[The future of antifungal agents. Non azole antifungal agents]

We investigated the efficacy of non-azole antifungal agents. Long circulating immunoliposomal amphotericin B was potent in murine invasive pulmonary aspergillosis. The concentration of AMPH-B was still high in the lung after 6 hours of 34A-PEG-liposomal AMPH-B. Lipid nanosphere amphotericin B (NS-718) showed efficacy against pulmonary aspergillosis in rats and pulmonary cryptococcosis in mice. The renal toxicity of NS-718 was estimated to be lower than that of AMPH-B from the results of the toxicity study in the rat infusion model. FK 463, a novel (1,3)-beta-D-glucan synthase inhibitor, showed efficacy against azole-resistant Candida albicans in murine experimental disseminated candidiasis. FK463 could be a promising drug and the therapy of choice for azole resistant C. albicans infection.

Experimental study of the effect of intraportal prostaglandin E1 on hepatic blood flow during reperfusion after ischaemia and hepatectomy

BACKGROUND

Prostaglandin E1 (PGE1) has protective effects experimentally and clinically in individual models of hepatic ischaemia-reperfusion injury and of partial hepatectomy. The present study investigated the effects of intraportal administration of PGE1 on hepatic blood flow, systemic arterial pressure and long-term animal survival after 60 min of total liver ischaemia followed by 70 per cent partial hepatectomy in rats.

METHODS

Total liver ischaemia was induced by occluding the hepatoduodenal ligament for 60 min. PGE1 0.5 microg per kg per min was infused intraportally for 15 min before inducing ischaemia and for 120 min after ischaemia in the treatment group. Normal saline was infused in the control group. During ischaemia 70 per cent partial hepatectomy was performed. Portal venous flow (PVF), peripheral tissue blood flow (PTBF) and hepatic artery flow were measured before and after ischaemia. Serum biochemical analysis was carried out at 1, 3 and 24 h, and 7 and 14 days; and liver histology at 1 and 24 h, and 7 days after reperfusion. Survival was followed for 1 year.

RESULTS

Intraportal infusion of PGE1 significantly improved PVF and PTBF without affecting the systemic arterial pressure. Long-term survival was significantly higher in the PGE1 group. Serum aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase levels decreased significantly, and 2-h bile flow was significantly improved, in the PGE1 group. Histological examination revealed significant portal venous congestion, sinusoidal congestion, fatty degeneration and tissue necrosis 24 h and 7 days after reperfusion in the control group.

CONCLUSION

PGE1 has a protective effect against liver damage when the liver is injured by warm ischaemia and reperfusion followed by partial resection.

Unguided percutaneous transthoracic fine needle aspiration cytology in the diagnosis of the peripheral lung lesions

Percutaneous transthoracic fine needle aspiration cytology (PTFNAC) of lung was done in 614 cases at the department of Pathology of Institute of Diseases of Chest and Hospital (IDCH), Dhaka, during the period from July 1994 to July 1996. A definite diagnosis was possible in 417 cases (78.83%). More than half (57.65%) of the cases were proved to have malignant diseases. PTFNAC detected malignant lesion in these patients for the first time as because no other investigation was able to establish the diagnosis. Diagnostic accuracy was 74%. Only 12 (1.95%) patients developed pneumothorax and mild haemoptysis occurred in 23 (3.74%) patients. So unguided PTFNAC is a simple, time saving, safe and inexpensive method of diagnosis of peripheral lung lesions.

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.

Heat shock protein 70 (hsp70) as a major target of the antibody response in patients with pulmonary cryptococcosis

Cryptococcus neoformans causes infection in individuals with defective T cell function, such as AIDS, as well as without underlying disease. It has been suggested that humoral as well as cellular immunity might play an important role in the immune response to C. neoformans infection. We have recently shown, using immunoblotting, that the 70-kD hsp family of C. neoformans was the major target molecule of the humoral response in murine pulmonary cryptococcosis. In this study we also used immunoblotting to define the antibody responses in the sera of 24 patients with pulmonary cryptococcosis: 21 proven and three suspected diagnoses. Anti-C. neoformans hsp70 antibody was detected in 16 of 24 (66.7%) patients with pulmonary cryptococcosis. Fourteen of 17 (82.3%) patients with high antigen titres (> or = 1:8) and two of seven (28.6%) patients with low titres (< or = 1:4) had detectable levels of anti-hsp70 antibody. Sera from patients positive for anti-hsp70 antibody showed high titres in the Eiken latex agglutination test for the detection of serum cryptococcal antigen. Our results indicate that the 70-kD hsp family from C. neoformans appears to be a major target molecule of the humoral response, not only in murine pulmonary cryptococcosis, but also in human patients with pulmonary cryptococcosis.

