Acceptability and Appropriateness of Digital PrEP Interventions for Black and Latina Cisgender Women: Perspectives From Service Providers in Los Angeles County

BACKGROUND

Black and Latina cisgender women (BLCW) experience disproportionately high rates of HIV infection compared with White women. BLCW also experience disparities in uptake of pre-exposure prophylaxis (PrEP), a highly effective HIV prevention strategy. Digital technology interventions may help to improve PrEP accessibility among BLCW and address barriers to receiving PrEP services in clinical settings.

METHODS

We conducted a formative implementation research project with service providers to explore the use of digital technology interventions to improve PrEP care continuum outcomes among priority populations in Los Angeles County. A thematic analysis approach was then used to assess the perceived acceptability and appropriateness of digital PrEP interventions for BLCW.

RESULTS

Of the five technology products presented, service providers viewed the stand-alone telemedicine platforms as the most acceptable intervention type for BLCW. Service providers also noted perceived benefits and barriers that BLCW may experience in using stand-alone telemedicine platforms, and offered recommendations for tailoring the products to meet the individual needs of BLCW.

CONCLUSIONS

Digital PrEP interventions may help address barriers BLCW experience in accessing PrEP in clinical settings. We offer suggestions of implementation strategies to optimize the use of digital PrEP interventions among BLCW.

Barriers and motivators to pre-exposure prophylaxis uptake among Black and Latina transgender women in Los Angeles: perspectives of current PrEP users

The purpose of this qualitative study was to identify barriers and motivators to PrEP uptake from the perspective of Black and Latina transgender women (TW) who are currently using PrEP to suggest intervention and outreach activities to increase PrEP uptake in this population. The Information-Motivation-Behavioral Skills Model guided the development of the semi-structured interview guide. A thematic analysis approach was used to analyze the data. Perceived barriers to PrEP uptake included structural and logistic barriers, language and cultural barriers to medical engagement, lack of transgender competent or gender-affirming care, and prioritizing hormone therapy over the use of PrEP. To increase PrEP uptake among BLTW, participants recommended disseminating PrEP information through a variety of methods, highlighting relationship and sexual health benefits of using PrEP, and developing effective patient-provider communication. Our findings highlight several ways to promote PrEP among BLTW. PrEP promotion should be integrated into gender-affirming care and supported by peer education and navigation services that reach BLTW in both clinic and community settings.

PrEP discontinuation among Latino/a and Black MSM and transgender women: A need for PrEP support services

Purpose

Disparities persist in HIV infection among Black and Latino men who have sex with men (BLMSM) and Black and Latina transgender women (BLTW). Increasing uptake and subsequent consistent use of pre-exposure prophylaxis (PrEP), an effective biomedical strategy for preventing HIV acquisition, can dramatically reduce HIV incidence in these populations. The purpose of this study was to explore reasons for PrEP discontinuation among BLMSM and BLTW living in Los Angeles County to inform the development of support services for these populations to remain persistent with their PrEP regimen.

Methods

In-depth, semi-structured interviews were conducted with 15 BLMSM and 7 BLTW who reported either temporary or indefinite PrEP discontinuation. A thematic analysis approach was used to analyze qualitative data.

Results

Four themes emerged related to reasons for PrEP discontinuation, including: (1) lower perceived HIV risk related to changes in sexual behavior; (2) structural or logistical barriers (e.g., lapse or loss of health insurance, cost, difficulty navigating complex medical systems); (3) anticipated and experienced medication side effects, with a sub-theme of interactions between PrEP and feminizing hormone medications; and (4) challenges with medication adherence.

Conclusions

PrEP is an important prevention tool for BLMSM and BLTW, particularly during periods of heightened HIV risk. However, both individual (e.g., inability to adhere to medication, changes in HIV sexual risk behaviors) and structural/logistical (e.g., loss of insurance, navigating complex medical systems) factors can cause temporary or indefinite PrEP discontinuation. Additional support services, beyond those offered by medical providers, are needed to help BLMSM and BLTW PrEP users overcome barriers to discontinuation and assist them to remain persistent with their PrEP regimen. We describe potential options for support services such as PrEP case management, expanded PrEP navigation services, or text messaging services.

Predictors of Internet Health Information-Seeking Behaviors Among Young Adults Living With HIV Across the United States: Longitudinal Observational Study

BACKGROUND

Consistent with young adults' penchant for digital communication, young adults living with HIV use digital communication media to seek out health information. Understanding the types of health information sought online and the characteristics of these information-seeking young adults is vital when designing digital health interventions for them.

OBJECTIVE

This study aims to describe characteristics of young adults living with HIV who seek health information through the internet. Results will be relevant to digital health interventions and patient education.

METHODS

Young adults with HIV (aged 18-34 years) self-reported internet use during an evaluation of digital HIV care interventions across 10 demonstration projects in the United States (N=716). Lasso (least absolute shrinkage and selection operator) models were used to select characteristics that predicted whether participants reported seeking general health and sexual and reproductive health (SRH) information on the internet during the past 6 months.

