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Biomedical subjects

S M Shah

Publications and source records attributed to S M Shah.

At least 55 records · Page 3Linked to original sources
PubMed1995

Retinal detachment in AIDS-related cytomegalovirus retinitis.

Patients with acquired immune deficiency syndrome (AIDS) and cytomegalovirus retinitis (CMVR) are surviving longer due to the use of virostatic medicines and improved treatment of opportunistic infections. As a result, retinal detachment is likely to become an increasingly common cause of visual morbidity in these patients. The incidence and outcome of retinal detachment complicating CMVR was studied at two London AIDS centres. Patients with CMVR were identified prospectively and underwent standard treatment. Retinal detachments were diagnosed during regular follow-up. If retinal reattachment surgery was performed, a standard procedure of vitrectomy and silicone oil internal tamponade was employed. Of 147 patients with CMVR, 41 (28%) developed retinal detachments (47 eyes). Forty-three detachments were rhegmatogenous and 4 were exudative. Fifteen eyes of 9 patients with rhegmatogenous detachments underwent retinal reattachment surgery. Of these, visual acuity remained stable or improved in 12 eyes (80%) in the immediate post-operative period. At the last clinic visit, 8 eyes (53%) maintained a visual acuity of 6/60 or better. The visual results of surgery are good in selected patients, bearing in mind the progressive nature of the underlying disease and poor life expectancy.

AIDS-Related Opportunistic Infections↗
PubMed1995

HIV-1 prevention: interdisciplinary studies on the efficacy of bleach and development of prevention protocols.

In the United States, a major federally-funded approach to HIV-1 prevention for injecting drug users (IDUs) includes teaching them to always rinse their needles/syringes with household bleach and water before use. This report describes interdisciplinary studies of the extent to which HIV-1 can be found in injection equipment and the efficacy of bleach as a disinfectant, under simulated field conditions. Bloody needle/syringe units collected from Miami, Florida, shooting galleries or from community outreach prevention participants were selected for these studies. Groups of needle/syringe units were cleansed with bleach using a standard technique taught to IDUs in community outreach programs. Cleansed and uncleansed groups of needles/syringe units were then tested for the presence of HIV-1. The data demonstrate the efficacy of bleach rinses in reducing the risks of HIV-1 infection from needle/syringe units and indicate that the teaching of a bleach cleansing method to IDUs should be part of a total AIDS prevention protocol.

Disinfection↗
PubMed1994

Changes in anterior chamber flare and cells following cataract surgery.

The laser flare cell meter allows rapid non-invasive quantification of aqueous flare and cells. In this prospective study laser photometry was used to document the recovery of the blood-aqueous barrier in 27 normal eyes following cataract surgery. Aqueous flare and cells were highest on the first postoperative day, declining rapidly in the first week and returning to preoperative levels by 3 months. In six eyes (22.2%) there was an increase in either flare and cells or flare alone during the first postoperative week which was associated with a delayed recovery of the blood-aqueous barrier for up to 1 month following surgery. A consensual flare response was found to occur in the fellow eye in five patients (18.5%).

Aged↗
PubMed1994

Preliminary laboratory studies of inactivation of HIV-1 in needles and syringes containing infected blood using undiluted household bleach.

To evaluate the effectiveness of bleach disinfection of injection equipment, we tested HIV-1 inactivation by household bleach in needles and syringes. We obtained blood from HIV-1 infected injecting drug users (IDUs), placed small aliquots in needles and syringes. Blood with and without anticoagulant was incubated at room temperature for 3, 6, 18, and 24 h, and some needles and syringes from each condition were exposed to undiluted bleach for 15 and 30 s. The needles and syringes were then rinsed and the rinses were used to inoculate peripheral blood mononuclear cells (PBMNCs). HIV-1 replication was monitored using p24 enzyme linked immunosorbent assay (ELISA). We describe results that HIV-1 is inactivated in clotted and unclotted blood allowed to stand at room temperature for 3, 6, 18, and 24 h in needles and syringes using undiluted household bleach at 30 s of exposure time. These results are consistent with earlier findings that micropellets of HIV-1 were inactivated by bleach under similar conditions of exposure to bleach; 10% bleach was not effective at an exposure time of 30 s and undiluted bleach was not effective at an exposure time of 15 s to inactivate HIV-1 in clotted blood. Bleach concentration and exposure time are critical and HIV disinfection may not occur with inadequate exposure to bleach HIV.

