Vessel Sampling and Blood Flow Velocity Distribution With Vessel Diameter for Characterizing the Human Bulbar Conjunctival Microvasculature.

PURPOSE: This study determined (1) how many vessels (i.e., the vessel sampling) are needed to reliably characterize the bulbar conjunctival microvasculature and (2) if characteristic information can be obtained from the distribution histogram of the blood flow velocity and vessel diameter. METHODS: Functional slitlamp biomicroscope was used to image hundreds of venules per subject. The bulbar conjunctiva in five healthy human subjects was imaged on six different locations in the temporal bulbar conjunctiva. The histograms of the diameter and velocity were plotted to examine whether the distribution was normal. Standard errors were calculated from the standard deviation and vessel sample size. The ratio of the standard error of the mean over the population mean was used to determine the sample size cutoff. The velocity was plotted as a function of the vessel diameter to display the distribution of the diameter and velocity. RESULTS: The results showed that the sampling size was approximately 15 vessels, which generated a standard error equivalent to 15% of the population mean from the total vessel population. The distributions of the diameter and velocity were not only unimodal, but also somewhat positively skewed and not normal. The blood flow velocity was related to the vessel diameter (r=0.23, P<0.05). CONCLUSIONS: This was the first study to determine the sampling size of the vessels and the distribution histogram of the blood flow velocity and vessel diameter, which may lead to a better understanding of the human microvascular system of the bulbar conjunctiva.

Slitlamp Photography and Videography With High Magnifications.

PURPOSE: To demonstrate the use of the slitlamp photography and videography with extremely high magnifications for visualizing structures of the anterior segment of the eye. METHODS: A Canon 60D digital camera with Movie Crop Function was adapted into a Nikon FS-2 slitlamp to capture still images and video clips of the structures of the anterior segment of the eye. Images obtained using the slitlamp were tested for spatial resolution. The cornea of human eyes was imaged with the slitlamp, and the structures were compared with the pictures captured using the ultra-high-resolution optical coherence tomography (UHR-OCT). The central thickness of the corneal epithelium and total cornea was obtained using the slitlamp, and the results were compared with the thickness obtained using UHR-OCT. RESULTS: High-quality ocular images and higher spatial resolutions were obtained using the slitlamp with extremely high magnifications and Movie Crop Function, rather than the traditional slitlamp. The structures and characteristics of the cornea, such as the normal epithelium, abnormal epithelium of corneal intraepithelial neoplasia, laser in situ keratomileusis interface, and contact lenses, were clearly visualized using this device. These features were confirmed by comparing the obtained images with those acquired using UHR-OCT. Moreover, the tear film debris on the ocular surface and the corneal nerve in the anterior corneal stroma were also visualized. The thicknesses of the corneal epithelium and total cornea were similar to that measured using UHR-OCT (P<0.05). CONCLUSIONS: We demonstrated that the slitlamp photography and videography with extremely high magnifications allow better visualization of the anterior segment structures of the eye, especially of the epithelium, when compared with the traditional slitlamp.

Demographic and High-Risk Behaviors associated with HPV and HPV Vaccine Awareness among Persons Aged 15-74 Years in Puerto Rico.

OBJECTIVE: Studies of human papillomavirus (HPV) awareness in Puerto Rico (PR) are limited and are of interest given low HPV vaccine uptake in this population. This cross-sectional study aimed to determine factors associated to HPV and HPV vaccine awareness among persons aged 15-74 years living in Puerto Rico. METHODS: We analysed data from a sub-sample of 1,476 men and women who participated in a 2008 population-based island-wide household survey and who completed an HPV module. Multivariate logistic regression models were used to examine factors associated with HPV and HPV vaccine awareness. RESULTS: Overall, 37.2% of participants had heard about HPV and 33.4% had heard of the vaccine. Multivariate logistic regression showed that women were more likely to have heard of HPV (OR adjusted: 4.54; 95% CI=3.45, 5.98) or of the HPV vaccine (OR adjusted: 6.15; 95% CI=4.50, 8.40) as compared to men. HPV awareness was also lower among older adults, persons with lower income and with lower educational attainment, those without children and smokers (p < 0.05). CONCLUSION: In 2008, two years after the introduction of the first HPV vaccine in PR and the US, public awareness about HPV infection and the HPV vaccine was lower in Hispanics in PR as compared to other populations. Identified high-risk populations should be targeted in preventive care strategies. Future efforts should increase HPV knowledge and vaccine use in this population in order to maximize the impact of vaccination programs.

