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Biomedical subjects

A Sharma

Publications and source records attributed to A Sharma.

At least 91 records · Page 5Linked to original sources
PubMed2004

Ultrasound-guided infraclavicular axillary vein cannulation for central venous access.

BACKGROUND: Infraclavicular axillary vein cannulation is not commonly used for central venous access because identifying the surface landmarks is difficult. Ultrasound guided axillary vein puncture has not been well described. We assessed ultrasound imaging to guide catheterization of the infraclavicular axillary vein. METHODS: In 200 consecutive patients we attempted to catheterize the axillary vein using ultrasound imaging. After successful venepuncture, a tunnelled Hickman line was inserted for long-term central venous access. Surface landmarks of the skin puncture site were measured below the clavicle. We measured the depth of the vein from the skin, the length of the guidewire from skin to carina and the final length of catheter that was inserted. RESULTS: The axillary vein was successfully punctured with the help of ultrasound imaging with first needle pass in 76% of patients. The axillary vein was catheterized successfully in 96% of the cases. Guidewire malposition was detected and corrected by fluoroscopy in 15% of cases. Complications included axillary artery puncture in three (1.5%) and transient neuralgia in two (1%) cases. CONCLUSION: Ultrasound-guided catheterization of the infraclavicular axillary vein is a useful alternative technique for central venous cannulation with few complications.

Adolescent↗
PubMed2004

Cyclical elongation regulates contractile responses of isolated airways.

Bronchoconstrictor responses are quantitatively different when they are evoked under static conditions and during or after periods of deep inspiration. In vivo, deep inspirations produce bronchodilation and protect the lung from subsequent bronchoconstriction (termed bronchoprotection). These effects may be due in part to dynamic stretch on airways produced by cyclical expansion of airway diameter. However, airways also lengthen cyclically during breathing. The effects of cyclical airway elongation on evoked bronchoconstriction have not been examined. This study recorded evoked contractions of pig bronchial segments 1) at different airway lengths, 2) after a period of cyclical lengthening in relaxed airways, and 3) during cyclical lengthening in pretoned airways. Airway segments were mounted in organ baths and bathed in Krebs solution luminally and on the adventitia. Airways were cyclically lengthened by 5-30% of their deflated length at 0.5-2 Hz for 5 min. Contractions were evoked by electrical field stimulation or carbachol and were recorded under isovolumic conditions. Under static conditions, there was a blunt relationship between length and response to electrical field stimulation. After a period of airway length cycling, electrical field stimulation-induced contractions were increased. In airways pretoned with carbachol, cyclical lengthening produced a transient bronchodilation and a sustained increase in contraction. Contractile responses were not blocked by indomethacin. The results show that isolated airways respond actively to dynamic changes in length. Our results indicate that cyclical lengthening of airways could contribute to lung function in vivo but does not appear to account for the phenomenon of bronchoprotection.

Animals↗
PubMed2004

Many paths to dewetting of thin films: anatomy and physiology of surface instability.

The role of essential, real life thin film complexities such as antagonistic (attractive and repulsive) interactions, retardation of van der Waals force, substrate and film heterogeneities, slippage and visco-elasticity are critically examined. It is argued that several factors that are usually overlooked within the framework of the most widely used simple theory can conspire to produce similar length and time scalings and morphologies. Further it is shown with examples that the precise details of the preparation conditions and materials, which also determine the initial physico-chemical roughness of the interfaces, can have profound influences in the Density Variation Induced Instability, Defect Sensitive Spinodal Regime, as well as in the True Nucleation Regime.

Journal Article↗
PubMed2004

Successful laparoscopic repair of a traumatic pubic symphysis hernia.

A 48-year-old woman presented with a hernia through the center of her pubic symphysis 6 months after conservative treatment of an open-book fracture of the pelvis. This was repaired laparoscopically with a prosthetic mesh using a transperitoneal approach. Hernia through the pubic symphysis is a rare complication after traumatic symphysis diastasis, but repair using the laparoscopic approach is feasible and associated with rapid recovery from surgery.

Athletic Injuries↗
PubMed2004

Carbon black should not be classified as a human carcinogen based on rodent bioassay data.

