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Biomedical subjects

N Shaikh

Publications and source records attributed to N Shaikh.

At least 19 recordsLinked to original sources
PubMed2003

Small joint fusion of the hand--a technique using Coughlin cup and cone reamers.

We describe a method of cup and cone arthrodesis using Coughlin concave and convex reamers, which we have used in a series of 22 hand joints in 19 patients. These reamers, originally designed for use in the foot, can be used in the hand to give very accurate preparation of bone surfaces. This results in maximum bone contact and the ability to fuse the joint in any desired position. The procedure is simple, rapid and forgiving. Union was achieved in all 22 cases, usually within 3 months.

Adult↗
PubMed2001

Detection of recurrent breast cancer after TRAM flap reconstruction.

Breast cancer remains a significant cause of morbidity and mortality among women today. The transverse rectus abdominis myocutaneous (TRAM) flap has played a substantial role in the reconstruction of defects secondary to mastectomy. Although such reconstruction has not been shown to adversely affect survival or local recurrence, specific screening modalities for recurrence in this population of patients have not been delineated. Three patients were examined retrospectively at the authors' institution. They presented with local recurrences of breast cancer after mastectomy and TRAM flap reconstruction. All patients' recurrences were detected on physical examination, and all had the diagnosis of recurrent carcinoma made on biopsy of the mass. A review of the literature demonstrates that mammography, ultrasound, magnetic resonance imaging (MRI), computed tomography (CT), scintimammography, and biopsy have all been used as adjuncts to clinical examination in detecting recurrence. Subsequent treatment of recurrent breast cancer is determined by the results of a metastatic workup and the receptor status of the tumor. The most reliable form of diagnosis of recurrent breast cancer after TRAM flap reconstruction remains fine-needle, core, or open biopsy if indicated.

Adult↗
PubMed2000

Cloning and characterisation of ITGAV, the genomic sequence for human cell adhesion protein (vitronectin) receptor alpha subunit, CD51.

The integrin family of receptors serves as major receptors for extracellular matrix-mediated cell adhesion and migration, cytoskeletal organisation, cell proliferation, survival, and differentiation. The alpha-V integrins consist of a subset which share a common alpha-V subunit combined with one of five beta subunits (beta-1, 3, 5, 6, or 8). The alpha-V integrins have been implicated in a number of developmental processes, including vasculogenesis and angiogenesis, and are therapeutic targets for inhibition of angiogenesis and osteoporosis. The human cDNA for alpha-V integrin (ITGAV) consists of a 5,717-bp transcript with a coding sequence (CDS) of 3,146 bp encoding a 150-kDa mature peptide. Here we describe the gene structure of ITGAV.

Antigens, CD↗
PubMed1999

An electrocardiographic algorithm for the prediction of the culprit lesion site in acute anterior myocardial infarction.

BACKGROUND: Although the 12-lead electrocardiogram (ECG) has been found useful in identifying the left anterior descending (LAD) coronary artery as the infarct-related artery in acute myocardial infarction (MI), it has traditionally been felt to be incapable of localizing the culprit lesion within the LAD itself. Such a capability would be important, because anterior MI due to proximal LAD lesions carry a much worse prognosis than those due to more distal or branch vessel lesions. HYPOTHESIS: This study investigated whether certain ECG variables--especially an ST-segment injury pattern in leads aVL and/or V1--would correlate with culprit lesion site, and an ECG algorithm was developed to predict culprit lesion site. METHODS: The initial ECGs of 55 patients who had undergone cardiac catheterization after an anterior or lateral MI were reviewed to identify the leads with an ST-segment injury pattern; the corresponding catheterization films were then reviewed to identify the location of the culprit lesion; and these separate findings were then compared. RESULTS: The sensitivity and specificity of an ST-injury pattern in aVL in predicting a culprit lesion before the first diagonal branch were 91 and 90%, respectively; the same values in predicting a lesion prior to the first septal branch were 85 and 78%. ST-segment elevation in V1, on the other hand, was a much less sensitive and specific predictor of a preseptal lesion. Overall, our algorithm correctly identified the culprit lesion location in 82% of our patients. CONCLUSION: Based on our findings, we conclude that a ST-segment injury pattern in aVL during an anterior myocardial infarction predominantly reflects a proximal LAD lesion and therefore constitutes a high-risk finding.

