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Biomedical subjects

A Ghosh

Publications and source records attributed to A Ghosh.

At least 181 records · Page 10Linked to original sources
PubMed1997

Second-trimester hydrops fetalis in pregnancies affected by homozygous alpha-thalassaemia-1.

Homozygous alpha-thalassaemia-1 is the commonest cause of hydrops fetalis in South-East Asia. Ultrasonographic features of hydrops fetalis were said to be evident only after 20 weeks of gestation. We studied 111 pregnancies at risk of homozygous alpha-thalassaemia-1 at 12-14 gestational weeks and 101 pregnancies at 17-18 weeks by abdominal ultrasound examination. Ultrasonographic features of hydrops fetalis were seen in 3 out of 44 pregnancies affected by homozygous alpha-thalassaemia-1 at 12-14 weeks [7 per cent; 95 per cent confidence interval (CI) 1-19 per cent] and in 7 out of 21 affected pregnancies at 17-18 weeks (33 per cent; 95 per cent CI 15-57 per cent). In conclusion, homozygous alpha-thalassaemia-1 can cause hydrops fetalis in the early second trimester. It should constitute one of the differential diagnoses in the work-up of second-trimester hydrops fetalis.

Diagnosis, Differential↗
PubMed1997

Unusual presentation of bilateral abdominoscrotal hydrocele in a child.

An 18-month-old boy who had bilateral abdominoscrotal hydroceles presented with an acute inflammation of the left hydrocele followed 1 week later by similar spontaneous inflammation of the right side. He was treated with excision of both hydrocele sacs. A review of the literature shows that this is the first report of an abdominoscrotal hydrocele presenting in this unusual fashion.

Abdomen↗
PubMed1997

Regulation of dendritic growth and remodeling by Rho, Rac, and Cdc42.

The acquisition of cell type-specific morphologies is a central feature of neuronal differentiation and has important consequences for nervous system function. To begin to identify the underlying molecular mechanisms, we have explored the role of Rho-related GTPases in the dendritic development of cortical neurons. Expression of dominant negative mutants of Rac or Cdc42, the Rho-inhibitory molecule C3 transferase, or the GTPase-activating protein RhoGAP p190 causes a marked reduction in the number of primary dendrites in nonpyramidal (multipolar) neurons and in the number of basal dendrites in neurons with pyramidal morphologies. Conversely, the expression of constitutively active mutants of Rho, Rac, or Cdc42 leads to an increase in the number of primary and basal dendrites. In cortical cultures, as in vivo, dendritic remodeling leads to an apparent transformation from pyramidal to nonpyramidal morphologies over time. Strikingly, this shift in favor of nonpyramidal morphologies is also inhibited by the expression of dominant negative mutants of Cdc42 and Rac and by RhoGAP p190. These observations indicate that Rho, Rac, and Cdc42 play a central role in dendritic development and suggest that differential activation of Rho-related GTPases may contribute to the generation of morphological diversity in the developing cortex.

Animals↗
PubMed1997

Molecular characterization of Vibrio cholerae O1 biotype El Tor strains isolated between 1992 and 1995 in Calcutta, India: evidence for the emergence of a new clone of the El Tor biotype.

Sixty-one clinical strains of Vibrio cholerae O1 El Tor isolated in Calcutta before, during, and after the V. cholerae O139 Bengal outbreak were examined to see if the O1 strains of the post-O139 period were different from those in existence before. Comparison of the restriction fragment length polymorphism of the rRNA genes (ribotyping) and the CTX genetic element revealed that all "before" strains except 1 belonged to a single known ribotype, whereas all "after" strains except 2 belonged to a hitherto undescribed ribotype. Also, 23 of 25 "before" strains harbored two or more copies of CTX in tandem and also a "free" RS1 element away from CTX, whereas 19 of 21 "after" strains had a single copy of CTX and no free RS1 element. CTX occupied different chromosomal locations in "before" and "after" strains. These studies clearly showed that El Tor O1 strains, which displaced V. cholerae O139 in Calcutta, belonged to a new clone and suggested that there is a continuous genetic reassortment among El Tor strains of V. cholerae O1.

Blotting, Southern↗
PubMed1997

Unique organization of the CTX genetic element in Vibrio cholerae O139 strains which reemerged in Calcutta, India, in September 1996.

