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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
PubMed1999

In vitro and in vivo activities of NS-718, a new lipid nanosphere incorporating amphotericin B, against Aspergillus fumigatus.

We evaluated the in vitro and in vivo potencies of a new lipid nanosphere that incorporates amphotericin B (AmB), NS-718, against Aspergillus fumigatus. The in vitro activity of NS-718 (the MIC at which 90% of strains are inhibited [MIC90], 0.25 microgram/ml) against 18 isolates of A. fumigatus was similar to that of deoxycholate AmB (D-AmB; Fungizone; MIC90, 0.25 microgram/ml), but NS-718 was more potent than liposomal AmB (L-AmB; AmBi-some; MIC90, 1.0 microgram/ml). The in vivo efficacy of NS-718 in a rat model of invasive pulmonary aspergillosis was compared with those of D-AmB and L-AmB. A low dose (1 mg/kg of body weight) of L-AmB was ineffective (survival rate, 0%), although equivalent doses of D-AmB and NS-718 were more effective (survival rate, 17%). However, a higher dose of NS-718 (3 mg/kg) was more effective (survival rate, 100%) than equivalent doses of D-AmB and L-AmB (survival rate, 0%). To explain these differences, pharmacokinetic studies showed higher concentrations of AmB in the plasma of rats treated with NS-718 than in the plasma of those treated with D-AmB. Our results suggest that NS-718, a new preparation of AmB, is a promising antifungal agent with activity against pulmonary aspergillosis.

Amphotericin B↗
PubMed1998

Bleomycin-induced pulmonary fibrosis in rat is associated with increased expression of collagen-binding heat shock protein (HSP) 47.

Increased accumulation of collagens in extracellular matrix (ECM) is mainly responsible for bleomycin-induced pulmonary fibrosis in rats. This study was designed to assess whether increased collagen accumulation in bleomycin-induced pulmonary fibrosis is associated with heat shock protein (HSP) 47, a molecular chaperone for collagen biosynthesis. We investigated the expression of type I and type III collagens and HSP47 in bleomycin-induced pulmonary fibrosis. Fifteen male Wistar rats were divided into two groups; group I: bleomycin-induced pulmonary fibrosis; group II: PBS-treated age-matched control rats. Pulmonary fibrosis was induced by injecting a single dose of bleomycin sulphate (5 U/kg body weight) intratracheally. Three bleomycin-treated rats and two age-matched control rats were sacrificed at the end of each of the 1st, 2nd and 4th weeks of the experiment. In bleomycin-treated rats, histological examination revealed pulmonary fibrosis, which increased with time. Increased type I and type III collagen desposition was observed in the lungs of all the bleomycin-treated rats. Weak immunostaining of HSP47 was noted in the control lungs. In contrast, strong immunostaining for HSP47 was seen in all the bleomycin-treated fibrotic lungs. In addition, increased numbers of phenotypically altered myofibroblasts (alpha-smooth muscle actin immunopositive) and fibroblast (vimentin immunopositive) were seen in bleomycin-treated lungs and found to express HSP47. Parallel increase of collagens and their molecular chaperone HSP47 expression was found in the bleomycin-treated lungs, and their co-localization could be detected by double immunostaining. Overexpression of HSP47 may play a significant part in the excessive assembly of collagens and could contribute in this way to the fibrosis found in bleomycin-treated rat lungs.

Animals↗
PubMed1998

The effects of intraportal administration of prostaglandin E1 on liver ischemia and hepatectomy in rats.

The effects of intraportal administration of prostaglandin E1 (PGE1) on portal venous flow, hepatic arterial flow, peripheral tissue blood flow, and systemic arterial flow before and after 60 min total liver ischemia followed by 70% partial hepatectomy in rats were investigated. Total liver ischemia was induced by occluding the hepatoduodenal ligament for 60 min. PGE1 at a dose of 0.5 microg/kg/min was infused intraportally for 15 min before inducing hepatic ischemia (preischemic period) and for 60 min after ischemia (postischemic reperfusion period) in the treatment group. Normal saline was infused in the control group. Seventy percent partial hepatectomy was performed during ischemia. Serum biochemical analysis and liver tissue histology were carried out 1, 3, and 24 h, and 1 and 24 h after reperfusion respectively. One-week survival of the PGE1 group was improved to 70% compared to that of the control group of 30%. Postischemia reperfusion values of portal and peripheral tissue blood flows in the PGE1 group were 6.33 +/- 0.600 ml/min and 27.2 +/- 23.5 (arbitrary), and were significantly different from those of the control group of 4.34 +/- 0.400 ml/min and 23.5 +/- 5.54 (arbitrary), respectively. There was no significant difference in hepatic arterial flow between the two groups. Serum alkaline phosphatase decreased significantly in the prostaglandin group. Histological examination revealed a significant portal venous congestion in the control group 1 and 24 h after reperfusion. The extent of the sinusoidal congestion was also severe in the control group 24 h after reperfusion. It was concluded that PGE1 has a protective effect against liver damage when the liver was injured by warm ischemia and reperfusion followed by partial resection.

