Biomedical subjects

S L Bailey

Publications and source records attributed to S L Bailey.

At least 19 recordsLinked to original sources

PubMed2005

Strange-quark contributions to parity-violating asymmetries in the forward g0 electron-proton scattering experiment.

We have measured parity-violating asymmetries in elastic electron-proton scattering over the range of momentum transfers 0.12 < or =Q2 < or =1.0 GeV2. These asymmetries, arising from interference of the electromagnetic and neutral weak interactions, are sensitive to strange-quark contributions to the currents of the proton. The measurements were made at Jefferson Laboratory using a toroidal spectrometer to detect the recoiling protons from a liquid hydrogen target. The results indicate nonzero, Q2 dependent, strange-quark contributions and provide new information beyond that obtained in previous experiments.

Journal Article↗

PubMed2001

Injection-related risk behaviors in young urban and suburban injection drug users in Chicago (1997-1999).

We compared injection-related risk practices between urban and suburban injection drug users (IDUs) in a large cross-sectional sample of young IDUs. From 1997 to 1999, we recruited 700 active IDUs aged 18 to 30 years in Chicago and its suburbs. A suburban residence was reported by 38% of participants. Participants were interviewed at four urban locations and screened for HIV and hepatitis C virus antibodies. Receptive sharing of syringes and other paraphernalia by urban and suburban IDUs in the preceding 6 months was compared using univariable and multivariable models. Sharing injection paraphernalia in the total sample was high, with 50% of participants reporting receptive syringe sharing and 70% reporting sharing cotton, cookers, and/or rinse water. After adjusting for demographic characteristics, injection settings, frequency, and duration of injection as well as ease of acquiring new syringes, suburban IDUs were significantly more likely than urban IDUs to share syringes (adjusted odds ratio = 1.7; 95% confidence interval: 1.1-2.5); however, the likelihood of sharing cotton, cookers, or rinse water was roughly equal. Despite overall higher risk profiles among suburban IDUs, HIV and hepatitis C prevalence levels were significantly lower than among urban participants. Current high levels of injection risk behaviors in suburban groups represent a potential for rapid dissemination of infection.

Adolescent↗

PubMed2001

Circadian rhythmicity of cortisol and body temperature: morningness-eveningness effects.

The purpose of this study was to describe and compare the circadian rhythm of body temperature and cortisol, as well as self-reported clock times of sleep onset and offset on weekdays and weekends in 19 healthy adult "larks" (morning chronotypes) and "owls" (evening chronotypes), defined by the Home and Ostberg questionnaire. Day-active subjects entered the General Clinical Research Center, where blood was sampled every 2 h over 38 h for later analysis for cortisol concentration by enzyme immunoassay. Rectal body temperature was measured continuously. Lights were turned off at 22:30 for sleep and turned on at 06:00, when subjects were awakened. The acrophases (peak times) of the cortisol and temperature rhythms occurred 55 minutes (P < or = .05) and 68 minutes (P < .01), respectively, earlier in the morningness group. The amplitude of the cortisol rhythm was lower in the eveningness than in the morningness group (P = n.s.). Subject groups differed on all indices of habitual and preferred timing of sleep and work weekdays and weekends (P = .05-.001).

Adult↗

PubMed2001

The impact of nalmefene on side effects due to intrathecal morphine at cesarean section.

Nalmefene is a long-acting opioid antagonist that provides long-term relief from side effects of intrathecal morphine sulfate. A randomized, double-blind, placebo-controlled study was conducted to determine whether prophylactic nalmefene could decrease side effects of intrathecal morphine given during cesarean section, without affecting analgesia. Sixty parturients were given 0.25 mg of intrathecal morphine, 12.5 micrograms of fentanyl, and 11.25 to 15 mg of bupivacaine. A dose of 0.25 microgram/kg of nalmefene or placebo was given by intravenous piggyback immediately after delivery of the neonate. Nausea, vomiting, pruritus, and level of sedation were assessed for a 24-hour period using a 4-point ordinal scoring system. Pain was assessed by using a 0- to 10-point verbal analogue scale. A 5-point analgesic satisfaction survey also was completed. Subjects who received nalmefene required supplemental analgesia at a median of 6.00 hours after intrathecal morphine, compared with 14.12 hours in the placebo group (P = .037). No differences were found between the groups in the incidence of pruritus, nausea and vomiting, level of sedation, or analgesic satisfaction. We concluded that nalmefene at a dose of 0.25 microgram/kg does not decrease the incidence of side effects but increases the need for supplemental analgesics.