Binge drinking as a risk factor for violence among secondary school students in a nationally representative sample in Puerto Rico.

OBJECTIVE: The objective of this study was to determine the association between binge drinking and violence in a representative sample of secondary-school students in Puerto Rico. METHODS: Consulta Juvenil VII (a biennial survey of school-aged youths in Puerto Rico) has a representative sample of adolescent students in Puerto Rico. A multi-stage stratified cluster sampling design was used. The sampling frame of Consulta Juvenil VII includes all the public and private schools registered with the Department of Education and the Council of General Education in Puerto Rico. The study utilizes a self-administered questionnaire that was translated and adapted from the "Student Survey of Risk and Protective Factors and Prevalence of Alcohol, Tobacco, and Other Drug Use". "Binge drinking" was defined as having 5 or more alcoholic drinks in a row during the 30 days preceding the survey. RESULTS: Almost 20% of the sample members reported that at least 1 instance of binge drinking had taken place during the 2 weeks prior to the survey (17.7%). After controlling for gender, age, school level, the type of system, and the parents' educational levels, the odds of a given binge drinker reporting violent behaviors were 5 times greater than the odds among non-binge drinkers (OR: 5.6; 95% CI: 4.7-6.7). CONCLUSION: The study shows an association between binge drinking and violence in Puerto Rican adolescents, indicating that Hispanic youths who abuse alcohol may be at increased risk of violence. These findings suggest that violence prevention programs should be integrated with substance use prevention programs. [PR Health

PM2.5 Extracts Induce INFγ-Independent Activation of CIITA, MHCII, and Increases Inflammation in Human Bronchial Epithelium.

The capacity of particulate matter (PM) to enhance and stimulate the expression of pro-inflammatory mediators has been previously demonstrated in non-antigen-presenting cells (human bronchial epithelia). Nonetheless, many proposed mechanisms for this are extrapolated from known canonical molecular pathways. This work evaluates a possible mechanism for inflammatory exacerbation after exposure to PM2.5 (from Puerto Rico) and CuSO4, using human bronchial epithelial cells (BEAS-2B) as a model. The induction of CIITA, MHCII genes, and various pro-inflammatory mediators was investigated. Among these, the phosphorylation of STAT1 Y701 was significantly induced after 4 h of PM2.5 exposure, concurrent with a slight increase in CIITA and HLA-DRα mRNA levels. INFγ mRNA levels remained low amidst exposure time, while IL-6 levels significantly increased at earlier times. IL-8 remained low, as expected from attenuation by IL-6 in the known INFγ-independent inflammation pathway. The effects of CuSO4 showed an increase in HLA-DRα expression after 8 h, an increase in STAT1 at 1 h, and RF1 at 8 h We hypothesize and show evidence that an inflammatory response due to PM2.5 extract exposure in human bronchial epithelia can be induced early via an alternate non-canonical pathway in the absence of INFγ.

Quality Improvement in Thyroid Fine-Needle Aspiration Biopsy accuracy at San Juan City Hospital Endocrinology Clinics.

OBJECTIVE: This study aimed to determine if there was a reduction in the amount of non-diagnostic cytopathology results of thyroid fine-needle aspiration (FNA) biopsies performed at San Juan City Hospital (SJCH) endocrinology clinics since the inclusion of a cytopathologist at the clinics. METHODS: This research consisted of a retrospective analysis of thyroid nodule FNA biopsy results performed at SJCH endocrinology clinics. The biopsies analyzed were performed during academic years from July 2017-June 2018 and July 2018-June 2019, a period that reflects one academic year prior and a year after the inclusion of a cytopathologist to the clinics. The patients were classified into "pre group" and "post -group." Descriptive analysis was conducted, taking into consideration variables including sex, age, period, location, size of the nodule, and cytology results. A Chi-square test and Confidence Interval were used to assess the association and estimates between predictors and outcomes. RESULTS: From the 145 thyroid nodules biopsied, a total of 121 nodules (83.4%) resulted in diagnostic cytologic results, while 24 nodules (16.6%) were non-diagnostic. From the "pre group," 57 nodules (78.1%) had a diagnosis, while the other 16 (21.9%) were reported as non-diagnostic. From the "post group", 64 nodules (88.9%) had a diagnosis, while the other 8 (11.1%) resulted in non-diagnostic findings (p-value: = 0.08). Even though results were statistically non-significant, a clear trend towards a decrease in non-diagnostic samples was evident. CONCLUSION: In our study, there was a decrease in the number of non-diagnostic thyroid nodule FNA results after on-site adequacy determination guided by a cytopathologist.

