The major medical complications of heroin addiction

Inflammatory disorders that affect the cerebral small vessels

ABSTRACT

This comprehensive review synthesizes the latest advancements in understanding inflammatory disorders affecting cerebral small vessels, a distinct yet understudied category within cerebral small vessel diseases (SVD). Unlike classical SVD, these inflammatory conditions exhibit unique clinical presentations, imaging patterns, and pathophysiological mechanisms, posing significant diagnostic and therapeutic challenges. Highlighting their heterogeneity, this review spans primary angiitis of the central nervous system, cerebral amyloid angiopathy-related inflammation, systemic vasculitis, secondary vasculitis, and vasculitis in autoinflammatory diseases. Key discussions focus on emerging insights into immune-mediated processes, neuroimaging characteristics, and histopathological distinctions. Furthermore, this review underscores the importance of standardized diagnostic frameworks, individualized immunomodulation approaches, and novel targeted therapies to address unmet clinical demands.

Imaging Utilization and Cost of Substance Use in an Urban Academic Medical Center During the Contemporary Opioid Epidemic

RATIONALE AND OBJECTIVES

To determine the recent impact of illicit substance use on imaging utilization and associated costs.

METHODS

Retrospective study from an inner city urban multi-site academic medical center. Institutional Review Board (IRB) approval was obtained with a waiver of informed consent. A substance use cohort comprised patients 12 years old presenting to the Emergency Department (ED) January 2017 to June 2019 with a positive urine toxicology and an ICD code associated with substance use. The comparison cohort was randomly selected from a group of ED patients who presented with no or negative urine toxicology and no documented substance use ICD code. Data extracted from the EMR included demographics, number and type of imaging studies, Charlson comorbidity index, and in-hospital mortality during the study period.

RESULTS

The substance use and comparison cohorts comprised 3191 and 3200 patients, respectively. The substance use cohort was older on average (mean age 45.67 ± 14.88 vs 43.91 ± 20.57 years), more often male (63% [2026/3191] vs. 39% [1255/3200]) and had a mean Charlson score 88% higher than the comparison cohort (3.33 vs 1.78). The majority of both cohorts were ethnic minorities (<10% white). The substance use cohort had significantly more imaging vs the comparison cohort, total 36,413 (mean 11.41 exams/patient) vs total 12,399 (mean 3.87 exams/patient), p < 0.0001, and was higher for all modalities except mammography. Average imaging costs per patient were nearly 300% higher for the substance use vs comparison cohort, ($1287.18 vs. $434.70).

CONCLUSION

Imaging utilization and associated costs were substantially higher for patients with a positive urine toxicology and substance use related ICD codes compared to the broader ED population in an underserved urban population.

Headaches and Vasculitis

Vasculitis refers to heterogeneous clinicopathologic disorders that share the histopathology of inflammation of blood vessels. Unrecognized and therefore untreated, vasculitis of the nervous system leads to pervasive injury and disability making this a disorder of paramount importance to all clinicians. Headache may be an important clue to vasculitic involvement of central nervous system (CNS) vessels. CNS vasculitis may be primary, in which only intracranial vessels are involved in the inflammatory process, or secondary to another known disorder with overlapping systemic involvement. Primary neurologic vasculitides can be diagnosed with assurance after intensive evaluation that incudes tissue confirmation whenever possible.

Evaluation of complete blood cell count parameters and lymphocyte-related ratios in patients with Opioid Use Disorder

Complete blood count (CBC) parameters and lymphocyte-related ratios are found to be associated with inflammation and increased cytokine production. In Opioid Use Disorder (OUD), CBC parameters can be examined as the inflammatory (oxidative stress) biomarkers which could be used as an objective marker to support the OUD diagnosis and could be used as a disease severity marker. CBC parameters of 142 patients with OUD were examined. Lymphocytes, monocytes, basophiles, eosinophils and platelet counts (PLT), red blood cell levels (HGB), mean erythrocyte volume (MCV) and lymphocyte-related ratios were calculated. The control group consisted of 140 healthy individuals. WBC, neutrophil, lymphocyte, monocyte, platelet count, neutrophil, basophil percentage, neutrophil/ lymphocyte ratio (NLR), monocyte/lymphocyte ratio (MLR) values were significantly higher in OUD group. Lymphocyte, basophil percentage, basophile/lymphocyte ratio (BLR), red blood cell (RBC), hemoglobin were significantly higher in control group. Mean platelet volume (MPV), eosinophil/lymphocyte ratio (ELR), platelet/ lymphocyte ratio (PLR) values were not significant yet higher in the OUD group. CBC and related parameters (WBC, neutrophil, lymphocyte, monocyte, platelet count, neutrophil, basophil percentage, NLR, MLR) were found to be significantly higher in the OUD group. Evaluation of CBC parameters could be useful in treatment and follow-up of patients with OUD.

The immunomodulatory effects of opioids and implications for intensive care unit populations

Analgesia within the intensive care unit (ICU) is often achieved via the utilization of opioids in alignment with current guidelines. Recent evidence has not only demonstrated the potential impact of opioids in suppression of immune function, but also the potential harm of immunosuppression of patients within the ICU. Despite the potential immunosuppression seen with opioids in this at-risk population, their use remains frequent. In this review, we highlight the potential immunomodulatory impact of opioids within the critically ill and considerations for their use.

Cracking the Opium Den: Cardiothoracic Manifestations of Drug Abuse

Recreational drug use is increasing worldwide, with emergency room visits and total deaths from drug overdose rising in recent years. Complications from prescription and recreational drug use may result from the biochemical effects of the drugs themselves, impurities mixed with substances, or from causes related to the method of drug administration. The presentation of drug overdose may be complex due to multisubstance abuse, including cigarette smoking and alcoholism, and can impact any organ system. Patients may present without history, and radiologists may be the first clinicians to suggest the diagnosis. We aim to explore the cardiothoracic manifestations of drug abuse and their multimodality imaging manifestations.

The molecular neurobiology and neuropathology of opioid use disorder

The number of people diagnosed with opioid use disorder has skyrocketed as a consequence of the opioid epidemic and the increased prescribing of opioid drugs for chronic pain relief. Opioid use disorder is characterized by loss of control of drug taking, continued drug use in the presence of adverse consequences, and repeated relapses to drug taking even after long periods of abstinence. Patients who suffer from opioid use disorder often present with cognitive deficits that are potentially secondary to structural brain abnormalities that vary according to the chemical composition of the abused opioid. This review details the neurobiological effects of oxycodone, morphine, heroin, methadone, and fentanyl on brain neurocircuitries by presenting the acute and chronic effects of these drugs on the human brain. In addition, we review results of neuroimaging in opioid use disorder patients and/or histological studies from brains of patients who had expired after acute intoxication following long-term use of these drugs. Moreover, we include relevant discussions of the neurobiological mechanisms involved in promoting abnormalities in the brains of opioid-exposed patients. Finally, we discuss how novel strategies could be used to provide pharmacological treatment against opioid use disorder.

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Brain abnormalities caused by opioid intoxication.

