Inhaled anesthetic responses of recombinant receptors and knockin mice harboring α2(S270H/L277A) GABA(A) receptor subunits that are resistant to isoflurane

The mechanism by which the inhaled anesthetic isoflurane produces amnesia and immobility is not understood. Isoflurane modulates GABA(A) receptors (GABA(A)-Rs) in a manner that makes them plausible targets. We asked whether GABA(A)-R α2 subunits contribute to a site of anesthetic action in vivo. Previous studies demonstrated that Ser270 in the second transmembrane domain is involved in the modulation of GABA(A)-Rs by volatile anesthetics and alcohol, either as a binding site or a critical allosteric residue. We engineered GABA(A)-Rs with two mutations in the α2 subunit, changing Ser270 to His and Leu277 to Ala. Recombinant receptors with these mutations demonstrated normal affinity for GABA, but substantially reduced responses to isoflurane. We then produced mutant (knockin) mice in which this mutated subunit replaced the wild-type α2 subunit. The adult mutant mice were overtly normal, although there was evidence of enhanced neonatal mortality and fear conditioning. Electrophysiological recordings from dentate granule neurons in brain slices confirmed the decreased actions of isoflurane on mutant receptors contributing to inhibitory synaptic currents. The loss of righting reflex EC(50) for isoflurane did not differ between genotypes, but time to regain the righting reflex was increased in N(2) generation knockins. This effect was not observed at the N(4) generation. Isoflurane produced immobility (as measured by tail clamp) and amnesia (as measured by fear conditioning) in both wild-type and mutant mice, and potencies (EC(50)) did not differ between the strains for these actions of isoflurane. Thus, immobility or amnesia does not require isoflurane potentiation of the α2 subunit.

Invasive group A streptococcal infection: an update on the epidemiology and orthopaedic management

Invasive group A streptococcus (iGAS) is the most common cause of monomicrobial necrotising fasciitis. Necrotising infections of the extremities may present directly to orthopaedic surgeons or by reference from another admitting specialty. Recent epidemiological data from the Health Protection Agency suggest an increasing incidence of iGAS infection in England. Almost 40% of those affected had no predisposing illnesses or risk factors, and the proportion of children presenting with infections has risen. These observations have prompted the Chief Medical Officer for the Central Alerting System in England to write to general practitioners and hospitals, highlighting the need for clinical vigilance, early diagnosis and rapid initiation of treatment in suspected cases. The purpose of this annotation is to summarise the recent epidemiological trends, describe the presenting features and outline the current investigations and treatment of this rare but life-threatening condition.

Investigating cognitive deficits and symptomatology across pre-morbid adjustment patterns in first-episode psychosis

BACKGROUND

Cognitive deficits in schizophrenia are well established and are known to be present during the first episode of a psychotic disorder. In addition, consistent heterogeneity within these impairments remains unexplained. One potential source of variability may be the level of pre-morbid adjustment prior to the onset of first-episode psychosis (FEP).

METHOD

Ninety-four FEP patients and 32 healthy controls were assessed at baseline on several neuropsychological tests comprising six cognitive domains (verbal memory, visual memory, working memory, processing speed, reasoning/problem-solving and attention) and an abbreviated version of the full IQ. A global neurocognitive domain was also computed. Pre-morbid adjustment patterns were divided into three distinct groups: stable-poor, stable-good and deteriorating course.

RESULTS

Based on a cut-off of 0.8 for effect size, the stable-poor pre-morbid adjustment group was significantly more impaired on most cognitive domains and full IQ compared to the deteriorating group, who were more severely impaired on all measures compared to the stable-good group. The type of cognitive deficit within each subgroup did not differ and the results indicate that a global neurocognition measure may reliably reflect the severity of cognitive impairment within each subgroup.

CONCLUSIONS

Pre-morbid adjustment patterns prior to onset of psychosis are associated with severity but not type of cognitive impairment. Patients in the stable-poor group are generally more impaired compared to the deteriorating group, who are, in turn, more impaired than the stable-good group.

