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Biomedical subjects

S Gupta

Publications and source records attributed to S Gupta.

At least 127 records · Page 7Linked to original sources
PubMed2004

Development and experimental validation of a three-dimensional finite element model of the human scapula.

A new modelling approach, using a combination of shell and solid elements, has been adopted to develop a realistic three-dimensional finite element (FE) model of the human scapula. Shell elements were used to represent a part of the compact bone layer (i.e. the outer cortical layer) and the very thin and rather flat part of the scapula--infraspinous fossa and supraspinous fossa respectively. Solid elements were used to model the remaining part of the compact bone and the trabecular bone. The FE model results in proper element shapes without distortion. The geometry, material properties and thickness were taken from quantitative computed tomography (CT) data. A thorough experimental set-up for strain gauge measurement on a fresh bone serves as a reference to assess the accuracy of FE predictions. A fresh cadaveric scapula with 18 strain gauges fixed at various locations and orientations was loaded in a mechanical testing machine and supported at three locations by linkage mechanisms interconnected by ball joints. This new experimental set-up was developed to impose bending and deflection of the scapula in all directions unambiguously, in response to applied loads at various locations. The measured strains (experimental) were compared to numerical (FE) strains, corresponding to several load cases, to validate the proposed FE modelling approach. Linear regression analysis was used to assess the accuracy of the results. The percentage error in the regression slope varies between 9 and 23 per cent. It appears, as a whole, that the two variables (measured and calculated strains) strongly depend on each other with a confidence level of more than 95 per cent. Considering the complicated testing procedure on a fresh sample of scapula, the high correlation coefficients (0.89-0.97), the low standard errors (29-105 micro epsilon) and percentage errors in the regression slope, as compared to other studies, strongly suggest that the strains calculated by the FE model can be used as a valid predictor of the actual measured strain. The model is therefore an alternative to a rigorous three-dimensional model based on solid elements only, which might often be too expensive in terms of computing time.

Aged↗
PubMed2004

Plasma concentrations of tumour dimeric pyruvate kinase are increased in patients with chronic cardiac failure.

BACKGROUND: The aim of the study was to assess the effect of chronic cardiac failure (CCF) on circulating plasma concentrations of tumour metabolic marker dimeric pyruvate kinase type M2 (M2-PK). METHODS: Fifty patients with clinically stable CCF were studied. Patients with a history of past or ongoing malignancy were excluded. Dimeric M2-PK was measured by enzyme-linked immunosorbent assay in EDTA plasma. RESULTS: Dimeric M2-PK concentration increased significantly (P = 0.005) with increasing clinical severity of CCF as assessed by the New York Heart Association classification grade. CONCLUSIONS: Chronic cardiac failure results in an increased circulating plasma concentration of M2-PK, probably related to increased glycolytic flux. The physiological significance of the results is at present unclear but may relate to maintaining a balance between energy production and the supply of glycolytic intermediates to maintain synthetic processes. The results of this investigation will also have significance in the clinical interpretation of M2-PK concentrations.

Adult↗
PubMed2004

Primary non-Hodgkin's lymphoma of the bone: a single institution experience.

UNLABELLED: Primary non-Hodgkin's lymphoma of the bone is an unusual entity. Twenty-five patients with diffuse large cell lymphoma of the bone were registered at the Tata Memorial Hospital (TMH) from August, 1991, to May, 2002. Pain at the local site and soft tissue swelling were the commonest symptoms. Involvement of the bones in the lower half of the body was more frequent than the bones in the upper half. Osteolytic lesions and an associated soft tissue mass were the common radiological findings. Nineteen patients received CHOP chemotherapy and five received COP chemotherapy. Twenty-three patients received involved field radiotherapy. The overall response to therapy was 96%. On follow-up, two patients had a nodal relapse. One patient died of progressive disease, and one patient died of cryptococcal meningitis. There were no deaths due to treatment-related toxicity. The mean progression free survival was 9.39 yr and the overall survival was 11.66 yr. The median overall survival has not been reached. At last follow-up, 21 patients were being following up at TMH and are free of disease. CONCLUSION: Primary bone lymphoma is a malignancy that is highly curable with a combination of chemotherapy and radiotherapy.