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Intoxication of opioids leads to defects in brain neurocircuitries.

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Insight into the molecular mechanisms associated with craving in heroin addicts.

Cerebral vasculitis associated with drug abuse

PURPOSE OF REVIEW

To review understand the epidemiology, background, neuropharmacology, and histopathology of literature verified cases, and likely etiopathogenic mechanisms.

RECENT FINDINGS

There are only a handful of histologically confirmed patients in the literature with cerebral vasculitis because of drug abuse.

SUMMARY

There is little justification for invasive laboratory investigation given the ready availability of highly accurate vascular neuroimaging techniques to dictate management, which usually rests upon avoidance of further exposure and minimizing the secondary neurotoxic effects of the abused substances and polypharmacy use.

Expression of a heroin contextually conditioned immune effect in male rats requires CaMKIIα-expressing neurons in dorsal, but not ventral, subiculum and hippocampal CA1

The physiological and motivational effects of heroin and other abused drugs become associated with environmental (contextual) stimuli during repeated drug use. As a result, these contextual stimuli gain the ability to elicit drug-like conditioned effects. For example, after context-heroin pairings, exposure to the heroin-paired context alone produces similar effects on peripheral immune function as heroin itself. Conditioned immune effects can significantly exacerbate the adverse health consequences of heroin use. Our laboratory has shown that exposure to a heroin-paired context suppresses lipopolysaccharide (LPS)-induced splenic nitric oxide (NO) production in male rats, and this effect is mediated in part by the dorsal hippocampus (dHpc). However, specific dHpc output regions, whose efferents might mediate conditioned immune effects, have not been identified, nor has the contribution of ventral hippocampus (vHpc) been investigated. Here, we evaluated the role of CaMKIIα-expressing neurons in the dHpc and vHpc main output regions by expressing G_i-coupled designer receptors exclusively activated by designer drugs (DREADDs) under a CaMKIIα promoter in the dorsal subiculum and CA1 (dSub, dCA1) or ventral subiculum and CA1 (vSub, vCA1). After context-heroin conditioning, clozapine-N-oxide (CNO, DREADD agonist) or vehicle was administered systemically prior to heroin-paired context (or home-cage control) exposure and LPS immune challenge. Chemogenetic inhibition of CaMKIIα-expressing neurons in dHpc, but not vHpc, output regions attenuated the expression of conditioned splenic NO suppression. These results establish that the main dHpc output regions, the dSub and dCA1, are critical for this context-heroin conditioned immune effect.

Prevalence and recurrence of bacteraemia in hospitalised people who inject drugs - a single Centre retrospective cohort study in Denmark

Background

People who inject drugs (PWID) have increased risk of acquiring blood-transmitted chronic viral infections such as Hepatitis B (HBV), Hepatitis C (HCV) and Human Immunodeficiency Virus (HIV) as well as increased risk of acquiring bacterial infections. We aimed to identify and describe bacteraemic episodes, their recurrence rates, predictive and prognostic factors amongst hospitalised PWID.

Methods

In this retrospective cohort study, we included 257 hospitalised PWID during 2000–2006 with follow up at the Department of Infectious Diseases, Hvidovre Hospital, Denmark. Data collection included comorbidity (HBV-, HCV-, HIV-, and psychiatric comorbidities), social information (contact to an addiction treatment centre, homelessness), opioid substitution treatment (OST), treatment completion and microbiology findings. There was a 10-years follow-up regarding mortality.

Results

The study identified 257 patients classified as PWID. Of these, 58 (22.6%) had at least one episode of bacteraemia during their first hospital admission. Recurrence was found in 29 (50.0%) of the bacteraemia cases. Staphylococcus aureus was the dominant microorganism of both first and recurrent episodes with 24 (41.4%) and nine (31.4%) of cases, respectively. A psychiatric diagnose was significantly associated with a lower risk of bacteraemia in the multivariate analysis (OR: 0.29, [95%CI: 0.11–0.77], P = 0.01). Mortality was significantly higher in patients with bacteraemia (17.2% vs. 3.0%, P < 0.01, OR: 6.67 [95%CI: 2.33–20], P < 0.01).

Conclusions

In hospitalised PWID, bacteraemia was found in 22.6% and was associated with at higher mortality. The most common microorganism of bacteraemia was S. aureus. Psychiatric comorbidity was significantly associated with a lower risk of bacteraemia.

The Role of Opioid Receptors in Immune System Function

Research on the effects of opioids on immune responses was stimulated in the 1980s by the intersection of use of intravenous heroin and HIV infection, to determine if opioids were enhancing HIV progression. The majority of experiments administering opioid alkaloids (morphine and heroin) in vivo, or adding these drugs to cell cultures in vitro, showed that they were immunosuppressive. Immunosuppression was reported as down-regulation: of Natural Killer cell activity; of responses of T and B cells to mitogens; of antibody formation in vivo and in vitro; of depression of phagocytic and microbicidal activity of neutrophils and macrophages; of cytokine and chemokine production by macrophages, microglia, and astrocytes; by sensitization to various infections using animal models; and by enhanced replication of HIV in vitro. The specificity of the receptor involved in the immunosuppression was shown to be the mu opioid receptor (MOR) by using pharmacological antagonists and mice genetically deficient in MOR. Beginning with a paper published in 2005, evidence was presented that morphine is immune-stimulating via binding to MD2, a molecule associated with Toll-like Receptor 4 (TLR4), the receptor for bacterial lipopolysaccharide (LPS). This concept was pursued to implicate inflammation as a mechanism for the psychoactive effects of the opioid. This review considers the validity of this hypothesis and concludes that it is hard to sustain. The experiments demonstrating immunosuppression were carried out in vivo in rodent strains with normal levels of TLR4, or involved use of cells taken from animals that were wild-type for expression of TLR4. Since engagement of TLR4 is universally accepted to result in immune activation by up-regulation of NF-κB, if morphine were binding to TLR4, it would be predicted that opioids would have been found to be pro-inflammatory, which they were not. Further, morphine is immunosuppressive in mice with a defective TLR4 receptor. Morphine and morphine withdrawal have been shown to permit leakage of Gram-negative bacteria and LPS from the intestinal lumen. LPS is the major ligand for TLR4. It is proposed that an occult variable in experiments where morphine is being proposed to activate TLR4 is actually underlying sepsis induced by the opioid.

Central Nervous System Vasculitis Due to Substance Abuse

Illicit drug abuse is a common differential diagnosis of acquired central nervous system vasculitis even though there are only a handful of histopathologically confirmed patients in the literature from among the many potential classes of abused drugs traditionally implicated in this disease. This article considers the major classes of illicit drugs in those with and without human immunodeficiency virus type-1 infection and acquired immune deficiency syndrome.

Total knee arthroplasty in patients with a history of illicit intravenous drug abuse

PURPOSE

Injection drug users are at high risk for both infection with blood-borne pathogens, namely, human immune deficiency virus (HIV), hepatitis-B, -C virus, various bacterial infections, as well as early primary and secondary joint degeneration. When total knee arthroplasty (TKA) is anticipated the risk of septic complications is a major concern. The purpose of this study was to assess the clinical and radiographic outcome of patients with a history of intravenous drug use after total knee arthroplasty. The primary outcome was revision rate. Secondary outcomes were the Western Ontario and McMaster Universities Arthritis Index (WOMAC), Knee Society Score (KSS) and radiographic loosening.