Adult↗

PubMed2000

Prevalence and incidence of HIV among out-of-treatment injecting drug users, Chicago 1994-1996.

OBJECTIVES: To assess HIV prevalence, incidence, and associated risk factors among IDUs in Chicago. METHODS: Seven hundred ninety-four street-recruited IDUs ranging in age from 18 to 50 years, who were not in drug treatment at study enrollment, were interviewed and tested for HIV at baseline and at two follow-ups scheduled 6 and 12 months after baseline. Questionnaires assessed respondents' demographic characteristics, medical and drug treatment histories, drug use, and sexual practices. RESULTS: HIV seroprevalence at baseline was 18%. Logistic regression identified the following determinants of prevalent HIV infection: Puerto Rican ethnicity, homosexual or bisexual self-identification, injecting for 4 or more years, and having smoked crack cocaine in the past 6 months. Follow-up data were collected from 584 (73.6%) participants. Mean duration of follow-up was 16.5 months, indicating that most subjects had follow-up intervals longer than the scheduled 6 and 12 months. Seven HIV seroconversions were observed in 632 person years of risk, yielding an incidence rate of 1.1 per 100 person years of risk. Injection for 3 or less years was positively associated with HIV seroconversion. CONCLUSIONS: The findings provide evidence of a decline in HIV incidence among IDUs, though newer injectors remain at elevated risk for infection.

Adolescent↗

PubMed2000

Evaluation of the welfare implications and efficacy of an ultrasonic 'deterrent' for cats.

The effect of the ultrasonic output of a commercial cat 'deterrent' was assessed by measuring the behaviour responses of 10 cats in a standard test arena. The cats were introduced to the arena approximately nine metres outside the stated range of efficacy of the product and small food piles were placed at one metre intervals towards the device. When the cats were released from the basket, their behaviour and location were recorded continuously. The behaviour of the cats with the device on and off was compared by using a general linear model and chi-squared analysis. Differences between individual cats were a significant factor in explaining the variance associated with the amount of 'relaxed behaviours' (P<0.001), and the time spent within the range of the device (P=0.006). The only significant behaviour changes recorded when the device was on, were an increased likelihood of ear flicking (P<0.001), less time spent actively exploring (P=0.043), and an increase in the amount of time spent in the reported ultrasonic range of the device (P=0.003).

Animal Welfare↗

PubMed2000

Sleep impairments in healthy seniors: roles of stress, cortisol, and interleukin-1 beta.

STUDY OBJECTIVES: Increased stress responsivity and a longer-lasting glucocorticoid increase are common findings in aging studies. Increased cortisol levels at the circadian nadir also accompany aging. We used 24 h free urine cortisol to assess these age changes in healthy seniors. We hypothesized that free cortisol levels would explain individual differences in age-related sleep impairments. DESIGN: The study compared sleep, cortisol, and sleep-cortisol correlations under baseline and "stress" conditions in men and women. SETTING: Subjects were studied in the General Clinical Research Center under baseline conditions and a mildly stressful procedure (24 h indwelling intravenous catheter placement). PARTICIPANTS: Eighty-eight healthy, nonobese subjects (60 women and 28 men) from a large study of successful aging participated in the study. Mean ages were 70.6 (+/-6.2) and 72.3 (+/-5.7) years for women and men, respectively. MEASUREMENTS: The 24 h urines were collected for cortisol assay (radioimmunoassay [RIA]); blood was sampled at three diurnal time points for assay (enzyme-linked immunosorbent assay [ELISA]) of interleukin-1 (IL-1) beta; sleep architecture and sleep electroencephalograms (EEGs) were analyzed (after an adaptation and screening night) on baseline and stress nights via polysomnography and EEG power spectral analysis. RESULTS: Healthy older women and men with higher levels of free cortisol (24 h urine level) under a mild stress condition had impaired sleep (lower sleep efficiency; fewer minutes of stages 2, 3, and 4 sleep; more EEG beta activity during non-rapid eye movement sleep [NREM] sleep). Similar results were obtained when stress reactivity measures were used (cortisol and sleep values adjusted for baseline values), but not when baseline values alone were used. Gender differences were apparent: Men had higher levels of free urine cortisol in both baseline and mild stress conditions. Cortisol and sleep correlated most strongly in men; cortisol stress response levels explained 36% of the variance in NREM sleep stress responses. In women, but not men, higher cortisol was also associated with earlier time of arising and less REM sleep. Higher cortisol response to stress was associated with increased circulating levels of IL-1beta, explaining 24% of the variance in a subset of women. CONCLUSION: These results indicate that free cortisol (as indexed by 24 h urine values) can index responses to mild stress in healthy senior adults, revealing functional correlations (impaired sleep, earlier times of arising, more EEG beta activity during sleep, more IL-1beta) and gender differences.