Alprostadil↗
PubMed1998

Increasing frequency of mecillinam-resistant shigella isolates in urban Dhaka and rural Matlab, Bangladesh: a 6 year observation.

A total of 14,915 shigella isolates obtained in 1991-1996 from patients attending the Dhaka (urban) and Matlab (rural) treatment centres of the International Centre for Diarrhoeal Disease Research, Bangladesh were examined for susceptibility to ampicillin, co-trimoxazole, nalidixic acid, mecillinam and ciprofloxacin by a disc diffusion method. There were no ciprofloxacin-resistant shigella isolates. The prevalence of resistance to ampicillin, co-trimoxazole and nalldixic acid varied between isolates. It increased to similar degrees in isolates from both Matlab and Dhaka. However, resistance to mecillinam was more prevalent among isolates from Matlab than from Dhaka. The increase in mecillinam-resistant shigellae in the community may have grave implications for the empirical treatment of shigellosis in Bangladesh and other developing countries.

Amdinocillin↗
PubMed1998

Synergic effects of tactolimus and azole antifungal agents against azole-resistant Candida albican strains.

We investigated the effects of combining tacrolimus and azole antifungal agents in azole-resistant strains of Candida albicans by comparing the accumulation of [3H]itraconazole. The CDR1-expressing resistant strain C26 accumulated less itraconazole than the CaMDR-expressing resistant strain C40 or the azole-sensitive strain B2630. A CDR1-expressing Saccharomyces cerevisiae mutant, DSY415, showed a marked reduction in the accumulation of both fluconazole and itraconazole. A CaMDR-expressing S. cerevisiae mutant, DSY416, also showed lower accumulation of fluconazole, but not of itraconazole. The addition of sodium azide, an electron-transport chain inhibitor, increased the intracellular accumulation of itraconazole only in the C26 strain, and not in the C40 or B2630 strains. Addition of tacrolimus, an inhibitor of multidrug resistance proteins, resulted in the highest increase in itraconazole accumulation in the C26 strain. The combination of itraconazole and tacrolimus was synergic in azole-resistant C. albicans strains. In the C26 strain, the MIC of itraconazole decreased from >8 to 0.5 mg/L when combined with tacrolimus. Our results showed that two multidrug resistance phenotypes (encoded by the CDR1 and CaMDR genes) in C. albicans have different substrate specificity for azole antifungal agents and that a combination of tacrolimus and azole antifungal agents is effective against azole-resistant strains of C. albicans.

AIDS-Related Opportunistic Infections↗
PubMed1998

Preliminary report of a randomized, double-blind placebo-controlled trial of a Chinese herbal medicine preparation CH-100 in the treatment of chronic hepatitis C.

The treatment of chronic hepatitis C is relatively unsatisfactory and many patients have turned to unproven alternative medicines to modify the course of their illness. We report a study of a Chinese herbal medicine preparation CH-100 in the management of chronic hepatitis C. Patients with documented chronic hepatitis C were randomly allocated to receive active herbal or placebo tablets (five tablets thrice daily). Patients were followed monthly and evaluated by a Western and a traditional Chinese medical practitioner. Therapy was monitored by measurement of liver function tests, creatinine and full blood count on a monthly basis. Twenty patients in each group were well matched for age, sex, duration of illness, previous interferon therapy and alcohol intake. Active Chinese herbal medication was associated with a significant reduction in alanine aminotransferase (ALT) levels over the 6 month study period (P < 0.03). No patient cleared the virus but four normalized their ALT on treatment. Appropriately prescribed Chinese herbal medicine may have a role in the management of chronic hepatitis C and further controlled studies are indicated.

Adolescent↗
PubMed1998

Efficacy of NS-718, a novel lipid nanosphere-encapsulated amphotericin B, against Cryptococcus neoformans.

In vitro and in vivo efficacies of NS-718, a lipid nanosphere-encapsulated amphotericin B (AMPH-B), have been studied. Of the tested AMPH-B formulations, NS-718 had the lowest MIC for Cryptococcus neoformans. In a murine model, low-dose therapy (0.8 mg/kg of body weight) with NS-718 showed higher efficacy than that with AmBisome. High-dose therapy (2.0 mg/kg) with NS-718 was much more effective than those with Fungizone and AmBisome. In mice treated with a high dose of NS-718, only a few yeast cells had grown in lung by 7 days after inoculation. A pharmacokinetic study showed higher concentrations of AMPH-B in lung following administration of NS-718 than after administration of AmBisome. Our results indicated that NS-718, a new AMPH-B formulation, is a promising antifungal agent for treatment of pulmonary cryptococcosis and could be the most effective antifungal agent against C. neoformans infections.