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.

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.

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.

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.

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.

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.

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.

Karyotypic analysis of N-banded chromosomes of diploid alfalfa: Medicago sativa ssp. caerulea and ssp. falcata and their hybrid

Chromosomes of two diploid (2n = 2x = 16) subspecies of Medicago sativa, ssp. caerulea and ssp. falcata, and their hybrid were studied using an N-banding technique. This study was undertaken to develop an N-banded karyotype of ssp. caerulea and ssp. falcata, and determine if the same technique could be used to identify parental chromosomes in hybrids. The chromosomes of ssp. falcata have only centromeric N bands and thus individual chromosomes could not be identified. However, chromosome-specific bands were observed in ssp. caerulea enabling the identification of each of the eight pairs of chromosomes and the development of an idiogram. All chromosomes have a centromeric band and a telomeric band in the short arm. All of the chromosomes, except chromosomes 7 and 8, have interstitial bands in their long arms and chromosome 5 has two faint interstitial bands in its long arm. The satellited chromosome is easily distinguished due to the secondary constriction and characteristic band at the nucleolar organizer region. The differences in banding patterns between these subspecies makes it possible to distinguish chromosomes from each other in their hybrids. This is the first report of the use of N banding to identify the diploid chromosomes of M. sativa ssp. caerulea and ssp. falcata.

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.

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.

Abundance and Distribution of Bacillus thuringiensis in the Agricultural Soil of Bangladesh

Bacillus thuringiensis is distributed ubiquitously in the agricultural soil of Bangladesh. Simple correlation and regression analyses showed that the soil sand percentage and the available copper levels had significant negative and positive contributions, respectively, to the abundance and distribution of B. thuringiensis in the agricultural soil. Among the isolates, only 2.5% of strains showed larvicidal activity against the mosquito Culex quinquefasciatus. The larvicidal potency LD50 varied from 3.5 x 10(3) to 9.5 x 10(7) spores per milliliter among the isolates. Copyright 1997 Academic Press. Copyright 1997 Academic Press

Karyotypic analysis of C-banded chromosomes of diploid alfalfa: Medicago sativa ssp. caerulea and ssp. falcata and their hybrid

Chromosomes of two diploid (2n = 2x = 16) subspecies of Medicago sativa ssp. caerulea and ssp. falcata and their hybrid were studied by C-banding. This study was undertaken to improve the C-banding technique for alfalfa chromosomes, develop a C-banded karyotype of the ssp. caerulea and ssp. falcata, and determine if the same C-banding technique could be used to identify parental chromosomes in hybrids. The chromosomes of ssp. falcata have only centromeric bands and thus individual chromosomes could not be identified. One accession of ssp. falcata displayed an interstitial band in the middle of the long arm on the satellite chromosome. However, chromosome-specific bands were observed in ssp. caerulea enabling the identification of each of the eight pairs of chromosomes and the development of a idiogram. All chromosomes had centromeric bands and a terminal band in the short arm except the satellite chromosome (chromosome 8). Interstitial bands were also observed in the short arms, with the exception of chromosome 7. Chromosomes 1, 2, 3, and 8 each had one prominent interstitial band in their long arm. The satellited chromosome is easy to identify because of the presence of the secondary constriction, two bands located on either side of the nucleolar organizer region, and a large terminal band on its long arm. The differences in banding patterns between these subspecies allowed the identification of parental chromosomes in hybrid cells.

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.

