Hexarelin targets neuroinflammatory pathways to preserve cardiac morphology and function in a mouse model of myocardial ischemia-reperfusion

Acute myocardial ischemia and reperfusion injury (IRI) underly the detrimental effects of coronary heart disease on the myocardium. Despite the ongoing advances in reperfusion therapies, there remains a lack of effective therapeutic strategies for preventing IRI. Growth hormone secretagogues (GHS) have been demonstrated to improve cardiac function, attenuate inflammation and modulate the autonomic nervous system (ANS) in models of cardiovascular disease. Recently, we demonstrated a reduction in infarct size after administration of hexarelin (HEX), in a murine model of myocardial infarction. In the present study we employed a reperfused ischemic (IR) model, to determine whether HEX would continue to have a cardioprotective influence in a model of higher clinical relevance. Myocardial ischemia was induced by transient ligation of the left descending coronary artery (tLAD) in C57BL/6 J mice followed by HEX (0.3 mg/kg/day; n = 20) or vehicle (VEH) (n = 18) administration for 21 days, first administered immediately prior-to reperfusion. IR-injured and sham mice were subjected to high-field magnetic resonance imaging to assess left ventricular (LV) function, with HEX-treated mice demonstrating a significant improvement in LV function compared with VEH-treated mice. A significant decrease in interstitial collagen, TGF-β1 expression and myofibroblast differentiation was also seen in the HEX-treated mice after 21 days. HEX treatment shifted the ANS balance towards a parasympathetic predominance; combined with a significant decrease in cardiac troponin-I and TNF-α levels, these findings were suggestive of an anti-inflammatory action on the myocardium mediated via HEX. In this model of IR, HEX appeared to rebalance the deregulated ANS and activate vagal anti-inflammatory pathways to prevent adverse remodelling and LV dysfunction. There are limited interventions focusing on IRI that have been successful in improving clinical outcome in acute myocardial infarction (AMI) patients, this study provides compelling evidence towards the translational potential of HEX where all others have largely failed.

Heavy Drinking among Women Receiving Intensive Motivational Interviewing: 6-Month Outcomes

Compared to men, women with alcohol use disorders experience more severe consequences related to drinking. Intensive Motivational Interviewing (IMI) is a new 9-session version of Motivational Interviewing (MI) designed for women with alcohol use disorders. The current study reports outcomes from a randomized clinical trial of IMI compared to a single session of MI. Data were collected at baseline, 2-month, and 6-month follow-up. In addition to a standard "intent-to-treat" (ITT) analysis, we conducted disaggregated subgroup analyses of women who were heavy drinkers and a "per protocol" (PP) analysis of women in the IMI condition who attended 7-9 sessions (80% of the IMI sample). Women in both study conditions made large reductions in drinking between baseline and 2 months that were maintained at 6 months. Generalized estimating equation (GEE) models using the full sample (N = 215) did not show time by condition differences, but heavy drinkers(n = 153) receiving IMI showed significantly larger reductions in drinking at 2- and 6-month follow-up than the comparison condition. Assessment of heavy drinkers using the PP sample showed larger between condition differences favoring IMI at both follow-up time points. Results support the efficacy of IMI in terms of reducing drinking, particularly among women who are heavy drinkers.

Gabapentin Enacarbil Extended-Release for Alcohol Use Disorder: A Randomized, Double-Blind, Placebo-Controlled, Multisite Trial Assessing Efficacy and Safety

BACKGROUND

Several single-site alcohol treatment clinical trials have demonstrated efficacy for immediate-release (IR) gabapentin in reducing drinking outcomes among individuals with alcohol dependence. The purpose of this study was to conduct a large, multisite clinical trial of gabapentin enacarbil extended-release (GE-XR) (HORIZANT^® ), a gabapentin prodrug formulation, to determine its safety and efficacy in treating alcohol use disorder (AUD).

METHODS

Men and women (n = 346) who met DSM-5 criteria for at least moderate AUD were recruited across 10 U.S. clinical sites. Participants received double-blind GE-XR (600 mg twice a day) or placebo and a computerized behavioral intervention (Take Control) for 6 months. Efficacy analyses were prespecified for the last 4 weeks of the treatment period.