We studied the restriction fragment length polymorphism of the rRNA gene and CTX genetic element in Vibrio cholerae O139 Bengal, which resurged in Calcutta in September 1996 after a gap of 32 months. While the strains from this resurgence were indistinguishable from the earlier strains by ribotyping, the structure of the CTX genetic element present in the current O139 strains was found to be unconventional.

Cholera↗
PubMed1997

Forking genetic algorithms: GAs with search space division schemes.

In this article, we propose a new type of genetic algorithm (GA), the forking GA (fGA), which divides the whole search space into subspaces, depending on the convergence status of the population and the solutions obtained so far. The fGA is intended to deal with multimodal problems that are difficult to solve using conventional GAs. We use a multipopulation scheme that includes one parent population that explores one subspace and one or more child populations exploiting the other subspace. We consider two types of fGAs, depending on the method used to divide the search space. One is the genotypic fGA (g-fGA), which defines the search subspace for each subpopulation, depending on the salient schema within the genotypic search space. The other is the phenotypic fGA (p-fGA), which defines a search subspace by a neighborhood hypercube around the current best individual in the phenotypic feature space. Empirical results on complex function optimization problems show that both the g-fGA and p-fGA perform well compared to conventional GAs. Two additional utilities of the p-fGA are also studied briefly.

Algorithms↗
PubMed1997

Short report: Leishmania DNA in Phlebotomus and Sergentomyia species during a kala-azar epidemic.

The presence of Leishmania donovani DNA in sand flies caught in Indian kala-azar patients' dwellings during the epidemic of 1990-1992 was studied using the polymerase chain reaction (PCR). Amplification of miniexon-derived RNA genes and gpG3 mRNA was achieved in single Phlebotomus argentipes, P. papatasi, and Sergentomyia babu flies. The data suggest the possible involvement of multiple sandfly species in kala-azar transmission.

Animals↗
PubMed1997

Early ultrasound prediction of pregnancies affected by homozygous alpha-thalassaemia-1.

Homozygous alpha-thalassaemia-1 is conventionally diagnosed by invasive testing on all at-risk pregnancies. We evaluated the diagnostic efficacy of non-invasive abdominal ultrasonographic cardiothoracic ratio measurement in 62 pregnancies at 13-14 weeks and 75 pregnancies at 17-18 weeks. This performed better than placental thickness measurement. Using a cardiothoracic ratio cut-off level of > or = 0.5, 75 per cent of affected pregnancies were detected at 13-14 weeks and all cases were detected at 17-18 weeks. False-positive rates were 7 and 8 per cent, respectively. There was no false-positive diagnosis if the cardiothoracic ratio was > or = 0.53. With this approach, invasive procedures can be selectively performed and fewer pregnancies will be lost unnecessarily. The reduction in medical expenses is likely to be substantial.

False Positive Reactions↗
PubMed1997

Infectious mononucleosis hepatitis: report of two patients.

Icteric hepatitis and fulminant hepatic failure (FHF) are rare in infectious mononucleosis (IM). We report two patients with icteric IM hepatitis; one died after developing FHF, the other recovered uneventfully. Epstein-Barr virus infection causing hepatitis and FHF should be suspected when tests for other hepatotrophic viral infections are negative.

Adolescent↗
PubMed1997

The risk of alpha-thalassaemia in offspring of beta-thalassaemia carriers in Hong Kong.

Couples in whom one is heterozygous for alpha-thalassaemia-1 and the other is heterozygous for beta-thalassaemia are assumed not to be at risk of having offspring with homozygous alpha-thalassaemia-1 or homozygous beta-thalassaemia. We retrospectively reviewed the genetic outcome of 189 pregnancies of 178 couples in whom the partners were diagnosed to be discordant heterozygotes of alpha-thalassaemia and beta-thalassaemia on haematological tests. Zeta gene mapping was performed on 158 beta-thalassaemia carriers to diagnose the presence of co-existing alpha-thalassaemia-1. Eleven patients (7 per cent) were found to be compound alpha- and beta-thalassaemia heterozygotes. They accounted for 16 pregnancies, of which five were diagnosed to be affected by homozygous alpha-thalassaemia-1. Our results show that couples presumed to be discordant heterozygotes of alpha- and beta-thalassaemia on haematological testing are at risk of having offspring with homozygous alpha-thalassaemia-1 if the zeta gene mapping of the heterozygous beta-thalassaemia partner shows co-inheritance of alpha-thalassaemia-1. Prenatal diagnosis of homozygous alpha-thalassaemia-1 should be performed on these at-risk pregnancies.