Evaluation of indicators of tissue hypoxia during progressive hemorrhage and blood retransfusion

To establish whether the indicators of oxygen metabolism reflects the improvement in tissue oxygenation during therapy, twelve rabbits subjected to progressive hemorrhage followed by retransfusion were studied. The changes in oxygen delivery (DO2), oxygen consumption (QO2), oxygen extraction ratio (O2ER), arterial lactate concentration, venous-arterial difference in PcO2 (v-aDPcO2) and arterio-venous difference in pH (a-vDpH) were analyzed during two phases (above and below) the critical DO2 with the regression coefficient (slope). The main findings during the transfusion were: a) the slope, when compared during the two phases was not significantly different for O2ER, v-aDPcO2 or a-vDpH, while during hemorrhage each variable showed a significantly different slope, b) in the phase below the critical DO2, the slope was significantly less steep than that during hemorrhage for lactate and v-aDPcO2, c) in the phase above the critical DO2, lactate alone had significantly steeper slope than that during hemorrhage. In conclusion, it is suggested that the changes in QO2 best reflect the recovery from tissue hypoxia.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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)

Age-related changes in tetrahydrobiopterin and GTP-cyclohydrolase activity in the brain and adrenal gland of rats

In the present study, we observed that tetrahydrobiopterin (BH4) levels were decreased significantly in the striatum, substantia nigra, frontal cortex, hypothalamus, and cerebellum of 25-month-old and in the cerebellum only in case of 18-month-old rats as compared to 4-month-old rats. In contrast, BH4 levels in adrenal glands of 25-month-old rats were increased significantly. Kinetic analysis of GTP-cyclohydrolase revealed a decrease in the apparent Km along with an increase in Vmax value in the adrenal of 25-month-old rats compared to 4-month-old rats. Whereas, in cerebellum we observed that the apparent Km of the high affinity form of the enzyme was increased and a decrease in the Vmax value of the low affinity form only in case of 25-month-old rats compared to the young animals. These alterations in the BH4 levels and its synthesizing enzyme kinetics in specific brain areas and adrenal glands of aged rats are consistent with the reported changes in the catecholamine function in central and peripheral nervous system with aging.

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.

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.

Basic study on hepatic resection under partial perfusion cooling

To improve liver quality after reperfusion following partial hepatectomy under total or partial cooling of the liver (HPC), a new perfusion solution containing 100 mM L-histidine (KM solution) was developed. The livers of Lewis rats were removed and perfused for 2 hours at 20 degrees C with lactated Ringer's (LR) solution (group A) or the KM solution (group B). They were reperfused with rat blood at 37 degrees C at a perfusion pressure of 5 cmH2O while monitoring the portal and peripheral tissue blood flows. At the end of reperfusion, bile production, lactate dehydrogenase (LDH) secretion, and tissue adenosine triphosphate (ATP) was measured. Recovery of portal and peripheral tissue blood flows of the group B livers after reperfusion were significantly better than those of group A. Viability of the group B livers, assessed by bile production, tissue ATP value, and LDH release, was preserved better than that of group A livers. In situ total liver perfusion with LR (group C) and KM (group D) solutions for 1 hour at 20 degrees C followed by partial hepatectomy of the left lateral lobe was performed. The 1-week survivals of the group C and D rats were 25% and 100%, respectively (p < 0.05). It was concluded that KM solution is suitable for HPC.

Dopaminergic functional supersensitivity: effects of chronic L-dopa and carbidopa treatment in an animal model of Parkinson's disease

We have evaluated the effects of L-Dopa and carbidopa treatment (30 days) on dopamine (DA) turnover, intracellular cyclic AMP (cAMP) accumulation and tetrahydrobiopterin levels in the nigrostriatal pathway of rats with a unilateral 6-OHDA lesions (greater than 90% lesions). We observed significant increase in the 3,4-dihydroxy-phenylacetic acid/DA and homovanillic acid/DA ratios, and in basal cAMP levels (92%) in the ipsilateral striatum, but not in the substantia nigra when compared to the contralateral intact hemisphere. After L-dopa/carbidopa treatment, the increased 3,4-dihydroxy-phenylacetic acid/DA, homovanillic acid/DA ratios and the elevated levels of cAMP in the ipsilateral striatum were reduced significantly and returned to the control levels of contralateral non-lesioned side. Tetrahydrobiopterin levels obtained on both sides remained unaffected after treatment. The D1 agonist SKF 38393 (10 microM) increased cAMP accumulation significantly in striatal slices from the lesioned and intact hemispheres in both vehicle and treatment group, which were completely inhibited by the D1 antagonist SCH 23390 (10 microM). In contrast, the ability of SKF 38393 to enhance the cAMP accumulation was blocked by the D2 agonist quinpirole (10 microM) in striatal slices from the intact hemisphere, but not from the lesioned side. In substantia nigra, no significant differences in cAMP accumulation were observed. Our data suggests that chronic L-dopa/carbidopa treatment reverses the increased dopaminergic activity and D1 receptor functional supersensitivity seen after 6-hydroxydopamine lesions, and indicates a D1 receptor-mediated action of L-dopa.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative effects of electroconvulsive shock and haloperidol on in vivo tyrosine hydroxylation and tetrahydrobiopterin in the brain of rats with 6-hydroxydopamine lesions