Differential gender effects of depression on use of HIV medications among HIV-positive Puerto Rican drug users.

Many barriers to the use of HIV medications have been identified. Research findings have also shown a gender disparity in HIV care behaviors. However, interaction effects of gender with the potential barriers to use of HIV medications among HIV-positive minority drug users remain under-studied. This study examined interaction effects of gender with potential moderating factors (i.e., individual and network characteristics) on the use of HIV medications. Analyses were based on 260 HIV-positive Puerto Rican heroin and cocaine users, recruited in New York (N=178) and Puerto Rico (N=82) in 1998-2003. HIV status was assessed using OraSure, and heroin or cocaine use was verified by urinalysis. All participants were tested and interviewed at baseline and six-month follow-up (183 males; 77 females). In predicting use of HIV medications at follow-up (HIVMEDF), use of HIV medications at baseline (HIVMED), individual characteristics (e.g., depression), network characteristics (e.g., having an intravenous drug user [IDU] sex partner), recruitment site, and interaction effects of these variables with gender, were examined in multiple logistic regression analysis. Use of HIV medications was low (29% at baseline; 40% at follow-up). HIVMED, recruitment site, gender, and depression had significant main effects on HIVMEDF. Depression also had a significant interaction effect with gender on HIVMEDF. Unlike men, women with depression were less likely than women without depression to use the medications. The findings indicate that gender-specific issues should be addressed by treatment programs for HIV-positive drug users, with particular efforts needed to enhance use of medications for depressed women.

Knowledge of viral hepatitis among Puerto Rican adults: implications for prevention.

Although primary prevention of HAV and HBV can be achieved through vaccination, the burden of HCV can only be reduced through behavioral interventions to reduce its risk factors. This study evaluated knowledge regarding transmission, clinical manifestations and prevention of viral hepatitis in Puerto Rico. We assessed the level of knowledge about HAV (six questions), HBV (12 questions) and HCV (eight questions) among non-institutionalized Puerto Rican adults aged 21-64 years. Demographic characteristics and self-reported knowledge of these infections were determined through a face-to-face interview. A mean knowledge score was computed by summing correct responses to each scale. Mean knowledge scores according to demographics were compared using ANOVA or the Kruskal-Wallis test. Mean knowledge scores for HAV, HBV and HCV infections were 2.6 ± 1.5, 6.1 ± 2.4, and 3.6 ± 1.1, respectively. For HAV and HBV infections, the mean knowledge score significantly (P < 0.05) increased with age, level of counseling received and number of sources of information. However, for HCV infection the mean knowledge score significantly increased with decreasing age, increased educational level and increased annual family income. Contrary to HBV, a higher HAV and HCV knowledge score was observed among individuals with history of vaccination for HAV and HBV, seropositive status for HAV and HCV, and history of drug use. A sizeable proportion of adults in this study demonstrated an inadequate level of knowledge, especially about transmission routes. Health education must be focused on transmission and prevention methods, including the availability of a vaccine for HAV and HBV, especially among those with chronic liver disease.

Distribution of toxic metals and relative toxicity of airborne PM2.5 in Puerto Rico.

