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Biomedical subjects

K A Shah

Publications and source records attributed to K A Shah.

At least 19 recordsLinked to original sources
PubMed2004

Effects of clinical service reorganisation on cellular pathology workload.

AIMS: To assess changes in volume and complexity of cellular pathology workload after clinical service reorganisation and alterations in pathology reporting practices, and to identify objective measures of change applicable to all cellular pathology departments. The ear, nose, and throat (ENT), head and neck (HN) specialty was chosen for assessment. METHODS: Cellular pathology workload from the ENT-HN surgical specialty was assessed numerically and the complexity in examination of cancer resection specimens was evaluated. Medical and technical time inputs in the reporting of ENT-HN cancer resections were measured prospectively, and the histological and cytological workload arising from the management of such cases was obtained. RESULTS: The 88.83% increase in ENT-HN specimens contrasted with a 13.53% increase in total surgical workload. Substantial increases in work complexity were found when measured as blocks/slides for each case and number of histochemical/immunohistochemical requests. On average, examination of one ENT-HN cancer case consumed 55% of one pathologist's work session and over one 10th of a technician's working week. On average, each cancer generated 3.3 histological and 1.06 cytological specimens. CONCLUSIONS: Evidence is provided of the increase in cellular pathology workload and in its complexity. This study lists objective measures of complexity applicable to all pathology subspecialties. Given the workforce crisis and expanding clinical needs, realistic workload calculations should include measurement of complexity and not just volumes.

England↗
PubMed2003

Myxoglobulosis in oral extravasation mucocele: an entity?

AIMS: Myxoglobulosis is a recognized variant of mucocele of the vermiform appendix. Myxoglobulosis has recently been reported in extravasation mucocele of the oral cavity. This morphological study was carried out to identify the prevalence and possible pathogenesis of this unusual feature. MATERIALS AND METHODS: A retrospective review of archival material diagnosed as oral cavity mucocele was undertaken. This covered a period of 32 months and consisted of 76 cases. In accordance with the proposed traumatic origin of extravasation mucocele, histological changes were classified on the basis of mucin extravasation and cyst formation. Globular structures, as described in the reports of myxoglobulosis, were looked for, as were changes that could be ascribed to their formation. CONCLUSIONS: Globular structures were noted in 22 (31%) of 71 cases of extravasation mucocele. They were present within cysts (11 samples) and in extraluminal connective tissue in the rest. They appeared to originate from alterations in connective tissue collagen following mucin extravasation. Their structure is different from that described in appendicial mucocele. When observed, they are best regarded as part of the normal sequence in the formation of oral cavity extravasation mucocele, without attaching special importance to them.

Humans↗
PubMed1998

Effects of peroxide on endothelial nitric oxide synthase in coronary arteries.

Reactive oxygen species (ROS) are produced in ischemia and reperfusion. Since endothelial nitric oxide synthase (eNOS) is key to the endothelium-dependent vasodilation, we examined the effects of peroxide on this enzyme. We treated cells cultured from pig coronary artery endothelium with different concentrations of hydrogen peroxide, washed them, solubilized them and measured NOS activity by arginine to citrulline conversion. Hydrogen peroxide inhibited the eNOS activity with an IC50 value of 0.85 +/- 0.39 mM. In another experiment, we perfused arteries with solutions containing 0 or 1 mM hydrogen peroxide, washed them, removed the endothelium using a cotton swab, centrifuged and solubilized the endothelium and monitored its NOS activity. Hydrogen peroxide (1 mM) did not affect the NOS activity significantly (p > 0.05) in this assay. We conclude that the inactivation of eNOS by hydrogen peroxide does not play a major role in the ischemia-reperfusion damage because the peroxide concentrations attained during ischemia-perfusion are much lower than those affecting the eNOS activity.

Animals↗
PubMed1997

Apoptosis after intestinal ischemia-reperfusion injury: a morphological study.

BACKGROUND: Apoptosis has been identified after ischemia-reperfusion (IR) injury to the brain, heart, kidney, retina, and the adrenals. Intestinal IR injury causes villous and crypt damage, which has so far been attributed to cellular necrosis. This study was undertaken to investigate the possible role of apoptosis after reperfusion of cold-stored small bowel grafts in syngeneic rats. METHODS: Small intestinal grafts were stored at 4 degrees C for 24 hr in saline (n=6) or in modified University of Wisconsin solution (n=6), followed by reperfusion for 1 hr in syngeneic Lewis rats. Small bowel samples were obtained before storage, after preservation and after 1 hr of reperfusion. They were processed for light and electron microscopy and analyzed for cell death, with particular emphasis on apoptosis. RESULTS: Less than one apoptotic event was seen per 10 crypts in normal and stored bowels. An occasional normal and some denuded villous epithelial cells of stored bowels exhibited apoptosis. After isotransplantation and 1 hr of reperfusion, marked increase in apoptosis was seen in the crypts and denuded villous epithelial cells of both saline- and modified University of Wisconsin-stored bowels. Secondary necrosis was seen in apoptotic cells, as were dark cells. Only a few cells showed signs of primary ischemic necrosis. CONCLUSIONS: Apoptosis occurs after intestinal IR injury. Modulation of its genetic regulatory and biochemical effector machinery might alleviate or even prevent IR injury in small bowel transplanted after similar periods of storage.

