Molecular analysis of isoniazid-resistant Mycobacterium tuberculosis isolates from England and Wales reveals the phylogenetic significance of the ahpC -46A polymorphism

The present study investigated the prevalence and diagnostic potential of the most commonly reported mutations associated with isoniazid resistance, katG 315Thr, katG 315Asn, inhA -15T, inhA -8A, and the oxyR-ahpC intergenic region, in a population sample of 202 isoniazid-resistant Mycobacterium tuberculosis isolates and 176 randomly selected fully sensitive isolates from England and Wales identified by using a directed oligonucleotide array and limited DNA sequencing. The strains were recovered from patients originating from 29 countries; 41 isolates were multidrug resistant. Mutations affecting katG 315, the inhA promoter, and the oxyR-ahpC intergenic region were found in 62.7, 21.9, and 30% of 169 genotypically distinct isoniazid-resistant isolates, respectively, whereas they were found in 0, 0, and 8% of susceptible strains, respectively. The frequency of mutation at each locus was unrelated to the resistance profile or previous antituberculous drug therapy. The commonest mutation in the oxyR-ahpC intergenic region, ahpC -46A, was present in 23.7% of isoniazid-resistant isolates and 7.5% of susceptible isolates. This proved to be a phylogenetic marker for a subgroup of M. tuberculosis strains originating on the Indian subcontinent, which shared IS6110-based restriction fragment length polymorphism and spoligotype features with the Delhi strain and Central Asian strain CAS1; and this marker is strongly associated with isoniazid resistance and the katG 315Thr mutation. In total, 82.8% of unrelated isoniazid-resistant isolates could be identified by analysis of just two loci: katG 315 and the inhA promoter. Analysis of the oxyR-ahpC intergenic region, although phylogenetically interesting, does not contribute significantly to further identification of isoniazid-resistant isolates.

Long-term non-pharmacologic weight loss interventions for adults with type 2 diabetes

BACKGROUND

Most persons with type 2 diabetes are overweight and obesity worsens the metabolic and physiologic abnormalities associated with diabetes.

OBJECTIVES

The objective of this review is to assess the effectiveness of lifestyle and behavioral weight loss and weight control interventions for adults with type 2 diabetes.

SEARCH STRATEGY

Studies were obtained from computerized searches of multiple electronic bibliographic databases, supplemented with hand searches of selected journals and consultation with experts in obesity research. The last search was conducted May, 2004.

SELECTION CRITERIA

Studies were included if they were published or unpublished randomized controlled trials in any language, and examined weight loss or weight control strategies using one or more dietary, physical activity, or behavioral interventions, with a follow-up interval of at least 12 months.

DATA COLLECTION AND ANALYSIS

Effects were combined using a random effects model.

MAIN RESULTS

The 22 studies of weight loss interventions identified had a 4,659 participants and follow-up of 1 to 5 years. The pooled weight loss for any intervention in comparison to usual care among 585 subjects was 1.7 kg (95 % confidence interval [CI] 0.3 to 3.2), or 3.1% of baseline body weight among 517 subjects. Other main comparisons demonstrated nonsignificant results: among 126 persons receiving a physical activity and behavioral intervention, those who also received a very low calorie diet lost 3.0 kg (95% CI -0.5 to 6.4), or 1.6% of baseline body weight, more than persons receiving a low-calorie diet. Among 53 persons receiving identical dietary and behavioral interventions, those receiving more intense physical activity interventions lost 3.9 kg (95% CI -1.9 to 9.7), or 3.6% of baseline body weight, more than those receiving a less intense or no physical activity intervention. Comparison groups often achieved significant weight loss (up to 10.0 kg), minimizing between-group differences. Changes in glycated hemoglobin generally corresponded to changes in weight and were not significant when between-group differences were examined. No data were identified on quality of life and mortality.

AUTHORS' CONCLUSIONS

Weight loss strategies using dietary, physical activity, or behavioral interventions produced small between-group improvements in weight. These results were minimized by weight loss in the comparison group, however, and examination of individual study arms revealed that multicomponent interventions including very low calorie diets or low calorie diets may hold promise for achieving weight loss in adults with type 2 diabetes.

