Biomedical subjects

M M Rahman

Publications and source records attributed to M M Rahman.

At least 37 records · Page 2Linked to original sources

PubMed2003

Search for phase specific genes in the brain of desert locust, Schistocerca gregaria (Orthoptera: Acrididae) by differential display polymerase chain reaction.

Differential display reverse transcriptase polymerase chain reaction (DDRT-PCR) in combination with semi-quantitative RT-PCR was used to compare differences in gene expression between the solitary and gregarious phase of Schistocerca gregaria. Twenty-six primer combinations were used, which produced 8 differential bands. Two out of the 8 differentials, one typical for the solitary and one for the gregarious phase, were further analyzed by semi-quantitative RT-PCR. The expression level of the solitary phase specific gene (SSG) was 2 times higher in solitary animals as compared to gregarious ones, while the gregarious specific gene (GSG) gave a 4-fold higher expression level in gregarious animals than in solitaries. Sequence analysis demonstrated that SSG does not belong to a known gene family, while the GSG belongs to the SPARC protein family.

Amino Acid Sequence↗

PubMed2003

Direct trocar insertion: alternative abdominal entry technique for laparoscopic surgery.

The study was designed to assess the feasibility of direct trocar technique for accessing the abdominal cavity for operative laparoscopy. A retrospective review of 1500 patients who underwent Laparoscopic cholecystectomy in Mymensingh Medical College Hospital and a private hospital between January 1999 and July 2002 was done. The transumbilical direct trocar entry method was used in 1375, the veress needle insertion technique was employed in 106 patients and open laparoscopy was used in 19 patients. Six (0.4%) Major complications occurred; 4 enterotomy and 2 omental herniation. All the enterotomy was related to primary access. Three (0.22%) during direct trocar entry method and another by open laparoscopy method. The bowel was repaired. Two patients had omental herniation through the umbilical port site related to open laparoscopy method which were repaired. Based on our experience the direct trocar technique is a safe approach to abdominal entry for laparoscopic surgery without prior pneumoperitoneum.

Abdomen↗

PubMed2003

A retrospective study on genito urinary Rhabdomyosarcoma.

A retrospective study was carried out on Genitourinary Rhabdomyosarcoma in the Department of Paediatric Surgery of Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh during the period January 1990 to December 1999. Total thirteen patients were treated during this period, age ranging from 1 month to 12 years. Eight patients were male and five were female (M: F = 1.6: 1). Diagnosis was made by history, thorough physical examination, digital rectal examination, ultrasonography, intravenous urography, CT scan and biopsy. All the patients were treated with chemoradiation theraphy as a first line of management and surgical excision was done for local residual tumours. Eight children (61.5%) were asymptomatic after completion of chemo-radiation therapy. Three (23.07%) patients discontinued the chemo-radiation schedule. Residual mass was present in one (7.7%) case for which partial cystectomy was done and the patient died in the 5th post operative day. Another patient (7.7%) who had pulmonary metastasis at the time of diagnosis, died during chemo-radiation therapy.

Child↗

PubMed2002

Class-associative multiple target detection by use of fringe-adjusted joint transform correlation.

We propose a class-associative correlation filter based technique for detecting a class of objects consisting of dissimilar patterns. The fringe-adjusted joint transform correlation algorithm is utilized to enhance the correlation performance, thus ensuring a strong and equal correlation peak for each element of the selected class. For enhanced performance, an enhanced version of the fringe-adjusted filter is incorporated in the class-associative multiple target detection process. The feasibility of the proposed technique has been tested by computer simulation.

Journal Article↗

PubMed2002

Search for peptidic molecular markers in hemolymph of crowd-(gregarious) and isolated-reared (solitary) desert locusts, Schistocerca gregaria.

