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Biomedical subjects

R Arora

Publications and source records attributed to R Arora.

At least 19 recordsLinked to original sources
PubMed1992

Pulmonary venous flow dynamics before and after balloon mitral valvuloplasty as determined by transesophageal Doppler echocardiography.

The pattern of left atrial filling was studied in 14 patients with severe mitral stenosis in sinus rhythm before and immediately after successful balloon mitral valvuloplasty by transesophageal pulsed Doppler echocardiography of the left superior pulmonary vein. Mean mitral valve orifice area increased from 0.8 +/- 0.1 to 2.2 +/- 0.3 cm2 (p less than 0.0001), and left atrial mean pressure decreased from 30 +/- 5 to 12 +/- 4 mm Hg (p less than 0.0001) after the procedure. After balloon mitral valvuloplasty, significant increases in peak systolic pulmonary velocity (35 +/- 16 to 44 +/- 10 cm/s; p less than 0.01), systolic flow velocity time integral (3.3 +/- 1.5 to 5.9 +/- 2.0 cm; p less than 0.001) and the ratio of systolic/diastolic pulmonary venous flow velocity time integrals (0.8 +/- 0.4 to 1.4 +/- 0.5; p less than 0.001) were observed. An acute increase in mitral valve orifice area caused no significant changes in peak diastolic forward flow velocity (40 +/- 7 to 41 +/- 9 cm/s; p = not significant [NS]), diastolic forward flow velocity time integral (4.3 +/- 1.7 to 4.6 +/- 1.8 cm; p = NS) and atrial flow reversal velocity (30 +/- 3 to 35 +/- 3 cm/s; p = NS) compared with at baseline. The results suggest that in patients with severe mitral stenosis and sinus rhythm, left atrial filling is biphasic with a diastolic preponderance, and successful mitral valvuloplasty is associated with an immediate increase in pulmonary venous systolic forward flow.

Adult↗
PubMed1992

"Universal" T helper cell determinants enhance immunogenicity of a Plasmodium falciparum merozoite surface antigen peptide.

Synthetic peptide constructs containing a limited number of epitopes are being currently investigated as subunit vaccines against a variety of pathogens. However, because of widespread nonresponsiveness to most such constructs, possibly attributable to MHC restriction, the choice of appropriate carrier molecules to enhance immunogenicity of peptides constitutes an important and essential aspect of designing synthetic immunogens for human use. Widely used vaccines such as tetanus toxoid (TT) have not been uniformly effective as carrier proteins because of the phenomenon of epitope-specific suppression in which induction of an immune response against a synthetic peptide conjugated to TT is prevented by preexisting immunity to TT. Recently, T cell determinants that can be recognized in the context of several class II MHC molecules have been identified in tetanus toxin as well as in the circumsporozoite protein of a human malarial parasite, Plasmodium falciparum. Such determinants can be potentially used to circumvent the problem of epitope-specific suppression. In the present study we evaluated two such T cell determinants, viz., tt830-844 from tetanus toxin and CST3 from the malarial parasite, for their ability to help induce a boostable antibody response and to overcome genetic nonresponsiveness to a synthetic 20-residue construct containing a B cell and an overlapping T cell epitope from a major merozoite surface protein of P. falciparum. Our data provide support for the view that widely recognized T cell determinants may be used as universal carrier molecules for general vaccination.

Adolescent↗
PubMed1992

Breast metastases from malignant melanoma.

We review here 15 patients with cutaneous malignant melanomas metastatic to the breast. All but one were premenopausal females with a median age of 38 years. Most patients had a primary lesion on the upper extremities or trunk (80%), with only one patient having a lower extremity primary. The median interval between diagnosis of the primary and breast involvement was 33 months, with one patient developing breast involvement 11 years later, at the time of her second pregnancy. Five patients had bilateral breast involvement, and all had other sites of metastases at the time of diagnosis. The median survival after diagnosis of breast metastases was 10 months, portending a poor prognosis.

Adult↗
PubMed1992

Balloon angioplasty of native coarctation of the aorta in adolescents and young adults.

