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Biomedical subjects

M A Hossain

Publications and source records attributed to M A Hossain.

At least 19 recordsLinked to original sources
PubMed1997

Comparison between Wako-WB003 and Fungitec G tests for detection of (1-->3)-beta-D-glucan in systemic mycosis.

The limulus factor G reacts with (1-->3)-beta-D-glucan, a major structural component of fungal cell walls. The Fungitec G test is a colorimetric assay that measures the concentration of (1-->3)-beta-D-glucan and is used as a serodiagnostic test for deep mycosis. Wako-WB003 is another assay for (1-->3)-beta-D-glucan that determines the change in turbidity of the gelatin reaction of limulus factor G with (1-->3)-beta-D-glucan. In five rabbits inoculated intravenously with 1 x 10(7) CFU of Candida albicans, the concentration of (1-->3)-beta-D-glucan measured by the fungitec G test increased gradually reaching a peak of 660.9 +/- 427.9 pg/ml (mean +/- SD) 4 days after inoculation, but to 42.225 +/- 41.275 ng/ml on day 6 in the Wako-WB003 test. In one rabbit challenged intravenously with 5 x 10(6) CFU of C. albicans, (1-->3)-beta-D-glucan increased to 101.5 pg/ml on day 4 on the fungitec G test, whereas the level remained below the detection limit of the Wako-WB003 test throughout the course of the disease. We also detected high concentrations of (1-->3)-beta-D-glucan in 11 patients with candidemia, 4 with suspected candidemia, 1 with invasive pulmonary aspergillosis, and 12 patients with aspergilloma. The concentration of (1-->3)-beta-D-glucan measured by the Fungitec G test was > 150, > 1006.8; 312.1, and 55.6 +/- 37.4 pg/ml (range, 20.1-138.0 pg/ml), and by the Wako-WB003 test > 153.000, > 17.70, 153.000 and 2.645 +/- 7.248 ng/ml (range, < 25.20 ng/ml) in these patients, respectively. In contrast, the concentration of (1-->3)-beta-D-glucan in 9 patients with pulmonary cryptococcosis and 6 with superficial candida colonization ranged from < 13.2 and < 15.3 pg/ml in the Fungitec G test and < 0.53 and < 0.12 ng/ml in Wako-WB003 test. There was a weak relationship between the concentration of (1-->3)-beta-D-glucan measured by the Fungitec G test and Wako-WB003 test (r = 0.521). Our results indicate that the sensitivity of the Wako-WB003 test is lower than that of the Fungitec G test.

Animals↗
PubMed1996

Effects of cold preservation and reperfusion on microsomal cytochrome P-450-linked monooxygenase system of the rat liver.

The effects of cold preservation and reperfusion of the liver on the hepatic microsomal cytochrome P-450-linked monooxygenase system (P-450 system) were investigated. Rat livers were preserved with cold University of Wisconsin solution for 0, 12, 24, 36, and 48 hr. Half of them in 0-, 24-, and 48-hr groups were reperfused for 1 hr at 37 degrees C with oxygenated Krebs-Henseleit buffer. After preservation or reperfusion, the liver microsomes were prepared and the concentration of each component of the P-450 system [NADPH-cytochrome b5 reductase (b5 reductase), cytochrome b5 (b5), NADPH-cytochrome P-450 reductase (P-450 reductase) and cytochrome P-450 (P-450)] and their drug metabolizing activities and concentration of apo-cytochrome P-450 2E1 (apo-P-450 2E1) were measured. After 48-hr preservation, b5 concentration did not decrease, whereas the concentration of P-450, P-450 reductase, and b5 reductase decreased from 0.865 to 0.676 nmole/mg protein, from 0.262 to 0.233 micromole/mg protein/min and from 5.34 to 4.86 micromole/mg protein/min, respectively. During cold preservation, the activities of p-nitroanisole O-demethylase and aniline p-hydroxylase did not change. Aminopyrine N-demethylase activity was inhibited from 4.45 to 3.34 nmole/mg protein/min after 48-hr cold preservation. Apo-P-450 2E1 was gradually decreased during cold preservation. Reperfusion caused a further decrease in the activities and concentration of the components of the P-450 system and concentration of apo-P-450 2E1 to 80-90% after 1-hr reperfusion. It was suggested that the prolonged preservation caused deterioration of the P-450 system and the loss of the abilities of metabolism and detoxication of xenobiotics.

