Sampling Males Who Inject Drugs in Haiphong,Vietnam: Comparison of Time-Location and Respondent-Driven Sampling Methods

Accurate measurements of HIV prevalence and associated risk factors among hidden and high-risk groups are vital for program planning and implementation. However, only two sampling methods are purported to provide representative estimates for populations without sampling frames: time-location sampling (TLS) and respondent-driven sampling (RDS). Each method is subject to potential biases and questionable reliability. In this paper, we evaluate surveys designed to estimate HIV prevalence and associated risk factors among people who inject drugs (PWID) sampled through TLS versus RDS. In 2012, males aged ≥16 years who reported injecting drugs in the previous month and living in Haiphong, Vietnam, were sampled using TLS or RDS. Data from each survey were analyzed to compare HIV prevalence, related risk factors, socio-demographic characteristics, refusal estimates, and time and expenditures for field implementation. TLS (n = 432) and RDS (n = 415) produced similarly high estimates for HIV prevalence. Significantly lower proportions of PWID sampled through RDS received methadone treatment or met an outreach worker. Refusal estimates were lower for TLS than for RDS. Total expenditures per sample collected and number of person-days of staff effort were higher for TLS than for RDS. Both survey methods were successful in recruiting a diverse sample of PWID in Haiphong. In Vietnam, surveys of PWID are conducted throughout the country; although the refusal estimate was calculated to be much higher for RDS than TLS, RDS in Haiphong appeared to sample PWID with less exposure to services and required fewer financial and staff resources compared with TLS.     

An efficient access to β-ketosulfones via β-sulfonylvinylamines: metal–organic framework catalysis for the direct C–S coupling of sodium sulfinates with oxime acetates

A copper-based framework Cu₂(OBA)₂(BPY) was synthesized and used as a recyclable heterogeneous catalyst for the synthesis of β-sulfonylvinylamines from sodium sulfinates and oxime acetates via direct C–S coupling reaction. The transformation was remarkably affected by the solvent, and chlorobenzene emerged as the best option. This Cu-MOF displayed higher activity than numerous conventional homogeneous and MOF-based catalysts. The catalyst was reutilized many times in the synthesis of β-sulfonylvinylamines without considerably deteriorating in catalytic efficiency. These β-sulfonylvinylamines were readily converted to the corresponding β-ketosulfones via a hydrolysis step with aqueous HCl solution. To the best of our knowledge, this direct C–S coupling reaction to achieve β-sulfonylvinylamines was not previously conducted with a heterogeneous catalyst.

Cu₂(OBA)₂(BPY) was used as catalyst for the synthesis of β-sulfonylvinylamines from sodium sulfinates and oxime acetates. These β-sulfonylvinylamines were readily converted to corresponding β-ketosulfones via a hydrolysis step.     

Effect of Brain CYP2B Inhibition on Brain Nicotine Levels and Nicotine Self-Administration

The CYP2B enzyme is expressed in human and rat brain, and metabolizes many CNS-acting drugs. The gene that encodes human CYP2B6 is highly polymorphic, where the variation in brain enzyme levels could result in altered brain drug levels. CYP2B can metabolize nicotine, the main psychoactive ingredient in cigarettes; if altered brain CYP2B activity can influence nicotine brain levels, it could influence nicotine-mediated behaviors. To investigate this, a mechanism-based inhibitor selective for CYP2B, C8-xanthate (20 μg), was administered intracerebroventricularly (ICV) into the brain of rats, and 22 h later, nicotine levels were measured by in vivo microdialysis following nicotine (150 μg/kg intravenous). Brain nicotine levels from 15 to 30 min and the AUC_0–45min were both twofold higher (p<0.05) with C8-xanthate vs vehicle pretreatment; there was no difference in peripheral nicotine levels. Rats were then given ICV pretreatment with C8-xanthate/ASCF and underwent intravenous nicotine self-administration with 3.75–30 μg/kg per infusion dose. C8-xanthate pretreatment increased responding in progressive ratio (15 μg/kg per infusion dose, p<0.05). In a separate cohort, C8-xanthate increased the percentage of rats that acquired self-administration (7.5 μg/kg per infusion dose, p<0.05) from 40% after vehicle pretreatment to 100%, with no difference in peripheral nicotine levels measured at the end of behavior. In a third cohort, C8-xanthate increased the number of sessions required to meet extinction criteria (p<0.05). Together these data demonstrate that the brain CYP2B activity can influence nicotine brain levels and subsequent behaviors independent of hepatic metabolism. This suggests that human smokers with variable CYP2B brain levels could have different nicotine levels and reinforcement, which might have a role in smoking behaviors and dependence.     