Adult↗

PubMed2000

Restorative effects of GDNF on striatal dopamine release in rats treated with neurotoxic doses of methamphetamine.

Repeated methamphetamine (METH) administration to animals can result in long-lasting decreases in striatal dopamine (DA) release and content. Glial cell line-derived neurotrophic factor (GDNF) has pronounced effects on dopaminergic systems in vivo, including neuroprotective effects against METH. The present experiments were designed to examine the ability of GDNF to reverse, or accelerate recovery from, METH-induced alterations in striatal DA release. Male Fischer-344 rats were administered METH (5 mg/kg, s.c.) or saline 4 times in one day at 2-hour intervals. Seven days later the animals were anesthetized and given a single injection of 10 microg GDNF, or vehicle, into the right striatum. Three weeks later microdialysis experiments were carried out in both the right and left striata to examine basal and evoked levels of DA and its metabolites 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA). In animals treated with METH followed by vehicle 7 days later, there were significant reductions in potassium- and amphetamine-evoked overflow of DA, and in basal levels of DOPAC and HVA, compared to control animals. In rats treated with METH followed 7 days later with GDNF, there were significant increases in potassium- and amphetamine-evoked overflow of DA on the right, GDNF-treated, side of the brain compared to the left side. Basal levels of DOPAC and HVA were also elevated on the GDNF-treated side of the brain. These results suggest that GDNF can accelerate recovery of dopaminergic release processes in the striatum of rats treated with neurotoxic doses of METH.

3,4-Dihydroxyphenylacetic Acid↗

PubMed2000

Levels of methyleugenol in a subset of adults in the general U.S. population as determined by high resolution mass spectrometry.

We developed a sensitive and accurate analytical method for quantifying methyleugenol (ME) in human serum. Our method uses a simple solid-phase extraction followed by a highly specific analysis using isotope dilution gas chromatography-high resolution mass spectrometry. Our method is very accurate; its limit of detection is 3.1 pg/g and its average coefficient of variation is 14% over a 200-pg/g range. We applied this method to measure serum ME concentrations in adults in the general U.S. population. ME was detected in 98% of our samples, with a mean ME concentration of 24 pg/g (range < 3.1-390 pg/g). Lipid adjustment of the data did not alter the distribution. Bivariate and multivariate analyses using selected demographic variables showed only marginal relationships between race/ethnicity and sex/fasting status with serum ME concentrations. Although no demographic variable was a good predictor of ME exposure or dose, our data indicate prevalent exposure of U.S. adults to ME. Detailed pharmacokinetic studies are required to determine the relationship between ME intake and human serum ME concentrations.

Adolescent↗

PubMed2000

Reliability and concurrent validity of DSM-IV subclinical symptom ratings for alcohol use disorders among adolescents.

BACKGROUND: The concurrent validity of subclinical ratings for psychiatric symptoms can help refine symptom definitions and threshold criteria. However, virtually no research has examined subclinical ratings for DSM-IV symptoms in psychiatric diagnostic interviews. This study examined the frequency, reliability, and concurrent validity of subclinical ratings for 11 symptoms of alcohol use disorders among adolescents. METHODS: Subjects were 239 male and 164 female adolescents ages 14 to 18 recruited from treatment and community sources. Symptoms and diagnoses were made with an adapted version of the Structured Clinical Interview for the DSM-IV. RESULTS: Subclinical ratings showed acceptable to high interrater reliability. The proportion of subclinical ratings tended to decrease with increasing levels of alcohol problems. For 10 of the 11 symptoms, subjects with subclinical ratings were distinguished from those with absent and/or those with present ratings. Subjects with subclinical ratings were often distinct from those with present ratings but less often distinct from those with absent ratings. CONCLUSIONS: For most of the DSM-IV alcohol use disorder symptoms, subclinical ratings appear to be reliable and valid and provide information beyond dichotomous symptom classifications for adolescents. Threshold criteria appear to be appropriate in many cases, but boundaries between absent and subclinical ratings are "fuzzy." Practical and research implications are discussed.

Adolescent↗

PubMed1999

Risky sexual behaviors among adolescents with alcohol use disorders.

