National Alcohol Survey of households in Trinidad and Tobago (NASHTT): Alcohol use in households.

BACKGROUND: To determine the patterns of alcohol use among households in Trinidad and Tobago (T&T) and to estimate the association between alcohol use and negative psychological, social, or physical events experienced by the household. METHODS: A convenience sample of 1837 households across T&T. We identified bivariate correlates of alcohol use, and heavy episodic drinking using chi-square and t-test analyses and used multivariable logistic regression to estimate adjusted associations between household alcohol use and experiences within the past 12 months adjusted for sociodemographic covariates. RESULTS: One thousand five hundred two households had complete data for all variables (82% response rate). Nearly two thirds (64%) of households included alcohol users; 57% of household that consumed alcohol also reported heavy episodic drinking. Households that reported alcohol consumption were significantly more likely to report illnesses within the households, relationship problems, and behavioral and antisocial problems with children. Among households where a member was employed, those who consumed alcohol were nearly twice as likely (OR = 1.98; 95% confidence interval (CI) 1.03, 3.82) to have a household member call in sick to work and 2.9 times as likely (OR = 2.9; CI 1.19, 7.04) to have a household member suffer work related problems compared with households who reported not consuming alcohol. CONCLUSIONS: Approximately two thirds of households in T&T reported using alcohol. These households were more likely to report psychological, physical, and social problems. These findings would support efforts to enforce current policies, laws, and regulations as well as new strategies to reduce the impact of harmful alcohol consumption on households in T&T.

Viewpoint: Why do we need a point-of-care CD4 test for low-income countries?

In this paper, we discuss the reasons why we urgently need a point-of-care (POC) CD4 test, elaborate the problems we have experienced with the current technology which hampers CD4-count coverage and highlight the ideal characteristics of a universal CD4 POC test. It is high-time that CD4 technology is simplified and adapted for wider use in low-income countries to change the current paradigm of restricted access once and for all.

The control of T cell responses by dendritic cell subsets.

Dendritic cells are known as the most efficient antigen-presenting cell type to activate naïve T cells; however, they are able to do more than just efficiently present antigen to T cells. They are key modulators of the immune response that can influence Th cell differentiation by preferentially inducing Th type 1 or 2 cell responses, and the differential polarisation of CD4(+) T cells appears to be mediated by discrete dendritic cell subsets.

Depression and its associated factors among patients attending chronic disease clinics in southwest Trinidad.

This study determined the prevalence of depression and associated factors, among patients attending chronic disease clinics in Southwest Trinidad. This was a cross-sectional survey using a sample of consecutive patients at four large clinics. To determine the presence of depression, an interviewer-applied modified Zung Scale was validated The modified Zung scale, at the cut-off index of 60, has a sensitivity of 60% and a specificity of 94%. Seven hundred and thirty-four completed questionnaires were received, a response rate of 76%. The patients were primarily Indo-Trinidadian (70%), over 50 years (76.4%) and female (72.3%). The prevalence of depression was 28.3%. There were statistically significant differences in the level of depression by age, gender, educational level achieved and occupation (p < 0.05). There were also statistically significant differences in the level of depression by the number of presenting complaints, the number of chronic diseases, the presence of arthritis, the presence of diabetes mellitus with another chronic disease and the presence of ischaemic heart disease (p < 0.05). No significant differences were found with respect to ethnicity (p = 0.97) or the presence of diabetes mellitus by itself (p = 0.34). Results of logistic regression indicate that the independent predictors of depression (p < 0.05) were the level of education achieved, those with higher levels of education had less depression; the number of presenting complaints, those with more presenting complaints were more likely to be depressed and the presence of arthritis and female gender. It is imperative that policy be developed to address the mental health problems of patients attending these chronic disease clinics.

Development of an enzyme immunoassay for rat soluble interleukin-2 receptors.

