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Biomedical subjects

S Prabhakar

Publications and source records attributed to S Prabhakar.

At least 55 records · Page 3Linked to original sources

Possible relationship between phenylthiocarbamide taste sensitivity and epilepsy.

The study was based on the data of a sample of 400 epileptic patients (200 idiopathic and 200 symptomatic) and 100 normal healthy individuals serving as controls. The PTC threshold distribution was bimodal. The number of non-tasters among idiopathic epileptics (35.5%) and symptomatic epileptics (32.5%) was significantly higher than controls (20%). The relative incidence of non-tasters in idiopathic and symptomatic epilepsies was 2.20 and 1.93 respectively. There is evidence that non-tasters tend to ingest a greater quantity of bitter tasting goitrogenic substances present naturally in edible plants which in turn exert greater thyroid stress in non-tasters or less sensitive tasters. Such a stress during intrauterine or early childhood growth and development might have affected neurological maturation which in turn made them more susceptible to epilepsy than tasters, who faced lesser stress.

Adolescent↗

Low prevalence of progressive multifocal leukoencephalopathy in India and Africa: is there a biological explanation?

Infection with human immunodeficiency virus (HIV) clade C virus is the most common form of HIV infection in the world. It largely infects populations in Africa and Asia and not much is known about the neurological complications associated with the virus. Cases of progressive multifocal leukoencephalopathy (PML) have been rarely reported in the literature in the acquired immunodeficiency syndrome (AIDS) or non-AIDS populations from these regions. In this article, the authors present three recently diagnosed patients with AIDS and PML from one neurological center in India, review the diagnostic challenges faced, and speculate on the possible biological reasons, including viral strain differences as well as HIV and JC virus interactions, that may account for the low incidence.

Acquired Immunodeficiency Syndrome↗

Ventilatory management of respiratory failure in patients with severe Guillain-Barre syndrome.

Guillain-Barre syndrome (GBS) is the commonest peripheral neuropathy causing ventilatory failure, and 10-30% patients may require respiratory support. Records of 11 adult patients of GBS in respiratory failure, admitted to the Respiratory Intensive Care Unit (RICU) of our institute for mechanical ventilation over a four-year period, were studied. Six patients received intravenous immunoglobulin. The median duration of mechanical ventilation was 38 days. Seven patients underwent tracheostomy. Four patients were ventilated for less than 2 weeks and 3 for more than 2 months each. Seven developed ventilator-associated pneumonia and/or sepsis. Three patients died in, and two shortly after discharge from RICU; all had systemic problems or complications of hospitalization.

Adolescent↗

Enhancing reproductive performance in dairy buffalo: major constraints and achievements.

Buffalo are of high economic importance for farmers in several developing countries but reproductive performance is poor. A large proportion of heifers attain puberty at 3-5 years of age. A good quality diet supplemented with extra nutrients reduces the age of puberty, whereas the effects of administration of exogenous GnRH or equine chorionic gonadotrophin (eCG) are equivocal. The incidence of anoestrus in buffalo ranges from 20 to 80% depending on season. Most buffalo cease ovarian cyclicity during hot summers probably due to the combined effects of nutrition, environment and management. Keeping buffalo cool by wallowing, water sprinklers or shade improves fertility. Supplementary feeding with Urea Molasses Multi-nutrient Blocks (UMMB) for 60 days before calving enhances the early onset of postpartum oestrus. Regular UMMB supplementation also improves pregnancy rates in anoestrous non-pregnant buffalo. Prepartum vaginal prolapse is hereditary and eradication can be achieved by genetic selective breeding programmes. Treatment with calcium, phosphorus and progesterone gives only transient relief to clinical cases. Uterine torsion is the most common cause of dystocia (70%). Deployment of Sharma's detorsion method and anti-stress measures increase survival rates in cases presented within 36 h. In conclusion, greater understanding about the effects of better year-round nutrition, improved management and markers for logical breeding programmes are essential to curtail the incidence of the reproductive disorders that reduce buffalo fertility.

Animal Nutritional Physiological Phenomena↗

Management of agitation and convulsions in hepatic encephalopathy.