RESULTS

Almost a third (211/716, 29.5%) and a fifth (155/716, 21.6%) of participants reported searching for general health and SRH information, respectively; 26.7% (36/135) of transgender young adults with HIV searched for gender-affirming care topics. Areas under the curve (>0.70) indicated success in building models to predict internet health information seeking. Consistent with prior studies, higher education and income predicted health information seeking. Higher self-reported antiretroviral therapy adherence, substance use, and not reporting transgender gender identity also predicted health information seeking. Reporting a sexual orientation other than gay, lesbian, bisexual, or straight predicted SRH information seeking.

CONCLUSIONS

Young adults living with HIV commonly seek both general health and SRH information online, particularly those exploring their sexual identity. Providers should discuss the most commonly sought SRH topics and the use of digital technology and be open to discussing information found online to better assist young adults with HIV in finding accurate information. Characteristics associated with health information-seeking behavior may also be used to develop and tailor digital health interventions for these young adults.

Delivering PrEP to adults with "low" or "no" HIV risk and youth: experiences and perspectives of PrEP providers

Health care providers have an important role to play in expanding PrEP uptake to populations disproportionately burdened by HIV. In this study, in-depth, semi-structured qualitative interviews were conducted with 20 PrEP providers in Los Angeles, California to explore their experiences and perspectives prescribing PrEP. Overall, the findings indicate that providers generally adhered to US CDC clinical guidelines in determining PrEP eligibility. However, they also identified special considerations with respect to adults with "low" or "no" HIV risk. Three themes were developed from the data related to the delivery of PrEP to such individuals: 1) patients may not disclose sexual behaviours; 2) patient autonomy and agency; and 3) the importance of PrEP in gay male monogamous relationships. Two additional themes were identified related to prescribing PrEP to young people under the age of consent: 4) the need for more PrEP and sexual health education with youth and 5) challenges in providing PrEP to youth without parental consent. Findings highlight the importance of providing PrEP to patients who could potentially benefit from adoption, whether or not they present with clear behavioural indicators for PrEP. Providers should also consider the potential barriers to delivering PrEP to youth to ensure successful adoption among members of this population.

Qualitative Evaluation of Social Media and Mobile Technology Interventions Designed to Improve HIV Health Outcomes for Youth and Young Adults Living With HIV: A HRSA SPNS Initiative

Youth and young adults living with HIV (YYALH) are less likely to be engaged in HIV care, adhere to their medications, and achieve viral suppression compared to older adult populations. In the United States, the majority of YYALH belong to racial/ethnic, sexual, and gender minority groups. HIV care interventions are needed that specifically target YYALH and that exploit the use of social media and mobile technology (SMMT) platforms, where youth and young adults have a ubiquitous presence. We conducted a qualitative evaluation of SMMT interventions included in a Health Resources and Services Administration Special Projects of National Significance initiative designed to improve medical care engagement, retention, and medication adherence to achieve viral suppression among YYALH. However, in this study, only young adults living with HIV (YALH) ages 18 to 34 years participated. A total of 48 YALH were interviewed. The data were analyzed using thematic analysis and revealed three main themes supporting the usefulness of the SMMT interventions, which included (1) acceptability of SMMT interventions in managing HIV care with subthemes of medical information accessibility, reminders, and self-efficacy; (2) feelings of support and personal connection afforded by SMMT interventions; and (3) SMMT interventions help to alleviate negative feelings about status and mitigate HIV-related stigma. A few participants identified problems with using their respective intervention, primarily related to the functionality of the technologies. Overall, findings from our qualitative evaluation suggest that SMMT-based interventions have the potential to increase engagement and retention in care, support YALH in adhering to medication, and help them adjust to their diagnosis.

Barriers and motivators to pre-exposure prophylaxis uptake among Black and Latina transgender women in Los Angeles: perspectives of current PrEP users

The purpose of this qualitative study was to identify barriers and motivators to PrEP uptake from the perspective of Black and Latina transgender women (TW) who are currently using PrEP to suggest intervention and outreach activities to increase PrEP uptake in this population. The Information-Motivation-Behavioral Skills Model guided the development of the semi-structured interview guide. A thematic analysis approach was used to analyze the data. Perceived barriers to PrEP uptake included structural and logistic barriers, language and cultural barriers to medical engagement, lack of transgender competent or gender-affirming care, and prioritizing hormone therapy over the use of PrEP. To increase PrEP uptake among BLTW, participants recommended disseminating PrEP information through a variety of methods, highlighting relationship and sexual health benefits of using PrEP, and developing effective patient-provider communication. Our findings highlight several ways to promote PrEP among BLTW. PrEP promotion should be integrated into gender-affirming care and supported by peer education and navigation services that reach BLTW in both clinic and community settings.

