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Biomedical subjects

R Arora

Publications and source records attributed to R Arora.

At least 163 records · Page 9Linked to original sources

Double outlet left ventricle with intact ventricular septum: a cross-sectional and Doppler echocardiographic diagnosis.

Double outlet left ventricle with intact ventricular septum, valvar pulmonary stenosis, an atrial septal defect within the oval fossa, dysplastic tricuspid valve and normally related great arteries are described in a four-year old male child presenting with cyanosis since birth. The diagnosis was made by cross-sectional and Doppler echocardiography and confirmed by cineangiocardiography.

Angiocardiography↗

Assessment of mitral valvar stenosis by echocardiography: utility of various methods before and after mitral valvotomy.

Cross-sectional and Doppler echocardiography are currently the most important non-invasive tests for the evaluation of mitral stenosis. Recent experience has, however, shown that parameters that are reliable before mitral valvotomy may not be valid after the procedure. We have studied the validity of estimation of the area of the mitral valve by echo-planimetry, by Doppler pressure half time and the transmitral end-diastolic pressure gradient calculated by continuous wave Doppler in 100 patients (aged 10-30 years) before and after balloon mitral valvoplasty (n = 70) or surgical closed mitral valvotomy (n = 30). These patients underwent cardiac catheterisation and echocardiographic studies before, immediately after and 8-12 (9.3 +/- 2.2) weeks following balloon valvoplasty or closed valvotomy. The area as estimated echocardiographically correlated well with that obtained by the Gorlin formula before (r = 0.80), but not immediately after (r = 0.67) or on follow up after mitral valvotomy. There was good correlation between Doppler pressure half time and the area as estimated by the Gorlin formula before (r = 0.89) and on follow up after valvotomy (r = 0.82), but the correlation was not as good in the immediate period after valvotomy (r = 0.60). The end-diastolic pressure gradients obtained by Doppler examination and at cardiac catheterisation correlated well with each other before (r = 0.94), immediately after valvotomy (r = 0.92) and on follow up (r = 0.94). Hence, the reliability of estimation of the area of the mitral valve by echo-planimetry and by Doppler pressure half time varies according to the time at which the examination is performed following commissurotomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Left ventricular volumes and function immediately after balloon mitral valvoplasty.

To evaluate acute changes in left ventricular volumes and function immediately after successful percutaneous balloon mitral valvoplasty, twenty young patients with isolated rheumatic mitral stenosis (male 9, female 11, mean age 22 +/- 6 years) were studied. The area of the orifice of the mitral valve following valvoplasty, increased from 0.97 +/- 0.27 cm2 to 2.46 +/- 0.75 cm2 (P less than 0.001). No significant change was observed in left ventricular end-diastolic volumes (117 +/- 27 ml to 119 +/- 29 ml, P greater than 0.10), end-systolic volumes (51 +/- 21 ml to 50 +/- 20 ml, P greater than 0.10), ejection fraction (0.57 +/- 0.10 to 0.58 +/- 0.10, P greater than 0.10) and left ventricular meridian wall stress (68 +/- 20.10(3) dynes/cm2 to 65 +/- 14, P greater than 0.10) immediately after valvoplasty. There was no acute change in heart rate, left ventricular end-diastolic pressure, cardiac index and grade of mitral regurgitation. Patients with depressed left ventricular ejection fraction (less than or equal to 0.55, n = 10) and those with normal ejection fraction (greater than 0.55, n = 10) had similar baseline left ventricular end-diastolic volumes and showed no significant change in volumes and ejection fraction after the procedure, although the former group had a greater orificial area after valvoplasty (P less than 0.05). We conclude that an acute increase in the orifice of the mitral valve in patients with rheumatic mitral stenosis is not associated with any significant change in left ventricular volumes and function.

Adolescent↗

In vivo effects of nonionic and ionic contrast media on beta-thromboglobulin and fibrinopeptide levels.

Nonionic contrast media are suggested to cause increased thromboembolism (in vivo), platelet aggregation and procoagulant effect (in vitro) as compared with ionic contrast media. To study these effects in vivo, 30 consecutive patients undergoing routine angiography were prospectively randomized to three groups of 10 patients each. Group A received diatrizoate (ionic, high osmolality), Group B ioxaglate (ionic, low osmolality) and Group C iohexol (nonionic, low osmolality). In vivo platelet alpha-granule release and fibrin-1 formation were measured by radioimmunoassay of beta-thromboglobulin and fibrinopeptide A in peripheral venous samples. Levels were estimated at three stages during the procedure: before and after left ventriculography and after coronary angiography. No differences were noted (p = NS) when the ratios of beta-thromboglobulin and fibrinopeptide A were compared among the three groups. These data suggest that the newer nonionic contrast media do not demonstrate enhanced systemic platelet activation or fibrin formation as compared with standard ionic contrast media. However, larger randomized clinical studies are necessary to conclusively establish the suggested thromboembolic potential of nonionic contrast media.

Angiography↗

Peribulbar anesthesia and optic nerve conduction.

Serial recordings of distance visual acuity and visually evoked potentials (VEPs) after peribulbar anesthesia in three patients are reported. Visual acuity was not markedly affected but the latency and amplitude of VEPs were. This study concludes that optic nerve conduction is not significantly affected by peribulbar anesthesia.

Adolescent↗

A loss in the plasma membrane ATPase activity and its recovery coincides with incipient freeze-thaw injury and postthaw recovery in onion bulb scale tissue.