An HPLC analysis of hemolymph extracts was undertaken to uncover differences between desert locusts, Schistocerca gregaria, reared under either crowded or isolated conditions. Some differences in the chromatographic pattern could be detected. One of the major peaks in the hemolymph of crowd-reared adults was found to be a minor one in isolated-reared individuals, whereas other peaks increased after solitarization. The differences became even more pronounced after several generations of isolated rearing. The dominant chromatographic peak in hemolymph extracts of the crowd-reared animals was identified as a novel peptide with a molecular mass of 6080Da. Edman degradation in combination with enzymatic fragmentation and quadrupole-time of flight (Q-Tof) mass spectrometry revealed the full sequence: DNADEDTICVAADNKFYLYANSLKLYTCYNQLPKVYVVKPKSQCRSSLSDCPTS. This 54 aa-peptide is very abundant in hemolymph of crowd-reared adults. Its concentration in hemolymph amounts to 0.1mM. To uncover the function, its effects were investigated in several bioassays, so far without positive results. One of the other peaks differentially expressed in the individuals of the two phases was identified as SGPI-2 (MW=3794Da), which is a serine protease inhibitor in locusts.

Amino Acid Sequence↗

PubMed2002

Congenital hearing impairment associated with rubella: lessons from Bangladesh.

Infection with rubella virus during pregnancy may cause fetal death or the multiple congenital fetal abnormalities that are known as congenital rubella syndrome (CRS). Studies have demonstrated that congenital hearing impairment is the most frequent abnormality associated with intrauterine rubella infection. In the present study, the first of its kind in Bangladesh, we investigated the presence of rubella antibody in hearing-impaired children in order to understand the possible role of rubella infection in the development of hearing impairment. A total of 198 hearing-impaired children and 200 children without hearing problems were studied. After taking a detailed history from the parents, blood samples were collected from both mothers and children; sera were subjected to enzyme-linked immunosorbent assay (ELISA) for anti-rubella IgG. Rubella antibody was detected in 74% of the hearing-impaired children and in 18% of those with normal hearing: this finding correlated with the presence of rubella antibody in the mothers (67%) of rubella seropositive hearing-impaired children. In contrast, we observed rubella antibody in only 14% of the mothers of the children without hearing problems. Consistent with the presence of antibody, 41% of the seropositive mothers who had hearing-impaired children gave a history of fever and rash during early pregnancy. Our study indicates a strong association between rubella infection and hearing impairment in Bangladeshi children. In addition, it also indicates that infection by rubella virus is common in Bangladesh: this suggests that priority should be given to implementing appropriate measures for the control of rubella.

Antibodies, Viral↗

PubMed2002

Quality of health care from patient perspectives.

The quality of health care is the consequence of strong link between service providers and user of the services. Perceived quality is one of the principal determinant of utilisation and non-utilisation of health services, a major issue in developing countries. Considering this, the present study was aimed to assess the quality of care in in-patient and outpatient departments of rural and urban government hospitals in Bangladesh. A total of 2420 patients were interviewed. The patients were selected by using systematic random sampling technique. Results revealed that age, waiting time, time spent for patient examination, place of treatment, income, years of schooling and male sex appeared to be independent predictors of patient satisfaction (p<0.001). Age, waiting time and years of schooling were negatively related with level of satisfaction indicating younger patients, less waiting time and patients with less education were more satisfied, whereas time spent for examination, income were positively related with patient's satisfaction. Patients attending at the urban hospitals and male sex were also significantly associated with patient's satisfaction. The study recommends that both short and long-term policy action should be adopted for quality assurance of the existing health care facilities in Bangladesh.

Adult↗

PubMed2001

Tuberculous spondylitis: analysis of 69 cases from Saudi Arabia.