Disinfection↗
PubMed1993

Comparison of the anterior chamber inflammatory response to diode and argon laser trabeculoplasty using a laser flare meter.

BACKGROUND: Diode laser trabeculoplasty (DLT) has a similar hypotensive action to argon laser trabeculoplasty (ALT). However, anterior chamber inflammatory response and laser-induced discomfort are less pronounced with DLT. The authors compared the breakdown of the blood-aqueous barrier after DLT and ALT over the time course of 1 week and the hypotensive action over 8 weeks. METHODS: Twenty-five patients with uncontrolled intraocular pressure (IOP) were randomized to either DLT or ALT. If two eyes required treatment, then the second eye would be treated with the alternative laser to the first. Flare values were measured at 1, 3, 24, 48, 72, 96, and 168 hours using a laser flare and cell meter. Intraocular pressures were measured at similar intervals and at 8 weeks. RESULTS: Of 38 eyes treated, 21 underwent ALT and 17 DLT. Both forms of treatment induced a similar hypotensive effect with a significant reduction in IOP at 8 weeks compared with initial IOP (P < 0.01) (paired Student's t test). However, there was a significantly greater disruption of the blood-aqueous barrier with ALT when compared with DLT at 1, 3, and 24 hours (P < 0.001) and at 48, 72, and 96 hours (P < 0.01) (unpaired Student's t test). By 1 week, however, there was no significant difference in flare values between the two groups. Postlaser pain occurred in seven eyes treated with ALT but in no eyes treated with DLT. In addition, peripheral anterior synechiae occurred in four eyes after ALT by 8 weeks but none occurred in the DLT group. CONCLUSION: Argon laser trabeculoplasty produces a greater disruption of the blood-aqueous barrier than DLT. This may be associated with the development of complications in the anterior segment.

Aged↗
PubMed1993

Specular microscopy of the anterior intraocular lens surface.

Until recently the cytological assessment of the intraocular lens (IOL) surface was only possible using in vitro cytopathological techniques on explanted lenses or in animal models. Specular microscopy provides an in vivo method for the observation of the IOL surface at high magnification. We have used this technique to examine the IOL surface of 27 normal pseudophakic eyes in the first 3 months following implantation. Cellular deposits consisting of small and giant inflammatory cells were found to be a normal occurrence in otherwise clinically successful cataract surgery. It was also possible to visualise the anterior capsule and its attachment to the IOL surface, an amorphous surface membrane, pigment, surface contaminants (starch granules and fibres), and the markings caused by instrumentation at the time of implantation. The technique of IOL surface specular microscopy therefore provides a useful method for the visualisation of the IOL surface and the cytological reaction that occurs there, and thus allows an assessment of IOL biocompatibility.

Aged↗
PubMed1993

A comparison of the laser flare cell meter and fluorophotometry in assessment of the blood-aqueous barrier.

PURPOSE: To evaluate and compare the use of the Kowa laser flare cell meter and intravenous anterior chamber fluorophotometry in assessment of the blood-aqueous barrier after cataract surgery. METHOD: Laser flare and cell measurements and fluorophotometry were performed at 1 and 3 months after surgery in 48 eyes of 44 patients admitted for routine cataract surgery. The fellow pseudophakic eyes of these patients were used as controls. RESULTS: The two techniques measure different parameters, but both methods are able to document the integrity or breakdown of the blood-aqueous barrier. However, the laser flare cell meter is more sensitive in quantifying subtle changes in barrier function to large molecules (proteins). Various methods of assessing anterior chamber fluorophotometry data were also compared. Measurement of a diffusion coefficient (requiring the measurement of plasma fluorescence) was not found to be more sensitive than other methods and did not alter the clinical significance of data obtained from the measurement of anterior chamber fluorescence alone. CONCLUSIONS: Both the laser flare cell meter and fluorophotometry provide a method for the assessment of the postoperative blood-aqueous barrier. However, the laser flare cell meter is rapid, noninvasive, and relatively easier to use. Therefore, for clinical use, it has great practical advantages over fluorophotometry.