Adolescent↗
PubMed2004

Technical note: effect of corticotropin-releasing hormone on adrenocorticotropic hormone and cortisol in steers.

The objective of this study was to determine an appropriate exogenous dose of bovine corticotropin-releasing hormone (bCRH) to stimulate the physiological effects of the hypothalamic-pituitary-adrenal axis in steers as a method to test the sensitivity of the pituitary and adrenal gland. Twenty 14-mo-old Holstein-Friesian steers were blocked by weight (443.7+/-2.5 kg) and randomly allotted to receive either saline (control) or bCRH (0.1, 0.3, 1.0, or 1.5 microg/kg BW). Animals were housed in a slatted-floor facility (n = 5 per pen). Indwelling jugular catheters, for both the administration of bCRH and blood collection, were fitted on d -1 of the experiment. Saline and bCRH were administered i.v. at time 0. Serial blood samples were collected at -15, 0, 15, 30, 45, 60, 75, 90, 105, 120, 135, 150, 165, and 180 min relative to time 0. Following administration of 0.1 microg of bCRH/kg BW, the peak ACTH response was not significantly different from pretreatment baseline concentrations (mean concentrations as measured at -15 and 0 min before bCRH administration). Mean ACTH concentrations from 0 to 180 min following 0.1 microg of bCRH/kg BW were not significantly different (P = 0.177) from controls. Administration of 0.3, 1.0, and 1.5 microg of bCRH/kg BW increased (P < 0.05) peak ACTH above pretreatment concentrations, and mean ACTH from 0 to 180 min for these treatments were greater (P < 0.05) than for controls. Peak cortisol responses to all bCRH treatments were greater (P < 0.05) than those to pretreatment concentrations. Mean cortisol concentrations from 0 to 180 min were greater (P < 0.05) in all bCRH-treated steers than in controls, but there were no significant differences among the bCRH treatments. The ratio of mean cortisol to mean ACTH for all bCRH doses tested differed (P < 0.05) from control values, indicating reactivity of the adrenals. In conclusion, bCRH challenge may be a useful method for testing the sensitivity of the hypothalamic-pituitary-adrenal axis in steers subjected to stressful husbandry conditions, and a minimum dose of 0.3 microg of bCRH/kg BW is required to stimulate physiological effects of stressor hormones.

Adrenocorticotropic Hormone↗
PubMed2004

Inhibition of skin sphingosine synthesis: enhanced percutaneous permeation of 5-fluorouracil.

The present study was designed to investigate the role of skin sphingosine inhibition in enhancing the transcutaneous permeation of 5-fluorouracil (5-FU), a hydrophilic drug, across rat skin. Ethanol-perturbation significantly reduced the sphingosine content as compared to that in normal skin until 24 h of perturbation (p < 0.05). To maintain the low content of sphingosine for a longer time, beta-chloroalanine (beta-CA), a selective inhibitor of serine palmitoyl transferase, was used for inhibiting the sphingosine synthesis in viable skin. Application of beta-CA (600 microg or 1200 microg/7 cm2) to viable skin perturbed with ethanol significantly reduced the sphingosine content until 48 h as compared to that in perturbed viable skin (p < 0.05). However, the sphingosine content in viable skin perturbed with ethanol and treated with lower doses (200 or 400 microg/7 cm2) of beta-CA, returned significantly close to that in ethanol-perturbed viable skin at 36 h (p < 0.05). Skin sphingosine synthesis inhibition efficacy of 1200 microg beta-CA was insignificantly different to that of 600 microg dose of beta-CA at 36 h or 48 h (p < 0.05). The systemic delivery of percutaneously applied 5-FU across ethanol-perturbed rat skin treated with either 600 microg or 1200 microg beta-CA was significantly greater as compared to that obtained after oral administration or after application of lower percutaneous doses of beta-CA (p < 0.05). Higher Cmax, MRT, AUC and maintenance of effective plasma concentration of 5-FU for 46 h was achieved by a single topical application of a formulation containing 5-FU and 600 microg beta-CA to ethanol-perturbed skin.

