Significant reduction in post-lumbar puncture headache using an atraumatic needle. A double-blind, controlled clinical trial

A characteristic headache occurs in about 36-55% of patients after lumbar puncture, and many of these patients need bed rest for one or more days to get relief. In a double-blind randomized trial we compared a new 22-gauge atraumatic puncture needle with the most widely used 20-gauge "conventional" needle. In 49 patients randomized to the atraumatic needle, post-lumbar puncture headache occurred in 6%, whereas in the 50 patients randomized to the conventional needle this occurred in 32% (p = 0.001). On the basis of these results we recommend use of the atraumatic needle in order to diminish the frequency of post-lumbar puncture headache.     

Regulation of renal Na-K-Cl cotransporter NKCC2 by humoral natriuretic factors: relevance in hypertension

A furosemide-sensitive Na-K-Cl cotransporter (NKCC2 isoform) accounts for almost all luminal NaCl reabsorption in the thick ascending limb of Henle's loop (TALH). The activity of this transport protein is regulated by humoral factors (CIF: cotransport inhibitory factors). One family of CIF compounds is represented by the urinary phytoestrogens equol and genistein, which inhibit cotransport fluxes at similar concentrations as furosemide. Moreover, they possess similar salidiuretic potency as furosemide in the isolated perfused rat kidney, but are less potent than furosemide in vivo. Thus, dietary phytoestrogens can be responsible, at least in part, for the low blood pressure of vegetarians. A second type of CIF is represented by a circulating and urinary factor which is evoked by salt-loading. This, which is not a "ouabain-like" factor, appears to be a new retropituitary natriuretic compound. Endogenous CIF is increased in hypertensive Dahl salt-sensitive rats, probably as a compensatory mechanism against the enhanced NaCl reabsorption in the TALH, which characterizes this model of hypertension. Finally, chronic excess of circulating CIF inhibits and induces up-regulation of erythrocyte Na-K-Cl cotransporter NKCC1.     

Anger and blood pressure readings in children

The number of dual-specificity protein tyrosine phosphatases has grown considerably in the last few years, and thus it would be helpful to organize these novel enzymes. The simple term "VH1-like" or "dual-specificity" phosphatase does not adequately reflect the different subclasses within this new and important phosphatase subfamily. In this article, we review the salient features of dual-specificity phosphatases and propose a novel classification scheme of these enzymes based on their structural motifs. Classification of dual-specificity phosphatases based on their motifs should serve as a useful organizational framework for bringing together this now large subgroup of phosphatases. Moreover, this classification scheme may hold predictive value, since some of these motifs may hold the key to new, undiscovered functional properties.     

Some New Properties of Negation of a Probability Distribution

The properties of negation of a probability distribution recently defined by Yager 1 are studied. Furthermore, the negation of joint and marginal probability distributions in the bivariate case has been defined and their properties are studied. Finally, we have defined a new entropy function for determination of uncertainty associated with the negation of a probability distribution and the events associated with it.     

Sodium alginate incorporated with magnesium nitrate as a novel solid biopolymer electrolyte for magnesium-ion batteries

Solid biopolymer electrolytes have gained much attention in recent years. Due to their various advantages, it can be used in advanced electrochemical devices. The present study focuses on synthesizing and characterizing natural solid biopolymer electrolytes that consist of sodium alginate as the host polymer and magnesium nitrate (Mg(NO₃)₂.6H₂O) as the ionic dopant via solution casting technique. X-ray diffraction analysis of prepared solid biopolymer electrolytes validates the increase in the amorphous nature as salt concentration increases. The interaction and the complexation between the host biopolymer and the magnesium salt are confirmed by Fourier transforms infrared spectroscopy. The solid biopolymer electrolyte composition of 40 M wt.% NaAlg:60 M wt.% Mg(NO₃)₂·6H₂O possesses optimum ionic conductivity value of the order of 4.58?×?10^?3 S cm^?1 as observed by the AC impedance spectroscopy analysis at room temperature. The glass transition temperature (T_g) of the prepared solid biopolymer electrolytes has been studied using differential scanning calorimetry. Linear sweep voltammetry study reveals that the highest magnesium ion-conducting membrane has electrochemical stability of 3.5 V. Further, an optimum ionic conducting solid biopolymer membrane (40 M wt.% NaAlg:60 M wt.% Mg(NO₃)₂·6H₂O) has been utilized to fabricate a primary magnesium ion conducting battery. The open circuit voltage of the proposed solid biopolymer membrane is 1.93 V, and the performance of the battery has been studied.