Animals↗
PubMed1997

Intestinal metaplasia subtyping: evaluation of Gomori's aldehyde fuchsin for routine diagnostic use.

AIMS: Intestinal metaplasia (IM) has been implicated in the pathogenesis of gastro-oesophageal carcinoma, but because of its common occurrence, its specificity for use in cancer surveillance is low. IM subtypes characterized by mucin phenotype have been studied to try and improve specificity. METHODS AND RESULTS: On balance, type III IM seems the most promising for use in gastric cancer surveillance. The situation is problematic at the gastro-oesophageal junction where the normal occurrence of acidic mucins raises doubt on the value of subtyping. High iron diamine-Alcian blue combination (HID-AB) is commonly used for IM subtyping, but its potential toxicity and long staining period (up to 24 hours) precludes widespread clinical use. This study has compared the sulphomucin staining ability of Gomori's aldehyde fuchsin-Alcian blue combination (GAF-AB) against HID-AB for identifying and subtyping IM in gastric and oesophageal biopsies. CONCLUSIONS: Compared to HID-AB, a sensitivity of 85%, a specificity of 100% and a staining time of less than 30 minutes, shows this stain to be a simple and effective technique for identifying and subtyping IM in routine laboratories.

Biopsy↗
PubMed1997

Characterization of apoptosis in intestinal ischaemia-reperfusion injury--a light and electron microscopic study.

Intestinal ischaemia-reperfusion (IR) injury has largely been attributed to cellular necrosis. Apoptosis, a distinct form of cell death has been observed following IR to the brain, heart, adrenals and the kidneys. In order to characterize the role of apoptosis in intestinal IR, small bowel grafts were stored in saline (n = 6) or modified University of Wisconsin solution (n = 6) at 4 degrees C for 12 h and reperfused for 6 h in syngeneic rats. Samples of normal, stored and reperfused intestines at 1, 3 and 6 h were analysed by light and electron microscopy. Following reperfusion, there was crypt and villous epithelial apoptosis, loss of crypt and villous structures, and an increase in mucosal inflammatory cell infiltration. Ongoing apoptosis was maximum at 1 h, its degree decreasing with increasing reperfusion intervals. Large numbers of apoptotic bodies dominated the picture from 3 h of reperfusion. This study has demonstrated the induction of apoptosis by intestinal IR injury, which begins within an hour of reperfusion and is probably responsible for the observed crypt and villous loss. This has potential therapeutic implications as, opposed to necrosis, apoptosis is an active process with genetic regulators and biochemical effectors, which can be specifically targeted to prevent or alleviate IR injury.

Adenosine↗
PubMed1996

A precursor of the nitric oxide donor SIN-1 modulates the stress protein heme oxygenase-1 in rat liver.

In this study the effect of increased nitric oxide (NO) production on the expression of rat liver heme oxygenase-1, an inducible stress protein responsible for the catalysis of heme to biliverdin and carbon monoxide, was investigated. Rats were injected intraperitoneally with molsidomine (SIN-10), a long acting drug that is enzymatically converted in the liver to yield the active NO-releasing agent 3-morpholinosydnonimine (SIN-1). Administration of SIN-10 resulted in a significant time- and dose-dependent increase in plasma levels of nitrite/nitrate, an index of NO release. A time course of heme oxygenase-1 mRNA levels in liver showed a gradual increase in the expression of the gene encoding for this protein, which was maximal at 4 hours and returned to normal levels by 6 hours after SIN-10 treatment. Heme oxygenase activity also increased by 50% at 4 hours and was maximal 12 hours after SIN-10 administration (63% increase over baseline). These results indicate a possible role for locally generated NO in the modulation of hepatic stress response in vivo suggesting that NO mediates cell adaptation to stress by activation of endogenous defensive mechanisms.

Animals↗
PubMed1996

Cold ischemia-induced damage to vascular endothelium results in permeability alterations in transplanted lungs.

