Changes in patterns of drug use among injecting drug users following changes in the availability of heroin in New South Wales, Australia

The aim of this study was to examine changes in drug use patterns among groups of injecting drug users (IDU) who remained in the drug market during a period of reduced heroin availability in NSW, Australia. Cross-sectional data collected from regular IDU interviewed as part of the NSW Illicit Drug Reporting System (IDRS) between 1996 - 2003 were analysed. Drug use patterns, reported drug availability and price were assessed. There was a marked decrease in the frequency of heroin use during the period of reduced availability in 2001, with some increase in 2002 and 2003. Heroin availability and frequency of use have not returned to levels reported prior to 2001; however; even at the peak of the reduction in supply, users continued to access heroin. There was a significant shift among IDU from heroin to cocaine during 2001, which subsequently reversed. The availability of cocaine has fluctuated in recent years, but the price has remained stable. The price of heroin appeared to be more responsive to market fluctuations, and co-varied with heroin availability. IDU used cocaine when heroin was less available; however, patterns of cocaine use were not maintained. The frequency of heroin use remained lower, which may be indicative of a less consistent supply, increased price or increased numbers of IDU entering treatment. The reduced supply of heroin in 2001 highlighted the adaptable nature of IDU patterns of use, indicative of the need for a commensurate treatment response. It also highlighted the importance of the ongoing monitoring of drug trends in Australia. [Roxburgh A, Degenhardt L, Breen C. Changes in patterns of drug use among injecting drug users following changes in the availability of heroin in New South Wales, Australia. Drug Alcohol Rev 2004;23:287-294]     

Transitions in the concept of chronic pain

Chronic pain is a worldwide problem with significant physical, psychological, and social impacts. Despite its prevalence and cost, the phenomenon is not well understood. An inductive method of concept analysis was used to study the concept of chronic, non-cancerous pain in adults. A random sample of nursing, psychology, and neurophysiology literature published over a 30-year period (1969 through 1999) was used to generate a consensual definition of chronic pain. The transition in the attributes, antecedents, consequences, related concepts, and surrogate terms of chronic pain is described, and the implications of the findings for practice and research are discussed.     

A multicenter,randomized, controlled trial comparing bupivacaine with ropivacaine for labor analgesia

BACKGROUND: A meta-analysis of studies comparing high doses of bupivacaine with ropivacaine for labor pain found a higher incidence of forceps deliveries, motor block, and poorer neonatal outcome with bupivacaine. The purpose of this study was to determine if there is a difference in these outcomes when a low concentration of patient-controlled epidural bupivacaine combined with fentanyl is compared with ropivacaine combined with fentanyl. METHODS: This was a multicenter, randomized, controlled trial, including term, nulliparous women undergoing induction of labor. For the initiation of analgesia, patients were randomized to receive either 15 ml bupivacaine, 0.1%, or 15 ml ropivacaine, 0.1%, each with 5 microg/ml fentanyl. Analgesia was maintained with patient-controlled analgesia with either local anesthetic, 0.08%, with 2 microg/ml fentanyl. The primary outcome was the incidence of operative delivery. We also examined other obstetric, neonatal, and analgesic outcomes. RESULTS: There was no difference in the incidence of operative delivery between the two groups (148 of 276 bupivacaine recipients vs. 135 of 279 ropivacaine recipients; P = 0.25) or any obstetric or neonatal outcome. The incidence of motor block was significantly increased in the bupivacaine group compared with the ropivacaine group at 6 h (47 of 93 vs. 29 of 93, respectively; P = 0.006) and 10 h (29 of 47 vs. 16 of 41, respectively; P = 0.03) after injection. Satisfaction with mobility was higher with ropivacaine than with bupivacaine (mean +/- SD: 76 +/- 23 vs. 72 +/- 23, respectively; P = 0.013). Satisfaction for analgesia at delivery was higher for bupivacaine than for ropivacaine (mean +/- SD: 71 +/- 25 vs. 66 +/- 26, respectively; P = 0.037). CONCLUSIONS: There was no difference in the incidence of operative delivery or neonatal outcome among nulliparous patients who received low concentrations of bupivacaine or ropivacaine for labor analgesia.     

Percutaneous thrombin injection for the treatment of a post-pancreatitis pseudoaneurysm

Visceral artery pseudoaneurysms are often treated surgically or by transcatheter embolisation. We report a case of a pseudoaneurysm in a patient with chronic pancreatitis, which was successfully occluded by percutaneous injection of thrombin into the pseudoaneurysmal sac as a first-line management.     

Effect of Moisture on the Stability of a Lyophilized Humanized Monoclonal Antibody Formulation

Purpose. To determine the effect of moisture and the role of the glass transition temperature (T_g) on the stability of a high concentration, lyophilized, monoclonal antibody. Methods. A humanized monoclonal antibody was lyophilized in a sucrose/histidine/polysorbate 20 formulation. Residual moistures were from 1 to 8%. T_g values were measured by modulated DSC. Vials were stored at temperatures from 5 to 50°C for 6 or 12 months. Aggregation was monitored by size exclusion chromatography and Asp isomerization by hydrophobic interaction chromatography. Changes in secondary structure were monitored by Fourier transform infrared (FTIR). Results. T_g values varied from 80°C at 1% moisture to 25°C at 8% moisture. There was no cake collapse and were no differences in the secondary structure by FTIR. All formulations were stable at 5°C. High moisture cakes had higher aggregation rates than drier samples if stored above their T_g values. Intermediate moisture vials were more stable to aggregation than dry vials. High moisture samples had increased rates of Asp isomerization at elevated temperatures both above and below their T_g values. Chemical and physical degradation pathways followed Arrhenius kinetics during storage in the glassy state. Only Asp isomerization followed the Arrhenius model above the T_g value. Both chemical and physical stability at T T_g were fitted to Williams-Landel-Ferry (WLF) kinetics. The WLF constants were dependent on the nature of the degradation system and were not characteristic of the solid system. Conclusion. High moisture levels decreased chemical stability of the formulation regardless of whether the protein was in a glassy or rubbery state. In contrast, physical stability was not compromised, and may even be enhanced, by increasing residual moisture if storage is below the T_g value.