signaling by IL-6, but not LIF, is significantly reduced by mutations in the Ig-like module of gp130. However, the binding of 125I-labeled IL-6 or LIF is not affected by these mutations. We also present evidence that the Ig-like module forms part of the epitope of an anti-gp130 monoclonal antibody that neutralizes the bioactivity of IL-6, but not of LIF or OSM. The data suggest that gp130-activation by IL-6 and LIF requires different regions of gp130, that the Ig-like module of gp130 may be required for IL-6-induced gp130 dimerization, and that the stoichiometry of the high affinity IL-6 receptor-complex differs from those of the receptor-complexes for LIF and OSM.

A major component approach to presenting consensus sequences

MOTIVATION

Summarizing and displaying the information contained in a set of aligned sequences is an important aid to identifying patterns within the sequences. A variety of forms of consensus sequences have been used previously to provide this information. However, these methods can cause a loss of information or introduce ambiguities into the consensus sequence, and some graphical approaches may become difficult to interpret due to visual distortion.

RESULTS

We have developed a method to present a more precise and graphically clear view of a consensus sequence by using an approach based on defining the major components at each position in a sequence set. The major components are given in an ordered list and their frequencies are shown as histograms which can be colour coded to reflect conservative groupings. Minor components, a one-line character-based consensus sequence and information statistics can also be presented. As well as identifying the dominant sources of variation and conservation in the sequence set, the method also enables similarities and differences between subgroups of a sequence set to be readily assessed. AVAILIABILITY: On request from the authors.

CONTACT

bcsmith@usthk.ust.hk, hxue@usthk. ust.hk

Anti-BSA antibodies do not cross-react with the 69-kDa islet cell autoantigen ICA69

In contrast to several previously published reports, we demonstrate by a variety of antibody assays that bovine serum albumin (BSA) is not antigenically cross-reactive with the 69-kDa islet cell autoantigen (ICA69). Fast protein liquid chromatography purified BSA and highly purified recombinant human ICA69 were used to establish sensitive Western blot and ELISA assays in order to detect antibodies against these two proteins. The assays excluded BSA or powdered milk as blocking agents, since these would interfere with antibody binding. A panel of sera from diabetic individuals, first degree relatives, and normal controls showed that the majority (approximately 70%) of individuals from each group had antibodies against ICA69 as assayed by Western blots, whereas considerably fewer (approximately 13%) had anti-BSA antibodies on Western blots, and individuals with antibodies to both proteins occurred only rarely (2-3%). To explore this issue further we immunized a total of 16 individual rats, representing four different strains (bio-breeding diabetes resistant and diabetes prone, Wistar-Furth, and Sprague-Dawley), with either BSA (n = 2 of each strain) or with recombinant ICA69 (n = 2 of each strain), and for each animal pre- and postimmune antibody titres against BSA and against ICA69 were assayed separately by enzyme-linked immunoabsorbent assay. In rats immunized with BSA, anti-BSA titres increased about 100,000-fold over preimmune levels, whereas anti-ICA69 reactive antibodies were unchanged over preimmune levels. Similarly, in rats immunized with ICA69, anti-ICA69 titres rose about 100,000-fold over preimmune levels, whereas anti-BSA antibodies were unchanged over preimmune levels. Thus we find no evidence for the existence of antibody cross-reactivity between ICA69 and BSA, either in humans or in immunized rats. When our rat anti-BSA antisera were used to probe Western blots made from rat islets isolated in the strict absence of fetal calf serum, we were unable to detect a 69-kDa band, even when the islets were preincubated with gamma-interferon, a treatment which has been reported to induce the BSA cross-reactive islet antigen. We conclude that BSA is not antigenically cross-reactive with ICA69 at the antibody level, and it is highly unlikely that BSA is antigenically cross-reactive with some other 69 kD islet cell antigen.