Numerous epidemiology studies have failed to adequately demonstrate an increased risk of lung cancer due to occupational exposure to carbon black (CB). CB is not carcinogenic to mice (oral, skin or inhalation), hamsters (inhalation or intratracheal), guinea pigs (inhalation), rabbits (skin or inhalation), primates (skin or inhalation) or rats (oral). Only studies conducted by inhalation and intratracheal administration in rats have shown significant increases in benign and malignant lung tumors and lesions described as benign cystic keratinizing squamous-cell (KSC) tumors. CB-induced lung tumor formation, including KSC lesions, occurs only in rats. An expert panel reviewing KSC lesions (induced in rats by TiO2 or p-aramid) concluded that KSC lesions are not seen in humans. Lung tumors in humans are primarily located in the bronchial airways, whereas in the rat they occur in the parenchyma and are alveolar in origin. This species-specific response (tumor formation and KSC lesions) by the rat to CB, not seen in any other laboratory species and which has not been reported in humans, strongly suggests that the results of the rat inhalation bioassay should not be considered directly relevant when assessing human risk. Therefore, CB should not be classified as carcinogenic to humans based on the rodent bioassay data.

Anatomy, Comparative↗
PubMed2004

Tocolytic therapy in conservative management of symptomatic placenta previa.

OBJECTIVES: To study the effect of ritodrine therapy on maternal and perinatal outcome in cases of symptomatic placenta previa being managed conservatively. METHODS: A prospective, randomized controlled clinical trial was made of a total of 60 women whose pregnancies ranged from 28 through 34 menstrual weeks who were randomly allocated to the two study groups using Tippet's random number table. Of these women, 30 were included in the study group where tocolysis with ritodrine was given whereas the other 30 in the control group did not receive tocolysis. Prolongation of pregnancy and birth weight of the newborn were evaluated. The unpaired t-test and chi-square test were used for statistical analysis. RESULTS: Use of tocolysis in symptomatic placenta previa was associated with significant prolongation of pregnancy (25.33 vs. 14.47 days, P<0.05) and difference in birth weight (2270 g vs. 1950 g, P<0.05). There was no observed statistical difference between the two groups with regard to number of episodes of hemorrhage after admission, total amount of blood loss during stay in hospital, number of blood transfusions and maternal complications due to tocolysis in the study group. CONCLUSIONS: The present prospective study suggests that ritodrine hydrochloride in patients with symptomatic placenta previa tends to prolong the pregnancy and result in an increase in birth weight of the babies without causing any adverse effect on the mother and fetus.

Adult↗
PubMed2004

Comparison of the analgesic efficacy and plasma concentrations of high-dose intra-articular and intramuscular morphine for knee arthroscopy.

BACKGROUND AND OBJECTIVE: It is important to provide good postoperative analgesia after discharge from day case surgery. The usefulness of intra-articular morphine for analgesia after day case knee arthroscopy remains controversial. A large dose of morphine intra-articularly may provide a good long-lasting analgesia, but its efficacy and pharmacokinetics are not known and may be no better than intramuscular morphine. We compared the effect of 10 mg intra-articular and intramuscular morphine for 24 h post-injection in a randomized double-blind study. METHODS: Forty adults undergoing knee arthroscopy were recruited and received either 10mg morphine intra-articularly or intramuscularly. Our primary outcome was overall visual analogue assessment of pain (0-100 mm scale where 0 is no pain and 100 is worst possible pain) between 4 h (on discharge) and 24 h (post-operatively). Plasma morphine concentrations were measured at 15 min, and 1, 2, 4 and 24 h. The use of additional analgesia was noted. RESULTS: The assessment of pain experienced between discharge (4 h) and 24 h was significantly better in the intra-articular (n = 20; mean+/-SD: 18+/-19) than the intramuscular (n = 19; mean+/-SD: 34+/-20) group (P = 0.027). The number of patients consuming any additional analgesia between discharge and 24 h was significantly lower in the intra-articular morphine group (P = 0.038), with 4 (20%) patients in the intra-articular group and 11 (60%) patients in the intramuscular group consuming supplementary analgesia. There were no differences in plasma morphine concentrations between the groups. CONCLUSIONS: A large dose of intra-articular morphine provided better analgesia than the same dose of intramuscular morphine, low plasma morphine levels suggesting a peripheral mechanism.

