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Biomedical subjects

A Pathak

Publications and source records attributed to A Pathak.

At least 37 records · Page 2Linked to original sources
PubMed2004

An evaluation of sealing ability of endodontic materials as root canal sealers.

An in vitro dye leakage study was carried out to compare the apical microleakage of vitapex (calcium hydroxide based paste) when used with single gutta percha cone with that of dentalis KEZ (calcium hydroxide and zincoxide eugenol based sealer) and zincoxide-eugenol sealer when used with laterally condensed gutta percha obturation technique. One hundred single rooted human anterior teeth were instrumented and randomly divided into three experimental groups of 30 teeth each and two control groups of 5 teeth each. Teeth in the first group were obturated using a single master gutta percha cone and vitapex as root canal sealer and those of second group were obturated with laterally condensed gutta percha using dentalis KEZ as sealer. Third experimental group was filled with laterally condensed gutta-percha using zinc-oxide eugenol as sealer. Teeth were then suspended in 2% methylene blue. After this, teeth were demineralized dehydrated and cleared. Linear dye penetration was determined under stereomicroscope (x10) with calibrated eye piece. Results of this study showed that calcium hydroxide based endodontic material leaked comparatively less as compared to zinc oxide Eugenol sealer. Vitapex with single gutta-percha cone provided an adequate apical Seal against dye penetration.

Calcium Hydroxide↗
PubMed2004

Possible relationship between phenylthiocarbamide taste sensitivity and epilepsy.

The study was based on the data of a sample of 400 epileptic patients (200 idiopathic and 200 symptomatic) and 100 normal healthy individuals serving as controls. The PTC threshold distribution was bimodal. The number of non-tasters among idiopathic epileptics (35.5%) and symptomatic epileptics (32.5%) was significantly higher than controls (20%). The relative incidence of non-tasters in idiopathic and symptomatic epilepsies was 2.20 and 1.93 respectively. There is evidence that non-tasters tend to ingest a greater quantity of bitter tasting goitrogenic substances present naturally in edible plants which in turn exert greater thyroid stress in non-tasters or less sensitive tasters. Such a stress during intrauterine or early childhood growth and development might have affected neurological maturation which in turn made them more susceptible to epilepsy than tasters, who faced lesser stress.

Adolescent↗
PubMed2004

A clinical assessment of the effectiveness of mouthwashes in comparison to toothbrushing in children.

The study compared the efficacy of unsupervised tooth-brushing done once a day before breakfast (phase 1), with twice daily mouthrinsing with the three different commercially available mouthwashes containing 0.2% sodium fluoride (phase 2), a combination of 0.03% triclosan and 0.05% sodium fluoride (phase 3), and 0.2% chlorhexidine (phase 4) in 20 children aged 13-14 year, in reducing dental plaque formation. The results showed that there was a statistically significant difference in plaque reduction between phases 1 & 2; 1 & 3; 2 & 4 and 3 & 4. The mandibular arch harboured more plaque than the maxillary arch in phase 1 (p<0.05). Irrespective of the mouthwash used, the lingual/palatal surfaces had less plaque than the facial surfaces (p<0.05). The mean cumulative plaque scores of the mandibular lingual surfaces was more in comparison to the maxillary palatal surfaces in phases 1, 2 and 3 (p<0.05). It was therefore, concluded that 0.2% chlorhexidine was comparable to tooth brushing done once a day, before breakfast.

Adolescent↗
PubMed2004

Energy cost and cardiorespiratory changes during the practice of Surya Namaskar.

Surya Namaskar (SN), a group of Yogic exercise consists of a set of twelve postures which is practiced by some of the yoga practitioners. The present study was undertaken to observe critically the energy cost and different cardiorespiratory changes during the practice of SN. Twenty-one male volunteers from the Indian Army practiced selected Yogic exercises for six days in a week for three months duration. The Yogic practice schedule consisted of Hatha Yogic Asanas (28 min), Pranayama (10.5 min) and Meditation (5 min). In the Yogic practice schedule 1st they practiced Kapal Bhathi (breathing maneuvers) for 2 min then Yogamudra (yogic postural exercise) for 2 min, after that they took rest until oxygen consumption and heart rate (HR) came to resting value. Subsequently subjects performed SN for 3 min 40 seconds on an average. After three months of training at the beginning of the fourth month subjects performed entire Yogic practice schedule in the laboratory as they practiced during their training session and experiments were carried out. Their pulmonary ventilation, carbondioxide output, Oxygen consumption, HR and other cardiorespiratory parameters were measured during the actual practice of SN. Oxygen consumption was highest in the eighth posture (1.22+/-0.073 1 min(-1)) and lowest in the first posture (0.35+/-0.02 1 min(-1)). Total energy cost throughout the practice of SN was 13.91 kcal and at an average of 3.79 kcal/min. During its practice highest HR was 101+/-13.5 b.p.m. As an aerobic exercise SN seemed to be ideal as it involves both static stretching and slow dynamic component of exercise with optimal stress on the cardiorespiratory system.