Methylnaltrexone bromide for the treatment of opioid-induced constipation in patients with advanced illness--a cost-effectiveness analysis

BACKGROUND

Opioid-induced constipation is a common adverse event in patients with advanced illness and has a significant negative impact on patients' quality of life and costs.

AIM

To examine the cost-effectiveness of treating opioid-induced constipation with methylnaltrexone bromide (MNTX) plus standard care compared with standard care alone in patients with advanced illness who receive long-term opioid therapy from a third-party payer perspective in the Netherlands.

METHODS

A decision-analytical model was created in which advanced-illness patients with constipation were treated with MNTX plus standard care or standard care alone. Clinical efficacy in terms of percentage of patients with rescue-free laxation and time to rescue-free laxation were obtained from a randomized, controlled clinical study. Resource use, costs, utilities and mortality were obtained from published literature and supplemented with data from clinical experts.

RESULTS

Treatment with MNTX plus standard care results in more days without constipation symptoms. Cost of MNTX was mostly offset by reduction in other constipation-related costs. Thus, treating with MNTX plus standard care is cost-effective, with an incremental cost per QALY of 40,865 euro. Results were robust to changes in all parameters.

CONCLUSIONS

Although using MNTX may increase total costs, MNTX plus standard care is cost-effective in treating advanced-illness patients with opioid-induced constipation.

A case of necrotising fasciitis caused by Pseudomonas aeruginosa

Necrotising fasciitis is a rare but severe infection of soft-tissue associated with rapid progression, systemic toxicity and high mortality. Monomicrobial necrotising fasciitis caused by Pseudomonas aeruginosa is exceptionally uncommon with only 12 cases reported in the literature. We describe a fatal case with an atypical presentation in a patient following spinal decompression for a metastasis from prostate cancer.

Atomic force microscopy detects differences in the surface brush of normal and cancerous cells

The atomic force microscope is broadly used to study the morphology of cells, but it can also probe the mechanics of cells. It is now known that cancerous cells may have different mechanical properties to those of normal cells, but the reasons for these differences are poorly understood. Here, we report quantitatively the differences between normal and cancerous human cervical epithelial cells by considering the brush layer on the cell surface. These brush layers, which consist mainly of microvilli, microridges and cilia, are important for interactions with the environment. Deformation force curves obtained from cells in vitro were processed according to the 'brush on soft cell model'. We found that normal cells have brushes of one length, whereas cancerous cells have mostly two brush lengths of significantly different densities. The observed differences suggest that brush layers should be taken into account when characterizing the cell surface by mechanical means.

Brain-Targeted Nasal Clonazepam Microspheres

Gelatin-chitosan mucoadhesive microspheres of clonazepam were prepared using the emulsion cross linking method. Mirospheres were evaluated using the in vitro and ex vivo drug release patterns. In vivo CNS drug distribution studies were carried out in rats by administering the clonazepam microspheres intra-nasally and clonazepam solution intravenously. From the drug levels in plasma and CSF, drug targeting index and drug targeting efficiency were calculated. Results obtained indicated that intranasally administered clonazepam microspheres resulted in higher brain levels with a drug targeting index of 2.12. Gelatin-chitosan cross linked mucoadhesive microspheres have the potential to be developed as a brain-targeted drug delivery system for clonazepam.

