Prevention of recurrence and prolonged survival in primary central nervous system lymphoma (PCNSL) patients treated with adjuvant high-dose methylprednisolone

Five patients at risk for primary central nervous system lymphoma (PCNSL) recurrence were treated with high-dose methylprednisolone, (HDMP) to prevent ‘trafficking’ of malignant lymphocytes into the central nervous system (CNS). HDMP was chosen because of its ability to stabilize the ‘blood brain barrier (BBB)’. Three men with newly diagnosed PCNSL, ages 62, 76 and 78 y, whose survival was projected to be 6.6 months, began treatment after achieving complete response (CR) to initial radiation therapy alone and survived 27, 37 and 59 months after treatment. In none was death from recurrent disease in CNS but one patient did die of systemic non-Hodgkin’s lymphoma (NHL) five years after PCNSL diagnosis. A 20 y old man was treated with HDMP after successful combined modality therapy and is alive 75+months after initial diagnosis without evidence of disease recurrence. A 34 y old man relapsed after combined modality initial treatment and failed to respond to HDMP when treatment was begun after unsuccessful salvage therapy; he died of disease 12 months after initial diagnosis. There were no treatment complications. The promising results in this pilot study from the basis for a North Central Cancer Treatment Group (NCCTG) 96-73-51, a Phase 2 clinical trial of brain radiotherapy and HDMP for PCNSL patients 70 y of age and older, a group of patients at high risk for toxicity from intensive combined modality therapy.     

CFTR mediated chloride secretion in the avian renal proximal tubule

In primary cell cultures of the avian (Gallus gallus) renal proximal tubule parathyroid hormone and cAMP activation generate a Cl⁻-dependent short circuit current (I_SC) response, consistent with net transepithelial Cl⁻ secretion. In this study we investigated the expression and physiological function of the Na-K-2Cl (NKCC) transporter and CFTR chloride channel, both associated with Cl⁻ secretion in a variety of tissues, in these proximal tubule cells. Using both RT-PCR and immunoblotting approaches, we showed that NKCC and CFTR are expressed, both in proximal tubule primary cultures and in a proximal tubule fraction of non-cultured (native tissue) fragments. We also used electrophysiological methods to assess the functional contribution of NKCC and CFTR to forskolin-activated I_SC responses in filter grown cultured monolayers. Bumetanide (10 μM), a specific blocker of NKCC, inhibited forskolin activated I_SC by about 40%, suggesting that basolateral uptake of Cl⁻ is partially mediated by NKCC transport. In monolayers permeabilized on the basolateral side with nystatin, forskolin activated an apical Cl⁻ conductance, manifested as bidirectional diffusion currents in the presence of oppositely directed Cl⁻ gradients. Under these conditions the apical conductance appeared to show some bias towards apical-to-basolateral Cl⁻ current. Two selective CFTR blockers, CFTR Inhibitor 172 and GlyH-101 (both at 20 μM) inhibited the forskolin activated diffusion currents by 38-68%, with GlyH-101 having a greater effect. These data support the conclusion that avian renal proximal tubules utilize an apical CFTR Cl⁻ channel to mediate cAMP-activated Cl⁻ secretion.     

Clonidine fails to reduce pressor responsiveness of conscious spontaneously hypertensive rats to vasopressin

Pressor responses and heart rate responses to intravenous injections (3.5-50.0 pmol/kg) of arginine vasopressin (AVP) were recorded in saline- and clonidine-treated spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats. Clonidine (20 micrograms/kg, i.v.) caused a marked fall of arterial pressure in SHR but not in WKY rats so that, 20 min after the injection of the alpha 2-adrenoceptor agonist, arterial pressure was similar in the two strains of rats. The curve expressing the relationship between the dose of AVP and the increase of arterial pressure for saline-treated SHR was positioned to the left of that for saline-treated WKY rats. This enhanced pressor responsiveness of SHR to AVP may have been related to impaired reflex activity since heart rate fell much less in SHR than in WKY rats for a given elevation in pressure. Pressure responses to AVP were augmented by clonidine in both SHR and WKY rats so that, similar to saline-treated rats, pressor responsiveness to the peptide was still greater in SHR. Heart rate responses to AVP were not altered significantly by clonidine. The results indicate that clonidine fails to enhance reflex activity and reduce pressor responsiveness of SHR to AVP. The increased pressor responsiveness of both SHR and WKY rats to AVP following clonidine was an unexpected finding and may be related to a peripheral interaction between alpha-adrenergic agonists and AVP.     

