High risk sexual behaviours among heroin sniffers who have no history of injection drug use: implications for HIV risk reduction.

The purpose of this paper is to assess sexual behaviours which place heroin sniffers (HSs) at high risk for HIV infection. A stratified network-based sample was used to recruit HSs who had no history of injection drug use was recruited from the streets of South Florida, USA. HSs displayed a high HIV seroprevalence rate of 12.1%; women (18.1%) were more likely than men (8.7%) to test positive for HIV. Both men and women HSs engaged in considerable high risk sex behaviour, including high risk sex-exchange behaviour. The use of crack cocaine was associated with increased sex exchange behaviour among women. The need for intervention programs targeted toward HSs is discussed.

Primary preventive health care among injection drug users, other sustained drug users, and non-users.

The primary objective of this paper is to investigate the relationship between sustained illicit drug use and the utilization of primary preventive health care. Data from 1254 African-American, Hispanic/Latino, and non-Hispanic/Latino white men and women collected in 1996-1997 were analyzed to determine independent risk factors for the utilization of primary preventive health care that was not received as a result of seeking treatment for a specific health condition. When several demographic, health, and drug use variables were assessed in a logistic regression model, gender, ethnicity, health insurance status, drug use, and alcohol use were independently associated with primary preventive care. Women, Hispanic/Latinos, and persons who had health insurance were more likely to have received primary preventive health care while injection drug users, other sustained drug users, and "heavy" alcohol users were less likely to have used primary preventive health care services in the past year.

A comparison of HIV risk behaviors between new and long-term injection drug users.

The purpose of this study was to characterize the injection and sexual risk behaviors of a cohort of active drug injectors who have initiated injection within the past 4 years and to compare their behaviors with the risk behaviors of long-term injectors who have been injecting drugs since 1984. A stratified, network-based sample was used to recruit injection drug users from the streets in Miami-Dade, Florida. After screening for eligibility, which included a urine test to confirm current drug use, participants were administered a structured questionnaire that included basic demographic information, drug-use history, and HIV risk behavior practices. Both injector groups displayed a high level of HIV injection risk behavior. Although new initiates into injection demonstrated lower risk behavior than long-term injectors at the first injection episode, the current risk behavior between new and long-term injectors is similar.

Functional stability re-training: principles and strategies for managing mechanical dysfunction.

Functional stability is dependent on integrated local and global muscle function. Mechanical stability dysfunction presents as segmental (articular) and multi-segmental (myofascial) dysfunction. These dysfunctions present as combinations of restriction of normal motion and associated compensations (give) to maintain function. Stability dysfunction is diagnosed by the site and direction of give or compensation that relates to symptomatic pathology. Strategies to manage mechanical stabililty dysfunction require specific mobilization of articular and connective tissue restrictions, regaining myofascial extensibility, retraining global stability muscle control of myofascial compensations and local stability muscle recruitment to control segmental motion. Stability re-training targets both the local and global stability systems. Activation of the local stability system to increase muscle stiffness along with functional low-load integration in the neutral joint position controls segmental or articular give. Global muscle retraining is required to correct multisegmental or myofascial dysfunction in terms of controlling the site and direction of load that relates to provocation. The strategy here is to train low-load recruitment to control and limit motion at the site of pathology and then actively move the adjacent restriction, regain through range control of motion with the global stability muscles and regain sufficient extensibility in the global mobility muscles to allow normal function. Individual strategies for integrating local and global recruitment retraining back into normal function are suggested.

Movement and stability dysfunction--contemporary developments.

A good understanding of the control processes used to maintain stability in functional movements is essential for clinicians who attempt to treat or manage musculoskeletal pain problems. There is evidence of muscle dysfunction related to the control of the movement system. There is a clear link between reduced proprioceptive input, altered slow motor unit recruitment and the development of chronic pain states. Dysfunction in the global and local muscle systems is presented to support the development of a system of classification of muscle function and development of dysfunction related to musculoskeletal pain. The global muscles control range of movement and alignment, and evidence of dysfunction is presented in terms of imbalance in recruitment and length between the global stability muscles and the global mobility muscles. Direction related restriction and compensation to maintain function is identified and related to pathology. The local stability muscles demonstrate evidence of failure of adequate segmental control in terms of allowing excessive uncontrolled translation or specific loss of cross-sectional area at the site of pathology. Motor recruitment deficits present as altered timing and patterns of recruitment. The evidence of local and global dysfunction allows the development of an integrated model of movement dysfunction.

First injection and current risk factors for HIV among new and long-term injection drug users.