RESULTS

The GE-XR and placebo groups did not differ significantly on the primary outcome measure, percentage of subjects with no heavy drinking days (28.3 vs. 21.5, respectively, p = 0.157). Similarly, no clinical benefit was found for other drinking measures (percent subjects abstinent, percent days abstinent, percent heavy drinking days, drinks per week, drinks per drinking day), alcohol craving, alcohol-related consequences, sleep problems, smoking, and depression/anxiety symptoms. Common side-effects were fatigue, dizziness, and somnolence. A population pharmacokinetics analysis revealed that patients had lower gabapentin exposure levels compared with those in other studies using a similar dose but for other indications.

CONCLUSIONS

Overall, GE-XR at 600 mg twice a day did not reduce alcohol consumption or craving in individuals with AUD. It is possible that, unlike the IR formulation of gabapentin, which showed efficacy in smaller Phase 2 trials at a higher dose, GE-XR is not effective in treating AUD, at least not at doses approved by the U.S. Food and Drug Administration for treating other medical conditions.

Changes in psychiatric symptoms among persons with methamphetamine dependence predicts changes in severity of drug problems but not frequency of use

BACKGROUND

Few studies have examined how changes in psychiatric symptoms over time are associated with changes in drug use and severity of drug problems. No studies have examined these relationships among methamphetamine (MA)-dependent persons receiving motivational interviewing within the context of standard outpatient treatment.

METHODS

Two hundred seventeen individuals with MA dependence were randomly assigned to a standard single session of motivational interviewing (MI) or an intensive 9-session model of MI. Both groups received standard outpatient group treatment. The Addiction Severity Index (ASI) and timeline follow-back (TLFB) for MA use were administered at treatment entry and 2-, 4-, and 6-month follow-ups.

RESULTS

Changes in ASI psychiatric severity between baseline and 2 months predicted changes in ASI drug severity during the same time period, but not changes on measures of MA use. Item analysis of the ASI drug scale showed that psychiatric severity predicted how troubled or bothered participants were by their drug us, how important they felt it was for them to get treatment, and the number of days they experienced drug problems. However, it did not predict the number days they used drugs in the past 30 days. These associations did not differ between study conditions, and they persisted when psychiatric severity and outcomes were compared across 4- and 6-month time periods.

CONCLUSIONS

Results are among the first to track how changes in psychiatric severity over time are associated with changes in MA use and severity of drug problems. Treatment efforts targeting reduction of psychiatric symptoms among MA-dependent persons might be helpful in reducing the level of distress and problems associated with MA use but not how often it is used. There is a need for additional research describing the circumstances under which the experiences and perceptions of drug-related problems diverge from frequency of consumption.

A cognitive behavioral therapy-based text messaging intervention for methamphetamine dependence

Psychosocial treatments for methamphetamine dependence are of limited effectiveness. Thus, a significant need exists for add-on therapy for this substance user disorder. The aim of this study was to develop and test a novel text messaging intervention for use as an adjunct to cognitive behavioral group therapy for methamphetamine users. Text messaging has the potential to support patients in real-time, around the clock. We convened two meetings of an expert panel, held three focus groups in current and former users, and conducted 15 semi-structured interviews with in-treatment users in order to develop a fully automated, cognitive behavioral therapy-based text messaging intervention. We then conducted a randomized, crossover pre-test in five users seeking treatment. Participants' ratings of ease of use and functionality of the system were high. During the pre-test, we performed real-time assessments via text messaging on daily methamphetamine use, craving levels, and the perceived usefulness of messages; 79% of scheduled assessments were collected. The odds of messages being rated as "very" or "extremely" useful were 6.6 times (95% CI: 2.2, 19.4) higher in the active vs. placebo periods. The intervention is now ready for testing in randomized clinical trials.