The exposure to airborne particulate matter (PM) and its constituents is an important factor to be considered when evaluating their potential health risk. Transition metals found in PM are known to contribute significantly to the exacerbation of respiratory ailments. Exposure to these constituents results in the induction of oxidative stress in the bronchial epithelium, thus promoting the secretion of inflammatory mediators. Therefore, it is important to know the contributions of PM2.5 constituents to further investigate their relationship with toxic responses and associated health risks. PM2.5 samples from three rural (Humacao, Guayama, and Guayanilla) and two urban (more populated) sites (Bayamón and Ponce) from Puerto Rico were analyzed for various inorganic constituents. A total of 59 trace elements were analyzed, of which eight were considered with the greatest toxic potential. The highest annual average concentration of PM2.5 was reported at the urban site of Ponce (5.82 ± 1.40 µg m-3), while Bayamón's average concentration was not as high (4.69 ± 1.30 µg m-3) compared to concentrations at the rural sites Humacao, Guayama, and Guayanilla (4.33 ± 1.20 µg m-3, 4.93 ± 1.50 µg m-3, and 4.88 ± 1.20 µg m-3 respectively. The concentration at the Ponce site exhibited the highest summer value (7.57 µg m-3) compared to that of all the rural sites (~ 6.40 µg m-3). The lowest summer PM2.5 values were obtained at the Humacao site with an average of 5.76 µg m-3. Average Cu and Zn concentrations were 3- and 2-fold higher at the urban sites (0.68 ng m-3 and 6.74 ng m-3 respectively) compared to the rural sites (0.17 ng m-3 and 4.11 ng m-3). Relative toxicity of inorganic PM extract indicates Bayamón (urban) and Guayama with similar low LC50 followed by Humacao, Guayanilla, and finally Ponce (urban) with the highest LC50. Of the eight potential toxic metals considered, only Fe was found to be higher at the rural sites. To our understanding, there are different sources of emission for these metals which potentially indicate main anthropogenic sources, together with the trade winds adding periodically volcanic and African Dust Storm particulates that affect Puerto Rico. These results are the first of their kind to be reported in Puerto Rico.

Seroepidemiology of viral hepatitis, HIV and herpes simplex type 2 in the household population aged 21-64 years in Puerto Rico.

BACKGROUND: Viral hepatitis and sexually transmitted infections (STIs) are key public health problems that pose an enormous risk for disease transmission in the general population. This study estimated, for the first time, prevalence estimates of serologic markers of HCV, HBV, HAV, HIV and HSV-2 in the adult population of Puerto Rico and assessed variations across sociodemographic and behavioral characteristics. METHODS: A seroepidemiologic survey was employed using a stratified cluster probability sample of households in Puerto Rico. Participants completed a face-to-face interview, a self-administered questionnaire using an ACASI system, and provided blood specimens for antibody testing. Prevalence estimates of viral hepatitis, HIV and HSV-2 were estimated using a logistic regression model weighting for the probability of participation in each household block and the inverse of the probability of selection according to geographic strata, households' blocks, and sex distribution. RESULTS: A total of 1,654 adults participated in the study. Seroprevalence estimates for HCV (2.3%, 95% CI: 1.3%-4.2%), HBV (3.1%, 95% CI: 2.0%-4.7%), and HSV-2 (22.3%, 95% CI: 18.5%-26.7%) in Puerto Rico are roughly in agreement with estimates obtained in the US population; however, HAV (41.3%, 95% CI: 36.9%-45.8%) and HIV (1.1%, 95% CI: 0.5%-2.3%) seroprevalence estimates in Puerto Rico were higher. The proportion of individuals that were unaware of their serostatus was as follows: 80% for HCV, 98.3% for HBV, 96.4% for HAV, 36.4% for HIV, and 97.8% for HSV-2. Post-stratification estimates of seroprevalence varied significantly by demographic and risk related characteristics. CONCLUSION: This data underscore the disproportionate impact of some viral infections across selected population subgroups in Puerto Rico. A concerted island-wide effort is needed to strengthen viral hepatitis and STIs prevention and control strategies, support surveillance to monitor chronic infections, and ensure appropriate counseling, testing, and medical management of infected persons. Integration of HCV, HBV, and HSV-2 counseling into HIV existing prevention services and outreach through social networks might represent a valuable approach to reach high-risk individuals.

The effectiveness evaluation of a multimedia hepatitis C prevention program for Hispanic HIV-infected individuals.