UNLABELLED: Despite suggestions of a connection between endothelial damage and permeability alterations after ischemia and reperfusion in pulmonary tissue undergoing transplantation, no direct correlation between vascular endothelial discontinuity and parenchymal edema has yet been shown. METHODS: Forty-two rat lungs were harvested and stored for 48 or 72 hours under hypothermic and ischemic conditions. Stored pulmonary tissue was studied before transplantation and 5 minutes or 24 hours after transplantation by light microscopy and scanning electron microscopy of arterial vascular endothelium. RESULTS: Stored lungs not subjected to revascularization showed moderate perivascular edema, with small intercellular gaps in endothelial monolayers. Five minutes after transplantation, pulmonary tissue appeared congested, with perivascular and alveolar edema. Examination of vascular endothelium by scanning electron microscopy showed detachment of endothelial cells. Twenty-four hours after transplantation, edema, hemorrhage, and vascular congestion were found in all specimens. Arterial vascular endothelium showed weak intercellular connections, numerous intercellular gaps, and widespread cell detachment. Bronchial epithelial cells appeared damaged after storage, with loss of cilia, blebbing of apical cytoplasm, and cellular rounding. These changes were maintained 5 minutes after transplantation but appeared totally reversed after 24 hours in specimens stored 48 hours, whereas bronchial denudation was observed in 72-hour stored lungs. Statistically significant positive correlations (Kendall p < 0.001) between revascularization time and alveolar edema and hemorrhage were found for both storage periods. CONCLUSION: The results from this study demonstrate correlation between loss of endothelial monolayer continuity and histologic evidence of vascular permeability increases in pulmonary tissue before and after lung transplantation.

Adenosine↗
PubMed1992

High-performance liquid chromatographic analysis of docusate sodium in soft gelatin capsules.

A rapid and simple high-performance liquid chromatographic (HPLC) method for the analysis of docusate sodium in soft gelatin capsules was developed with progesterone as the internal standard. The method requires a reversed-phase column and a paired-ion technique to separate docusate sodium from other components. A C22 column was used with a mobile phase of acetonitrile:water (70:30) containing 0.005 M tetrabutylammonium phosphate. The flow rate was 1.8 mL/min, and the effluent was monitored at 214 nm. Docusate sodium and progesterone had retention times of 4.5 and 6.8 min, respectively. The proposed HPLC method is linear, accurate, and precise. A mean assay value of 99.6% was obtained by the proposed method when five samples, each containing a composite of 10 capsules, were analyzed. The results obtained by the proposed HPLC, tetra-n-butylammonium iodide titration, and USP XXII HPLC methods are compared.

Calibration↗
PubMed1984

Liquid chromatographic analysis of dichlorophen and its major impurity.

A rapid and simple high-performance liquid chromatographic (HPLC) method for the analysis of dichlorophen in raw material and in dichlorophen-toluene soft gelatin capsules for veterinary use was developed using a reverse-phase technique. This HPLC system was shown to isolate dichlorophen from its major impurity (the trimer). Three formulations were assayed and were found to contain 7.14, 7.90, and 8.4% of the trimer. A C-18 column was used with a mobile phase of methanol-water (75:25). The flow rate was 1.5 mL/min, and the effluent was monitored at 290 nm for both dichlorophen and the trimer. Dichlorophen and the trimer had retention times of 6.5 and 9.0 min, respectively.

Capsules↗
PubMed1980

Effect of pH, chlorobutanol, cysteine hydrochloride, ethylenediaminetetraacetic acid, propylene glycol, sodium metabisulfite, and sodium sulfite on furosemide stability in aqueous solutions.

A study was conducted to determine the effects of pH, two antioxidants, a chelating agent, a preservative, and propylene glycol on furosemide stability. Aqueous solutions of furosemide containing 10% alcohol (v/v) were prepared in phosphate buffers with various pH values (5, 6, and 9) whose ionic strength was adjusted to 0.1 M with potassium chloride. Some solutions contained chlorobutanol, ethylenediaminetetraacetic acid, or sodium metabisulfite. Another set of aqueous solutions contained phosphate buffer (0.1 M), alcohol (10% v/v), and propylene glycol (40% v/v) with or without cysteine hydrochloride, ethylenediaminetetraacetic acid, and sodium sulfite. The solutions were divided into two parts, stored at 24 and 50 degrees, and assayed frequently using a previously developed high-pressure liquid chromatographic procedure. At the lowest pH value (pH 5), furosemide appeared to be very unstable. Cysteine hydrochloride, ethylenediaminetetraacetic acid, and sodium sulfite failed to improve the stability of furosemide. Chlorobutanol and sodium metabisulfite had an adverse effect on the stability, probably due to the fact that they decreased the pH of the solution. The pH value appears to be the only critical factor for the stability of furosemide. Buffered solutions containing propylene glycol were very stable at both temperatures for 170 days, and they tasted good.

Chemical Phenomena↗