Pharmacokinetics of the antimalarial drug piperaquine in healthy Vietnamese subjects

We compared plasma maximum concentration (Cmax) and area under the concentration-time curve (AUC) of the antimalarial drug piperaquine in 26 healthy Vietnamese subjects after treatment with either a single oral dose of 500 mg (n = 6) or 1,000 mg (n = 6) of piperaquine phosphate and a three-day course of 500 mg of piperaquine/ day in the fasting state (n = 7) or with food (approximately 17 g fat) (n = 7). The geometric mean plasma Cmax and AUC((0-28)) was 2.8-fold (200 ng/mL versus 70 ng/mL) and 1.9-fold (5,736 ng x h/mL versus 2,999 ng x h/mL), respectively, and higher in subjects receiving the 1,000-mg dose than in those receiving the 500-mg dose. The geometric mean Cmax and AUC((0-28)) was 1.7-fold (198 ng/mL versus 119 ng/mL) and 1.4-fold (11,187 ng x h/mL versus 7,954 ng x h/mL) higher in the fed state than in the fasting state. Piperaquine AUC was proportional to the two doses tested and a moderate-fat meal enhanced the bioavailability of piperaquine by 41%, which should improve the therapeutic efficacy of this drug.     

Impaired oxygenation of gastric mucosa in portal hypertension

Increased susceptibility to mucosal damage is a prominent feature of portal hypertensive gastropathy. Since the portal hypertensive gastric mucosa has extensive microvascular changes, we postulated that the increased sensitivity to mucosal damage could have an ischemic basis. We measured distribution of gastric serosal and mucosal oxygenation in a group of portal hypertensive and sham-operated rats, and then studied the effects of intragastric aspirin. In the basal state, gastric mucosa of portal hypertensive rats had significantly reduced oxygenation compared to controls (24±5 vs 45±7 mm Hg PO ₂,P < 0.02), while serosal oxygenation was similar between the two groups. Intragastric aspirin produced significantly greater mucosal damage to portal hypertensive rats and mucosal oxygenation was almost one third that of sham-operated controls. Systemic arterial pressures and oxygenation were similar between the two groups. We conclude that there is impairment of gastric mucosal oxygenation and increased mucosal damage by aspirin in portal hypertensive rats compared with sham-operated controls. These results support our hypothesis that the increased sensitivity of the portal hypertensive mucosa to damage is a consequence of impaired mucosal oxygenation.This study was supported by the Veterans Administration Research Service.This work was presented, in part, at the Plenary Session of the American Association for the Study of Liver Diseases, May 1988, New Orleans, Louisiana.     

Predictors of angiographic restenosis after coronary intervention in patients with diabetes mellitus

Background

Patients with diabetes mellitus are particularly prone to restenosis after percutaneous coronary intervention. An exploratory, nested, case-control study was undertaken to identify clinical, lesional, and procedural predictors of angiographic restenosis in these patients.

Methods

Seventy-five patients with diabetes mellitus with 86 coronary lesions were selected from a larger population of 217 patients who had undergone 6-month angiographic follow-up after a first, successful balloon angioplasty (PTCA) or stent implantation procedure. Data collection was by patient interview and review of hospital database and other medical records. All angiograms were analyzed with quantitative coronary angiography, and restenosis was defined as a ≥50% diameter reduction at the treated site. A multivariate analysis of 10 prespecified explanatory variables, derived from a literature review, was performed on a per-lesion basis.

