Parathyroid hormone regulation of NA+,K+-ATPase requires the PDZ 1 domain of sodium hydrogen exchanger regulatory factor-1 in opossum kidney cells

It was demonstrated that expression of murine sodium hydrogen exchanger regulatory factor (NHERF-1) lacking the ezrin-binding domain blocks parathyroid hormone (PTH) regulation of Na+,K+-ATPase in opossum kidney (OK) cells. The hypothesis that the NHERF-1 PDZ domains contribute to PTH regulation of Na+,K+-ATPase was tested by comparison of PTH regulation of Na+,K+-ATPase in wild-type OK (OK-WT) cells, NHERF-deficient OKH cells, OK-WT transfected with siRNA for NHERF (NHERF siRNA OK-WT), and OKH cells that were stably transfected with full-length NHERF-1 or constructs with mutated PDZ domains. OKH cells and NHERF siRNA OK-WT showed decreased expression of NHERF-1 but equivalent expression of ezrin and Na+,K+-ATPase alpha1 subunit when compared with OK-WT cells. PTH decreased Na+,K+-ATPase activity and stimulated phosphorylation of the Na+,K+-ATPase alpha1 in OK-WT cells but not in NHERF-deficient cells. Rubidium (86Rb) uptake was equivalent in OK-WT, OKH, and OKH cells that were transfected with all but the double PDZ domain mutants. PTH decreased 86Rb uptake significantly in OK-WT but not in OKH cells. PTH also significantly inhibited 86Rb uptake in OKH cells that were transfected with full-length NHERF-1 or NHERF-1 with mutated PDZ 2 but not in OKH cells that were transfected with mutated PDZ 1. Transfection with NHERF expressing both mutated PDZ domains resulted in diminished basal 86Rb uptake that was not inhibited further by PTH. PTH stimulated protein kinase Calpha activity and alpha1 subunit phosphorylation in OK-WT but not in NHERF-deficient cells. Transfection of OKH cells with NHERF constructs that contained an intact PDZ1 domain restored PTH-stimulated protein kinase Calpha activity and alpha1 subunit phosphorylation. These results demonstrate that NHERF-1 is necessary for PTH-mediated inhibition of Na+,K+-ATPase activity and that the inhibition is mediated through the PDZ1, not PDZ2, domain.     

Technetium-99m-L,L-ethylenedicysteine renal scan as a single-modality investigation for the evaluation of renal morphology and function: a comparative study with technetium-99m-dimercaptosuccinic acid

AIM: To evaluate whether cortical scars can be detected using the summed images of technetium-99m-L,L-ethylenedicysteine (99mTc-L,L-EC) renal dynamic scan, and to compare the results with technetium-99m-dimercaptosuccinic acid (99mTc-DMSA) scan. To evaluate the inter-observer variability for 99mTc-L,L-EC and 99mTc-DMSA scan reporting. METHODS: One hundred and three patients were initially included in the study; 21 were excluded, five due to a single functioning kidney and 16 due to impaired renal function (serum creatinine>2.5 mg.dl(-1)). Eighty-two patients (39 females, 43 males), including 31 children, with a mean age of 33.4+/-11.3 years (range, 4 months to 74 years), underwent both 99mTc-DMSA and 99mTc-L,L-EC scintigraphy within a period of 14 days. 99mTc-L,L-EC images were regrouped into 2 min image sets, and the initial 2 min summed image (cortical phase) was used for the evaluation of scars. Three independent observers analysed both images separately on different days without being aware of the identity and clinical details of the patients. Their 99mTc-L,L-EC findings were compared with the consensus 99mTc-DMSA scan findings taken as reference. RESULTS: The overall sensitivity of 99mTc-L,L-EC scans was 93% and the specificity was 96%. The inter-observer variability was 0.91 for 99mTc-L,L-EC and 0.94 for 99mTc-DMSA scan reporting, using the weighted kappa analysis at P<0.05. CONCLUSIONS: 99mTc-L,L-EC is an excellent single-modality comprehensive investigational agent for renal morphology, function and outflow tract evaluation with the added advantages of lower cost, convenience and low radiation exposure to the patient.     