Administration, Oral↗
PubMed2004

Directly observed therapy for tuberculosis in New York City: factors associated with refusal.

OBJECTIVES: To describe patients who utilize hospital-based directly observed therapy (DOT) programs and to describe factors that influence refusal of DOT. METHODS: Retrospective analysis of patients diagnosed with tuberculosis through hospital admission in 1997 at 12 hospital sites with out-patient DOT programs. Data were obtained from hospital patient records and from the New York City Tuberculosis Case Registry. RESULTS: Of 443 patients diagnosed with tuberculosis in 1997 at the 12 hospital sites and available and/or eligible for DOT, 52 (12%) refused DOT. The two main reasons for DOT refusal were that the patients felt they could self-medicate (21%) and that their work schedule interfered with a DOT program (19%). White non-Hispanic race/ethnicity was associated with refusal of DOT (P = 0.001). Conversely, interview for DOT while in the hospital (P < 0.001) and enrollment in drug treatment were associated with acceptance of DOT (P = 0.05). The five hospitals with tuberculosis clinics on site had the lowest percentages (0-9%) of patients refusing DOT. CONCLUSION: To increase patient acceptance of DOT, programs need flexible hours that accommodate patients in the workforce. Patient education should focus on the difficulty of completing tuberculosis treatment on a self-administered regimen and the importance of the support offered through DOT.

Adolescent↗
PubMed2004

Severe head injury in children: geographical range of an emergency neurosurgical practice.

OBJECTIVE: To determine the timings of regional transfer for emergency neurosurgery and intensive care after severe head injury in children, and the effective operational range of a regional service. DESIGN: Prospective observational study of admissions to a regional paediatric intensive care unit (PICU). SETTING: East Anglia region in England, January 2000 to December 2001, where 18 referring hospitals are within two hours road transit time from the centre. PATIENTS: 69 severely head injured children (52 boys and 17 girls, aged 8.4 (3.6 to 12.5) years). MAIN OUTCOME MEASURES: Time interval between injury and arrival at first hospital (primary transfer); timing between arrival at first hospital and arrival in PICU or the operating theatre (secondary transfer). RESULTS: Arrival in one of the 19 accident and emergency departments occurred (median, IQR) within 48 (35 to 70) minutes of the accident. After arrival, the interval of secondary transfer was 4.4 (3.2 to 5.8) hours. Children rarely received their surgery within four hours of injury; for this to occur, the geographical range of this regional practice would need to be restricted to those hospitals within about 45 minute road transit time from the centre. CONCLUSIONS: Good evidence supporting the recommendation that acute neurosurgery for the evacuation of a haematoma within four hours of injury is still scarce. The timings of care after an accident suggest that this guideline is unworkable in regions covering areas with road distance travel times in excess of 45 minutes.

Catchment Area, Health↗
PubMed2004

Influence of histamine and H1-receptor antagonists on ejaculated human spermatozoa: role of intrasperm Ca2+.

Histamine reduced sperm viability in a dose- and time-dependent manner, accompanied by rise in intrasperm Ca2+. Further, 2',4'-dichlorobenzamil hydrochloride (DBZ), a Na+-Ca2+ exchange inhibitor, known to elevate intrasperm Ca2+, potentiated both, elevation of intrasperm Ca2+ and spermicidal action of histamine. Pretreatment of sperm with very low doses of H1-receptor antagonists (chlorpheniramine, promethazine or diphenhydramine) prevented the histamine-induced elevation of intrasperm Ca2+ as well as its spermicidal action. However, pretreatment with famotidine, a H2-receptor antagonist did not produce such a protective action. The results strongly suggest that histamine elicits its spermicidal action via H1-receptors present on sperm cells.