Experiences of Pre-Exposure Prophylaxis Stigma, Social Support, and Information Dissemination Among Black and Latina Transgender Women Who Are Using Pre-Exposure Prophylaxis

Purpose: In the United States, HIV disproportionally affects Black and Latina transgender women (BLTW). Pre-exposure prophylaxis (PrEP) is a proven biomedical method for preventing HIV acquisition. However, the social stigma attached to using PrEP may deter uptake and persistence of PrEP among BLTW, two highly vulnerable populations. The purpose of this study was to explore the experiences of PrEP stigma among BLTW who are using PrEP in Los Angeles County. Methods: In-depth, semistructured interviews were conducted with BLTW PrEP users (N=19) to explore experiences of anticipated, enacted, and internalized PrEP stigma within the context of their unique social and contextual factors. A thematic analysis approach was used in the analysis of qualitative data. Results: We noted an underlying theme of HIV stigma related to participants' identification as trans women that served as the social context for other experiences. In addition, our data revealed five themes related to the experience of using PrEP. Three themes were specifically related to PrEP stigma and included: (1) Perception that BLTW PrEP users are HIV-positive; (2) perception that BLTW PrEP users engage in elevated sexual risk behaviors; and (3) negative labels ascribed to BLTW PrEP users. A fourth theme identified was the positive experiences of social support after PrEP disclosure reported by BLTW. Our fifth theme identified involved the dissemination of PrEP information by BLTW to friends/peers and sex partners. Conclusion: BLTW experience PrEP stigma within the context of PrEP disclosure. This experience is underscored by existing experiences of HIV stigma connected to their identity as trans women. PrEP providers should prepare BLTW to use selective disclosure practices when revealing their PrEP use to help minimize experiences of PrEP stigma or potential physical harm. PrEP implementation programs should also support peer-to-peer PrEP education programs for transgender women to promote positive views of PrEP and help facilitate PrEP uptake in this population.

Persistent stigmatizing and negative perceptions of pre-exposure prophylaxis (PrEP) users: implications for PrEP adoption among Latino men who have sex with men

The Centers for Disease Control and Prevention (CDC) estimates the lifetime HIV risk is one in four for Latino men who have sex with men (MSM). Pre-Exposure Prophylaxis (PrEP) is an efficacious biomedical prevention strategy to help prevent the acquisition of HIV. At present, there has been limited uptake of PrEP by Latino MSM. Unfortunately, the negative perceptions and social stigma surrounding PrEP and those who use it may deter uptake of this novel prevention strategy, particularly among high-risk Latino MSM. In this qualitative study, we explore the experiences of using PrEP among Latino MSM. Participants were recruited using gay-oriented social and sexual networking apps to complete an interviewer-administered, semi-structured qualitative interview. Thematic analysis was used to identify emerging themes relating to perceptions of PrEP users and PrEP as an HIV prevention strategy. Major themes included: feelings of protection and sexual freedom; negative and stigmatizing labels associated with PrEP use; assumptions about sexual behaviors and perceptions of sexual risk taking and irresponsibility; and attitudes related to PrEP use in relationships. A striking but not prevalent theme was the perception reported by participants that monolingual Spanish-speaking Latino MSM are skeptical about the effectiveness of PrEP. These findings suggest that efforts are needed to address the stigmatizing and negative perceptions of PrEP that persist in the gay community that may deter adoption among Latino MSM.

Predictive value of fetal hepatic biometry for birth weight and cord blood markers in gestational diabetes

OBJECTIVE

The objective of this study is to evaluate third-trimester fetal liver biometry, to predict birth weight and cord markers at birth in diabetic pregnancies.

STUDY DESIGN

Fetal liver biometry (liver diameters, area and volume) was obtained between 32 and 34 weeks. A blood sample was obtained from cord after birth. Receiver operating characteristic (ROC) curve models were evaluated for 75th and 90th birth weight percentile. Univariate and multivariate models were used.

RESULT

All the hepatic diameters, area and sectional volume demonstrated significant differences in both birth weight percentile ⩾75 and ⩾90. All ROC curves showed significant values. A significant association was observed for all measurements with birth weight. In multivariate model, liver area volume gave significant values for predicting birth weight. Cord leptin, c-peptide and ferritin were related to fetal hepatic size.

CONCLUSION

The hepatic changes in gestational diabetes were valid to predict birth weight and metabolic changes at birth.

Glutathione S-transferase, glutathione peroxidase and acetylcholinesterase activities in mussels transplanted to harbour areas

As part of an integrative monitoring campaign involving water and sediment chemistry, in situ bioassays, and mussel bioaccumulation and biomarkers, Mytilus galloprovincialis mussels of standard size were transplanted from a clean location to five sites in two important harbours from the Atlantic coast of Spain (Vigo and Pasaia). After a 30-day field exposure, the concentrations of major contaminants (trace metals, polychlorinated biphenyls and polycyclic aromatic hydrocarbons) accumulated in mussel tissues were measured at each site, and a mussel bioaccumulation index (MBI) was calculated. The enzymatic activity levels of glutathione S-transferase (GST), glutathione peroxidase (GPx) and acetylcholinesterase (AChE) were quantified in the gills of transplanted mussels (n=12). Mussels from the most polluted sites consistently exhibited significantly higher GST and GPx activities compared to the control site, whereas AChE activity was significantly inhibited. The responses of the GST and GPx activities were related to MBI, trace metals and PAH concentrations in mussels, whereas AChE activity was related to the trace metals concentrations in mussels. The above results suggest that GST and AChE activities can be used as potential biomarkers for active monitoring in marine coastal ecosystems. However, at this moment, GPx activity is not robust enough to be applicable to harbour areas.