METHODS

We retrospectively reviewed the records of 1,692 TKA performed or revised in our institution. Data of 18 TKA in 12 patients (11 male, 1 female; average age 42, range 23-62 years) with a history of intravenous opioid abuse were available for final analysis.

RESULTS

The mean follow up was 125 (range 25-238) months. Seven patients required revision surgery due to periprosthetic joint infection after 62 months (range 5-159): one two staged revision, three arthrodesis and three amputations. The median prosthesis survival was 101 (95%-CI 48-154) months.

CONCLUSION

Total knee arthroplasty in patients with a history of intravenous drug abuse is associated with major complications, including above-the-knee amputation. If permanent abstinence from intravenous drug abuse is doubtful, other therapeutic options including primary arthrodesis should be considered.

Brain temperature effects of intravenous heroin: State dependency, environmental modulation, and the effects of dose

Here we examined how intravenous heroin at a dose that maintains self-administration (0.1 mg/kg) affects brain temperature homeostasis in freely moving rats under conditions that seek to mimic some aspects of human drug use. When administered under standard laboratory conditions (quiet rest at 22 °C ambient temperature), heroin induced moderate temperature increases (1.0-1.5 °C) in the nucleus accumbens (NAc), a critical structure of the brain motivation-reinforcement circuit. By simultaneously recording temperatures in the temporal muscle and skin, we demonstrate that the hyperthermic effects of heroin results primarily from inhibition of heat loss due to strong and prolonged skin vasoconstriction. Heroin-induced brain temperature increases were enhanced during behavioral activation (i.e., social interaction) and in a moderately warm environment (29 °C). By calculating the "net" effects of the drug in these two conditions, we found that this enhancement results from the summation of the hyperthermic effects of heroin with similar effects induced by either social interaction or a warmer environment. When the dose of heroin was increased (to 0.2, 0.4, 0.8, 1.6, 3.2, and 6.4 mg/kg), brain temperature showed a biphasic down-up response. The initial temperature decrease was dose-dependent and resulted from a transient inhibition of intra-brain heat production coupled with increased heat loss via skin surfaces-the effects typically induced by general anesthetics. These initial inhibitory effects induced by large-dose heroin injections could be related to profound CNS depression-the most serious health complications typical of heroin overdose in humans.

Trust and other Characteristics Associated with Health Care Utilization by Injection Drug Users

This article examines health care utilization among injection drug users. Based on previous health care models, we identify various attitudes and personal characteristics that have been found to affect health care utilization in the general population, and we examine their effect with this at-risk group. They include trust in physicians, self-esteem, self-efficacy, social isolation, and depression. We examined survey data collected from 374 injection drug users in New Haven, Connecticut. Our findings indicated that trust in physicians significantly increased health care utilization, and depression decreased it. We also found that HIV+ respondents as well as those with health insurance utilized health care more often. These findings broaden the generalizability of existing health care utilization models, and they inform efforts to increase health care among vulnerable populations such as injection drug users.

Safer Injection Facilities in North America: Their Place in Public Policy and Health Initiatives

The continuing threat posed by HIV, HCV, drug overdose, and other injection-related health problems in both the United States and Canada indicates the need for further development of innovative interventions for drug injectors, for reducing disease and mortality rates, and for enrolling injectors into drug treatment and other health care programs. Governmentally sanctioned “safer injection facilities” (SIFs) are a service that many countries around the world have added to the array of public health programs they offer injectors. In addition to needle exchange programs, street-outreach and other services, SIFs are clearly additions to much larger comprehensive public health initiatives that municipalities pursue in many countries. A survey of the existing research literature, plus the authors' ethnographic observations of 18 SIFs operating in western Europe and one SIF that was recently opened in Sydney, Australia, suggest that SIFs target several problems that needle exchange, street-outreach, and other conventional services fall short in addressing: (1) reducing rates of drug injection and related-risks in public spaces; (2) placing injectors in more direct and timely contact with medical care, drug treatment, counseling, and other social services; (3) reducing the volume of injectors' discarded litter in, and expropriation of, public spaces. In light of the evidence, the time has come for more municipalities within North America to begin considering the place of SIFs in public policy and health initiatives, and to provide support for controlled field trials and demonstration projects of SIFs operating in injection drug-using communities.

Safer Injection Sites in New York City: A Utilization Survey of Injection Drug Users

HIV, hepatitis B & C, drug overdose, and other drug-related health problems still pose significant health risks to injection drug users (IDUs) and their sexual partners, indicating the need for further development of innovative public health interventions. A relatively new intervention implemented in many municipalities throughout the world is the “safer injection site” (SIS). An SIS is a legal facility that allows people to prepare and inject pre-obtained drugs in a hygienic, anxiety-free atmosphere under the supervision of health personnel. This paper examines the responses of a sample of IDUs in New York City to whether they would use an SIS should one be implemented in mid-town Manhattan. The SIS would be part of a comprehensive harm reduction project that already offers needle-exchange, street outreach, testing and counseling, support groups, referral services including drug treatment, and on-site primary medical and dental services. The results of our study indicate that a large majority of the IDUs sampled would utilize an SIS should one be implemented, and that those most likely to use it are IDUs at the highest risk for contracting or spreading blood-borne diseases such as HIV and hepatitis, and for experiencing a drug overdose.

Acquisition of heroin conditioned immunosuppression requires IL-1 signaling in the dorsal hippocampus

Opioid users experience increased incidence of infection, which may be partially attributable to both direct opiate-immune interactions and conditioned immune responses. Previous studies have investigated the neural circuitry governing opioid conditioned immune responses, but work remains to elucidate the mechanisms mediating this effect. Our laboratory has previously shown that hippocampal IL-1 signaling, specifically, is required for the expression of heroin conditioned immunosuppression following learning. The current studies were designed to further characterize the role of hippocampal IL-1 in this phenomenon by manipulating IL-1 during learning. Experiment 1 tested whether hippocampal IL-1 is also required for the acquisition of heroin conditioned immunosuppression, while Experiment 2 tested whether hippocampal IL-1 is required for the expression of unconditioned heroin immunosuppression. We found that blocking IL-1 signaling in the dorsal hippocampus with IL-1RA during each conditioning session, but not on interspersed non-conditioning days, significantly attenuated the acquisition of heroin conditioned immunosuppression. Strikingly, we found that the same IL-1RA treatment did not alter unconditioned immunosuppression to a single dose of heroin. Thus, IL-1 signaling is not a critical component of the response to heroin but rather may play a role in the formation of the association between heroin and the context. Collectively, these studies suggest that IL-1 signaling, in addition to being involved in the expression of a heroin conditioned immune response, is also involved in the acquisition of this effect. Importantly, this effect is likely not due to blocking the response to the unconditioned stimulus since IL-1RA did not affect heroin's immunosuppressive effects.