Algorithms↗
PubMed1999

Spontaneous intramural atrial hematoma presenting as a left atrial mass.

We describe an unusual case of spontaneously occurring intramural atrial hematoma with no communication with either atrium. The diagnosis of left atrial mass was made from transthoracic echocardiography. Subsequent examination with transesophageal echocardiography confirmed a large mass essentially filling the whole left atrium but failed to provide an etiologic diagnosis, which was eventually made at surgery.

Cardiac Surgical Procedures↗
PubMed1999

Mast cells of the bovine trachea: staining characteristics, dispersion techniques and response to secretagogues.

Sections of the lower trachea of cattle, fixed in either Carnoy's or formalin, were stained with toluidine blue, alcian blue, or alcian blue and safranin O to study the mast cell population. After toluidine blue staining, about twice as many cells in tissue fixed in Carnoy's contained dark blue granules compared with tissue fixed in formalin. In addition, for the first time in cattle, a population of cells containing red granules was identified after staining with alcian blue and safranin O. Most of these red granules were formalin sensitive. An enzymatic dispersal technique for mast cells is described that yielded 9.4+/-0.4% mast cells (percentage of nucleated cells) with a viability of 92.3+/-0.6%. Spontaneous histamine release was 3.3+/-0.8%. Dispersed mast cells were challenged with various immunological and nonimmunological secretagogues. The calcium ionophores, A23187, ionomyocin, and BrX537A, were effective in releasing up to 94% of histamine in mast cells in a dose-response relationship. Pasteurella haemolytica culture supernate caused about 10% histamine release at a dose of 0.5 mg/mL after correction for spontaneous release. The average histamine content of the mast cells was 6.6+/-1.0 pg/cell. Cytospins of dispersed cells fixed in Carnoy's and stained with alcian blue and safranin O contained mast cells with blue and red granules, and a few cells with a mixture of both granule types. Based on the effects of type of fixation, staining characteristics and histamine content, a mix of subtypes of mast cells is present in the bovine trachea. However, functionally they respond to secretagogues differently than rodent mast cells. Without an immunological secretagogue, studies to determine compounds that will be effective in blocking mast cell degranulation will be limited.

Animals↗
PubMed1997

Mast cell Fc epsilonRI expression in the rat intestinal mucosa and tongue is enhanced during Nippostrongylus brasiliensis infection and can be up-regulated by in vivo administration of IgE.

The activation of rodent and human mast cells can occur through the cross-linking of tetrameric IgE receptors each containing single alpha- and beta- and two gamma-subunits. However, the factors that regulate the in vivo expression of Fc epsilonRI are poorly understood. We have examined the expression of the Fc epsilonRI beta-subunit in the Nippostrongylus brasiliensis (Nb)-induced mode l of rat intestinal inflammation. We developed a double-staining technique for mast cell granules (Alcian blue) and the beta-subunit of Fc epsilonRI. The intensity of immunohistochemical staining per mast cell was quantified using an image analysis system. Jejunal and tongue mast cells of Lewis rats were visible by Alcian blue staining before Nb infection, but they expressed very low levels of beta-subunit as assessed by immunohistochemical staining. These levels were increased by day 11 postinfection and reached a maximum at day 14. Since serum IgE levels correlated well with the degree of beta-subunit expression, we investigated whether the observed enhancement of receptor expression might occur through the stabilization of receptor complexes by IgE. Therefore, Lewis rats were treated with myeloma IgE, and beta-subunit expression was examined. In both tongue and jejunal tissue, a significant rise in beta-subunit expression was observed in response to IgE injection, although levels of beta-subunit expression were not as high as those observed in Nb-infected animals. The increase in beta-subunit expression was accompanied by an increase in the amount of mast cell-associated IgE. These observations may have important implications for the regulation of IgE receptor expression during disease.

Animals↗
PubMed1997

Preparation of Schiff base adducts of phosphatidylcholine core aldehydes and aminophospholipids, amino acids, and myoglobin.

