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Biomedical subjects

S J Shah

Publications and source records attributed to S J Shah.

At least 19 recordsLinked to original sources
PubMed2005

Effects of ultra-wideband electromagnetic pulses on pre-neoplastic mammary epithelial cell proliferation.

Electromagnetic ultra-wideband pulses (UWB) or nanopulses, are generated by a wide range of electronic devices used in communications and radar technology. However, the specific effects of nanopulse exposure on cell growth and function have not been extensively investigated. Here, studies have been conducted to determine the effects of prolonged exposure to non-ionizing, low to moderate intensity nanopulses on the growth of pre-neoplastic CL-S1 mammary epithelial cells in vitro. Cells were grown in culture and maintained in serum-free defined medium containing 10 ng/ml EGF and 10 microg/ml insulin as comitogens. Studies showed that 0.25-3.0 h exposure to nanopulses of 18 kV/m field intensity, 1 kHz repetition rate and 10 ns pulse width had no effect on CL-S1 cell growth or viability during the subsequent 72-h culture period. However, exposure to similar nanopulses for prolonged periods of time (4-6 h) resulted in a significant increase in cell proliferation, as compared to untreated controls. Additional studies showed that nanopulse exposure enhanced CL-S1 cell growth when cells were maintained in media containing only EGF, but had no effect on cells maintained in defined media that were mitogen-free or containing only insulin. Studies also showed that the growth-promoting effects of nanopulse exposure were associated with a relatively large increase in intracellular levels of phospho-MEK1 (active) and phospho-ERK1/2 (active) in these cells. These findings demonstrate that prolonged exposure to moderate levels of UWB enhanced EGF-dependent mitogenesis, and that this growth-promoting effect appears to be mediated by enhanced activation of the mitogen-activated protein kinase (MAPK) signalling pathway in pre-neoplastic CL-S1 mammary epithelial cells.

Animals↗
PubMed2002

Clinical, endocrine and metabolic studies in the kindred of familial partial lipodystrophy--a syndrome of insulin resistance.

OBJECTIVE: To study clinical, endocrine and metabolic profiles in the kindred of subjects with familial partial lipodystrophy (FPLD, Dunnigan type). MATERIAL AND METHODS: Twenty two relatives (10 males, 12 females), from an extended family with FPLD, were assessed for the phenotypic features, impaired glucose tolerance (IGT)/diabetes mellitus (DM), dyslipidemia and the presence of insulin resistance. Plasma glucose and serum lipids were measured using glucose oxidase and standard colorimetric methods. Serum insulin was estimated by radioimmunoassay. RESULTS: The age was 12 to 67 years, two being adolescents. Two of the 20 adults were overweight and eight were underweight; BMI (adults) was 15.5 to 28.5. Features of FPLD were evident among eight out of 12 women. This typical phenotype was not obvious in all 10 male members. Varying degree of Hirsuitism was observed in four of 12 women, acanthosis nigricans in 11 out of 22 members and skin tags were present in only eight of 22; hypertension in six members and diabetes in four. Eleven members had either impaired glucose tolerance (IGT) (n=7), or DM (n=4). Ten of 20 members showed hyperinsulinemic response on oral glucose tolerance test (OGTT). Dyslipidemia was present in 13 family members. CONCLUSION: The majority (2/3rd) of female members showed typical phenotypic features of FPLD, with a clustering of cardiovascular risk factors and insulin resistance syndrome. More than half the men without phenotypic features of FPLD had either IGT/DM, dyslipidemia, hypertension or cardiovascular disease.

Adolescent↗
PubMed2001

Relationship of p15 and p16 gene alterations to elevated dihydrofolate reductase in childhood acute lymphoblastic leukaemia.

The downstream effects of p15 and p16 gene deletions and loss of transcripts on dihydrofolate reductase (DHFR) were examined in 63 B-precursor (BP) acute lymphoblastic leukaemia (ALL) samples. p15 and/or p16 gene deletions were seen in 6% and 8%, respectively, of BP-ALL samples; however, losses of p15 and/or p16 transcripts were seen in 26 out of 63 (41%) samples. Loss of p15 transcripts (36.5%) exceeded that for p16 (17.5%). For the 26 BP-ALLs that lacked p15 and/or p16 transcripts, only six (23%) exhibited low levels of DHFR by flow cytometry assay with Pt430, a fluorescent anti-folate. Conversely, 18 out of 37 (49%) BP-ALL samples with intact p15 and/or p16 genes and transcripts showed low levels of DHFR (P = 0.04). In p15- and p16-null K562 cells transfected with a tetracycline-inducible p15 cDNA construct, induction of p15 transcripts and protein was accompanied by decreased growth rates, decreased S-phase fraction, decreased retinoblastoma protein phosphorylation, and markedly reduced levels of DHFR transcripts and protein. Collectively, our results suggest that losses of p15 and/or p16 gene expression result in elevated levels of DHFR in BP-ALL in children. However, additional downstream factors undoubtedly also contribute to elevated levels of this enzyme target.