Identification of broadly neutralizing antibody epitopes in the HIV-1 envelope glycoprotein using evolutionary models

Background

Identification of the epitopes targeted by antibodies that can neutralize diverse HIV-1 strains can provide important clues for the design of a preventative vaccine.

Methods

We have developed a computational approach that can identify key amino acids within the HIV-1 envelope glycoprotein that influence sensitivity to broadly cross-neutralizing antibodies. Given a sequence alignment and neutralization titers for a panel of viruses, the method works by fitting a phylogenetic model that allows the amino acid frequencies at each site to depend on neutralization sensitivities. Sites at which viral evolution influences neutralization sensitivity were identified using Bayes factors (BFs) to compare the fit of this model to that of a null model in which sequences evolved independently of antibody sensitivity. Conformational epitopes were identified with a Metropolis algorithm that searched for a cluster of sites with large Bayes factors on the tertiary structure of the viral envelope.

Results

We applied our method to ID₅₀ neutralization data generated from seven HIV-1 subtype C serum samples with neutralization breadth that had been tested against a multi-clade panel of 225 pseudoviruses for which envelope sequences were also available. For each sample, between two and four sites were identified that were strongly associated with neutralization sensitivity (2ln(BF)?>?6), a subset of which were experimentally confirmed using site-directed mutagenesis.

Conclusions

Our results provide strong support for the use of evolutionary models applied to cross-sectional viral neutralization data to identify the epitopes of serum antibodies that confer neutralization breadth.

     

Rising Obesity-Related Hospital Admissions among Children and Young People in England: National Time Trends Study

Objective

To describe the trends in hospital admissions associated with obesity as a primary diagnosis and comorbidity, and bariatric surgery procedures among children and young people in England.

Design

National time trends study of hospital admissions data between 2000 and 2009.

Participants

Children and young people aged 5 to 19 years who were admitted to hospital with any diagnosis of obesity.

Main outcome measures

Age- and sex-specific admission rates per million children.

Results

Between 2000 and 2009, age- and sex-specific hospital admission rates in 5–19 year olds for total obesity-related diagnoses increased more than four-fold from 93.0 (95% CI 86.0 to 100.0) per million children to 414.0 (95% CI 410.7 to 417.5) per million children, largely due to rising admissions where obesity was mentioned as a co-morbidity. The median age of admission to hospital over the study period was 14.0 years; 5,566 (26.7%) admissions were for obesity and 15,319 (73.3%) mentioned obesity as a comorbidity. Admissions were more common in girls than boys (56.2% v 43.8%). The most common reasons for admission where obesity was a comorbid condition were sleep apnoea, asthma, and complications of pregnancy. The number of bariatric surgery procedures has risen from 1 per year in 2000 to 31 in 2009, with the majority were performed in obese girls (75.6%) aged 13–19 years.

Conclusions

Hospital admission rates for obesity and related comorbid conditions have increased more than four-fold over the past decade amongst children and young people. Although some of the increase is likely to be due to improved case ascertainment, conditions associated with obesity in children and young people are imposing greater challenges for health care providers in English hospitals. Most inpatient care is directed at dealing with associated conditions rather than primary assessment and management of obesity itself.     

Comparative Estimation of Genetic Diversity in Population Studies using Molecular Sampling and Traditional Sampling Methods

Entomopathogenic nematodes (EPN) are efficient biological pest control agents. Population genetics studies on EPN are seldom known. Therefore, it is of interest to evaluate the significance of molecular sampling method (MSM) for accuracy, time needed, and cost effectiveness over traditional sampling method (TSM). The study was conducted at the Mohican Hills golf course at the state of Ohio where the EPN H. bacteriophora has been monitored for 18 years. The nematode population occupies an area of approximately 3700 m² with density range from 0.25-2 per gram soil. Genetic diversity of EPN was studied by molecular sampling method (MSM) and traditional sampling method (TSM) using the mitochondrial gene pcox1. The MSM picked 88% in compared to TSM with only 30% of sequenced cox 1 gene. All studied genetic polymorphism measures (sequence and haplotype) showed high levels of genetic diversity of MSM over TSM. MSM minimizes the chance of mitochondrial genes amplification from non target organisms (insect or other contaminating microorganisms). Moreover, it allows the sampling of more individuals with a reliable and credible representative sample size. Thus, we show that MSM supersedes TSM in labour intensity, time consumption and requirement of no special experience and efficiency.     