[Mutations linked with antimicrobial resistance in Mycobacterium tuberculosis isolated from tuberculosis patients in the Samara region]

A total of 234 M. tuberculosis isolates were used to demonstrate the leading role of mutations in, respectively, codon 531 of gene rpoB (90.0%) and codon 315 of gene katG (92.9%), in the development of resistance to rifampicin and isoniazid by the methods of reverse hybridization with oligonucleotide probes and the sequencing of gene stretches. The levels of primary resistance of M. tuberculosis to rifampicin, isoniazid and multiresistance, according to the molecular-genetic analysis, were 41.0%, 57.7% and 37.2% respectively. The coincidence of the results of the bacteriological and molecular-genetic analyses of the antimicrobial resistance of the isolates was 90.4% and 95.3% for isoniazid and rifampicin respectively. The prevalence of individual types of mutations, linked with antimicrobial resistance, in the presence of a considerable spread of strains of the family Beijing in the region may be indicative of the limited number of M. tuberculosis clones circulating in the region.

What are the long-term benefits of weight reducing diets in adults? A systematic review of randomized controlled trials

BACKGROUND

Evidence is needed for the best long-term diet for weight loss, and improvement in cardiac risk and disease in obese adults.

METHODS

We systematically reviewed randomized controlled trials (RCTs) in any language. We searched 13 databases and handsearched journals. Trials lasted 1 year or more. One investigator extracted the data and a second checked data extraction. Trial quality was assessed.

RESULTS

Low fat diets (LFDs) produced significant weight losses up to 36 months (-3.55 kg; 95% CI, -4.54 to -2.55 kg). Blood pressure, lipids and fasting plasma glucose improved with these diets after 12 months. Four studies found that LFDs may prevent type 2 diabetes and reduce antihypertensive medication for up to 3 years. A very low calorie diet (VLCD, < 4.2 MJ day(-1)) was associated with the most weight loss after 12 months (-13.40 kg; 95% CI, -18.43 to -8.37 kg) in one small study with beneficial effects on asthma. There was no evidence that low carbohydrate protein sparing modified fasts (PSMFs) were associated with greater long-term weight loss than low calorie diets (LCDs, 4.2-6.7 MJ day(-1)) or VLCDs. PSMFs were, however, associated with greater lowering of fasting plasma glucose and HbA1c than LCDs.

CONCLUSIONS

Little evidence supports the use of diets other than LFDs for weight reduction. With the increasing prevalence of morbid obesity, long-term follow-up in RCTs is needed to evaluate the effect of LCDs, VLCDs and PSMFs more fully.

Systematic review of the long-term effects and economic consequences of treatments for obesity and implications for health improvement

OBJECTIVES

To undertake a systematic review of the long-term effects of obesity treatments on body weight, risk factors for disease, and disease.

METHODS

The study encompassed three systematic reviews that examined different aspects of obesity treatments. (1) A systematic review of obesity treatments in adults where the methods of the Cochrane Collaboration were applied and randomised controlled trials (RCTs) with a follow-up of at least 1 year were evaluated. (2) A systematic epidemiological review, where studies were sought on long-term effects of weight loss on morbidity and/or mortality, and examined through epidemiological modelling. (3) A systematic economic review that sought reports with both costs and outcomes of treatment, including recent reports that assessed the cost-effectiveness of pharmaceutical and surgical interventions. A Markov model was also adopted to examine the cost-effectiveness of a low-fat diet and exercise intervention in adults with obesity and impaired glucose tolerance.