Prognostic factors of concurrent chemo-radiotherapy in head and neck cancers

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Background: Concurrent chemo-radiotherapy either as primary or adjuvant treatment is now the standard of care in high- risk head and neck squamous cell carcinomas. This has improved survival rates and chances of organ preservation. Advanced stage, extra- capsular extension, perineural and lympho-vascular invasion and positive surgical margins were considered as poor prognostic factors with radiotherapy alone. Herein we report the significance of these clinical and pathological factors, with concurrent chemo-radiotherapy regimens. Methods:A retrospective analysis of 54 patients with squamous cell carcinoma of head and neck who underwent either primary (21,39 %) or adjuvant (33,61%) concurrent chemoradiation at Amrita Institute of Medical Sciences, Kochi, India, during January 2004 to May 2005 and followed up to Dec 2006. 6 (11%) patients had stage III and 48 (89 %) had stage IV disease. Prognostic significance of clinical and pathological factors was evaluated. Kaplan-Meir curves for survival analysis, log rank test for univariate and Cox proportional method for multivariate analysis were employed. Results: The median follow up was 22 months. Two-year overall (OS) and disease free survival (DFS) rates were 66 % and 52 % respectively. Univariate and multivariate analysis of T stage, nodal stage, radiotherapy interruptions, completion of chemotherapy, schedule of chemotherapy (week 1,4,7 vs weekly), perineural invasion, extra-capsular extension and positive margins showed no significant difference in OS and DFS. However both univariate (p = 0.019 for OS and p = 0.012 for DFS) and multivariate analysis (p = 0.029, HR 0.16,95 %CI - 0.03 to 0.8 for OS and p = 0.017,HR 0.188,95% CI - 0.04 to 0.74 for DFS) revealed lympho-vascular invasion as a significant prognostic factor. Conclusions: Advanced stage, extra capsular invasion and positive margins were conventionally thought to be poor prognostic markers in head and neck cancer. However in our series of patients treated with concurrent chemo radiation lymphovascular invasion was the only significant poor prognostic factor. Other factors were found to be not significant.

No significant financial relationships to disclose.

Methicillin-resistant Staphylococcus aureus infection following arthroscopy of the knee joint

Arthroscopic surgery of the knee is considered to be a safe procedure. We had a microbiologically confirmed infection of methicillin-resistant Staphylococcus aureus (MRSA). Although various rare infective cases are reported following arthroscopy of the knee joint, to the best of our knowledge there is no previous report of MRSA infection following arthroscopy of the knee joint.

Vacuum-assisted closure (VAC) therapy in the management of digital pulp defects

Vacuum-assisted closure (VAC) therapy is a relatively new technique in the field of wound management. It has been increasingly used in treating various types of open wounds with effective results and minimal adverse effects. Digital injuries can occasionally be problematic. We report a new application of vacuum-assisted closure therapy in treating digital pulp defects.

Reducing the risk of peripherally inserted central catheter line complications in the oncology setting

At our institution, a retrospective review of peripherally inserted central catheters (PICCs) in oncology patients had previously demonstrated a complication rate of 40.7%. Since then we have implemented strategies to reduce complications including staff and patient education, insertion technique modification and PICC maintenance utilizing a PICC nurse. The objectives of this study were to evaluate the recent PICC complication rate and to compare it with the previously reported findings. Prospectively collected PICC complication data and medical records from all patients with solid tumours who had PICCs inserted in 2003 were analysed. A historical cohort comparative analysis was performed using our PICC complication rate from 2000 to 2001. Eighty-eight PICC lines were inserted in 73 patients under radiological guidance. The median PICC dwell time was 44 days (1-524 days). The overall complication rate was 15.9% (14/88) or 2.0 complications per 1,000 PICC-days. Infections developed in 5.7% (5/88) and thrombotic events occurred in 4.5% (4 /88) of PICCs. The mean time to complication was 45 days. The complication rate for 2003 was significantly lower than the rate for 2001 (P = 0.006), especially of infective complications (P = 0.004). Strategies introduced to reduce PICC complications may have been the reason for this improvement.

Comparison of pioglitazone with other antidiabetic drugs for associated incidence of liver failure: no evidence of increased risk of liver failure with pioglitazone

AIM

The aim of this study was to assess the incidence of liver failure in association with antidiabetic treatment using pioglitazone vs. other oral antidiabetic medications.