Adult↗
PubMed1992

HIV-1 in postmortem brain tissue from patients with AIDS: a comparison of different detection techniques.

OBJECTIVE: The presence of HIV-1 in postmortem brain tissue from 31 patients with AIDS and 12 HIV-1-negative controls was investigated. DESIGN: Most laboratories have access to the methods used. We readily applied in situ hybridization and immunohistochemistry to archival formalin-fixed paraffin-embedded (FFPE) brain specimens. METHODS: The techniques used to detect HIV-1 were explant culture, in situ hybridization with 35S-labeled polymerase (pol) gene riboprobes and immunohistochemistry with monoclonal antibody to gp41. RESULTS: HIV-1 was isolated from explant cultures in 13 out of 20 (65%) patients, whereas HIV-1-infected cells were detected in FFPE brain tissue from nine out of 26 (35%) patients examined by in situ hybridization and in seven out of 26 (27%) patients examined by immunohistochemistry. CONCLUSIONS: Although the isolation technique was the most sensitive of the three techniques tested, infected cells may be identified with in situ hybridization in conjunction with immunohistochemistry.

AIDS-Related Opportunistic Infections↗
PubMed1992

The effects of subconjunctival betamethasone on the blood aqueous barrier following cataract surgery: a double-blind randomised prospective study.

The aim of this double-blind randomised prospective study was to assess the effect of subconjunctival Betnesol (betamethasone sodium phosphate 0.1%) on the recovery of the blood aqueous barrier (BAB) following cataract surgery in uncomplicated eyes. Twenty patients [10 male, mean age 71.4 (SD 12.7) years] admitted for routine cataract surgery were randomised into two groups. All patients recruited into the study were free of other ocular disease and were not taking any anti-inflammatory medication. Group A received a subconjunctival injection of cefuroxime (125 mg) alone while group B received a subconjunctival injection of both cefuroxime and Betnesol. All surgery was performed by a single surgeon using a standardised surgical technique and all patients received the same postoperative medication. The Kowa laser flare cell meter was used to measure aqueous flare and cells preoperatively and on the first, second, and seventh postoperative day, and at 1 and 3 months following surgery. The code was broken only after all patients had been followed-up for 3 months postoperatively. There was no significant difference between the two groups in aqueous flare and cells at any of the postoperative visits. In this study we were unable to demonstrate any beneficial effect of subconjunctival betamethasone on damage to and recovery of the BAB following cataract surgery in the uncomplicated eye.

Adult↗
PubMed1992

Correlations between laser flare measurements and anterior chamber protein concentrations.

The laser flare cell meter quantifies anterior chamber (AC) protein (flare) by measuring light scattering of a helium-neon laser beam in the AC. The relationship between photon count and protein concentration both in vitro and in vivo was assessed. The reproducibility of the in vitro photon count measurements was 7.3%. There was a significant linear relationship between photon count and the concentration of both albumin (r = 1.0, P = 0.0001) and immunoglobulin G (IgG, r = 0.99, P = 0.0001) in vitro, but the linear-regression formulas were different with greater light scattering by IgG than by albumin at the same concentration. Laser flare measurements were done on 22 patients (12 normal eyes, 5 eyes with Fuchs' heterochromic cyclitis, and 5 uveitic eyes) before cataract surgery. Aqueous humor obtained from these patients by paracentesis was analyzed for total protein, albumin, and IgG concentration. There was a significant linear relationship (r = 0.88, P = 0.0001) between the laser flare value (range, 5.8-107.8 photons/msec) and the total aqueous protein concentration (range, 14-388 mg/dl). Use of an in vitro albumin calibration curve to convert photon count into protein concentration was found to overestimate the actual protein concentration. This overestimation was slight in normal eyes and increased with increased blood-aqueous barrier breakdown. The use of such a calibration curve therefore is not appropriate in studies on diseased eyes. The authors recommended that laser flare results be expressed in either photons per milliseconds or converted into an equivalent protein concentration using a calibration curve based on actual AC protein measurements.

