Systematic case finding for tuberculosis in HIV-infected people who inject drugs: experience from Pakistan.

SETTING: Pakistan is a high tuberculosis (TB) burden country, moving from low human immunodeficiency virus (HIV) prevalence to a concentrated epidemic driven primarily by people who inject drugs (PWID). The Antiretroviral Treatment Adherence Unit (AAU) in Islamabad, Pakistan, is a residential facility that offers combined treatment for opioid dependence and HIV. OBJECTIVE AND DESIGN: This retrospective study was conducted to assess TB prevalence among HIV-infected PWID referred to the AAU and to evaluate the diagnostic value of cough as a screening symptom. A single sputum sample was collected regardless of symptoms, and examined using smear, Xpert® MTB/RIF and culture. RESULTS: Of 888 PWID, 71.5% submitted a sputum sample. More TB cases were detected using Xpert (n = 25) than with smear (n = 10) or culture (n = 20). A TB prevalence of 6141 per 100 000 was estimated based on seven cases already identified as being on anti-tuberculosis treatment and 32 newly diagnosed bacteriologically confirmed TB cases. Both cough and smoking (10 pack-years) were associated with increased TB prevalence. Only half of the TB cases reported cough. Rifampicin resistance was reported among 10% (3/29) of newly identified cases. CONCLUSION: TB prevalence in HIV-infected PWID was 15 times higher than in the general adult population. As a screening symptom, cough has low diagnostic value.

Use of image-guided bone scalpel for resection of spine tumors: technical note.

In the literature, the use of navigation for spine tumor surgery has largely centered on implant placement. We describe the cases of two patients with spinal tumors on whom we utilized our resection technique of registering an ultrasonic bone scalpel (UBS) to a navigation system. In both cases, we achieved a satisfactory tumor resection with negative margins and excellent neurologic outcomes. We feel that using the navigation-registered UBS is a valuable tool to increase the operator's ability to achieve desired resections while minimizing the neurologic deficits and operative morbidity associated with these challenging surgical cases.

Simulations of a dielectrophoretic membrane filtration process for removal of water droplets from water-in-oil emulsions.

A novel separation technique based on simultaneous application of AC dielectrophoresis and preferential transport through a semipermeable hydrophilic membrane is proposed for separation of small amounts of emulsified water droplets from a water-in-oil emulsion. Embedding an array of parallel microelectrodes on a membrane matrix, followed by application of an AC potential to these electrodes, can result in capturing the water droplets onto the membranes from the emulsion during a crossflow filtration process. The present paper describes the theoretical principles underlying such a process, and describes a simple mathematical framework based on trajectory analysis for assessing the separation efficiency of such a technique. The results indicate that superimposition of an AC dielectrophoretic field can significantly enhance the preferential transport of the emulsified water through the membrane in a crossflow filtration device. This can lead to a highly efficient continuous separation process for dilute emulsions.

Influence of limb length on a stepping exercise.

The effect of limb length on responses to the step-test exercise was studied in 10 subjects of various heights; oxygen consumption values served as an indicator. Mean oxygen consumption was found to be significantly related to limb length in the step-test exercise. This was demonstrated when subjects with different limb lengths were tested as a standard work load (i.e., 10 m/min x body wt) but at seven different bench heights and correspondingly adjusted stepping rates. The minimum values for oxygen consumption were obtained when the bench height was near 50% (45-55%) of subject's limb length.