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Biomedical subjects

G Krishnan

Publications and source records attributed to G Krishnan.

41 records · Page 3Linked to original sources
PubMedDate not supplied

Expression and characterization of Flag-epitope- and hexahistidine-tagged derivatives of saxiphilin for use in detection and assay of saxitoxin.

Saxiphilin is a plasma protein from the bullfrog (Rana catesbiana) that binds saxitoxin (STX), a causative agent of paralytic shellfish poisoning. Saxiphilin is homologous to transferrin and consists of two internally homologous domains called the N-lobe and the C-lobe. STX binds to a single site in the C-lobe of saxiphilin. In this study, cloned genes coding for recombinant saxiphilin and C-lobe saxiphilin were modified to contain two tandemly located affinity tags, Flag epitope (DYKDDDDK) and His(6) (HHHHHH), at the protein C-terminus and were expressed in cultured insect cells using baculovirus vectors. Both tagged proteins are readily detected on immunoblots by anti-Flag monoclonal antibody. Flag-His(6)-tagged saxiphilin was purified to homogeneity using Ni(2+)-chelate affinity chromatography and Heparin Sepharose chromatography. Equilibrium analysis of [3H]STX binding to tagged saxiphilin and tagged C-lobe saxiphilin gave K(D) values of 0.75 and 2.7 nM, respectively. Flag-His(6)-tagged saxiphilin was also utilized in a microtiter well solid-phase assay with Reacti-bind metal chelate plates to measure [3H]STX binding and binding competition by unlabeled STX. Such Flag-His(6)-tagged derivatives of saxiphilin have many possible applications in the assay of STX and related toxinological research.

Amphibian Proteins↗
PubMedDate not supplied

Cochlear potentials in clinical audiology.

The recording of cochlear and auditory nerve potentials in humans via Electrocochleography (ECochG) has emerged as a valuable tool for a variety of clinical applications. This review consolidates current research on the use of cochlear potentials and ECochG in the clinical setting and identifies several areas in need of additional study. Methodological topics discussed include a review of ECochG recording approaches (i.e. transtympanic versus extratympanic) and issues related to choice of stimuli (clicks versus tonebursts). The review of current applications for cochlear potentials focuses primarily on the use of ECochG in the identification and treatment of Ménière's disease/endolymphatic hydrops (MD/ELH). Other uses for ECochG also are presented (e.g. intraoperative monitoring, enhancement of ABR wave I, estimation of hearing sensitivity). Several suggestions are offered to maximize the predictive value of ECochG in the diagnosis of MD/ELH.

Audiometry, Evoked Response↗
PubMedDate not supplied

A comparison of continuous infusion of vecuronium and atracurium in midline and paramedian laparotomies.

This was a study to compare continuous intravenous infusion of atracurium with continuous intravenous infusion of vecuronium for intraoperative muscle relaxation in 62 ASA I / II patients. Scheduled for laparotomies and pelvic surgeries under general anaesthesia. They were randomly allocated in two groups to receive either vecuronium infusion of 50 microg/kg/hour following a bolus dose of 0.1 microg/kg, or atracurium infusion of 400 microg/kg/hour following a bolus dose of 0.5 microg/kg. The mean infusion dose of atracurium was 478 +/- 44.11 microg/kg/hour and that of vecuronium was 63.2 +/- 74 microg/kg/hour for adequate muscle relaxation. The depth of neuromuscular blockade was monitored by using peripheral nerve stimulator so that only one twitch of train of four was present, resistance to ventilation, surgical relaxation and haemodynamic changes. Vecuronium infusions produced more haemodynamic stability than atracurium infusions. Vecuronium produced lesser change in systolic blood pressure (mean change of 3. 46 +/- 3.33%) from baseline values as compared to atracurium (mean change of 5.81 +/- 3.73%) from baseline values ( p < 0.01) which was statistically significant. The difference in mean pulse rate change from baseline value in the atracurium group (4.78 +/- 2.745%) was less than that in the vecuronium group (5.99 +/- 2.67%), which was not statistically significant. Spontaneous recovery was faster with vecuronium (540.94 +/- 76.46 seconds) as compared to atracurium (596. 33 +/- 72.48 seconds). 84.4% of patients who received vecuronium fell within good to very good category of muscle relaxation as compared to 63.3% in atracurium group. There were no cost benefits when either agents were used in infusion form.

Adolescent↗