Animals↗
PubMed1996

Characterization of pyruvate decarboxylase genes from rice.

The pdc1 gene encoding pyruvate decarboxylase has been isolated and sequenced from an IR54 rice genomic library. In contrast to a previously isolated intron-less rice genomic pdc, pRgpdc3, this gene contains five intervening introns in the coding region and corresponds to a cDNA clone, pRcpdc1, isolated from an IR54-cDNA library constructed from anaerobically-induced mRNAs. Comparison of the deduced amino acid sequence of this gene with that of the rice pdc2 and pdc3 showed 88% and 89% similarity, and 78% and 79% identity, respectively. Southern blots indicated that more than three genes constitute the pdc gene family in rice. pdc1 is highly inducible under anaerobic conditions. Rice pdc2 is also inducible by anoxia but to a much lesser extent than pdc1.

Aerobiosis↗
PubMed1996

Comparison of University of Wisconsin and University of Pittsburgh solutions for heart transplantation.

The effectiveness of University of Wisconsin (UW) and University of Pittsburgh (UP) solutions for the preservation of rat hearts was compared. Lewis rat hearts were preserved with UW (group A, n = 45) or UP (group B, n = 45) solution for 0 or 24 h and then transplanted heterotopically into the recipients' abdomen. Ten recipients in each group were observed to obtain 1-week graft survival rates. Tissue water content and tissue content of adenine nucleotides were measured 2 h after transplantation in six grafts from each group. Six hearts preserved for 0 h and seven hearts preserved for 24 h were taken from each group 24 h after grafting for histopathology. The 1-week graft survival rates of groups A24 and B24 were 60% and 10%, respectively. In the 24-h preserved grafts, adenosine triphosphate (ATP) and energy charge [(ATP + adenosine diphosphate/2)/(ATP + adenosine diphosphate + adenosine monophosphate)] of groups A and B were 0.972 +/- 0.165 and 0.200 +/- 0.123 mg/g wet tissue (P < 0.05) and 74.4% and 61.1% (P < 0.05), respectively. The tissue water content of group A24 was 71.7%, whereas that of group B24 was 74.1% (P < 0.05). Histopathology revealed more severe muscle edema and necrosis and infiltration of polymorphonuclear cells in group B24 than in group A24. We conclude that UW solution is more appropriate for rat heart preservation than UP solution.

Abdomen↗
PubMed1996

Impact of adhesion molecules of the selectin family on liver microcirculation at reperfusion following cold ischemia.

We investigated the role of adhesion molecules in the early phase of reperfusion following cold ischemia. Livers of male Lewis rats were preserved for 0 h (group A) or 24 h in University of Wisconsin (UW) solution without additives (group B) or in UW solution with anti-ICAM-1 antibody (group C) or anti-E-selectin-1, SLe(x) and SLe(a) antibodies (group D). The livers were then reperfused with diluted rat whole blood (DWB; groups A and B). DWB containing anti-ICAM-1 and LFA-1 antibodies (group C) or DWB containing anti-L-selectin, SLe(x) and SLe(a) antibodies (group D). The reperfusion was performed at 37 degrees C for 1 h at 5 cm H2O of perfusion pressure. During reperfusion, hepatic microcirculation was assessed by monitoring portal and peripheral tissue blood flow. Bile production was significantly reduced in group B livers compared with those in group A. Anti-ICAM-1 and LFA-1 antibodies failed to improve hepatic microcirculation, whereas anti-LECAM-1, SLe(x) and SLe(a) antibodies significantly improved the microcirculation. Bile production in group C and D livers was comparable to that in group B livers. Preservation for 24 h significantly increased the release of TNF-alpha from 0.207 to 43.7 pg/g per hour during reperfusion. Monoclonal antibodies to the adhesion molecules did not suppress the release of TNF-alpha in groups C and D. Histological examination demonstrated a lack of leukocyte infiltration or thrombus in hetapic microvessels. The extent of hepatocyte necrosis did not differ among groups B, C, and D. We conclude that the microcirculatory disturbance in the early phase of reperfusion occurs as a result of the tethering of leukocytes through the interaction of the selectin family and their ligands, and that the ICAM-1-LFA-1 pathway is not involved in this step. The lack of improvement in bile production with antibodies to the selectin family and their ligands strongly suggests that other mechanisms participate in the deterioration of hepatic function.