Adult↗
PubMed2003

Alphavbeta3-integrin antagonists inhibit thrombin-induced proliferation and focal adhesion formation in smooth muscle cells.

Alphavbeta3-integrin antagonists reduced neointimal formation following vascular injury in eight different animal models. Because alpha-thrombin contributes to neointimal formation, we examined the hypothesis that alphavbeta3-integrins influence alpha-thrombin-induced signaling. Cultured rat aortic smooth muscle cells (RASMC) expressed alphavbeta3-integrins as demonstrated by immunofluorescence microscopy and fluorescence-activated cell sorting analysis. Proliferative responses to alpha-thrombin were partially inhibited by anti-beta3-integrin monoclonal antibody F11 and by cyclic RGD peptides. Immunofluorescence microscopy showed that alpha-thrombin stimulated a rapid increase in the formation of focal adhesions as identified by vinculin staining and that this effect was partially inhibited by alphavbeta3 antagonists. Beta3-integrin staining was diffuse in quiescent RASMC and did not concentrate at sites of focal adhesions following thrombin treatment. Alpha-thrombin elicited a time-dependent increase in activation of c-Jun NH2-terminal kinase-1 (JNK1) and in tyrosine phosphorylation of focal adhesion kinase (FAK). Alphavbeta3-integrin antagonists partially inhibited increases in JNK1 activity but had no effect on FAK phosphorylation. In SMC isolated from beta3-integrin-deficient mice, focal adhesion formation was impaired in response to thrombin but not sphingosine-1-phosphate, a potent activator of Rho. In summary, alphavbeta3-integrins play an important role in alpha-thrombin-induced proliferation and focal adhesion formation in RASMC.

Animals↗
PubMed2003

Intermittent low dose intrathecal sodium nitroprusside therapy for treatment of symptomatic aneurysmal SAH-induced vasospasm.

Eight patients with aneurysmal subarachnoid haemorrhage (SAH) received intrathecal sodium nitroprusside therapy (ITSNPT) in the form of intermittent bolus doses for delayed cerebral vasospasm after undergoing clipping of an aneurysm. Five patients were administered ITSNPT to combat refractory symptomatic vasospasm while three patients received prophylactic ITSNPT in view of the possibility of imminent clinical vasospasm. In five patients the therapy was instituted through the intraventricular route, while in three the drug was instilled into the basal cistern. Sodium nitroprusside (SNP) was administered at an interval of 3-12 h, in varying bolus doses ranging between 2 and 5 mg depending upon the (i) mean flow velocity values on transcranial Doppler study and (ii) clinical response. The end point of ITSNPT was either relief of vasospasm, any adverse effect or contraindication to continuation of ITSNPT. All except one patient survived. One patient had mild residual neurological deficit following an infarct. All the three patients who received prophylactic ITSNPT had good outcomes.

Adult↗
PubMed2003

Effects of vitamin E supplementation during erythropoietin treatment of the anaemia of prematurity.

AIMS: To evaluate the effects of vitamin E supplementation on haemoglobin concentration and the requirement for transfusion in premature infants treated with erythropoietin and iron. METHODS: Randomised, double blind, placebo controlled trial. Thirty infants </=32 weeks gestation and </=1250 g birth weight, who were defined as stable based on minimal requirements for respiratory support and phlebotomy, and absence of major congenital anomalies were enrolled. All were treated with erythropoietin and iron, and were randomised to receive, in addition, either vitamin E 50 IU/day or placebo for eight weeks or until discharge, whichever came first. RESULTS: Despite higher vitamin E (alpha-tocopherol) levels in the experimental group in weeks 3 (49.0 v 28.1 micro mol/l) and 8 (66.2 v 38.5 micro mol/l), there were no differences in haemoglobin, reticulocyte count, iron concentration, or transfusion requirement. CONCLUSIONS: Oral vitamin E supplementation at 50 IU/day does not increase the response of preterm infants to erythropoietin and iron. Vitamin E obtained through standard nutrition may have been sufficient or higher doses may be required.