Amphotericin B↗
PubMed1998

Detection of Mycobacterium tuberculosis in preserved tuberculous lymph nodes by polymerase chain reaction.

We evaluated the usefulness of three types of polymerase chain reaction (PCR) targeting 16S rRNA, protein antigen b and IS6110 in detecting Mycobacterium tuberculosis in preserved tuberculous lymph nodes. The detection limit of all PCR methods was 100 colony forming unit (CFU) of M. tuberculosis in tissue. The test samples included eight paraffin-embedded tuberculous lymph nodes containing microscopical epithelioid cell granuloma with caseous necrosis and Langhans giant cells. Although acid-fast stained organisms in lymph node tissue were not detected in any sample, all three types of PCR tests were positive in four of eight lymph nodes. Our results suggest that PCR is not only a rapid and sensitive diagnostic method for tuberculous lymphadenitis, but also clinically significant in retrospective study for detecting M. tuberculosis even in some preserved lymph node tissues without evidence of acid-fast stained organisms.

Antigens, Bacterial↗
PubMed1998

Human FGF-1 gene delivery protects against quinolinate-induced striatal and hippocampal injury in neonatal rats.

Fibroblast growth factors (FGFs) are cell mitogens and differentiating factors with neuroprotective properties in the CNS. We have already shown that endothelial cells genetically engineered to secrete human FGF-1 (RBEZ-FGF) survive implantation to neonatal rat brain (Johnston et al. (1996) J. Neurochem. 67, 1643-1652]. In this study, the effects of cell-based FGF-1 gene delivery on quinolinate-induced neurotoxicity in the developing rat brain were examined. Control endothelial cells (RBE4), and RBEZ-FGF cells were implanted into right striatum at post-natal day (PND) 7. On PND 10, quinolinate (150 nmol), an endogenous N-methyl-d-aspartate (NMDA) receptor agonist, or vehicle alone was injected into striatum ipsilateral to cell implantation. Injury was quantified in coronal sections obtained from PND 17 animals by comparing striatal and hippocampal volumes ipsilateral and contralateral to the site of quinolinate injection. Human FGF-1 specific transgene expression in vivo was shown by Northern blot and RT-PCR up to 14 days after cell implantation in control animals, and up to 4 days after quinolinate exposure. Quinolinate reduced the size of ipsilateral striatum by 37% and hippocampus by 38% in animals preimplanted with control endothelial cells. In contrast, quinolinate reduced the size of striatum by only 14% and had no effect on hippocampal size in animals preimplanted with RBEZ-FGF cells. Thus, FGF-1 gene delivery protected the developing striatum and hippocampus from quinolinate-induced volume loss by 62% and 100%, respectively. Intrastriatal quinolinate resulted in a significant decrease in density of NOS+ CA3 hippocampal neurons (-38%) without affecting the density of NOS+ neurons in hippocampal regions CA1, dentate gyrus or striatum. This response of CA3 NOS+ neurons appeared to be only partially reversed by FGF-1 gene delivery. Our results show that intracerebral FGF-1 gene expression within the developing brain can protect striatum and hippocampus from quinolinate-mediated injury.

Animals↗
PubMed1998

Cerebral malaria--a study of 104 cases.

One hundred and four adult cases of cerebral malaria (73 male, 31 female) were studied between July 1995 to June 1996 in Chittagong Medical College Hospital. Diagnosis of cerebral malaria was based on unrousable coma or any neurological manifestation in a febrile patient with asexual Plasmodium falciparum in blood film. Intermittent fever (83%), vomiting (80%), headache (75%), convulsion (60%) and history of travel or residence in malaria endemic area were important features noted in patients with cerebral malaria. Most of the patients (69%) were admitted within 25 to 48 hours following unconsciousness. The factors are more common in cases with high mortality with diastolic blood pressure (DBP) below 60 mm of Hg, anaemia, persistence of Glasgow Coma Score below 5 on day 2, high parasite count at presentation, proteinuria and high level of serum urea. Out of 104 cases of cerebral malaria 66 patients (63.5%) recovered without sequelae, 34 patients (32.7%) died and 4 patients (3.8%) recovered with some residual sequelae. Establishment of intensive care unit in tertiary level hospitals is necessary to take appropriate measure for severe cerebral malaria cases for reduction of mortality.

Adult↗
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↗