We have prepared Schiff base adducts of the core aldehydes of phosphatidylcholine and aminophospholipids, free amino acids, and myoglobin. The Schiff bases of the ethanolamine and serine glycerophospholipids were obtained by reacting sn-1-palmitoyl(stearoyl)-2-[9-oxo]nonanoyl-glycerophosphocholine (PC-Ald) with a twofold excess of the aminophospholipid in chloroform/methanol 2:1 (vol/vol) for 18 h at room temperature. The Schiff bases of the amino acids and myoglobin were obtained by reacting the aldehyde with an excess of isoleucine, valine, lysine, methyl ester lysine and myoglobin in aqueous methanol for 18 h at room temperature. Prior to isolation, the Schiff bases were reduced with sodium cyanoborohydride in methanol for 30 min at 4 degrees C. The reaction products were characterized by normal-phase high-performance liquid chromatography and on-line mass spectrometry with electrospray ionization. The amino acids and aminophospholipids yielded single adducts. A double adduct was obtained for myoglobin, which theoretically could have accepted up to 23 PC-Ald groups. The yields of the products ranged from 12 to 44% for the aminophospholipids and from 15-57% for the amino acids, while the Schiff base of the myoglobin was estimated at 5% level. The new compounds are used as reference standards for the detection of high molecular weight Schiff bases in lipid extracts of natural products.

Aldehydes↗
PubMed1997

Clinical features and outcome of patients admitted to the intensive care unit after plastic surgical procedures: implications for cost reduction and quality of care.

Recent interest in cutting cost and improving utilization and delivery of perioperative services has prompted surgeons to identify patient populations that would benefit from care in an intensive care unit as opposed to intermediate or standard care. The purpose of this study was to evaluate patients admitted to the surgical intensive care unit (SICU) after major plastic/reconstructive surgical procedures in order to determine appropriate perioperative management strategies for these patients. We reviewed retrospectively the data from 2,805 consecutive admissions to the SICU between 1990 and 1996. Forty-two patients (1.5%) who had undergone major plastic/reconstructive procedures were identified. Outcomes (mortality, length of stay in the SICU and hospital, and the degree of organ dysfunction) were compared between this population, an illness severity-matched (Acute Physiology and Chronic Health Evaluation [APACHE]-II and APACHE III) population of patients recovering from vascular surgical procedures, and a similarly matched population of SICU patients who were randomly assigned to serve as a second control group. The hospital mortality of the plastic surgical patient population (9.5%) was significantly higher than the zero mortality of the random cohort (p < 0.05). A second analysis compared the SICU plastics group to a case-controlled group of patients who were admitted to the postanesthesia care unit (PACU) for at least 24 hours of perioperative monitoring. SICU patients had significantly higher APACHE II scores (10.9) when compared to PACU patients (7.2; p < 0.01). Based on severity of illness scoring and eventual mortality, patients admitted to our SICU after major reconstructive surgery were selected appropriately for that setting. In contrast, the patients who stayed in the PACU for perioperative monitoring did not require life-supporting therapy and, therefore, were overmonitored. Care could be provided in a specialized unit with dedicated nursing specifically trained for that purpose.

APACHE↗
PubMed1994

The allosteric interaction between D-galactose and the Escherichia coli galactose repressor protein.

The Escherichia coli galactose repressor protein (GalR) inhibits transcription of the gal operon upon binding to two operator sites (1-7). This DNA binding activity is inhibited when D-galactose or D-fucose binds to GalR (8-14). Fluorescence spectroscopy was used to characterize the single tryptophan of GalR and to investigate the interaction between galactose and GalR. Fluorescence quenching experiments place both tryptophan residues of the GalR dimer in similar, solvent-exposed locations. Galactose is shown to enhance the intrinsic tryptophan fluorescence of GalR, the source of which is not explained by a change in decay times, but is due to an increase in the pre-exponential factor of the longest of the three fluorescence decay times. It is shown that the beta-anomer of D-galactose is the likely form that binds to GalR. An increase in pH from 6.3 to 9.5 causes the equilibrium association constant (K alpha) describing the galactose-GalR interaction to decrease 10-fold. The interaction is cooperative below pH 9.5. Over the pH range of 6.3 to 9.5, the tryptophan solvent exposure of GalR increases. Galactose binding also induces an increase in exposure. These results, and others presented in this paper, show that both pH and galactose cause global alterations in the structure of GalR.