Results

There were 45 patients (53 lesions) with restenosis and 30 patients (33 lesions) without restenosis. Univariate predictors of binary restenosis were periprocedural glycosylated hemoglobin level, vessel reference diameter, PTCA, and larger final balloon size to reference artery diameter ratio. Multiple logistic regression identified poor glycemic control (odds ratio [OR] 3.03, 95% CI 1.06-8.65, P = .038), small vessel reference diameter (OR 3.41, 95% CI 1.17-9.95, P = .025), and mode of intervention (OR 3.12, 95% CI 1.08-9.00, P = .036) as independent risk factors. Vessel reference diameter appeared to be an important effect modifier of the association between type of intervention and angiographic outcome, with stenting no longer superior to PTCA in patients with diabetes mellitus who had vessels <2.87 mm in diameter (P = .054).

Conclusion

Poor glycemic control, vessel size, and PTCA were independent predictors of restenosis in patients with diabetes mellitus. It is possible that improved periprocedural glycemic control, in addition to stenting, may reduce the restenosis rate in these patients.     

Population-based chest X-ray screening for pulmonary tuberculosis in people living with HIV/AIDS, An Giang, Vietnam.

SETTING: Human immunodeficiency virus/acquired immune-deficiency syndrome (HIV/AIDS) program, An Giang Province, Vietnam. OBJECTIVE: To evaluate the coverage and yield of a chest radiography (CXR) screening program for tuberculosis (TB) among people living with HIV/AIDS (PLHA), risk factors for a TB CXR, inter-rater reliability of CXR readings and direct costs. DESIGN: Retrospective review of routine public health program records and CXRs. RESULTS: An increasing proportion of PLHAs received a screening CXR each year of the program (range 21% in 2001 to 61% in 2004, P<0.001). Of 876 screening CXRs performed, 191 (22%) were classified as suspicious for active TB ('TB CXR'). Compared to PLHAs with a CXR not suspicious for active TB, PLHAs with a TB CXR were more likely to be aged between 24 and 64 years, male and previously treated for TB (P<0.01 for each comparison). Agreement between the expert and local program CXR readings was 81% (kappa 0.50). Direct costs were approximately US$40 per TB suspect identified. Among TB suspects, <10% were followed up with sputum smear examination and enrolled for treatment. CONCLUSION: In An Giang Province, a large proportion of PLHAs are screened for TB annually, and one in five persons screened is classified as a TB suspect based on CXR. Annual CXRs may be a high-yield, inexpensive method for TB screening in PLHAs, but the follow-up of TB suspects to confirm diagnosis and initiate treatment is crucial.     

A Posttraumatic Dilated,Proptotic Eye Does Not Always Need a Lateral Canthotomy! A Review of Superior Orbital Fissure Syndrome for Emergency Physicians

BackgroundSuperior orbital fissure syndrome (SOFS) is a rare constellation of findings consisting of ophthalmoplegia, ptosis, a fixed dilated pupil, forehead anesthesia, and loss of the corneal reflex. This syndrome, though rare, is most often encountered in trauma with individuals sustaining a facial fracture.Case ReportWe present a case of a young woman who was diagnosed with SOFS after a fall in her house, hitting her face on a nightstand. Treatment consisted of high-dose i.v. steroids followed by a taper with close follow-up in the Ophthalmology clinic. We provide a brief review of SOFS, including treatment considerations and follow-up.Why Should an Emergency Physician Be Aware of This?SOFS can be easily overlooked in an individual presenting to the emergency department after facial trauma with proptosis. However, a thorough examination of the eye, visual acuity, and intraocular pressure will focus the physician on SOFS rather than the need for immediate decompression via lateral canthotomy. This report describes a traumatic cause of SOFS, the pathophysiology and treatment, and summarizes existing literature.