Headaches and vasculitis

Vasculitis is a spectrum of clinicopathologic disorders defined by inflammation of arteries of veins of varying caliber with variable tissue injury. Headache may be an important clue to vasculitic involvement of central nervous system (CNS) vessels. CNS vasculitis may be primary, in which only intracranial vessels are involved in the inflammatory process, or secondary to another known disorder with overlapping systemic involvement. A suspicion of vasculitis based on the history, clinical examination, or laboratory studies warrants prompt evaluation and treatment to forestall progression and avert cerebral ischemia or infarction.

Morphine induced exacerbation of sepsis is mediated by tempering endotoxin tolerance through modulation of miR-146a

Development of tolerance to endotoxin prevents sustained hyper inflammation during systemic infections. Here we report for the first time that chronic morphine treatment tempers endotoxin tolerance resulting in persistent inflammation, septicemia and septic shock. Morphine was found to down-regulate endotoxin/LPS induced miR-146a and 155 in macrophages. However, only miR-146a over expression, but not miR-155 abrogates morphine mediated hyper-inflammation. Conversely, antagonizing miR-146a (but not miR-155) heightened the severity of morphine-mediated hyper-inflammation. These results suggest that miR-146a acts as a molecular switch controlling hyper-inflammation in clinical and/or recreational use of morphine.

Heroin-induced conditioned immunomodulation requires expression of IL-1β in the dorsal hippocampus

Opioid-associated environmental stimuli elicit robust immune-altering effects via stimulation of a neural circuitry that includes the basolateral amygdala and nucleus accumbens. These brain regions are known to have both direct and indirect connections with the hippocampus. Thus, the present study evaluated whether the dorsal hippocampus (DH), and more specifically interleukin-1 beta (IL-1β) within the DH, is necessary for the expression of heroin-induced conditioned immunomodulation. Rats received five Pavlovian pairings of systemic heroin administration (1.0mg/kg, SC) with placement into a distinct environment (conditioned stimulus, CS). Six days after conditioning, a GABAA/B agonist cocktail or IL-1β small interfering RNA (siRNA) was microinfused into the DH to inhibit neuronal activity or IL-1β gene expression prior to CS or home cage exposure. Control animals received saline or negative control siRNA microinfusions. Furthermore, all rats received systemic administration of lipopolysaccharide (LPS) to stimulate proinflammatory nitric oxide production. CS exposure suppressed LPS-induced nitric oxide production relative to home cage exposure. Inactivation of, or IL-1β silencing in, the DH disrupted the CS-induced suppression of nitric oxide production relative to vehicle or negative control siRNA treatment. These results are the first to show a role for DH IL-1β expression in heroin-conditioned suppression of a proinflammatory immune response.

Cross-sectional study of the characteristics, healthcare usage, morbidity and mortality of injecting drug users attending an inner city emergency department

BACKGROUND

The affliction of injecting drug use (IDU) has resulted in the emergence of a subgroup of people with a unique set of medical issues. We aimed to describe the emergency department (ED) presentations of IDUs.

METHODS

In a prospective observational study over a 3-month period, we identified characteristics of patients with a history of active IDU presenting to the ED.

RESULTS

From 1 January 2010 to 31 March 2010, 146 patients with a history of IDU were identified. These contributed to 222 acute presentations to the ED. Baseline characteristics revealed that patients were predominantly male, of Irish nationality, with high levels of homelessness, unemployment and lack of stable family or intimate partner relationships. 45% of presentations occurred as a result of infection (95% CI 38.5% to 51.5%). Trauma, pure toxicological issues, thromboembolic phenomena and psychiatric issues comprised the other common acute diagnoses. The burden of comorbid medical illness was substantial with high rates of hepatitis C infection (74%) and HIV infection (13.8%). Healthcare utilisation indices for this cohort are extreme on multiple measures. We found an ED attendance rate of 445 per 100 patient-years, an admission rate of 68.8 per 100 patient-years and mortality rate of 4.86 per 100 patient-years.

CONCLUSIONS

Our study characterises the emergency presentations of active IDUs. We describe considerable acute and chronic medical consequences and high healthcare utilisation associated with IDU. This study is of particular relevance to any institution that provides acute medical care to this group of patients.

Role of the mu-opioid receptor in opioid modulation of immune function

Endogenous opioids are synthesized in vivo to modulate pain mechanisms and inflammatory pathways. Endogenous and exogenous opioids mediate analgesia in response to painful stimuli by binding to opioid receptors on neuronal cells. However, wide distribution of opioid receptors on tissues and organ systems outside the CNS, such as the cells of the immune system, indicate that opioids are capable of exerting additional effects in the periphery, such as immunomodulation. The increased prevalence of infections in opioid abuser-based epidemiological studies further highlights the immunosuppressive effects of opioids. In spite of their many debilitating side effects, prescription opioids remain a gold standard for treatment of chronic pain. Therefore, given the prevalence of opioid use and abuse, opioid-mediated immune suppression presents a serious concern in our society today. It is imperative to understand the mechanisms by which exogenous opioids modulate immune processes. In this review, we will discuss the role of opioid receptors and their ligands in mediating immune-suppressive functions. We will summarize recent studies on direct and indirect opioid modulation of the cells of the immune system, as well as the role of opioids in exacerbation of certain disease states.

Morphine, but not trauma, sensitizes to systemic Acinetobacter baumannii infection

Acinetobacter baumannii is an important nosocomial pathogen in civilian intensive care units. Recently the incidence has increased in wounded military personnel. Morphine is documented in numerous animal studies to be immunosuppressive and to sensitize to infection. The hypotheses were tested that morphine, administered for analgesia in the battlefield, predisposes to Acinetobacter infection, and that the opioid may have an additive or synergistic effect with trauma. To test these hypotheses, an intraperitoneal infection model was established in mice using several Acinetobacter strains. Morphine administered for 48 h by implantation of a slow-release morphine pellet increased mortality compared to animals receiving a placebo pellet, an effect that was blocked by the mu-opioid receptor antagonist, naltrexone. Acinetobacter burdens in the blood, spleens, livers, and lungs of morphine-treated mice, were significantly higher than those in placebo-treated animals, confirming that mortality was due to potentiated growth of the bacteria. There were also elevated levels of pro-inflammatory cytokines in morphine-treated versus placebo-treated mice. Morphine caused a reduction in the total number of cells in the peritoneal cavity, a decrease in the percentage and total numbers of neutrophils, and a decrease in the total number of macrophages. Morphine treatment also suppressed levels of the neutrophil-inducing molecules, IL-17A and KC/CXCL1. However, IL-17A(-/-) mice given morphine were not sensitized to Acintobacter infection to a greater degree than similarly treated wild-type mice. Trauma alone did not sensitize to Acinetobacter infection, and there was no additive effect between morphine and trauma. These results support the hypothesis that morphine potentiates Acinetobacter infection.

Correlates of risky injection practices among past-year injection drug users among the US general population

BACKGROUND

With an estimated 1 million active injection drug users (IDUs), injection drug use continues to be a public health concern in the United States. Risky injection practices have been associated with the transmission of HIV, Hepatitis B and C, as well as other skin and soft tissue infections.