Gender Differences in Psychiatric Symptoms among Methamphetamine Dependent Residents in Sober Living Houses

OBJECTIVES

Although psychiatric symptoms among methamphetamine (MA) dependent individuals have been studied in treatment programs, they have not been examined in services designed to support sustained recovery in the community (e.g. sober living houses). In addition, some disorders more common among women, such as somatoform and bulimia, have been understudied among MA dependent individuals. This study aimed to examine psychiatric symptom differences between MA dependent men and women who we entering sober living houses (SLHs).

METHODS

Two hundred forty five individuals were interviewed within one week of entering SLHs. Instruments included a DSM IV based measure for MA dependence, a psychiatric screen (the Psychiatric Diagnostic Screening Questionnaire), demographics, recent substance use and recent use of services.

RESULTS

Of the 245 participants, 103 men and 25 women met criteria for MA dependence. Womenwith MA dependence reported more psychiatric symptoms than men. They also trended toward reporting more psychiatric symptoms than non-MA dependent women. For men, psychiatric symptoms did not vary between those with and without MA dependence. Some understudied disorders (e.g., somatoform) had large proportions of women meeting the screening criteria.

CONCLUSIONS

Additional research is needed on understudied psychiatric disorders that are common among MA dependent women. SLH's should consider ways to address psychiatric symptoms among MA dependent individuals, especially women. Strategies could include increasing linkages with professional mental health services as well as developing peer oriented strategies for managing symptoms.

Developing biomarkers for methamphetamine addiction

There are an estimated 11.7 million methamphetamine (MA) abusers in the United States and epidemics of MA addiction are occurring worldwide. In our human laboratory and outpatient clinical trials we use innovative methods to quantify the severity of MA addiction and test biomarkers that may predict response to therapy or risk of relapse. One potential biomarker of addiction is the quantity of abused drug intake. Qualitative urinalysis is used in clinical trials and during treatment but provides only a binary outcome measure of abuse. Using non-pharmacologic doses of deuterium labeled l-MA we have developed a continuous quantitative measure to estimate the bioavailable amount of MA addicts ingest. Brain Derived Neurotrophic Factor is a neurotrophin that encourages growth and differentiation of new neurons and synapses. Low BDNF levels are seen in many addictive disorders and BDNF is elevated in recovering MA addicts, suggesting BDNF may be a marker of MA addiction. We are investigating the effects of controlled doses of MA on BDNF levels and gene regulation and measuring BDNF in our clinical trials. We believe both patients and clinical researches will benefit from the addition of new, objective and quantifiable outcome measures that reflect disease severity and recovery from addiction.

What did we learn from our study on sober living houses and where do we go from here?

Lack of a stable, alcohol- and drug-free living environment can be a serious obstacle to sustained abstinence. Destructive living environments can derail recovery for even highly motivated individuals. Sober living houses (SLHs) are alcohol- and drug-free living environments for individuals attempting to abstain from alcohol and other drugs. They are not licensed or funded by state or local governments and the residents themselves pay for costs. The philosophy of recovery emphasizes 12-Step group attendance and peer support. We studied 300 individuals entering two different types of SLHs over an 18-month period. This article summarizes our published findings documenting resident improvement on measures of alcohol and drug use, employment, arrests, and psychiatric symptoms. Involvement in 12-Step groups and characteristics of the social network were strong predictors of outcome, reaffirming the importance of social and environmental factors in recovery. This article adds to our previous reports by providing a discussion of implications for treatment and criminal justice systems. We also describe the next steps in our research on SLHs, which will include: (1) an attempt to improve outcomes for residents referred from the criminal justice system and (2) a depiction of how attitudes of stakeholder groups create a community context that can facilitate and hinder the legitimacy of SLHs as a recovery modality.

Substance use and motivation: a longitudinal perspective

BACKGROUND

Motivation to change substance use behavior is an important component of the recovery process that has usually been studied at entry into treatment. Less studied, but equally important, is the measurement of motivation over time and the role motivation plays in subsequent substance use.

OBJECTIVES

The present study sought to examine longitudinal motivation toward sobriety among residents of sober living houses.