DESIGN: Retrospective chart and radiographic review of all cases admitted to the authors' hospital and diagnosed to have tuberculous spondylitis. OBJECTIVE: To identify the frequency, presenting features, utility of diagnostic tests, and treatment outcome of spinal tuberculosis in a tertiary care center. METHODS: All cases of spinal tuberculosis treated in the authors' hospital over 14 years were reviewed. Only those with histologic or microbiologic confirmation or those who responded to antituberculous spondylitis therapy were included. Outcome was assessed according to predefined criteria. RESULTS: Between 1985 and 1998, 69 cases of tuberculous spondylitis were found, i.e., 5% of all tuberculous spondylitis cases diagnosed. The mean age was 52.8 years (range, 15-80 years), and 37 (53.6%) were male. Only five patients had a history of tuberculosis. The most frequent symptoms were backache (84%) and fever (32%), and the most frequent sign was spinal tenderness (45%). Nineteen (28%) patients had paraparesis and 12 (17%) had kyphosis. Except for elevated sedimentation rate (94.5%), the laboratory workup was not helpful. Both computed tomography and magnetic resonance imaging were found to be helpful in diagnosis, often with complementary information. Thirty-eight patients (55%) had thoracic spine involvement and 55 patients (80%) had paraspinal abscesses. Tissue aspirates had a yield of 70%, 35%, and 57% for granulomas, acid-fast bacilli smear, and culture, respectively. Medical therapy alone was given in 37 cases (54%), whereas 32 patients (46%) required additional surgical intervention, mainly those with spinal cord compression, spinal deformity, or risk of spinal instability. There was definite improvement in 63 cases (91%). The best outcome was in those patients presenting early before the occurrence of spinal deformity or neurologic symptoms. CONCLUSION: Tuberculous spondylitis is prevalent in the authors' hospital. Both computed tomography and magnetic resonance imaging are extremely helpful for diagnosis, and tissue aspirate is a good confirmatory method. A good outcome is expected if the diagnosis is made in early stages before the appearance of spinal deformity and neurologic symptoms. Surgical intervention can be avoided in these cases regardless of the presence or absence of paraspinal abscesses.

Adolescent↗

PubMed2001

Simultaneous zinc and vitamin A supplementation in Bangladeshi children: randomised double blind controlled trial.

OBJECTIVE: To evaluate the effect of simultaneous zinc and vitamin A supplementation on diarrhoea and acute lower respiratory infections in children. STUDY DESIGN: Randomised double blind placebo controlled trial. SETTING: Urban slums of Dhaka, Bangladesh. PARTICIPANTS AND METHODS: 800 children aged 12-35 months were randomly assigned to one of four intervention groups: 20 mg zinc once daily for 14 days; 200 000 IU vitamin A, single dose on day 14; both zinc and vitamin A; placebo. The children were followed up once a week for six months, and morbidity information was collected. RESULTS: The incidence and prevalence of diarrhoea were lower in the zinc and vitamin A groups than in the placebo group. Zinc and vitamin A interaction had a rate ratio (95% confidence interval) of 0.79 (0.66 to 0.94) for the prevalence of persistent diarrhoea and 0.80 (0.67 to 0.95) for dysentery. Incidence (1.62; 1.16 to 2.25) and prevalence (2.07; 1.76 to 2.44) of acute lower respiratory infection were significantly higher in the zinc group than in the placebo group. The interaction term had rate ratios of 0.75 (0.46 to 1.20) for incidence and 0.58 (0.46 to 0.73) for prevalence of acute lower respiratory infection. CONCLUSIONS: Combined zinc and vitamin A synergistically reduced the prevalence of persistent diarrhoea and dysentery. Zinc was associated with a significant increase in acute lower respiratory infection, but this adverse effect was reduced by the interaction between zinc and vitamin A.

Acute Disease↗

PubMed2001

Hemodynamic patterns of phosphatidylcholine hydroperoxide and hyaluronic acid during hepatic ischemia-reperfusion.

We investigated the hemodynamic pattern of serum hyaluronic acid (HA) and compared it with that of plasma phosphatidylcholine hydroperoxide (PCOOH) in terms of a convenient parameter of reperfusion injury. Using pig models, we designed two continuous ischemia groups, prepared by blockage of the blood flow at the hepatic hilum for 10 or 30 min. A discontinuous ischemia model was prepared by repeating the 10-min ischemia procedure, followed by 10 min of reperfusion, to a total ischemia period of 30 min. The PCOOH level started to increase just after reperfusion and reached the peak at 90 min, followed by a gradual decline after 6 h. The HA level increased rapidly in the continuous ischemia groups, starting immediately after ischemia onset until immediately before reperfusion, followed by a gradual decrease during up to 6 h of reperfusion. The HA levels in the three groups were almost normalized after 90 min of reperfusion, when the PCOOH level reached the peak. These results indicated that the plasma PCOOH level is a useful parameter for predicting the onset and progress of reperfusion injury in its initial stages.

