Plasmid cloning vectors for the conjugal transfer of DNA from Escherichia coli to Streptomyces spp

We have constructed cloning vectors for the conjugal transfer of DNA from Escherichia coli to Streptomyces spp. All vectors contain the 760-bp oriT fragment from the IncP plasmid, RK2. Transfer functions need to be supplied in trans by the E. coli donor strain. We have incorporated into these vectors selectable antibiotic-resistance markers (AmR, ThR, SpR) that function in Streptomyces spp. and other features that should allow for: (i) integration via homologous recombination between cloned DNA and the Streptomyces spp. chromosome, (ii) autonomous replication, or (iii) site-specific integration at the bacteriophage phi C31 attachment site. Shuttle cosmids for constructing genomic libraries and bacteriophage P1 cloning vector capable of accepting approx. 100-kb fragments are also described. A simple mating procedure has been developed for the conjugal transfer of these vectors from E. coli to Streptomyces spp. that involves plating of the donor strain and either germinated spores or mycelial fragments of the recipient strain. We have shown that several of these vectors can be introduced into Streptomyces fradiae, a strain that is notoriously difficult to transform by PEG-mediated protoplast transformation.

The effects of eccentric versus concentric resistance training on muscle strength and mass in healthy adults: a systematic review with meta-analysis

The aim of this systematic review was to determine if eccentric exercise is superior to concentric exercise in stimulating gains in muscle strength and mass. Meta-analyses were performed for comparisons between eccentric and concentric training as means to improve muscle strength and mass. In order to determine the importance of different parameters of training, subgroup analyses of intensity of exercise, velocity of movement and mode of contraction were also performed. Twenty randomised controlled trials studies met the inclusion criteria. Meta-analyses showed that when eccentric exercise was performed at higher intensities compared with concentric training, total strength and eccentric strength increased more significantly. However, compared with concentric training, strength gains after eccentric training appeared more specific in terms of velocity and mode of contraction. Eccentric training performed at high intensities was shown to be more effective in promoting increases in muscle mass measured as muscle girth. In addition, eccentric training also showed a trend towards increased muscle cross-sectional area measured with magnetic resonance imaging or computerised tomography. Subgroup analyses suggest that the superiority of eccentric training to increase muscle strength and mass appears to be related to the higher loads developed during eccentric contractions. The specialised neural pattern of eccentric actions possibly explains the high specificity of strength gains after eccentric training. Further research is required to investigate the underlying mechanisms of this specificity and its functional significance in terms of transferability of strength gains to more complex human movements.

A multinational examination of weight bias: predictors of anti-fat attitudes across four countries

BACKGROUND/OBJECTIVES

As rates of obesity have increased throughout much of the world, so too have bias and prejudice toward people with higher body weight (that is, weight bias). Despite considerable evidence of weight bias in the United States, little work has examined its extent and antecedents across different nations. The present study conducted a multinational examination of weight bias in four Western countries with comparable prevalence rates of adult overweight and obesity.

METHODS

Using comprehensive self-report measures with 2866 individuals in Canada, the United States, Iceland and Australia, the authors assessed (1) levels of explicit weight bias (using the Fat Phobia Scale and the Universal Measure of Bias) and multiple sociodemographic predictors (for example, sex, age, race/ethnicity and educational attainment) of weight-biased attitudes and (2) the extent to which weight-related variables, including participants' own body weight, personal experiences with weight bias and causal attributions of obesity, play a role in expressions of weight bias in different countries.

RESULTS

The extent of weight bias was consistent across countries, and in each nation attributions of behavioral causes of obesity predicted stronger weight bias, as did beliefs that obesity is attributable to lack of willpower and personal responsibility. In addition, across all countries the magnitude of weight bias was stronger among men and among individuals without family or friends who had experienced this form of bias.

CONCLUSIONS

These findings offer new insights and important implications regarding sociocultural factors that may fuel weight bias across different cultural contexts, and for targets of stigma-reduction efforts in different countries.

Weight loss in severely obese subjects prevents the progression of impaired glucose tolerance to type II diabetes. A longitudinal interventional study

OBJECTIVE

To determine if weight loss may prevent conversion of impaired glucose tolerance (IGT) to diabetes, because weight loss reduces insulin resistance. The prevalence of IGT in the U.S. population is estimated at 11.2%, more than twice that of diabetes. Furthermore, because an oral glucose tolerance test is needed for its detection, most of these patients are undiagnosed. Screening for IGT would be meaningful if progression to diabetes could be delayed or prevented.

