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Biomedical subjects

M Hussain

Publications and source records attributed to M Hussain.

At least 19 recordsLinked to original sources
PubMed2026

Enterococcus faecalis GP1764 induces an early differential gene expression in the intestine on key pathways related to cellular immune response and gut barrier function in chickens.

The aim of the present study was to elucidate the mode of action of Enterococcus faecalis GP1764 in improving performance traits during the starter phase by analyzing genome-wide gene expression and its interaction with microbial populations in the intestine of chickens challenged with an NSP-rich diet. At day 7, microbiota populations from ileal and cecal contents and transcriptomics from jejunal and cecal mucosa were analyzed between Control (Ctrl) and Enterococcus faecalis GP1764 (EntF) groups. Results from microbiota analysis demonstrated that EntF shifted β-diversity indices in ileum (neutral (p= 0.006) and phylogenetic (p= 0.006)) and caecum (phylogenetic (p= 0.017)). Transcriptomics revealed 43 differentially expressed genes for EntF vs. Ctrl in the jejunal mucosa. Of these, MHCY-36 (MHC-I-Related), RAG2 and MUC19-like genes were upregulated in EntF vs. Ctrl, protein-coding genes with immunomodulatory capacities as supported by GSEA and Cytoscape-ClueGo pathway analyses. Results suggest an intestinal immunomodulation induced through presentation of B vitamins metabolites, synthetized by EntF, to an undescribed subset of innate-like unconventional T lymphocytes in chickens, similar to MAIT cells in mammals. These cells could contribute to antibacterial responses and repair of damaged barrier tissue after inflammatory processes. The upregulation of the MUC19-like gene expression observed in the jejunal mucosa can protect gut integrity via the promotion of mucus production by goblet cells. Finally, RAG2, involved in V(D)J coding segments recombination in B- and T-cells may provide a greater recognition of foreign invaders, allowing the animals to efficiently fight against pathogenic infections. Collectively, these results suggest an important role of EntF in promoting the capacity of animals to rapidly act against pathogenic challenges, herein, inducing resilience towards dietary ingredients with anti-nutritional activity that impart moderate inflammation in chickens.

Enterococcus faecalis↗
PubMed1992

Disposition kinetics of 7,12-dimethylbenz(a)anthracene in rats.

One of the most potent carcinogens is 7,12-dimethylbenz(a)anthracene (7,12-DMBA), which is used routinely to conduct studies to evaluate carcinogen inhibitors. Its pharmacokinetics have not been reported in the literature. In view of its significant effects on drug metabolizing enzymes and clearance mechanisms, it is important to know its disposition characteristics. In this study, we monitored the disposition characteristics of 7,12-DMBA in rats as a function of dose range commonly used in carcinogenesis studies. A mean residence time of 40-55 min was observed; the total body clearance ranged from 8-13 l kg-1. No effect of dose was observed on the pharmacokinetic parameters. This suggests that the dose-dependent effects of 7,12-DMBA carcinogenesis are related to its transient disposition characteristics.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1992

Importance of medium and atmosphere type to both slime production and adherence by coagulase-negative staphylococci.

Marked differences in both the production of slime and adherence by Staphylococcus epidermidis were observed when comparing four culture media. Slime isolated from a strain cultured in a chemically defined medium (HHW) in air was chemically indistinguishable from that formed in both HHW and synthetic dialysis fluid (SDF) in air with 5% CO2. The presence of a physiological level of CO2 during culture in tryptone soya broth (TSB) prevented production of slime. It was not possible to separate the constituents of slime from those of the culture medium in bacteria grown in TSB in air using DEAE cellulose. Slime production was notably poor in used peritoneal dialysis fluid (PUD). Adherent growth was marked in HHW and SDF but was poor in TSB and PUD when air with 5% CO2 was used. These findings emphasize the advantages in using chemically defined and biological fluids when studying slime production and adherence by S. epidermidis.

Bacterial Adhesion↗
PubMed1992

Radiochemical assay to measure the biofilm produced by coagulase-negative staphylococci on solid surfaces and its use to quantitate the effects of various antibacterial compounds on the formation of the biofilm.

