UNVEILING THE SIGNIFICANCE OF DYNAMIC ARTERIAL ELASTANCE: AN INSIGHTFUL APPROACH TO ASSESSING ARTERIAL LOAD IN AN ENDOTOXIN SHOCK MODEL.

ABSTRACT: Background: The aim of this study was to investigate the relationship between dynamic arterial elastance (EaDyn) and the pulsatile and steady components of arterial load in an endotoxin shock model using a two-element Windkessel model and to describe the behavior of EaDyn in this model. Methods : Ten female Yorkshire pigs were administered lipopolysaccharide intravenously to induce endotoxin shock, while three female pigs served as the control group. Measurements of EaDyn (ratio between pulse pressure variation and stroke volume variation), effective arterial elastance, arterial compliance (Cart), and systemic vascular resistance were taken every 30 min in the endotoxin group until shock was induced. In the control group, these variables were measured every 30 min for 3 h. Subsequently, a fluid load was administered to both groups, and measurements were repeated every 30 min. After 1 hour of shock induction, the endotoxin group was divided into two subgroups: one receiving norepinephrine (END-NE) and the other not receiving it (END-F). Results: EaDyn showed an association with Cart, while pulse pressure variation was connected to both pulsatile and steady components, and stroke volume variation was solely associated with steady components. In addition, EaDyn exhibited higher values in the END groups than in the control group when shock was achieved. Furthermore, after the administration of norepinephrine, EaDyn displayed higher values in END-F than in END-NE. Conclusions: The EaDyn variable helps identify changes in the pulsatile component of arterial load, providing valuable guidance for management strategies aimed at improving cardiac performance.

The effect of migration on HIV high-risk behaviors among Mexican migrants.

BACKGROUND: Previous studies have shown an association between Mexican migration to the United States and an increased frequency of HIV high-risk behaviors among male Mexican migrants. However, the individual level change in these behaviors after migration has not been quantified. OBJECTIVE: To estimate the change in HIV high-risk behaviors among Mexican migrants after migration to the United States. METHODS: A case-crossover study was embedded in the California-Mexico Epidemiological Surveillance Pilot, a targeted, venue-based, sampling survey. We implemented the study from July to November 2005, studying 458 Mexican migrants at sites in rural and urban areas in Fresno County and San Diego County and directly comparing individual HIV high-risk behaviors before and after migration. RESULTS: After migration, there were increases in the odds of male migrants engaging in sex with a sex worker [odds ratio (OR) = 2.64, P < 0.0001], sex while under the influence of drugs or alcohol (OR = 5.00, P < 0.0001), performing sex work (OR = 6.00, P = 0.070), and sex with a male partner (OR = 13.00, P = 0.001). Those male Mexican migrant subgroups at particularly elevated risk were those in the United States for more than 5 years, those from the youngest age cohort (18-29 years old), or those frequenting high-risk behavior venues and male work venues. CONCLUSIONS: Our results show that Mexican migrant men were significantly more likely to engage in several HIV high-risk behaviors after migration to the United States. However, a smaller proportion of men reported low condom use after migration, indicating increased adoption of some prevention methods. Our results also identified subgroups of Mexican migrants at elevated risk who should be targeted for HIV prevention interventions.

Matching AIDS and tuberculosis registry data to identify AIDS/tuberculosis comorbidity cases in California.

The purpose of this study was to evaluate the sensitivity and positive predictive value (PPV) of a registry data linkage procedure used in the California AIDS and Tuberculosis (TB) Registry Data Linkage Study to identify AIDS/TB comorbidity cases in California. The California AIDS registry data from 1981 to 2006 were linked to the California TB registry data from 1996 to 2006 using LinkPlus, a probabilistic record linkage program developed by the Centers for Disease Control and Prevention, and matched results were manually reviewed to determine true or false matches. We estimated the sensitivity of this procedure to range from 98.0 per cent (95% confidence interval, CI: 97.3%, 98.7%) to 98.8 per cent (95% CI: 98.1%, 99.2%), and the PPV to be 100 per cent (95% CI: 96.8%, 100.0%). Our study demonstrated the feasibility of using this linkage procedure to match AIDS and TB registry data with a very high degree of accuracy.

