Mechanisms of mu opioid receptor/G-protein desensitization in brain by chronic heroin administration

Previous studies have shown that chronic opiate treatment decreases mu opioid-stimulated [35S]GTPgammaS binding in specific brain regions. To extend these findings, the present study investigated DAMGO-stimulated [35S]GTPgammaS binding in membrane homogenates and coronal sections from rats non-contingently administered heroin. Rats were administered saline or increasing doses of heroin i.v. hourly up to 288 mg/kg/day over 40 days. In brain sections, chronic heroin administration decreased DAMGO-stimulated [35S]GTPgammaS binding in medial thalamus and amygdala, with no effect in cingulate cortex or nucleus accumbens. Chronic heroin administration also reduced [35S]GTPgammaS binding stimulated by the principal metabolite of heroin, 6-monoacetylmorphine. In contrast, no significant changes in mu opioid receptor binding were observed in amygdala or thalamus using [3H]DAMGO autoradiography. In membranes from amygdala and thalamus, chronic heroin treatment decreased the maximal effect of DAMGO in stimulating [35S]GTPgammaS binding, with no effect on DAMGO potency. GTPgammaS saturation analysis showed that chronic heroin treatment decreased the Bmax, and increased the K(D), of DAMGO-stimulated [35S]GTPgammaS binding. These data suggest potential mechanisms by which chronic agonist treatment produces opioid receptor/G-protein desensitization in brain.     

Sulfonate-isosteric replacement examined within heroin-hapten vaccine design

Heroin overdose and addiction remain significant health and economic burdens in the world today costing billions of dollars annually. Moreover, only limited pharmacotherapeutic options are available for treatment of heroin addiction. In our efforts to combat the public health threat posed by heroin addiction, we have developed vaccines against heroin. To expand upon our existing heroin-vaccine arsenal, we synthesized new aryl and alkyl sulfonate ester haptens; namely aryl-mono-sulfonate (H_MsAc) and Aryl/alkyl-di-sulfonate (H_(Ds)2) as carboxyl-isosteres of heroin then compared them to our model heroin-hapten (H_Ac) through vaccination studies. Heroin haptens were conjugated to the carrier protein CRM₁₉₇ and the resulting CRM-immunoconjugates were used to vaccinate Swiss Webster mice following an established immunization protocol. Binding studies revealed that the highest affinity anti-heroin antibodies were generated by the H_MsAc vaccine followed by the H_Ac and H_(Ds)2 vaccines, respectively (H_MsAc > H_Ac≫H_Ds2). However, neither the H_MsAc nor H_(Ds)2 vaccines were able to generate high affinity antibodies to the psychoactive metabolite 6-acetyl morphine (6-AM), in comparison to the H_Ac vaccine. Blood brain bio-distribution studies supported these binding results with vaccine efficiency following the trend H_Ac > H_MsAc ≫ H_(Ds)2 The work described herein provides insight into the use of hapten-isosteric replacement in vaccine drug design.     

A Procedure to Study the Effect of Prolonged Food Restriction on Heroin Seeking in Abstinent Rats

In human drug addicts, exposure to drug-associated cues or environments that were previously associated with drug taking can trigger relapse during abstinence. Moreover, various environmental challenges can exacerbate this effect, as well as increase ongoing drug intake.The procedure we describe here highlights the impact of a common environmental challenge, food restriction, on drug craving that is expressed as an augmentation of drug seeking in abstinent rats.Rats are implanted with chronic intravenous i.v. catheters, and then trained to press a lever fori.v. heroin over a period of 10-12 days. Following the heroin self-administration phase the rats are removed from the operant conditioning chambers and housed in the animal care facility for a period of at least 14 days. While one group is maintained under unrestricted access to food (sated group), a second group (FDR group) is exposed to a mild food restriction regimen that results in their body weights maintained at 90% of their nonrestricted body weight. On day 14 of food restriction the rats are transferred back to the drug-training environment, and a drug-seeking test is run under extinction conditions (i.e. lever presses do not result in heroin delivery).The procedure presented here results in a highly robust augmentation of heroin seeking on test day in the food restricted rats. In addition, compared to the acute food deprivation manipulations we have used before, the current procedure is a more clinically relevant model for the impact of caloric restriction on drug seeking. Moreover, it might be closer to the human condition as the rats are not required to go through an extinction-training phase before the drug-seeking test, which is an integral component of the popular reinstatement procedure.     