Animals↗

PubMed2001

Epidemiological implications of the molecular characterization of foot-and-mouth disease virus isolated between 1996 and 2000 in Bangladesh.

Foot-and-mouth disease virus was collected during two years throughout Bangladesh. Viral RNA from 40 samples was subjected to reverse transcription-dependent polymerase chain reactions that amplify parts of the capsid protein encoding genome region, and the products obtained were sequenced. This showed that all virus isolates up to January 1999 belonged to a genotype of serotype O, observed here already in 1987, 1996 and 1997, and elsewhere since 1990. In February 2001, this virus variant was introduced into Great Britain and then transmitted to other European countries. The capsid protein sequences of an isolate of 2001 from the Netherlands is provided. Later isolates from Bangladesh, however, belonged to a genotype of serotype A that had been transmitted to Albania in 1996. No virus of type Asia1 was found, although it circulated in Bangladesh in 1996. Instead, this genotype of Asia1 virus was observed in Iran late in 1999, and transmitted from Turkey to Greece in July 2000. The results indicate continued intercontinental transmission of foot-and-mouth disease viruses that circulate in central Asia.

Amino Acid Sequence↗

PubMed2001

Enhanced inactivation and acceleration of activation of the sodium channel associated with epilepsy in man.

Generalized epilepsy with febrile seizures-plus (GEFS+) is a benign Mendelian syndrome characterized by childhood-onset febrile and afebrile seizures. Three point mutations within two voltage-gated sodium channel genes have been identified so far: in GEFS+ type 1 a mutation in the beta1-subunit gene SCN1B, and in GEFS+ type 2 two mutations within the neuronal alpha-subunit gene SCN1A. Functional expression of the SCN1B and one of the SCN1A mutations revealed defects in fast channel inactivation which are in line with previous findings on myotonia causing mutations in SCN4A, the skeletal muscle sodium channel alpha-subunit gene, all showing an impaired fast inactivation. We now studied the second GEFS+ mutation (T875M in SCN1A), using the highly homologous SCN4A gene (mutation T685M). Unexpectedly, the experiments revealed a pronounced enhancement of both fast and slow inactivation and a defect of channel activation for T685M compared to wild-type channels. Steady-state fast and slow inactivation curves were shifted in the hyperpolarizing direction, entry into slow inactivation was threefold accelerated, recovery from slow inactivation was slowed by threefold and the time course of activation was slightly but significantly accelerated. In contrast to other disease-causing mutations in SCN1A, SCN1B and SCN4A, the only mechanism that could explain hyperexcitability of the cell membrane would be the acceleration of activation. Because the enhancement of slow inactivation was the most obvious alteration in gating found for T685M, this might be the disease-causing mechanism for that mutation. In this case, the occurrence of epileptic seizures could be explained by a decrease of excitability of inhibitory neurons.

Animals↗

PubMed2001

Sperm disposal system in spermatic granuloma: a link with superoxide radicals.

Spermatic granulomas are believed to maintain "physiological harmony" in the male reproductive tract by maintaining a balance of hydrostatic pressure post-vasectomy. The mechanism for the disposal of deposited spermatozoa in the granuloma core is not clear. A fourfold rise in the production of superoxide along with ascorbyl and dienyl radicals and a 50% drop in the production of nitric oxide (NO) radicals by granuloma tissue hints that a reaction between NO and superoxide radicals could lead to the formation of peroxynitrite species which may contribute to the disposal of spermatozoa in the granuloma core. A higher protease activity and low hypoxanthine content in the granuloma indicates that a free radical driven sperm disposal system is active in granulomas.

Animals↗

PubMed2001

In vitro and in vivo expression of a nephritogenic Ig heavy chain determinant: pathogenic autoreactivity requires permissive light chains.

