Biomedical subjects

I Syed

Publications and source records attributed to I Syed.

8 recordsLinked to original sources

PubMed2006

Coronary calcification and osteoporosis in men and postmenopausal women are independent processes associated with aging.

The objective of this study was to investigate whether low bone mass is directly associated with the severity of coronary atherosclerosis in men and postmenopausal women self-referred for evaluation of coronary atherosclerosis and osteoporosis. Low bone mass was evaluated by measurement of bone mineral density (BMD) using quantitative computerized tomography (QCT). Coronary atherosclerosis was evaluated by measurement of coronary calcium (CC) burden using electron beam computerized tomography (EBCT). Using a cross-sectional design, we tested the hypothesis that osteoporosis and coronary atherosclerosis are correlated, age-dependent processes. Study variables were BMD, CC scores, and other known risk factors for osteoporosis and atherosclerosis. Qualifying for the study were 313 postmenopausal women and 167 men. Men had higher baseline CC scores and higher body mass indexes compared to women. In females, those patients with coronary calcification were older and had significantly lower BMD compared to those without calcification. In males, those patients with coronary calcification were older. By univariate correlation analysis, the degree of coronary calcification was inversely associated with BMD in postmenopausal women (P < 0.0001) but not in men. However, after controlling for age, this association was absent for both men and postmenopausal women. Using multivariate logistic regression analysis in women and men separately, age was the only significant predictor of positive CC status and low BMD. Our study suggests that in postmenopausal women and in men, after controlling for age, osteoporosis and coronary atherosclerosis are independent processes.

Aging↗

PubMed2006

99mTechnetium-mercaptoacetyltriglycine scintigraphy with full bladder in patients with severe bladder dysfunction.

PURPOSE: We evaluated 99mtechnetium-mercaptoacetyltriglycine scintigraphy for detecting threshold bladder volume at which upper tract obstruction occurs in patients with bladder dysfunction. MATERIALS AND METHODS: A total of 24 patients 19 to 74 years old with severe bladder dysfunction who underwent 99mtechnetium-mercaptoacetyltriglycine scintigraphy and videocystometrogram in a 4-year period were selected for retrospective study. 99mTechnetium-mercaptoacetyltriglycine scintigraphy was done with a full bladder with a mean instilled volume of more than 850 ml saline. In patients in whom an obstructed renal outflow pattern was observed saline was drained at a rate of 100 ml every 5 minutes while dynamic imaging was performed. If results were abnormal, the study was repeated with an empty bladder. Differential function, parenchymal transit time index and outflow efficiency were calculated. RESULTS: Of the 24 patients 15 had an obstructed outflow pattern with a full bladder, which was relieved at a bladder volume of less than 390 ml (median 300, range 250 to 600). Only 2 of these 15 patients had a normal vesical end filling pressure of less than 20 cm H2O. There was no obstruction in 9 patients, of whom 5 had increased vesical end filling pressures. Followup in patients who had normal tracer outflow on a full bladder showed no decrease in renal function, while a small decrease was seen in patients who had obstructed outflow on a full bladder. CONCLUSION: This novel, full bladder 99mtechnetium-mercaptoacetyltriglycine scintigraphic technique provides the ability to detect bladder volumes at which obstructive outflow patterns develop in patients with severe bladder dysfunction.

Adult↗

PubMed2004

Vertebral osteomyelitis without disc involvement.

Vertebral osteomyelitis is most commonly due to pyogenic or granulomatous infection and typically results in the combined involvement of the intervertebral disc and adjacent vertebral bodies. Non-infective causes include the related conditions of chronic recurrent multifocal osteomyelitis (CRMO) and SAPHO (synovitis, acne, pustulosis, hyperostosis, and osteitis) syndrome. Occasionally, these conditions may present purely within the vertebral body, resulting in various combinations of vertebral marrow oedema and sclerosis, destructive lesions of the vertebral body and pathological vertebral collapse, thus mimicking neoplastic disease. This review illustrates the imaging features of vertebral osteomyelitis without disc involvement, with emphasis on magnetic resonance imaging (MRI) findings.

Humans↗

PubMed2001

Sulfate and chloride transport in Caco-2 cells: differential regulation by thyroxine and the possible role of DRA gene.