Application of Toxicity Identification Evaluation (TIE) procedures for the characterization and management of dredged harbor sediments

This study refers to the performance of Phase I Toxicity Identification Evaluation (TIE) procedures to identify the contaminants (i.e. organic compounds, metals and ammonia) exerting toxicity in marine sediments from the Pasaia harbor (Oiartzun estuary, northern Spain). The effectiveness of the manipulations to reduce toxicity was proved with the marine amphipod survival test (whole-sediment) and the sea urchin embryo-larval assay (elutriates). By means of TIEs it was concluded that organic compounds were the major contaminants exerting toxicity, although toxic effects by metals was also demonstrated. Additionally, the combination of Phase I treatments allowed to investigate the toxicity changes associated to the mobility of contaminants during dredging activities. Therefore, the performance of TIE procedures as another line of evidence in the decision-making process is recommended. They show a great potential to be implemented at different steps of the characterization and management of dredged harbor sediments.

Integrative sediment assessment at Atlantic Spanish harbours by means of chemical and ecotoxicological tools

This study refers to the integrative assessment of sediment quality in three harbour areas at the Spanish Atlantic Coast: Vigo (Northwestern Spain), Bilbao and Pasajes (Northern Spain). At each site, two lines of evidence have been considered: chemical analyses (metal, PAH and PCB concentrations in sediments and ammonia concentration in bioassays) and toxicity tests (Microtox®, Corophium sp. marine amphipod and Paracentrotus lividus sea urchin larvae). Chemical and ecotoxicological results have been integrated by means of a tabular matrix and a multivariate factorial analysis (FA). Highly toxic samples have been characterised in Vigo and Pasajes harbours while Bilbao samples present toxicity levels ranging from non-toxic to moderately toxic. High toxicity is associated with high levels of contaminants whereas confounding factors (ammonia, organic matter and mud) have been identified to be the main cause of low to moderate toxicity. Based on the obtained results, it can be concluded that deriving potential toxicity of sediments based on comparison with Sediment Quality Guidelines (SQGs) is in agreement to toxicity results in areas presenting high levels of contaminants. However, at lower levels of toxicity (low to moderate), the mismatch between the potential toxicity (SQG approach) and the toxicity measured by bioassays is greater, as the former only accounts for chemical concentrations, without considering the interaction between contaminants and the effect of confounding factors. Contrarily, the multivariate analysis seems to be a robust tool for the integration and interpretation of different lines of evidence in areas affected by different sources of contamination.

Prenatal diagnosis of right aortic arch: associated findings, pregnancy outcome, and clinical significance of vascular rings

OBJECTIVES

To analyze the characteristics and clinical implications of right aortic arch (RAA) detected in fetal life.

METHODS

Retrospective study of all cases of RAA diagnosed prenatally in high-risk patients who underwent fetal echocardiography between 2000 and 2007.

RESULTS

There were 48 RAA; 18 had vascular ring (Group 1), including 15 RAA with aberrant left subclavian artery and 3 double aortic arch, and 30 had not vascular ring (Group 2), all RAA with mirror-image branching. The prenatal diagnosis was confirmed in 94%. In Group 1 most fetuses had normal heart (89%), and none had 22q11 deletion. There were 16 live births and all infants but one are asymptomatic (mean follow-up of 31 months). In Group 2 almost all fetuses had congenital heart defects (CHDs) (97%), and five were chromosomally abnormal (17%), including four 22q11 deleted. The 1-year survival rate was 69%, which was significantly higher in Group 1 (89% vs 57%, p < 0.05).

CONCLUSIONS

RAA can be accurately diagnosed by fetal echocardiography. The outlook for these patients largely depends on the presence of associated defects, mainly CHDs, and their severity. If isolated, aortic arch anomalies are asymptomatic vascular variants in most cases. This information is important to assist parental counseling in pregnancy.

Gestational diabetes mellitus in a cohort of HIV-1 infected women

OBJECTIVES

We undertook a prospective study to estimate the prevalence of gestational diabetes mellitus (GDM) and associated risk factors in a cohort of 669 HIV-1 infected women.

METHODS

The O'Sullivan and glucose tolerance tests were performed during regular visits of 609 mothers.

RESULTS

The median age of the cohort was 30.7 years (range 16-44), with most women having had heterosexual contact (67%). The majority were in Centers for Disease Control (CDC) category A (71%) and 53% exhibited hepatitis C co-infection. Median viral load and CD4 count at third trimester were 545 cells/microL (range 139-1690 cells/microL) and 1.9 log (range 1.7-5.4), respectively. Seventy-four per cent of the patients were treated with highly active antiretroviral therapy (HAART), of whom 41% received a protease inhibitor (PI). An above-average prevalence of 7% [95% confidence interval (CI) 5.2-9.5] for positive GDM diagnosis was found. Risk factors associated with GDM in univariate analysis included older age, hepatitis C co-infection, stavudine and PI exposure. However, only older age [adjusted odds ratio (AOR) 1.09, 95% CI 1-1.1] and PI exposure (AOR 2.4, 95% CI 1-5.3) remained as independent risk factors for GDM development in multivariate analysis.