RESULTS

The addition of the drugs orlistat or sibutramine was associated with weight loss and generally improved risk factors, apart from diastolic blood pressure for sibutramine. Metformin was associated with decreased mortality after 10 years in obese people with type 2 diabetes. Low-fat diets were associated with continuing weight loss for 3 years and improvements in risk factors, as well as prevention of type 2 diabetes and improved control of hypertension. Insufficient evidence was available to demonstrate the benefits of low calorie or very low calorie diets. The addition of an exercise or behaviour programme to diet was associated with improved weight loss and risk factors for at least 1 year. Studies combining low-fat diets, exercise and behaviour therapy suggested improved hypertension and cardiovascular disease. Family therapy was associated with improved weight loss for 2 years compared to individual therapy. There was insufficient evidence to conclude that individual therapy was more beneficial than group therapy. Weight lost more quickly (within 1 year), from the epidemiology review, may be more beneficial with respect to the risk of mortality. The effects of intentional weight loss need further investigation. Weight loss from surgical and non-surgical interventions for people suffering from obesity was associated with decreased risk of development of diabetes, and a reduction in low-density lipoprotein cholesterol, total cholesterol and blood pressure, in the long term. Targeting high-risk individuals with drugs or surgery was likely to result in a cost per additional life-year or quality-adjusted life-year (QALY) of no more than 13,000 British pounds. There was also suggestive evidence of cost saving from treatment of people with type 2 diabetes with metformin. Targeting surgery on people with severe obesity and impaired glucose tolerance was likely to be more cost-effective at 2329 British pounds per additional life-year. Economic modelling over 6 years for diet and exercise for people with impaired glucose tolerance was associated with a high initial cost per additional QALY, but by the sixth year the cost per QALY was 13,389 British pounds. Results did not include cost savings from diseases other than diabetes, and therefore may be conservative.

CONCLUSIONS

The drugs orlistat and sibutramine appear beneficial for the treatment of adults with obesity, and metformin for obese patients with type 2 diabetes. Exercise and/or behaviour therapy appear to improve weight loss when added to diet. Low-fat diets with exercise, or with exercise and behaviour therapy are associated with the prevention of type 2 diabetes and hypertension. Long-term weight loss in epidemiological studies was associated with reduced risk of type 2 diabetes, and may be beneficial for cardiovascular disease. Low-fat diets and exercise interventions in individuals at risk of obesity-related illness are of comparable cost to drug treatments. Long-term pragmatic RCTs of obesity treatments in populations with obesity-related illness or at high risk of developing such illness are needed (to include an evaluation of risk factors, morbidity, quality of life and economic evaluations). Drug trials that include dietary advice, plus exercise and/or behaviour therapy are also needed. Research exploring effective types of exercise, diet or behaviour and also interventions to prevent obesity in adults is required.

What interventions should we add to weight reducing diets in adults with obesity? A systematic review of randomized controlled trials of adding drug therapy, exercise, behaviour therapy or combinations of these interventions

BACKGROUND

Evidence is needed for the effectiveness of interventions given with reducing diets for obese adults: drug therapy, exercise, or behaviour therapy.

METHODS

We systematically reviewed randomized controlled trials in any language. We searched 13 databases and handsearched journals. Trials lasted 1 year or more. One investigator extracted data and a second checked data extraction. Trial quality was assessed.

RESULTS

Adding orlistat to diet was associated with weight change for up to 24 months (-3.26 kg, 95% CI, -4.15 to -2.37 kg), and statistically significant beneficial changes were found for total and LDL cholesterol, blood pressure and glycaemic control. Adding sibutramine to diet was associated with a 12 month weight change of -4.18 kg (95% CI, -5.14 to -3.21 kg), and statistically significant beneficial effects on high density lipoprotein cholesterol (HDL) and triglycerides (TGs), but an increase in diastolic blood pressure. Adding exercise to diet, or to diet and behaviour therapy, was associated with improved weight loss for up to 36 months and improvements in HDL, TGs and blood pressure. Adding behaviour therapy to diet, or to diet and sibutramine together, was associated with improved weight loss for up to 18 months. Adding drugs, exercise or behaviour therapy to dietary advice was each associated with similar weight change.

CONCLUSIONS

Adding orlistat, sibutramine, exercise, or behaviour modification to dietary advice can improve long-term weight loss.

