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Biomedical subjects

A Tyagi

Publications and source records attributed to A Tyagi.

At least 19 recordsLinked to original sources
PubMed2006

Compensator-based intensity-modulated radiotherapy in head and neck cancer: our experience in achieving dosimetric parameters and their clinical correlation.

AIMS: To review the Batra Hospital and Medical Research Centre experience of using compensator-based intensity-modulated radiotherapy (IMRT) to treat head and neck cancer. MATERIALS AND METHODS: Between October 2003 and August 2004, 18 patients underwent IMRT for head and neck cancer at our institution. IMRT was delivered using partial transmission high-resolution compensator blocks. RESULTS: With a median follow-up of 13.3 months, two patients had residual disease and two failed in the gross tumour volume (GTV). The complete response rate after surgical salvage was 94.5%. Both the locoregional relapse-free and disease-free survival rates were 81.8%. The target coverage in terms of average maximum, mean and minimum dose (in Gy) delivered was 78.6, 73.5 and 58.4 to the GTV-planning target volume, 82.3, 70.9 and 47.3 to clinical target volume 1 (CTV1) and 82.9, 66.2 and 29.6 to CTV2. The dose constraint of 30 Gy to less than 50% of the contralateral parotid volume was achieved in 12 (66.7%) patients. If the dose constraint was revised to 35 Gy, at least 50% of the parotid volume was spared in 17 (94.5%) patients. On average, 75% of the contralateral parotid volume received a dose less than 35 Gy in 13 (72.3%) patients with grade I xerostomia, whereas this was 49.3% in five (27.7%) patients with grade II xerostomia, and the difference was statistically significant (P = 0.001). CONCLUSIONS: In our initial experience, compensator-based IMRT is feasible with regard to target coverage and parotid volume sparing. The parotid volume dose has significant clinical implications on the grade of xerostomia. Our results invoke rethinking into the issues of the parotid volume dose constraint in our subpopulation.

Carcinoma, Squamous Cell↗
PubMed2006

Laryngotracheal hypoplasia--a rare cause of difficult intubation.

Generalized hypoplasia of the larynx and trachea is a very rare condition with only one case reported in the literature. A pregnant woman presented for an emergency laparotomy under general anaesthesia. Endotracheal intubation with conventional sizes of tracheal tubes failed, despite a Cormack and Lehane grade I laryngoscopic view. Subsequent investigations demonstrated generalized hypoplasia of the larynx and trachea. In this report, successful anaesthetic management of this case is discussed along with other possible options.

Adult↗
PubMed2005

Cerebral phaeohyphomycosis caused by Fonsecaea monophora.

We report a case of cerebral phaeohyphomycosis in a 53-year-old immunocompetent diabetic male, caused by Fonsecaea monophora. Computerized tomography of the brain revealed an abscess, which yielded F. monophora in pure culture. The patient's condition deteriorated on treatment with voriconazole and 5-fluorocytosine, and improved subsequently with high-dose itraconazole. The genus Fonsecaea has recently been revised and the new species F. monophora generated from molecular analysis of isolates, most of which were originally identified as Fonsecaea pedrosoi. This is the fourth case of cerebral infection known to have been caused by F. monophora, although only the first reported as such. These cases suggest that the clinical potential of F. monophora differs from that of F. pedrosoi, one of the main agents of chromoblastomycosis, with F. monophora being predominantly neurotropic in the human host.

Ascomycota↗
PubMed2005

Randomised trial of intravenous infusion of ephedrine or mephentermine for management of hypotension during spinal anaesthesia for Caesarean section.

This study compared the effects of intravenous infusions of ephedrine and mephentermine for maintenance of maternal arterial pressure and neonatal outcome in pregnant women receiving subarachnoid block for lower segment Caesarean section. Sixty patients who developed hypotension following subarachnoid block for Caesarean section were randomly divided into two groups of 30 each to receive an intravenous infusion of ephedrine or mephentermine. Hypotension was defined as a decrease in systolic blood pressure of > or = 20% from the baseline value or an absolute value of <100 mmHg, whichever was higher. The vasopressor infusion was titrated to maintain systolic blood pressure between 'hypotension' and baseline values. Baseline haemodynamic parameters, haemodynamic changes subsequent to the start of vasopressor infusion, duration of hypotension and amount of vasopressor required were statistically similar for both groups. Neonatal APGAR scores and acid-base profiles were also comparable. To conclude, mephentermine can be used as safely and effectively as ephedrine for the management of hypotension during spinal anaesthesia in patients undergoing elective Caesarean section.

Adrenergic Agents↗
PubMed2005

Expression of delta1-pyrroline-5-carboxylate synthetase gene during drought in rice (Oryza sativa L.).

The 45-days-old seedlings of drought resistant (N-22, CR143-2-2) and susceptible rice (Oryza sativa L.) genotypes (Panidhan, Pusa-169) were subjected to osmotic stress in PEG-6000 solution of -10 and -16 bar and the relative water content (RWC), proline content, and pyrroline-5-carboxylate synthetase (P5CS) activity and its P5CS expression were studied. A gradual decrease in RWC was observed in tolerant genotypes, whereas the decrease was drastic in susceptible ones. Proline content and P5CS activity increased both in susceptible and tolerant genotypes; the increase was higher in tolerant genotypes. Higher proline levels in tolerant genotypes were due to increased P5CS activity. The EcoRI, BamHI and XbaI restricted DNA of N-22 and Panidhan genotypes were hybridized with Arabidopsis P5CS sequence and a single band (approx 2.4 kb) was observed, however, P5CS expression was more in N-22 as compared to Panidhan.