Adult↗
PubMed2004

Endoscopic visualisation to aid deep anterior lamellar keratoplasty.

AIMS: The aim of this study was to assess the value of endoscopy during deep anterior lamellar keratoplasty (DALK) by visualising the posterior cornea. This allows the surgeon to determine whether air injection had succeeded in stripping Descemet's membrane and endothelium from the posterior corneal stroma. METHODS: Four whole globes for research were obtained from the Florida eye bank with consent. A 2 mm incision was placed at the limbus and the endoscope was introduced through this into the anterior chamber. A 26-gauge needle was introduced into the cornea with the bevel positioned as deep as possible and air injected into the corneal stroma. Air was injected until the whole cornea became opaque and repeated air injections were made even after an opaque cornea was noted. The endoscopic camera was used to visualise the posterior corneal surface during this procedure. RESULTS: The view of the posterior corneal surface was clear and introduction of the probe did not interfere with the air dissection. In all four eyes, despite ease of air injection and diffuse corneal air infiltration, no large air bubble dissection of Descemet's membrane from adjacent stroma occurred. Instead multiple blistering of the posterior corneal surface could be seen. CONCLUSIONS: Endoscopy provides an effective tool to visualise the posterior corneal surface during DALK, using air dissection. This technique may become a standard adjunctive procedure during DALK.

Air↗
PubMed2004

Activation of methionine synthase by insulin-like growth factor-1 and dopamine: a target for neurodevelopmental toxins and thimerosal.

Methylation events play a critical role in the ability of growth factors to promote normal development. Neurodevelopmental toxins, such as ethanol and heavy metals, interrupt growth factor signaling, raising the possibility that they might exert adverse effects on methylation. We found that insulin-like growth factor-1 (IGF-1)- and dopamine-stimulated methionine synthase (MS) activity and folate-dependent methylation of phospholipids in SH-SY5Y human neuroblastoma cells, via a PI3-kinase- and MAP-kinase-dependent mechanism. The stimulation of this pathway increased DNA methylation, while its inhibition increased methylation-sensitive gene expression. Ethanol potently interfered with IGF-1 activation of MS and blocked its effect on DNA methylation, whereas it did not inhibit the effects of dopamine. Metal ions potently affected IGF-1 and dopamine-stimulated MS activity, as well as folate-dependent phospholipid methylation: Cu(2+) promoted enzyme activity and methylation, while Cu(+), Pb(2+), Hg(2+) and Al(3+) were inhibitory. The ethylmercury-containing preservative thimerosal inhibited both IGF-1- and dopamine-stimulated methylation with an IC(50) of 1 nM and eliminated MS activity. Our findings outline a novel growth factor signaling pathway that regulates MS activity and thereby modulates methylation reactions, including DNA methylation. The potent inhibition of this pathway by ethanol, lead, mercury, aluminum and thimerosal suggests that it may be an important target of neurodevelopmental toxins.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗
PubMed2004

Effects of plumieride, an iridoid on spermatogenesis in male albino rats.

UNLABELLED: Oral feeding of male rats with plumieride (15 mg/rat/day) for the period of 60 days did not cause any significant change in the body weight of treated rats. However, the weights of testes, epididymides, seminal vesicle and ventral prostate were significantly reduced when compared to control values. The production of step-19 spermatids was reduced by 87.26% in plumieride treated rats. The population of preleptotene and pachytene spermatocytes were decreased by 64.26% and 55.13% respectively. Spermatogonia and sertoli cell population was also affected. Plumieride treatment resulted in an arrest of spermatogenesis without any systemic side effect. Sperm motility as well as sperm density was reduced significantly. The number of mature Leydig cells was decreased and complete suppression of fertility was observed. A significant fall in the protein and sialic acid contents of the testes, epididymides, seminal vesicle and ventral prostate as well as glycogen content of testes was also noticed. Fructose in seminal vesicle was lowered whereas testicular cholesterol was elevated. There was no significant change in RBC and WBC count, haemoglobin, haematocrit and sugar in the whole blood and total protein, cholesterol, phospholipid and triglycerides in the serum. CONCLUSION: Plumieride administration arrests spermatogenesis in male rats without noticeable side effects. For the clinical use more experiments should be carried out in a phased programme.