Heat shock proteins: A dual carrier-adjuvant for an anti-drug vaccine against heroin

Heroin is a highly abused opioid that has reached epidemic status within the United States. Yet, existing therapies to treat addiction are inadequate and frequently result into rates of high recidivism. Vaccination against heroin offers a promising alternative therapeutic option but requires further development to enhance the vaccine’s performance. Hsp70 is a conserved protein with known immunomodulatory properties and is considered an excellent immunodominant antigen. Within an antidrug vaccine context, we envisioned Hsp70 as a potential dual carrier-adjuvant, wherein immunogenicity would be increased by co-localization of adjuvant and antigenic drug hapten. Recombinant Mycobacterium tuberculosis Hsp70 was appended with heroin haptens and the resulting immunoconjugate granted anti-heroin antibody production and blunted heroin-induced antinociception. Moreover, Hsp70 as a carrier protein surpassed our benchmark Her-KLH cocktail through antibody-mediated blockade of 6-acetylmorphine, the main mediator of heroin’s psychoactivity. The work presents a new avenue for exploration in the use of hapten-Hsp70 conjugates to elicit anti-drug immune responses.     

Cost-effectiveness of 2009 pandemic influenza A(H1N1) vaccination in the United States

Background

Pandemic influenza A(H1N1) (pH1N1) was first identified in North America in April 2009. Vaccination against pH1N1 commenced in the U.S. in October 2009 and continued through January 2010. The objective of this study was to evaluate the cost-effectiveness of pH1N1 vaccination.

Methodology

A computer simulation model was developed to predict costs and health outcomes for a pH1N1 vaccination program using inactivated vaccine compared to no vaccination. Probabilities, costs and quality-of-life weights were derived from emerging primary data on pH1N1 infections in the US, published and unpublished data for seasonal and pH1N1 illnesses, supplemented by expert opinion. The modeled target population included hypothetical cohorts of persons aged 6 months and older stratified by age and risk. The analysis used a one-year time horizon for most endpoints but also includes longer-term costs and consequences of long-term sequelae deaths. A societal perspective was used. Indirect effects (i.e., herd effects) were not included in the primary analysis. The main endpoint was the incremental cost-effectiveness ratio in dollars per quality-adjusted life year (QALY) gained. Sensitivity analyses were conducted.

Results

For vaccination initiated prior to the outbreak, pH1N1 vaccination was cost-saving for persons 6 months to 64 years under many assumptions. For those without high risk conditions, incremental cost-effectiveness ratios ranged from $8,000–$52,000/QALY depending on age and risk status. Results were sensitive to the number of vaccine doses needed, costs of vaccination, illness rates, and timing of vaccine delivery.

Conclusions

Vaccination for pH1N1 for children and working-age adults is cost-effective compared to other preventive health interventions under a wide range of scenarios. The economic evidence was consistent with target recommendations that were in place for pH1N1 vaccination. We also found that the delays in vaccine availability had a substantial impact on the cost-effectiveness of vaccination.     

Vaccination of the elderly: an update

Vaccination of the elderly still requires attention. The vaccination coverage for tetanus, influenza and pneumococcal infections is merely 40, 60 and 30%, respectively. Besides a reduction in mortality (67%) and a reduction of hospitalisation for pneumonia and influenza (50%), vaccination against influenza also results in a decrease in cardio- and cerebrovascular morbidity (20%) as well as in a decrease in the frequency of doctor visits for respiratory infections for COPD patients. Vaccination of children and health care personnel can further reduce transmission of influenza and subsequent influenza related complications in the elderly. Pneumococcal invasive disease can be reduced by 50% through vaccination. Vaccination of children with the conjugate vaccine can further reduce the incidence of pneumococcal invasive disease in the elderly. Further improvements in vaccine coverage levels are needed, mainly among elderly persons, children and persons at increased risk.     