METHODS

We used data from 463 respondents, aged 18 and older, who were past-year IDUs in the 2005-2008 National Survey of Drug Use and Health (NSDUH). We investigated correlates of risky injection behavior among these recent IDUs.

RESULTS

Older age (≥ 35 versus 18-25) was associated with reusing one's own needle at last injection (aOR=1.80 [1.02-3.17], as were past year heroin (aOR=2.59 [1.18-5.66]) and cocaine injection (aOR=2.17 [1.13-4.15]). Past year crack cocaine use was positively associated with not cleaning needles with bleach (aOR=2.18 [1.10-4.33]). Past year cocaine injection was associated with obtaining needles in a risky manner (aOR=2.29 [1.23-4.25]). Methamphetamine injection was associated with obtaining needles in less risky ways (aOR=0.41 [0.20-0.84]).

CONCLUSION

Our findings indicate that some IDUs are continuing to engage in high risk injection behaviors. The identification of potential at-risk populations of IDUs may have implications for harm reduction interventions and HIV prevention programs.

Assessment of the Chinese-version SF-36 in the Chinese opiate addicts

This study was designed to assess the reliability and validity of the Chinese version of the Medical Outcomes Study Short Form 36 (SF-36) assessed with opiate addicts in China. The sample was composed of 442 questionnaires from three regions in China, in 2004. The reliability of Chinese-version SF-36 was obtained using Cronbach's α and split-half coefficients and the validity was calculated using correlation analysis and confirmatory factor analysis method. The results of reliability and validity provide the first evidence that Chinese-version SF-36 is validated for Chinese addicts. The study's limitations are noted.

Dopamine D1 receptors within the basolateral amygdala mediate heroin-induced conditioned immunomodulation

This study investigates the role of basolateral amygdala (BLA) dopamine in heroin-induced conditioned immunomodulation. Animals underwent conditioning in which heroin administration was repeatedly paired with placement into a conditioning chamber. Six days after the final conditioning session animals were returned to the chamber and received intra-BLA microinfusions of dopamine, D(1) or D(2), antagonist. Antagonism of D(1), but not D(2), receptors within the BLA blocked the suppressive effect of heroin-associated environmental stimuli on iNOS, TNF-α and IL-1β. This study is the first to demonstrate that the expression of heroin's conditioned effects on proinflammatory mediators require dopamine D(1) receptors within the BLA.

Neuronal adaptations, neuroendocrine and immune correlates of heroin self-administration

Opioid receptor-mediated action in the central nervous system (CNS) has been consistently shown to trigger changes in the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic nervous system (SNS) and suppress a variety of parameters of immune function in investigator-delivered paradigms. Overwhelming evidence supports the concept that the CNS undergoes numerous and complex neuronal adaptive changes in addicts, and in animal models of heroin addiction as a result of the training of drug stimuli to serve as reinforcers, altering the function of individual neurons and the larger neural circuits within which the neurons operate. Taken together, these advances suggest that since plastic neuronal changes occur in drug addiction and related animal model paradigms, profiles of neuroendocrine and immune function would differ in a rat model of heroin self-administration compared to passive infusion of drug. Self-administration of heroin induces neuronal circuitry adaptations in specific brain regions that may be related to alterations in neuroendocrine and T lymphocyte function also observed. Animals self-administering (SA) heroin exhibit increased mu-opioid receptor agonist ([D-Ala2, N-Me-Phe4, Gly5-ol]-enkephalin (DAMGO))-stimulated guanosine-5'-O-(gamma-thio)-triphosphate ([(35)S]GTPgammaS) binding in the anterior hypothalamus (50% and 33%) and rostral medial thalamus (33% and 36%) compared with control animals receiving identical non-contingent injections of yoked-heroin (YH) or yoked-saline (YS), respectively. No changes in agonist-stimulated G-protein sensitization were observed in 14 other brain regions studied. No changes in mu-opioid receptor density, ((3)H-DAMGO binding) were seen in all brain regions examined. The neuronal changes in SA animals were correlated with elevated adrenocorticotrophic hormone (ACTH) (64% and 104%) and glucocorticoid production (198% and 79%) compared with YH and YS groups, respectively. Neuroendocrine adaptive changes in SA animals were associated with thymic hypoplasia. Splenic T lymphocytes from animals that had self-administered heroin showed a profoundly reduced ability to proliferate in response to concanavalin A (50% and 48% compared with YH and YS controls, respectively; Fig. 1A), or a monoclonal antibody (R73) to the CD3/T-cell receptor complex (anti-TCR) plus IL-2 (55% and 59% compared with YH and YS controls, respectively; Fig. 1B). Self-administration of heroin selectively alters T lymphocyte function, as no effects on natural killer cell activity or macrophage functions were observed. These findings may have relevance to the acquisition and documented increased incidence of infectious diseases, including HIV, in heroin addicts, due to a pre-existing T-cell immunodeficient state.

Evidence for the nucleus accumbens as a neural substrate of heroin-induced immune alterations

Administration of opioid drugs such as heroin produces several immunosuppressive effects, including decreases in natural killer (NK) cell activity, lymphocyte proliferative responses, and nitric oxide production. Interestingly, opioids have been shown to alter many immune parameters indirectly by modulating the immunoregulatory actions of the central nervous system. Recently, it has been demonstrated that morphine inhibits NK cell activity through a neural pathway that requires the activation of dopamine D(1) receptors in the nucleus accumbens shell. The present study examined whether the nucleus accumbens also mediates the effects of heroin, a more commonly abused opioid, on several parameters of immune status in Lewis rats. The results showed that bilateral administration of the dopamine D(1) receptor antagonist R-(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochloride (SCH-23390; 0.015 and 0.15 microg/side) into the nucleus accumbens shell blocked decreases in splenic NK activity produced by heroin (3 mg/kg s.c.) but did not attenuate the suppression of splenocyte proliferative responses to concanavalin-A or lipopolysaccharide (LPS). A subsequent experiment was performed to evaluate the effect of D(1) receptor antagonism on LPS-induced expression of inducible nitric-oxide synthase (iNOS) in vivo. These results showed that intra-accumbens SCH-23390 administration prevented heroin-induced reductions of iNOS mRNA expression in spleen, liver, and lung tissues and attenuated the suppression of nitric oxide levels in plasma. Collectively, these findings indicate that nucleus accumbens dopamine D(1) receptors are critically involved in heroin-induced immune alterations.

Crack-cocaine use accelerates HIV disease progression in a cohort of HIV-positive drug users

BACKGROUND

HIV infection is prevalent among substance abusers. The effects of specific illicit drugs on HIV disease progression have not been established. We evaluated the relationship between substances of abuse and HIV disease progression in a cohort of HIV-1-positive active drug users.

METHODS

A prospective, 30-month, longitudinal study was conducted on 222 HIV-1 seropositive drug users in Miami, FL. History of illicit drug, alcohol, and medication use, CD4+ cell count, and viral load were performed every 6 months.