Administration, Oral↗
PubMed2004

Determination of triazamate in apples, peas and Brussels sprouts using high-performance liquid chromatography with tandem mass spectrometry.

A rapid method was developed to allow the analysis of triazamate and the hydrolysis product triazamate acid in apples, peas and Brussels sprouts. The procedure was based on acidified methanol extraction with quantification by liquid chromatography coupled with tandem mass spectrometry detection. The detection limit, based on the lowest calibration level, was 0.005 mg kg(-1). The method was validated at 0.05 and 0.01 mg kg(-1), and was used for screening of triazamate acid in the surveillance of apples as part of the UK pesticide monitoring programme. Calibrations were linear over the range 0.004-0.080 microg ml(-1) (equivalent to 0.005-0.11 mg kg(-1)), with a minimum correlation coefficient of 0.95. The detection response showed some matrix-dependent variation. Mean recoveries were in the range 70-108% with associated per cent coefficient of variations of less than 20%.

Brassica↗
PubMed2004

Ultrasound-assisted conversion of toxic beta-asarone into nontoxic bioactive phenylpropanoid: isoacoramone, a metabolite of Piper marginatum and Acorus tararinowii.

Ultrasound-assisted synthesis of bioactive isoacoramone (1), a metabolite of Piper marginatum and Acorus tararinowii, has been achieved by oxidation of toxic beta-asarone (2) with potassium permanganate/copper sulphate/alumina into asaronaldehyde (3) followed by treatment with ethylmagnesium iodide to provide 1-(2,4,5-trimethoxy)phenyl-1-propanol (4) which upon further oxidation with potassium permanganate/copper sulphate afforded 1 in 64% yield (overall 32%). Toxicological evaluation of 1 reveals it to be nontoxic up to 60 mg/kg b.w.

Acorus↗
PubMed2004

Novel missense mutation in the coagulation factor IX catalytic domain associated with severe haemophilia B--Factor IXDelhi.

Factor IX is a vitamin K-dependent serine protease, which exists as a zymogen in the blood. On activation to factor IXa, by factor XIa or tissue factor-factor VIIa complex, it forms tenase complex with factor VIIIa, in the presence of Ca2+. This tenase complex enzymatically converts factor X to factor Xa, thereby bringing about the coagulation cascade. Mutations in factor IX gene have been shown to cause haemophilia B, which is inherited as an X-linked recessive disorder. Herein we report a novel missense mutation at the nucleotide position 30829-T > A in the exon 8 of factor IX gene. This transversion leads to the substitution of histidine 236 to glutamine. This resulting abnormal protein has been named factor IXDelhi. Molecular modelling was performed to predict the molecular pathology of this mutation. We predict that this change in the catalytic domain may affect the surface loop that accommodates Ca2+, thereby leading to severe bleeding disorder.

Catalytic Domain↗
PubMed2004

The pp67 mRNA assay in treatment and monitoring of cytomegalovirus disease in renal transplant patients in India.

The present report describes use of nucleic acid sequence-based amplification (NASBA) technology to detect pp67 mRNA of cytomegalovirus (CMV) in transplant patients in India. In our experience, pp67 mRNA assay was an accurate, rapid, and effective diagnostic tool to detect active CMV disease in 40.7% (50/123) of symptomatic transplant cases. This assay also allowed us to monitor CMV therapy. As part of the immunosuppressive regimen mycophenolate mofetil was found to increase the risk of developing CMV disease. All positive cases with this assay were subjected to antiviral therapy, with complete remission of the disease. At our center CMV NASBA assay has become the gold standard for the diagnosis of CMV disease in transplant patients.

Antiviral Agents↗
PubMed2004

Management of primary rhegmatogenous retinal detachment with inferior breaks.