Adenosine↗
PubMed1996

Protective effects of antithrombin III supplementation on warm ischemia and reperfusion injury in rat liver.

The effect of antithrombin III (AT III) supplementation on energy status, microcirculation, cytoprotection, and prostacyclin (PGI2) production during and after a period of warm ischemia of the rat liver was investigated. AT III supplementation (250 units/kg) stimulate prostaglandin I2 (PGI2) production from 1 hour after administration, with maximal production observed at 3 hours. Ischemia was induced by occluding the hepatoduodenal ligament for 30 minutes, and experiments were continued for 60 minutes after reperfusion. The rats received AT III (250 units/kg IC) 30 minutes before induction of liver ischemia (AT III group). In the AT III group, recovery of the beta-ATP/inorganic phosphate ratio measured by 31P nuclear magnetic resonance showed significant improvement (p < 0.01), and the recovery of tissue blood flow markedly improved (p < 0.01) compared to the saline-treated group (control group). Leakages of aspartame aminotransferase, alanine aminotransferase, and lactate dehydrogenase were mitigated in the AT III group (p < 0. 05). Ultrastructural alterations of sinusoidal endothelial cells were markedly reduced in the AT III group. The PGI2 level at the end of reperfusion was significantly elevated (p < 0.01) in the AT III group compared to the control group. The results of this study indicated that pretreatment with AT III significantly improved the energy status and microcirculation, as well as histologic damage, after liver ischemia and reperfusion. One of the fundamental effects of AT III might be mediated through the production of prostacyclin.

6-Ketoprostaglandin F1 alpha↗
PubMed1996

Delivery of human fibroblast growth factor-1 gene to brain by modified rat brain endothelial cells.

Fibroblast growth factor (FGF) is an endothelial cell mitogen and serves as a mitogen and/or differentiating factor that can be neuroprotective for other cell types within the CNS. We established brain microvascular endothelial cell lines that secrete FGF-1 with the ultimate goal of examining their usefulness as a cellular platform for FGF gene delivery to brain. A chimeric gene consisting of the secretory sequence of FGF-4 linked at the 5' end of human FGF-1 (sp-hst/KS3:FGF-1) was transfected into rat microvascular endothelial cells previously altered to express the lacZ reporter gene (RBEZ), and numerous clones were found to secrete FGF-1 (RBEZ-FGF). Immunoblotting of conditioned medium demonstrated an 18-kDa protein corresponding to FGF-1. Conditioned medium from RBEZ-FGF cells enhanced [3H]thymidine incorporation in BALB/c3T3 fibroblasts by up to sevenfold when compared with conditioned medium of control cell lines, corresponding to as much as 110 ng of active FGF-1/mg of cell protein/24 h. RBEZ-FGF cell lines remained contact-inhibited and proliferated independent of exogenous endothelial mitogens, in contrast to control lines that are mitogen-dependent. Incubation of PC12 cells with RBEZ-FGF cells or their conditioned medium induced neurite outgrowth by PC12 cells. RBEZ-FGF cells survived following implantation to neonatal and adult rat caudate-putamen for at least 21 days based on 5-bromo-4-chloro-3-indolyl beta-D-galactopyranoside (X-gal) histochemistry, and FGF-1 gene expression by these cells in vivo was demonstrated by in situ hybridization and reverse transcriptase-PCR. These findings suggest that endothelial cells may be useful for FGF gene delivery to the CNS.

Animals↗
PubMed1996

Does the redox state of cytochrome aa3 reflect brain energy level during hypoxia? Simultaneous measurements by near infrared spectrophotometry and 31P nuclear magnetic resonance spectroscopy.