Hepatic encephalopathy represents a reversible decrease in neurological function caused by liver disease. Overall incidence of seizures in hepatic encephalopathy varies between 2% and 33%. Non-convulsive status epilepticus may be particularly common in these patients. Psychiatric disturbances manifest as agitation, personality change, delusions, etc. Aims of seizure management include treatment of basic disease, correction of precipitant factors, imaging of head, and choice of a pharmacologically safe agent. It is important to consider non-convulsive status epilepticus and rule it out by an EEG. Absolute data for safety profile of drugs in liver disease is still not clear, as changes of pharmacokinetics make choice of drugs difficult. Free drug concentrations may be higher, making plasma concentration monitoring essential in such circumstances. A single seizure may not require therapy. However when started, antiepileptic drugs are usually discontinued early. Drugs with sedative effects are best avoided because of a risk of precipitating coma. Phenytoin and gabapentin are relatively preferred drugs; however, monitoring of drug levels is desirable. Management of agitation includes physical restraint and medication. Benzodiazepines are best avoided. Haloperidol is a safer choice in the presence of liver disease. Overall management of neuropsychiatric state aims at management of underlying pathology, the resolution of which leads to improvement in the clinical symptomatology.

Hepatic Encephalopathy↗

Adsorption of oleic acid at sillimanite/water interface.

The interaction of oleic acid at sillimanite-water interface was studied by adsorption, FT-IR, and zeta potential measurements. The isoelectric point (IEP) of sillimanite obtained at pH 8.0 was found to shift in the presence of oleic acid. This shift in IEP was attributed to chemisorption of oleic acid on sillimanite. Adsorption experiments were conducted at pH 8.0, where the sillimanite surface is neutral. The adsorption isotherm exhibited a plateau around 5 micromol/m2 that correspond to a monolayer formation. Adsorption of oleic acid on sillimanite, alumina, and aluminum hydroxide was studied by FT-IR. Chemisorption of oleic acid on the above substrates was confirmed by FT-IR studies. Hydroxylation of mineral surface was found to be essential for the adsorption of oleic acid molecules. These surface hydroxyl sites were observed to facilitate deprotonation of oleic acid and its subsequent adsorption. Thus protons from oleic acid react with surface hydroxyl groups and form water molecules. Based on the experimental results, the mechanism of oleic acid adsorption on mineral substrate was proposed. Free energy of adsorption was estimated using the Stern-Graham equation for a sillimanite-oleate system.

Journal Article↗

Planococcus antarcticus and Planococcus psychrophilus spp. nov. isolated from cyanobacterial mat samples collected from ponds in Antarctica.

Thirteen orange-pigmented bacteria associated with cyanobacterial mat samples collected from four different lakes in McMurdo, Antarctica, were isolated. Twelve of the isolates, which were coccoid in shape, were very similar and possessed all the characteristics of the genus Planococcus and represented a new species, which was assigned the name Planococcus antarcticus sp. nov. (CMS 26or(T)). Apart from the phenotypic differences, P. antarcticus differed from all reported species of Planococcus by more than 2.5% at the 16S rRNA gene sequence level. In addition, at the DNA-DNA hybridization level, it exhibited very little similarity either with P. mcmeekinii (30%-35%), P. okeanokoites (26%-29%), or CMS 53or(T) (15%-25%), the three species with which it is closely related at the rRNA gene sequence level (2.5%-2.9%). P. antarcticus also showed only 2.5% difference in its 16S rRNA gene sequence compared with the P. alkanoclasticus sequence. But it was distinctly different from P. alkanoclasticus, which exists only as rods, is mesophilic and phosphatase positive, can hydrolyze starch, cannot utilize succinate, glutamate, or glucose, and cannot acidify glucose. Most important, P. antarcticus and P. alkanoclasticus varied distinctly in their fatty acid composition in that C(15:0), C(15:1), C(16:0), iso-C(16:1), and C(17:0) were present only in P. antarcticus but absent in P. alkanoclasticus. CMS 53or(T), the thirteenth isolate, was also identified as a new species of Planococcus and was assigned the name Planococcus psychrophilus sp. nov. This species was distinctly different from all the reported species, including the new species P. antarcticus, with respect to a number of phenotypic characteristics. At the 16S rRNA gene sequence level, it was closely related to P. okeanokoites (98.1%) and P. mcmeekinii (98%), but with respect to the DNA-DNA hybridization, the similarity was only 35%-36%. The type strain of P. antarcticus is CMS 26or(T) (MTCC 3854; DSM 14505), and that of P. psychrophilus is CMS 530r(T) (MTCC 3812; DSM 14507).

Antarctic Regions↗

Pattern of use of complementary/alternative medicine (CAM) in epileptic patients in a tertiary care hospital in India.