Methamphetamine and cocaine use among Mexican migrants in California: the California-Mexico Epidemiological Surveillance Pilot.

Methamphetamine and cocaine use have been associated with a vulnerability to HIV infection among men who have sex with men and among men who have sex with women but not specifically among Mexican migrants in the United States. The California-Mexico Epidemiological Surveillance Pilot was a venue-based targeted survey of male and female Mexican migrants living in rural and urban areas in California. Among men (n = 985), the percentage of methamphetamine/cocaine use in the past year was 21% overall, 20% in male work venues, 19% in community venues, and 25% in high-risk behavior venues. Among women, 17% reported methamphetamine/cocaine use in high-risk behavior venues. Among men, methamphetamine/cocaine use was significantly associated with age less than 35 years, having multiple sex partners, depressive symptoms, alcohol use, sexually transmitted infections (including HIV), and higher acculturation. Prevention interventions in this population should be targeted to specific migrant sites and should address alcohol, methamphetamine, and cocaine use in the context of underlying psychosocial and environmental factors.

A comparison of perinatal HIV prevention opportunities for Hispanic and non-Hispanic women in California.

Using a semi-structured survey and convenience sample of pregnant/recently delivered Hispanic (n = 453) and non-Hispanic (n = 904) women in four California counties, this study compared rates of timely prenatal care (PNC) initiation, HIV test counseling, test offering, and test acceptance in PNC between Hispanic and non-Hispanic women. Hispanic women were less likely to report timely PNC initiation (69.3% vs. 80.4%, p < .0001), receiving test offer (69.5% vs. 76.7%, p = .002), and ever having been tested (77.3% vs. 87.9%, p < .0001) than non-Hispanic women. Hispanic women were more likely to report not knowing where to go (p = .04) and having no insurance (p < .001), transportation (p = .001), and child care (p = .007) as reasons for late PNC start. Both Hispanic and non-Hispanic women most commonly accepted a test offer for their health/health of their baby; Hispanic women were more likely to accept based on doctor/nurse recommendation (80.1% vs. 62.7%, p < .001). A quarter of Hispanic and non-Hispanic women reported they didn't feel they had a choice or that test was done automatically. Efforts to improve perinatal HIV prevention opportunities for all women in California are required. Furthermore, Hispanic women may have disparities in receipt of prenatal care and HIV test offer that need additional attention.

Knowledge of sexual partner's HIV serostatus and serosorting practices in a California population-based sample of men who have sex with men.

OBJECTIVES: To describe knowledge of primary and secondary sexual partner's HIV serostatus and sexual practices, including serosorting, among men who have sex with men (MSM) living in California. METHODS: Men who self-identified as gay/bisexual in the 2001 California Health Interview Survey, a statewide biennial random-digit-dial survey interviewing more than 50,000 adults on a variety of health topics, were recontacted in 2002 and interviewed by telephone about injection drug use, their own and partner's HIV serostatus, and sexual risk behaviors. RESULTS: Among 220 men who reported a primary partner, 86% [95% confidence interval (CI): 77-92] knew their primary partner's serostatus; 62% (95% CI, 52-70) of the 250 men who reported a secondary partner knew their most recent secondary partner's HIV serostatus. Knowledge of one's most recent secondary partner's HIV serostatus was inversely related to history of injecting recreational drugs (odds ratio, 0.22; P < 0.01), and reporting a primary partner in the past year (odds ratio, 0.37; P < 0.05). Two-fifths (41%) of HIV-positive men and three-fifths (62%) of HIV-negative men engaged in serosorting (serocordant unprotected anal intercourse) with their primary partners, whereas 33% HIV-positive men and 20% HIV-negative men did so with their most recent secondary partners. CONCLUSIONS: This population-based survey documented the extent to which MSM know their partners' serostatus and practice serosorting behaviors. The findings emphasize the need for studies to report serocordant and serodiscordant unprotected anal intercourse separately, as the former presents significant lower risk of HIV transmission.