METHODS

Sober living residents (n = 167) were followed at 6-month intervals over an 18-month period and assessed for motivation and substance use outcomes at each study interview. Motivation was measured using the costs and benefits subscales of the Alcohol and Drug Consequences Questionnaire (ADCQ) and substance use outcomes included the Addiction Severity Index (ASI) alcohol scale, ASI drug scale, and peak density of substance use (number of days of most use in a month).

RESULTS

Participants reported higher benefits than costs of sobriety or cutting down substance use at every study time point. Using lagged generalized estimating equation models, the ADCQ costs predicted increased severity for alcohol, drugs, and peak density, whereas the benefits subscale predicted decreased drug and peak density.

CONCLUSION

Longitudinal measurement of motivation can be a useful clinical tool to understand later substance use problems.

SCIENTIFIC SIGNIFICANCE

Given the mixed findings from prior studies on the effects of baseline motivation, a shift toward examining longitudinal measures of motivation at proximal and temporal intervals is indicated.

Eighteen Month Outcomes for Clients Receiving Combined Outpatient Treatment and Sober Living Houses

One of the most frequent and frustrating challenges facing clients in outpatient treatment is finding a living environment that is free of alcohol and drugs and supportive of recovery. Sober Living Houses (SLHs) have been suggested as one potential solution (Polcin, 2009). Among other advantages, SLHs are financially self-sustaining and residents can remain there as long as they wish, provided they comply with house rules and expectations. This study examined 18-month outcomes for 55 individuals receiving outpatient treatment combined with residence in a SLH. Repeated measures analyses comparing 6-month time periods showed significant improvement on measures of alcohol and drug use, arrests, and days worked. The Addiction Severity Index (ASI) showed significant improvement on legal and employment scales. On ASI alcohol and drug scales, individuals entered SLHs with very low severity that was maintained at 18 months. Involvement in 12-step groups was associated with reductions in alcohol and drug use.

Sober living houses for alcohol and drug dependence: 18-month outcomes

OBJECTIVE

A major challenge facing many individuals attempting to abstain from substances is finding a stable living environment that supports sustained recovery. Sober living houses (SLHs) are alcohol- and drug-free living environments that support abstinence by emphasizing involvement in 12-step groups and social support for recovery. Among a number of advantages, they are financially self-sustaining and residents can stay as long as they wish. Although SLHs can be used as housing referrals after inpatient treatment, while clients attend outpatient treatment, after incarceration, or as an alternative to treatment, they have been understudied and underutilized.

METHOD

To describe outcomes of SLH residents, we interviewed 245 individuals within 1week of entering SLHs and at 6-, 12-, and 18-month follow-up. Eighty-nine percent completed at least one follow-up interview. Outcomes included the Addiction Severity Index (ASI), Brief Symptom Inventory (BSI), and measures of alcohol and drug use. Covariates included demographic characteristics, 12-step involvement, and substance use in the social network.

RESULTS

Regardless of referral source, improvements were noted on ASI scales (alcohol, drug, and employment), psychiatric severity on the BSI, arrests, and alcohol and drug use. Substance use in the social network predicted nearly all outcome measures. Involvement in 12-step groups predicted fewer arrests and lower alcohol and drug use.

CONCLUSION

Residents of SLHs made improvements in a variety of areas. Additional studies should use randomized designs to establish causal effects of SLHs. Results support the importance of key components of the recovery model used by SLHs: (a) involvement in 12-step groups and (b) developing social support systems with fewer alcohol and drug users.

October 1996--rapidly progressive weakness

One week after a flu-like illness, a 51-year-old woman developed rapidly progressive weakness. Within three weeks, she required mechanical ventilation. A neurological exam revealed severe motor involvement with normal sensory findings confirmed by nerve conduction studies. Five days after intubation a catastrophic brain hemorrhage occurred. Autopsy showed severe loss of axons in the motor roots with periaxonal macrophages and no lymphocytes. These findings are typical of acute motor axonal neuropathy, which is rare in the United States.