We studied cerebral oxygen metabolism during hypoxia to demonstrate whether the redox state of cytochrome aa3 (cyt.aa3), as measured by near infrared spectrophotometry (NIRS), reflects brain energy level. Rats (n = 6) subjected to hypoxia were simultaneously monitored by NIRS and 31P nuclear magnetic resonance spectroscopy (NMRS). Brain function was evaluated using the electroencephalogram (EEG). After a reduction of the fraction of inspired oxygen FIO2 from 0.21 to 0.15, we observed a significant increase in reduced cyt.aa3 (from 16.5% +/- 2.1% to 41.2% +/- 2.8%; P < 0.01), without significant changes in phosphocreatine (PCr) and beta-adenosine triphosphate (beta-ATP) levels. The PCr decreased significantly at a FIO2 of 0.10 (53.8% +/- 6.4% as compared with 97.7% +/- 10.9% at a FIO2 of 0.21; P < 0.05), and reached a minimum at a FIO2 of 0.04. beta-ATP did not change significantly at a FIO2 of 0.10 or 0.08. With a FIO2 of less than 0.08, cyt.aa3 was almost totally reduced. EEG activity slowed at a FIO2 of 0.08 and became isoelectric at 0.04. Significant correlations were found between the levels of cyt.aa3 and PCr (P < 0.001, r = 0.83) as well as between cyt.aa3 and beta-ATP (P < 0.001, r = 0.73) by using the overall values at FIO2 levels from 0 to 1.0. However, no significant correlations were observed among these variables when the FIO2 was less than 0.10. These findings suggest that the increase in reduced cyt.aa3 reflects brain energy depletion; however, the redox state of cyt.aa3 will not indicate brain energy depletion during extreme hypoxia because cyt.aa3 is reduced totally during hypoxia insufficient to deplete intracellular ATP.

Adenosine Triphosphate↗
PubMed1996

Detection of Cryptococcus neoformans gene in patients with pulmonary cryptococcosis.

Pulmonary cryptococcosis was diagnosed by nested PCR. Extraction of DNA was performed by mechanical destruction of the capsules of Cryptococcus neoformans by the glass bead technique. Nested PCR was positive for 4 of 5 culture-positive specimens but negative for 1 culture-positive specimen, 10 culture-negative specimens, and 1 specimen with undetermined culture results.

Base Sequence↗
PubMed1996

Enolase antigen, mannan antigen, Cand-Tec antigen, and beta-glucan in patients with candidemia.

We compared the specificities and sensitivities of four tests used for the serodiagnosis of candidemia in 39 patients with candidemia, including 10 patients with superficial Candida colonization, 10 patients with deep mycosis, and 20 healthy subjects. The results obtained by the dot immunoblotting assay for detecting the enolase antigen (48 kDa) were compared with those of assays for detecting mannan antigen, heat-labile antigen (a threshold titer of four times), and beta-glucan (> or = 60 pg/ml). Enolase antigen was detected in 28 (71.8%) patients with candidemia, while 30 (76.9%), 10 (25.6%), and 27 (84.4%) patients were positive for the heat-labile antigen by the Cand-Tec assay, the mannan antigen by the Pastorex Candida assay, and beta-glucan by the limulus test, respectively. Ten patients with superficial Candida colonization, 5 patients with invasive pulmonary aspergillosis, 5 patients with cryptococcosis, and 20 healthy subjects were negative for both enolase antigen and mannan antigen. Two patients with superficial Candida colonization, one patient with invasive pulmonary aspergillosis, and two patients with cryptococcosis were positive by the Cand-Tec assay. The beta-glucan concentration was more than 60 pg/ml in all patients with invasive pulmonary aspergillosis; however, it was less than 10 pg/ml in all patients with cryptococcosis. The specificity of enolase antigen in the serodiagnosis of candidemia was 100%, but the sensitivity was 71.8%. The specificity and sensitivity of Cand-Tec, the assay for mannan antigen, and the assay for beta-glucan were 76.9 and 87.5%, 25.6 and 100%, and 84.4 and 87.5%, respectively. Our results demonstrated that antigen detection tests are useful for the diagnosis of candidemia; however, none is satisfactory for the serodiagnosis of candidemia. We suggest that a combination of two assays may increase the accuracy of diagnosis of candidiasis.

Adult↗
PubMed1995

Comparison of warm and cold ischemia of the canine small intestine.