This study describes the development of a sandwich enzyme immunoassay (ELISA) for rat soluble IL-2 receptors (sIL-2R) using a combination of monoclonal antibodies reactive with different epitopes on the rat IL-2R. Coating plates with NDS61 and NDS64 monoclonal antibodies produced similar dose-response curves when incubated with a standard sIL-2R preparation followed by biotinylated OX39, streptavidin-alkaline phosphatase and the substrate. Although normal rat serum inhibited the assay, the effects were more profound when NDS64 was used as the capture antibody and subsequent development of the assay was performed using NDS61. The intra- and interassay variations were typically less than 5%. This assay will be valuable for monitoring immune activation status in a variety of experimental models.

CD44 expression in rejecting rat small bowel allografts.

CD44 is a widely expressed cell surface protein that recognizes multiple ligands and is involved in extra- and intercellular adhesion. The precise role of CD44 in immune interactions is currently unknown, but it is believed to be a homing receptor involved in lymphocyte trafficking and inflammatory responses. This study investigated CD44 expression in intestinal tissue after heterotopic rat small bowel transplantation and assessed the effect of transplantation on intestinal epithelial cell proliferation using an antibody to the nuclear activation Ag Ki67. Lamina propria and intestinal epithelial cell expression of CD44 was graded blindly by five observers, and villus epithelial cells were noted as being positive or negative for Ki67 staining. CD44 expression was high in the lamina propria of both allografted and isografted animals; however, there was no significant difference between the two groups. In contrast, the expression of CD44 on the villus epithelium was greater in allografted animals and progressed toward the villus tips as rejection developed, declining thereafter because of loss of villus integrity. Ki67 positivity was also greater in allografted animals but did not progress toward the villus tip. This is the first reported observation of CD44 expression on intestinal epithelium that is not restricted to the crypts. The findings indicate the involvement of CD44 in the rejection process and demonstrate changes in the proliferative profile of rejecting small intestinal epithelium. Further studies into adhesion molecules, such as CD44, may help to improve understanding of graft failure and promote the development of new therapeutic approaches for controlling and preventing graft rejection.

Differential expression of adhesion molecules during rat small bowel allograft rejection.

The adhesion molecules intercellular adhesion molecule 1 (ICAM-1), lymphocyte function-associated antigen-1 (LFA-1) (alpha and beta chains), and very late activation antigen-4 (VLA-4) have an essential role in cell-cell interactions and the initiation of immune responses. This study used an indirect immunoperoxidase technique to investigate the expression of these molecules in the lamina propria of allografts and isografts after heterotopic rat small bowel transplantation. Normal untransplanted small bowel served as additional controls. Overall, ICAM-1 and LFA-1 alpha expression was significantly higher in allografts, although there was variable expression of these molecules in isografted animals. There were temporal differences in the expression of ICAM-1 and LFA-1 alpha in that increased ICAM-1 expression was more pronounced in the the early posttransplant period, whereas there was a progressive increase in LFA-1 alpha as rejection developed. In contrast, there was no difference between allograft and isograft expression of LFA-1 beta and VLA-4. This study has demonstrated a preferential increase in adhesion molecule expression with developing rat small bowel allograft rejection and suggests that adhesion molecules are involved in the development and progression of allograft rejection. Although the observed differences in antigen expression are not as marked as those previously reported in other organ transplants, appropriate adhesion molecules may present suitable targets for immunotherapeutic protocols after small bowel transplantation.

Pseudodementia in a twenty-one-year-old with bipolar disorder and vitamin B12 and folate deficiency.

A twenty-one-year-old female known to suffer from bipolar type I disorder developed features of a pseudodementia. Following prompt initial response to treatment with antidepressants, there was an early recurrence of cognitive impairment. Blood investigations confirmed a macrocytic anaemia and vitamin B12 and folate deficiencies. There was dramatic resolution of cognitive impairment after vitamin replacement. This suggested the occurrence of a reversible nutritional dementia and reinforced the need to rule out secondary organic causes of psychiatric symptoms even in patients previously diagnosed with a primary psychiatric disorder.

HIV seroprevalence and risk factors in female substance abusers seeking rehabilitation in Trinidad and Tobago.