Neuropathy associated with hyperoxaluria: improvement after combined renal and liver transplantations

Little is known about oxaluria-associated neuropathy, and no effective treatments have been described. We report two patients with clinically severe and progressive sensorimotor polyneuropathy associated with oxaluria. Electrodiagnostic testing and sural nerve histopathology revealed evidence of severe axon loss and demyelination. In addition, birefringent crystalline deposits were identified within endoneurial and perineurial blood vessel walls, axon cylinders, and perimysial blood vessel walls. Electron probe microscopy confirmed that calcium (consistent with calcium oxalate) was a major constituent of the crystals. Both patients had substantial improvement in neuropathic signs and symptoms after kidney and liver transplantations despite no prior improvement with hemodialysis. Our results confirm previous reports of a mixed axonal and demyelinating neuropathy with calcium oxalate deposition in association with oxaluria. In addition, our findings suggest that renal and liver transplantation may be potential treatments for the associated neuropathy.

A randomised study of "wet wraps" versus conventional treatment for atopic eczema

AIMS

To compare two treatments in common usage for children with atopic eczema: "wet wrap" bandages versus conventional topically applied ointments.

METHODS

A total of 50 children (age 4-27 months) with moderate to severe eczema were randomised to one or other treatment. Two research nurses supervised the study. The first gave advice and support, and the second, blinded to the treatment modality being used, scored the change in eczema severity over a period of four weeks using the SCORAD eczema severity scale.

RESULTS

Both treatments gave a benefit in overall SCORAD scores (mean change for wet wrap group was 53 to 24; for the conventional group, 41 to 17). There was no significant difference between the two groups in terms of overall improvement at four weeks or in the timescale of improvements. The amount of topical of topical steroid used was similar in both groups. The wet wrap group suffered significantly more skin infections requiring antibiotics. Carers reported that wet wraps were less easy to apply than conventional treatment.

A multi-site dose ranging study of nalmefene in the treatment of alcohol dependence

The opiate antagonist nalmefene has been shown in 2 single-site studies to reduce alcohol consumption and relapse drinking in alcohol-dependent individuals. This safety and preliminary multisite efficacy study evaluated 3 doses of nalmefene (5, 20, or 40 mg) in a double-blind comparison to placebo over a 12-week treatment period in 270 recently abstinent outpatient alcohol-dependent individuals. Participants concomitantly received 4 sessions of a motivational enhancement therapy (with a medication compliance component) delivered from trained counselors. Although more subjects in the active medication groups terminated the study early secondary to adverse events, the rates did not differ significantly from that of placebo. The 20-mg/d group experienced more insomnia, dizziness, and confusion, while the 5-mg group also had more dizziness and the 40-mg group had more nausea than the placebo group. Most of these symptoms were mild and improved over time. Although all subjects had a reduction in heavy drinking days, craving, gamma-glutamyl transferase, and carbohydrate-deficient transferrin concentrations over the course of the study, there was no difference between the active medication and placebo groups on these measures. The time to first heavy drinking day was also not significantly different between the placebo and the active treatment groups. This relatively small multisite trial showed that nalmefene was reasonably well tolerated in recently abstinent alcoholics. However, possibly because of variation among the sites or the comparatively small sample size, there was no evidence of superior efficacy outcomes with nalmefene treatment.

Neurology patient education materials: do our educational aids fit our patients' needs?

The purpose of this study was to assess the suitability of various neurology patient education brochures, as well as neurology information on the World Wide Web, to determine whether they were appropriate for patients with low literacy. A convenience sample of 520 patients in university-based public and private neurology clinics participated. In this cross-sectional study, the patients' reading levels were assessed by using the Rapid Estimate of Adult Literacy in Medicine. Forty-three patient education materials were assessed for reading level by using the Fog Index and for suitability characteristics (including content, type and relevance of graphics, layout, type size and fonts, and motivating qualities) by using the Suitability Assessment of Materials. The mean education level of patients was 12th grade; however, the mean reading level was 7th-8th grade. Of the assessed materials, 91% were written at a 9th-grade level or above, even though only 58% of patients read at a 9th-grade level. Only 14% of the materials were considered to have superior suitability, whereas 58% were adequate, and 28% were determined not suitable. Thus, the available neurology patient education aids are not matched to the patient population or to the average U.S. reading levels. Ideally, information needs to be written at a 9th-grade level or below. Instructional graphics, simpler words, patient interaction, and cultural sensitivity improve material suitability.