RESULTS

Crack-cocaine users were 2.14 times [95% confidence interval (CI): 1.08 to 4.25, P = 0.029] more likely to present a decline of CD4 to <or=200 cells/mL, independent of antiretroviral use. Viral load over 30 months was significantly higher in crack users (beta = 0.315, P = 0.037) independent of highly active antiretroviral therapy (HAART) over time. The only multidrug combination that significantly increased the risk of disease progression was crack cocaine with marijuana (hazard ratio = 2.42; 95% CI: 1.042 to 5.617, P = 0.04). Of those on HAART, a significantly lower proportion of crack-cocaine users versus nonusers had controlled viral load (P < 0.001), suggesting lower medication adherence, whereas crack-cocaine users not on HAART showed a greater risk for HIV disease progression than nonusers (hazard ratio = 3.946; 95% CI: 1.049 to 14.85, P = 0.042).

CONCLUSIONS

Crack-cocaine use facilitates HIV disease progression by reducing adherence in those on HAART and by accelerating disease progression independently of HAART.

Can one predict outcome of medical coma?

The combined evaluation of the motor response to stimulation and the oculovestibular (OV) reflex gives useful indicants to the outcome of medical coma. We examined 48 patients during the first 12 h and at 24 h after the onset of medical coma. We excluded patients who had ingested drugs or who had hypothermia. Motor responses to a noxious stimulus were scored on a 6 'best' and 1 'worst' scale, and the presence or absence of oculovestibular responses to icewater irrigations was recorded. Subjects were divided by outcome at three months into three groups: death or persistent vegetative state, severe disability, and moderate disability or good recovery. On the basis of the present series it was often possible to distinguish among the outcomes at or before 24 h. The patient's age and the presence or absence of pupillary responses, spontaneous eye movements and oculocephalic responses were not predictive of outcome, nor were the respiratory pattern, blood gases, blood pressure, heart rate and temperature. A minimal motor score and an absence of oculovestibular responses at 12 h always were assoicated with death. With higher motor scores, the absence of oculovestibular responses at either 12 or 24 h implied an outcome no better than severe disability. The results of the present study imply that early bedside assessments can yield accurate predictive information in medical coma.

Appropriateness of antibiotic treatment in intravenous drug users, a retrospective analysis

Background

Infectious disease is often the reason for intravenous drug users being seen in a clinical setting. The objective of this study was to evaluate the appropriateness of treatment and outcomes for this patient population in a hospital setting.

Methods

Retrospective study of all intravenous drug users hospitalized for treatment of infectious diseases and seen by infectious diseases specialists 1/2001–12/2006 at a university hospital. Treatment was administered according to guidelines when possible or to alternative treatment program in case of patients for whom adherence to standard protocols was not possible. Outcomes were defined with respect to appropriateness of treatment, hospital readmission, relapse and mortality rates. For statistical analysis adjustment for multiple hospitalizations of individual patients was made by using a generalized estimating equation.

Results

The total number of hospitalizations for infectious diseases was 344 among 216 intravenous drug users. Skin and soft tissue infections (n = 129, 37.5% of hospitalizations), pneumonia (n = 75, 21.8%) and endocarditis (n = 54, 15.7%) were most prevalent. Multiple infections were present in 25%. Treatment was according to standard guidelines for 78.5%, according to an alternative recommended program for 11.3%, and not according to guidelines or by the infectious diseases specialist advice for 10.2% of hospitalizations. Psychiatric disorders had a significant negative impact on compliance (compliance problems in 19.8% of hospitalizations) in multiple logistic regression analysis (OR = 2.4, CI 1.1–5.1, p = 0.03). The overall readmission rate and relapse rate within 30 days was 13.7% and 3.8%, respectively. Both non-compliant patient behavior (OR = 3.7, CI 1.3–10.8, p = 0.02) and non-adherence to treatment guidelines (OR = 3.3, CI 1.1–9.7, p = 0.03) were associated with a significant increase in the relapse rate in univariate analysis. In 590 person-years of follow-up, 24.6% of the patients died: 6.4% died during hospitalization (1.2% infection-related) and 13.6% of patients died after discharge.

Conclusion

Appropriate antibiotic therapy according to standard guidelines in hospitalized intravenous drug users is generally practicable and successful. In a minority alternative treatments may be indicated, although associated with a higher risk of relapse.

Radiology of Recreational Drug Abuse

Recreational drug abuse is increasing throughout the world. Use of these drugs may result in a diverse array of acute and chronic complications involving almost any body organ, and imaging frequently plays a vital role in detection and characterization of such complications. The nature of the complications depends to a large extent on the drug used, the method of administration, and the impurities associated with the drug. Radiologically demonstrable sequelae may be seen after use of opiates, cocaine, amphetamines and their derivatives such as 3,4-methylenedioxymethamphetamine ("ecstasy"), marijuana, and inhaled volatile agents including amyl nitrite ("poppers") and industrial solvents such as toluene. Cardiovascular complications include myocardial infarction, cardiomyopathy, arterial dissection, false and mycotic aneurysms, venous thromboembolic disease, and septic thrombophlebitis. Respiratory complications may involve the upper airways, lung parenchyma, pulmonary vasculature, and pleural space. Neurologic complications are most commonly due to the cerebrovascular effects of illicit drugs. Musculoskeletal complications are dominated by soft-tissue, bone, and joint infections caused by intravenous drug use. Awareness of the imaging features of recreational drug abuse is important for the radiologist because the underlying cause may not be known at presentation and because complications affecting different body systems may coexist. Intravenous drug abuse in particular should be regarded as a multisystem disease with vascular and infective complications affecting many parts of the body, often synchronously. Discovery of one complication should prompt the radiologist to search for coexisting pathologic conditions, which may alter management.

Conditioned effects of heroin on the expression of inducible nitric oxide synthase in the rat are susceptible to extinction and latent inhibition

RATIONALE

The administration of heroin has been shown to inhibit the induction of nitric oxide, a molecule known to play a critical role in immune function. Previous research has shown that this alteration can be conditioned to environmental stimuli that have been associated with drug administration. However, it remains unknown whether the conditioned effects of heroin on nitric oxide formation follow accepted principles of learning.

OBJECTIVE

This study sought to determine whether manipulations that induce extinction and latent inhibition, two learning paradigms known to reduce the expression of conditioned responses, would alter heroin's conditioned effects on the expression of inducible nitric oxide synthase (iNOS).

MATERIALS AND METHODS

The conditioning procedure involved repeated pairing of heroin administration with placement into a standard conditioning chamber. Rats were repeatedly exposed to the chambers without heroin reinforcement to determine whether the conditioned response would extinguish. To induce latent inhibition, rats received repeated exposure to the chamber before the start of conditioning to inhibit the acquisition of the conditioned response. Ten days after the final conditioning session, all rats were injected with lipopolysaccharide (LPS) to induce iNOS expression. Spleen and liver tissue were removed to determine iNOS expression using reverse transcriptase polymerase chain reaction. Blood was collected to determine the concentration of nitrite/nitrate.