INTRODUCTION: With the introduction of highly active antiretroviral therapy, the hepatitis C virus (HCV) infection has become a primary health problem among individuals suffering from HIV/ AIDS in Puerto Rico, principally those who are injecting drug users (IDUs). A multimedia educational intervention, based on the Health Beliefs Model and Social Cognitive Theory was developed and implemented to reduce HCV-associated risk behaviors among IDUs. METHODS: A pre- and post- intervention study evaluated the knowledge and behavioral changes in a group of HIV-infected persons recruited from February 2006 through December 2008. RESULTS: A total of 110 participants were recruited: all were IDUs; 82% were men; 86.3% were HIV/HCV co-infected and 24.5% had active injected drugs in the month prior to recruitment. The group mean age was 42.2 +/- 9.2 years and mean educational level was 10th grade. Knowledge of HCV risk behaviors, perception of HCV susceptibility, and perception of disease severity increased after the intervention. Knowledge of HCV clinical manifestations and HIV co-infection complications and treatment also improved. In addition, HCV risk behaviors and injecting drug practice decreased significantly among IDUs. CONCLUSIONS: This new multimedia intervention captured and maintained the participants' attention and interest, facilitating their educational process. Thus, greater attention and interest leads to greater knowledge and prevention improvement.

Feasibility of collecting biologic specimens in population-based surveys: experiences from the epidemiology of hepatitis C in the household, adult population of Puerto Rico study.

The Behavioral Risk Factor Surveillance System (BRFSS) collects data on preventive health practices and risk behaviors that are linked to chronic diseases, injuries, and preventable infectious diseases that affect the adult population in all states and territories in the US. The BRFSS is currently the only survey conducted annually in Puerto Rico in the population aged 18 years and older; however, prevalence estimates are based on self-reports and therefore are subject to reporting errors. Although surveillance data are useful for the purpose of evaluation, program planning and health policy, surveys that collect biological specimens and clinical data provide a more accurate assessment of prevalence and a comprehensive picture of disease distribution and their risk factors. This article summarizes the methodology employed in a population-based study to estimate the seroprevalence of hepatitis C and other viral infections in Puerto Rico and shows the feasibility of combining different modes of data collection in population-based surveys that collect biologic specimens.

Lingual thyroid gland: it's time for awareness.

SUMMARY: Lingual thyroid (LT) gland is the most common type of ectopic thyroid tissue, but it is an extremely rare presentation. We present a case of a 41-year-old Hispanic female patient complaining of dysphonia and dysphagia. As part of the evaluation, fiber optic flexible indirect laryngoscopy (FIL) was performed which revealed a mass at the base of the tongue. The morphological examination was highly suspicious for ectopic thyroid tissue and the diagnosis was confirmed with neck ultrasound and thyroid scintigraphy. Although the patient presented subclinical hypothyroidism, levothyroxine therapy was initiated with a favorable response which included resolution of symptoms and mass size reduction. Our case portrays how thyroid hormone replacement therapy (THRT) may lead to a reduction in the size of the ectopic tissue and improvement of symptoms, thus avoiding the need for surgical intervention which could result in profound hypothyroidism severely affecting the patients' quality of life. LEARNING POINTS: Benign LT and malignant LT are indistinguishable clinically and radiographically for which histopathology is recommended. THRT, radioactive iodine 131 (RAI) therapy, and surgical excision are potential management options for LT. THRT may lead to size reduction of the ectopic tissue and resolution of symptoms avoiding surgical intervention.

Exploring Serum Transferrin Regulation of Nonferric Metal Therapeutic Function and Toxicity.

Serum transferrin (sTf) plays a pivotal role in regulating iron biodistribution and homeostasis within the body. The molecular details of sTf Fe(III) binding blood transport, and cellular delivery through transferrin receptor-mediated endocytosis are generally well-understood. Emerging interest exists in exploring sTf complexation of nonferric metals as it facilitates the therapeutic potential and toxicity of several of them. This review explores recent X-ray structural and physiologically relevant metal speciation studies to understand how sTf partakes in the bioactivity of key non-redox active hard Lewis acidic metals. It challenges preconceived notions of sTf structure function correlations that were based exclusively on the Fe(III) model by revealing distinct coordination modalities that nonferric metal ions can adopt and different modes of binding to metal-free and Fe(III)-bound sTf that can directly influence how they enter into cells and, ultimately, how they may impact human health. This knowledge informs on biomedical strategies to engineer sTf as a delivery vehicle for metal-based diagnostic and therapeutic agents in the cancer field. It is the intention of this work to open new avenues for characterizing the functionality and medical utility of nonferric-bound sTf and to expand the significance of this protein in the context of bioinorganic chemistry.