The purpose of this paper is to estimate HIV seroprevalence and to examine the injection and sexual risk behaviours of a cohort of active new heroin injectors who have initiated injection within the past four years and to compare their risk behaviours with those of long-term heroin injectors who initiated injection prior to January 1, 1985. A stratified network-based sample was used to recruit injection drug users (IDUs) from the streets of Miami-Dade, Florida. New IDUs displayed a significantly lower HIV seroprevalence than long-term injectors (13.3 versus 24.7%). Both new and long-term drug injectors exhibited a high level of current HIV risk behaviour. While new injectors were more likely than long-term injectors to practise safer injection behaviours at the initial injection episode, the current risk behaviours of new and long-term injectors are similar.

Health care need and utilization: a preliminary comparison of injection drug users, other illicit drug users, and nonusers.

This paper investigates the relationship between chronic drug use and the health care system. Data from 536 African-American, Hispanic, and non-Hispanic White men and women were analyzed to determine independent risk factors for three outcome variables: 1) Need for health care treatment, 2) Utilization of health care treatment, and 3) Failure to receive needed treatment. Nine independent demographic, health, and drug-use history variables were assessed in logistic regression models. Chronic drug users were more likely in the past year to need health care treatment, were as likely to receive some health care treatment, and were more likely not to receive needed treatment than were nonusers.

Safe epidural analgesia in thirty parturients with platelet counts between 69,000 and 98,000 mm(-3).

Regional anesthesia is a popular form of pain relief for the management of labor and delivery. Thrombocytopenia is considered a relative contraindication to the administration of regional anesthesia. Some authorities have recommended that an epidural anesthetic be withheld if the platelet count is <100,000 mm(-3). For the period of March 1993 through February 1996, we reviewed the charts of all parturients who had a platelet count <100,000 mm(-3) during the peripartum period. Eighty women met this criterion. Of these 80, 30 had an epidural anesthetic placed when the platelet count was <100,000 mm(-3) (range 69,000-98,000 mm(-3)), 22 had an epidural anesthetic placed with a platelet count >100,000 mm(-3) that subsequently decreased below 100,000 mm(-3), and 28 did not receive a regional anesthetic. We found no documentation of any neurologic complications in the medical records. We conclude that regional anesthesia should not necessarily be withheld when the platelet count is <100,000 mm(-3).

Role of inducible nitric oxide synthase in pharmacological "preconditioning" with monophosphoryl lipid A.

Pretreatment with monophosphoryl lipid A (MLA) can pharmacologically mimic the second window of ischemic preconditioning (SWOP) to protect the heart from prolonged ischemia and reperfusion injury. Based on the delayed time course for development of MLA associated cardioprotection, this study was designed to test if MLA's cardioprotective effect is mediated by signalling through production of inducible nitric oxide synthase (iNOS), a proposed effector of SWOP. Rabbits were assigned to one of four groups: (1) vehicle control; (2) MLA: (3) vehicle+aminoguanidine (AMG) control; or (4) MLA+AMG. Monophosphoryl lipid A (35 micrograms/kg) or vehicle was given intravenously 24 h before ischemia. The selective iNOS inhibitor AMG (300 mg/ kg) was injected subcutaneously 1 h before ischemia. All rabbits experienced 30 min coronary artery occlusion followed by 3 h of reperfusion. Infarct size was measured by triphenyltetrazolium chloride (TTC) staining. followed by 3 h of reperfusion. Infarct size was measured by triphenyltetrazolium chloride (TTC) staining. Myeloperoxidase activity, an index of neutrophil infiltration, was also quantified in heart tissue collected from the post-ischemic viable border zone surrounding the infarct area. MLA pretreatment significantly reduced infarct size and neutrophil infiltration in rabbit hearts compared to control (P < 0.05). Inhibition of iNOS activity by AMG abolished the infarct size reductive effect of MLA. Aminoguanidine also blocked the ability of MLA to significantly reduce neutrophil infiltration. Although measurement of iNOS activity did not show induction of the enzyme in normal myocardial tissue 24 h after MLA pretreatment, an increase in iNOS activity in ischemic tissue relative to non-ischemic tissue was found after either 15 or 30 min of coronary occlusion in MLA treated rabbits. These results suggest that MLA pretreatment may enhance iNOS enzyme activity by MLA during ischemia which may be responsible for the observed cardioprotection.

Myocardial ischemia/reperfusion protection using monophosphoryl lipid A is abrogated by the ATP-sensitive potassium channel blocker, glibenclamide.