CONCLUSIONS

In our cohort, the prevalence of GDM appears to be increased, with older age and PI exposure contributing as significant independent risk factors.

Conotruncal anomalies in fetal life: accuracy of diagnosis, associated defects and outcome

OBJECTIVES

To assess the accuracy of prenatal echocardiography, associated anomalies, and outcome of fetuses with conotruncal anomalies (CTA).

STUDY DESIGN

We searched our database for CTA prenatally diagnosed between 1990 and 2005. We included tetralogy of Fallot (TOF), transposition of the great arteries (TGA), double-outlet right ventricle (DORV), truncus arteriosus (TA), pulmonary atresia with ventricular septal defect (PA-VSD) and posterior malalignment type VSD with aortic arch obstruction (pmtVSD-AAO). Data of 144 fetuses with complete follow-up were retrieved and analyzed.

RESULTS

The main reason for referral was suspected heart defect on a routine obstetric scan (72%). Most cases were detected < or =22 weeks (55%). The presence of a CTA was confirmed postnatally in 143 cases (99%), and the diagnosis of the first fetal echocardiography was correct in 126 (87.5%). Most diagnosis of TOF (33/36, 91.7%), TGA (34/38, 89.5%) and DORV (34/38, 89.5%) were proved correct. Inadequate assessment of the interventricular septum, the distal aortic arch and/or the severity of the right outflow tract obstruction accounted for most errors. The accuracy rate was lower in TA (11/14, 78.6%) and PA-VSD (4/7, 57.1%), with evaluation of the branch pulmonary arteries as the main source of discrepancies. In 7/18 incorrect cases subsequent scans allowed to obtain a correct diagnosis. Most fetuses (64%) had an isolated CTA. Thirty-seven had chromosomal anomalies (26%) but none were found in TGA. 22q11 deletion affected 8.7% of the tested patients. Nuchal translucency (NT) was above 95th centile in 19/104 cases (18%) in which NT were measured. Fifty cases were interrupted. The overall one-year survival rate was 71%, with differences between cases with and without associated defects (9/25, 36% vs. 57/68, 83.8%; p<0.01). The uncomplicated forms of TGA and TOF had the best survival rates (100%).

CONCLUSIONS

Most CTA can be diagnosed by fetal echocardiography with a high degree of accuracy. Chromosomal defects should always be ruled out, except for simple TGA. Current survival figures in many isolated CTA, especially simple TGA and TOF, support a change in the "classical" concept that congenital heart defects detected prenatally often have the worst outlook.

CONDENSATION

Most CTA can be diagnosed by fetal echocardiography with a high degree of accuracy. Isolated CTA are more common and most of these may have a favourable outcome.

Role of uterine artery Doppler in interpreting low PAPP-A values in first-trimester screening for Down syndrome in pregnancies at high risk of impaired placentation

OBJECTIVES

Low maternal serum levels of pregnancy-associated plasma protein-A (PAPP-A) are associated with both increased risk of aneuploidies and impaired trophoblastic invasion, while high uterine artery (UtA) resistance is associated with impaired trophoblastic invasion but not with an increased risk of aneuploidies. The aim of this study was to determine whether high UtA resistance plays a role in explaining low PAPP-A levels in the absence of aneuploidies.

METHODS

This was a prospective study of 116 singleton pregnancies at high risk for impaired placentation (having at least one major risk factor: prior history of pre-eclampsia, pregestational diabetes mellitus, chronic hypertension, chronic kidney disease, body mass index >30, autoimmune disorder, thrombophilia or recurrent pregnancy loss), booked for routine assessment of risk for aneuploidies by means of the first-trimester combined screening test (nuchal translucency thickness (NT) + PAPP-A + beta-human chorionic gonadotropin (beta-hCG)). Measurement of NT and the mean UtA pulsatility index (PI) were carried out at the 11 to 13 + 6-week scan. All values were calculated in multiples of the median (MoM) adjusted for gestational age. A cut-off risk of 1/270 at time of sampling was adopted to differentiate high- from low-risk groups for trisomy 21.

RESULTS

There were 108 patients deemed to be at low risk for trisomy 21 and eight at high risk. None had chromosomal defects, giving a false-positive rate for trisomy 21 of 6.9%. The greatest differences between patients at low risk and those at high risk for trisomy 21 were found in their PAPP-A (0.98 vs. 0.38 MoM, P < 0.01) and beta-hCG (1.09 vs. 1.77 MoM, P = 0.04) values. Greater NT thickness (1.02 vs. 0.90 MoM) and higher mean UtA-PI (1.05 vs. 0.96 MoM) were recorded in the high-risk group, although the differences did not reach statistical significance (P = 0.19 and 0.40, respectively). After log-transformation there were no significant correlations between mean UtA-PI and NT and between mean UtA-PI and beta-hCG. There was a significant negative linear correlation between mean UtA-PI and PAPP-A (r = -0.331; P < 0.01). After adjusting the PAPP-A values by UtA-PI, the false-positive rate for trisomy 21 decreased to 2.6%.