BACKGROUND: Rhegmatogenous retinal detachments (RRD) with inferior breaks are usually treated by scleral buckling (SB) or pars plana vitrectomy (PPV) or a combination of both methods. However, applying a SB during PPV may produce a risk of choroidal haemorrhage. Following a recent pilot study showing that such cases can be safely treated by PPV without SB the authors re-examined their management of RRD in which inferior breaks were present. METHODS: All patients had a detached vitreous and a complex configuration of retinal breaks. A case-control study was performed to analyse the surgical methods and results of PPV on 48 consecutive patients with RRD associated with inferior breaks and 48 age/sex matched controls who underwent PPV for RRD without inferior breaks. Exclusion criteria were giant retinal tears, retinal dialysis, trauma, proliferative vitreoretinopathy (PVR) grade B or higher, schisis detachments, and eyes that had been operated previously for RRD. A simple algorithm was followed to manage patients with inferior breaks. All patients underwent a standard three port PPV with intraocular gas tamponade without supplementary SB. Patients were asked to posture face up or right or left side down for 1 week. RESULTS: 39 of the 48 patients (81.3%) with inferior breaks were treated successfully with one operation. 41 of 48 patients (85.4%) control patients achieved primary success. The final success rate was 95.8% in both groups. There was no statistical difference between the two groups. When all the cases of RRD were analysed (including external plomb/non-drain procedures) the primary success rate was 89% and final success rate 97.5%. CONCLUSIONS: This study has shown that acceptable success rates can be achieved using PPV alone to treat RRD with inferior breaks. Complications are minimised and patients in this high risk group have an 81% chance of primary success. Pars plana vitrectomy and gas will successfully reattach the retina and a supplementary SB, to support the inferior retina, is unnecessary as the intraocular gas, and face up or, right or left side down positioning will tamponade breaks satisfactorily.

Case-Control Studies↗
PubMed2004

Presentation and outcome of rhino-orbital-cerebral mucormycosis in patients with diabetes.

AIM: To report presentation and outcome of rhino-orbital-cerebral mucormycosis (ROCM) exclusively in patients with diabetes mellitus. METHODS: Retrospective, non-comparative, interventional analysis of the medical records of 35 patients with ROCM among 22 316 patients with diabetes seen over the last 12 years. RESULTS: A cohort of 23 men and 12 women with a mean (SD) age of 47.3 (14.4) years (range 18-70 years) was studied. Five patients had type 1 diabetes mellitus, 29 had type 2 diabetes mellitus, and one had secondary diabetes. Nine patients had ROCM as the first clinical manifestation of diabetes. The mean (SD) blood glucose at presentation was 20.6 (8.3) mmol/l (range 10.0 to 53.3 mmol/l) and 17 patients had ketosis/ketoacidosis. Ophthalmic symptoms and signs were pronounced: external ophthalmoplegia (89%), proptosis (83%), visual loss (80%), chemosis (74%), and eye lid gangrene (14%). Non-ophthalmic manifestations included sinusitis (100%), nasal discharge/ulceration (74%), infranuclear VI nerve palsy (46%), palatal necrosis (29%), cerebral lobe involvement (20%), and hemiparesis (17%). Computed tomography/magnetic resonance imaging showed involvement of paranasal sinuses in all patients with ethmoid (86%) and maxillary (80%) sinuses being most frequently involved. Orbital involvement was observed in 80% of patients with cavernous sinus thrombosis in 11%, and internal carotid occlusion and hydrocephalus in 3% each. All were treated with amphotericin B (3-3.5 g) and 26 (74%) patients underwent appropriate surgery. Twenty one patients (68%) survived with a mean (SD) follow up of 39.6 (34.1) months (range 10 months to 11 years). Factors related to poor survival included delay in diagnosis and treatment (p<0.05), facial and/or eye lid gangrene (p<0.05), hemiplegia (p<0.05), cerebral invasion by mucorales (p<0.05), and treatment with amphotericin B alone (p<0.05). CONCLUSIONS: In patients with diabetes and ROCM, ROCM was the presenting manifestation in one fourth of the patients. Ophthalmic and extensive cerebral involvement predominated in the clinical picture. Delay in treatment due to late presentation and associated complications were major determinants of the survival outcome in these patients.

Adolescent↗