A descriptive analysis of participant characteristics and patterns of substance use in the CSAT methamphetamine treatment project: the first six months

The CSAT Methamphetamine Treatment Project (MTP) is a multisite study with a two-fold purpose: to assess the feasibility and outcomes generated by a technology transfer of the Matrix treatment model for methamphetamine (MA) abuse into several community-based treatment programs, and specifically to compare outcomes of treatment as usual at each site with outcomes of the Matrix model, as implemented in each site. The study comprises seven sites, geographically situated in Hawaii, Northern and Southern California, and Montana. This article presents a demographic description of the cohort, and describes patterns of drug use, abuse, and related problems among the 169 participants recruited in the first six months of the study, from April through September 1999. Specific analyses presented include: demographic composition of the sample with respect to gender, age, ethnicity, education completed, employment status, and income; primary drug used, and mean percent of days using various drugs including MA, alcohol, and marijuana; and percent of sample reporting various routes of drug administration. Mean baseline Addiction Severity Index composite scores are presented that describe medical, employment, alcohol, drug, legal, family/social, and psychiatric status for the sample. Also presented here are comparisons of this preliminary population to other populations reported in the literature. This early subset of MTP participants is similar to other methamphetamine-abusing populations described in the literature in age, years of education, income, and mean years of use. However, because of its multisite structure and the locations of its constituent sites, the MTP population has greater variation in ethnic makeup than do populations from other studies, offering an opportunity to provide useful new information about drug use patterns and treatment responses in populations not previously studied.

Transient blindness associated with reversible occipital white matter abnormalities: two patients studied by MR, CT, and 18F-FDG PET imaging

Reversible, multifocal hyperintense T2 signal abnormalities were noted within the occipital and posterior parietal subcortical white matter in a previously healthy 59-year-old right-handed woman with acute onset of cortical blindness and seizures. Repeat brain magnetic resonance imaging and a positron emission tomographic scan of 18F-fluorodeoxyglucose brain uptake performed 2 months after the ictal event failed to reveal any abnormality. This patient is similar to a 57-year-old female who developed severe headache and magnetic resonance signal abnormalities in the subcortical white matter of both occipital lobes, which later normalized, as judged by correlative, sequential computed tomographic examinations. This study emphasizes that an increasingly more frequent phenomenon of reversible MRI signal abnormalities can occur within the occipital subcortical white matter in acutely ill individuals, and not be associated with any lasting abnormalities on clinical examination or on radiological imaging studies such as computed tomography, magnetic resonance imaging, or positron emission tomography.

Changes in the hippocampus induced by glucose in thiamin deficient rats detected by MRI

Using T2-weighted Magnetic Resonance Imaging (MRI) in a pyrithiamin-treated, thiamin deficient (TD) rat model of Wernicke's encephalopathy (WE), we have observed hyperintensity in the thalamus, hypothalamus, collicular bodies and hippocampus which was enhanced 40 min after a glucose load. Hyperintensity was not evident in these structures in thiamin replete rats receiving glucose nor was it enhanced in TD rats administered 2-deoxyglucose. Residual hyperintensity was still evident in the hippocampus as long as 30 days after thiamin administration and was increased by repeat glucose challenge at that time. These data indicate that the hippocampus is as vulnerable as the thalamus to some persistent pathological change when glucose is metabolised in a state of thiamin deficiency.

Amphetamine, not MDMA, is associated with intracranial hemorrhage

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Hyperkalemic periodic paralysis: rapid molecular diagnosis and relationship of genotype to phenotype in 12 families

We studied mutations of the adult voltage-gated skeletal muscle sodium channel gene in 12 families, from diverse ethnic backgrounds, with hyperkalemic periodic paralysis (HyperPP). We describe a novel procedure, using ligase chain reaction (LCR), to simultaneously identify two different point mutations (previously described) and one rare, apparently benign polymorphism that results in a nonconservative amino acid substitution. Three of 12 families showed the Met1592Val mutation, and six of 12 had the Thr704Met mutation. The mutation in three of the 12 families was not identified. In one of these three families, the disease was not linked to the adult voltage-gated sodium channel gene, suggesting the existence of a clinically similar but genetically distinct form of HyperPP. Genotype/phenotype correlations based on patient records and interviews in these families showed the variable and subjective nature of the illness, although the clinical distinctions between hyperkalemic periodic paralysis and paramyotonia congenita were reinforced by the molecular data.