RESEARCH DESIGN AND METHODS

For an average of 5.8 years (range 2-10 years), 136 individuals with IGT and clinically severe obesity (> 45 kg excess body weight) were followed. The experimental group included 109 patients with IGT who underwent bariatric surgery for weight loss. The control group was made up of 27 subjects with IGT who did not have bariatric surgery. The criteria of the World Health Organization was used to detect IGT and diabetes in this population. The main outcome measure of this nonrandomized control trial is the incidence density, or number of events (development of diabetes) divided by the time of exposure to risk.

RESULTS

Of the 27 subjects in the control group, 6 developed diabetes during an average of 4.8 +/- 2.5 years of postdiagnosis follow-up, yielding a rate of conversion to diabetes of 4.72 cases per 100 person-years. The 109 individuals of the experimental group were followed for an average of 6.2 +/- 2.5 years postbariatric surgery. Based on the 95% confidence interval of the comparison group, we would expect to find that between 22 and 36 subjects in the experimental group developed diabetes over the follow-up period. Only 1 of the 109 experimental-group patients developed diabetes, resulting in a conversion rate of the experimental group of only 0.15 cases per 100 person-years, which is significantly lower (P < 0.0001) than the control group.

CONCLUSIONS

Weight loss in patients with clinically severe obesity prevents the progression of IGT to diabetes by > 30-fold.

The effects of clinical case management on hospital service use among ED frequent users

This study examined the impact of case management on hospital service use, hospital costs, homelessness, substance abuse, and psychosocial problems in frequent users of a public urban emergency department (ED). Subjects were 53 patients who used the ED five times or more in 12 months. Utilization, cost, and psychosocial variables were compared 12 months before and after the intervention. The median number of ED visits decreased from 15 to 9 (P < .01), median ED costs decreased from $4,124 to $2,195 (P < .01) and median medical inpatient costs decreased from $8,330 to $2,786 (P < .01). Homelessness decreased by -57% (P < .01), alcohol use by -22% (P = .05) and drug use by -26% (P = .05). Linkage to primary care increased 74% (P < .01). Fifty-four percent of medically indigent subjects obtained Medicaid (P < .01). There was a net cost savings, with each dollar invested in the program yielding a $1.44 reduction in hospital costs. Thus, case management appears to be a cost-effective means of decreasing acute hospital service use and psychosocial problems among frequent ED users.

Systemic Candida infection in extremely low birth weight infants: short term morbidity and long term neurodevelopmental outcome

OBJECTIVE

To describe mortality, morbidity at discharge and neurodevelopmental outcome at 2 years corrected age in extremely low birth weight infants with systemic Candida infection during intensive care stay.

METHOD

We identified all extremely low birth weight (birth weight <1000 g) infants diagnosed with Candida sepsis and/or meningoencephalitis between 1988 and mid-1996 in the tertiary neonatal intensive care centers of Toronto. The outcome of the infected infants at discharge and at 2 years corrected age was compared with a cohort of 470 extremely low birth weight infants born between 1990 and 1994.

RESULTS

Forty-six extremely low birth weight infants with systemic Candida infection, mean (+/-SD) gestational age of 24.7 +/- 1.6 weeks and birth weight 699 +/- 135 g, were identified. Case fatality rate was 37% (17 of 46), not significantly different from the control group (35%). Data on 27 infected survivors were available at discharge. All had chronic lung disease compared with 33% in the control cases (P = 0.0001), a high incidence of periventricular leukomalacia (26% vs. 12%, P = 0.06) and an increase in severe retinopathy of prematurity (22% vs. 9%, P = 0.04); 60% had adverse neurologic outcomes at 2 years corrected age compared with 35% in the control group, and 41% vs. 12% had severe disabilities (P = 0.005). Cranial ultrasound examination was the only diagnostic modality in 5 of 13 (38%) cases with central nervous system Candida involvement. All infants with brain parenchymal lesions detected by cranial ultrasound had poor outcome. Early diagnosis and commencement of antifungal treatment favorably affected the outcome.

CONCLUSIONS

Systemic Candida infection is associated with increased short and long term morbidity in extremely low birth weight infants. Candida infection of the central nervous system has a significant impact on long term neurodevelopmental outcome. Performance of cranial ultrasound examination is recommended as a part of the diagnostic investigation in these infants. Detection of brain parenchymal involvement might provide further information to predict outcome.

