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Biomedical subjects

P Prakash

Publications and source records attributed to P Prakash.

At least 91 records · Page 5Linked to original sources
PubMed1975

A note on the quantitative anatomical study of the trachea in the Indian buffalo (Bubalus bubalis).

A quantitative study of the trachea in buffalo has been made. The trachea is found to be about 37.9 +/- 1.8 cm long. It weighs 219.8 +/- 34.08 gm and its capacity is 188.4 +/- 29.3 ml. Its length, weight and capacity appear to be significantly interrelated. The bronchus principalis dexter is found to be diverging at 23.5 degrees +/- 4.6 degrees angle, whereas the bronchus principalis sinister at 34.1 degrees +/- 8.4 degrees. Apart from the first tracheal ring, the trachea has the greatest outer transverse, outer vertical, inner transverse and inner vertical diameters from the fifth to the twentieth tracheal rings. Thereafter, these diameters gradually decrease upto the last tracheal ring, which has the shortest corresponding diameters. The vertical diameter is greater than the transverse diameter throughout the length of the trachea.

Animals↗
PubMedDate not supplied

Interlaboratory interprotocol comparison of indirect immunobead assay for sperm-associated antibodies in serum.

This investigation was designed to study the effect of two different protocols on the indirect sperm-associated antibody test on serum performed using Bio-Rad immunobead (IBT) at two andrology laboratories. Aliquots of 31 serum samples from infertile couples were analyzed by both protocols. The IBT was negative by both protocols (100% concordance) for 18 serum samples. Seven of the 13 remaining samples were positive by both protocols (> or = 10% bead attachment by protocol A and > or = 20% bead attachment by protocol B), for a concordance of 54%. The remaining six samples were positive by one of the two protocols. The overall concordance for positive and negative results was 81% (25 of 31 samples). Protocol A detected a higher percentage of bead attachments for IgG and IgA, while protocol B detected a higher percentage of bead attachments for IgM. The discordance in the results of IgA attachment obtained by the two protocols was statistically significant (p < .05). A standardized, uniform protocol for the indirect IBT is needed.

Autoantibodies↗
PubMedDate not supplied

Strabismus fixus convergens secondary to amyloidosis.

Strabismus fixus convergens is a condition in which both eyes become fixed in extreme adduction. It can be congenital or acquired. We report a case of strabismus fixus convergens in a high myope with primary amyloidosis localized to the lateral rectus muscle. To our knowledge, this is the first report of a case of strabismus fixus convergens secondary to amyloidosis.

Amyloidosis↗
PubMedDate not supplied

Polaroid scotometer: a new device to chart suppression scotomata.

Suppression, an active inhibition of vision in one eye under binocular conditions, is a sensory adaptation in concomitant strabismus. The characteristics and extent of suppression differ not only in different types of strabismus but also in the same type under different testing conditions, which may differ in their degree of dissociation. The findings in exodeviations have thus varied from regional suppression to hemiretinal trigger, and in esodeviations from two point scotoma to single large scotoma. There is a need for a simple but less dissociative test to chart the fields under binocular conditions. We have devised a new, simple instrument based on polaroid dissociation. The findings corroborate the findings of more sophisticated tests like phase-difference haploscope.

Humans↗
PubMedDate not supplied

Cyclic vertical squint.

A rare case of cyclic vertical squint which developed after surgery on medial rectus muscle and its subsequent management by the Faden operation is described.

Adult↗
PubMedDate not supplied

Slow Ca2+ channels neither contribute to upstroke of action potential nor to pacemaker potential in spontaneously active freshly isolated three day embryonic chick ventricle.

Contribution of slow Ca2+ channels to the upstroke of action potential (AP) and pacemaker potential was studied by observing the effects of Ca2+ channel activators- high [Ca2+]0, Bay-K-8644, isoproterenol, forskolin and dibutyryl-cAMP on spontaneous AP of freshly isolated 3 day embryonic chick ventricle (3 day ECV). The spontaneous APs showed maximal upstroke velocity (+Vmax), maximum diastolic potential (MDP), overshoot (Eov) and AP duration at -20 mv (APD20) of 42.60 +/- 2.40 V/sec, -59.05 +/- 0.95 my, 16.30 +/- 0.53 mv and 70.32 +/- 4.60 msec, respectively (an average value of 35 preparations). Bay-K-8644 (0.1-0.8 microM), isoproterenol (5-10 pM) and forskolin (0.1-2.0 microM) induced a concentration-dependent increase in APD20 and Eov without affecting +Vmax. Dibutyryl-cAMP (1 microM) also enhanced the APD20 and Eov and had no effect on +Vmax. Elevation of [Ca2+]0 from 0.6 mM to 9.6 mM caused a concentration-dependent increase in APD20 and Eov leaving +Vmax unaltered. Elevated [Ca2+] and the other Ca2+ channel activators had no significant effect on MDP in above concentration range. Increase in APD20 and Eov could be explained at least by activation of slow Ca2+ channels but the lack of any change in +Vmax clearly suggests that the slow Ca2+ channels do not contribute to the upstroke of AP. All these interventions reduced the rate of spontaneous firing without any noticeable effect on MDP. This finding shows that the slow Ca2+ channels also do not contribute directly to the generation of pacemaker potential in spontaneously active freshly isolated 3 day ECV.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMedDate not supplied

Effect of aniseikonia on fusion.

Physiological aniseikonia is the basis of stereopsis but beyond certain limits it becomes an obstacle to fusion. It is not well established as to how much aniseikonia can be tolerated by the fusional mechanism. Different tests under different testing conditions have given a wide range of variation. On the synoptophore we had observed tolerance upto 35% aniseikonia in some cases. Under more physiological conditions on a polaroid dissociation stereoprojector we observed lesser baseline fusional vergences but tolerance in about 70% of the cases upto 30% aniseikonia while 25% could tolerate even 35% aniseikonia. However we realise that these indicate the maximal potential and not the symptom free tolerable limits.

Aniseikonia↗