We have evaluated the effects of electroconvulsive shock (ECS) and haloperidol treatment on the in vivo tyrosine hydroxylation rate and the tetrahydrobiopterin levels in the nigrostriatal system of 6-OHDA-lesioned rats. The rate of DOPA accumulation was significantly decreased by 96% in the ipsilateral striatum and by 50% in substantia nigra of the 6-OHDA-lesioned rats compared to the control activity of contralateral non-lesioned striatum and substantia nigra. The loss of total biopterin was found to be 75% and 50% in the ipsilateral striatum and substantia nigra, respectively. Following administration of haloperidol, the rate of DOPA accumulation increased significantly in the striatum and substantia nigra on the lesioned side compared to that in the vehicle treatment group. Application of ECS also significantly increased the rate of DOPA accumulation in the ipsilateral striatum and substantia nigra compared to that obtained in the non-shocked rats. The biopterin levels in the nigrostriatal system of 6-OHDA-lesioned were elevated significantly in the striatum after haloperidol treatment; in contrast the biopterin levels were unchanged in response to ECS. Our results show that both haloperidol and ECS significantly enhanced the rate of in vivo tyrosine hydroxylation in the striatum and substantia nigra of rats with greater than 90% lesions. These results suggest that the nigrostriatal system, although up-regulated following 6-OHDA lesions, still maintains the potential for further up-regulation of dopaminergic function in response to haloperidol and ECS treatment.

Effects of electroconvulsive shock on tetrahydrobiopterin and GTP-cyclohydrolase activity in the brain and adrenal gland of the rat

The effects of a single and repeated electroconvulsive shock (ECS) (300 mA, 0.2 s) on tetrahydrobiopterin (BH4) levels and GTP-cyclohydrolase activity in the brain and adrenal glands of rats were examined. Twenty-four hours after the last ECS treatment (one/day for 7 days), biopterin levels were significantly elevated in the locus coeruleus, hippocampus, frontal cortex, hypothalamus, ventral tegmental area, and adrenal gland. There were no changes in biopterin levels after a single application of ECS. GTP-cyclohydrolase activity was significantly increased in the locus coeruleus, frontal cortex, hippocampus, hypothalamus, and adrenal gland 24 h after repeated ECS and remained elevated in certain tissues up to 8 days after the last treatment. Kinetic analysis of adrenal and locus coeruleus GTP-cyclohydrolase 1 day after 7 days of ECS showed significant changes in both Km and Vmax values. These data suggest that the long-term increases in BH4 levels and GTP-cyclohydrolase activity after repeated ECS may play a part in the mediation of the antidepressant effects of ECS.

Incidence of Aeromonas isolated from diarrhoeal children and study of some virulence factors in the isolates

Stool samples from 305 children with diarrhoea and equal number of age and sex matched non-diarrhoeal control children, less than 5 years of age, were examined during the period from Sept 1988 to April 1989. Aeromonas spp. were isolated from 37 (12.1%) diarrhoeal and 05 (1.6%) control cases. Out of 37 diarrhoeal isolates 13 (35.1%) were A. hydrophila, 19 (51.1%) A. sobria and 05 (13.5%) A. caviae. All the isolated strains were tested for haem agglutination property and haemolysin production. Seventeen diarrhoeal and 05 control isolates were tested for cytotoxin production in He La cell line and enterotoxin production in rat ileal loop model and suckling mouse model. Chinese hamster ovary cell (CHO) assay and Gm-1 ELISA methods were also employed. Cytotoxin production was found in 82.5% of diarrhoeal and 40% of control isolates. Haemagglutination was found in 62.1% of Aeromonas isolated from diarrhoeal children and 20% from control children. Enterotoxin production was detected in 58.8% diarrhoeal and none of the control isolates by either of the methods. Of the virulence factors enterotoxin production was found to correlate well with enteropathogenicity but haemolysin, cytotoxin and haemagglutinin did not.