Evidence for involvement of oxygen free radicals in bile acid toxicity to isolated rat hepatocytes

The mechanisms by which hydrophobic bile acids are toxic to the liver are unknown. To determine whether the generation of free radicals is involved in the hepatotoxicity of bile acids, freshly isolated rat hepatocytes were incubated with individual bile acids (100 to 200 mumol/L) for 4 hr. Hepatocyte viability (trypan blue exclusion) declined to 40% to 50% in incubations with taurochenodeoxycholic acid and taurolithocholic acid, whereas taurocholic acid and tauroursodeoxycholic acid were not toxic. Lipid peroxidation was significantly associated with the loss of cell viability. Preincubation with different antioxidants-D-alpha-tocopheryl succinate, D-alpha-tocopherol, diphenyl-p-phenylenediamine, superoxide dismutase, catalase, superoxide dismutase + catalase, deferoxamine or apotransferrin-protected against the loss of viability and inhibited lipid peroxidation in cells incubated with 200 mumol/L taurolithocholic acid. alpha-Tocopheryl succinate added after 90 min of incubation with taurolithocholic acid ameliorated further hepatocyte toxicity and lipid peroxidation. Incubation of hepatocytes with 500 mumol/L of taurochenodeoxycholic acid or taurolithocholic acid under a low oxygen tension (9% O2) similarly caused lipid peroxidation and cell injury that was reversed by preincubation with D-alpha-tocopherol. These data suggest that oxygen free radicals may be involved in the pathogenesis of bile acid hepatotoxicity.

The validation of the Peer Assessment Rating index for malocclusion severity and treatment difficulty

The Peer Assessment Rating (PAR) index is a British occlusal index that measures the severity of dental malocclusion and has been used in several investigations that have evaluated the effectiveness of orthodontic treatment provision in Europe. As part of its development, the PAR index was validated for malocclusion severity, by using the opinions of a panel of 74 dentists and orthodontists. The present investigation was carried out to validate the PAR index, by using the opinion of an American panel of orthodontists. Eleven orthodontists examined a sample of 200 sets of study casts and rated them for malocclusion severity and perceived treatment difficulty. Multiple regression techniques were used to evaluate the predictive power of the components of malocclusion on the panel's scores. Weightings were calculated from the partial regression coefficients and, when these weightings were applied to the PAR index, the association between the panel's opinion and the PAR index scores was increased.

Social relationships of men at risk for AIDS

Survey data collected in 1984-85 from a community sample of 637 gay and bisexual men were used to determine the features of social relationships that were most conductive to changes in both psychological health and AIDS-related sexual risk behavior. Multiple regression analyses showed that both the perceived availability of social support and the absence of conflicts in the social network were related to improve psychological health. At the same time, the subjective experience of integration into social networks was associated with increased psychological distress, and validation (the experience of being accepted by others) was related to a higher level of risk activity. These findings are discussed in terms of the social relationships among community members that share a common stressor--in this case the shared problem of being at risk for AIDS.

Perfusion measurement in brain gliomas with intravoxel incoherent motion MRI

BACKGROUND AND PURPOSE

Intravoxel incoherent motion MRI has been proposed as an alternative method to measure brain perfusion. Our aim was to evaluate the utility of intravoxel incoherent motion perfusion parameters (the perfusion fraction, the pseudodiffusion coefficient, and the flow-related parameter) to differentiate high- and low-grade brain gliomas.

MATERIALS AND METHODS

The intravoxel incoherent motion perfusion parameters were assessed in 21 brain gliomas (16 high-grade, 5 low-grade). Images were acquired by using a Stejskal-Tanner diffusion pulse sequence, with 16 values of b (0-900 s/mm(2)) in 3 orthogonal directions on 3T systems equipped with 32 multichannel receiver head coils. The intravoxel incoherent motion perfusion parameters were derived by fitting the intravoxel incoherent motion biexponential model. Regions of interest were drawn in regions of maximum intravoxel incoherent motion perfusion fraction and contralateral control regions. Statistical significance was assessed by using the Student t test. In addition, regions of interest were drawn around all whole tumors and were evaluated with the help of histograms.

RESULTS

In the regions of maximum perfusion fraction, perfusion fraction was significantly higher in the high-grade group (0.127 ± 0.031) than in the low-grade group (0.084 ± 0.016, P < .001) and in the contralateral control region (0.061 ± 0.011, P < .001). No statistically significant difference was observed for the pseudodiffusion coefficient. The perfusion fraction correlated moderately with dynamic susceptibility contrast relative CBV (r = 0.59). The histograms of the perfusion fraction showed a "heavy-tailed" distribution for high-grade but not low-grade gliomas.