CONCLUSION

Mean UtA-PI at the 11 to 13 + 6-week scan may be an effect-modifier variable for PAPP-A that should be taken into account in the first-trimester combined screening for aneuploidies, at least in pregnancies at high risk for impaired placentation.

Hypoplastic left heart syndrome diagnosed in fetal life: associated findings, pregnancy outcome and results of palliative surgery

OBJECTIVES

To analyze the main prenatal characteristics of hypoplastic left heart syndrome (HLHS), its association with extracardiac anomalies including increased nuchal translucency (NT) and the outcome of affected patients.

METHODS

We searched our database for classical forms of HLHS (aortic atresia, mitral and aortic atresia and critical aortic stenosis evolved to a severely hypoplastic left ventricle) prenatally diagnosed between 1998 and 2006. Data on 101 fetuses were retrieved and analyzed.

RESULTS

The main reason for referral was suspected heart defect on a routine ultrasound scan (82%). The mean gestational age at diagnosis was 21 weeks. Most cases were detected at < or = 22 weeks (72%), the upper limit for termination of pregnancy (TOP) in our country (Spain). An intact atrial septum was diagnosed in 11 of the 58 fetuses (19%) in which pulmonary vein blood flow was assessed, and this diagnosis was proved to be correct in the six liveborn babies. Most fetuses (68%) had an isolated HLHS. Fourteen fetuses (14%) were chromosomally abnormal and all had associated extracardiac defects. NT was above the 95th centile in 21 of the 74 cases (28%) in which this measurement was available. 79% (58/73) of the cases in which HLHS was detected at < or = 22 weeks were terminated, and no differences in the rate of TOP were found through the study period. Among the 43 continuing pregnancies, seven fetuses died in utero and there were 36 live births; in 12 cases the parents opted for compassionate care and 24 chose to have the infant surgically treated. In the cohort of intention-to-treat cases, the overall survival rate was 36% (9/25). This rate improved from 18% (2/11) in the period 1998-2002 to 50% (7/14) in 2003-2006. There were no survivors in cases with intact atrial septum or when there were associated defects. At follow-up, 2/9 survivors suffered from significant neurological morbidity.

CONCLUSIONS

Fetal echocardiography allows an accurate diagnosis of HLHS, which is made in most instances in the first half of pregnancy. Despite the advantage offered by the prenatal detection of HLHS, which provides the opportunity to plan perinatal management, our up-to-date results show that the outlook for these fetuses is still poor, and highlight the importance of presenting these figures when counseling parents with affected fetuses.

Effect of humic acids on speciation and toxicity of copper to Paracentrotus lividus larvae in seawater

The effects of humic acid (HA) on the toxicity of copper to sea urchin Paracentrotus lividus larvae were studied in chemically defined seawater. Square Wave Anodic Stripping Voltammetry (SWASV) was employed to study the complexation of copper in seawater medium. A simple complexation model assuming one ligand type and a 1:1 reaction stoichiometry successfully explained the inverse titration experiments. A conditional stability constant of 6.53+/-0.05 and a complexating capacity of 230+/-7 micromol Cu/g HA were obtained. Sea urchin bioassay tests with two endpoints, embryogenesis success and larval growth were carried out in order to study the toxicity of dissolved copper in both the presence and absence of HA. The toxicity data obtained fitted well into a logistic model, and the high sensitivity of both endpoints (EC(50) were 41.1 microg Cu/l and 32.9 microg Cu/l, respectively) encourages their use for biomonitoring. The HA had a clearly protective effect, reducing the toxicity of Cu to the sea urchin larvae. The labile copper, rather than the total copper concentrations, explained the toxicity of the Cu-HA solutions, and the Cu-HA complexes appeared as non-toxic forms. These results are in agreement with the Free Ion Activity Model, because the labile Cu concentrations in this buffered and chemically defined medium covary with the free ion activity of the Cu, validating the model to naturally occurring HA in the marine environment.

Synthesis and biological studies of glycosyl dopamine derivatives as potential antiparkinsonian agents

A new approach to deliver dopamine into the central nervous system, based on the use of D-glucose as transportable agent, has been studied. Glycosyl dopamine derivatives bearing the sugar moiety linked to either the amino group or the catechol ring of dopamine through amide, ester or glycosidic bonds were synthesised as potential antiparkinsonian agents. Studies on the binding to dopamine D2 receptor, in vitro stability, and locomotive effect in mice of the synthetic glycoconjugates are reported.

Determination of carbendazim in soil samples by anodic stripping voltammetry using a carbon fiber ultramicroelectrode

A method for the determination of carbendazim (MBC) by anodic stripping voltammetry using a carbon fiber ultramicroelectrode was developed. The ultramicroelectrode was made in our laboratory and its electrochemical behavior was characterized by measuring the electrochemical response with a solution of potassium ferricyanide. The optimum parameters used for the determination of MBC are the following: 0.05 M phosphate buffer at pH 2.0 as supporting electrolyte; a scan rate of v = 10.00 V s(-1) and an accumulation potential of Eac = 0.00 V. The MBC was determined in a soil sample with the method proposed and the results found were comparable to those obtained by HPLC.