Warm and cold ischemia-reperfusion injuries to canine small intestine was compared. In the warm ischemic model, the superior mesenteric artery of mongrel dogs was clamped for 2 h and then released (group A). As a cold ischemia model, canine small intestines were harvested with cold lactated Ringer solution, preserved for 24 h in cold LR solution and then autotransplanted (group B). After ischemia and during reperfusion, activities of maltase (MAL), myeloperoxides (MPO), xanthine dehydrogenase (XD) and xanthine oxidase (XO) were measured as well as hypoxanthine (HX) concentration. MAL activities were not changed during warm or cold ischemia, whereas it was remarkably decreased after revascularization in both the groups. Neutrophil infiltration after reperfusion was shown by the increase of MPO activities to 8 and 1.5 U/mg protein in groups A and B respectively from a normal value of 0.35 U/mg protein. During warm ischemia, %XO (XO/XD + XO) was increased from 18.4 to 84.9% for 2 h. In contrast, %XO was not changed for 24 h of cold ischemia. Tissue accumulation of HX was increased 2.8 times from a normal value of 1.06, 2 h after warm ischemia, but there was almost neither accumulation of HX nor the conversion of XD to XO in 24 h cold ischemia. It was observed that warm and cold ischemia caused similar injury after reperfusion in spite of the striking difference in the conversion of XD to XO and accumulation of HX. Thus, it is suggested that the XO system is not always necessary for ischemia-reperfusion injury.

Animals↗
PubMed1995

Interactions of dopaminergic and GABAergic neurotransmission: impact of 6-hydroxydopamine lesions into the substantia nigra of rats.

We have evaluated (a) the effects of dopamine (DA) denervation on gamma-aminobutyric acid (GABA) turnover in terms of in vivo rate of GABA synthesis; (b) effects of DA D1 and D2 receptor agonists and antagonists on the in vivo GABA synthesis rate; and (c) the effects of GABAA and GABAB receptor agonists and antagonists on the intracellular accumulation of cAMP in the ipsi- and contralateral striatum and substantia nigra of rats after unilateral 6-hydroxydopamine-induced lesions of the nigrostriatal DA system (DA depletion > 90%). We observed that the in vivo rate of GABA synthesis remained unaffected when the DA levels were depleted by 95% and 50% in the ipsilateral striatum and substantia nigra, respectively, compared with the contralateral intact side. Basal cAMP levels were increased significantly (92%) in the ipsilateral striatum only, compared with the contralateral intact side. The DA D2 agonist quinpirole (1.0 mg/kg) significantly decreased the rate of GABA formation in the ipsi- and contralateral striatum and substantia nigra. In contrast, the D2 antagonist (+/-)-sulpiride (25.0 mg/kg) augmented the rate of GABA formation in the DA-denervated and intact striatum and substantia nigra. On the other hand, D1 agonist SKF 38393 (10.0 mg/kg) did not affect the GABA synthesis rate. The in vivo rate of GABA synthesis also remained unaffected after administration of D1 antagonist SCH 23390 (1.0 mg/kg) except in the ipsilateral striatum.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Development and evaluation of co-agglutination test to detect rotavirus antigens in stools of patients with diarrhoea.

Rotavirus is the most common cause of acute diarrhoea in infants and children in both the developed and developing countries including Bangladesh. Information about rotavirus diarrhoea in Bangladesh is insufficient primarily due to the lack of diagnostic facilities due to the high cost of reagents and equipment and lack of skilled personnel. A simple, suitable and less costly technique of co-agglutination test using protein-A secreting staphylococci was developed and evaluated against a commercially available ELISA kit to detect rotavirus antigen in stools of patients with diarrhoea. Staphylococcus cowan strain 1 was grown and coated with rabbit antisera raised against RV5 and SA11 rotavirus strains. The antibody-coated staphylococci were agglutinated specifically by rotavirus present in faecal samples within one or two minutes. A total of 1332 stool specimens were tested by co-agglutination and ELISA, of which 210 (15.77%) were positive by ELISA and 276 (20.72%) by co-agglutination test. Compared to ELISA, sensitivity of co-agglutination test was 76.19%, specificity 89.66% and predictive values of a positive and a negative test were 57.97% and 95.26% respectively. The results indicate that the co-agglutination test is a simple and suitable technique for rapid screening of rotavirus infection which could be adopted in clinical practice.

Agglutination Tests↗