CONCLUSIONS

The intravoxel incoherent motion perfusion fraction is helpful for differentiating high- from low-grade brain gliomas.

Abnormal hepatic mitochondrial respiration and cytochrome C oxidase activity in rats with long-term copper overload

BACKGROUND

Dietary copper overload in the rat is associated with morphological abnormalities and lipid peroxidation of hepatic mitochondria. This study was designed to determine if copper hepatotoxicity was associated with functional alterations in mitochondrial respiration in conjunction with lipid peroxidation.

METHODS

Weanling male rats were pair-fed for 8 weeks on diets containing normal or high levels of copper in combination with sufficient vitamin E. Serum and liver samples were obtained, and hepatic mitochondria were isolated by differential centrifugation.

RESULTS

Oxidant injury (decreased levels of hepatic glutathione and alpha tocopherol and increased levels of mitochondrial thiobarbituric acid-reacting substances) was present in the copper-overloaded rats. Serum aminotransferase levels correlated with concentrations of mitochondrial copper and thiobarbituric acid-reacting substances. Copper overload caused a decrease in state 3 respiration and the respiratory control ratio in hepatic mitochondria when several electron donors were used. Analysis of the oxidoreductase activities of the four mitochondrial electron transport protein complexes showed that complex IV (cytochrome C oxidase) activity was reduced by 60% in copper overload.

CONCLUSIONS

Functional abnormalities of mitochondria accompany lipid peroxidation and the morphological alterations caused by copper overload, supporting the hypothesis that the mitochondrion is one of the major intracellular targets in copper hepatotoxicity.

Metabolic basis of the species difference to aflatoxin B1 induced hepatotoxicity

Primary metabolism of aflatoxin B1 by the liver microsomal enzymes from a range of animal species showed both quantitative and qualitative differences. Quail was shown to have the most rapid metabolism of aflatoxin B1. The major product of metabolism in this case was found to be aflatoxin B1-8,9-dihydrodiol suggesting that the quail microsomes produced high levels of the proposed reactive intermediate aflatoxin B1-8,9-epoxide. Using this system to generate the epoxide, the ability of the cytosol prepared from each species to conjugate epoxide with reduced glutathione was investigated. Large differences in ability to conjugate were observed ranging from 0 to 72% for quail and mouse respectively. Differences in both primary and secondary metabolism of AFB1 were noted between male and female Fischer 344 rats.

Biochemical evidence for a novel low molecular weight 2-5A-dependent RNase L in chronic fatigue syndrome

Previous studies from this laboratory have demonstrated a statistically significant dysregulation in several key components of the 2',5'-oligoadenylate (2-5A) synthetase/RNase L and PKR antiviral pathways in chronic fatigue syndrome (CFS) (Suhadolnik et al. Clin Infect Dis 18, S96-104, 1994; Suhadolnik et al. In Vivo 8, 599-604, 1994). Two methodologies have been developed to further examine the upregulated RNase L activity in CFS. First, photoaffinity labeling of extracts of peripheral blood mononuclear cells (PBMC) with the azido 2-5A photoaffinity probe, [32P]pApAp(8-azidoA), followed by immunoprecipitation with a polyclonal antibody against recombinant, human 80-kDa RNase L and analysis under denaturing conditions. A subset of individuals with CFS was identified with only one 2-5A binding protein at 37 kDa, whereas in extracts of PBMC from a second subset of CFS PBMC and from healthy controls, photolabeled/immunoreactive 2-5A binding proteins were detected at 80, 42, and 37 kDa. Second, analytic gel permeation HPLC was completed under native conditions. Extracts of healthy control PBMC revealed 2-5A binding and 2-5A-dependent RNase L enzyme activity at 80 and 42 kDa as determined by hydrolysis of poly(U)-3'-[32P]pCp. A subset of CFS PBMC contained 2-5A binding proteins with 2-5A-dependent RNase L enzyme activity at 80, 42, and 30 kDa. However, a second subset of CFS PBMC contained 2-5A binding and 2-5A-dependent RNase L enzyme activity only at 30 kDa. Evidence is provided indicating that the RNase L enzyme dysfunction in CFS is more complex than previously reported.