1-Pyrroline-5-Carboxylate Dehydrogenase↗
PubMed2004

MIB1 proliferation index in meningiomas: does it predict recurrence? A clinicopathological study.

The usefulness of proliferation marker MIB1 in predicting recurrences in cranial meningiomas when other clinical and pathological factors are considered was assessed. Data from 65 patients with meningiomas were analysed and their clinical notes reviewed to define the Simpson grade of surgical excision, the location of tumour, amongst other clinical factors. The diagnosis was reviewed; immunohistochemical staining for a proliferation marker MIB1 was carried out on archival formalin-fixed, paraffin-embedded tumour and a labelling index for MIB1 (MIB1 L1) calculated. Analysis was undertaken of the impact of histology, grade of excision, tumour location and proliferation index on the risk of recurrence. The grade of surgical resection and histology type were the most important factors likely to predict recurrence. MIB1 LI was not considered useful in predicting tumour recurrence.

Adult↗
PubMed2004

Rate-dependent left bundle branch block during anaesthesia.

Rate-dependent left bundle branch block during general anaesthesia is rare. Its occurrence makes electrocardiographic diagnosis of acute myocardial ischaemia or infarction difficult. It can also be confused with a slow rate ventricular tachycardia. We present a case of rate-dependent left bundle branch block in a patient with no previous history of ischaemic heart disease. Carotid sinus massage resulted in a decrease in heart rate and reversion to normal sinus rhythm.

Anesthesia, General↗
PubMed2003

Filters in anaesthesia and intensive care.

The use of various types of filters in anaesthesia and intensive care seems ubiquitous, yet authentication of the practice is scarce and controversies abound. This review examines evidence for the practice of using filters with blood and blood product transfusion (standard blood filter, microfilter, leucocyte depletion filter), infusion of fluids, breathing systems, epidural catheters, and at less common sites such as with Entonox inhalation in non-intubated patients, forced air convection warmers, and air-conditioning systems. For most filters, the literature failed to support routine usage, despite this seemingly being popular and innocuous. The controversies, as well as guidelines if available, for each type of filter, are discussed. The review aims to rationalize the place of various filters in the anaesthesia and intensive care environment.

Anesthesiology↗
PubMed2002

Central neuraxial blocks and anticoagulation: a review of current trends.

Patients receiving anticoagulants offer a challenge to anaesthesiologists. The issue of spinal haematoma following central neuraxial block in such patients is a contentious issue. Although rare, with an estimated incidence of < 1:150,000 for epidural blocks and 1:220,000 for spinal anaesthetics in patients with normal coagulation status, this is an emergency situation with a potentially grave prognosis. The review presents cases of spinal haematomata that have occurred in the last 5 years, both spontaneously and after central neuraxial blockade. Of the 60 cases reported in the literature, 33% occurred following central neuraxial block and, of these, 55% were associated with concomitant use of anticoagulants. The pharmacology of the newer and older anticoagulants is also described. The variety of risk factors and diverse recommendations that have been described in these patients are reviewed.

Anesthesia, Spinal↗
PubMed2002

Comparison of isoprenaline with adrenaline as components of epidural test dose solutions for halothane anaesthetized children.

In this randomized controlled trial we studied the haemodynamic effects of intravenous injection of lignocaine 1 mg/kg with either no additive, isoprenaline 0. 05 microg or 0.075 microg/kg, or adrenaline 0.5 microg/kg in children anaesthetized with halothane. An increase of > or = 10 bpm in heart rate or > or = 20% rise in blood pressure was taken as a positive test response. Adrenaline was confirmed to be an unreliable marker with a positive test in only 67% of cases. For both doses of isoprenaline, the heart rate changes produced a positive test in 100% of cases. There was no statistically significant difference between the two doses of isoprenaline in regard to mean maximum increase in heart rate, mean time of beginning, ending or duration of positive test response and mean time to reach peak heart rate. The positive test response began between 10 and 50 seconds and lastedfor an average of 69 +/- 54 seconds with the lower dose of isoprenaline 0.05 microg/kg No advantage could be seen with the higher dose of isoprenaline. Change in blood pressure was not a useful criterion to detect intravascular injection. Recommendations for the use of isoprenaline as a marker of intravascular injection during regional blockade must be deferred until the safety of this agent's effect on neurological tissue is confirmed.

Analysis of Variance↗
PubMed2002

Respiratory failure in acute intermittent porphyria.

We report two patients of acute intermittent porphyria (AIP) who presented with acute respiratory failure. Only one such previous report could be found. Occasionally, neuropathy may be the presenting feature in AIP which may progress to respiratory embarrassment. The cause of this neuropathy has been hypothesized to be direct neurotoxicity of delta-ALA by interaction with GABA receptor, altered tryptophan metabolism and may be heme depletion in nerve cells.

Adult↗