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Biomedical subjects

Vinod Kumar Gupta

Publications and source records attributed to Vinod Kumar Gupta.

31 records · Page 2Linked to original sources
PubMed2005

Strontium(II) sensor based on a modified calix[6]arene in PVC matrix.

5,11,17,23,29,35-Hexakis(1,1,3,3-tetramethylbutyl)-37,38,39,40,41,42-hexakis(carboxy methoxy)calix[6]arene (I) has been evaluated as an ionophore for the analysis of Sr2+. The influences of the nature of the plasticizers (DBA, CN, DOP, NPOE) and of the anion excluder (NaTPB) on the characteristics of the electrode were discussed. The best electrode was fabricated with a membrane having composition 6:150:170:3 (I:PVC:DBA:NaTPB). The response to Sr2+ was Nernstian in the range 1.9 x 10(-5) to 1.0 x 10(-1) M of Sr2+. The influence of pH has also been studied. The electrode exhibited better potential stability and had an operational lifetime of 4 months. The K(A,B)(Pot) values showed that other alkaline earth metal ions are well discriminated. The sensor has also been used as an indicator electrode in the potentiometric titration of sodium carbonate with strontium(II) ions.

Calixarenes↗
PubMed2004

Is benign cough headache caused by intraocular haemodynamic aberration?

Rise of intracranial pressure (ICP) is currently presumed to underlie benign cough headache (BCH). Cough normally increases ICP but very few patients develop BCH. Children, young adults and females are rarely affected. Reduction of ICP by lumbar puncture (LP) or indomethacin offers variable therapeutic success. BCH can persist for several months or years but LP lowers ICP for few hours only and has significant morbidity. Choroidal blood volume and intraocular pressure (IOP) are instantaneously responsive to cough. Mechanical deformation of pressure-sensitive ocular structures by sudden experimental IOP elevation generates transient neural traffic in ocular trigeminal nerve fibres. Homeostatic mechanisms normally limit effect of cough-induced intraocular venous congestion. I propose that in a few patients, ocular sympathetic hypofunction significantly alters intraocular pressure-volume relation and predisposes to exaggerated choroidal venous congestion and fluctuation of IOP in response to cough, that, in turn, results in sudden transient cephalalgogenic antidromic trigeminal nerve discharge. Known variations in ocular hydrodynamics, ocular rigidity, and forced expiration rationalize epidemiology of BCH. This hypothesis can be tested by study of pupillary function and facial sweating in patients with BCH.

Disease Susceptibility↗
PubMedDate not supplied

Botulinum toxin--a treatment for migraine? A systematic review.

Scalp injection of botulinum toxin type A (BT-A) into the superficial musculature has evoked interest in the management of migraine headache. In clinical trials, prevention of migraine attacks for 3 months or more has been seen in some patients following BT-A scalp injections. In the majority of pain syndromes where BT-A is effective, inhibition of muscle spasms appears to be an important component of its activity. A direct or independent and prolonged analgesic action unrelated to skeletal muscle relaxation is believed to underlie the prophylactic efficacy of BT-A in migraine; peripheral and central modulation of pain impulses by BT-A has also been proposed. A direct peripheral antinociceptive effect was not seen in three controlled studies of BT-A in normal human volunteers. Experimental evidence for BT-A-induced analgesia in rats is suggestive but dose-dependent and lasts only 2 weeks. In migraine patients, a consistent or dose-dependent response to BT-A treatment has not been seen. Peak responses to BT-A in migraine patients are seen at 8-12 weeks, whereas BT-A-affected nerve endings in mice fully recover function between 63 and 91 days; the difference in species limits the interpretation of this dissonance. As BT-A does not normally cross the intact blood-brain barrier, meningeal nociceptors appear unlikely to be influenced by scalp injections of BT-A; the possibility of antidromic transfer of BT-A in the trigeminovascular system should be considered. The extended period for which migraine prophylaxis might be required, the antigenic and headache-provoking potential of BT-A, the inability of BT-A to affect central neuronal processes significantly, including the aura of migraine, the possible placebo effect of needling, and purely subjective outcome measures in headache studies are additional concerns in evaluating this treatment strategy. The clinical utility of BT-A has not been compared against established migraine prophylactic agents. The efficacy of BT-A in preventing migraine headache attacks remains controversial and the underlying scientific rationale is debatable.

Animals↗