Androgen induced acceleration of functional recovery after rat sciatic nerve injury

PURPOSE: Testosterone (T) treatment accelerates recovery from facial paralysis after facial nerve crush in hamsters. In this study, we extended those studies to another injury model and asked the following question: Will T treatment accelerate recovery from lower limb paralysis following sciatic nerve crush in the rat? METHODS: Castrated adult male rats received a right side sciatic nerve crush at the level of the sciatic notch, with the left side serving as control. Half the animals received a subcutaneous implant of a propionated form of T (TP), the others were sham-implanted. Weekly testing using the Sciatic Functional Index (SFI), a quantitative measure of locomotion, was done for 7 weeks postoperative (wpo). RESULTS: Between 3 and 5 weeks post-op, the average SFI score of the TP-treated group was higher than controls. This difference was significant at 4 wpo, indicating an accelerated degree of functional recovery. At these timepoints, the differences were attributable to the footprint or paw length and associated with calf muscle reinnervation rather than the toespreading component associated with intrinsic foot muscle rein-nervation. Beyond 5 wpo, there were no differences in the SFI scores. CONCLUSION: The results indicate that, as with facial nerve regeneration in the hamster, testosterone accelerates functional recovery from hind limb paralysis following sciatic nerve injury in the rat. While the responses of spinal motoneurons to injury can differ from those of cranial motoneurons, in this case it appears that they share a similar response to the trophic actions of androgen. This is important in the context of designing therapeutic strategies for dealing with direct trauma to motoneurons resulting from both peripheral and central nervous system trauma, such as spinal cord injury.

Use of a cell line to investigate olfactory ensheathing cell-enhanced axonal regeneration

Olfactory ensheathing cells (OECs), a unique type of macroglia required for normal olfactory axonal regeneration throughout the lifetime of an individual, have been shown to have regeneration-enhancing properties when used to treat various neuronal injuries. Availability of OECs is a hurdle facing future clinical use of the cells for spinal cord injury (SCI) therapy. The number of OECs that can realistically be harvested from each animal is limited, and ensuring a pure cell population is difficult. We have begun to characterize a nonsyngeneic strain of OECs, i.e., from a homogenous OEC clonal cell line (nOECs). The purpose of this study was to determine whether nOECs have the same properties and provide the same functional recovery after SCI, as primary cultures of OECs. The results indicate that nOECs survive in vivo, produce growth-promoting proteins, and possess regeneration-promoting capabilities. Spinal cord injured rats that were treated with nOECs performed significantly better on functional tests than injured control animals beginning at 5 weeks after operation. In summary, evidence of nOEC regeneration-promoting capabilities suggests that this cell line can be used as potential therapy in SCI research.

Motion analysis

BACKGROUND

The ability to make an objective evaluation of a surgeon's operative ability remains an elusive goal. In this study, we used motion analysis as a measure of dexterity in the performance of a simulated operation.

METHODS

Fifteen surgeons performed a total of 45 laboratory-based laparoscopic cholecystectomies on a cadaveric porcine liver model. Subjects were assigned to one of three groups according to their level of experience in human laparoscopic cholecystectomy. Electromagnetic tracking devices were used to analyze the surgeon's hand movements as they performed the procedure. Movement data (time, distance, number of movements, and speed of movement) were then compared.

RESULTS

Analysis of variance (ANOVA) movement scores across the three groups showed significantly better performance among the experienced laparoscopic surgeons than the novices. Learning curves across repetitions of procedures were plotted. Novices made more improvement than experts.

CONCLUSIONS

Motion analysis provides useful data for the assessment of laparoscopic dexterity, and the porcine liver model is a valid simulation of the real procedure.

Androgenic enhancement of betaII-tubulin mRNA in spinal motoneurons following sciatic nerve injury

PURPOSE

We have previously demonstrated that systemic administration of testosterone propionate (TP) can accelerate the functional recovery from hind limb paralysis following sciatic nerve injury in the rat. In this study, we looked at the molecular mechanisms underlying this phenomenon.

METHODS

Castrated adult male rats received a right side sciatic nerve crush at the level of the sciatic notch, with the left side serving as control. Half the animals received a subcutaneous implant of TP, the others were sham implanted. Animals were sacrificed at 1, 3, 7 and 10 days post-operative. Lumbar spinal cord tissue was harvested and in situ hybridization was performed using a cytoskeletal cDNA probe complementary to betaII-tubulin.