In vivo effects of new inhibitors of catechol-O-methyl transferase

1. The effects of two new synthetic compounds showing in vitro catechol-O-methyl transferase (COMT) inhibitor properties were studied in vivo and compared with the effects of nitecapone and Ro-41-0960. 2. QO IA (3-(3-hydroxy-4-methoxy-5-nitrobenzylidene)-2,4-pentanedione), QO IIR ([2-(3,4-dihydroxy-2-nitrophenyl)vinyl]phenyl ketone), nitecapone and Ro-41-0960 (30 mg kg(-1), i.p.) were given to reserpinized rats 1 h before the administration of L-DOPA/carbidopa (LD/CD, 50:50 mg kg(-1), i.p.). Locomotor activity was assessed 1 h later. All the COMT inhibitors (COMTI), with the exception of QO IA, markedly potentiated LD/CD reversal of reserpine-induced akinesia. Similar results were obtained when the COMTI were coadministered with LD/CD. The effect of compound QO IIR was dose-dependent (7.5-30 mg kg(-1), i.p.). 3. The COMTI (30 mg kg(-1), i.p.) potentiated LD/CD reversal of both catalepsy and hypothermia of reserpinized mice. 4. QO IIR, nitecapone and Ro-41-0960 (30 mg kg(-1), i.p.) reduced striatal 3-methyl-DOPA (3-OMD) levels and increased dopamine (DA) and dihydroxyphenylacetic acid (DOPAC) levels. Compound QO IA was devoid of any effect on striatal amine levels. In contrast to the other inhibitors, Ro-41-0961 reduced HVA levels as well. The effect of QO IIR on striatal amine levels was dose-dependent (7.5-60 mg kg(-1), i.p.) 5. These results suggest that the new compound QO IIR is an effective peripherally acting COMT inhibitor in vivo.

Determination of thyroxine in urine by cathodic stripping square-wave voltammetry

A square-wave polarographic method for the determination of the amino acid thyroxine in urine, after isolation from the matrix on a C18 Sep-Pak cartridge and subsequent elution through a column packed with Amberlite IRA-400 anionic resin, was developed. The optimal working conditions for the application of the method were found to be pH 10, provided by a carbonate buffer, and a potential of -0.690 V during 10 min. The equilibration time was applied during 5 s, and potential scans were performed at a square-wave amplitude of 100 mV and a scan rate of 300 mV s-1, with a square-wave frequency of 100 Hz. The measuring-system response was linear over the thyroxine concentration range from 10 to 60 ng ml-1 and the detection limit achieved was 2.71 ng ml-1. The relative error and relative standard deviation obtained were 1.18 and 4.67%, respectively.

Kinetics of the reversible tight-binding inhibition of pig liver catechol-O-methyltransferase by [2-(3,4-dihydroxy-2- nitrophenyl)vinyl]phenyl ketone

The inactivation of partially purified pig liver catechol-O-methyltransferase (COMT) by [2-(3,4-dihydroxy-2-nitrophenyl)vinyl]phenylketone has been studied. The results demonstrated that COMT is inhibited in a reversible tight-binding fashion with an apparent Ki of 0.2 microM. IC50 values were determined at different concentrations of both substrates of the enzymatic reaction, pyrocatechol and S-adenosyl-L-methionine (AdoMet). The plot of IC50 versus pyrocatechol concentration gave a straight line, suggesting competitive inhibition. However the nitrocatechol derivative showed an uncompetitive inhibition pattern when measured as a function of AdoMet concentration.

Inhibition of catechol-O-methyltransferase by 1-vinyl derivatives of nitrocatechols and nitroguaiacols. Kinetics of the irreversible inhibition by 3-(3-hydroxy-4-methoxy-5-nitro benzylidene)-2,4-pentanedione

It is well known that activated alkene derivatives react with thiol groups according to a Michael's addition reaction. On the basis of the presence of at least one thiol group essential for the activity of catechol-O-methyltransferase (COMT), several 1-vinyl derivatives of nitrocatechol and nitroguaiacol were synthesized and tested as potential irreversible active site-directed inhibitors of COMT. All the synthesized products were potent inhibitors of partially purified pig liver COMT. However, the inhibition was reversible in most cases, with the exception of 3-(3-hydroxy-4-methoxy-5-nitrobenzylidene)-2,4-pentanedione (compound 2) which inhibited COMT in an irreversible manner. When the inhibition of COMT was measured as a function of the length of time of pre-incubation with 2, biphasic kinetics were observed, suggesting the modification of at least two thiol groups which are essential for COMT activity. The analysis of the two parts of the inhibition curve as a function of the inhibitor concentration showed that compound 2 modified the more reactive group in a non-specific manner, while it behaved as an active site-directed inhibitor on the second slow-reacting thiol group. Importantly, a saturating concentration of S-adenosyl-L-methionine (AdoMet) in the pre-incubation mixture gave pseudo-first order kinetics, suggesting total protection of one thiol group. Magnesium ions had no effect on the protection of COMT by AdoMet. In the presence of 3,5-dinitrocatechol (DNC) slight protection of COMT was observed; when the inactivation of both groups was analysed independently, protection of the specifically modified group was detected, while the reaction with the other group was faster in the presence of DNC. When both AdoMet and DNC were present, inactivation of COMT by 2 was not observed, suggesting that both reacting groups are located at or near the active site.