Pilot trial of an intervention aimed at modifying drug preparation practices among injection drug users in Puerto Rico.

Injection drug users (IDUs) contaminate preparation materials with blood-borne pathogens by using syringes as measuring and dispensing devices. In collaboration with IDUs, we developed a preventive intervention consisting of four new preparation practices aimed at avoiding the use of syringes in the preparation, and reducing the contamination of the materials. This report describes the results of a pilot trial introducing the new practices to ascertain their adoption potential and their potential efficacy in reducing contamination. Participants comprised 37 active IDUs among whom the new practices were promoted during 16 weeks. In addition to self-reported behaviors, the study collected cookers and plastic caps from shooting galleries and tested them for the presence of blood residues. Adoption rates were: (1) cleaning of skin area with hand sanitizer--65.6%; (2) directly pouring water with a dropper into the cooker--56.3%; (3) drawing drug solution with a preparation syringe and syringe filter--34.4%; and, (4) backload rinsing syringes--53.1%. Rates of blood residues detected in cookers and plastic caps were 41.7% prior to the trial, 28.6% at week 8, 24.6% at week 14, and 12.0% at week 18. We believe the results of the pilot trial are compelling and suggest that this intervention merits further formal testing.

Gender comparisons of factors associated with drug treatment utilization among Puerto Rican drug users.

OBJECTIVE: This study examined gender-specific effects of social bonds, network characteristics, and other factors on drug treatment enrollment among Puerto Rican drug users. METHOD: Participants (425 women; 1,374 men) were recruited in New York and Puerto Rico in 1998-2003. RESULTS: Gender differences were found: education (< high school/GED) and having a sex partner who is an injection drug user (IDU) were significantly related to current enrollment in drug treatment (EDT) for women; for men, having an IDU friend (negatively) had a main effect on EDT, and having an IDU friend also had a significant interaction effect with their own injection drug use on EDT. For both women and men, recruitment site (New York), having health insurance, and prior methadone treatment were significant predictors of EDT. CONCLUSION: The findings may be useful in developing gender-differentiated drug counseling and treatment efforts that engage women's sex partners and men's friendship networks to build support for drug treatment.

Rethinking the Dental Amalgam Dilemma: An Integrated Toxicological Approach.

Mercury (Hg) has been identified as one of the most toxic nonradioactive materials known to man. Although mercury is a naturally occurring element, anthropogenic mercury is now a major worldwide concern and is an international priority toxic pollutant. It also comprises one of the primary constituents of dental amalgam fillings. Even though dental mercury amalgams have been used for almost two centuries, its safety has never been tested or proven in the United States by any regulatory agency. There has been an ongoing debate regarding the safety of its use since 1845, and many studies conclude that its use exposes patients to troublesome toxicity. In this review, we present in an objective way the danger of dental amalgam to human health based on current knowledge. This dilemma is addressed in terms of an integrated toxicological approach by focusing on four mayor issues to show how these interrelate to create the whole picture: (1) the irrefutable constant release of mercury vapor from dental amalgams which is responsible for individual chronic exposure, (2) the evidence of organic mercury formation from dental amalgam in the oral cavity, (3) the effect of mercury exposure on gene regulation in human cells which supports the intrinsic genetic susceptibility to toxicant and, finally, (4) the availability of recent epidemiological data supporting the link of dental amalgams to diseases such as Alzheimer's and Parkinson.

Toxic Metals Depuration Profiles from a Population Adjacent to a Military Target Range (Vieques) and Main Island Puerto Rico.