RESULTS

On the injured side, sciatic motoneuron tubulin mRNA levels were increased in alt groups at alt time points. At 3 and 7 days post- op, the TP treated group had significantly higher levels of tubulin mRNA.

CONCLUSIONS

These results suggest that testosterone enhances the rate of regeneration by increasing the neuronal cytoskeletal response after axonal injury. Further, these results, coupled with the results from previous experiments in other rodent models, suggest a common mechanism for gonadal steroid action on regenerating motoneurons across species.

Neuroprotective effects of gonadal steroids on regenerating peripheral motoneurons

In this review, the neuroprotective actions of testosterone on three different populations of injured rat peripheral motoneurons, i.e. facial (FMN), spinal (SMN) and pudendal (PMN), will be discussed. We have extrapolated concepts from the neuroendocrine field regarding the trophic effects of gonadal steroids on target neural tissue to the nerve regeneration field. Exogenous administration of testosterone immediately after nerve injury impacts positively on functional recovery through actions mediated by the androgen receptor. The mechanism by which steroidal enhancement of the regenerative properties of injured motoneurons occurs may involve pre-existing androgen receptors, heat shock proteins, and modulation of the cellular stress response.

Rifampin resistance in Mycobacterium kansasii is associated with rpoB mutations

Rifampin is the most potent drug used in the treatment of disease due to Mycobacterium kansasii. A 69-bp fragment of rpoB, the gene that encodes the beta subunit of the bacterial RNA polymerase, was sequenced and found to be identical in five rifampin-susceptible clinical isolates of M. kansasii. This sequence showed 87% homology with the Mycobacterium tuberculosis gene, with an identical deduced amino acid sequence. In contrast, missense mutations were detected in the same fragment amplified from five rifampin-resistant isolates. A rifampin-resistant strain generated in vitro also harbored an rpoB gene missense mutation that was not present in the parent isolate. All mutations detected (in codons 513, 526, and 531) have previously been described in rifampin-resistant M. tuberculosis isolates. Rifampin MICs determined by E-test were <1 mg/liter for all rifampin-susceptible isolates and >256 mg/liter for all rifampin-resistant ones. In addition, four of the five rifampin-resistant isolates were also resistant to rifabutin. We have thus shown a strong association between rpoB gene missense mutations and rifampin resistance in M. kansasii. Although our results are derived from a small number of isolates and confirmation with larger numbers would be useful, they strongly suggest that mutations within rpoB form the molecular basis of rifampin resistance in this species.

CD8 T lymphocytes and macrophages infiltrate coronary artery aneurysms in acute Kawasaki disease

The pathogenesis of coronary arterial inflammation in acute Kawasaki disease (KD) is unclear. To test the hypothesis that the KD vascular lesion is an activated T lymphocyte-dependent process, immunohistochemical studies were done on coronary artery aneurysms from 8 fatal acute KD cases by using antibodies to CD45RO (activated or memory T lymphocyte), CD8 (cytotoxic T lymphocyte), CD4 (helper T lymphocyte), HAM56 (macrophage), and CD20 (B lymphocyte). Acute KD coronary arteritis was characterized by transmural infiltration of CD45RO T lymphocytes with CD8 T lymphocytes predominating over CD4 T lymphocytes. Macrophages were present primarily in the adventitial layer; B lymphocytes were notably absent. These data lend support to the hypotheses that KD results from infection with an intracellular pathogen, such as a virus, whose antigens are presented by major histocompatibility complex class I molecules, and that CD8 T lymphocytes and macrophages are important in the pathogenesis of KD coronary aneurysms.

New Glucocorticosteroids with an improved therapeutic ratio?

Glucocorticoids (GCs) remain the most effective therapy for inflammatory disorders. In terms of asthma, topical steroids are the mainstay for controlling the inflammatory component of the disease. However, their use is limited by the constellation of adverse effects associated with chronic, oral steroid use and the long-term adverse effects associated with inhaled steroid use. These include suppression of hypothalamic--pituitary axis, osteoporosis, reduced bone growth in the young, opportunistic infections, behavioural alterations, and disorders of lipid metabolism. Most of these effects may be attributable to the endocrine activity of steroids and are largely identical to the syndromes of endogenous corticosteroid excess (Cushing's Syndrome). Thus, the Holy Grail of steroid pharmacology is the development of agents which have a markedly improved therapeutic ratio than current steroids, especially on systemic administration. This may be achieved by the identification of molecules which elicit marked antiinflammatory effects, but have a minor impact on endocrine responses. Dissociated corticosteroids are ligands for the glucocorticoid receptor that may offer the potential for a more selective antiinflammatory profile.