The effect of venue sampling on estimates of HIV prevalence and sexual risk behaviors in men who have sex with men.

OBJECTIVE: The objective of this study was to investigate differences in HIV prevalence and sexual risk behaviors among men who have sex with men (MSM) according to their gay venue visit patterns. METHODS: In a cross-sectional survey, a population-based sample of men aged 18 to 64 years who self-identified as gay or bisexual were interviewed by telephone regarding their sexual behaviors, HIV serostatus, and gay venue visit patterns. RESULTS: A total of 398 men were recruited for the study. The results showed that frequent gay venue visitors were more likely to engage in high-risk sexual behaviors. Among gay venue attendees who visited different types of gay venues, men who visited sex clubs/bathhouses reported the highest rates of 5 or more male sexual partners and unprotected anal intercourse (UAI) with secondary partners (62.6% and 34.6%, respectively), gay bar/club attendees and cruisers reported higher rates of having sex with women (8.5% and 14.8%, respectively), and circuit party attendees reported the highest HIV prevalence (40.4%) and serodiscordant UAI (30.2%). CONCLUSIONS: MSM who visited different types of gay venues and with varied visit frequency showed marked differences in sexual risk behaviors, and the differences suggest the importance of weighting procedure to obtain unbiased estimates in venue-based studies.

HIV prevalence and sexual risk behaviors among men who have sex with men: results from a statewide population-based survey in California.

OBJECTIVES: To investigate HIV prevalence, sexual risk behaviors, and HIV testing among men who have sex with men (MSM) between 18 and 64 years old living in California. DESIGN: Cross-sectional study of a statewide population-based sample of MSM. METHODS: Using data from the 2001 California Health Interview Survey (CHIS 2001), 398 men who self-identified as gay or bisexual were recontacted and interviewed by telephone for a follow-up study in 2002. Study participants were interviewed regarding their demographic characteristics and sexual behavior, HIV testing history, and HIV infection status. Those who self-reported as HIV-negative or of unknown status were offered an HIV test using a home urine specimen collection kit. RESULTS: HIV prevalence among MSM in California was 19.1% (95% confidence interval [CI]: 12.8% to 25.3%) with higher rates seen among the following subgroups: high school or less education (40.4%), annual income less than dollar 20,000 (35.0%), or history of ever injecting recreational drugs (40.3%). Young age and Hispanic or African-American race/ethnicity were associated with higher proportions of risky sexual behavior and lower HIV testing rates. CONCLUSIONS: HIV prevalence among MSM living in California continues to be high across the whole state, and population-based studies are needed periodically to complement findings from surveys using other sampling designs.

Unique challenges to preventing perinatal HIV transmission among Hispanic women in California: results of a needs assessment.

To identify rates and factors associated with timely prenatal care (PNC) initiation, HIV test counseling, test offering, and test offer acceptance, we conducted a semistructured survey of a convenience sample of pregnant/recently delivered Hispanic women (n=453, 418 with analyzable data) in four California counties in 2000. Only 68.4% and 43.5% of Hispanic women reported receiving an HIV test offer and counseling, respectively, though 88.8% of those offered a test accepted. After controlling for the effects of age, education, years lived in the United States, health insurance coverage, delivery status, and parity, Hispanic women who initiated prenatal care in the first trimester were 1.7 times more likely to be offered an HIV test and almost 3 times more likely to receive counseling than women with a later prenatal care start or no prenatal care. Factors associated with timely PNC initiation on multivariate analysis were private/HMO insurance (OR=10.7, p < .001), Medi-Cal insurance (OR = 4.32, p < .001), being 25-30 years old (OR = 3.0, p = .008), and completion of high school (OR = 2.07, p = .01). Key opportunities to prevent perinatal HIV transmission are being lost for Hispanic women in California. Interventions to increase timely PNC initiation, and to improve test offering by health care providers, may help to improve counseling and testing rates for this population.

The epidemiology of HIV among Mexican migrants and recent immigrants in California and Mexico.

