Can clinical features predict the likelihood of finding abnormalities when using capsule endoscopy in patients with GI bleeding of obscure origin?

BACKGROUND: Capsule endoscopy is becoming the investigation of choice for GI bleeding of obscure etiology. This study examined whether clinical or other features predict an increased likelihood of finding a lesion in patients with this type of bleeding. METHODS: Clinical and other data were collected prospectively for 92 patients undergoing capsule endoscopy for GI bleeding of obscure origin. Patients were divided into two groups: those with overt bleeding (42 patients) and those with anemia alone (50 patients). The relationship between these data and the findings at capsule endoscopy was examined. RESULTS: A definite or probable cause of bleeding was found in 60 patients (angiodysplasias 47, tumor 7, ulcer 3, gastric antral vascular ectasia 2). There was no difference between the two groups with respect to age, gender, mode of presentation, duration of bleeding, or need for transfusion. Lesions were found as often in patients who had only one preceding endoscopy and colonoscopy as in those who had multiple procedures. Colonic cleansing and cecal imaging by the capsule did not influence the result. Hospitalized patients were more likely to have an actively bleeding lesion detected. CONCLUSIONS: Capsule endoscopy is equally useful in patients with overt and occult GI bleeding of obscure origin. Capsule endoscopy should be performed early in the evaluation of these patients.     

Identification of a fibrin-independent platelet contractile mechanism regulating primary hemostasis and thrombus growth

A fundamental property of platelets is their ability to transmit cytoskeletal contractile forces to extracellular matrices. While the importance of the platelet contractile mechanism in regulating fibrin clot retraction is well established, its role in regulating the primary hemostatic response, independent of blood coagulation, remains ill defined. Real-time analysis of platelet adhesion and aggregation on a collagen substrate revealed a prominent contractile phase during thrombus development, associated with a 30% to 40% reduction in thrombus volume. Thrombus contraction developed independent of thrombin and fibrin and resulted in the tight packing of aggregated platelets. Inhibition of the platelet contractile mechanism, with the myosin IIA inhibitor blebbistatin or through Rho kinase antagonism, markedly inhibited thrombus contraction, preventing the tight packing of aggregated platelets and undermining thrombus stability in vitro. Using a new intravital hemostatic model, we demonstrate that the platelet contractile mechanism is critical for maintaining the integrity of the primary hemostatic plug, independent of thrombin and fibrin generation. These studies demonstrate an important role for the platelet contractile mechanism in regulating primary hemostasis and thrombus growth. Furthermore, they provide new insight into the underlying bleeding diathesis associated with platelet contractility defects.     

Increased dosage requirements of tobramycin and gentamicin for treating Pseudomonas pneumonia in patients with cystic fibrosis

The pharmacokinetic behavior of tobramycin and gentamicin was evaluated in 27 patients who had cystic fibrosis (CF). A previously studied, age-matched group of 334 patients who had been treated with gentamicin and who did not have CF served as controls. The CF patients, who ranged in age from 2 to 32 years and who had normal renal function, received 36 treatment courses with either tobramycin (19) or gentamicin (17) to treat Pseudomonas pneumonia. Serum concentrations were determined after a 1.5-mg/kg dose to compute half-life (t 1/2), elimination rate constant (k), and apparent volume of distribution (V). From these values, doses were calculated to produce steady-state peak concentrations of 8.0 micrograms/ml with a dosing interval of every six hours. For tobramycin the mean (+/- SD) t1/2 was 1.0 (0.4) hours, V was 0.18 (0.06) l/kg, total body clearance (TBC) was 2.19 (0.71) ml/min/kg, and the calculated dose was 8.2 (2.1) mg/kg/day. For gentamicin t1/2 was 1.1 (0.5) hours, V was 0.20 (0.06) l/kg, TBC was 2.28 (0.89) ml/min/kg, and the calculated dose was 8.8 (2.4) mg/kg/day. The pharmacokinetic parameters were not statistically different between the two drugs, but the mean values of t1/2 and TBC of CF patients differed significantly from those of the control group. The calculated doses were larger than the manufacturer's maximum recommended dose of 7.5 mg/kg/day for 63% of tobramycin and 71% of gentamicin treatment courses. A dosing interval change to every four hours would have been appropriate in 28 of the 36 treatment courses (78%).(ABSTRACT TRUNCATED AT 250 WORDS)     