Dihydroxynitrobenzaldehydes and hydroxymethoxynitrobenzaldehydes: synthesis and biological activity as catechol-O-methyltransferase inhibitors

A series of nitro derivatives of dihydroxy- and hydroxymethoxybenzaldehyde was synthesized and tested as potential inhibitors of partially purified pig liver catechol-O-methyltransferase (COMT). All the dihydroxynitrobenzaldehydes prepared were potent inhibitors of COMT, but only one hydroxymethoxynitrobenzaldehyde (3-hydroxy-4-methoxy-5-nitrobenzaldehyde) showed activity as a COMT inhibitor. Although previously reported data showed that the presence of electron-withdrawing substituents at position 5 seemed to be very important for activity as COMT inhibitor, our results suggest that the requirement necessary to enhance the activity of the dihydroxyni-trobenzaldehyde derivatives toward COMT is the presence of the nitro group in a position ortho with respect to one hydroxyl group. The assayed compounds showed a reversible inhibition of COMT, which was mixed for all the dihydroxynitro derivatives but noncompetitive for 3-hydroxy-4-methoxy-5-nitrobenzaldehyde when pyrocatechol was the variable substrate and uncompetitive in all the inhibitors with respect to S-adenosyl-L-methionine.

Substrate specificity of small-intestinal lactase. Assessment of the role of the substrate hydroxyl groups

Lactase-phlorizin hydrolase is a disaccharidase present in the small intestine of mammals. This enzyme has two active sites, one being responsible for the hydrolysis of lactose. Lactase activity is thought to be selective towards glycosides with a hydrophilic aglycon. In this work, we report a systematic study on the importance of each hydroxyl group in the substrate molecule for lactase activity. For this purpose, all of the monodeoxy derivatives of methyl beta-lactoside and other lactose analogues are studied as lactase substrates. With respect to the galactose moiety, it is shown here that HO-3' and HO-2' are necessary for hydrolysis of the substrates by lactase. Using these chemically modified substrates, it has been confirmed that lactase does not behave as a typical beta-galactosidase, since it does not show an absolute selectivity with respect to substitution and stereochemistry at C4' in the galactose moiety of the substrate. However, the glucose moiety, in particular the HO-6, appears to be important for substrate hydrolysis, although none of the hydroxyl groups seemed to be essential. In order to differentiate both activities of the enzyme, a new assay for the phlorizin-hydrolase activity has also been developed.

Kinetic and inhibition studies on catechol-O-methyltransferase affinity labelling by N-(3,4-dihydroxyphenyl)maleimide

Initial velocity and product inhibition studies have been performed on soluble catechol-O-methyltransferase which has been partially purified from pig liver. The results are consistent with an ordered reaction mechanism, in which S-adenosyl-L-methionine (AdoMet) is the leading substrate. The enzyme is irreversibly inhibited by maleimide derivatives in a biphasic manner, which suggests a differential reaction with two thiol groups. N-(3,4-Dihydroxyphenyl)maleimide, which has a reactive moiety (maleimide ring) and an affinity moiety (catechol ring), acts as an affinity labelling compound on the more reactive SH group; AdoMet and Mg2+ protect against this modification. Total protection of this SH group results in a pseudo-first-order inhibition of the enzyme, with the apparent rate constant being proportional to the inhibitor concentration. All the other maleimide derivatives studied inhibited the enzyme by reacting with one of the two SH groups in a non-specific manner. The reaction of the other, more reactive, SH group was either specific (active-site-directed) or non-specific, depending on the substituent present in the affinity moiety and also on the length of an intermediate chain of methylene groups present between this moiety and the reactive maleimide ring. In the presence of both AdoMet and Mg2+, 3,5-dinitrocatechol, a reversible inhibitor of the enzyme which is competitive with respect to the catechol substrate, protects the enzyme from inactivation by any of the maleimide derivatives. The adducts of these maleimide derivatives formed with dithiothreitol inhibit the enzyme reversibly, showing inhibition patterns that are consistent with the mechanism deduced from the initial velocity and product inhibition studies.

Inhibition of catechol-O-methyltransferase by N-(3,4-dihydroxyphenyl) maleimide

Catechol-O-methyltransferase (COMT) is inhibited rapidly and irreversibly by N-(3,4-dihydroxyphenyl) maleimide. S-adenosylmethionine (AdoMet) and magnesium ions protect the enzyme from inactivation by this compound, but no protection is observed by the catechol substrate. However, the corresponding succinimide analogue shows a reversible inhibition of COMT, which is competitive with pyrocatecholphthalein and non-competitive with AdoMet. Amino-group reagents also inhibit COMT and this inhibition is protected by AdoMet, suggesting that sulphydryl and amino groups essential for activity are located in an AdoMet-binding site on COMT. The maleimide derivative may be considered to be an active-site directed inhibitor.