Review. Context-induced relapse to drug seeking: a review

In humans, exposure to environmental contexts previously associated with drug intake often provokes relapse to drug use, but the mechanisms mediating this relapse are unknown. Based on early studies by Bouton & Bolles on context-induced 'renewal' of learned behaviours, we developed a procedure to study context-induced relapse to drug seeking. In this procedure, rats are first trained to self-administer drug in one context. Next, drug-reinforced lever responding is extinguished in a different (non-drug) context. Subsequently, context-induced reinstatement of drug seeking is assessed by re-exposing rats to the drug-associated context. Using variations of this procedure, we and others reported reliable context-induced reinstatement in rats with a history of heroin, cocaine, heroin-cocaine combination, alcohol and nicotine self-administration. Here, we first discuss potential psychological mechanisms of context-induced reinstatement, including excitatory and inhibitory Pavlovian conditioning, and occasion setting. We then summarize results from pharmacological and neuroanatomical studies on the role of several neurotransmitter systems (dopamine, glutamate, serotonin and opioids) and brain areas (ventral tegmental area, accumbens shell, dorsal striatum, basolateral amygdala, prefrontal cortex, dorsal hippocampus and lateral hypothalamus) in context-induced reinstatement. We conclude by discussing the clinical implications of rat studies on context-induced reinstatement of drug seeking.     

Vasopressin neuropeptides and acquisition of heroin and cocaine self-administration in rats

The effect of the vasopressin neuropeptide des-glycinamide (Arg8)-vasopressin (DGAVP) on reducing the acquisition of intravenous heroin self-administration in rats was analyzed. When rats reduced in body weight were allowed to self-administer heroin for 1 h per day in the presence of a fixed time, non contingent food delivery schedule, it appeared that heroin intake was related in an orderly way to the unit dose of heroin delivered. DGAVP decreased heroin intake during days 4 and 5 of acquisition, especially when a high dose of heroin was delivered. DGAVP decreased heroin intake more effectively when rats were tested without the food delivery schedule and for 6 h instead of 1 h sessions per day. Structure activity relationship studies revealed that the peptide (pGlu4, Cyt6)AVP-(4-8) was the shortest active sequence mimicking the effect of DGAVP and that this peptide was somewhat more potent than DGAVP in this respect. The peptide (pGlu4,Cyt6)AVP-(4-9) increased the heroin intake of the rats. DGAVP and (pGlu4,Cyt6)-AVP-(4-8) also decreased cocaine intake of body weight reduced rats given the opportunity to self-administer cocaine intravenously in daily 6 h sessions. It is concluded that vasopressin neuropeptides may decrease the reinforcing efficacy of heroin and cocaine during acquisition of drug self-administration rather than interact with nutritional and environmental factors influencing drug taking behavior.     

Antioxidant Enzyme and Element Status in Heroin Addiction or Heroin Withdrawal in Rats: Effect of Melatonin and Vitamin E Plus Se

Heroin use, withdrawal syndrome, and heroin-related deaths are still the most serious public health problems. Antioxidants and bio-elements are essential for metabolism in living organisms. To our knowledge, there are no data about the effect of antioxidant therapy on the levels of bio-elements and antioxidant enzymes in the naloxone (NX)-induced heroin withdrawal syndrome. Therefore, in the present study for the first time, we have investigated the role of antioxidant therapy, melatonin, and vitamin E plus Se, on the trace and major elements and antioxidant enzymes in the heroin addiction or heroin withdrawal in rats. Glutathione peroxidase levels were increased and catalase levels were decreased in the all study groups when compared to the sham group. The level of superoxide dismutase (SOD) in the fixed dose of heroin (FDH) given group was lower; however, in the variable doses of heroin (VDH) given group SOD level was higher. Furthermore, in withdrawal syndrome, Fe, Mg, Mn, and Ti levels were diminished and Al, Ca, and Cu levels were increased in the FDH+NX group. Moreover, Mg, Mn, and Se levels were also diminished and Al level was increased in the VDH+NX group. In conclusion, our results obviously indicated that heroin effected both bio-element status and antioxidant enzyme activities and, exogenous melatonin or vE+Se therapy might relieve on the element and antioxidant enzyme the destructive activity caused by heroin.     