Synthesis and selective cyclooxygenase-2 inhibitory activity of a series of novel, nitric oxide donor-containing pyrazoles

The synthesis of a series of novel pyrazoles containing a nitrate (ONO(2)) moiety as a nitric oxide (NO)-donor functionality is reported. Their COX-1 and COX-2 inhibitory activities in human whole blood are profiled. Our data demonstrate that pyrazole ring substituents play an important role in COX-2 selective inhibition, such that a cycloalkyl pyrazole (6b) was found to be a potent and selective COX-2 inhibitor. Other modifications at the 3 position of the central pyrazole ring (17b, 23b, 26b-I) enhanced COX-2 inhibitory potency. Among the pyrazoles synthesized, the oxime (23b) was identified as the most potent COX-2 selective inhibitor. Accordingly, 23b was profiled pharmacologically in the rat after oral administration and shown to possess potent antiinflammatory activity in the carrageenan-induced air-pouch model and less gastric toxicity than a standard COX-2 inhibitor when administered with background aspirin treatment. We suggest that the enhanced gastric tolerance of an NO-donor COX-2 selective inhibitor has the potential to augment the clinical profile of this drug class.     

Neurodegenerative disease and iron storage in the brain

PURPOSE OF REVIEW: Iron is very important for normal regulation of various metabolic pathways. Neurons store iron in the form of ferrous ion or neuromelanin. In specific disorders the axonal transport of iron is impaired, leading to iron deposition which in the presence of reactive oxygen species results in neurodegeneration. RECENT FINDINGS: Recent developments in genetics, including the finding of mutations in the pantothenate kinase gene and ferritin light chain gene, have demonstrated a direct relationship between the presence of a mutation in the iron-regulatory pathways and iron deposition in the brain resulting in neurodegeneration. These two disorders now add to our understanding of the mechanism of disease due to dysfunction of iron-regulatory pathways. In addition to these disorders there may be several other mutations of iron-regulatory genes or related genes that are yet to be found. The animal models of disease have also added value to this area. SUMMARY: In this review we provide a summary of recent developments in the field of movement disorders with abnormalities in iron transport, and the current evidence in neurodegenerative disorders such as Parkinson's disease.     

Social and economic impact of childhood asthma

In order to assess the social, educational and economic impact in children with asthma and their families, we studied 162 children with bronchial asthma. The patients and their parents were interviewed to assess the restriction on various activities of the child and family, the impact on schooling and expenditure on therapy. One hundred and forty one (87%) children had either mild or moderate persistent asthma. Nearly two thirds of children had some restriction placed on their play activities because of asthma. Restrictions on other physical activities and social activities were reported in half the children. Children had absented from school for a median of 4 days in preceding 6 months. All these restrictions were more common in children with more severe disease and/or poor control of symptoms. The median monthly expenditure on child's medication was Rs. 333, i.e., about one third of monthly per capita income. Childhood asthma has significant adverse impact on child's daily activities, schooling, and family life and finances.     

Anomalous flexor digiti minimi brevis in Guyon's canal

In an adult male cadaver, the flexor digiti minimi brevis, a muscle of the hypothenar eminence, was found to arise from the superficial transverse septum (between the superficially placed flexor carpi ulnaris, palmaris longus, and flexor carpi radialis muscles, and the deeply placed flexor digitorum superficialis muscle) in the distal fourth of the flexor aspect of the left forearm. The muscle exhibited two strata of muscle fibers at its origin. The superficial stratum was a thin layer of transversely running fibers confined to the forearm, which has not been previously reported. The deep stratum, a thick layer of longitudinally running fibers, formed the bulk of the muscle. It traversed Guyon's canal superficial to the ulnar nerve and vessels to reach the hypothenar eminence. Its course through Guyon's canal could be a cause for ulnar tunnel syndrome. The ulnar nerve trunk innervated not only the anomalous flexor digiti minimi brevis muscle, but also abductor digiti minimi and palmaris brevis. This may be due to the common phylogeny of these three muscles from the same muscle mass.     

