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Biomedical subjects

N Rahman

Publications and source records attributed to N Rahman.

At least 73 records · Page 4Linked to original sources

The familial Wilms' tumour susceptibility gene, FWT1, may not be a tumour suppressor gene.

A familial Wilms' tumour susceptibility gene, known as FWT1, has recently been localised to chromosome 17q12-q21 by genetic linkage analysis. Four Wilms' tumours from a family showing strong evidence of linkage to FWT1 were examined for allele loss using polymorphic microsatellite markers on chromosome 17q. In three tumours no loss of heterozygosity was observed. In the remaining case, loss of heterozygosity was detected at all markers analysed. However, the alleles lost in this Wilms' tumour were those segregating with the disease in the family. This is in contrast to the usual pattern observed in familial cancer syndromes, where the allele lost in tumours arising in gene carriers is the wild type inherited from the non mutation carrying parent. Taken together with previous data indicating that LOH on chromosome 17q is rare in sporadic Wilms' tumour, the results suggest that FWT1 is not a tumour suppressor gene. Moreover, loss of alleles linked to the disease and the implied absence of the mutated susceptibility gene in one tumour, suggests that a mutation in FWT1 may be necessary for the initiation of some familial Wilms' tumours but subsequently the maintenance of the neoplastic phenotype becomes independent of the FWT1 mutation.

Alleles↗

Use of integral and differential methods for the determination of L-dopa in pure form and pharmaceutical preparations.

A new simple and selective kinetic method for the determination of L-dopa, using differential and integral methods, is described. The spectrophotometric measurements were recorded by measuring the increase in absorbance at 300 nm. The concentration range was valid from 5-35 ppm. The complex ratio showed a (1:2) of L-dopa with respect to sodium hydroxide, with formation constant 5.06 x 10(6) and molar absorptivity of 3.85 x 10(3) l mol-1 cm-1.

Antiparkinson Agents↗

Multiloculated hydrocephalus related to cerebrospinal fluid shunt infection.

This study is an attempt to establish that CSF shunt infection has a role in the aetiology of multiloculated hydrocephalus. The authors carried out a review of 12 cases of multiloculated hydrocephalus who were treated at King Khalid University Hospital between 1988-1994. The multiloculation appears to have developed following the shunt infection in all cases. The hydrocephalus was related to an intraventricular haemorrhage (IVH) in 9 patients and was congenital in 2 patients and post-meningitic in 1 patient. The shunt infection was caused by a gram-negative organism in 8 patients and duration of external ventricular drainage ranged from 9-24 (median 13) days. The diagnosis of multiloculated hydrocephalus was made on average 2 months after the shunt infection. In three patients endoscopic fenestration of intraventricular septations was attempted but was effective in only one case. The other patients were managed by two shunts (9 patients) and three shunts (2 patients). At a mean follow-up of 15 months, the shunt revision rate of the patients was 0.4/year. One patient died of multiple brain abscesses and 6 patients remain severely disabled. The poor outcome may also be related to the original IVH as well as the multiloculated hydrocephalus. The study also shows that patients with post-haemorrhagic hydrocephalus, who develop a shunt infection due to gram-negative organisms and in whom the CSF fails to be cleared of the infection following 12 days of external drainage appear to be at risk of developing multiloculated hydrocephalus.

Adolescent↗

Evidence for a familial Wilms' tumour gene (FWT1) on chromosome 17q12-q21.

Wilms' tumour (WT) is one of the most common solid tumours of childhood, occurring in 1 in 10,000 children and accounting for 8% of childhood cancers. It is believed to result from malignant transformation of abnormally persistent renal stem cells (nephrogenic rests) which retain embryonic differentiation potential. Although WT is usually sporadic, approximately one percent occur in families in which susceptibility appears to be inherited as an autosomal dominant trait with incomplete penetrance. Predisposition to other cancers or to the developmental abnormalities associated with sporadic WT is not usually apparent in WT families. The WT1 gene at 11p13 (ref.2), and additional genes on chromosomes 11p15 (ref. 3) and 16q (ref. 4) have been implicated in the development of WT but are not responsible for familial WT. We have carried out a genome linkage search in a large Canadian family with seven confirmed cases of WT. Our results provide strong evidence for the localisation of a familial WT predisposition gene, FWT1, to an 18-centimorgan (cM) interval on chromosome 17q12-q21.

Child↗

Hand washing with soap reduces diarrhoea and spread of bacterial pathogens in a Bangladesh village.