Anemia, Neonatal↗
PubMed2003

Intraventricular sodium nitroprusside therapy: a future promise for refractory subarachnoid hemorrhage-induced vasospasm.

A prospective study was carried out to evaluate the efficacy of intraventricular sodium nitroprousside (SNP) in the reversal of refractory vasospasm secondary to aneurysmal subarachnoid hemorrhage (SAH). Ten patients of aneurysmal SAH with symptomatic vasospasm, corroborated on Transcranial Doppler (TCD) and/or angiography, were included in the study. The mean age distribution of the patients was 50.8 years (range 33-65 years) with an equal number of males and females. Once vasospasm was refractory even after 12 hours of SAH therapy, intraventricular SNP was instilled in an escalating dose and the reversal of vasospasm was monitored on TCD and/or angiography. All patients showed improvement in TCD velocity on day 0 through day 3. Partial to complete reversal of vasospasm was demonstrated on angiography in all the patients, though not in all the vessels. Two patients who had weakness of limbs due to vasospasm improved following intraventricular SNP therapy. Vomiting was the commonest adverse effect (7/10). Three patients had mild fluctuation in blood pressure. The overall outcome was good in 6 out of 10 patients. The study suggests that intraventricular SNP therapy is effective in reversing the changes even in established cases of SAH-induced vasospasm.

Adult↗
PubMed2003

Local control of high-grade gliomas with limited volume irradiation versus whole brain irradiation.

INTRODUCTION: To evaluate the role of limited field radiation therapy in the management of high-grade gliomas and glioblastoma multiforme (GBM). MATERIAL AND METHODS: From July '96 to January '98, 50 newly diagnosed patients of high-grade gliomas (Grade III and IV) and glioblastoma multiforme who underwent surgery in the form of partial, sub-total or near-total excision as the primary treatment were enrolled in this study. The patients were randomized to receive two different postoperative external radiation protocols, Study Group A: Localized field external radiotherapy 50 Gy/25#/5 wks followed by Boost 10 Gy/5#/1 wk, Control Group B: Whole brain external radiotherapy 40 Gy/20#/4 wks followed by Boost 20 Gy/10#/2 wks by localized field. RESULTS: 20/25 (80%) patients in the study group and 14/25 (56%) patients in the control group showed improvement in their Karnofsky Performance Status (KPS). Thus a significant difference in the performance status was noted in favor of limited field irradiation. No significant difference in the local response was seen between the two groups after radiotherapy. Six months progression-free survival of the study group was 44% as compared to 26% in the control group. Six months overall survival was 66.67% in the study group and 50.72% in the control group (P<0.01). Maximum recurrences were noticed within 2 cm of the original tumor margin in both the groups. CONCLUSIONS: Although local control and survival of the patient in both the groups were same, performance status definitely improved in patients treated with localized field irradiation only.

Brain Neoplasms↗
PubMed2002

Solid-phase synthesis and bioevaluation of lupeol-based libraries as antimalarial agents.

The use of the triterpenoid lupeol as a scaffold for the synthesis of lupeol-based libraries is described. Lupeol was anchored to a solid support (Rink amide/Sieber Amide) through aliphatic dicarboxylic acid moieties, which also served as a site for introducing diversity. The resulting polymer linked 3beta-O (resin-alkanoyl)-lup-20(29)-ene 3 was used to generate key intermediates 3beta-O (resin-alkanoyl)-30-bromo-lup-20(29)-ene 4 and 3beta-O (resin-alkanoyl)-30-amino-lup-20(29)-ene 6 for the generation of libraries based on disubstituted lupeol derivatives. A 96-member library was screened for its in-vitro antimalarial activity against Plasmodium falciparum.

Animals↗
PubMed2002

[Holter EKG for the hypertensive heart disease].

During chronic mechanical overload induced by hypertension, left ventricular hypertrophy predisposes to atrial and ventricular arrhythmias. Atrial arrhythmias, mainly atrial fibrillation, decrease cardiac output and increase the risk of embolism whereas ventricular arrhythmias remain the major cause of sudden death. In hypertensive patients, Holter EKG recordings frequently detect atrial or ventricular premature beats and more rarely atrial or ventricular tachycardia. In these patients, the presence of non-sustained ventricular tachycardia is considered as an independent predictor of mortality. Moreover, this non invasive method through the assessment of heart rate variability allows the study of the autonomic control of the heart, known to modulate occurrence of arrhythmias.