Chromosome Mapping↗
PubMed1997

Pattern of solid malignant tumours in children--a ten-year study.

Solid malignant tumours (n = 263) excluding brain and spinal cord tumours in children up to 14 years of age were studied. Retinoblastoma (27%) constituted the largest group followed by Wilms' tumour (14.1%) and lymphoma (13.7%). Most patients (55%) were of less than 5 years age and maximum incidence of embryonal tumours was found in this age group; other tumours were more frequent in higher age. A male preponderance was noted (male to female ratio as 1.6:1). Amongst lymphoma, 61% were non-Hodgkin's lymphoma and rest were Hodgkin's disease; 2 cases of Burkitt's lymphoma were found. Other notable tumours encountered in the study were embryonal rhabdomyosarcoma (n = 14), hepatoblastoma (n = 9), neuroblastoma (n = 7), Ewing's sarcoma (n = 21), osteogenic sarcoma (n = 19) and germ cell tumours (n = 14).

Adolescent↗
PubMed1997

Study of pregnancy outcome over a period of five years in a postgraduate institute of west Bengal.

This study is a retrospective analysis of the pregnancy outcome over a period of 5 years at IPGME&R and SSKM Hospital, Calcutta. Of the total 13,211 obstetrical admissions during the period from 1st January, 1990 to 31st December, 1994, 32.6% cases were admitted for antenatal complications, 27.3% for antenatal observations, 0.5% for postpartum complications and 39.4% for medical termination of pregnancy. Vaginal delivery was carried out in 50% of cases of which 78.7% were of normal vaginal delivery and 21.2% were of instrumental delivery. In the remaining cases caesarean section was done of which again 58.1% was elective and 41.8% was emergency caesarean sections. Maternal mortality was 4.6/1,000 live births. Perinatal mortality rate was 3.9%. The analysed data reflect the fact that the maternal mortality and perinatal mortality were well controlled over this period in spite of a large number of complicated cases being referred to this hospital with minimum facilities.

Female↗
PubMed1997

Limb reduction defects in fetuses with homozygous alpha-thalassaemia-1.

Limb reduction defect is a rare event. Its exact pathogenesis is unknown. We retrospectively reviewed the outcome of 130 fetuses affected by homozygous alpha-thalassaemia-1 and found that 11 of them (8 per cent; 95 per cent confidence interval: 4-13 per cent) had terminal transverse limb reduction defects. Chromosome study was available in ten fetuses with limb defects and the results were normal. We postulate that the strong association between homozygous alpha-thalassaemia-1 and limb reduction is related to the hypoxic insult in early gestation. This may be the final common pathway in the pathogenesis of other forms of limb reduction defects.

Female↗
PubMed1997

Influence of haloperidol on testicular functions in rat.

The study involved exploration of the role of dopamine antagonist haloperidol on the testicular functions of rat. Chronic administration of haloperidol (0.2 mg/kg/day/sc for 21 days) caused significant increase in brain DA and serum prolactin. At testicular level the treatment revealed atrophic degeneration of seminiferous epithelium indicating suppression of hypophyseal gonadotrophins and proves importance of dopaminergic control over prolactin release for normal functions of male gonad.

Animals↗
PubMed1996

Integration of the DNA of a novel filamentous bacteriophage VSK from Vibrio cholerae 0139 into the host chromosomal DNA.

An unusual filamentous bacteriophage, VSK, containing single-stranded, circular DNA as its genome was isolated from Vibrio cholerae 0139 strains P07 and B04. Unlike other single-stranded DNA phages, VSK can integrate its genome into the chromosome of the host and enter into a lysogenic state. The double-stranded replicative form (RF) of the single-stranded phage DNA was isolated. A restriction map of the VSK RF DNA was constructed using HaeII, AvaII, ClaI and XbaI. By Southern blot analysis of the chromosomal DNA of the lysogen using labeled phage DNA as probe, the attachment site (attP) on the viral genome was also identified.

Bacteriophages↗