Lymphocyte antigen receptors are promising targets for immune intervention strategies in disorders marked by repertoire skewing or expansion of lymphocyte subsets. Appropriate application of immune receptor modulation is predicated on understanding the role of a particular receptor in pathogenesis and disease regulation. The VHB/W16 gene, restricted to mice carrying the j haplotype for the J558 family, is overexpressed by murine lupus anti-DNA Ig. This gene is also expressed recurrently among nephritogenic anti-DNA Ig recovered from several autoimmune strains, suggesting that cells expressing this pathogenic receptor are positively selected during disease progression. To explore the extent and mechanisms by which Ig H chains expressing this gene contribute to autoimmunity, an Ig H chain gene was engineered for in vitro and in vivo recombination studies. Site-directed mutagenesis generated unique restriction sites to link PCR-amplified V region (VDJ) cDNA to previously isolated genomic fragments containing Ig regulatory and signal sequences. The new 3 kb VDJ gene was then ligated to a 9 kb fragment encoding the IgM constant region. Transfection of H chain loss variant myeloma with the complete 12 kb construct, termed 238H-Cmicro, resulted in secretion of intact Ig pairing 238H-Cmicro, with a lambda L chain; however, transfectant Ig lacked autoreactivity and pathogenicity. Introduction of the 238H-Cmicro H chain as a transgene onto the non-autoimmune C57BL/6 background resulted in abundant B cell surface expression of 238H-Cmicro, however, four transgenic Ig recovered by fusion of LPS-stimulated splenocytes and formed by combination of 238H-Cmicro, with endogenous kappa chains do not bind DNA or laminin. These results indicate that the antigen binding sites encoded by this disease-associated gene and/or H chain must associate with permissive L chains to specify autoimmunity. The 238H-Cmicro, transgenic model should prove useful in dissecting the in vivo fate of 238H-Cmicro, L combinations that produce pathogenic autoreactive receptors and in evaluating receptor-targeted interventions.

Amino Acid Sequence↗

PubMed2001

Chronic arsenic toxicity in Bangladesh and West Bengal, India--a review and commentary.

Fifty districts of Bangladesh and 9 districts in West Bengal, India have arsenic levels in groundwater above the World Health Organization's maximum permissible limit of 50 microg/L. The area and population of 50 districts of Bangladesh and 9 districts in West Bengal are 118,849 km2 and 104.9 million and 38,865 km2 and 42.7 million, respectively. Our current data show arsenic levels above 50 microg/ L in 2000 villages, 178 police stations of 50 affected districts in Bangladesh and 2600 villages, 74 police stations/blocks of 9 affected districts in West Bengal. We have so far analyzed 34,000 and 101,934 hand tube-well water samples from Bangladesh and West Bengal respectively by FI-HG-AAS of which 56% and 52%, respectively, contained arsenic above 10 microg/L and 37% and 25% arsenic above 50 microg/L. In our preliminary study 18,000 persons in Bangladesh and 86,000 persons in West Bengal were clinically examined in arsenic-affected districts. Of them, 3695 (20.6% including 6.11% children) in Bangladesh and 8500 (9.8% including 1.7% children) in West Bengal had arsenical dermatological features. Symptoms of chronic arsenic toxicity developed insidiously after 6 months to 2 years or more of exposure. The time of onset depends on the concentration of arsenic in the drinking water, volume of intake, and the health and nutritional status of individuals. Major dermatological signs are diffuse or spotted melanosis, leucomelanosis, and keratosis. Chronic arsenicosis is a multisystem disorder. Apart from generalized weakness, appetite and weight loss, and anemia, our patients had symptoms relating to involvement of the lungs, gastrointestinal system, liver, spleen, genitourinary system, hemopoietic system, eyes, nervous system, and cardiovascular system. We found evidence of arsenic neuropathy in 37.3% (154 of 413 cases) in one group and 86.8% (33 of 38 cases) in another. Most of these cases had mild and predominantly sensory neuropathy. Central nervous system involvement was evident with and without neuropathy. Electrodiagnostic studies proved helpful for the diagnosis of neurological involvement. Advanced neglected cases with many years of exposure presented with cancer of skin and of the lung, liver, kidney, and bladder. The diagnosis of subclinical arsenicosis was made in 83%, 93%, and 95% of hair, nail and urine samples, respectively, in Bangladesh; and 57%, 83%, and 89% of hair, nail, and urine samples, respectively in West Bengal. Approximately 90% of children below 11 years of age living in the affected areas show hair and nail arsenic above the normal level. Children appear to have a higher body burden than adults despite fewer dermatological manifestations. Limited trials of 4 arsenic chelators in the treatment of chronic arsenic toxicity in West Bengal over the last 2 decades do not provide any clinical, biochemical, or histopathological benefit except for the accompanying preliminary report of clinical benefit with dimercaptopropanesulfonate therapy. Extensive efforts are needed in both countries to combat the arsenic crisis including control of tube-wells, watershed management with effective use of the prodigious supplies of surface water, traditional water management, public awareness programs, and education concerning the apparent benefits of optimal nutrition.