Little is known about risky sexual activity among adolescents with alcohol use disorders. This study of 371 adolescent drinkers found that those with alcohol disorders were more likely than other drinkers to be sexually active, to have greater numbers of partners, and to initiate sexual activity at slightly younger ages. Independent of alcohol group, females were more likely than males to have unprotected sexual encounters.

Adolescent↗

PubMed1999

HIV-risk behaviors associated with homelessness characteristics in youth.

PURPOSE: To examine characteristics of youth homelessness associated with engaging in risk behaviors for human immunodeficiency virus (HIV). METHODS: The sample included 288 currently homeless or runaway Washington, DC youth aged 14-21 years. Measures were self-reported homelessness characteristics, unsafe sexual behavior, injection drug use, and background characteristics. Bivariate and multivariable analyses of the relationships between homelessness characteristics and HIV risk behaviors were conducted. RESULTS: Both male (n = 140) and female (n = 148) participants reported high rates of unsafe sexual behaviors, but low rates of injection drug use. HIV risk was significantly associated in bivariate analyses with severity of homelessness circumstances (i.e., spending the night in public place or with strangers, going hungry, and participating in the street economy), the duration of homelessness (i.e., greater number of episodes of homelessness, longer time length of current episode), and specific reasons for being homeless (i.e., thrown out). In addition, sexual victimization and older age were associated with increased HIV risk. In multivariable models, a smaller set of these homelessness characteristics remained significant independent correlates and explained a substantial amount of the variation in the HIV risk indices for both males and females. CONCLUSIONS: The results contribute to greater theoretical understanding of the characteristics of homelessness associated with increased risk of HIV infection within this vulnerable population of youth. The associations between homelessness characteristics and HIV risk suggest the need for HIV prevention efforts to focus directly on ameliorating the homelessness circumstances of youth.

Adolescent↗

PubMed1999

The measurement of problem drinking in young adulthood.

OBJECTIVE: Researchers and clinicians have been struggling for more than 20 years to define problem drinking. This study focuses on young adults and aims to examine the construct validity of three dimensions of problem drinking and to empirically determine appropriate cutpoints for problem drinking along these dimensions. METHOD: A stratified sample of 1,269 young adults who reported drinking alcohol in the year prior to 1995 was used in these analyses. Respondents were originally interviewed in 1985 in middle schools in a southeastern U.S. county. RESULTS: Symptoms of dependency and drunkenness were relatively common in this sample, but adverse consequences were rare. Results of analyses using the Chi-squared Automatic Interaction Detector (CHAID) and the SUrvey DAta ANalysis (SUDAAN) software suggest that drunkenness and adverse consequences are the most significant predictors of problems in other areas of life. Symptoms of dependency were significant only in interaction with drunkenness, although the analyses were limited to only lifetime measures of dependency. Appropriate cutpoints, based on these analyses, appear to be (1) drunk at least six times in the past year, (2) four or more lifetime symptoms of dependency and (3) one or perhaps two or more adverse consequences in the past year. CONCLUSIONS: Results suggest that frequency of drunkenness may be the single best indicator of problem drinking among young adults and that adverse consequences may indicate a more serious form of problem drinking than do symptoms of dependency. In addition, appropriate cutpoints on these dimensions for young adults appear to be similar to those that have been used in studies of adolescents. Further study of both adolescents and young adults is suggested.

Adolescent↗

PubMed1999

Social network characteristics associated with risky behaviors among runaway and homeless youth.

Runaway and homeless youth are at high risk for substance abuse and unsafe sexual behavior. Our study describes the personal social networks of these youth and examines network characteristics associated with risky behaviors. In 1995 and 1996, we interviewed a purposive sample of youth aged 14 through 21 who were living in Washington, DC and were identified on the streets or through shelters or other service agencies (N = 327). Although we found that most youth reported current social relationships, a significant minority (26%) did not. Youth without a social network were significantly more likely to report current illicit drug use, multiple sex partners, and survival sex than youth with a network. For youth with a network, the networks were small, strong in affective and supportive qualities, comprised primarily of friends, typically included an alcohol or illicit drug user, and usually were not a source of pressure for risky behaviors. Our results indicate that networks had risk-enhancing and risk-decreasing properties in that network characteristics were associated in both positive and negative directions with risky behaviors.

Adolescent↗

PubMed1998

Estrogen suppresses gastric motility response to thyrotropin-releasing hormone and stress in awake rats.