Hand washing with soap and water can prevent the spread of diarrhoeal diseases in areas where comparatively costly interventions, such as supply of safe water and improved sanitation, are not possible. In this study, the practice of hand washing with soap and water was instituted in a periurban slum of Dhaka city, and the surveillance for diarrhoea sustained for a one-year period. Rates of primary and secondary attacks were compared to those of a non-intervention area similar in age structure, economic status, education, and other relevant variables. Rectal swabs of cases and contacts established aetiologies. There was a large (2.6 fold) reduction in diarrhoeal episodes in the intervention area during the observation period. Rates of bacterial pathogens were also lower in the intervention area. Significant reduction in diarrhoeal incidences was observed in all age groups for all pathogens except for rotavirus. These observations if implemented as health policy could reduce the spread of diarrhoeal diseases at low cost in high risk areas.

Adolescent↗

Intracranial mycotic infections in neurosurgical practice.

Intracranial mycotic infections requiring neurosurgical intervention are being diagnosed more frequently. This study is a review of 17 cases of intracranial mycotic infections that were treated in a neurosurgical unit in Saudi Arabia over an 8-year period. A primary focus of infection was identified in 41% of patients while 18% of patients had a predisposing factor. Forty-seven percent of patients presented with a brain abscess (solitary 29%, multiple 18%) while 35% had a granuloma. 18% meningitis and ventriculitis and 12% hydrocephalus. The Aspergillus species and Ramichloridium machenziei were the commonest pathogens. Following the appropriate surgical and antimicrobial treatment, the mortality rate was 41% and there was evidence of residual disease at follow-up in 18%. The reason for a fatal outcome was failure to consider a fungal aetiology and to obtain a tissue diagnosis early-because of late referral (2 cases), as well as failure to respond to antimycotic therapy (4 cases) and rupture of the internal carotid artery due to Aspergillus arteritis (one case). It is concluded that an early tissue diagnosis is crucial in the management of intracranial mycotic infection so that the appropriate surgical and antimycotic treatment can be started early.

Adult↗

Neurosurgical management of intraventricular haemorrhage in preterm infants.

A review of intraventricular haemorrhage (IVH) diagnosed in 103 preterm infants from 1983 to 1993 describes the presenting features and management of this condition. In this 10-year period, 37 infants with IVH developed post-haemorrhagic hydrocephalus (PHH), defined as ventriculomegaly, raised intracranial pressure and increasing head circumference. PHH was treated by external ventricular drainage and/or ventriculo-peritoneal shunting; but other drainage procedures like lumbar punctures and subcutaneous ventricular reservoir were used occasionally. Relative indications, merits and demerits of these various surgical options is discussed and results summarized. High incidence of neuro-developmental handicap and its correlation with the grade of haemorrhage and PHH is emphasized. External ventricular drainage (EVD) was found to be an effective and safe therapy for rapidly progressive PHH and increased intracranial pressure. Ultimate outcome depended mainly on the grade of haemorrhage, severity of PHH and promptness of its neurosurgical management.

Cerebral Hemorrhage↗

Choroidal detachment associated with retinal detachment as a presenting finding.

Choroidal detachment along with retinal detachment as a presenting finding is rare. We identified five such cases presenting to our ophthalmology practice between 1964 and 1991. The patient is usually myopic and presents with marked visual loss, profound hypotony and a marked anterior chamber reaction. The pathogenesis seems to revolve around the hypotony and myopia and an unstable choroidal vascular system. Management usually involves a scleral buckling procedure with cryotherapy under direct visualization to release choroidal and subretinal fluid, possibly preceded by a few days of anti-inflammatory therapy. The overall prognosis is poor owing to delays in diagnosis and the postoperative development of proliferative vitreoretinopathy.

Adult↗

Prognostic indicators and risk factors for increased duration of acute diarrhoea and for persistent diarrhoea in children.

To identify the prognostic indicators and risk factors for increased duration of acute diarrhoea and for occurrence of persistent diarrhoea (i.e. acute episodes lasting longer than 14 days) in children under three years, a systematic sample (3690) of patients attending a large treatment centre in Bangladesh was analysed using multiple regression, logistic regression and stratified (Mantel-Haenszel) analysis. Significant prognostic indicators or risk factors for increase in duration of acute diarrhoea, after adjusting for confounders, include bloody or mucoid diarrhoea, concomitant signs of chest infection, presence of vitamin A deficiency signs, decreased weight for age, routine use of contaminated surface water, lack of breastfeeding and increasing age; presence of rotavirus or enterotoxigenic Escherichia coli or Vibrio cholerae 01 in stool had negative association. In logistic regression and stratified analysis these factors, except for lack of breastfeeding and age, were also found to be risk factors or prognostic indicators of persistent diarrhoea. Policy implications of these findings for programmes to reduce morbidity and mortality from persistent diarrhoea include development of effective vaccines against dysentery-causing Shigella, programmes to prevent vitamin A deficiency, protein energy malnutrition and acute respiratory infections in children, and long-term programmes to provide clean water for all day-to-day needs.