Sternohyoid muscle biopsy. A diagnostic technique in respiratory failure of neuromuscular origin

Patients with neuromuscular disease may develop respiratory failure requiring mechanical ventilation. We describe a sternohyoid muscle biopsy technique as a diagnostic aid in such patients undergoing tracheostomy for prolonged ventilatory support. The biopsy procedure is quick and without added discomfort or morbidity for the patient. Our preliminary observations in three patients suggest that the sternohyoid muscle biopsy may be a useful diagnostic tool in this selected group of patients.

Muscle metabolism in patients with peripheral vascular disease investigated by 31P nuclear magnetic resonance spectroscopy

Eleven men with claudication and ten control subjects had calf muscle metabolism studied at rest and during exercise and the subsequent recovery period by 31P nuclear magnetic resonance (n.m.r.) spectroscopy. The muscle of patients with severe claudication had a significantly greater depletion of phosphocreatine and fall in pH during exercise and a slower recovery of phosphocreatine and pH after exercise. The muscle of patients with both mild and severe disease had slower rates of ADP recovery after exercise than that of control subjects. Surgical correction of the associated arterial stenosis abolished claudication and led to correction of the metabolic abnormalities in two patients. Claudication pain was not related to intracellular pH or concentration of phosphorus-containing metabolites. Energy production via oxidative metabolism is impaired but glycolysis may be increased in the calf muscle of patients with intermittent claudication.

A water calorimeter for neutron dosimetry

A water calorimeter has been used for the direct measurement of absorbed dose to water in a d(15) + Be neutron beam. The absorbed dose measured with the calorimeter was compared with that measured with an Exradin ionisation chamber, constructed of A-150 plastic. The doses measured by the ionisation chamber were calculated according to the European (ECNEU) protocol. Absorbed dose to tissue measured with the calorimeter was 4.3% lower than that measured with the ionisation chamber. Relative to ionisation chamber dosimetry, dose measurements with the calorimeter in the neutron beam were 9% lower than similar measurements in 4 and 9 MV photon beams. The significance of the results is discussed in terms of the heat defect in water.

A mitochondrial encephalomyopathy. A combined 31P magnetic resonance and biochemical investigation

A 15-year-old girl presented with recurrent encephalopathic episodes, epilepsy, myopathy and chronic lactic acidosis. A muscle biopsy revealed the presence of ragged red fibres and mitochondria with paracrystalline inclusions. Biochemical studies on freshly isolated skeletal muscle mitochondria demonstrated a deficiency of NADH-CoQ reductase activity. Investigation of her gastrocnemius muscle at rest by phosphorus nuclear magnetic resonance displayed a reduced phosphocreatine concentration with elevated levels of inorganic phosphate and ADP. Abnormalities were also apparent in her brain spectrum. It is therefore possible that the mitochondrial defect present in skeletal muscle is also being expressed in the brain.

The successful use of asialylated IgG as an immunogen and arthritogen in the rabbit

Joint lesions, closely resembling the main features of those seen in rheumatoid patients, were produced by intra-articular injections of asialylated homologous IgG into presensitized rabbits. The inflammatory changes were characterized by areas of extremely dense chronic inflammatory cell infiltration, where the lymphocytes were often aggregated into lymphoid follicles. There were also signs of involvement of the contralateral, saline-injected knee. Formation of an experimental rheumatoid factor-like antibody, detected by its ability to agglutinate sheep erythrocytes sensitized with baboon IgG, was also demonstrated. In addition, the rabbits developed other manifestations associated with rheumatoid arthritis, namely increases in erythrocyte sedimentation rate, serum haptoglobin concentration and joint size.