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Biomedical subjects

V K Das

Publications and source records attributed to V K Das.

At least 19 recordsLinked to original sources
PubMed2002

Enlarged vestibular aqueduct in two male siblings.

This report describes the case history of two male siblings with sensorineural hearing loss and an enlarged vestibular aqueduct (EVA). Sibling 1 presented with a history of intermittent self-limiting ataxia and hearing loss at the age of 25 months and sibling 2 presented with a similar history at the age of 18 months. MRI showed an enlarged endolymphatic duct and sac bilaterally in both children. Perchlorate discharge tests were positive in both infants leading to a diagnosis of Pendred syndrome. A number of conditions associated with EVA are discussed with a view to devising management strategies.

Child, Preschool↗
PubMed1998

Morphological and functional aspects of reptilian ultimobranchial gland.

The intention of this review is to compare studies on the morphology and histology (light and electron microscopic) of ultimobranchial glands of various groups of reptiles. Moreover, experiments (including our investigations) on suppression or stimulation of the ultimobranchial gland are included. Adult reptiles possess one (on the left side) or two ultimobranchial glands (UBG). The UBG lie just anterior to the heart. Light as well as electron microscopically, the gland has been shown to contain follicles and cell cords (cell aggregates). The follicular epithelium is lined by simple cuboidal or pseudostratified columnar cells. Ciliated and goblet cells may be present in the follicular epithelia in some groups. The lumen may contain a colloid-like substance with desquamated cells or debris. The UBG of reptiles seem to be an active secretory organ with influence on calcium regulation. Other functions of calcitonin have also been suggested in reptiles for example in neurotransmission, in volume regulation, phosphate balance and promotion of bone calcification (at least in juveniles).

Alligators and Crocodiles↗
PubMed1997

Chronic toxicity of propoxur on carbohydrate, protein and serum electrolyte levels in catfish, Heteropneustes fossilis.

Alterations in the biochemical parameters of the catfish treated with low sublethal concentration (2.15 mg.L-1; 1/3 of 96 h LC50) of a carbamate pesticide-propoxur under static laboratory conditions for 10, 20 and 30 days were assayed. The fish elicited consistent hyperglycemia, concomitant with liver and muscle glycogenolysis, and hypoproteinemia in muscle and liver except 10 day post exposure to the pesticide, where hyperproteinemia was noticed in the liver. Throughout the exposure period the fish exhibited hyperphosphatemia. Hypocalcemia were recorded after 20 and 30 days, and serum magnesium level increased significantly only at 30 day exposure to the pesticide.

Animals↗
PubMed1996

Audio-vestibular manifestations of Chiari malformation and outcome of surgical decompression: a case report.

Sensorineural hearing loss, tinnitus, dizziness and ataxia are recognised symptoms associated with Chiari malformations but they are rarely the presenting complaints. Patients with such symptoms are frequently referred to otolaryngologists and audiological physicians. We report a case of a 13-year-old girl who presented complaining of tinnitus and impaired hearing, and was subsequently diagnosed as having a type I Chiari malformation. Pure tone audiogram showed a mild hearing impairment on the left side and the speech audiogram was normal. Auditory brain stem responses and the electronystagmography were abnormal. The patient underwent posterior fossa decompression following which her tinnitus disappeared, the hearing problem recovered and some of the abnormal electrophysiological parameters were corrected.

Adolescent↗
PubMed1996

Aetiology of bilateral sensorineural hearing impairment in children: a 10 year study.

The study was carried out on children born over a 10 year period from 1981 to 1990 in a defined area known as Greater Manchester and referred to the Centre for Audiology or the Manchester Royal Infirmary for specialist audiological assessment. The children were investigated for possible congenital or intrauterine infection. Perinatal assessment was carried out in conjunction with paediatricians for adverse aetiological factors. Full medical histories were obtained with detailed family history relevant to hearing impairment and any associated condition or syndrome. Parents and siblings were examined and hearing assessed. A total of 339 cases was studied. Children with positive family history of deafness in parents or siblings, or both, constituted 23.3% of the cases (genetic group). Other aetiological groups showed the following distribution: cause unknown 33.9%; perinatal group 12.8%; congenital infections 8.2%; bacterial meningitis 6.5%; chromosomal anomalies 5.3%; syndromal group 5.3%; and miscellaneous group 4.7%. The high incidence of genetic causes indicates that steps should be taken to facilitate genetic counselling and conceivably to reduce the numbers affected.

Age Factors↗
PubMed1995

Amphibian parathyroids: morphological and functional aspects.

Amphibians living partially or totally in a terrestrial environment are the first tetrapods to possess parathyroid glands. Purely aquatic amphibians and amphibian larvae lack these endocrine glands. The parathyroids develop at the time of metamorphosis. The parathyroid glands in caecilians consist of a single cell type, that of urodeles may be composed of basal (supporting) cells and suprabasal (chief) cells, and that of anurans of small and large chief cells. Parathyroid glands of caecilians and anurans lack connective tissue, blood vessels, and nerves. The parathyroid cells become activated in response to decreased blood calcium concentration and undergo changes indicating increased parathyroid hormone secretion. Increased blood calcium concentration suppresses secretory activity. Usually, parathyroidectomy elicits hypocalcemia in most amphibians. Such operations have no effect in lower urodeles. Parathyroid hormone administration provokes hypercalcemia in most amphibians. The parathyroids of caecilians have not been studied in detail. The urodeles and anurans exhibit seasonal changes in the parathyroid glands. These changes may be initiated by environmental stimuli such as light, temperature, or alterations in blood calcium levels caused by natural hibernation.