METHODS

The study was a retrospective analysis of claim data from the PharMetrics Patient-Centric Database that had over 1.12 million enrollees with type 2 diabetes. All patients, > or =18 years of age with type 2 diabetes, who had initiated treatment either with a thiazolidinedione (pioglitazone and rosiglitazone), sulfonylurea or metformin were identified and matched on the basis of propensity scores, which served as a proxy for severity of disease. The primary measure of interest was the incidence of liver failure or hepatitis post-index date. In addition to unadjusted comparisons, Cox proportional hazard models were employed to estimate the risk of developing liver failure or hepatitis.

RESULTS

There was no significant difference in the 1- and 2-year incidence rates of liver failure or hepatitis (primary and secondary diagnoses) between the pioglitazone monotherapy group and the respective comparator groups. In Cox proportional hazard models controlling for age, pre-index total healthcare costs, Charlson comorbidity index, procedures and a hospitalization or Emergency room (ER) visit for pre-index hyperglycaemia, and pioglitazone were not associated with an increased risk of liver failure or hepatitis, compared to all other defined groups. Furthermore, no primary or secondary diagnosis of liver failure was reported in the pioglitazone group during the follow-up period.

CONCLUSIONS

Results of retrospective data analysis demonstrate no evidence of increased risk of liver failure or hepatitis for patients initiating therapy on pioglitazone, compared to other oral antidiabetic agents. Pioglitazone therapy was not associated with an increased risk of liver failure at 2 years relative to other oral antidiabetic therapies.

Wolcott-Rallison syndrome: a clinical and genetic study of three children, novel mutation in EIF2AK3 and a review of the literature

BACKGROUND

Wolcott-Rallison syndrome is a rare autosomal recessive condition characterized by early infancy onset diabetes mellitus and multiple epiphyseal dysplasia. So far, 17 children have been described in the world literature. Recently, mutations in the gene encoding EIF2AK3 have been shown to segregate with the syndrome in three affected families.

AIMS

We aimed to describe the clinical characterization and mutation analysis of a further child, and full clinical and follow-up details on our first family including the longest surviving child.

METHODS

Retrospective case notes review of three children presenting to the diabetic unit at our institution; mutation analysis of the EIF2AK3 gene in our most recent patient; and review of the literature on Wolcott-Rallison syndrome.

RESULTS

Previously unreported phenotypic features in our patients included developmental regression after episodes of hepatic failure, and pachygyria on brain imaging. We have identified a novel 4-base pair deletion (nt 3021-3024 del GAGA) in exon 13, which results in a frameshift and premature stop codon (R908 F/S +22X), causing premature truncation of the protein and abolition of the carboxy-segment of the catalytic domain.

CONCLUSIONS

Wolcott-Rallison syndrome causes early-onset diabetes and acute hepatic failure, before epiphyseal dysplasia is manifest. We have identified a novel mutation in EIF2AK3, and prenatal diagnosis may now be offered to affected families.

THE RISK OF CHILD AND ADOLESCENT MORTALITY AMONG VULNERABLE POPULATIONS IN RIO DE JANEIRO, BRAZIL

This study investigated the importance of socioeconomic factors such as education, income, religion, family structure and residence in explaining the increased risk of mortality among vulnerable populations aged less than 20 years in Rio de Janeiro, Brazil. Data used were from the 1991 Brazilian Demographic Census and comprised 121,060 women aged 15–49 residing in Rio de Janeiro. Two alternative statistical methods were used to calculate the risk of death: the widely used Brass method (an indirect estimate which assesses population risks) and a case-control study (which assesses individual risks). The study also focused on the importance of indicators of human and social capital, the lack of which may explain the higher risk of death among children and adolescents. Lack of education was found to be a major determinant of mortality at young ages. Residence in a favela (shantytown), families in which mothers were the head of the family, and a lower median level of income were found to be significant determinants of mortality among vulnerable populations in Brazil. However, religion was not found to be as important a predictor of high mortality.