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Biomedical subjects

R K Aggarwal

Publications and source records attributed to R K Aggarwal.

At least 55 records · Page 3Linked to original sources
PubMed1994

Early experience of directional coronary atherectomy: clinical results, complications and histopathological findings.

OBJECTIVE: To report the early experience, clinical results and histopathologic findings of Directional Coronary Atherectomy from a UK centre experienced in coronary angioplasty. DESIGN: Prospective study of the first 45 Directional Coronary Atherectomy (DCA) procedures using the Simpson coronary atherectomy device. RESULTS: Forty-five procedures were performed in 33 male and 5 female patients (mean age, 55.1 years). Directional Coronary Atherectomy was performed to 50 lesions (39 de novo, 11 restenosis; 44 left anterior descending, 3 right, 2 circumflex coronary arteries and 1 saphenous vein graft). Clinical and primary angiographic success was achieved in 43 of 45 cases (95.5%) and in 47 of 50 lesions (94%) after DCA alone. Before DCA the mean diameter stenosis was 88.7% (range, 50-100%) but following DCA (and percutaneous coronary angioplasty (PTCA) if necessary) the mean diameter stenosis was 3.5% (range, 0-15%; P < 0.001). Complications included occlusive dissection requiring coronary artery bypass surgery in two patients; abrupt closure of right coronary artery in one patient successfully reopened by PTCA and thrombolysis, complicated by excessive blood loss; reversible coronary artery spasm due to minor nose-cone trauma in four patients and temporary side branch loss in one patient. There were no coronary artery perforations, guide catheter complications, peripheral vascular trauma or deaths. On average 5.6 specimens (range, 1-18) were removed per case. Histology showed fibrous intimal plaque in 98%, media in 39% and adventitia in 7%. Neo-intimal hyperplasia was found in all restenosis lesions but also in 30% of de novo lesions. CONCLUSIONS: This small initial series indicates that directional coronary atherectomy is an effective and safe procedure for the treatment of obstructive coronary artery disease in carefully selected patients. With care, a high success rate can be achieved even during a learning phase. The technique is particularly effective for morphologically complex lesions that are unfavourable for PTCA. The procedure is unlike PTCA and requires additional training if pitfalls are to be avoided, high success rates achieved and complication rates kept low.

Adult↗
PubMed1994

Is measuring intraocular pressure necessary on the first post-operative day following uncomplicated cataract surgery?

A prospective study was undertaken to assess whether the level of intraocular pressure (IOP) on the first day after cataract surgery could be estimated by clinical examination only, thereby removing the need for applanation tonometry. A total of 70 patients underwent uncomplicated extracapsular cataract extraction and intraocular lens implantation. The following day a Consultant, Registrar and Senior House Officer were asked to identify those patients with significantly raised IOP (> 27 mmHg) using slit lamp examination only. A fourth examiner, masked to the assessments of the three observers, measured the IOP using the Goldmann applanation tonometer. Pressures of > 27 mmHg by Goldmann tonometry were found in 10 patients (14%) of which 8 (80%) were missed by all three ophthalmologists. Formal measurement of IOP appears a necessary part of the post-operative assessment after uncomplicated cataract surgery.

Aged↗
PubMed1993

Individualization and estimation of relatedness in crocodilians by DNA fingerprinting with a Bkm-derived probe.

Individual-specific DNA fingerprints of crocodilians were obtained by the use of Bkm-2(8) probe. Pedigree analyses of Crocodylus palustris, C. porosus and Caiman crocodilus revealed that the multiple bands (22-23 bands with Aludigest) thus obtained were inherited stably in a Mendelian fashion. Unique fingerprints permitted us to identify individuals, assign parentage, and reconstruct the DNA profile of a missing parent. Average band sharing between unrelated crocodiles was found to be 0.37. Band sharing between animals of known pedigrees increased predictably with relatedness and provided a basis for distinguishing relatives from non-relatives. Similar results obtained in other species/genera, using the same probe, suggest that this approach may be applicable to all species of crocodilians, and could facilitate genetic studies of wild and captive populations.

Alligators and Crocodiles↗
PubMed1993

Study on the stability of 17D-204 yellow fever vaccine before and after stabilization.