Crack cocaine use, especially among females, is associated with risky sexual behaviour. Data from 122 female substance abusers admitted to a rehabilitation centre in Trinidad and Tobago between 1996 and 2002 were retrospectively reviewed to determine Human Immunodeficiency Virus (HIV) seroprevalence and other associated risk factors. HIV seroprevalence was 19.7%, eight times higher than in the general population. Factors significantly associated with HIV infection were use of crack cocaine, low educational attainment and diagnosis of a sexually transmitted infection. Other factors associated with risky sexual behaviour were common--use of cocaine in combination with alcohol (65.6%), psychiatric illness (28.7%) and a history of sexual abuse (83%). Female substance abusers, especially female crack addicts are at high risk of acquiring and transmitting HIV. Rehabilitation programmes should include HIV prevention interventions which specifically target all risk factors including trauma counselling, skills development and screening for sexually transmitted infections.

Drug use, sexual behaviour and HIV risk of the homeless in Port-of-Spain, Trinidad.

Data were collected from 88 homeless persons in Port-of-Spain, Trinidad to assess HIV risk. 68% of the sample were engaging in unprotected sex with multiple partners, 25% were exchanging sex for money, and 29.5% were regularly smoking crack cocaine. Many had two or more of these behaviours that put them at high risk of HIV infection. Females were significantly more likely to be sex traders, to engage in bisexual behaviour and to have a history of psychiatric illness. The relationship between psychiatric illness and HIV risk behaviours among homeless female persons is explored. Educational interventions are suggested to reduce the public health risks in this population.

Substance abuse among first admissions to the psychiatric unit of a general hospital in Trinidad.

Admissions for first episode of psychiatric illness provide information on service utilization which can be used to improve service delivery. The present study reviews the use of in-patient general psychiatric services in southern Trinidad using data from first admissions in one year, specifically to determine service utilization by substance-abusing patients. Case files of all admissions to the psychiatric unit of the San Fernando General Hospital in one year were reviewed and analyzed for demographic data, substance abuse, diagnosis and associated features of the admission. Significant rates of substance abuse were found among first admissions. Of 123 new patients, 43.1% were diagnosed with a substance abuse disorder, 56.6% of whom had a comorbid psychiatric disorder. Patients with substance abuse problems tended to be young males. The substance most commonly abused was alcohol (26.8%) and alcohol abusers were more likely to be of East Indian descent. Management within this mental health catchment area needs to address identification, early intervention and prevention of substance abuse among psychiatric patients. It is proposed that both hospital and community-based substance abuse interventions should be employed in the management of acute psychiatric patients.

Cytokine regulation of CD44 expression on rat intestinal epithelial cells.

CD44 comprises a family of type I transmembrane glycoproteins that is expressed on a wide range of cells including those of epithelial, lymphoid and myeloid lineage. Although expression of CD44 in the small intestine is typically localised in the crypts of Lieberkuhn, we have reported the expression of CD44 on mature, intestinal villus epithelial cells during the development of small bowel allograft rejection. The mechanisms underlying CD44 up-regulation are unknown, although it may be influenced by localised cytokine production. This study used flow cytometry to assess the effects of recombinant IFN-gamma and TNF-alpha on CD44 expression and hyaluronan binding by the rat small intestinal epithelial cell lines, RIE and IEC 6. IFN-gamma upregulated CD44 expression on RIE (155% of unstimulated control) and IEC 6 (209% of unstimulated control) cells, whereas TNF-alpha had no effect. IFN-gamma had no qualitative effect on CD44, as binding of the ubiquitously expressed extracellular matrix polysaccharide hyaluronan was unchanged. RIE and IEC 6 cells expressed the 82 kDa and 130 kDa major isoforms of CD44, however cytokine stimulation did not affect the expression of these, nor did stimulation induce the expression of other variants. In summary, these findings demonstrate that CD44 expression by intestinal epithelial cells can be regulated by cytokines, yet their ability to bind hyaluronan and the isoform of the expressed CD44 remains unaltered. It appears that localised inflammatory conditions and cytokine production may modify epithelial cell expression of CD44, however the physiological role for such a response has yet to be elucidated.

Relationship between blood O2 content and catecholamine levels during hypoxia in rainbow trout and American eel.