Balloon angioplasty of native coarctation of the aorta was performed in 35 consecutive adolescents and young adults, aged 14 to 37 years (mean 22.6 +/- 7.1). Twenty-eight (80%) patients had isolated discrete coarctation, six (17.1%) had tubular hypoplasia of the aortic isthmus, and one (2.9%) had hypoplasia of the post-coarctation aorta. The peak systolic pressure gradient decreased from 78.5 +/- 23.9 to 15.7 +/- 11.6 mm Hg (p less than 0.001), and the mean coarctation diameter increased from 4.7 +/- 2.4 to 13.1 +/- 2.7 mm (p less than 0.001) immediately after angioplasty. Patients with discrete-type coarctation had significantly less residual gradient than patients with long-segment tubular coarctation (12.3 +/- 10.7 vs 27.2 +/- 6.6 mm Hg, p less than 0.01). On recatheterization and angiography in 26 patients at 12.6 +/- 1.5 months after dilatation, there was no significant change in gradient (15.5 +/- 13.3 mm Hg) and diameter (13.1 +/- 1.8 mm) from the immediate post-angioplasty results. However, two patients had an increase in gradient and three had small aortic aneurysms with no change in appearance on restudy after 2 years. After 3 to 67 months' (mean 32.7 +/- 19.2) follow-up, all patients showed continued clinical improvement. Hypertension was relieved in 37.5% (12/32) and improved in 59.4% (19/32). Our experience suggests that balloon angioplasty of native aortic coarctation in adolescents and young adults is safe and highly effective with sustained improvement on intermediate-term follow-up.

Adolescent↗
PubMed1992

Balloon angioplasty of the aorta in Takayasu's arteritis: initial and long-term results.

Percutaneous transluminal balloon angioplasty for stenosis of the aorta was performed in 36 patients with Takayasu's arteritis (age range, 8 to 36 years; mean, 19.1 +/- 7.7 years). Balloon dilatation was successful in 34 patients and resulted in a decrease in the mean peak systolic pressure gradient (PSG) from 75.2 +/- 29.1 mm Hg to 24.8 +/- 19 mm Hg (p less than 0.001) and a mean increase in the diameter of the stenosed segments from 4.5 +/- 2.2 mm to 9.6 +/- 3.8 mm (p less than 0.001). Hemodynamic and angiographic restudy, which was performed in 20 patients at a mean follow-up period of 7.7 +/- 4.1 months (range, 3 to 24 months), showed a further decrease in PSG (greater than or equal to 15 mm Hg) in seven patients (from 40.0 +/- 11.2 mm Hg to 15.7 +/- 10.2 mm Hg; p less than 0.01), no significant change in PSG in 12 patients (17.1 +/- 13.6 mm Hg vs 16.6 +/- 12.7 mm Hg; p = NS), and an increase in PSG from 15 mm Hg to 85 mm Hg in one patient. The patient who showed restenosis underwent successful redilatation. Six patients who underwent late recatheterization and angiography at 36 to 60 months (mean, 43 +/- 9.4 months) show continued relief of stenosis (mean PSG, 8.8 +/- 7.8 mm Hg). Patients with short-segment (less than 4 cm) stenosis experience more relief than patients with long-segment (greater than or equal to 4 cm) stenosis (residual PSG, 18.6 +/- 8.2 mm Hg vs 40 +/- 16 mm Hg; p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Transoesophageal Doppler pulmonary venous flow pattern and left atrial spontaneous contrast in mitral stenosis.

The relationship between transoesophageal Doppler pulmonary venous flow pattern and spontaneous left atrial contrast was studied in 23 patients with isolated severe mitral stenosis (mitral valve area = 0.8 +/- 0.2 cm2). The patients with none or minimal (1+) spontaneous contrast (n = 15, group I) were compared with those with significant spontaneous contrast (grade 2+, n = 8, group II) with regard to peak systolic velocity (33 +/- 14 cm/s vs 28 +/- 12 cm/s, p = NS), peak diastolic velocity (36 +/- 14 cm/s vs 28 +/- 8 cm/s, p = NS) and peak atrial reversal velocity (19 +/- 4 cm/s vs 19 +/- 8 cm/s, p = NS), systolic forward flow velocity time integral (3.37 +/- 1.73 cm vs 2.78 +/- 0.9 cm, p = NS), diastolic forward flow velocity time integral (2.85 +/- 1.2 cm vs 2.65 +/- 1.87 cm, p = NS), ratios of peak systolic and diastolic velocity (0.91 +/- 0.21 vs 0.95 +/- 0.29, p = NS) and duration of diastolic deceleration (117 +/- 59 ms vs 132 +/- 106 ms, p = NS). The results show that the occurrence of spontaneous contrast in the left atrium in patients with mitral stenosis is not related to the Doppler-estimated pulmonary venous flow.

Adolescent↗
PubMed1992

Can mitral regurgitation after balloon dilatation of the mitral valve be predicted?