A morphine/heroin vaccine with new hapten design attenuates behavioral effects in rats

Heroin use has seriously threatened public heath in many countries, but the existing therapies continue to have many limitations. Recently, immunotherapy has shown efficacy in some clinical studies, including vaccines against nicotine and cocaine, but no opioid vaccines have been introduced in clinical studies. The development of a novel opioid antigen designed specifically for the prevention of heroin addiction is necessary. A morphine-keyhole limpet hemocyanin conjugate was prepared and administered subcutaneously in rats. Antibody titers in plasma were measured using an enzyme-linked immunosorbent assay (ELISA). Competitive ELISA was used to assess the selectivity of the antibodies. Dopamine concentrations in the nucleus accumbens in rats after vaccine administration were determined by high-performance liquid chromatography with electrochemical detection. The effects of the vaccine on the heroin-primed restatement of self-administration and locomotor sensitization were evaluated. A novel hapten, 6-glutarylmorphine, was produced, and the vaccine generated a high antibody titer response. This vaccine displayed specificity for both morphine and heroin, but the anti-morphine antibodies could not recognize dissimilar therapeutic opioid compounds, such as buprenorphine, methadone, naloxone, naltrexone, codeine, and nalorphine. The morphine antibody significantly decreased morphine-induced locomotor activity in rats after immunization. Importantly, rats immunized with this vaccine did not exhibit heroin-primed reinstatement of heroin seeking when antibody levels were sufficiently high. The vaccine reduced dopamine levels in the nucleus accumbens after morphine administration, which is consistent with its behavioral effects. These results suggest that immunization with a novel vaccine is an effective means of inducing a morphine-specific antibody response that is able to attenuate the behavioral and psychoactive effects of heroin.     

Understanding reduced rotavirus vaccine efficacy in low socio-economic settings

Introduction

Rotavirus vaccine efficacy ranges from >90% in high socio-economic settings (SES) to 50% in low SES. With the imminent introduction of rotavirus vaccine in low SES countries, understanding reasons for reduced efficacy in these settings could identify strategies to improve vaccine performance.

Methods

We developed a mathematical model to predict rotavirus vaccine efficacy in high, middle and low SES based on data specific for each setting on incidence, protection conferred by natural infection and immune response to vaccination. We then examined factors affecting efficacy.

Results

Vaccination was predicted to prevent 93%, 86% and 51% of severe rotavirus gastroenteritis in high, middle and low SES, respectively. Also predicted was that vaccines are most effective against severe disease and efficacy declines with age in low but not high SES. Reduced immunogenicity of vaccination and reduced protection conferred by natural infection are the main factors that compromise efficacy in low SES.

Discussion

The continued risk of severe disease in non-primary natural infections in low SES is a key factor underpinning reduced efficacy of rotavirus vaccines. Predicted efficacy was remarkably consistent with observed clinical trial results from different SES, validating the model. The phenomenon of reduced vaccine efficacy can be predicted by intrinsic immunological and epidemiological factors of low SES populations. Modifying aspects of the vaccine (e.g. improving immunogenicity in low SES) and vaccination program (e.g. additional doses) may bring improvements.     

Heroin affects purine nucleotides catabolism in rats in vivo

To investigate the effect of heroin on purine nucleotides catabolism, a rat model of heroin administration and withdrawal was established. Concentrations of uric acid, creatinine, and urea nitrogen in plasma and ADA in plasma, brain, liver, and small intestine were tested. When two heroin administration groups were compared with the control group, the concentrations of plasma uric acid and ADA in plasma, brain, liver, and small intestine increased, whereas the plasma urea nitrogen concentrations in two heroin administration groups and the plasma creatinine concentration in the 3-day heroin administration group did not increase. It seemed that heroin exposure for a short time did not affect renal clearance rate notably. When two withdrawal groups were compared with two heroin administration groups, the concentrations of plasma uric acid and ADA in liver and small intestine decreased, but there was no significant reduction in ADA concentrations of the brain, while the plasma ADA concentrations in the two withdrawal groups were significantly higher than those of two heroin administration groups. When the two withdrawal groups were compared with the control group, there was no significant difference in the concentrations of plasma uric acid and ADA in liver and small intestine, while the concentrations of ADA in plasma and brain were still higher than those of the control group. The results imply that heroin administration may enhance the catabolism of purine nucleotides in the brain and other tissues by increased concentration of ADA and the effect may last for a long time in the brain.     