Calcium↗
PubMed2004

A preliminary survey of patients' views on awareness, information, choices and expectations in women undergoing hysterectomy.

A questionnaire-study was undertaken among 50 women to take note of their views on awareness, information, choices and expectations on various aspects of hysterectomy performed on them. Most women (92%) did not know the type of hysterectomy and none of them was offered the alternative treatment, various types of hysterectomy done, type of anaesthesia used and hormone replacement therapy. A total of 96% wanted the surgeon to spend time with them explaining to them about various aspects of surgery and 46% thought the staff was sympathetic to them. A total of 26 women (52%) preferred to solve their problems with self-help groups (association of women with similar problems) and 84% wanted a leaflet to be distributed to them about various aspects of hysterectomy. This study concluded that Indian women to be involved in the decision making about their healthcare.

Adult↗
PubMed2003

Observation of Bose-Einstein condensation of molecules.

We have observed Bose-Einstein condensation of molecules. When a spin mixture of fermionic 6Li atoms was evaporatively cooled in an optical dipole trap near a Feshbach resonance, the atomic gas was converted into 6Li2 molecules. Below 600 nK, a Bose-Einstein condensate of up to 900 000 molecules was identified by the sudden onset of a bimodal density distribution. This condensate realizes the limit of tightly bound fermion pairs in the crossover between BCS superfluidity and Bose-Einstein condensation.

Journal Article↗
PubMed2003

Fiftyfold improvement in the number of quantum degenerate fermionic atoms.

We have produced a quantum degenerate 6Li Fermi gas with up to 7 x 10(7) atoms, an improvement by a factor of 50 over all previous experiments with degenerate Fermi gases. This was achieved by sympathetic cooling with bosonic 23Na in the F=2, upper hyperfine ground state. We have also achieved Bose-Einstein condensation of F=2 sodium atoms by direct evaporation.

Journal Article↗
PubMed2003

Radio-frequency spectroscopy of ultracold fermions.

Radio-frequency techniques were used to study ultracold fermions. We observed the absence of mean-field "clock" shifts, the dominant source of systematic error in current atomic clocks based on bosonic atoms. This absence is a direct consequence of fermionic antisymmetry. Resonance shifts proportional to interaction strengths were observed in a three-level system. However, in the strongly interacting regime, these shifts became very small, reflecting the quantum unitarity limit and many-body effects. This insight into an interacting Fermi gas is relevant for the quest to observe superfluidity in this system.

Journal Article↗
PubMed2003

Escitalopram, the S-(+)-enantiomer of citalopram, is a selective serotonin reuptake inhibitor with potent effects in animal models predictive of antidepressant and anxiolytic activities.

OBJECTIVE: The pharmacological profile of escitalopram, the S-(+)-enantiomer of citalopram, was studied and compared with citalopram and the R-(-)-enantiomer, R-citalopram. METHODS: Inhibition of the serotonin transporter (5-HTT) was studied in COS-1 cells expressing the human 5-HTT (h-5-HTT) and in rat brain synaptosomes. In vitro selectivity was studied relative to noradrenaline transporter (NAT) and dopamine transporter (DAT) function in rat brain synaptosomes, and affinities for other binding sites were determined. In vivo 5-HT activity was measured as inhibition of neuronal firing rate in rat dorsal raphe nucleus (DRN) and enhancement of 5-hydroxytryptophan (5-HTP)-induced behaviour (mouse and rat). Furthermore, studies were conducted in models of antidepressant (mouse forced-swim test), anxiolytic [foot-shock-induced ultrasonic vocalization (USV) in adult rats and mouse black and white box] and anti-aggressive activity (socially isolated mice). RESULTS: Escitalopram inhibited 5-HTT functions approximately 2 times more potently than citalopram and at least 40 times more potently than R-citalopram. Escitalopram showed insignificant activity at other monoamine transporters and 144 other binding sites. Escitalopram inhibited 5-HT neuronal firing in DRN and potentiated 5-HTP-induced behaviours more potently than citalopram; R-citalopram was inactive. Escitalopram and citalopram, but not R-citalopram, reduced forced-swimming-induced immobility and facilitated exploratory behaviour in the black and white box. Escitalopram and citalopram inhibited USV potently; R-citalopram was several times less potent. Escitalopram, citalopram and R-citalopram inhibited aggressive behaviour weakly. Escitalopram and citalopram had very potent anti-aggressive effects when co-administered with l-5-HTP. CONCLUSION: Escitalopram is a very selective 5-HT reuptake inhibitor. It is more potent than its racemate citalopram and is effective in animal models predictive of antidepressant and anxiolytic activities.