Campylobacter jejuni bacteraemia in children with diarrhoea in Bangladesh: report of six cases

Campylobacter jejuni was isolated from blood cultures from 6 of 6,275 diarrhoeal children seeking treatment at the Clinical Research Centre of the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B) between April 1989 and December 1990. The clinical records of these 6 children were reviewed. All children were male; 5 were less than 1-year old and were severely malnourished. Five patients presented with watery diarrhoea and one with bloody diarrhoea. Two children died in the hospital. All strains of Campylobacter isolated from the 6 children were negative for cell invasive properties as tested by the Sereny test. Of the two strains tested for serum bactericidal activity, one strain was serum sensitive (growth inhibition), and the other resistant. The ability of C. jejuni to cause bacteraemia suggests that the organisms may be responsible for diarrhoeal diseases especially in young and malnourished children. An early attempt to detect Campylobacter and start effective antimicrobial therapy is indicated.

Antimicrobial resistance of Shigella isolates in Bangladesh, 1983-1990: increasing frequency of strains multiply resistant to ampicillin, trimethoprim-sulfamethoxazole, and nalidixic acid

The susceptibility to ampicillin and trimethoprim-sulfamethoxazole (TMP-SMZ) was determined for 15,824 isolates of Shigella obtained from patients attending a treatment center in Dhaka, Bangladesh, from 1983 through 1990 and for 520 isolates obtained during community surveys from 1988 through 1990. Susceptibility to nalidixic acid was determined for isolates obtained after 1985. In 1983 13% of isolates were resistant to ampicillin, 23.5% to TMP-SMZ, and 0.8% to both drugs. By 1990 51.2% of isolates obtained at the Diarrhea Treatment Centre were resistant to ampicillin, 47.7% to TMP-SMZ, and 40.5% to both drugs (for comparison with figures for 1983, P less than .001). Resistance to nalidixic acid increased from 0.8% in 1986 to 20.2% in 1990 (P less than .001). In 1990 71.5% of Shigella dysenteriae type 1 isolates were resistant to ampicillin, 68.5% to TMP-SMZ, 67.7% to both drugs, and 57.9% to nalidixic acid. The resistance pattern of isolates obtained during community surveillance was similar to that of Treatment Centre isolates. In Bangladesh ampicillin and TMP-SMZ are no longer useful for treatment of infection with any species of Shigella, and nalidixic acid is no longer useful for treatment of infections due to S. dysenteriae type 1.

Studies on virulence determinants of Plesiomonas shigelloides

Virulence determinants of nineteen strains of Plesiomonas shigelloides isolated from stool samples of diarrhoeal children were studied. Heat-labile toxin was detected in seven strains using rat ileal loop model and in none of the strains using Chinese hamster ovary cell assay system and by Enzyme-linked immunosorbent assay. Rat ileal loop model was used for the first time to assay toxin in P. shigelloides and is suggested to be a cheap and effective method of detecting labile toxin in the organism. Heat stable toxin, cytotoxin, hemolysin and hemagglutinin were not detected in the strains tested. Invasiveness could not be established by using HEp-2 cell assay system. The results of this study provide some experimental support for an etiological role for P. shigelloides in the production of diarrhoea.

Effect of duration of diarrhoea and predictive values of stool leucocytes and red blood cells in the isolation of different serogroups or serotypes of Shigella

Diarrhoeal stools from 11,358 patients were microscopically examined for the presence of white and red blood cells (WBC and RBC) and cultured for enteric pathogens. Of the 3895 patients who had Shigella as sole pathogens, 2681 (72.3%) showed the presence of both WBC and RBC and the remainder had only WBC (P less than 0.001). The presence of both WBC and RBC was as good a predictor of shigellosis as the presence of greater than 25 WBC per high power field (hpf) of the microscope with or without RBC. However, the best predictor of shigellosis (positive predictive value 85%, negative predictive value 83%) was the presence of greater than 25 WBC/hpf and the presence of RBC regardless of their number. More patients infected with S. dysenteriae 1, S. flexneri and S. boydii shed both WBC and RBC than those infected with S. sonnei, most of whom shed WBC only (P less than 0.001). A greater number of patients infected with S. dysenteriae 1 shed more WBC and RBC than those infected with S. flexneri (P less than 0.001). The same trend was found when patients infected with S. flexneri were compared with those infected with S. boydii (though the difference was not statistically significant) and when patients infected with S. boydii were compared with patients infected with S. sonnei (P less than 0.001). There was a progressive decline in the isolation rate of Shigella as the duration of dysentery, before stool culture, increased.