Background: The island of Vieques (a municipality of Puerto Rico) was used as a military practice range by the US Navy for more than 60 years. Many studies have reported the presence of toxic metals in soil samples taken from Vieques. The bombing range is only 18 km upwind from the Vieques residential area and inhalable resuspended particles resulting from bombing are known to reach the populated area. The current study reports for the first time, the presence of toxic metals' depuration profiles obtained from Vieques and Main Island Puerto Rico human subjects. Objectives: This study was designed to evaluate the distribution of toxic metals in a random population exposed to contaminants originating from military activities and comparing it to a non-exposed random population from Main Island Puerto Rico. Methods: A total of 83 subjects studied; 32 were from Vieques and 51 were from Main Island Puerto Rico. A physician administrated chelation therapy to all subjects and collected urine samples during a 24-h period. A total of 20 trace elements associated with military activities were measured in urine by induced coupled plasma mass spectrometry (ICP-MS). The results were compared between both population samples. Results: Significant differences in the levels of eight trace elements associated with military practices were found between Vieques and Main Island Puerto Rico. Lead (Pb), aluminum (Al), uranium (U) (p < 0.001), arsenic (As), cadmium (Cd) (p = 0.02), and gadolinium (Gd) (p = 0.03) were significantly higher in Vieques while niobium (Nb) and platinum (Pt) levels (p < 0.006) were lower in the Vieques samples. Discussion: Higher concentrations of Pb, Al, As, Cd, Gd, and U were found in Vieques residents' urine samples compared to Main Island. Nonetheless, Pt and Ga were present in Main Island at higher concentrations than in Vieques. Although limited by its sample size, this report should set a basis for the importance of health assessment in these subjects exposed to military activities remnants throughout the years and further evaluation of their effects on the overall health of the population.

Stabilization of alpha-chymotrypsin upon PEGylation correlates with reduced structural dynamics.

Protein stability remains one of the main factors limiting the realization of the full potential of protein therapeutics. Poly(ethylene glycol) (PEG) conjugation to proteins has evolved into an important tool to overcome instability issues associated with proteins. The observed increase in thermodynamic stability of several proteins upon PEGylation has been hypothesized to arise from reduced protein structural dynamics, although experimental evidence for this hypothesis is currently missing. To test this hypothesis, the model protein alpha-chymotrypsin (alpha-CT) was covalently modified with PEGs with molecular weights (M(W)) of 700, 2,000 and 5,000 and the degree of modification was systematically varied. The procedure did not cause significant tertiary structure changes. Thermodynamic unfolding experiments revealed that PEGylation increased the thermal transition temperature (T(m)) of alpha-CT by up to 6 degrees C and the free energy of unfolding [DeltaG(U) (25 degrees C)] by up to 5 kcal/mol. The increase in stability was found to be independent of the PEG M(W) and it leveled off after an average of four PEG molecules were bound to alpha-CT. Fourier-transformed infrared (FTIR) H/D exchange experiments were conducted to characterize the conformational dynamics of the PEG-conjugates. It was found that the magnitude of thermodynamic stabilization correlates with a reduction in protein structural dynamics and was independent of the PEG M(W). Thus, the initial hypothesis proved positive. Similar to the thermodynamic stabilization of proteins by covalent modification with glycans, PEG thermodynamically stabilizes alpha-CT by reducing protein structural dynamics. These results provide guidance for the future development of stable protein formulations.

GC-MS confirmation of xylazine (Rompun), a veterinary sedative, in exchanged needles.

In order to assess the extent of xylazine (Xyz) injection in Puerto Rico, two waves of used-syringe collections were performed. In the first, syringes were gathered, anonymously and without additional information; in the second, a short interview, also anonymous, was administered. We found Xyz in 37.6% of the collected syringes; the majority of the Xyz-containing syringes came from ranching communities. Syringes containing Xyz more frequently also contained "speedball" than those without (90.6% and 66.7%, respectively). Self-reports of Xyz injection deviated markedly from actual detection: only 50% (self-described users) and 22% (self-described non-users) of the collected syringes contained the drug. With a high prevalence of skin ulcers (38.5% vs. 6.8%; p<0.001), Xyz users were more likely to be in poor health compared to non-users. Surprisingly, though a higher percentage of Xyz users than non-users had college-level educations (23.1% vs. 5.5%), they were more likely to be homeless (64.1% vs. 37%).