Sexual risk among injection drug users recruited from syringe exchange programs in California

OBJECTIVE: The objective of this study was to examine correlates of sexual risk among injection drug users (IDUs). STUDY: A total of 1445 IDUs were recruited from California syringe exchange programs. RESULTS: Consistent condom use was independently related to being HIV-positive, having multiple sex partners, not having a steady partner, not sharing syringes, and not injecting amphetamines for men; and engaging in sex work, not sharing syringes, and not having a steady partner for women. Having multiple recent sexual partnerships that included a steady partner was related to engaging in sex work, speedball injection, and amphetamine use among men; and younger age, having had a sexually transmitted disease (STD), engaging in sex work, and using alcohol among women. Having heterosexual anal sex was related to having had an STD, having multiple sexual partners, using amphetamines, and syringe-sharing for men; and younger age and amphetamine use for women. CONCLUSIONS: Comprehensive prevention interventions addressing multiple sexual and injection risk behaviors are needed for IDUs.     

Metabolic and cardiovascular effects of adrenaline and alprenolol (Aptin®) in human subjects

Summary Changes in blood pressure, heart rate, hematocrit, O₂ consumption, blood glucose, lactate, pyruvate and FFA during intravenous adrenaline infusion alone and after pre-treatment with alprenolol (Aptin^®), a beta-adrenergic receptor blocker, were studied in four healthy fasting male subjects according to double-blind technique with saline infusions as control. Adrenaline alone caused increases in heart rate, hematocrit and systolic blood pressure and a decrease in diastolic pressure. After alprenolol, adrenaline infusion gave a decrease in heart rate with an increase in both systolic and diastolic blood pressure, while the hematocrit was unchanged. The adrenaline infusion caused significant rises in all the metabolic variables studied. Pre-treatment with alprenolol abolished all these rises with the exception of blood glucose.     

Anodic Polarity Minimizes Facial Nerve Stimulation as a Side Effect of Cochlear Implantation

One severe side effect of the use of cochlear implants (CI) is coincidental facial nerve stimulation (FNS). Clinical methods to alleviate FNS range from the reprogramming of processor settings to revision surgery. We systematically assessed different changes in CI stimulation modes that have been discussed in the literature as “rescue factors” from FNS: electrode configuration (broad to focused), pulse shape (symmetric biphasic to pseudo-monophasic), and pulse polarity (cathodic to anodic). An FNS was assessed, based on electrophysiological thresholds, in 204 electrically evoked compound action potential (eCAP) input/output functions recorded from 33 ears of 26 guinea pigs. The stimulation level difference between auditory nerve eCAP threshold and FNS threshold was expressed as the eCAP-to-FNS offset. Coincidental FNS occurred in all animals and in 45% of all recordings. A change from monopolar to focused (bipolar, tripolar) configurations minimized FNS. The Euclidean distance between the CI contacts and the facial nerve explained no more than 33% of the variance in FNS thresholds. For both the FNS threshold and the eCAP-to-FNS offset, the change from cathodic to anodic pulse polarity significantly reduced FNS and permitted a gain of 14–71% of the dynamic range of the eCAP response. This “anodic rescue effect” was stronger for pseudo-monophasic pulses as compared to the symmetric biphasic pulse shape. These results provide possible mechanisms underlying recent clinical interventions to alleviate FNS. The “anodic-rescue effect” may offer a non-invasive therapeutic option for FNS in human CI users that should be tested clinically, preferably in combination with current-focusing methods.