Eukaryotic translation initiation factor 5 (eIF5) acts as a classical GTPase-activator protein

GTP hydrolysis occurs at several specific stages during the initiation, elongation, and termination stages of mRNA translation. However, it is unclear how GTP hydrolysis occurs; it has previously been suggested to involve a GTPase active center in the ribosome, although proof for this is lacking. Alternatively, it could involve the translation factors themselves, e.g., be similar to the situation for small G in which the GTPase active site involves arginine residues contributed by a further protein termed a GTPase-activator protein (GAP). During translation initiation in eukaryotes, initiation factor eIF5 is required for hydrolysis of GTP bound to eIF2 (the protein which brings the initiator Met-tRNA(i) to the 40S subunit). Here we show that eIF5 displays the hallmarks of a classical GAP (e.g., RasGAP). Firstly, its interaction with eIF2 is enhanced by AlF(4)(-). Secondly, eIF5 possesses a conserved arginine (Arg15) which, like the "arginine fingers" of classical GAPs, is flanked by hydrophobic residues. Mutation of Arg15 to methionine abolishes the ability of eIF5 either to stimulate GTP hydrolysis or to support mRNA translation in vitro. Mutation studies suggest that a second conserved arginine (Arg48) also contributes to the GTPase active site of the eIF2.eIF5 complex. Our data thus show that eIF5 behaves as a classical GAP and that GTP hydrolysis during translation involves proteins extrinsic to the ribosome. Indeed, inspection of their sequences suggests that other translation factors may also act as GAPs.

Efficacy and safety of etoricoxib 30 mg and celecoxib 200 mg in the treatment of osteoarthritis in two identically designed, randomized, placebo-controlled, non-inferiority studies

OBJECTIVE

To compare the efficacy of etoricoxib 30 mg with the generally maximum recommended dose of celecoxib, 200 mg, in the treatment of osteoarthritis (OA) in two identically designed studies.

METHODS

Two multi-centre, 26-week, double-blind, placebo-controlled, non-inferiority studies were conducted, enrolling patients who were prior non-steroidal anti-inflammatory drug (NSAID) or acetaminophen users. There were 599 patients in study 1 and 608 patients in study 2 randomized 4:4:1:1 to etoricoxib 30 mg qd, celecoxib 200 mg qd or one of two placebo groups for 12 weeks. After 12 weeks, placebo patients were evenly distributed to etoricoxib or celecoxib based on their initial enrollment randomization schedule. The primary hypothesis was that etoricoxib 30 mg would be at least as effective as celecoxib 200 mg for the time-weighted average change from baseline over 12 weeks for Western Ontario and McMaster (WOMAC) Pain Subscale, WOMAC Physical Function Subscale and Patient Global Assessment of Disease Status. Active treatments were also assessed over the full 26 weeks. Adverse experiences were collected for safety assessment.

RESULTS

In both studies, etoricoxib was non-inferior to celecoxib for all three efficacy outcomes over 12 and 26 weeks; both were superior to placebo (P < 0.001) for all three outcomes in each study over 12 weeks. The safety and tolerability of etoricoxib 30 mg qd and celecoxib 200 mg qd were similar over 12 and 26 weeks.

CONCLUSIONS

Etoricoxib 30 mg qd was at least as effective as celecoxib 200 mg qd and had similar safety in the treatment of knee and hip OA; both were superior to placebo. ClinicalTrials.gov Identifiers: NCT00092768; NCT00092791.

Interleukin-2 and high-dose cisplatin in patients with metastatic melanoma: a pilot study