RESULTS

The results showed that both extinction and latent inhibition reduced the conditioned effects of heroin on the production of nitric oxide.

CONCLUSION

This study provides the first evidence that the conditioned effects of heroin on nitric oxide production follow accepted principles of learning.

Observed patterns of illicit opiate overdose deaths in Chicago, 1999-2003

This article explores trends and correlates of Chicago's opiate-related overdose (OD) deaths. We manually examined data from every death certificate filed between 1999 and 2003 to identify all Chicago residents' accidental deaths involving acute intoxication with illicit opiates, OD, or opiate poisoning. The analysis includes an examination of contextual characteristics in 77 Chicago neighborhoods. Negative binomial regression analysis permits the calculation of incidence rate ratios (IRR) associated with time trends. OD incidence peaked in 2000 and then declined markedly by 2003 [year 2000-2003 IRR = 0.65, 95% confidence interval (CI) (0.54, 0.78)]. Over the 2000-2003 period, overall incidence of fatal OD declined by 34%. Over this period, the sharpest observed declines occurred among African-Americans [IRR = 0.64, 95% CI (0.51, 0.81)] and Hispanics/Latinos [IRR = 0.53, 95% CI (0.32, 0.88)]. The opiate-related fatality incidence also declined among non-Hispanic whites [IRR = 0.743, 95% CI (0.52, 1.06)]. Even at the end of the study period, illicit opiate-related OD accounted for 35% of all accidental deaths to Chicago adults aged 18-64, with 45% of OD deaths occurring among African-American men. In summary, illicit opiate OD in Chicago peaked in 2000 and markedly declined by 2003. Opiate OD continues to pose a major threat of mortality to Chicago adults.

Morphine withdrawal lowers host defense to enteric bacteria: spontaneous sepsis and increased sensitivity to oral Salmonella enterica serovar Typhimurium infection

Understanding the consequences of drug withdrawal on immune function and host defense to infection is important. We, and others, previously demonstrated that morphine withdrawal results in immunosuppression and sensitizes to lipopolysaccharide-induced septic shock. In the present study, the effect of morphine withdrawal on spontaneous sepsis and on oral infection with Salmonella enterica serovar Typhimurium was examined. Mice were chronically exposed to morphine for 96 h by implantation of a slow-release morphine pellet. Abrupt withdrawal was induced by removal of the pellet. In the sepsis model, bacterial colonization was examined and bacterial species were identified by necropsy of various tissues. It was found that at 48 h postwithdrawal, morphine-treated mice had enteric bacteria that were detected in the Peyer's patches (4/5), mesenteric lymph nodes (4/5), spleens (4/10), livers (6/10), and peritoneal cavities (8/10). In placebo pellet-withdrawn mice, only 2/40 cultures were positive. The most frequently detected organisms in tissues of morphine-withdrawn mice were Enterococcus faecium followed by Klebsiella pneumoniae. Both organisms are part of the normal gastrointestinal flora. In the infection model, mice were orally inoculated with S. enterica 24 h post-initiation of abrupt withdrawal from morphine. Withdrawal significantly decreased the mean survival time and significantly increased the Salmonella burden in various tissues of infected mice compared to placebo-withdrawn animals. Elevated levels of the proinflammatory cytokines were observed in spleens of morphine-withdrawn mice, compared to placebo-withdrawn mice. These findings demonstrate that morphine withdrawal sensitizes to oral infection with a bacterial pathogen and predisposes mice to bacterial sepsis.

Neuropeptide Y Y1 receptors mediate morphine-induced reductions of natural killer cell activity

Morphine suppresses a number of immune parameters, such as natural killer (NK) cell activity and lymphocyte proliferation, by acting through mu-opioid receptors in the central nervous system. Prior studies have implicated the sympathetic nervous system in mediating the immunomodulatory effects of acute morphine treatment. However, the peripheral mechanism whereby morphine inhibits NK cell activity is not fully understood. The aim of the present study was to investigate the role of the sympathetic transmitter neuropeptide Y (NPY) in mediating morphine-induced immune alterations. The results showed that administration of the selective NPY Y1 receptor antagonist BIBP3226 blocked morphine's effect on splenic NK activity but did not attenuate the suppression splenocyte proliferative responses to Con-A or LPS. Furthermore, intravenous NPY administration produced a dose-dependent inhibition of splenic NK activity but did not suppress lymphocyte proliferation. Recent studies from our laboratory have demonstrated that morphine modulates NK activity through a central mechanism that requires the activation of dopamine D1 receptors in the nucleus accumbens. Results from the present study showed that microinjection of the D1 receptor agonist SKF-38393 into the nucleus accumbens shell induced a suppression of NK activity that was reversed by BIBP3226. Collectively, these findings demonstrate that NPY Y1 receptors mediate morphine's suppressive effect on NK activity and further suggest that opioid-induced increases in nucleus accumbens D1 receptor activation inhibit splenic NK activity via NPY released from the sympathetic nervous system.

Comparisons of community-associated methicillin-resistant Staphylococcus aureus (MRSA) and hospital-associated MSRA infections in Sacramento, California

Methicillin-resistant Staphylococcus aureus (MRSA) has long been a common pathogen in healthcare facilities, but in the past decade, it has emerged as a problematic pathogen in the community setting as well. A retrospective case series study of patients from whom MRSA was isolated from December 1, 2003, through May 31, 2004, was conducted at the University of California, Davis, Medical Center. Patient data were collected from electronic medical records and traditional chart reviews to determine whether MRSA acquisition was likely to have been in the community or in the hospital. Antimicrobial susceptibility testing and pulsed-field gel electrophoresis (PFGE) were performed for all confirmed isolates. Skin and soft tissue were the most common infection sites for all MRSA patients. Among the 283 MRSA infections, 127 (44.9%) were defined as community-associated (CA)-MRSA. Ninety-six percent of the CA-MRSA isolates were susceptible to clindamycin. Double-disk diffusion tests were performed to examine inducible clindamycin resistance by erythromycin induction on both CA and hospital-associated (HA) clindamycin-susceptible and erythromycin-resistant isolates. Ten percent (17 of 183) were positive. Most CA-MRSA isolates were identified by PFGE as a unique strain, genotype USA300, which was not genetically related to the predominant genotype, USA100, in the HA-MRSA isolates. Injecting drug users accounted for 49% of CA-MRSA infections but only 19% of the HA-MRSA infections (odds ratio, 4.2; 95% confidence interval, 2.4 to 7.4). Our study shows that a single clone of CA-MRSA accounts for the majority of infections. This strain originated in the community and is not related to MRSA strains from healthcare settings. Injecting drug users could be a major reservoir for CA-MRSA transmission.