Animals↗
PubMed1994

Effects of adverse perinatal events on hearing.

The hearing sensitivity for frequencies 8 kHz through to 18 kHz was compared between children with adverse perinatal factors (study group) and children without adverse perinatal factors (control group). Children in both groups had hearing at levels of 20 dB HL or better in the frequency range between 250 Hz to 8 kHz with normal middle ear pressure. High frequency hearing tests showed that the mean high frequency hearing threshold levels were worse in the study group. Statistical analysis showed significant differences in hearing levels at and above 12 kHz frequencies between the study and control groups. The hearing levels were found to be more significantly affected in females as compared to males, indicating that the high frequency hearing of females was more vulnerable to damage. The results indicate that adverse perinatal events are associated with raised high frequency thresholds in both sexes, especially in females.

Acoustic Impedance Tests↗
PubMed1992

Dose-dependent vitamin D3, 25-hydroxyvitamin D3 and 1,25-dihydroxyvitamin D3-induced hypercalcemia and hyperphosphatemia, and the correlative changes in the activity of ultimobranchial and parathyroid glands of the toad, Bufo andersoni Boulenger.

Vitamin D3, 25(OH) vitamin D3 and 1,25 (OH)2D3 were administered daily to unfed male Bufo andersoni for 15 days which resulted in a significant hypercalcemia and hyperphosphatemia in a dose-dependent fashion. 1,25(OH)2D3 is more potent than the other metabolites. The treatment activated ultimobranchial gland but induced degenerative changes in parathyroid of the toads.

Animals↗
PubMed1991

Adverse perinatal factors in the causation of sensorineural hearing impairment in young children.

The study involves aetiological evaluation of various adverse perinatal causes leading to bilateral sensorineural hearing impairment in children born during the 5-year period of 1981-1985 (inclusive) in the Greater Manchester area of England, United Kingdom. This group comprised over 12% of the total number of hearing-impaired children in the area. Individual possible adverse factors are discussed in the light of present understanding of the pathogenesis and previous reports.

Audiometry, Evoked Response↗
PubMed1990

Prevalence of otitis media with effusion in children with bilateral sensorineural hearing loss.

A cohort of 164 children born within the defined boundaries of greater Manchester during the years 1981 to 1984 inclusive were identified as having bilateral sensorineural hearing loss, giving a prevalence of 1.2/1000 population of 1/817 births. Ninety three children developed an additional conductive hearing loss secondary to otitis media with effusion lasting more than three months and 39 of these (42%) required surgical treatment. Those with congenital infections, adverse perinatal factors, and chromosomal abnormalities seemed to develop more conductive hearing problems than those in whom the aetiology was infective. Close audiology follow up is essential for effective treatment of children with sensorineural hearing loss.

Child↗
PubMed1988

Aetiology of bilateral sensorineural deafness in children.

The study was carried out in children born during the four year period 1981-1984 in the Greater Manchester County. The children were investigated for possible congenital infections. Perinatal assessment was carried out for adverse aetiological factors. Family histories were obtained and parents and siblings were examined for any hearing impairment. A total of 164 cases were investigated. Various aetiological groups were formed which showed the following distribution: cause unknown 36.5 per cent; genetic group 20.1 per cent; adverse perinatal factors 14.6 per cent; congenital infections 9.8 per cent; meningitis 6.1 per cent; chromosomal abnormalities 3.7 per cent; syndromal group 3.7 per cent; and miscellaneous 5.5 per cent. The findings are discussed in the light of previous studies.

Child↗
PubMed1988

Aetiology of bilateral sensori-neural deafness in children.

The study was carried out in the Department in children born during the four year period 1981-1984 in a well defined geographical areas known as the Greater Manchester County. The children were investigated for possible congenital infections. Perinatal assessment was carried out in conjunction with the Paediatricians for aetiological adverse factors. Family histories were obtained and parents and siblings were examined for any hearing impairment. A total of 155 cases were investigated. Cases with a positive family history with deafness in siblings or parents constituted 18.7% of cases. An even larger group (35.5%) was found to have no known positive cause and negative family history. Adverse perinatal factors accounted for 15.5% of cases while congenital infections were found to be the cause of deafness in 10.3%. Meningitis led to deafness in 6.5% and chromosomal abnormality was the aetiological factor in 3.8% of cases.

Child↗
PubMed1987

Pendred's syndrome with episodic vertigo, tinnitus and vomiting and normal bithermal caloric responses.

A case of early-onset bilateral sensori-neural deafness with episodic objective vertigo, tinnitus and vomiting, suggestive of Menière's syndrome, was found to have a diffuse goitre. A Perchlorate discharge test was positive, indicating an organification defect diagnostic of Pendred's syndrome. The case was found to be euthyroid both clinically and on investigations. Tone decay was absent and recruitment was found, thus indicating a cochlear site of lesion. Bithermal caloric tests and clinical tests of vestibular function were within normal limits. X-rays, including petrous tomography, did not show any abnormalities.

Audiometry↗
PubMed1986

Vitamin D2-induced hypercalcemia in rat lens.

Vitamin D2 (40,000 IU) per 100 g body weight was administered daily in male albino rats. The levels of calcium and inorganic phosphate were determined in serum and lens. Lens calcium was elevated in the treated rats by 40%.

Animals↗