Adolescent↗
PubMed1999

Uncoupling of in vivo torque production from EMG in mouse muscles injured by eccentric contractions.

1. The main objective of this study was to determine whether eccentric contraction-induced muscle injury causes impaired plasmalemmal action potential conduction, which could explain the injury-induced excitation-contraction coupling failure. Mice were chronically implanted with stimulating electrodes on the left common peroneal nerve and with electromyographic (EMG) electrodes on the left tibialis anterior (TA) muscle. The left anterior crural muscles of anaesthetized mice were stimulated to perform 150 eccentric (ECC) (n = 12 mice) or 150 concentric (CON) (n = 11 mice) contractions. Isometric torque, EMG root mean square (RMS) and M-wave mean and median frequencies were measured before, immediately after, and at 1, 3, 5 and 14 days after the protocols. In parallel experiments, nicotinic acetylcholine receptor (AChR) concentration was measured in TA muscles to determine whether the excitation failure elicited a denervation-like response. 2. Immediately after the ECC protocol, torque was reduced by 47-89 %, while RMS was reduced by 9-21 %; the RMS decrement was not different from that observed for the CON protocol, which did not elicit large torque deficits. One day later, both ECC and CON RMS had returned to baseline values and did not change over the next 2 weeks. However, torque production by the ECC group showed a slow recovery over that time and was still depressed by 12-30 % after 2 weeks. M-wave mean and median frequencies were not affected by performance of either protocol. 3. AChR concentration was elevated by 79 and 368 % at 3 and 5 days, respectively, after the ECC protocol; AChR concentration had returned to control levels 2 weeks after the protocol. At the time of peak AChR concentration in the ECC protocol muscles (i.e. 5 days), AChR concentration in CON protocol muscles was not different from the control level. 4. In conclusion, these data demonstrate no major role for impaired plasmalemmal action potential conduction in the excitation-contraction coupling failure induced by eccentric contractions. Additionally, a muscle injured by eccentric contractions shows a response in AChR concentration similar to a transiently denervated muscle.

Animals↗
PubMed1999

Simultaneous determination of cinnarizine and domepiridone maleate from tablet dosage form by reverse phase ion pair high performance liquid chromatography.

A new simple, precise, rapid and selective reverse phase ion pair high performance liquid chromatography (HPLC-RP) method has been developed for the simultaneous determination of cinnarizine (CINN) and domepiridone maleate (DOME) from tablets using acetonitrile-methanol-water-0.1 N sulfuric acid (37:10:48:5 v/v/v/v) containing sodium lauryl sulfate (0.01 M), as a mobile phase and a Machery Nagel nitrile column (10 microns, 25 cm x 4.0 mm i.d.) as the stationary phase. The flow of mobile phase through the column was kept at 1.0 ml min(-1) through out the analysis. Detection was carried out using a UV detector at 225 nm. The retention times for CINN and DOME were 4.73 and 9.41 min, respectively. The linearity range and percentage recoveries for CINN and DOME were 4 1000 and 60-750 microg ml(-1) and 99.90 and 99.60%, respectively.

Calcium Channel Blockers↗
PubMed1999

Sleep problems in emergency department patients with injuries.

OBJECTIVES: To assess trauma patients' frequency of sleep problems, to evaluate their injuries in the context of their sleep habits, and to determine how often ED health care workers (HCWs) inquire about sleep complaints. METHODS: This was a prospective observational study of patients evaluated in the ED for unintentional trauma. Patients answered a "sleep survey" that was reviewed for the amount and timing of sleep in the preinjury period and for indications of a sleep problem. Preinjury sleep characteristics were compared with the individual's usual habits, and the group's sleep features were compared with "normal" sleep and the prevalence of sleep problems in historical controls. RESULTS: Seventy patients were surveyed. Mechanisms and types of injury included motor vehicle collisions (MVCs), falls, lacerations, bruises, sprains, and fractures. The mean total sleep time in the preinjury period (6.9 hours) was significantly shorter than that obtained during usual weekday and weekend sleep. Twenty-four patients (34.3%) were at high risk for a sleep problem. Few patients thought a sleep problem contributed to the injury. No other ED HCW asked about the patient's sleep habits. CONCLUSIONS: Acute sleep deprivation in the preinjury period, and chronic sleep deprivation with a variety of other sleep problems are found in this patient population. Despite the association of sleep problems and certain types of injury (e.g., MVC), ED HCWs do not inquire about sleep in their initial ED evaluations. This important issue may be overlooked in trauma risk assessment and prevention.