To monitor the parameters controlling yellow fever vaccine production, eight different lots produced without stabilizers were studied. It was found that the freeze-thaw cycle did not have any adverse effect on virus infectivity and the mean loss in virus titre during lyophilization was 0.51 log10 ml-1. A thermodegradation study after storage of vaccine at different temperatures showed that the vaccine did not pass the accelerated stability test. To stabilize the 17D-204 substrain vaccine, four stabilizers with different sugars and amino acids were examined. The optimum time for addition of the stabilizers was found to be during homogenization of infected embryos. An accelerated stability test at 37 degrees C indicated that stabilizers S1, S2 and S3 kept the vaccine stable for up to 4 weeks, whereas the vaccine was only stable for up to 3 weeks in stabilizer S4. Stabilizer S3 was found statistically to be the best. Reproducibility in production methodology was established by preparing and testing more batches of the vaccine using stabilizer S3.

Animals↗
PubMed1993

Extensive visual loss with topical facial steroids.

Steroid creams applied topically to the skin are routinely used in the treatment of many dermatoses. Their use on the face in severe atopic eczema is relatively common. We report a series of three patients who whilst using topical facial steroids developed advanced glaucoma. A further two cases of ocular hypertension secondary to topical facial steroids are also described. This is the first series of cases to be reported demonstrating the potentially blinding complications of topical facial steroids. Recommendations are made with regard to screening such patients for glaucoma.

Administration, Topical↗
PubMed1993

The role of nasolacrimal intubation in the management of childhood epiphora.

Nasolacrimal intubation has been advocated to obviate the need for dacryocystorhinostomy (DCR) for childhood epiphora which fails to resolve despite apparently successful probings. Twenty-eight intubations were attempted on children falling into this category. Of these, 25 were anatomically successful intubations (3 having had to be abandoned because of difficulties in retrieving the silicone tubes from the nose). Twenty patients (80%) had complete resolution of symptoms, 2 (8%) had improvement of symptoms such that no further intervention was necessary and 3 (12%) proceeded to DCR. A greater likelihood of a good outcome was seen if the tubes were left in situ for 6 months or more. We suggest that primary nasolacrimal intubation (that is nasolacrimal intubation without DCR) should be the next step in the management of childhood epiphora which fails to resolve after two probings. This approach may avoid a DCR in over 80% of children.

Child↗
PubMed1993

New materials for rectus muscle tendon extension in strabismus surgery.

Conventional strabismus surgery has both limitations and complications. Some of these have been overcome by the use of 'hang-back' sutures. Here we describe a new technique using Mersilene and Teflon as extraocular muscle implants for large muscle recessions. Results of initial studies in rabbits are presented and discussed. Mersilene implants evoked a marked fibroblastic reaction which limits their usefulness. Results with Teflon were more encouraging and suggest that it would be a useful spacer material in tendon extensions.

Animals↗
PubMed1992

Isolation of high-molecular-weight DNA from small samples of blood having nucleated erythrocytes, collected, transported, and stored at room temperature.

Blood samples collected in the field for isolating DNA suitable for molecular analysis need special care in their storage and handling. In this article, we describe a simple method for the isolation of good-quality high-molecular-weight DNA that does not require low temperature conditions during collection, storage, and/or transportation of blood samples. This method involves smearing small aliquots of blood onto clean slides and air drying them at room temperature. The slides with blood smears can then be transported or stored at room temperature and still serve as a very good source of high-molecular-weight DNA. Genomic DNA from these samples can be extracted by organic phase separation (phenol-chloroform extraction) after lysis. The DNA thus obtained is of high quality and yields DNA fingerprints qualitatively similar to those prepared from corresponding control DNA isolated from frozen blood samples. Needing minimal facilities at field sites, the method is very convenient for conducting RFLP analysis of wild/field populations for demographic, behavioral, and ecologic studies.

Alligators and Crocodiles↗
PubMed1992

Removal of scleral explant elements: a 10-year retrospective study.

There are several studies in the American literature on the incidence and causes of retinal redetachment following removal of explants. This is, to our knowledge, the first such study from Britain and differs in its findings from the American experience. The reason for removal of explants, the time of removal after initial detachment surgery and the consequences of removal were reviewed for the 10-year period from 1980 to 1990. During this period 1898 retinal detachment operations were performed at this centre, with an explant removal rate of 3.2% (61 eyes). Extrusion of the element was the cause in 74%. Of these 8% subsequently suffered a redetachment. In two eyes no retinal break was identified at initial surgery. Both of these suffered a redetachment following removal of the explant. Contrary to previous reports, redetachment was not related to short periods of explant or to infection of the explant. This study suggests that explant removal is a safe procedure. However, there is a significant risk of redetachment after explant removal if no breaks are identified at the time of initial surgery.