A firmly adherent mass of slime plus organisms (biofilm) accumulates on the sides of culture tubes when some strains of coagulase-negative staphylococci are grown in a chemically-defined medium containing [14C]glucose. This mass was washed (to remove labelled medium) and then counted after adding scintillation fluid. Organisms from the liquid culture were also washed and counted to check that [14C]glucose had been utilised to label the bacteria. Nine strains were examined in this way, and the results were compared with those obtained with four older techniques for recognising slime production or adherent bacteria. The new method is quick, and has advantages of reproducibility and good discrimination between strains; there was a 15-fold difference in counts in the biofilm between slime-producing and non-producing strains respectively. With the new radiolabel assay, the effects of several antibacterial compounds on the build-up of the biofilm were investigated with four slime-producing strains. Tunicamycin, chloramphenicol and 5-fluorouracil, at levels below their minimum growth-inhibitory concentrations, each greatly diminished biofilm formation; several other drugs had less effect.

Adenosine Triphosphate↗
PubMed1992

Comparison of cell-wall teichoic acid with high-molecular-weight extracellular slime material from Staphylococcus epidermidis.

Extracellular high-mol.-wt material was separated from liquid cultures of Staphylococcus epidermidis. This material contained protein c. 20% w/w and polysaccharide c. 80% w/w. The polysaccharide was isolated by gel and ion-exchange chromatography and contained glycerol phosphate, glucose, N-acetylglucosamine, and D-alanine. Cell-wall teichoic acid was isolated from strain RP-62A and had a similar composition.

Acetylglucosamine↗
PubMed1992

A large erythroid spectrin beta-chain variant.

A large variant of erythrocyte beta-spectrin was found in a child presenting with hereditary elliptocytosis and anaemia. This polypeptide was phosphorylated, cross-reacted with normal beta-spectrin in immunoblotting and formed a dimer with alpha-spectrin that co-purified with normal alpha beta dimer. The molecular weight was estimated to be 330 kD by SDS gel electrophoresis, which is 84 kD (35%) larger than the normal beta-chain. This variant has been tentatively named spectrin Detroit (beta Detroit). Tryptic digests demonstrated a coexisting alpha-spectrin variant Sp alpha I/65 in the propositus, his father and a paternal uncle. Anaemia and elliptocytosis was associated with Sp alpha I/65 rather than beta Detroit, since other family members with beta Detroit in whom alpha-spectrin was normal had no morphological or clinical abnormalities. Family members were identified who had normal alpha-spectrin but were heterozygotic for the large beta-spectrin. Their erythrocyte membranes were more rigid and fragile than normal. The fragility is probably a consequence of both weaker dimer association and spectrin deficiency. Variant spectrin dimers (alpha beta Detroit) had a reduced self-association constants. Binding to ankyrin was normal. Instability of beta Detroit during erythropoiesis is suggested by the fact that it comprises only 25% of the beta-spectrin in beta Detroit heterozygote erythrocytes, and total spectrin was reduced by 20%. Although beta Detroit has some functional defects, this 84 kDa insert in erythrocyte spectrin is compatible with nearly normal function.

Centrifugation, Density Gradient↗
PubMed1991

Characterization of PDR4, a Saccharomyces cerevisiae gene that confers pleiotropic drug resistance in high-copy number: identity with YAP1, encoding a transcriptional activator [corrected].

PDR4 is a gene that confers pleiotropic drug resistance (pdr) to the yeast Saccharomyces cerevisiae when present in high copy number [Leppert et al., Genetics 125 (1990) 13-20]. Transposon insertion mutations had identified the active region of the gene as a 3.7-kb SalI-EcoRI restriction fragment of the 8-kb cloned fragment. We have confirmed this by showing that this fragment is sufficient to confer pdr, and have sequenced its entire 3761 bp. It contains a single complete open reading frame (ORF) extending from nucleotide (nt) position 1631-3580, coding for a protein of 650 amino acids (aa). A 2.7-kb fragment containing this ORF is also sufficient to confer pdr. The aa sequence contains no recognizable homologies or consensus sequences, so it is a novel protein of unknown function. It is apparently soluble, since no transmembrane-type sequences were predicted. A second, partial ORF was also found, on the opposite strand, extending from nt position 774 to past the SalI site, which is apparently unrelated to pdr.

Amino Acid Sequence↗
PubMed1991

The role of infection in the morbidity and mortality of patients with head and neck cancer undergoing multimodality therapy.