Prediction of nocturnal plasma melatonin from morning urinary measures

A growing literature indicates that blood levels of the hormone melatonin may have important implications for human health and well-being. Melatonin is synthesized and released into the general circulation at night, however, and it is seldom feasible to draw blood samples at night in epidemiological studies. There is some evidence that levels of urinary melatonin and of 6-sulfatoxymelatonin (aMT6s), the major metabolite of melatonin, accurately reflect nocturnal plasma melatonin. If this is the case, urinary assays could be powerful tools for epidemiological studies. A laboratory-based study was performed to examine the relationships between nocturnal plasma melatonin, morning urinary melatonin, and morning urinary aMT6s levels in 78 men. The relationship between total nocturnal plasma melatonin and both urinary aMT6s corrected for creatinine and urinary melatonin is significant. Combining the two urinary measures accounts for 72% of the variance in total plasma melatonin. Peak nocturnal plasma melatonin also was significantly related to urinary melatonin and to aMT6s. The urinary measures show good sensitivity and specificity in identifying individual differences in nocturnal plasma melatonin levels. These results support the inclusion of morning urine samples to assess the contribution of the hormone melatonin in occupational or residential studies involving healthy, young men.

LIF receptor-gp130 interaction investigated by homology modeling: implications for LIF binding

Leukemia inhibitory factor (LIF), a member of the gp130 family of helical cytokines, is involved in the hemopoietic and neural systems. The LIF signal transducing complex contains two receptor molecules, the LIF receptor (LIFR) and gp130. The extracellular region of the LIFR is unique in that it includes three membrane-proximal fibronectin type III domains and two cytokine binding domains (CBDs) separated by an immunoglobulin-like domain. Although some mutagenesis data on LIF are available, it is not yet known which regions of LIFR or gp130 bind LIF. Nor is it known whether LIFR contacts gp130 in a manner similar to the growth hormone receptor dimer and, if so, through which of its CBDs. To attempt to elucidate these matters and to investigate the receptor complex, models of the CBDs of LIFR and the CBD of gp130 were constructed. Analyses of the electrostatic isopotential surfaces of the CBD models suggest that gp130 and the membrane-proximal CBD of LIFR hetero-dimerize and bind LIF through contacts similar to those seen in the growth hormone receptor dimer. This work further demonstrates the utility of electrostatic analyses of homology models and suggests a strategy for biochemical investigations of the LIF-receptor complex.

Measurement of exercise dependence in bodybuilders

OBJECTIVE

The purpose of this study was to explore exercise dependence in bodybuilders, and undertake preliminary validation of a measurement instrument.

EXPERIMENTAL DESIGN

A comparative analysis of self-report indices between groups.

PARTICIPANTS

Forty-seven bodybuilders, 31 individuals who weight trained for general fitness purposes and 24 weightlifters participated in the study.

MEASURES

Each subject completed the following: demographic information, bodybuilding-specific versions of the social identity and exclusivity scales of the Athletic Identity Measurement Scale, the physical strength and body attractiveness subscales of the Physical Self-Perception Profile, a short form of the Marlowe-Crowne Social Desirability Scale, and a 9-item Bodybuilding Dependence Scale.

RESULTS

Factor analysis on the BDS revealed 3 subscales (social dependency, training dependency and mastery) which accounted for 68.4% of the variance. Internal consistency was satisfactory for each subscale (Chronbach's alpha = 0.76, 0.75 and 0.78 respectively). The BDS social dependency and PSPP body attractiveness scores of the bodybuilders were higher than those of the weightlifters, whose scores were higher than those of the fitness trainers. The bodybuilders scored higher on both AIMS subscales than the other groups. The bodybuilders and weightlifters scored higher on PSPP physical strength than the fitness trainers. BDS social dependency correlated with both AIMS and both PSPP subscales, and BDS training dependency correlated with AIMS exclusivity. All three BDS subscales correlated with training frequency. Discriminant analysis found the combination of AIMS social identity, BDS social dependency and years training experience enabled correct classification of 92% of the respondents.

CONCLUSIONS

These results support the construct and concurrent validity of the BDS social dependency subscale, but do not wholly support the validity of the other two subscales.