Allosteric Regulation↗
PubMed1994

Oxyradical-induced antioxidant and lipid changes in cultured human cardiomyocytes.

Because the chronically cyanotic myocardium is thought to be more susceptible to oxyradical injury than the noncyanotic myocardium during cardiovascular surgery, we studied the oxyradical susceptibility of human ventricular cardiomyocytes cultured at high and low oxygen tension (PO2) levels. Passage 4 tetralogy of Fallot cardiomyocytes were cultured at PO2 levels of 150 and 40 mmHg for 14 days and then exposed for 10 min to superoxide radicals. The cellular levels of ATP, phospholipid fatty acids, phospholipid conjugated dienes, alpha-tocopherol, and activities of superoxide dismutase, catalase, and glutathione peroxidase were measured. ATP levels decreased more markedly in the low-PO2 group. Although the decrease in alpha-tocopherol levels was similar for both groups, phospholipid conjugated diene formation and phospholipid unsaturated fatty acid loss was greater in the low-PO2 cells. Glutathione peroxidase activity was rapidly inhibited. Superoxide dismutase activity was unaffected, and catalase activity was inhibited by no more than 50%. Although extracellular superoxide dismutase with catalase did not inhibit phospholipid conjugated diene formation and phospholipid breakdown, extracellular glutathione peroxidase with reduced glutathione did limit phospholipid damage. With the occurrence of membrane lipid peroxidation, the decreased glutathione peroxidase activity in the cyanotic tetralogy of Fallot myocardium determines cardiomyocyte membrane susceptibility to oxidant injury.

Cells, Cultured↗
PubMed1994

Measles outbreak in a tribal population of Thane district, Maharashtra.

In March 1992, an outbreak of measles, in the tribal population of Vavar village, Mokhada Taluk, Thane district, Maharashtra, was investigated. Two hamlets of Vavar village namely Sagpanipada (epidemic in October, November 1991) and Behedpada (epidemic in January, February 1992) were affected. In both hamlets, measles cases were confined to children below 10 yrs and 96% of the cases occurred in children below 6 yrs. Attack rates were 52.7% and 51.4% and case fatality rates were 31.2% and 15.6% at Sagpanipada and Behedpada, respectively. All the convalescent patients' sera possessed IgM antibodies against measles. A clear drop in IgM and a rise in IgG antibodies against measles was observed in 35 paired samples from convalescent patients. Fifty four per cent of sera from controls, possessed IgM antibodies. Migrating population appeared to have imported measles which flared up in an epidemic among the susceptibles. Priority immunization of the children of remote isolated populations may prevent such epidemics.

Child↗
PubMed1992

Cultured vascular endothelial cell susceptibility to extracellularly generated oxidant injury.

To understand better the effect of oxidant injury on vascular endothelial cells, human saphenous vein endothelial cells were cultured at atmospheric (pO2 of 150 mmHg) or low (pO2 of 40 mmHg) oxygen tensions. The cellular rates of growth, antioxidant enzyme activities (superoxide dismutase, catalase, and glutathione peroxidase), phospholipid fatty acids and cellular susceptibility to extracellularly generated oxidants (hypoxanthine-xanthine oxidase) were measured. The antioxidant enzyme activities were regulated by oxygen tension and significantly differed by day 14. The cells cultured at the low oxygen tension had significantly (P less than 0.01) lower antioxidant activities than the cells cultured at the high oxygen tension. The cells cultured at an oxygen tension of 150 mmHg were more resistant to shrinkage and lipid peroxidation from the oxidants than the cells cultured at a pO2 of 40 mmHg by day 14. Since arterial and venous endothelial cells are perfused with blood at a pO2 of 100 and 40 mmHg, respectively, the postcapillary venous endothelial cells should have lower antioxidant enzyme activities than the precapillary arterial endothelial cells.

Catalase↗
PubMed1992

Experience with a measles vaccine manufactured in India.

Five hundred and twenty seven children between 7 months and 2 years of age were vaccinated with measles vaccine manufactured by the Serum Institute of India. The sero-conversion rate in children who had no antibodies previous to vaccination was 98.4% as tested in HI. Ninety per cent of children who had pre-vaccination measles antibodies showed a two-fold or more rise in HI antibodies. The side reactions of the vaccine were negligible.

Antibodies, Viral↗