Glucagon-like peptide (GLP)-2 action in the murine central nervous system is enhanced by elimination of GLP-1 receptor signaling

Glucagon-like peptide-2 (GLP-2) regulates energy homeostasis via effects on nutrient absorption and maintenance of gut mucosal epithelial integrity. The biological actions of GLP-2 in the central nervous system (CNS) remain poorly understood. We studied the sites of endogenous GLP-2 receptor (GLP-2R) expression, the localization of transgenic LacZ expression under the control of the mouse GLP-2R promoter, and the actions of GLP-2 in the murine CNS. GLP-2R expression was detected in multiple extrahypothalamic regions of the mouse and rat CNS, including cell groups in the cerebellum, medulla, amygdala, hippocampus, dentate gyrus, pons, cerebral cortex, and pituitary. A 1.5-kilobase fragment of the mouse GLP-2R promoter directed LacZ expression to the gastrointestinal tract and CNS regions in the mouse that exhibited endogenous GLP-2R expression, including the cerebellum, amygdala, hippocampus, and dentate gyrus. Intracerebroventricular injection of GLP-2 significantly inhibited food intake during dark-phase feeding in wild-type mice. Disruption of glucagon-like peptide-1 receptor (GLP-1R) signaling with the antagonist exendin-(9-39) in wild-type mice or genetically in GLP-1R(-)/- mice significantly potentiated the anorectic actions of GLP-2. These findings illustrate that CNS GLP-2R expression is not restricted to hypothalamic nuclei and demonstrate that the anorectic effects of GLP-2 are transient and modulated by the presence or absence of GLP-1R signaling in vivo.

Perineural invasion of cutaneous malignancies

BACKGROUND

Perineural invasion is an important mode of tumor spread and is associated with increased aggressiveness and a propensity for recurrence among cutaneous malignancies.

OBJECTIVE

To review the pathogenesis, diagnosis, and treatment of cutaneous tumors exhibiting perineural invasion.

METHODS

This article is based on a review of the medical literature concerning tumors with perineural involvement.

RESULTS

This article describes the clinical signs and histologic features of cutaneous malignancies exhibiting perineural involvement.

CONCLUSION

Appropriate patient care mandates consideration of perineural invasion in the evaluation of cutaneous tumors. As the majority of patients present without symptoms of neural involvement, physicians must be vigilant in the search for this type of tumor spread.

Loss of androgen receptor associated protein 70 (ARA70) expression in a subset of HER2-positive breast cancers

Co-transfection studies indicate that HER2 (erbB-2) overexpression results in the phosphorylation and enhanced transcriptional activity of the androgen receptor (AR). This amplification of AR action is further enhanced by the expression of ARA70, a putative co-activator with a predilection for the AR. Because androgens inhibit the growth of breast cancer cells whereas HER2 overexpression stimulates the growth of these cells, it seems possible that loss of expression of AR or ARA70 in some HER2 overexpressing tumors might confer a growth advantage to these cells. We examined ARA70 and AR expression in 20 HER2-positive (overexpressing) and 21 HER2-negative cases of breast invasive ductal carcinoma (IDC) to determine the relationship between loss of ARA70 and/or AR with HER2 overexpression. Strong ARA70 immunostaining was observed in all normal and breast epithelial cells in fibrocystic change and in in situ carcinoma present in the patient samples. Of the 41 cases of IDC, focal or complete loss of ARA70 protein expression was observed in 46% of the cases, with 60% of HER2-positive versus 33% of HER2-negative cases showing loss. Loss of AR expression was observed in 60% of HER2-positive versus 43% of HER2-negative cases. Remarkably, only 20% of HER2-positive tumors expressed both AR and ARA70, while 43% of HER2-negative tumors expressed both of these elements of the AR signaling pathway. This trend is consistent with a possible clinical relevance of the potential crosstalk between the HER2 and AR signaling pathways. Western blot analysis for ARA70 expression performed on frozen breast biopsies of normal or malignant breast tissue from four patients revealed a 70 kDa immunoreactive band in all four normal tissue samples, with an additional 35 kDa band in two of the breast cancer samples and in human breast cancer MCF-7 cells. This may reflect aberrant splicing in some breast cancers, leading to the emergence of the 35 kDa isoform.