Adult↗

PubMed2001

The structure of the lipooligosaccharide (LOS) from the alpha-1,2-N-acetyl glucosamine transferase (rfaK(NMB)) mutant strain CMK1 of Neisseria meningitidis: implications for LOS inner core assembly and LOS-based vaccines.

The inner core structures of the lipooligosaccharides (LOS) of Neisseria meningitidis are potential vaccine candidates because both bactericidal and opsonic antibodies can be generated against these epitopes. In an effort to better understand LOS biosynthesis and the potential immunogenicity of the LOS inner core, we have determined the LOS structure from a meningococcal rfaK mutant CMK1. The rfaK gene encodes the transferase that adds an alpha-N-acetylglucosaminosyl residue to O-2 of the inner core heptose (Hep) II of the LOS. The LOS oligosaccharide from this mutant was previously shown to contain only Hep, 3-deoxy-D-manno-2-octulosonic acid (Kdo), and multiple phosphoethanolamine (PEA) substituents (Kahler et al., 1996a, J. Bacteriol., 178, 1265-1273). The complete structure of the oligosaccharide (OS) component of the LOS from mutant CMK1 was determined using glycosyl composition and linkage analyses, and 1H, 13C, and 31P nuclear magnetic resonance spectroscopy. The CMK1 OS structure contains a PEA group at O-3 of Hep II in place of the usual glucosyl residue found at this position in the completed L2 LOS glycoform from the parent NMB strain. The PEA group at O-6 of Hep II, however, is present in both the CMK1 mutant LOS and parental NMB L2 LOS structures. The structure of the OS from CMK1 suggests that PEA substituents are transferred to both the O-3 and O-6 positions of Hep II prior to: (1) the incorporation of the alpha-GlcNAc on Hep II; (2) the synthesis of the alpha-chain on Hep I; and (3) the substitution of the glycosyl residue at the O-3 Hep II, which distinguishes L2 and L3 immunotypes. The LOS structure of the CMK1 mutant makes it a candidate immunogen that could generate broadly cross-reactive inner-core LOS antibodies.

Bacterial Proteins↗

PubMed2001

Paradoxical increase in nitric oxide synthase activity in hypercholesterolaemic rats with impaired renal function and decreased activity of nitric oxide.