Acute Disease↗

Cryptosporidiosis: a cause of diarrhea in Bangladesh.

Fecal samples from diarrheal patients and non-diarrheal controls were examined for Cryptosporidium oocysts in a year-long prospective study at a diarrhea treatment center in Dhaka, Bangladesh. Cryptosporidium oocysts were detected in 42 (3%) of 1,382 diarrheal patients but in none of 235 non-diarrheal controls. In 32 (76%) of 42 patients, no other enteropathogens were detected. Children less than 5 years of age were more commonly infected than older children (4.8% vs. 1.6%, P greater than 0.05) and adults (4.8% vs. 0.2%, P less than 0.01). A higher number of cases were detected during hot and humid months (April--July). Nineteen children less than 5 years of age (index cases) and their 71 family members were followed for 3 weeks after the release of the index cases from the hospital. Diarrhea continued for greater than 14 days (persistent diarrhea) in 8 (32%) index children. Cryptosporidium oocysts were detected in 1 (12.5%) of 8 family members who developed diarrhea during the follow-up period. Index cases excreted oocysts for 3-28 days (12.37 +/- 8.35 days). Almost all the patients recovered with oral rehydration. Cryptosporidium ssp. cause self-limited diarrhea episodes in children less than 5 years of age in Bangladesh, with a low frequency of intrafamilial transmission.

Adolescent↗

Impact of acute diarrhoea on parasite loads.

Parasites and diarrhoea are more frequent in poor populations. Parasite prevalence rates in post-diarrhoeal patients of the International Centre for Diarrhoeal Disease Research (ICDDRB) and in non-diarrhoeal populations of two Dhaka poor socioeconomic communities have been compared to explore if there is any effect of acute diarrhoea on parasite prevalence rates. Stool of a 4% systemic randomly selected sample of diarrhoeal patients and the whole population of two local poor communities have been examined. The results showed that the prevalence of parasites in a post-diarrhoeal population is significantly lower than in a non-diarrhoeal population. These reductions (E. hist. 10.2% vs. 2.03%, G. lamb. 9.7% vs. 3.5%, hookworm 37.4% vs. 4.7% and Ascaris lumbricoides 81% vs. 20.6%) may be attributed mainly to the flushing effect of diarrhoea.

Acute Disease↗

Risk factors for persistent diarrhoea.

With a systematically sampled population of children aged under 5 attending this centre for diarrhoeal disease research during 1983-5 a retrospective analysis of persistent diarrhoea (defined as greater than 14 days' duration) was performed to identify the possible risk factors for this syndrome. Of the 4155 children included in the analysis, 410 (10%) gave a history of persistent diarrhoea. A comparison with children with acute diarrhoea matched for age showed that 11 factors were correlated with persistent diarrhoea, and strongly associated factors were stools with blood or mucus, or both, lower respiratory tract infection, malnutrition, vitamin A deficiency, and antibiotic use before presentation. The peak age was 2 years, and there was no sex difference. Deaths occurred more often in the group with persistent diarrhoea. Although Shigella spp, Campylobacter jejuni, and Giardia lamblia were frequently identified, their rates of isolation were not significantly higher among patients with persistent diarrhoea. No seasonal variation was observed in the rates of persistent diarrhoea. Although the introduction of family food to the diet was associated with higher rates, this factor was difficult to separate from the age dependent risks.

Acute Disease↗

Cholera, rotavirus and ETEC diarrhoea: some clinico-epidemiological features.

This paper analyses a few selected features from the history and clinical examination of 1258 patients with acute diarrhoea and a single laboratory diagnosis of either cholera, rotavirus, or enterotoxigenic (ETEC) Escherichia coli infection. Age distribution and seasonality in Bangladesh were also studied. The duration of illness before admission was not significantly different in the 3 groups. Cholera occurred especially in the spring and early winter. Most cholera patients were between 3 and 10 years of age. Over 37% of the patients developed severe dehydration. In about 90% of cholera cases, the stools were alkaline (pH greater than 7). ETEC infections were seen mostly in April-May and September-October. Infants were frequently affected but from age 25 onwards the age distribution closely followed that of cholera. Severe dehydration occurred in 8.3% of patients and was more frequent than in rotavirus cases. Stool pH was as frequently acidic as basic. Rotavirus cases were concentrated during the winter in patients under 2 years of age. They had marked vomiting, yet severe dehydration was almost absent. Cough was present in half of them. The stools were usually acidic. In spite of considerable overlap of signs and symptoms between the 3 aetiological groups, a presumptive diagnosis of cholera could be made in patients past infancy and early childhood who showed very severe dehydration. However, age-specific prevalence was strikingly different and seasonal variations considerable.

Adolescent↗