Adolescent↗
PubMed1999

Rates of lower-extremity amputation and arterial reconstruction in the United States, 1979 to 1996.

OBJECTIVES: This report describes trends in the rates of lower-extremity amputation and revascularization procedures and vascular disease risk factors. METHODS: We analyzed trends in National Hospital Discharge Survey data for 1979 through 1996 and in National Health Interview Study data for 1983 through 1994. RESULTS: Despite a decline between 1983/84 and 1991/92, by 1995/96 the rate of major amputation had increased 10.6% since 1979/80. The earlier 12-year decline was positively correlated with reductions in the prevalence of smoking (r = 0.88, P < .0001), hypertension (r = 0.65, P = .02), and heart disease (r = 0.73, P = .007), but not diabetes (r = -0.33, P = .29). During the 1980s, amputation and angioplasty rates were inversely correlated (r = -0.75, P = .001), but the decline in amputation rates occurred before the increase in angioplasty. The major amputation rate, which has increased since 1993, was 24.95 per 100,000 people in 1996. CONCLUSIONS: Major amputation rates fell in the years following the diffusion of distal bypass surgery but before the widespread use of peripheral angioplasty. Because disease prevalence and primary amputation rates are unknown, it is difficult to estimate the contribution of recent improvements in vascular surgery to limb preservation.

Adult↗
PubMed1998

Simultaneous determination of pseudoephidrine HCl (PSE) and terfanidine (TER) from formulations by reversed-phase ion pair high-performance liquid chromatography (RP-HPLC).

A new simple, precise, rapid, and selective reversed-phase ion pair high-performance liquid chromatography (RP-HPLC) method has been developed for the simultaneous determination of pseudoephidrine (PSE) and terfanidine (TER) from tablets using 60:15:25 acetontrile:methanol:water (v/v) containing 2.9 g sodium lauryl sulfate/liter, pH adjusted to 3.1 using phosphoric acid as a mobile phase and C18 Spherisorb ODS 2 (3 microns, 5 cm x 4.6 mm i.d.) as stationary phase. Detection was carried out using a UV detector at 254 nm. A constant flow of 1.0 ml/min was maintained throughout the analysis. Retention times for PSE and TER were 1.90 and 7.35 min, respectively. Linearity range and percentage recoveries for PSE and TER were 24-1200 and 12-600 micrograms/ml, and 100.01 and 100.4%, respectively.

Calibration↗
PubMed1996

Immune thrombocytopenia and hemolytic anemia associated with Hodgkin disease.

PURPOSE: We discuss an unusual clinical presentation of Hodgkin disease with immune thrombocytopenia and autoimmune hemolytic anemia. PATIENTS AND METHODS: A 4-year-old boy presented to us with a large anterior mediastinal mass, thrombocytopenia, and Coombs' positive hemolytic anemia refractory to transfusion therapy. Biopsy of the anterior mediastinal mass was possible only after administration of intravenous immunoglobulin to raise the platelet count. The immune manifestations decreased with initiation of appropriate chemotherapy. RESULT: The child was able to successfully complete chemotherapy and radiation therapy and has no clinical or laboratory evidence of persistent autoimmune phenomena. CONCLUSION: Immune thrombocytopenia with autoimmune hemolytic anaemia is a rare presenting manifestation of Hodgkin disease and can present difficulty in diagnosis and management.

Anemia, Hemolytic, Autoimmune↗
PubMed1989

Fluorescence digital microscopy of interstitial macromolecular diffusion in burn injury.

Computer vision techniques implemented on an IBM PC/AT have been applied to the study of microvascular permeability and interstitial diffusion in dorsal skin flap chamber preparations of hamsters. Experimental data was obtained for the leakage of fluorescent labelled dextran (70,000 daltons) after a precisely controlled mild degree of localized thermal trauma and compared with control data acquired prior to burn injury. Computer vision analysis techniques were applied to convert the fluorescent images into two-dimensional concentration maps. Interstitial diffusion coefficient values were computed from measured extravascular concentration profiles around a vessel of interest, assuming cylindrical or rectangular geometry, and optimally fitting a diffusion model to the data. An increase in the apparent diffusivity after mild thermal trauma was observed. Novel techniques were applied to solve hardware problems related to data acquisition and analysis, and a new library of software was developed to handle specific image processing requirements.

Animals↗
PubMed1987

Incompatibility of Hexabrix and papaverine in peripheral arteriography.

A case is reported in which a previously patent artery became temporarily occluded during angiography. The authors believe it happened because of incompatibility of the contrast agent ioxaglate (Hexabrix) and papaverine. Extreme caution is recommended whenever a new low-osmolality contrast agent is used in conjunction with a pharmacoangiographic agent.

Angiography↗