Sildenafil attenuates pulmonary inflammation and fibrin deposition, mortality and right ventricular hypertrophy in neonatal hyperoxic lung injury

Background

Phosphodiesterase-5 inhibition with sildenafil has been used to treat severe pulmonary hypertension and bronchopulmonary dysplasia (BPD), a chronic lung disease in very preterm infants who were mechanically ventilated for respiratory distress syndrome.

Methods

Sildenafil treatment was investigated in 2 models of experimental BPD: a lethal neonatal model, in which rat pups were continuously exposed to hyperoxia and treated daily with sildenafil (50–150 mg/kg body weight/day; injected subcutaneously) and a neonatal lung injury-recovery model in which rat pups were exposed to hyperoxia for 9 days, followed by 9 days of recovery in room air and started sildenafil treatment on day 6 of hyperoxia exposure. Parameters investigated include survival, histopathology, fibrin deposition, alveolar vascular leakage, right ventricular hypertrophy, and differential mRNA expression in lung and heart tissue.

Results

Prophylactic treatment with an optimal dose of sildenafil (2 × 50 mg/kg/day) significantly increased lung cGMP levels, prolonged median survival, reduced fibrin deposition, total protein content in bronchoalveolar lavage fluid, inflammation and septum thickness. Treatment with sildenafil partially corrected the differential mRNA expression of amphiregulin, plasminogen activator inhibitor-1, fibroblast growth factor receptor-4 and vascular endothelial growth factor receptor-2 in the lung and of brain and c-type natriuretic peptides and the natriuretic peptide receptors NPR-A, -B, and -C in the right ventricle. In the lethal and injury-recovery model we demonstrated improved alveolarization and angiogenesis by attenuating mean linear intercept and arteriolar wall thickness and increasing pulmonary blood vessel density, and right ventricular hypertrophy (RVH).

Conclusion

Sildenafil treatment, started simultaneously with exposure to hyperoxia after birth, prolongs survival, increases pulmonary cGMP levels, reduces the pulmonary inflammatory response, fibrin deposition and RVH, and stimulates alveolarization. Initiation of sildenafil treatment after hyperoxic lung injury and continued during room air recovery improves alveolarization and restores pulmonary angiogenesis and RVH in experimental BPD.     

XcisClique: analysis of regulatory bicliques

Background  

Modeling of cis-elements or regulatory motifs in promoter (upstream) regions of genes is a challenging computational problem. In this work, set of regulatory motifs simultaneously present in the promoters of a set of genes is modeled as a biclique in a suitably defined bipartite graph. A biologically meaningful co-occurrence of multiple cis-elements in a gene promoter is assessed by the combined analysis of genomic and gene expression data. Greater statistical significance is associated with a set of genes that shares a common set of regulatory motifs, while simultaneously exhibiting highly correlated gene expression under given experimental conditions.     

Proprotein convertase subtilisin/kexin type 9 (PCSK9) affects gene expression pathways beyond cholesterol metabolism in liver cells

Proprotein convertase subtilisin/kexin type 9 (PCSK9) induces degradation of low‐density lipoprotein receptor (LDLR) in the liver. It is being pursued as a therapeutic target for LDL‐cholesterol reduction. Earlier genome‐wide gene expression studies showed that PCSK9 over‐expression in HepG2 cells resulted in up‐regulation of genes in cholesterol biosynthesis and down‐regulation of genes in stress response pathways; however, it was not known whether these changes were directly regulated by PCSK9 or were secondary to PCSK9‐induced changes to the intracellular environment. In order to further understand the biological function of PCSK9 we treated HepG2 cells with purified recombinant wild type (WT) and D374Y gain‐of‐function PCSK9 proteins for 8, 24, and 48 h, and used microarray analysis to identify genome‐wide expression changes and pathways. These results were compared to the changes induced by culturing HepG2 cells in cholesterol‐free medium, mimicking the intracellular environment of cholesterol starvation. We determined that PCSK9‐induced up‐regulation of cholesterol biosynthesis genes resulted from intracellular cholesterol starvation. In addition, we identified novel pathways that are presumably regulated by PCSK9 and are independent of its effects on cholesterol uptake. These pathways included “protein ubiquitination,” “xenobiotic metabolism,” “cell cycle,” and “inflammation and stress response.” Our results indicate that PCSK9 affects metabolic pathways beyond cholesterol metabolism in HepG2 cells. J. Cell. Physiol. 224:273–281, 2010 © 2010 Wiley‐Liss, Inc.