DNA array technology and diagnostic microbiology

Near instantaneous detection of pathogens from clinical material, combined with simultaneous prediction of their antimicrobial resistance profiles, would revolutionize the impact of microbiology on the management of infection. Array-based assays allow a range of characteristics to be rapidly and simultaneously determined. At present these systems have found their primary role as research tools for the monitoring of mRNA expression in the form of DNA microarrays or 'chips'. As fabrication costs reduce and validated targeted arrays are developed, it is inevitable they will be used for more routine applications. Microfluidics offers the exciting possibility of combining purification, amplification and detection in a single disposable device; microarrays are particularly suitable for use within these systems. Arrays will become an important tool for clinical diagnostics.

Therapeutic benefit of a dissociated glucocorticoid and the relevance of in vitro separation of transrepression from transactivation activity

Glucocorticoids (GCs) are the mainstay of asthma therapy; however, major side effects limit their therapeutic use. GCs influence the expression of genes either by transactivation or transrepression. The antiinflammatory effects of steroids are thought to be due to transrepression and the side effects, transactivation. Recently, a compound, RU 24858, has been identified that demonstrated dissociation between transactivation and transrepression in vitro. RU 24858 exerts strong AP-1 inhibition (transrepression), but little or no transactivation. We investigated whether this improved in vitro profile results in the maintenance of antiinflammatory activity (evaluated in the Sephadex model of lung edema) with reduced systemic toxicity (evaluated by loss in body weight, thymus involution, and bone turnover) compared with standard GCs. RU 24858 exhibits comparable antiinflammatory activity to the standard steroid, budesonide. However, the systemic changes observed indicate that transactivation events do occur with this GC with similar potency to the standard steroids. In addition, the GCs profiled showed no differentiation on quantitative osteopenia of the femur. These results suggest that in vitro separation of transrepression from transactivation activity does not translate to an increased therapeutic ratio for GCs in vivo or that adverse effects are a consequence of transrepression.

Activation of androgen receptor-associated protein 70 (ARA70) mRNA expression in ovarian cancer

OBJECTIVE

Androgens have been implicated in ovarian cancer and androgen receptor expression has been reported in 70-95% of ovarian adenocarcinomas, implying a role in ovarian cancer cell biology. Androgen receptor-associated protein 70 (ARA70) is a reported androgen receptor coactivator that enhances the transactivational potential of the androgen receptor up to 10-fold. Because ARA70 expression could amplify androgen action in ovarian cancer cells, we examined patient samples of ovarian cancer for ARA70 expression.

METHODS

Twenty invasive ovarian carcinomas and four nonmalignant ovaries were tested for ARA70 mRNA expression by in situ hybridization using a 35S-labeled riboprobe.

RESULTS

The probe was first assessed using a sample of human benign prostatic hyperplasia. Expression was restricted to cells within the epithelial glands, which are known to express the highest levels of androgen receptor. In the nonmalignant ovary, ARA70 mRNA was expressed in moderate levels in thecal cells associated with antral follicles, with less labeling observed in granulosa cells and stroma. The surface epithelium was negative for ARA70 transcripts, with only low levels observed in occasional cells. In contrast, a high level of ARA70 expression was observed in 17 of the 20 ovarian carcinomas of various histological types. Labeling was associated with the tumor cells while little if any ARA70 mRNA was observed in stromal cells associated with the carcinoma.

CONCLUSION

These observations indicate that ARA70 expression is activated in invasive ovarian cancer tumor cells, and suggest that amplification of androgen action by ARA70 may be involved in the etiology/progression of this disease.