Symptoms associated with gastric motility alteration vary with stress and ovarian hormone status, most notably in women with irritable bowel syndrome. This study examines combined effects, comparing gastric motility during administration of a stress-related neuropeptide thyrotropin-releasing hormone (TRH) and restraint stress in conscious rats of varied ovarian hormone status. Adult rats were ovariectomized and implanted with estrogen, progesterone, or vehicle-releasing pellets. After 21 days, intracerebroventricular (i.c.) cannula and gastric tension transducer were implanted. After 25-27 days, motility was recorded during neuropeptide injection (TRH/saline i.c.) or restraint stress. TRH induced increased motility in all groups; the response varied with hormone group, and was least and briefest in estrogen-treated rats. Motility during restraint varied with hormone group; it was diminished in estrogen-treated but not other groups. Ovarian hormone status (estrogen) modifies gut response to TRH and restraint stress.

Animals↗

PubMed1998

Substance use and risky sexual behavior among homeless and runaway youth.

PURPOSE: To (a) characterize human immunodeficiency virus (HIV)-related risk behaviors of homeless youth; (b) determine whether substance use is associated with risky sexual behavior in this population; and, if so, (c) explore explanations for this relationship. METHODS: A purposive sample of 327 homeless youth (ages 14-21 years) in Washington, DC, were surveyed in 1995 and 1996. Survey items were adapted from items used in a national study of adult substance use and sexual behavior and measured global (lifetime) and event-specific (most recent sexual encounter) behaviors. RESULTS: Sexual activity with many partners, "survival" sex, and substance use were common. However, needle use was rare, and consistent condom use was evident in half the sample. Nearly all correlations between global measures of substance use and risky sex were statistically significant, but only a few of the event-specific correlations were significant. Marijuana use during the most recent sexual encounter was associated with nonuse of condoms, but this relationship disappeared in the multivariate model. However, crack use during the last encounter was associated with condom use; this relationship remained significant in the multivariate model. Lack of motivation to use condoms, longer histories of sexual activity and homelessness, symptoms of drug dependency, not discussing HIV risks with partner, and being female were also associated with nonuse of condoms. CONCLUSIONS: Homeless youth do use condoms, even within the context of substance use and casual sex. Results suggest that prevention and targeted intervention efforts have had some positive effect on this population, but young homeless women are in need of targeted prevention. Finally, additional research is needed to investigate the observed relationship between crack use and condom use in this sample.

Adolescent↗

PubMed1997

Characteristics of students who bring weapons to school.

PURPOSE: This study explores the relationships between social, demographic, and behavioral characteristics and self-reported carrying of a weapon to school among middle school students. The results provide a statistical profile of youth most likely to bring weapons to school and help to identify characteristics that are only spuriously related to this behavior. METHODS: Study respondents were part of an ongoing randomized evaluation of a school-based drug use prevention program in Illinois. Self-administered questionnaires were completed by 1,503 seventh and eighth graders in the spring of 1992. RESULTS: Fifteen percent of respondents brought some type of weapon to school in the past month. In a multivariate logistic regression model, being male, not living with both parents, not feeling close to parents, drinking heavily, participating in fights, damaging school property, and perceiving that at least a few other students brought weapons to school, were significantly associated with weapon carrying. Victimization and fear for safety in school were not significantly associated with weapon carrying in the multivariate model. CONCLUSIONS: Study results suggest that both the structure and the dynamics of the family play an important role in weapon carrying behavior. Weapon carrying also appears to cluster with other deviant behaviors. Furthermore, the findings suggest that weapons are not brought to school because of a heightened need for protection, but rather may be in response to normative influences in school.

Adolescent↗

PubMed1996

Products of aniline and triglycerides in oil samples associated with the toxic oil syndrome.

The toxic oil syndrome (TOS) was a devastating disease that occurred in Spain in 1981. The disease was associated with the consumption of aniline-denatured and refined rapeseed oil that had been illegally sold as olive oil. Many aniline-derived oil components have been identified in the oils; however, no etiological agent has ever been identified for this disease. We have continued the study of the TOS problem by applying new technology in the form of liquid chromatography interfaced via atmospheric pressure ionization with tandem mass spectrometry. Using liquid chromatography tandem mass spectrometry, we studied diluted TOS-associated oils by direct analysis without prior sample treatment. Using this technology, we found new classes of compounds that are associated with disease-related oils. The compounds that have been identified are esters and ester amides of 3-(N-phenylamino)-1,2-propanediol and are products of aniline and triglycerides. Because of the varied fatty acid (oleic acid, etc.) content of the oils, many variations of the above compounds are possible. We now report the identities of more than 20 compounds not previously identified. These compounds are strongly associated with oils that caused the toxic oil syndrome. We believe these compounds should be considered for future animal studies.

Anilides↗