Genotyping of Hepatitis C virus (HCV) in infected patients from South India

Hepatitis C virus shows substantial nucleotide sequence diversity distributed throughout the viral genome. In the present study genotyping for Hepatitis C virus (HCV) infected patients was based on RFLP analysis of 5' UTR and using type specific primers of NS5B regions. It was observed that 60% of the patients (30 patients with chronic hepatitis) were infected with variants of genotype 1 and 40% of the patients (4 chronic hepatitis patients, 12 patients with chronic renal failure and 4 cirrhosis) were infected with variants of type 3 of HCV. None of the cirrhotic patients and patients with chronic renal failure, in the present study, were infected with type 1 of HCV. While PCR-RFLP, typing was rapid in conjunction with the primers used for RT-PCR, NS5 typing was helpful in determining the subtype. There was good correlation between the two typing methods and this method can be used as a cost-effective method for studying large number of samples. The study shows that predominant genotypes of HCV in South India include type 1 and 3. Type 3 seems to be transmitted nosocomially as suggested by the results in patients with chronic renal failure, as these patients are exposed to multiple medical interventions.     

Reduced Resource Optimization in Male Alcoholics: N400 in a Lexical Decision Paradigm

Background: Event Related Potential (ERP) studies have highlighted some measures, notably P3 amplitude, that are associated with both state and trait deficits in alcoholism, while studies examining N400 amplitude in alcoholism are few. The present study aims to examine differences in the N400 component, an electrophysiological correlate of semantic priming, in event‐related potentials from a lexical decision task in 87 alcohol dependent subjects and 57 community controls. Methods: Each subject was presented with 300 stimuli sequentially in a quasi‐randomized design, where 150 stimuli were words and 150 were non‐words. The subjects made a lexical decision indicating the word/non‐word status with a button press. Among the words, 50 words (primed) were always preceded by their antonyms (prime, n = 50), whereas the remaining 50 words were unrelated. N400 amplitude and latency measures were compiled from ERPs to the primed and unprimed words. Corresponding reaction time (RT) and response characteristics were also analyzed. Results: Control subjects revealed a significant attenuation of the N400 response to the primed word when compared to the unprimed word. Significantly less attenuation was observed in alcohol dependent subjects. No significant group differences were seen for latency and behavioral measures. All subjects had slower RT for unprimed words compared to primed words; however significantly less RT savings between the unprimed and primed condition was noted for alcoholics. Conclusions: These results suggest a reduced flexibility in the cognitive networks and a lack of resource optimization in alcoholics. The reduced attenuation of N400 during the primed condition in the alcohol dependent subjects may reflect an inability to engage similar neuronal substrates associated with semantic relatedness as seen in the controls. As diminished N400 attenuation during priming is observed in both alcoholics and high risk subjects, it may be a marker of risk and a good endophenotype for alcoholism.     

Brain signatures of monetary loss and gain: outcome-related potentials in a single outcome gambling task

This study evaluates the event-related potential (ERP) components in a single outcome gambling task that involved monetary losses and gains. The participants were 50 healthy young volunteers (25 males and 25 females). The gambling task involved valence (loss and gain) and amount (50 cent and 10 cent) as outcomes. The outcome-related negativity (ORN/N2) and outcome-related positivity (ORP/P3) were analyzed and compared across conditions and gender. Monetary gain (compared to loss) and higher amount (50 cent compared to 10 cent) produced higher amplitudes and shorter latencies in both ORN and ORP components. Difference wave plots showed that earlier processing (200-400 ms) is dominated by the valence (loss/gain) while later processing (after 400 ms) is marked by the amount (50 cent/10 cent). Functional mapping using Low Resolution Electromagnetic Tomography (LORETA) indicated that the ORN separated the loss against gain in both genders, while the ORP activity distinguished the 50 cent against 10 cent in males. This study further strengthens the view that separate brain processes/circuitry may mediate loss and gain. Although there were no gender differences in behavioral and impulsivity scores, ORN and ORP measures for different task conditions had significant correlations with behavioral scores. This gambling paradigm may potentially offer valuable indicators to study outcome processing and impulsivity in normals as well as in clinical populations.