Plasma catecholamine levels and arterial blood respiratory variables were monitored in rainbow trout (Oncorhynchus mykiss) and American eel (Anguilla rostrata) acutely exposed (30 min) to graded levels of external hypoxia [water PO2 (PWO2) 20-90 Torr]. The experiments were designed to evaluate the factors controlling catecholamine mobilization in hypoxic fish and to elucidate the basis of marked interspecific differences. In trout, plasma catecholamine levels were unchanged when PWO2 remained above 50 Torr but increased markedly when PWO2 was lowered below this value; the predominant catecholamine released into the circulation was epinephrine. In eel, there was no such obvious PWO2 threshold for catecholamine release although plasma levels were consistently elevated above baseline only at PWO2 less than 35 Torr. The magnitude of the catecholamine release in eel was approximately an order of magnitude less than in trout. Unlike in trout, there was no increase in the plasma epinephrine-to-norepinephrine concentration ratio. During hypoxia, the relationship between arterial blood PO2 (PaO2) and PWO2 was similar in both species and thus could not explain the differences in the PWO2 thresholds for catecholamine release. In trout, the calculated PaO2 thresholds for catecholamine release were 25.3 (epinephrine) and 20.5 Torr (norepinephrine) whereas in eel the corresponding values were 12.5 and 11.6 Torr, respectively. These PaO2 thresholds were in good agreement with the in vivo values for PaO2 at half-maximal hemoglobin (Hb)-O2 saturation (P50) for trout and eel blood of 22.9 and 11.1 Torr, respectively. Thus both species displayed essentially equivalent catecholamine release thresholds when expressed in terms of arterial blood O2 content corresponding to approximately 45-60% Hb-O2 saturation.

Quantification of presumptive Na(+)/H (+) antiporters of the erythrocytes of trout and eel.

The presumptive Na(+)/H(+) exchange sites of trout and eel erythrocytes were quantified using amiloride-displaceable 5-(N-methyl-N-[(3)H]isobutyl)-amiloride ((3)H-MIA) equilibrium binding to further evaluate the mechanisms of i) hypoxia-mediated modifications in the trout erythrocyte ß-adrenergic signal transduction system and ii) the marked differences in the catecholamine responsiveness of this system between the trout and eel. MIA was a more potent inhibitor of both trout apparent erythrocyte proton extrusion (IC50 = 20.1 ± 1.1 µmol l(-1), N = 6) activity (as evaluated by measuring plasma pH changes after addition of catecholamine in vitro) and specific (3)H-MIA binding (IC50 = 257 ± 8.2 nmol l(-1), N = 3) than amiloride, which possessed a proton extrusion IC50 of 26.1 ± 1.6 µmol l(-1) (N = 6) and a binding IC50 of 891 ± 113 nmol l(-1) (N = 3). The specific Na(+) channel blocker phenamil was without effect on adrenergic proton extrusion activity or specific (3)H-MIA binding. Trout erythrocytes suspended in Na(+)-free saline and maintained under normoxic conditions possessed 37,675 ± 6,678 (N = 6) amiloride-displaceable (3)H-MIA binding sites per cell (Bmax, presumptive Na(+)/H(+) antiporters) with an apparent dissociation constant (KD) of 244 ± 29 nmol l(-1) (N = 6). Acute hypoxia (PO2 = 1.2 kPa; 30 min) did not affect the KD, yet resulted in a 65% increase in the number of presumptive Na(+)/H(+) antiporters. Normoxic eel erythrocytes, similarly suspended in Na(+)-free saline, possessed only 17,133 ± 3,716 presumptive Na(+)/H(+) antiporters (N = 6), 45% of that of trout erythrocytes, with a similar KD (246 ± 41 nmol l(-1), N = 6). These findings suggest that inter- and intra-specific differences in the responsiveness of the teleost erythrocyte ß-adrenergic signal transduction system can be explained, in part, by differences in the numbers of Na(+)/H(+) exchange sites.

The relationship between beta-adrenoceptors and adrenergic responsiveness in trout (Oncorhynchus mykiss) and eel (Anguilla rostrata) erythrocytes.