Prevalence and Correlates of Sexual Partner Concurrency Among Australian Gay Men Aged 18–39 Years

Mathematical models predict higher rates of HIV and sexually transmitted infections (STIs) in populations with higher rates of concurrent sexual partnerships. Although gay men and other men who have sex with men (MSM) have disproportionately high rates of HIV/STIs, little is known about the prevalence and correlates of sexual concurrency in these populations. This paper reports findings from a national community-based survey of 1,034 Australian gay-identified men aged 18–39 years, who gave detailed information about their sexual partners over the past 12 months. In all, 237 (23 %) reported two or more concurrent sexual partners. For their most recent period of concurrency, 44 % reported three or more partners and 66 % reported unprotected sex with one or more of their partners. A multivariate logistic regression found sexual concurrency was significantly more likely among men on higher incomes (P = 0.02), who first had anal sex at a relatively young age (P = 0.03), and who reported a large number of partners in the past 12 months (P < 0.001). Age, education, HIV status, and other sociodemographic and sexual behavior variables were not significant correlates. However, men who reported sexual concurrency were significantly more likely to have been diagnosed with an STI in the past 12 months (P = 0.04). Findings from this study suggest sexual concurrency is common among younger Australian gay men. With many of these men not always using condoms, health agencies should consider the potential impact of concurrency on HIV/STI epidemics among gay men and other MSM.     

Dopamine transporter binding in social anxiety disorder: the effect of treatment with escitalopram

Social anxiety disorder (SAD) is characterised by fear of social or performance situations where the individual is exposed to unfamiliar people or to possible scrutiny by others. The literature on dopamine ligands and dopamine genotypes in SAD is however inconsistent. In this study we measured the effects of SSRI pharmacotherapy on dopamine transporter (DAT) binding in patients with SAD, also addressing variability in DAT genotype. Adult subjects meeting DSM-IV criteria for generalised SAD were studied before and after 12 weeks of pharmacotherapy with the selective serotonin reuptake inhibitor (SSRI) escitalopram. DAT single photon emission computed tomography (SPECT) using ¹²³I-FP-CIT was performed at baseline, and repeated at 12 weeks. Striatal DAT binding was analysed for changes following therapy, and for correlations with clinical efficacy, in the whole group as well as for a subgroup with the A10/A10 DAT genotype. The study included 14 subjects (9 male, 5 female) with a mean (SD) age of 41 (±13) years. The subjects’ Liebowitz Social Anxiety Scale (LSAS) score was significantly decreased following pharmacotherapy. In the combined group the left caudate and left putamen showed clusters of increased DAT binding after therapy. The left caudate changes were also observed in the subgroup of 9 A10/A10 homozygotes. However no correlation was found between improved symptoms and DAT binding. The changes found in DAT binding in the caudate and putamen may be due to serotonergic activation of dopamine function by SSRI therapy. This is consistent with previous work indicating decreased DAT binding in SAD, and increased DAT binding after SSRI administration.     

Exercise self-efficacy of postmenopausal women resident in the tropics

OBJECTIVES: Weight gain and the associated increased risk of coronary artery disease are associated with the postmenopausal period. However, moderate intensity physical activity may be cardioprotective in this period. Australian women remain predominately sedentary despite the health benefits of regular exercise. Self-efficacy is an important predictor of exercise behaviour influencing exercise adoption when faced with potential barriers. Determination of exercise self-efficacy levels and the most significant barriers to exercise is necessary for the success of intervention programs for this population. METHODS: Postmenopausal women (N=101) resident in tropical North Queensland were recruited via announcements in local media, service club newsletters and electronic bulletin boards. Following data collection, participants were categorised as exercisers (n=53) or non-exercisers (n=48) based on whether they had performed a minimum of 150 min of accumulated moderate intensity exercise in the past 7 days. Exercise self-efficacy was determined via questionnaire. RESULTS: Results indicated that exercisers had a higher level of exercise self-efficacy and felt significantly more confident to exercise when faced with barriers compared to non-exercisers (p<.001). Discriminant function analysis found that exercise self-efficacy provided the greatest discrimination between exercisers and non-exercisers. The barrier items of conflicting schedules, difficulty getting to an exercise location and the weather were the main contributors to discrimination between exercisers and non-exercisers. CONCLUSIONS: Findings suggest that future intervention programs should aim to increase exercise self-efficacy and address these barriers so that more postmenopausal women resident in North Queensland can obtain the health benefits of exercise.