Plasma membrane ATPase has been proposed to be functionally altered during early stages of injury caused by a freeze-thaw stress. Complete recovery from freezing injury in onion cells during the postthaw period provided evidence in support of this proposal. During recovery, a simultaneous decrease in ion leakage and disappearance of water soaking (symptoms of freeze-thaw injury) has been noted. Since reabsorption of ions during recovery must be an active process, recovery of plasma membrane ATPase (active transport system) functions has been implicated. In the present study, onion (Allium cepa L. cv Downing Yellow Globe) bulbs were subjected to a freeze-thaw stress which resulted in a reversible (recoverable) injury. Plasma membrane ATPase activity in the microsomes (isolated from the bulb scales) and ion leakage rate (efflux/hour) from the same scale tissue were measured immediately following thawing and after complete recovery. In injured tissue (30-40% water soaking), plasma membrane ATPase activity was reduced by about 30% and this was paralleled by about 25% higher ion leakage rate. As water soaking disappeared during recovery, the plasma membrane ATPase activity and the ion leakage rate returned to about the same level as the respective controls. Treatment of freeze-thaw injured tissue with vanadate, a specific inhibitor of plasma membrane ATPase, during postthaw prevented the recovery process. These results indicate that recovery of freeze-injured tissue depends on the functional activity of plasma membrane ATPase.

Journal Article↗

Effect of Macerase, Oxalic Acid, and EGTA on Deep Supercooling and Pit Membrane Structure of Xylem Parenchyma of Peach.

The object of this study was to determine if calcium cross-linking of pectin in the pit membrane of xylem parenchyma restricts water movement which results in deep supercooling. Current year shoots of ;Loring' peach (Prunus persica) were infiltrated with oxalic acid or EGTA solutions for 24 or 48 hours and then either prepared for ultrastructural analysis or subjected to differential thermal analysis. The effect of 0.25 to 1.0% pectinase (weight/volume) on deep supercooling was also investigated. The use of 5 to 50 millimolar oxalic acid and pectinase resulted in a significant reduction (flattening) of the low temperature exotherm and a distinct swelling and partial degradation of the pit membrane. EGTA (10 millimolar) for 24 or 48 hours shifted the low temperature exotherm to warmer temperatures and effected the outermost layer of the pit membrane. A hypothesis is presented on pectin-mediated regulation of deep supercooling of xylem parenchyma.

Journal Article↗

Nyctalopia.

Explore the source record for details and available documents.

Child↗

Left ventricular mass in normal adult Indians & its correlation with anthropometric parameters.

Important differences were found to exist between male and non-pregnant female Indian adults in the echocardiographically determined left ventricular mass (170.58 +/- 51.91 g vs 131.14 +/- 42.84 g, P less than 0.001) and relationship of left ventricular mass (LVM) to age, body weight, height, body surface area (BSA) and body mass index (BMI). In males, LVM has a fair to good correlation with age, body weight, height, BSA and BMI (P less than 0.001). However, in female subjects, LVM correlates modestly with age, weight, BSA, BMI (P less than 0.01) but not with height. LVM can be best expressed by indexing to body weight in both sexes, but differences persist when other anthropometric parameters are used as denominators.

Adult↗

Pediatric hypertension: clinical profile and etiology.

Thirty six symptomatic hospitalized hypertensive children were evaluated for clinical profile and etiology. They were divided into two groups of 23 and 13 patients, respectively of chronic persistent hypertension and acute transient hypertension. Headache, failure to thrive, dyspnea and edema were common clinical features. Renal parenchymal pathology was the commonest etiology in both groups with a tubulo-interstitial pathology being more common amongst chronic hypertensives and acute glomerulonephritis in acute transient hypertensives. Essential hypertension was uncommon, found in only two patients with chronic hypertension reflecting probably an asymptomatic status of most patients with essential hypertension.

Child↗

Side chain conjugation prevents bacterial 7-dehydroxylation of bile acids.

The effect of side chain conjugation on 7-dehydroxylation of bile acids has been investigated. C24-bile acids and their glycine and taurine conjugates and keto bile acids were incubated with pure strains of Eubacterium sp. VPI 12708. Bile acids of the 5 alpha- or 5 beta-series with a free terminal carboxyl group and a 3 alpha, 7 alpha-dihydroxy system were very effectively 7 alpha-dehydroxylated, whereas 7 beta-hydroxy bile acids resisted 7-dehydroxylation. Oxo bile acids were metabolized at the oxygen function also. Glycine- and taurine-conjugated bile acids were neither deamidated nor 7-dehydroxylated by the bacteria. Thus, side chain conjugation prevents 7-dehydroxylation of bile acids by Eubacterium sp. VPI 12708.

Bile Acids and Salts↗

Unusual thrombi in the setting of rheumatic heart disease.

We report two patients with unusual intracavitary thrombi in association with rheumatic mitral stenosis. One patient had a large free-floating left atrial thrombus immediately after successful closed mitral valvotomy causing recurrent acute pulmonary oedema in the post-operative phase. The other patient was detected to have multiple, discrete and calcified left ventricular thrombi in the presence of severe left ventricular systolic dysfunction. The diagnosis in both cases was made by cross-sectional echocardiography.

Adult↗

Contribution of atrial contraction to left ventricular filling in patients with sick sinus syndrome on AAI pacing.

Doppler echocardiographic evaluation of the contribution of atrial contraction to left ventricular filling, its determinants and relationship with early diastolic filling was studied in 20 patients with sick sinus syndrome without structural heart disease on AAI pacing over a wide range of physiological atrioventricular delays (PR intervals). The results were compared with 20 normal controls matched for age, sex and heart rate. Left ventricular filling pattern, and the contribution of left atrial contraction to diastolic filling, were similar in the two groups. AAI pacing restores the physiological dynamics of left ventricular filling in patients with sick sinus syndrome without organic heart disease.

Cardiac Pacing, Artificial↗