Experiments were performed in vitro specifically to elucidate the underlying mechanism(s) of the attenuated adrenergic responses of eel (Anguilla rostrata) erythrocytes. This was achieved by comparing beta-adrenoceptor numbers and affinities in addition to (i) Na+/H+ exchange activity, (ii) cell swelling and (iii) cyclic AMP formation mediated by catecholamines in eel and trout (Oncorhynchus mykiss) erythrocytes under normoxic and hypoxic conditions. Under normoxic conditions, eel erythrocytes displayed a total absence of Na+/H+ exchange activity (as determined from measurements of extracellular pH) after addition of noradrenaline (50-1000 nmol l-1) in contrast to a pronounced dose-dependent response in trout. Incubation of the blood under hypoxic conditions, to achieve approximately 50% haemoglobin O2-saturation, further increased the extent of Na+/H+ exchange activation in trout and elicited a statistically significant, although physiologically small (10% of the response in trout), activation of H+ extrusion activity in eel. Catecholamine-mediated cell swelling, although obvious in trout, was absent in eel when estimated under hypoxic conditions. Eel erythrocytes possessed approximately 50% fewer surface beta-adrenoceptors than did trout erythrocytes, although the dissociation constants (KD) of these receptors did not differ between eel and trout. The numbers and affinities of the erythrocyte beta-adrenoceptors were not significantly affected by the hypoxic incubation. Both eel and trout erythrocytes displayed a dose-dependent elevation of cyclic AMP concentration in response to noradrenaline that was further increased by hypoxia. Surprisingly, eel erythrocytes produced larger quantities of cyclic AMP despite the lower numbers of surface beta-adrenoceptors. Thus, the absence of adrenergic swelling and the attenuated H+ extrusion response in eel erythrocytes cannot be attributed to insufficient numbers of beta-adrenoceptors or to functional uncoupling of these receptors from adenylate cyclase. Instead, the differences between trout and eel may reflect differing numbers of Na+/H+ exchangers or fundamental differences in the manner by which these exchangers are activated by cyclic AMP.

ß-adrenergic signal transduction in fish: interactive effects of catecholamines and cortisol.

The elevation of plasma catecholamine levels during acute stress initiates a series of compensatory physiological and biochemical mechanisms to alleviate the disruptive effects of stress on blood oxygen transport. Of particular importance is the ß-adrenergic activation of a Na(+)/H(+) antiporter associated with the red blood cell (rbc) membrane. Upon activation, the Na(+)/H(+) antiporter extrudes H(+) from the rbc and the resultant alkalinization of the rbc interior serves to enhance both the affinity and the capacity of haemoglobin O2 binding. The activation of the Na(+)/H(+) exchanger is dependent upon the intracellular accumulation of cyclic AMP. The extent of cyclic AMP accumulation is determined, in part, by the number and/or affinities of cell surface ß-adrenoreceptors. Recent studies have shown that the number of cell surface ß-adrenoreceptors are rapidly increased during acute hypoxia and that this phenomenon may explain the enhanced responsiveness of hypoxic rbc's to exogenous catecholamines.In certain instances, plasma catecholamine and cortisol levels rise concurrently. We recently have shown that chronic (10 day) elevation of cortisol levels, in vivo, or short-term (24h) elevation, in vitro, caused significant elevation of internalized ß-adrenoreceptors. Upon exposure of the rbc's to hypoxia, these additional receptors are rapidly recruited to the cell surface where they become functionally coupled to adenylate cyclase. Ultimately, therefore, chronic elevation of plasma cortisol levels increases the responsiveness of the rbc to circulating catecholamines. We recently have identified similar enhancement of cell surface ß-adrenoreceptors by cortisol and increased physiological responsiveness (glycogenolysis) to catecholamines in trout hepatocytes.Thus, chronic elevation of cortisol levels appears to be generally adaptive for increasing the sensitivity of the ß-adrenergic signal transduction system of at least two cell types (rbc's, hepatocytes) involved in the amelioration of acute stress when plasma catecholamine levels rise.