PURPOSE: Many patients use complementary/alternative medicine (CAM) for their health problems especially where long-term treatment is required. Epilepsy is the most prevalent neurological disorder requiring long-term treatment and compliance. The purpose of the study was to establish the pattern of use of CAM in epileptic patients. METHODS: 1000 patients with seizure disorder visiting the Neurology outpatient department were interviewed regarding use of complementary/alternative medicine (CAM) in the past. The pattern of use, persons who recommended CAM and the reasons for trying these therapies and sequence of seeking them was noted in these patients. RESULTS: Overall 32% of patients had used CAM. Ayurvedic medicine was used most frequently, either alone (43%) or in combination (38%) with other CAM therapies followed by homeopathy (12.5%). Use of CAM was seen among all age groups and at all levels of education and was most frequent in the rural population (67%). Influence of family and friends (50%) was the most common reason for trying these therapies. Most patients (57%) sought CAM providers first before seeking the services of a medical doctor in our study. CONCLUSION: As more and more patients use CAM, physicians should ask their patients whether they use these therapies and should discuss these practices with their patients in order to safeguard their health.

Adolescent↗

Crack detection by measurement of mechanical impedance of a rotor-bearing system.

Measurements were done to determine the influence of a transverse crack on the mobility of a rotor-bearing system. The results show that the mobility changes substantially due to the presence of crack and follows definite trends with the crack depth and direction of force application. The significant changes in mobility were observed at the natural frequency and at the running frequency of the rotor system. Good agreement between the experimental results and numerical simulations has been observed. The measurement of mobility has been suggested for crack detection and condition monitoring of rotor-bearing systems.

Journal Article↗

Hypertrophic pachymeningitis: varied manifestations of a single disease entity.

Hypertrophic pachymeningitis is a unique clinical entity characterised by fibrosis and thickening of the duramater with resulting neurological dysfunction. Three cases of this entity are described. Presenting features were headaches and cranial neuropathies in two patients and predominantly cerebellar dysfunction in the third. One of the patients also had evidence of spinal involvement. Lower cranial nerves were chiefly involved in two patients whereas optic nerve was the predominantly affected nerve in one. Except for the presence of rheumatoid arthritis in one of the patients, we could not document clinical or biochemical evidence of any predisposing infective, inflammatory or infiltrative condition in the other two. All three patients had characteristic changes on imaging suggestive of thickened and enhancing duramater. Although variable steroid responsiveness was seen in all the three patients, tendency towards steroid dependence was evident. The clinical presentations, causes, radiological features, management options and differential diagnosis of this unique clinical syndrome have been discussed.

Central Nervous System Diseases↗

A case of emotional facial palsy with ipsilateral anterior inferior cerebellar artery territory infarction.

Emotional facial palsy (EFP) commonly results from anterolateral thalamic or striatocapsular infarcts. Its occurrence in brainstem lesions is uncommon, with previously reported cases being restricted to superior cerebellar artery infarction (3 cases). We report an unusual case of EFP ipsilateral to an anterior inferior cerebellar artery infarction, which opens new insights into the facial corticobulbar tract pathway.

Adult↗

Acute symptomatic seizures due to single CT lesions: how long to treat with antiepileptic drugs?

The duration of anti epileptic drug therapy for single small enhancing CT lesions (SSECTL) presents a major dilemma. We studied the efficacy of short duration (6 months) antiepileptic drug therapy as compared to long duration (2 years) drug therapy. Seventy three patients presenting with seizures and showing SSECTL on cranial CT scans (plain and contrast) were randomized into group A (6 months therapy) and group B (2 years therapy). There were 47 patients in group A and 26 patients in group B. Patients were followed up for one year after withdrawal of anti epileptic drugs. CT Head (plain and contrast) was repeated after 3 months, or earlier in cases of recurrence to rule out reinfection. 53.2% in group A and 53.8% in group B showed complete resolution and were seizure free on one year follow up. Punctate residual calcification was seen in 46.8% in group A and 46.2% in group B. Eight patients (17%) in group A and three (11.5%) in group B had a recurrence. The difference in recurrence of seizure between the two groups was not statistically significant (p<0.77) in the calcified lesion subset. Since none of the patients in total resolution subset showed recurrence, the difference between calcified and total resolution subset was highly significant. The study shows that a short duration (6 months) AED therapy in patients with total resolution of lesion on follow up scan, may be adequate in comparison to those who have calcific speck as a residue. However, a longer duration of therapy in case of calcific group probably does not alter their chances of recurrence.

Acute Disease↗

Intensive respiratory care in patients with myasthenic crisis.

Six patients received mechanical ventilation for 8 episodes of myasthenic crisis in a two year period. Median duration of ventilation was 8 days. Only one patient required ventilation for more than three weeks and underwent tracheostomy. Atelectasis and pneumonia were the common ventilator associated complications observed, and these responded to therapy. Two patients underwent thymectomy after initial stabilization and while being ventilated. All patients recovered completely.

Adolescent↗