     

Genetic regulation of enterocyte function: a quantitative in situ hybridisation study of lactase-phlorizin hydrolase and Na(+)-glucose cotransporter mRNAs in rabbit small intestine

The enterocyte undergoes sequential changes in its structure and function as it migrates rapidly from the small intestinal crypts to the villus tip. The mechanisms by which these changes are regulated "in tune" with ontogenic and dietary changes in the luminal environment are currently under investigation. This study has employed oligonucleotide probes to follow the expression of the lactase-phlorizin hydrolase (LPH) and Na(+)-glucose cotransporter (SGLT1) genes in rabbit small intestine using quantitative in situ hybridisation histochemistry. The profiles of LPH mRNA and SGLT1 mRNA accumulation along the crypt-villus axis were found to be very similar. Although mRNA was undetectable in the crypt. LPH and SGLT1 mRNA levels rose rapidly at the crypt-villus junction, reaching a maximum between 210 microns and 330 microns above this point. Further up the villus the level of mRNAs declined. SGLT1 mRNA was present in all small intestinal segments (duodenum, jejunum and ileum), whereas LPH mRNA was absent from the ileum. LPH activity rose and fell in conjunction with mRNA, but SGLT1 activity was greatest at the villus tip where mRNA levels were considerably reduced. These data have been used to discuss the genetic regulation of enterocyte differentiation and function.     

Molecular approaches to diagnosis of Chagas' disease: use of defined antigens and a target ribosomal RNA sequence

We evaluated the performance of two defined antigens in the serological diagnosis of Chagas' disease. One of them is a recombinant protein named B13 isolated from a genomic library of Trypanosoma cruzi in the expression vector lambda gtll. We show that the gene corresponding to B13 is conserved in the evolutive stages of the two "polar" strains of T. cruzi. The protein epitopes cloned in B13 are represented in 140 kDa, 116 kDa and 35 kDa polypeptides of trypomastigotes. The other antigen chosen for serodiagnosis is a lipopeptidophosphoglycan (LPPG). This glycoconjugate is also widely distributed in T. cruzi strains. The use of a rabbit serum to LPPG allowed the demonstration that this molecule bears epitopes in common to LPPG-like components and to 80-90 kDa glycoproteins of trypomastigotes. Both B13 and LPPG were evaluated in serodiagnosis by ELISA and RIA using a panel of normal human, Chagasic and Leishmaniasis sera. It was observed that B13 presents high sensitivity and specificity for Chagasic sera. For LPPG it was also concluded that this reagent discriminates between individuals infected and non-infected with T. cruzi. A heterogeneity in the level of antibodies to LPPG in Chagasic patients was detected. No correlation was found between the clinical form of Chagas' disease and the preferential reactivity to B13 or LPPG. We also report preliminary studies towards the characterization of a 100 bp sequence of the 24S alpha rRNA as a target for DNA-based detection systems for diagnosis. We show that polymerase chain reaction of total DNA of different trypanosomatids lead to the specific amplification of a 100 bp fragment only for T. cruzi. Northern blots confirmed the presence of the target region in the mature 24S alpha rRNA. Titration experiments based on the direct amplification of RNA with Taq DNA polymerase allowed the detection of 50 parasites. Studies are in progress to increase the sensitivity of the proposed system.     

Hematologic effects of benzene. Job-specific trends during the first year of employment among a cohort of benzene-exposed rubber workers

Hematologic surveillance data from 1940 to 1975 were analyzed for a benzene-exposed cohort of 459 rubber workers. The present analyses are restricted to 161 workers with "preemployment" counts done before exposure and rely on their subsequent counts from the first 12 months of employment. While blood cell counts declined approximately 1000 cells/mm3 over the first 4 months of exposure. Using repeated-measures analysis of variance, workers exposed above the median benzene exposure at the plant had significantly lower average white and red blood cell counts at each month during the first year of work when compared with workers exposed below the median. These decreased counts suggest that clinically detectable bone marrow depression accompanied the onset of work in this plant during the 1940s and support exposure assessments that favor higher benzene levels in the 1940s when compared with subsequent decades. The general utility of repeated-measures analytic techniques for medical surveillance data is also demonstrated by this analysis.