OBJECTIVES: Monophosphoryl lipid A (MLA), a detoxified derivative of the lipid A portion of the endotoxin molecule, given as a pretreatment 24 h prior to cardiac ischemia/reperfusion reduces myocardial stunning and infarction in dogs. This study was undertaken to evaluate the ability of MLA pretreatment to reduce infarct size in a rabbit model of in situ regional myocardial ischemia and reperfusion. Secondly, the potential role of modulation of ATP-sensitive potassium (KATP) channel in MLA's cardioprotection was evaluated using in vivo pharmacologic antagonism with a KATP channel blocker, as was the role of tumor necrosis factor using an enzyme-linked immunosorbent assay method of serum cytokine analysis. METHODS: Rabbits were pretreated intravenously with MLA or vehicle injection 24 h prior to initiation of 30 min in situ left anterior descending coronary artery occlusion followed by 3 h reperfusion. In animals receiving glibenclamide, the potassium channel antagonist was administered 30 min prior to inducing ischemia. Animals receiving glibenclamide, which possesses hypoglycemic effects, underwent serial blood glucose evaluation prior to drug and throughout the ischemia and reperfusion periods. Hemodynamics were monitored; infarct size and area at risk were assessed by contrast dye staining (triphenyltetrazolium chloride). Serum tumor necrosis factor was measured by enzyme-linked immunosorbent method in animals administered cardioprotective doses of MLA as well as pyrogenic doses of MLA and endotoxin (positive control) to determine if elaboration of this cytokine could be associated with the cardioprotective effect of MLA. RESULTS: MLA administered as a single intravenous dose 24 h prior to ischemia reduced infarct size, expressed as a percent of the area at risk, 64 and 71% at doses of 35 and 10 micrograms/kg, respectively. Lower doses of MLA (2.5 and 5 micrograms/kg) did not significantly reduce infarct size. Administration of glibenclamide (300 micrograms/kg) 30 min prior to ischemia completely blocked the ability of MLA pretreatment to limit infarct size, while MLA vehicle-glibenclamide-treated control rabbits displayed infarcts not significantly different from MLA-vehicle-treated control rabbits. A cardioprotective dose of MLA (35 micrograms/kg) did not induce the elaboration of tumor necrosis factor into rabbit serum (within the limits of assay sensitivity). CONCLUSIONS: Single-dose pretreatment with MLA administered intravenously to rabbits substantially reduces infarct size when administered 24 h prior to ischemia. Pharmacologic preconditioning with MLA appears to be mediated through KATP channels as the channel blocker, glibenclamide, reversed the cardioprotective activity of MLA when administered 1 day following MLA pretreatment, yet 30 min prior to ischemia. In this model the cardioprotective does not appear to be associated with increases in serum tumor necrosis factor.

Risk factors for HIV-1 seroconversion among injection drug users: a case-control study.

OBJECTIVES: A nested case-control study was conducted in Miami, Fla, to determine risk factors associated with human immunodeficiency virus type 1 (HIV-1) seroconversion among injection drug users. METHODS: The study identified 21 incident cases of HIV-1 infection and 76 unmatched controls from two longitudinal cohorts of injection drug users. One cohort consisted of individuals who originally had been recruited from treatment centers; a second cohort was recruited from the "street." Logistic regression analyses that adjusted for age, gender, and race were performed. RESULTS: The final model determined that the primary independent risk factor that best explained the risk for seroconversion was sharing injection equipment in the year prior to conversion; a marginal risk factor was presence of sexually transmitted disease during this same period. CONCLUSIONS: Both an injection component and a sexual component play a role in seroconversion among injection drug users, although the injection component is much stronger.

The consistency of self-reported HIV risk behavior among injection drug users.

OBJECTIVES: Most studies of risk factors for human immunodeficiency virus (HIV) rely heavily on retrospective self-reports. The degree to which these reports provide reliable information has received little research attention. The purpose of this study was to assess the extent to which the reliability of retrospective self-report data is affected over time. METHODS: Data were examined from a longitudinal study of risk behaviors among injection drug users. Structured interviews were administered to 366 injection drug users who were asked to recall behaviors that they had reported 6, 12, or 18 months earlier. RESULTS: Kappa coefficients showed moderate initial memory loss for injection and sexual risk behaviors. After 6 months, time had little effect on the ability of injection drug users to recall injection and sexual risk behaviors. For ordinal measures of risk, subjects who gave different reports over time were most likely to disagree by one response category. CONCLUSIONS: These findings support the use of retrospective self-reports in assessing HIV risk behaviors among injection drug users. Retrospective inquiry is likely to remain an important method for collecting data over time.