Action Potentials↗
PubMed2003

Synthesis and antifilarial evaluation of N1,Nn- xylofuranosylated diaminoalkanes.

A series of N(1),N(n)-xylofuranosylated diaminoalkanes (3-9 and 11-18) has been synthesized either by reductive amination of deoxy xylouloses (2a, 2b) with amines followed by one pot reduction with NaBH(4) or NaCNBH(3); or by 1,4-conjugate addition of amines to glycosyl olefinic esters (10a, 10b). The compounds were screened for their interference with filarial worms' glutathione metabolism, a potential target for chemotherapeutic attack. Interestingly, these compounds affected intracellular glutathione, gamma-glutamyl cysteine synthetase, glutathione reductase and glutathione-S-transferase(s) of bovine filarial worms to varying degrees. Some of the compounds though effected the motility and MTT reduction potential of filarial worms Brugia malayi, however, little microfilaricidal and macrofilaricidal were noted with compounds at 50mg/kg oral dose. Compounds 6, 16 and 17 were evaluated also for in vivo activity.

Alkanes↗
PubMed2003

Transventricular paraganglioma of the larynx.

Laryngeal paragangliomas are rare neuroendocrine tumours. Most laryngeal paragangliomas are supraglottic in location, with only 3% reported to be glottic in location. We present a rare case of transventricular paraganglioma with fixation of the hemilarynx that presented a diagnostic and therapeutic challenge.

Female↗
PubMed2003

Sodium Bose-Einstein condensates in the F = 2 state in a large-volume optical trap.

We have investigated the properties of Bose-Einstein condensates of sodium atoms in the upper hyperfine ground state. Condensates in the high-field seeking [F=2, m(F)=-2> state were created in a large volume optical trap from initially prepared [F=1, m(F)=-1> condensates using a microwave transition at 1.77 GHz. We found condensates in the stretched state [F=2, m(F)=-2> to be stable for several seconds at densities in the range of 10(14) atoms/cm(3). In addition, we studied the clock transition [F=1, m(F)=0> --> [F=2, m(F)=0> in a sodium Bose-Einstein condensate and determined a density-dependent frequency shift of (2.44+/-0.25+/-0.5) x 10(-12) Hz cm(3).

Journal Article↗
PubMed2003

Unusual origin of the flexor digiti minimi brevis muscle.

An unusual origin of the flexor digiti minimi brevis muscle of the right hand was discovered during cadaveric dissection. The muscle originated from the anterior aspect of the transverse fibers of the distal antebrachial fascia and inserted onto the base of the fifth proximal phalanx. When traction was applied to the proximal portion of the muscle, flexion was produced at the fifth metacarpophalangeal joint. Other intrinsic muscles of the hand and the muscles of the flexor forearm compartment had normal morphology. Although muscular anomalies in the hypothenar region have been described, the muscular variant described here was distinct in its origin and size from those previously reported. Knowledge of anomalous muscles in the hand has important clinical significance in routine surgery and in determining associated pathology.

Aged↗