Adolescent↗
PubMed1992

Contrast sensitivity and glare in cataract using the Pelli-Robson chart.

There is a need for a convenient, clinically applicable test of glare disability which can be used in the preoperative evaluation of patients with cataract. In this study, contrast sensitivity (using the Pelli-Robson letter chart), near vision, and visual acuity were compared, with and without the introduction of a glare source in 70 patients with cataract, 15 with intraocular lenses, and 19 controls. A disposable pen torch was shone at the pupillary margin to induce glare. Contrast sensitivity demonstrated the most marked reduction during glare testing. Cortical cataracts were most affected followed by posterior subcapsular opacities. The glare disability was significantly less in pseudophakic patients and was absent from patients with non-cataractous phakic eyes. Glare testing with a disposable pen torch and a Pelli-Robson contrast sensitivity letter chart provides a rapid test of glare disability which can be easily incorporated into the clinical appraisal of patients with cataract.

Aged↗
PubMed1992

Relative performance of Organon kit in comparison to Du Pont for confirmatory serological testing of HIV infection by western blot test in sera from blood donors.

A total of 32 specimens with different categories of reactivity by Du Pont Western Blot kit comprising of specimens showing full spectrum of HIV-I antigen specific bands, 19 specimens showing total absence of bands and four specimens showing non-specific bands (without any interpretative importance) were subjected to Western Blot testing by Organon test. Of the nine specimens showing full spectrum of bands by Du Pont the correlation with Organon kit was 100 per cent based on WHO criteria. Four specimens with non-specific indeterminate band pattern by Du Pont failed to show any band in Organon kit, indicating that latter to be more specific.

AIDS Serodiagnosis↗
PubMed1991

The quantitation of rabies-specific antibodies. I. Modified counter immunoelectrophoresis. A rapid and sensitive method.

Modified counter immunoelectrophoresis was standardized with respect to dilution of tissue culture antigen and indicator serum, the incubation time for neutralization and the effect of an electric current. The technique was found to be sensitive enough to detect a minimum level of antibodies (0.5 IU/ml) by using a 16 mA current per slide for 2 h, indicator serum of 15 IU/ml and the use of an antigen at a concentration of 1:35. Above all, the incubation period did not affect the neutralization of the virus. The test was also applied to the detection of rabies-specific antibody levels in 73 human sera. The test was found to be simple, quick and economical for titration of rabies antibodies.

Antibodies, Viral↗
PubMed1991

The quantitation of rabies-specific antibodies. II. Factors affecting the sensitivity of the haemagglutination inhibition test.

Various factors affecting the HAI test for the quantitation of rabies-specific antibodies have been evaluated with a view to obtaining maximum sensitivity and reproducibility in tests using tissue culture antigens prepared in vero cells and concentrated by dialysis. Goose erythrocytes treated with proteolytic enzyme bromelian at a concentration of 0.025% were much more susceptible to HA than those that were untreated or erythrocytes treated with neuraminidase. In addition, other parameters like the use of a phosphate buffered saline (PBS) as a diluent at pH 6.2, incubation at 0-4 degrees C for 1.5-3 h were found to be most critical for achieving maximum HA activity. To remove non-specific inhibitors, serum samples were treated with aerosil, acetone in combination or alone. Of the 73 serum samples tested, removal of non-specific inhibitors by aerosil alone occurred in up to 54.79% of the samples, whereas using acetone-aerosil treatment followed by adsorption with goose erythrocytes, the inhibitors were removed in 98.67% of the samples to a level that was undetectable at the 1:4 starting dilution in the HAI test.

Acetone↗
PubMed1991

The quantitation of rabies-specific antibodies. III. A comparative evaluation of modified counter immunoelectrophoresis, haemagglutination inhibition and serum neutralization titres of human sera.

The rabies-specific antibodies of 73 serum samples from vaccinated humans were determined by the modified counter immunoelectrophoresis (MCIE), and the haemagglutination inhibition test (HAI) by using the conventional serum neutralization test (SN) as a yard-stick. Both MCIE and HAI were found to be sensitive and specific for the estimation of rabies antibodies. In general, the unitages obtained by the MCIE and SN showed statistically insignificant differences (P greater than 0.05) and the correlation coefficient between the two methods was 0.697 (P less than 0.05). Although the unitage of the sera detected by HAI tests was lower by a factor of 0.155 from the unitage of SN tests, there was statistically insignificant differences between the two techniques (P greater than 0.05) with a correlation coefficient of 0.556 (P less than 0.05).

Antibodies, Viral↗