BACKGROUND: We have shown that acute exposure of oxidized low-density lipoprotein (OX-LDL) induces vasoconstriction in renal vessels and reduces glomerular filtration rate (GFR) in an isolated perfused rat kidney model by decreasing the activity of nitric oxide (NO). L-arginine has a protective role against OX-LDl-induced vasoconstriction. Micropuncture studies have demonstrated that short-term diet-induced hypercholesterolaemia is associated with decreased GFR and renal blood flow and increased glomerular capillary pressure. This may be mediated by decreased activity of NO. METHODS: Rats were made hypercholesterolaemic by supplementing the standard chow with 4% cholesterol and 1% sodium cholate. A group of rats on hypercholesterolaemic diet also received L-arginine in the drinking water. After 4 and 6 weeks, blood samples and 24-h urine samples were collected for the measurement of biochemical parameters. After 6 weeks, all rats were subjected to isolated perfusion of kidneys at a constant pressure of 100 mmHg. During isolated perfusion, the unused contralateral kidney was taken for morphological studies and for assessing the activity of nitric oxide synthase enzyme by beta-NADPH diaphorase histochemistry. RESULTS: Rats fed a high-cholesterol diet had LDL levels 3-6 times greater than the rats fed standard chow. Rats that received L-arginine in the drinking water had serum L-arginine levels 5-6 times greater than control rats. At 6 weeks, creatinine clearance was significantly lower in the rats on the high-cholesterol diet compared to the rats on standard chow and rats on high-cholesterol diet plus L-arginine. Twenty-four-hour urinary total nitrate and nitrite excretion in the hypercholesterolaemic rats was 1.5-2 times greater than that of control rats. Twenty-four-hour urinary cGMP excretion was significantly lower in the rats on a high-cholesterol diet, but in the rats on high-cholesterol diet and L-arginine, 24-h urinary cGMP excretion was not significantly different from that of control rats. During isolated perfusion of kidneys, renal perfusate flow was found to be significantly reduced in the kidneys taken from the rats on a high-fat diet compared to controls. L-arginine supplementation in the drinking water almost completely reversed the effect of a high-fat diet. Inulin clearance was also significantly reduced in kidneys on a high-fat diet in contrast to controls but not in kidneys on high fat-diet and L-arginine. Basal cGMP excretion in urine was significantly lower in the kidneys taken from the rats on a high-fat diet compared to controls. L-arginine supplementation restored the basal cGMP excretion in these kidneys. NO synthase (NOS) enzyme activity as assessed by NADPH diaphorase activity showed that kidney sections taken from the rats on a high-fat diet showed more intense staining, indicating increased activity compared to the kidney sections taken from the rats on a normal diet. CONCLUSION: Though activity of NO is diminished in hypercholesterolaemic rats with impaired renal function, there is a paradoxical increase in NO production and NOS activity. L-arginine reverses the effects of a high-fat diet.

Animals↗

PubMed2001

Diminished diarrheal response to Vibrio cholerae strains carrying the replicative form of the CTX(Phi) genome instead of CTX(Phi) lysogens in adult rabbits.

Toxigenic Vibrio cholerae strains are lysogens of CTX(Phi), a filamentous bacteriophage which encodes cholera toxin (CT). Following infection of recipient V. cholerae cells by CTX(Phi), the phage genome either integrates into the host chromosome at a specific attachment site (attRS) or exists as a replicative-form (RF) plasmid. We infected naturally occurring attRS-negative nontoxigenic V. cholerae or attenuated (CTX(-) attRS negative) derivatives of wild-type toxigenic strains with CTX(Phi) and examined the diarrheagenic potential of the strains carrying the RF of the CTX(Phi) genome using the adult rabbit diarrhea model. Under laboratory conditions, strains carrying the RF of CTX(Phi) produced more CT than corresponding lysogens as assayed by a G(M1)-based enzyme-linked immunosorbent assay and by fluid accumulation in ligated ileal loops of rabbits. However, when tested for diarrhea in rabbits, the attRS-negative strains (which carried the CTX(Phi) genome as the RF) were either negative or produced mild diarrhea, whereas the attRS-positive strains with integrated CTX(Phi) produced severe fatal diarrhea. Analysis of the strains after intestinal passage showed that the attRS-negative strains lost the phage genome at approximately a fivefold higher frequency than under in vitro conditions, and 75 to 90% of cells recovered from challenged rabbits after 24 h were CT negative. These results suggested that strains carrying the RF of CTX(Phi) are unable to cause severe disease due to rapid loss of the phage in vivo, and the gastrointestinal environment thus provides selection of toxigenic strains with an integrated CTX(Phi) genome. These results may have implications for the development of live V. cholerae vaccine candidates impaired in chromosomal integration of CTX(Phi). These findings may also contribute to understanding of the etiology of diarrhea occasionally associated with nontoxigenic V. cholerae strains.

Animals↗