In this pilot study of metastatic melanoma, interleukin-2 (IL-2) and cisplatin (CDDP) chemotherapy were combined using an alternating schedule designed to explore potential synergism between these modalities. Bolus IL-2 was given at a dose of 600,000 IU/kg intravenously (IV) every 8 hours, days 1 to 5 and 15 to 19, followed by high-dose CDDP administered by two different regimens: (A) 135 to 150 mg/m2 IV bolus over 30 minutes with the chemoprotectant WR-2721 910 mg/m2 or (B) 50 mg/m2 IV over 2 hours every day for 3 days. The trial design allowed an assessment of response to each phase of therapy. Among 27 assessable patients, there were 10 (37%) overall responses, including three (11%) complete responses (CRs) with durations of 9, 16, and 30+ months. Tumor regression was noted in seven patients (partial response [PR], four; minor response [MR], three; response rate [RR], four of 27 [15%]) after IL-2 administration and in 14 patients (PR, 12; MR, two; RR, 12 of 27 [44%]) after CDDP treatment, demonstrating noncrossresistance between the components of the regimen. Major PRs (greater than 90% reduction of tumor burden) or CRs were only seen in patients responding to IL-2. Toxicity during IL-2 therapy was typical for high-dose IL-2 protocols and was reversible. Among the first 20 patients treated with CDDP regimen A, there were eight episodes of grade IV nephrotoxicity (creatinine level greater than 5.0 mg/dL), including three of six patients treated with an initial CDDP dose of 135 mg/m2. This side effect was more frequent among patients with liver metastasis (P less than .05, Fisher's exact test). No significant nephrotoxicity was noted in seven patients treated on regimen B. Although ototoxicity was frequent, minimal bone marrow and neurologic toxicity was noted. There were no treatment-related deaths. This combination showed at least additive activity against melanoma, and the more protracted CDDP schedule was well tolerated. This regimen may serve as a model for future combined immunotherapy and chemotherapy trials in metastatic melanoma.

Analgesic efficacy of paracetamol and diclofenac in children receiving PCA morphine

We studied 80 children, aged 5-13 yr, who received PCA with morphine after appendicectomy using a standardized tracheal general anaesthetic. All patients received morphine 0.1 mg kg-1 before surgical incision and all had wound infiltration with bupivacaine 1 mg kg-1 at the end of surgery. Patients were allocated randomly to receive postoperative analgesia with PCA morphine alone, morphine plus diclofenac 1 mg kg-1, morphine plus paracetamol 15-20 mg kg-1 or morphine plus a combination of both diclofenac and paracetamol. Cumulative morphine consumption was significantly reduced by concurrent administration of diclofenac but no additive effect of paracetamol was demonstrable with the doses used in the study. Analgesia, as assessed by movement pain scoring, was significantly improved by the addition of diclofenac despite lower morphine consumption. Adverse effects and duration of PCA were comparable in the four groups.

Using focus groups to develop health surveys: an example from research on social relationships and AIDS-preventive behavior

Focus group data can inform the choice of words or phrases in a questionnaire, the construction of items to measure a given concept, the formation of new hypotheses, and the development of survey procedures. To date, few examples exist to show researchers in health behavior and health education how they might use focus groups for these purposes. This paper provides an example of group discussions that were held with gay and bisexual men on the topic of their experiences of the human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) epidemic and illustrates the many ways that focus groups assist in questionnaire development.

Solid cancer risk after treatment of Hodgkin's disease

We pooled the data from seven studies of second cancer risk after treatment of Hodgkin's disease (HD) and estimated the relative risks (RR) of solid cancers (SC) for the following two treatment groups: (1) radiotherapy, with or without chemotherapy; and (2) chemotherapy alone. For all treatment groups combined, the RR of SC was 2.1 (95% confidence limits: 1.8 to 2.4). In the radiotherapy group, statistically significant RR were found for SC for all anatomic sites (RR: 2.2; 95% confidence limits: 1.9 to 2.6) and for SC of the bones and joints (RR: 20.0), soft tissues (RR: 18.3), non-HD lymphomas (RR: 8.1), melanomas of the skin (RR: 6.7), buccal cavity and pharynx (RR: 4.1), nervous system (RR: 3.6), respiratory system (RR: 2.5), and digestive system (RR: 1.8). In the chemotherapy alone group, none of the RR differed significantly from unity, and the RR for SC of all sites was 1.1 (95% confidence limits: 0.5 to 1.9). The average duration of follow-up for patients with chemotherapy was shorter than the duration of follow-up for patients with radiotherapy. This may explain the general absence of elevated RR after chemotherapy.

Rate of progression of cognitive decline in Alzheimer's disease: effect of butyrylcholinesterase K gene variation

OBJECTIVE

To determine whether individuals with Alzheimer's disease (AD) and the K variant allele of butyrylcholinesterase have a slower rate of cognitive decline than those without the K variant allele of butyrylcholinesterase.

METHOD

The cognitive status of 339 community based subjects with AD was assessed with the Mini Mental State Examination at baseline and yearly over a three year follow up period. The rates of cognitive decline of subjects with and without the K variant allele were compared.

RESULT

Presence of the K allele was associated with a slower average rate of cognitive decline in subjects with severe AD.

CONCLUSIONS

This finding is consistent with the suggestion that the K variant of butyrylcholinesterase has an important role in disease progression in AD, and this may have implications for treatment.