Atrial Fibrillation↗
PubMed2002

The Willgerodt-Kindler reaction on lupenone: unusual oxidative dimerization.

In continuation of our interest in chemical modification of triterpenoids, the Willgerodt-Kindler reaction of a lupane type triterpenoid lupenone provided a novel dimerized product 2. Formation of 2 is associated with an unusual oxidative dimerization of lupenone under Willgerodt-Kindler reaction conditions. The structure 2 was confirmed by extensive analysis of spectroscopic data including ES-MS and 2D-NMR.

Dimerization↗
PubMed2002

Synthesis of combinatorial libraries based on terpenoid scaffolds.

Triterpenoid-based scaffolds betulinic acid (1a) and ursolic acid (1b), have been used for the generation of combinatorial libraries in parallel format using solid phase organic synthesis method. These templates have the potential for the synthesis and amplification of triterpenoid-based compounds with one and two-point diversity. This has been demonstrated by the synthesis of two small libraries comprising 18 derivatives each of betulinic acid and ursolic acid with structural diversity at C-3 and C-28 positions. The primary screening of antimalarial activity of these libraries against P. falciparum in vitro led to the identification of four compounds with 5 fold increase in the activity compared to betulinic and ursolic acids.

Animals↗
PubMed2002

[Effects of bradykinin in the cardiovascular effects of angiotensin-converting enzyme inhibitors].

The role of bradykinin in the cardiovascular effects of angiotensin converting enzyme inhibitors remains difficult to establish. On their haemodynamic effects, bradykinin acts during their acute administration, participating in their vasodilatation action, while during their chronic administration they act slightly or not at all. On their trophic effects, the action of the tissue kallikrein-kinin system, suggested by the results of animal experimentation, is yet to be demonstrated in man. For their effects on cardiovascular morbidity and mortality the role of bradykinin remains under discussion. Nevertheless, besides ACE inhibitors, the other therapeutic agents which increase the levels of bradykinin, such as neutral endopeptidase inhibitors, have a significant field of development in the course of cardiovascular pathologies.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2002

Primary central nervous system lymphoma: experience of 46 cases with review of literature.

Primary central nervous system lymphomas (PCNSL) constitutes only 1.0 to 1.5% of all brain tumors. Their incidence has gone up over tenfold in the last 25 years. Though, there has been an association of PCNSL with acquired immune deficiency syndrome (AIDS), yet the increased incidence of PCNSL appears to be real and unrelated to AIDS and organ transplantation. This increased incidence could be because of improvement in diagnostic technology and practice. The outcome remains gloomy despite surgical resection, radiotherapy and intensive adjuvant chemotherapy regimens, as majority of the patients succumb to the disease, with only 30-40% survival in patients under 70 years of age.

Adolescent↗
PubMed2001

Combination angiostatin and endostatin gene transfer induces synergistic antiangiogenic activity in vitro and antitumor efficacy in leukemia and solid tumors in mice.

Angiostatin and endostatin are potent endothelial cell growth inhibitors that have been shown to inhibit angiogenesis in vivo and tumor growth in mice. However, tumor shrinkage requires chronic delivery of large doses of these proteins. Here we report synergistic antitumor activity and survival of animals when these factors are delivered in combination to tumors by retroviral gene transfer. We have demonstrated this efficacy in both murine leukemia and melanoma models. Complete loss of tumorigenicity was seen in 40% of the animals receiving tumors transduced by the combination of angiostatin and endostatin in the leukemia model. The synergy was also demonstrated in vitro on human umbilical vein endothelial cell differentiation and this antiangiogenic activity may suggest a mechanism for the antitumor activity in vivo. These findings imply separate pathways by which angiostatin and endostatin mediate their antiangiogenic effects. Together, these data suggest that a combination of antiangiogenic factors delivered by retroviral gene transfer may produce synergistic antitumor effects in both leukemia and solid tumors, thus avoiding long-term administration of recombinant proteins. The data also suggest that novel combinations of antiangiogenic factors delivered into tumors require further investigation as therapeutic modalities.

Angiogenesis Inhibitors↗