Medical examinations at entry to treatment for drug abuse as an opportunity to initiate care for hepatitis C virus infection

Over the course of addiction, a substantial proportion of drug users enter drug abuse treatment programs. Data from a cross-sectional survey of drug abuse treatment programs in the United States were analyzed to describe the scope of the medical examination performed at admission to such programs. All of the methadone programs (n=95) and 50% of drug-free programs (80 of 161) required a medical examination at entry. Most examinations included screening for signs and symptoms of liver disease and liver function testing. Nearly all methadone programs (97%) provided referral to medical care or support for patients with test results positive for antibody to hepatitis C virus (HCV), compared with 75% of drug-free programs (P<.01). Drug-free programs requiring medical examinations provided education about HCV and testing for HCV to a larger proportion of their patients (P<.05). With high dropout rates in the early stages of treatment for drug addiction, these medical visits may be an important opportunity for further monitoring and care for HCV infection and other conditions.

Syndrome des « grosses mains » des toxicomanes : intérêt des bandages peu élastiques

BACKGROUND

Puffy hand syndrome is a complication of intravenous drug abuse, which has no current available treatment. Arm and forearm edema are voluminous and cause functional and aesthetic disturbances. We report two cases successfully treated by low-stretch bandages.

OBSERVATIONS

A 40-year-old man and a 34-year-old woman, both intravenous drug users, with puffy hand syndrome were hospitalized for 11 days. Treatment included daily multilayer bandaging. Lymphedema volumes calculated by utilizing the formula for a truncated cone decreased by 16% on the left side and 12% on the right side for the first patient and 31 and 17% for the second. Hand circumference decreased 4.3 cm on the left side and 3.2 cm on the right side in case 1, and 2.5 cm and 1.9 cm respectively for case 2. The patients were taught self-bandaging techniques during their hospital stays. Elastic gloves were fitted at the end of treatment. Reduction of lymphedema volume remained stable after 18 months in one patient while for the second patient further treatment and hospitalization were required due to poor compliance.

DISCUSSION

The pathogenesis of this edema is probably multifactorial: venous, lymphatic insufficiency and the direct toxicity of injected drugs. Lymphedema treatment currently consists of low-stretch bandaging and wearing elastic garments, which is effective in decreasing the volume of puffy hand syndrome.

Effects of mu, kappa or delta opioids administered by pellet or pump on oral Salmonella infection and gastrointestinal transit

Our laboratory has shown previously that subcutaneously implanted, slow-release morphine pellets markedly enhanced susceptibility to oral infection with Salmonella typhimurium. Further, morphine, kappa and delta opioid receptor agonists infused via osmotic minipumps were immunosuppressive. The present study compared morphine pellets to morphine pumps and also examined the differential effects of morphine versus U50,488H (kappa agonist), deltorphin II (delta2 agonist), and (D-Pen2, D-Pen5)-enkephalin (DPDPE, delta1 agonist), administered via Alzet minipumps, on oral Salmonella infection and on gastrointestinal transit. The results show that all morphine-pelleted mice (26/26) had a marked increase in Salmonella burden in the Peyer's Patches, mesenteric lymph nodes and spleen. In comparison, only 8/20 mice receiving morphine by minipump at doses ranging from 1 to 25 mg/kg/day had any culturable Salmonella in their organs and the number of bacteria was very low. The level of Salmonella colonization correlated with blood morphine levels and gut transit measured using an intragastric charcoal meal. Morphine pellets inhibited gut transit by 38%, while mice receiving morphine by minipump at doses of 1 to 25 mg/kg/day showed only a dose-dependent 7% to 17% inhibition. Mice receiving various doses of U50,488H or DPDPE had no culturable Salmonella in the three sites. Deltorphin II given by minipump resulted in a moderate level of Salmonella in the spleen. Deltorphin II and U50,488H (0.1 to 10 mg/kg/day) did not suppress gut transit. The present studies indicate that a predominantly mu opioid receptor agonist, morphine, given by slow-release pellet, potentiated Salmonella infection and inhibited gastrointestinal transit. In contrast, morphine in pumps slightly inhibited intestinal transit, but did not sensitize to Salmonella infection. A delta1 opioid receptor agonist did not sensitize to infection, and a delta2 and a kappa opioid receptor agonist had minimal effects on either parameter.

Heroin-associated nephropathy

Since the first reports in the late 1960s and early 1970s there have been numerous studies describing the clinical and pathological features of renal diseases associated with chronic parenteral abuse of heroin, cocaine, morphine, amphetamine, and other narcotic and hallucinogenic drugs, including several adulterants. The past 35 years have witnessed an explosive growth in illicit drug use in many parts of the world. Meanwhile, drug addict nephropathy constitutes an important cause of end-stage renal disease. The term heroin-associated nephropathy' includes different morphological findings following chronic drug abuse. Up to now it still remains ambiguous as to whether or not heroin/morphine itself, adulterants, other diseases like hepatitis B and C infection, or HIV, lead to a spectrum of morphologically described heroin-associated' findings in the kidneys. As a measure of prevention it appears that the purity of heroin plays an important role.

Morphine withdrawal enhances hepatitis C virus replicon expression

We previously demonstrated that morphine enhances hepatitis C virus (HCV) replication in human hepatic cells. Here we describe the impact of morphine withdrawal (MW), a recurrent event during the course of opioid abuse, on HCV replicon expression in human hepatic cells. MW enhanced both viral RNA and protein expression in HCV replicon cells. Blocking opioid receptors by treatment with naloxone after morphine cessation (precipitated withdrawal, PW) induced greater HCV replicon expression than MW. Investigation of the mechanism responsible for MW- or PW-mediated HCV enhancement showed that both MW and PW inhibited the expression of endogenous interferon-alpha (IFN-alpha) in the hepatic cells. This down-regulation of intracellular IFN-alpha expression was due to the negative impact of MW or PW on IFN-alpha promoter activation and on the expression of IFN regulatory factor 7 (IRF-7), a strong transactivator of the IFN-alpha promoter. In addition, both MW and PW inhibited the anti-HCV ability of recombinant IFN-alpha in the hepatic cells. These in vitro observations support the concept that opioid abuse favors HCV persistence in hepatic cells by suppressing IFN-alpha-mediated intracellular innate immunity and contributes to the development of chronic HCV infection.

Increased sensitivity to Salmonella enterica serovar Typhimurium infection in mice undergoing withdrawal from morphine is associated with suppression of interleukin-12

We have shown previously that withdrawal from morphine induces immunosuppression in mice. The present study reports the effects of morphine withdrawal on infection with Salmonella enterica serovar Typhimurium. Mice were made dependent on morphine by the implantation of a slow-release morphine pellet for 96 h. Controls received a placebo pellet. Withdrawal was induced by pellet removal. Mice were inoculated intraperitoneally with Salmonella 24 h postwithdrawal. Morphine withdrawal sensitized mice to Salmonella infection, as evidenced by increased mortality, shortened mean survival time, and increased bacterial load in the blood, spleen, and liver. Examination of the levels of a panel of proinflammatory cytokines in sera of infected, morphine-withdrawn mice showed that morphine withdrawal inhibited the elevation of interleukin-12p70 (IL-12p70). The production of IL-12p40 in morphine withdrawal mice was also suppressed. The administration of exogenous IL-12 significantly decreased the bacterial burden in morphine-withdrawn mice. These studies show a correlation between the suppression of IL-12 production and a heightened susceptibility to Salmonella infection in mice undergoing withdrawal from morphine.