The current studies were undertaken to establish an in vitro cellular model to study the transport of SO and Cl(-) and hormonal regulation and to define the possible function of the downregulated in adenoma (DRA) gene. Utilizing a postconfluent Caco-2 cell line, we studied the OH(-) gradient-driven (35)SO and (36)Cl(-) uptake. Our findings consistent with the presence of an apical carrier-mediated (35)SO/OH(-) exchange process in Caco-2 cells include: 1) demonstration of saturation kinetics [Michaelis-Menten constant (K(m)) of 0.2 +/- 0.08 mM for SO and maximum velocity of 1.1 +/- 0.2 pmol x mg protein(-1) x 2 min(-1)]; 2) sensitivity to inhibition by DIDS (K(i) = 0.9 +/- 0.3 microM); and 3) competitive inhibition by oxalate and Cl(-) but not by nitrate and short chain fatty acids, with a higher K(i) (5.95 +/- 1 mM) for Cl(-) compared with oxalate (K(i) = 0.2 +/- 0.03 mM). Our results also suggested that the SO/OH(-) and Cl(-)/OH(-) exchange processes in Caco-2 cells are distinct based on the following: 1) the SO/OH(-) exchange was highly sensitive to inhibition by DIDS compared with Cl(-)/OH(-) exchange activity (K(i) for DIDS of 0.3 +/- 0.1 mM); 2) Cl(-) competitively inhibited the SO/OH(-) exchange activity with a high K(i) compared with the K(m) for SO, indicating a lower affinity for Cl(-); 3) DIDS competitively inhibited the Cl(-)/OH(-) exchange process, whereas it inhibited the SO/OH(-) exchange activity in a mixed-type manner; and 4) utilizing the RNase protection assay, our results showed that 24-h incubation with 100 nM of thyroxine significantly decreased the relative abundance of DRA mRNA along with the SO/OH(-) exchange activity but without any change in Cl(-)/OH(-) exchange process. In summary, these studies demonstrated the feasibility of utilizing Caco-2 cell line as a model to study the apical SO/OH(-) and Cl(-)/OH(-) exchange processes in the human intestine and indicated that the two transporters are distinct and that DRA may be predominantly a SO transporter with a capacity to transport Cl(-) as well.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗

PubMed1998

Identification of the sensory/motor area and pathologic regions using ECoG coherence.

An electrophysiologic mapping technique which enables identification of the central sulcus and pathologic cortical regions is described. Electrocorticographic recordings of 1 min duration were recorded from 25 patients who were undergoing resection of tumors in the sensory-motor region or being evaluated for temporal lobectomy for epilepsy. Analysis of the patterns of subdural inter-electrode coherence revealed low coherence across the central sulcus for 11/12 cases where its location could be verified with direct cortical stimulation and/or somatosensory evoked potential mapping. Regions of high coherence identified the location of tumors in the sensory-motor region for 10/10 cases. Over the temporal lobe, localized areas of high coherence were evident in 8/9 epilepsy patients, but were not indicative of the location of mesial temporal lobe tumors or inter-ictal spiking, when present. We conclude that analysis of cortical coherence patterns may be helpful for revealing the location of pathologic processes relative to critical cortical areas.

Adolescent↗

PubMed1996

Intestinal distribution of human Na+/H+ exchanger isoforms NHE-1, NHE-2, and NHE-3 mRNA.

The identity of Na+/H+ exchanger (NHE) isoforms in the human small intestine and colon and their role in vectorial Na+ absorption are not known. The present studies were undertaken to examine the regional and vertical axis distribution of NHE-1, NHE-2, and NHE-3 mRNA in the human intestine. Ribonuclease protection assays were used to quantitate the levels of mRNA of these isoforms in various regions of the human intestine. In situ hybridization technique was used to localize NHE-2 and NHE-3 mRNA in the colon. The NHE-1 isoform message was present uniformly throughout the length of the human intestine. In contrast, mRNA levels for human NHE-2 and NHE-3 isoforms demonstrated significant regional differences. The NHE-3 abundance was found in decreasing order: ileum > jejunum > proximal colon = distal colon. The NHE-2 message level in the distal colon was significantly higher than in the proximal colon but was evenly distributed in the small intestine. In addition, NHE-2 mRNA was present in surface epithelial cells as well as in cells of the crypt region, suggesting the presence of NHE-2 message throughout the vertical axis of the colonic crypts. In contrast, NHE-3 mRNA was localized to surface colonocytes in the proximal colon. On the basis of this tissue-specific localization of NHE-2 and NHE-3 mRNA, it can be speculated that the relative contribution of NHE-2 and NHE-3 isoforms in Na+ absorption in the human intestine may be region specific, and these putative apical isoforms may be differentially regulated.

Amino Acid Sequence↗

PubMed1995

Displaying electrocorticographic findings on gyral anatomy.

Human electrocorticographic findings recorded from subdural arrays of electrodes were topographically mapped directly onto magnetic resonance images of gyral anatomy. With this technique gyri involved in generating somatosensory evoked potentials and epileptic phenomena are easily identified. Regions of the cortex which exhibit local spectral changes associated with cognitive tasks can also be visualized. These composite images of structure and function can provide insight regarding the functional organization of human cortex in relation to gyral anatomy and localized pathologic rhythms.

Brain Mapping↗

PubMed1981

Simultaneous markers for fluid and solid gastric emptying: new variations on an old theme: concise communication.

Radiotracer techniques for the assessment of gastric emptying have become popular in the past 6 yr. A new double-nuclide technique, for the simultaneous tagging of the solid and fluid phases, is described. Technetium-99m sulfur colloid (Tc-99m SC) is used in a manner similar to that described by Meyer and colleagues, but the new technique does not involve the use of live chickens, a significant advantage over the earlier procedures. Several fluid-phase radionuclides were tested to be used in conjunction with the Tc-99m SC. Indium-111 DTPA was found to be the only compatible fluid-phase agent. This new double-tracer technique promises to be safe, economical, simple, and physiologically sound.

Animals↗