Benzoate modulates renal and extrarenal nitrogen flow: metabolic mechanisms.

The mechanism by which benzoate enhances total nitrogen excretion was investigated in-situ and in separated rat renal proximal tubules. Orally administered benzoate augmented NH4+, urea and hippurate excretion 2, 1.9 and 76 fold respectively, as compared to baseline for control. Hippurate had similar effects. Benzoate augmented renal blood flow, glutamine extraction and total NH4+ production. Arterio-venous concentration differences of glutamine, glutamate, and NH4+ across the kidney, liver and gut demonstrated an increase in glutamine uptake by the kidney despite reduced release and uptake by the liver and gut, respectively; glutamate release by the kidney and gut was increased; NH4+ handling was unchanged at these three organs. Studies in separated rat renal proximal tubules demonstrated that benzoate stimulated glutamine dependent ammonia-genesis by activation of gamma-glutamyltransferase, via the synthesis of hippurate. The results demonstrate that benzoate can modulate the interorgan partitioning of nitrogen metabolites across several organs, the net effect of which is physiologically expressed as enhanced NH4+ , urea and hippurate excretion.     

Response of Asthmatics to Isoprenaline and Salbutamol Aerosols Administered by Intermittent Positive-pressure Ventilation

The bronchodilator and cardiac effects produced by aerosols of 0·5% isoprenaline and of 0·25, 0·5, and 1% salbutamol administered in 40% oxygen by intermittent positive-pressure ventilation were compared in 24 asthmatic patients. Isoprenaline and salbutamol in concentrations of 0·5% were equipotent in peak bronchodilator effect; salbutamol was superior in total bronchodilator effect and duration of average effect, but the peak bronchodilator effect occurred earlier after isoprenaline. Significantly greater tachycardia was produced by 0·5% isoprenaline than by the same concentration of salbutamol. The 0·25, 0·5, and 1% concentrations of salbutamol had about the same peak bronchodilator effect, but there was a stepwise increase in total effect and duration of average effect in relation to the concentration used. A similar stepwise increase in heart rate was also noted, but with all concentrations this was significantly less than with 0·5% isoprenaline. It was concluded that a 0·5% solution of salbutamol, which provided maximal bronchodilatation without important tachycardia, was therapeutically superior to the other three treatments.     

Mass spectrometric quantification of endogenous beta-endorphin

Fast atom bombardment (FAB) mass spectrometry and multiple reaction monitoring (MRM) in the B/E linked-field scan mode were used to quantify endogenous beta-endorphin (BE) in individual human pituitary extracts. The experimental protocol includes the addition of a stable isotope-labeled internal standard ((2H4-Ile22)BE1-31, human) to the tissue homogenate before extraction, purification of the native BE by a combination of Sep-Pak chromatography and gradient high-performance liquid chromatography (HPLC), trypsin digestion to cleave BE into smaller peptides, and separation of the tryptic fragment BE20-24 (NAIIK) by isocratic reversed-phase HPLC. Mass spectrometric quantification is based upon recording either (a) the [M + H]+ ions of NAIIK and its deuterated analog ((2H4)NAIIK), or (b) the transitions ([NAIIK + H](+)----[NAI]+) and [((2H4)NAIIK + H](+)----[(2H4)NAI]+) using the B/E linked-field scan. Linear calibration curves were obtained using these two mass spectrometric techniques from standard solutions containing 1.25-20 micrograms of BE; each standard solution also contained 10 micrograms of (2H4)BE. The amounts (means +/- s.d.) of endogenous BE in five separate human pituitaries were found to be 156 +/- 84 [( M + H]+ method) and 169 +/- 99 pmol mg-1 protein (MRM method).     

Synchronisation of oestrus of goats treated with progestagen-impregnated intravaginal sponges and PMSG,and reproductive performance following natural mating or A.I. with frozen semen

Oestrus was synchronised in 88 goats using progestagen-impregnated intravaginal sponges (60 mg Repromap; Upjohn) left in place for 17 days, followed by intramuscular injection of PMSG (300 i.u.) at sponge withdrawal. The percentages of does that came into oestrus in 0–24, 25–48, 49–72 and 73–96 h periods were 42, 30.5, 10.5 and 6.5 (cumulative 89.5%). The time of onset of oestrus ranged from 16 to 40 h. Breeding at the synchronised oestrus using intact bucks (24–96 h) or artificial insemination with frozen-thawed semen, at fixed times of 24, 48, 72 and 96 h, resulted in 71% and 81% conceptions respectively. Intrauterine deposition of semen was possible in 31.3%, 62.5%, 87.5% and 6.3% of cases at 24, 48, 72 and 96 h respectively. Twinning percentages were 54.5% and 56% for natural mating and artificial insemination. Kidding was spread over a 14-day period with mean gestation lengths of 149 days for singletons and 147 days for twins. The results indicate that use of progestagen-impregnated sponges with PMSG is an efficient method of synchronisation of oestrus and may result in increased fertility in goats and, if used with A.I. with frozen semen, may contribute to increased breeding efficiency and rate of genetic improvement of goats in Asia.     

Adsorption of adipic acid in Al/B-N/P nanocages: DFT investigations

The biomolecular recognition of D-mannose-binding lectin from Artocarpus heterophyllus (ArtinM) by Horseradish Peroxidase (HRP) mediated by glycosylation allows their application in a multitude of biological systems. The present work describes the use of molecular dynamics (MD) to assess the Gibbs free energy associated with the formation of a ArtinM-HRP conjugate mediated by a glycosylation molecule. For the enthalpy term, we applied the molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) method and for the vibrational entropy term, we use the quasi-harmonic approximation. Our results show that, even without glycosylation, the binding free energy between ArtinM and HRP is − 196.154 kJmol^− 1, an extremely high affinity with low selectivity, originated mainly through the van der Waals energy terms. The binding free energy between ArtinM and the glycosylated HRP (gHRP) was calculated at − 66.156 kJmol^− 1, an absolute and considerably lower value, however, originated from electrostatic energy terms, which increases the selectivity of molecular recognition. Our work has shown that the HRP active site region has a high affinity and low selectivity for other biomolecules. The presence of glycosylation plays a role in increasing this selectivity for this region. Thus, we conclude that performing mutagenesis of amino acid residues near the entrance of the catalytic site, can improve the activity of non-glycosylated HRPs. This illustrates new insights that can be applied to carbohydrate-based immunochemistry.

     

Codon usage of human hepatitis C virus clearance genes in relation to its expression

Hepatitis C virus (HCV) infection is among the leading causes of hepatocellular carcinoma and liver cirrhosis globally, with a high economic burden. The disease progression is well established, but less is known about the spontaneous HCV infection clearance. This study tries to establish the relationship between codon biasness and expression of HCV clearance candidate genes in normal and HCV infected liver tissues. A total of 112 coding sequences comprising 151 679 codons were subjected to the computation of codon indices, namely relative synonymous codon usage, an effective number of codon (Nc), frequency of optimal codon, codon adaptation index, codon bias index, and base compositions. Codon indices report of GC3s, GC12, hydropathicity, and aromaticity implicates both mutational and translational selection in the candidate gene set. This was further correlated with the differentially expressed genes among the selected genes using BioGPS. A significant correlation is observed between the gene expression of normal liver and cancerous liver tissues with codon bias (Nc). Gene expression is also correlated with relative codon bias values, indicating that CCL5, APOA2, CD28, IFITM1, and TNFSF4 genes have higher expression. These results are quite encouraging in selecting the high responsive genes in HCV clearance. However, there could be additional genes which could also orchestrate the clearance role with the above mentioned first line of defensive genes.