Impact of vaccination on selected diseases in Canada

Vaccination has dramatically reduced the morbidity and mortality rates of a number of diseases. The crucial element of vaccination programs is commitment to widespread coverage and to containment of outbreaks. Vaccines have led to virtual elimination of poliomyelitis and promise to eliminate measles. The incidence of congenital rubella syndrome will probably only be diminished if vaccination is extended to all 1-year-olds and susceptible prepubertal girls. The employment of diphtheria toxoid is one of the great success stories in public health. The incidence of pertussis has declined because of the diphtheria-pertussis-tetanus (DPT) vaccine given to infants, although elimination of the disease will probably have to await development of a more potent pertussis antigen. A remarkable reduction in the incidence of tetanus and tuberculosis has also been achieved.     

Vaccine regulations in Croatia

In this paper legal prerequisites for vaccine licensure in Croatia are discussed. The Croatian legislation concerning vaccine licensing, marketing authorisation and utilization is reviewed. The procedures for including a vaccine into the Mandatory Childhood Vaccination Programme are also discussed with focus on Human papillomavirus (HPV) vaccines. Non-obligatory vaccination recommendations are given when according to professional opinion; vaccination is beneficial for the vaccinee. There is little doubt that HPV vaccines should be recommended for preadolescent girls in Croatia. However, reaching a decision on its possible introduction into the Childhood Vaccination Programme will require careful consideration of the larger picture and a comparison of the cost-effectiveness of a mandatory vaccination against other competing public health priorities.     

Will vaccinated women attend cervical screening? A population based survey of human papillomavirus vaccination and cervical screening among young women in Victoria,Australia

Objectives: To assess human papillomavirus (HPV) vaccination coverage and attitudes to vaccination and Pap screening in young women. Design: Population-based telephone survey. Setting: Victoria, Australia. Participants: 234 women resident in Victoria aged 18–28 years in May 2009. Main outcome measures: Self-reported HPV vaccination uptake, reasons for non-receipt or failure to complete vaccination, knowledge and attitudes about HPV vaccination and Pap screening, and cervical screening intentions. Results: The response rate for eligible households was 62.4%. Half of the women (56%, n = 131) had previously had a Pap test and 74% (age standardised estimate) had received HPV vaccine. Of the vaccinated women, 5% had received one dose only, 18% two doses and 76% had completed the course (1.7% unsure of number of doses). Vaccination uptake was highest in the youngest women (declining from 90% for at least one dose in women aged 18–38.5% in women aged 28; p for trend <0.001). Among women who had heard of the vaccine, 96% knew Pap tests were still needed after it, although 20% thought the vaccine could prevent all cervical cancers and 9% thought the vaccine could treat cervical abnormalities and cancer. Among vaccinated women, 8% of women agreed that having been vaccinated made them less likely to have Pap tests in the future. Conclusions: Self-reported coverage in this sample was higher than that recorded on the national vaccination register. Young women report the message that Pap tests are required after vaccination, but there are gaps in their knowledge about the limitations of the vaccine so it remains to be seen if they actually follow through with having Pap tests. Ongoing monitoring of cervical screening rates will be important as this cohort ages.     

Acute Heroin Fatalities in San Francisco Demographic and Toxicologic Characteristics

The mortality rate due to heroin overdosage in San Francisco has increased dramatically since 1968 and now stands as one of the highest in the United States. While the numbers of heroin fatalities in many eastern United States cities have declined substantially in the past few years, the figures for San Francisco and the other West Coast areas continue to increase. The group of heroin overdose victims from the 1970 through 1973 period is more predominantly Caucasian and younger than from the 1963 through 1965 period. In nearly all of the victims, the presence of morphine (a heroin metabolite) was noted in bile or urine, and in about half the results of blood alcohol tests were positive. Measurement of blood morphine concentrations in the victims showed no significant difference from the concentrations noted in a control group of heroin addicts dying from causes other than overdosage.     

The effect of tularemia vaccine on the radioresistance of white rats exposed to x-irradiation

A single epicutaneous vaccination of Wistar rats with tularemic live vaccine 15 days before X-irradiation with doses of 6.0, 8.0 and 2.0 + 6.0 Gy was shown to increase their radioresistance. With higher doses (up to 8.0 Gy) the effect of the vaccine was less pronounced.