Cancer of the head and neck is a common cancer worldwide. The majority of patients present with locally advanced disease. Recently a great deal of improvement has been made in multimodality therapy of this disease, warranting more careful consideration of factors affecting quality of life, disease course, and treatment. Infection is clearly a factor. Analysis of 662 hospital admissions of 169 head and neck cancer patients was performed. A definite infection was documented in 86 febrile episodes, pneumonia contributed to 40%, bacteremia to 13%, skin and soft tissue infection to 12%, and tracheobronchitis to 10%. Among the evaluated risk factors, foreign bodies, specifically intravenous (IV) cannulae and gastrostomy tubes, race, performance status, alcohol intake, and nutritional status were statistically significant variables that predicted for or were associated with infection. Infection contributed to 44% of the deaths.

Adult↗
PubMed1991

Effects of serum, its protein and lipid extracts, and commercial serum proteins and lipid on the isolated frog heart.

This study investigates the inotropic effects of serum, its protein and lipid extracts, and commercial serum proteins and lipid on the isolated, spontaneously-beating heart and superfused, hypodynamic ventricle of the frog. Serum taken from either man, horse, calf, frog, or rabbit evoked marked positive inotropic responses which were unaffected by cholinergic, serotonergic, and adrenergic receptor antagonists. Dialysed serum (dialisand) and void volume fractions from Sephadex G200-120 columns corresponding to large molecular weight constituents evoked marked positive inotropic responses. When serum was separated into fractions containing either proteins or lipids/lipoproteins by high-density ultracentrifugation or activated charcoal, both extracts evoked marked positive inotropic responses. Commercial serum globulins and serum containing a high proportion of immunoglobulins elicited large increases in contractile force, whereas serum albumin evoked a negative inotropic effect. Serum which was either boiled and/or treated with chymotrypsin to denature proteins also caused a marked increase in isometric twitch tension in the frog heart. Similar inotropic response was obtained with fractions of boiled serum eluted on columns of Sephadex G200-120. These fractions corresponded to molecular weight in the region of 60-70 kDa. However, the inotropic effect of boiled serum was abolished following pretreatment with lipase. Superfusion of frog hearts with commercial cardiolipin resulted in marked dose-dependent increases in contractile force. The results demonstrate the presence of at least two large molecular weight cardioactive principles in serum. These substances are comparable in size to constituents of serum proteins (e.g., globulins and immunoglobulins) and serum lipids/lipoproteins (e.g., cardiolipin) and may serve as physiological regulators of cardiac function.

Animals↗
PubMed1991

Alpha 1-antitrypsin deficiency and liver disease: clinical presentation, diagnosis and treatment.

The alpha 1-antitrypsin deficient subject (protease inhibitor (PI) phenotype ZZ) has an increased susceptibility to liver disease. The condition is most commonly identified in early infancy as a conjugated hyperbilirubinaemia with hepatitis (11%) or a bleeding state due to vitamin K malabsorption (2%). 50% of cases have cirrhosis and 25% die in the first decade of life. A further 2% present with cirrhosis in later childhood. Adult males are at risk of hepatoma development with or without cirrhosis. Diagnosis is by isoelectric focussing or allele-specific oligonucleotide hybridization. The treatment is that of cholestasis and cirrhosis including transplantation. The pathobiology of the deficiency state, the mechanism of liver damage and the vulnerability of the newborn liver are discussed in this review. A plea is made for a trial of infusions of alpha 1-antitrypsin in early infancy, as is used safely but without proven efficacy in the emphysematous PIZZ subject. Prospects of therapy by gene modification are also reviewed.

Humans↗
PubMed1991

Isolation and composition of the extracellular slime made by coagulase-negative staphylococci in a chemically defined medium.

Slime isolated after growth of four strains of coagulase-negative staphylococci on chemically defined medium plus agar was rich in galactose. However, when sterile agar plates were extracted with saline, high-molecular-weight material with similar properties was obtained that also was galactose-rich. Most of the dry weight attributed to slime, and probably all the galactose, originated from agar. Slime isolated by gel and ion-exchange chromatography from liquid culture in the same medium contained glycerol phosphate, glucose (no galactose), glucosamine, alanine, uronate, an unidentified component, and protein. Separation of protein from carbohydrate was achieved by affinity chromatography. [14C]glucose in the medium labeled the carbohydrate polymer; [14C]amino acids chiefly labeled extracellular proteins. Slime from bacteria grown on medium solidified with silica gel or on dialysis membrane above an agar surface showed essentially the same composition and behavior after purification as the material isolated from liquid culture.

Chemical Fractionation↗