For Mexican migrants and recent immigrants, the impact of migration from Mexico to California has the potential to lead to an increased risk for HIV infection. Until recently, the prevalence of HIV in Mexico and among Mexican migrants in California appeared to be stable and relatively low. Recent studies have raised new concerns, however, that the HIV epidemic may expand more aggressively among this population in the coming years. Unfortunately, the insufficient amount of data available within recent years makes it difficult to fully assess the potential for rapid spread of the HIV epidemic among this population. Consequently, there is a critical need for an ongoing binational surveillance system to assess prevalence and trends in HIV/STD/TB disease and related risk behaviors among this population both in Calfornia and within this population's states of origin in Mexico. This enhanced epidemiologic surveillance system should provide improved data on the subpopulations at the highest risk for HIV/STD/TB, such as men who have sex with men, and should provide the opportunity to evaluate the impact of migration on the transmission dynamics, risk behaviors, and determinants of behavior on each side of the border. It is essential that this potential threat be assessed and that intervention programs are developed and implemented to combat this possible escalation in the HIV epidemic.

Self-reported sexual identity, sexual behaviors and health risks.

SUMMARY Data from a population-based survey of low-income young women (n = 2,438) was used to examine substance use patterns and exposure to coerced sexual activity among women who self-identify as lesbian (n = 34) or bisexual (n = 91), or who report sexual behavior exclusively with other women (n = 17) or with both women and men (n = 189). Findings for women classified by self-identity and by sexual behavior are compared. Women who identified as bisexual or lesbian reported higher rates of lifetime and recent substance use and were more likely to report experiences of coerced sex than women who identified as heterosexual. Women with both male and female sex partners reported higher rates of substance use and coerced sexual experiences than did women with male partners only. Heterosexual women with both male and female partners were more similar to self-identified bisexuals, compared to heterosexual women with male partners only. The implications of assessing multiple dimensions of sexual orientation in research focusing on lesbians' mental health are discussed.

Ethnic disparity in HIV prevalence and zidovudine treatment among childbearing women and pediatric AIDS cases in California.

OBJECTIVE: To compare, by ethnicity, the prevalence of HIV and zidovudine treatment among a cross-sectional survey of childbearing women in California in 1998, and the number of pediatric AIDS cases from 1998 to 2001. METHODS: Blood specimens, collected via infant heel-stick for metabolic screening during the third quarter of 1998, were anonymously tested for HIV antibody. Positive specimens were subsequently tested for evidence of zidovudine therapy. Pediatric AIDS cases with diagnosis dates from 1998 to 2001 were obtained from the AIDS case registry. RESULTS: Of the 119 108 specimens tested, 77 (0.65 per 1000) were HIV-antibody positive. Most (37.7%) of the 77 HIV-positive specimens were from newborns of African-American mothers, followed closely by Latina mothers (35.1%). The absence of zidovudine therapy was highest for Latina and African-American women, 29.6 and 24.1%, respectively. Latino and African-American children accounted for the majority of California pediatric AIDS cases diagnosed between 1998 and 2001. CONCLUSION: Innovative approaches are needed to increase the rate of zidovudine therapy among African-American and Latina HIV-infected childbearing women. These could include a shorter-course zidovudine regimen or rapid HIV testing and counselling of women in late-term pregnancy.

Prenatal HIV counseling and testing in California: women's experiences and providers' practices.

Two concurrent surveys were conducted in four California counties to compare the prenatal HIV counseling and voluntary testing (C&VT) experiences of women with the self-reported practices of prenatal care providers. Participants were 850 women currently or recently receiving prenatal care and 254 providers. Although 79.9% of women reported being offered an HIV test during a prenatal visit, only 56.2% said they were told about the risks and benefits of taking an HIV test. Almost all providers (98.4%) indicated they offer an HIV test, and 76.8% reported offering counseling, to every patient. One third of the women (65.9%) knew that treatment exists for reducing the chance of prenatal transmission of HIV, and 78.7% of women said they were more likely to be tested given knowledge of such therapy. Women may have underreported prenatal C&VT because providers spend insufficient time discussing related issues or because C&VT information is not presented in a way that is relevant to all patients.