Aged↗
PubMed1992

Carcinoma in an oesophageal diverticulum.

A young male who had minimal dysphagia since childhood complained of increasing difficulty in swallowing for a few months. Upper Gastrointestinal endoscopy was normal on two occasions done by two gastroenterologists. Barium swallow showed minimal extrinsic pressure on the oesophageal wall. X-ray chest was normal. CT scan showed a large growth close to the oesophagus. Resection of the growth showed a carcinoma completely filling an oesophageal diverticulum with a normal oesophageal lumen.

Adult↗
PubMed1991

Measurement of aqueous cells and flare in normal eyes.

(abstractThe Kowa laser cell flare meter has been recently introduced to quantify the assessment of aqueous cells and flare in vivo by measurement of light scattering from a low power HeNe beam. Computer analysis of this scattered light can distinguish cells (expressed as cell count) from protein (expressed as photon count/ms), and in-vitro work with albumin solutions has shown that the photon count/ms is linearly related to protein concentration. This study of 106 normal eyes (53 subjects) assesses the accuracy and sensitivity of the instrument and the factors affecting the interpretation of its results. Using in-vitro solutions of human albumin we found a highly significant linear correlation (r = 1, p = 0.0001) between photon count and protein concentration. The results show that the instrument has a photon count/ms reproducibility of 8.26% and that there is a within-subject variability in photon count/ms (aqueous flare) of 12.2% in normal eyes. No significant difference in photon count/ms (aqueous flare) was found to exist between right and left eyes (p greater than 0.4), between sexes (p greater than 0.5), or between irides of different colour (p greater than 0.8). There was also no statistically significant variation in photon counts/ms with time of day over the period of measurement (1000-1900 h) (p = 0.4). There was, however, an increase in photon count/ms with age (r = 0.57, p less than 0.001) and a decrease with pupillary dilatation at both 30 and 60 minutes after instillation of tropicamide 1% (p less than 0.05). An occasional cell was found in only 10.4% of normal eyes, and there was no significant increase in the cell counts on mydriasis (p>0.05). These findings indicate that the Kowa laser flare meter is an accurate and sensitive instrument with potential application in the investigation of blood-aqueous barrier.

Adolescent↗
PubMed1990

New Sivapithecus humeri from Pakistan and the relationship of Sivapithecus and Pongo.

New humeri of two species of the Miocene hominoid Sivapithecus are described from near Chinji in Pakistan from between approximately 9 and 11 Myr ago. Sivapithecus, a middle and late Miocene hominoid from Turkey and Indo-Pakistan, is overall unlike any living hominoid, although facial-palatal similarities to the extant orangoutan, Pongo, have been used to support a hypothesis of close relationship. Living hominoids have postcranial similarities assumed to be shared derived, among them features of the proximal humerus. However, the new Sivapithecus proximal humeri differ from those of living hominoids, supporting an alternative hypothesis in which Sivapithecus and Pongo are not closely related. It is not clear how to choose between these incompatible hypotheses.

Animals↗
PubMed1990

Isolation of Helicobacter pylori from dental plaques in healthy volunteers.

The presence of Helicobacter pylori (H pylori) was looked for in dental plaques of 40 healthy volunteers by CLO test, culture and smear stained with Warthin-Starry stain. H pylori was found to be present in the dental plaques of all 40 volunteers. The dental plaque is an important reservoir of H pylori.

Adolescent↗
PubMed1990

Human immunodeficiency virus cultured from bone. Implications for transplantation.

This study demonstrates by a virologic culture method that human immunodeficiency virus (HIV) resides in bone. After freezing, some initially positive specimens no longer yielded virus, but those that continued to yield virus were not further altered by subsequent washing, which removed essentially all marrow, or by freeze-drying. The safeguards against potential transmission of HIV by a bone allograft are principally the screening and testing methods previously described, although there may be a further reduction of the remote residual risk by the freezing step in the usual technical sequence for tissue banking by sterile techniques.

Acquired Immunodeficiency Syndrome↗