OBJECTIVE: To determine which factors predict the occurrence of mitral regurgitation after balloon dilatation of the mitral valve for rheumatic stenosis. DESIGN: Analysis of a case series of patients with rheumatic mitral valve stenosis who had had successful balloon dilatation of the mitral valve. SETTING: A tertiary care centre with an experience of over 150 balloon dilatations of the mitral valve. PATIENTS: 70 young patients with non-calcified rheumatic mitral stenosis, who had undergone successful balloon dilatation of the mitral valve. No patient had mitral regurgitation or atrial fibrillation before dilatation. INTERVENTION: Dilatation of the mitral valve by the transvenous, transatrial double balloon technique. MAIN OUTCOME MEASURE: Development of mitral regurgitation after balloon dilatation of the mitral valve and its relation to age, mitral valve area before dilatation and after dilatation, the degree of mitral subvalvar pathology, and the size of balloon used for dilatation. RESULTS: In 10 patients (14%) mitral regurgitation developed after balloon dilatation of the mitral valve. No statistically significant differences were found between patients who did not develop regurgitation and those who did in terms of age (mean (SD)) (19.9 (6.46) v 19.4 (5.5)), mitral valve area before dilatation (1.05 (0.33) v 0.94 (0.4) cm2) and after dilatation (2.52 (1.06) v 2.45 (1.1) cm2), mitral subvalvar pathology assessed by the mitral subvalvar distance ratio (0.116 (0.03) v 0.118 (2.32), or balloon diameter corrected for body surface area (21.37 (3.5) v 20.57 (2.32) mm/m2. CONCLUSIONS: In this subset of children and young adults with non-calcified mitral stenosis, none of the morphological, technical, or patient characteristics studied predicted the development of mitral regurgitation after balloon dilatation. The low incidence of mitral regurgitation may have reduced the discriminatory power of this study. None the less, the means and standard deviation for each factor in each group suggest that even in a larger sample size the variables would have little predictive capacity.

Adolescent↗
PubMed1992

Bypass of carrier-induced epitope-specific suppression using a T-helper epitope.

A gonadotropin-releasing hormone (GnRH)-based vaccine is being developed as a method for non-surgical immunotherapy as immunization with this vaccine results in atrophy of the prostate. This vaccine, a conjugate of GnRH and diphtheria toxoid (DT), provides a unique hapten-carrier system for investigating the influence of carrier presensitization on antibody responses to self haptens. In a recent communication we showed that preimmunization with carriers diphtheria toxoid and tetanus toxoid results in a strain-dependent inhibition of anti-GnRH responses in mice and that T cells from carrier-presensitized mice are responsible for anti-haptenic suppression. In the present report we describe a strategy for bypassing DT-induced epitopic suppression using a T-helper epitope from DT.

Animals↗
PubMed1992

Peribulbar anesthesia in retinal reattachment surgery.

We prospectively evaluated the effectiveness of peribulbar anesthesia in retinal reattachment surgery. Of the 24 patients studied, 2 required retrobulbar supplementation during the latter part of the surgery. Our results show that peribulbar anesthesia can be effectively used for retinal reattachment surgery and probably should be the preferred form of local anesthesia for this surgery, since the eyes involved have a relatively high incidence of axial myopia and posterior staphyloma.

Adult↗
PubMed1992

Echographic measurement of extraocular muscle thickness in proptosis.

Echographic extraocular muscle thickness was measured in 102 eyes of 51 patients with proptosis of varied etiology. That of vascular origin was associated with extraocular muscle enlargement in all cases. Enlargement of the medial rectus was found to be statistically significant in thyroid orbitopathy. Sixty percent of cases with nonspecific orbital inflammatory disease had enlarged extraocular muscles. We discuss the supportive role of determining echographic measurements of extraocular muscle thickness in proptosis and highlight the uniform extraocular muscle enlargement found in proptosis of vascular origin.

Adolescent↗
PubMed1992

The neurological aspects of acquired immune deficiency syndrome (AIDS)--a clinical review.

Ten years after it was diagnosed, AIDS is estimated to have affected 10 million people worldwide and about 2-3 million people in the United States. Initially considered to be a disease of coasts (New York, California, Florida), AIDS is making inroad to mid-America as well. It involves the nervous system in a variety of ways. These include direct involvement by the virus, secondary opportunistic infections, and tumors. The spectrum of nervous system involvement is the subject of our review.

AIDS Dementia Complex↗
PubMed1991

High-performance liquid chromatographic separation of bile acids and bile alcohols diastereoisomeric at C-25.

The high-performance liquid chromatographic separation of the 25R and 25S diastereoisomers of the bile alcohols 5 beta-cholestane-3 alpha,7 alpha,26-triol and 5 beta-cholestane-3 alpha,7 alpha, 12 alpha, 26-tetrol and the bile acids, 3 alpha,7 alpha-dihydroxy-5 beta-cholestane-26-oic acid and 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestane-26-oic acid is described. A Radial-Pak microBondapak C18 reversed-phase cartridge was used for the separations and elutions were carried out with acetonitrile-water-methanol-acetic acid mixtures. All eight diastereoisomeric compounds showed baseline separation when up to 200 micrograms of the isomeric mixtures were injected into the column and the method can be used for isolation of pure diastereoisomers of these bile acids and bile alcohols.

Alligators and Crocodiles↗
PubMed1991

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↗
PubMed1991

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↗
PubMed1991

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↗