Antiviral agents

The potential severity of many viral infections and the lack of appropriate treatment for these diseases have been a source of endless frustration and helplessness for clinicians. The newly developed field of antiviral therapy is expanding at an astounding rate, with new discoveries each day. Although physicians are not yet able to cure many of the viral infections, such as HSV, HIV, and CMV, a means of controlling them is available. It is hoped that the research and investigations currently under way will lead to a future era of antiviral drugs that will be able to eradicate these diseases.

Studies of isopenicillin N synthase enzymatic properties using a continuous spectrophotometric assay

Isopenicillin N synthase (IPNS) from Aspergillus nidulans is a no-heme iron(II)-dependent oxygenase which catalyses, in a single reaction, the bicyclisation of delta-(L-alpha-aminoadipoyl)-L-cysteinyl-D-valine into isopenicillin N, the precursor of all other penicillins, cephalosporins and cephamycins. The IPNS reaction can be followed directly and continuously by a new assay which monitors the absorbance increase at 235 nm characteristic of penicillin nucleus formation. Using this assay, the effects of influential factors affecting the in vitro IPNS enzymatic reaction were investigated. Even under optimal conditions, enzyme inactivation occurred during catalysis. Iron(II) depletion and product inhibition were not the cause of this phenomenon, the addition of antioxidants or reducing agents failed to slow down inactivation or reactivate the enzyme. Therefore, this phenomenon appears to be irreversible and is attributed to oxidative damage caused to the enzyme by reactive oxygen species generated in solution during catalysis. Nevertheless, the steady-state kinetic parameters for the IPNS reaction were determined.

Biosynthesis of glycosaminoglycans and proteoglycans by the lymph node

Previous studies of hyaluronan uptake and catabolism by lymph nodes indicated that the nodes might also add some HA of low molecular weight to the unabsorbed fraction that passes through from afferent to efferent lymph vessels. The ability of lymph nodes to synthesise HA and proteoglycans was therefore examined (i) by perfusion of [(3)H] acetate through an afferent lymph vessel in vivo, and recovery of labeled products from the efferent lymph vessel and from the node after perfusion; and (ii) by tissue culture of lymph nodes with [(3)H] acetate. Perfusion of lymph nodes with [(3)H] acetate in situ yielded: (a), in outflowing lymph, small amounts of chondroitin/dermatan sulfate within the first hour which continued to be produced for up to 24 h; heparin in the second hour and HA in the third. In the nodes removed 17 to 19 h later, equal amounts of hyaluronan and chondroitin/dermatan sulfate and heparan sulfate proteoglycans were detected. In the tissue culture of lymph nodes: (1) HA, heparin and proteoglycans of heparan sulfate and chondroitin/dermatan sulfate were released into the medium but in the cell extract only heparan sulfate proteoglycan was detected; and (ii) molecular weight of the released hyaluronan ranged widely but was mostly less than 4-5x10(5)D; heparan sulfate proteoglycan was 2.8x10(4) to 9.4x10(5)D; heparin 7.9x10(4)D and chondroitin sulfate 1.3x10(4)D, suggesting that the chondrotin sulfate were released from their proteoglycans core by enzymic degradation. It is concluded that lymph nodes can release HA, heparin, heparan sulfate and chondroitin/dermatan sulfate proteoglycans into efferent lymph but the amount of hyaluronan is likely to be small without immune or other stimulation and its molecular weight is lower than in other tissues.

The addition of low numbers of 3' thymine bases can be used to improve the hybridization signal of oligonucleotides for use within arrays on nylon supports

Oligonucleotide arrays can be used for the analysis of microbial nucleic acid. The addition of high numbers of dTTP to the 3' ends of oligonucleotides using terminal transferase has been shown to facilitate membrane binding. This paper demonstrates low numbers of thymine bases added to the 3' end of oligonucleotides during synthesis can improve hybridisation signal intensity where the signal seen with the unmodified oligonucleotides is poor. Thus, the addition of variable numbers of thymine bases to different oligonucleotides allows the production of oligonucleotide arrays producing strong interpretable hybridisation signals.