Towards a measurement of active muscle control for lumbar stabilisation.

No measure described to date reflects the ability of muscles to stabilise the lumbar spine. A static model was developed in supine crook lying, to measure active rotatory control with trunk loading in the sagittal plane via low, unilateral leg load. The hypothesis was that excessive lumbar movement indicates an inability of the stabilising muscles to automatically co-ordinate appropriate muscle force to support the spine. A computerised sensor was developed to monitor lumbar positional change. A rotatory stability index was calculated from pressure variations on taking leg load. Preliminary trials showed that this static model identified individuals with poor active rotatory control. Further development of the measurement model is warranted.

Acoustic myography of the human quadriceps muscle during intermittent fatiguing activity.

Integrated acoustic myography (IAMG) and electromyography (IEMG) were recorded over rectus femoris (RF) in six healthy subjects during a series of intermittent isometric contractions of quadriceps. Contractions were held for 10 sec with 10 sec rest between each, commencing at 75% maximum voluntary contraction (MVC) force and continuing to 40% MVC. The IAMG activity initially decreased (75%-60% MVC) in a linear relationship (r = 0.9) with fatigue (i.e. force loss) but then plateaued and increased once force fell below 52% MVC. The AMG/force relationship for the whole fatiguing protocol (i.e. 75%-40% MVC) was quadratic (r = 0.87). The IEMG also showed a quadratic relationship with force (r = 0.85) but activity initially increased before decreasing. The results of the present study quantify the relationship between AMG and force in quadriceps during fatigue from intermittent contractions commencing at 75% MVC. The findings confirm previous observations that AMG decreases with fatigue during strong contractions but the quadratic relationship found in the present study differs to that for other muscles during sustained contractions. The results also suggest that simultaneous recordings of AMG and EMG may help distinguish central and peripheral fatigue. Acoustic myography may therefore be a useful non-invasive monitor of force during early fatiguing activity using the present protocol but the need to study AMG during fatigue of different muscles and force levels is stressed.

Techniques for active lumbar stabilisation for spinal protection: A pilot study.

Active protection of the lumbar spine is important in prevention of back strain during exercise. This EMG study investigated three common techniques used for lumbar stabilisation : posterior pelvic tilt, lower abdominal hollowing with lumbar spine flattening and abdominal bracing. The aim was to determine which method encouraged the best stability pattern. Muscle activity was measured in obliquus abdominis, upper and lower rectus abdominis and the lumbar erector spinae. Standardisation of muscle activity against that during maximally resisted trunk rotation (already shown to illustrate an appropriate stability pattern) allowed comparisons between exercise techniques in relation to their stabilisation pattern. Results indicated that posterior pelvic tilt demonstrated the least desirable stability pattern. Both abdominal hollowing and bracing provided a more suitable pattern.

The donation and sale of blood by intravenous drug users.

In spite of efforts to dissuade intravenous drug users (IVDUs) from donating or selling blood, some continue to do so. As part of a longitudinal study, 915 IVDUs in South Florida were interviewed concerning their history of donation or sale of blood and tested for antibodies to HIV-1 and HTLV-I/II. Approximately 17 percent had either donated or sold blood during 1985 through 1988; most contributors (80.4 percent) sold to commercial blood services. IVDUs who had donated/sold blood were more likely to be male and not in drug treatment than were those who had not contributed blood. IVDUs not in treatment at the time of interview were more likely than IVDUs in treatment to have sold blood. Of those who had donated/sold blood since 1985, 19.6 percent subsequently tested positive for antibodies to HIV-1 and 5.7 percent were positive for antibodies to HTLV-I/II. Increased effort is required to screen prospective donors and sellers, particularly at commercial blood banks.

The relationship between exercise tolerance and quality of life in angina pectoris.

The relationship between exercise tolerance assessed by a conventional exercise stress test using a standard Bruce protocol and quality of life (QoL) was studied in 50 patients with stable angina pectoris (AP). Before the exercise test, patients completed three self-administered QoL questionnaires, the Psychological General Well-Being Index, an Angina-Specific QoL Questionnaire, and Jenkins' Sleep Dysfunction Scale. Total exercise time (r = -0.40) and time until onset of pain (r = -0.44) were significantly correlated with perceived physical limitations. Somatic symptoms were related to total time (r = -0.38). Apart from a significant correlation between depressed mood and total exercise time (r = 0.36), there was no corresponding correlation with well-being and sleep disturbance. These results suggest that exercise stress tests do not reflect quality of life in patients with AP.