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Biomedical subjects

A Chaturvedi

Publications and source records attributed to A Chaturvedi.

At least 19 recordsLinked to original sources
PubMed2006

Recurrence rates after DCE-MRI image guided planning for breast-conserving surgery following neoadjuvant chemotherapy for locally advanced breast cancer patients.

BACKGROUND: Neoadjuvant therapy results in a significant increase in breast-conserving surgery. However, traditional imaging methods are unable to accurately predict the extent of viable residual disease leading to uncertainty in surgical planning and some previous studies have shown a disproportionately high incidence of locoregional recurrence. Dynamic contrast enhanced-MRI (DCE-MRI) has been shown to provide a potentially more accurate prediction of residual disease. RESULTS: Patients undergoing neoadjuvant chemotherapy for breast cancer in our unit are staged with the DCE-MRI of the breast performed at 1.5 T before, during and after treatment and the final result was used to plan surgery. Two hundred and four patients with breast cancer were treated with neoadjuvant chemotherapy between 1996 and April 2005. Eighteen of these patients had distant metastases at the time of initial diagnosis and so were excluded from the present study. Following neoadjuvant chemotherapy, 186 patients underwent surgical treatment. Of these, 68 patients had breast-conserving surgery. At a median follow up of 30 months (range: 5.6-72 months) 21 patients in this group developed subsequent recurrence (21/68 - 30%) of whom 9 (9/68 - 13%) had locoregional recurrence, 7 had local recurrence (7/68 - 10%), and 17 (17/68 - 25%) had distant recurrence. Logistic regression analysis revealed only vascular invasion (p=0.006) of the tumour to be significantly associated with overall recurrence. None of the pathological factors (ER, PR status, vascular invasion, lymph node metastases, pathological complete response to neoadjuvant chemotherapy) showed a significant association with locoregional recurrence. CONCLUSION: Breast-conserving surgery with DCE-MRI planning after neoadjuvant chemotherapy provides an acceptable level of local recurrence without the need for mastectomy.

Adult↗
PubMed2006

Molecular simulations of the pressure, temperature, and chemical potential dependencies of clay swelling.

A new method for the determination of clay swelling thermodynamics from computer simulation is discussed and evaluated. This method allows for the determination of temperature, pressure, and water chemical potential dependence of clay swelling from simulations at a single thermodynamic state point. The temperature dependence and pressure dependence of clay swelling are shown to be directly related to the composite system entropy and volume change, respectively, that accompany swelling. Expressions for the chemical potential dependence of clay swelling are used to determine constant pressure layer spacing and adsorption isotherms, quantities that are well suited for comparison with experimental measurements. This method is evaluated through grand isoshear ensemble simulations of Na-montmorillonite, a prototypical swelling clay. Approximations associated with all expressions are discussed with explicit calculations used to demonstrate their regimes of validity.

Journal Article↗
PubMed2006

Lidocaine infiltration of the scalp does not completely abolish increased intraocular pressure due to skull pin insertion.

Insertion of skull pins results in haemodynamic perturbations, which can be blunted by local anaesthetic infiltration of the pin sites. No study has assessed the effects on intraocular pressure. General anaesthesia was induced in 71 patients undergoing cervical spine surgery with attachment of Gardner Wells tongs to the skull. Skull pins were attached five minutes after induction following either saline (group I, 35 patients) or lidocaine (group II, 36 patients) infiltration of scalp. Intraocular pressure, mean arterial pressure and heart rate were recorded before (baseline), immediately after, and 60 s following pin insertion and analysed statistically. Insertion of pins increased intraocular pressure in both groups (from 8.4+/-2.7 to 14.2+/-3.0 mmHg in group I, and from 8.8+/-2.3 to 12.7+/-2.7 mmHg in group II, P < 0.001), which persisted even at 60 s but the increase was significantly greater in group I. Insertion of pins significantly increased blood pressure in group I only. We conclude that lidocaine infiltration at the skull pin sites for Gardner Wells tong attachment fails to completely abolish increased intraocular pressure.

Adult↗
PubMed2006

Neoadjuvant chemotherapy in breast cancer: early response prediction with quantitative MR imaging and spectroscopy.

A prospective study was undertaken in women undergoing neoadjuvant chemotherapy for locally advanced breast cancer in order to determine the ability of quantitative magnetic resonance imaging (MRI) and proton spectroscopy (MRS) to predict ultimate tumour response (percentage decrease in volume) or to detect early response. Magnetic resonance imaging and MRS were carried out before treatment and after the second of six treatment cycles. Pharmacokinetic parameters were derived from T1-weighted dynamic contrast-enhanced MRI, water apparent diffusion coefficient (ADC) was measured, and tissue water:fat peak area ratios and water T2 were measured using unsuppressed one-dimensional proton spectroscopic imaging (30 and 135 ms echo times). Pharmacokinetic parameters and ADC did not detect early response; however, early changes in water:fat ratios and water T2 (after cycle two) demonstrated substantial prognostic efficacy. Larger decreases in water T2 accurately predicted final volume response in 69% of cases (11/16) while maintaining 100% specificity and positive predictive value. Small/absent decreases in water:fat ratios accurately predicted final volume non-response in 50% of cases (3/6) while maintaining 100% sensitivity and negative predictive value. This level of accuracy might permit clinical application where early, accurate prediction of non-response would permit an early change to second-line treatment, thus sparing patients unnecessary toxicity, psychological morbidity and delay of initiation of effective treatment.

Adult↗
PubMed2006

Atypical presentations in Chiari II malformation.

Myelomeningocele with Chiari II malformation and hydrocephalus is a common association seen in infants with a congenital failure of neurulation. Here we report two cases of such an association presenting with different sets of problems. The first patient presented with severe inspiratory stridor due to bilateral abductor vocal cord paralysis, which was relieved completely within 24 h of definitive surgery. The second patient experienced intraoperative cardiac arrest. Definitive surgery was followed after successful cardiopulmonary resuscitation. The cause of the perioperative sequence of events in both cases is attributed to the associated pathologies of Chiari II malformation.

Arnold-Chiari Malformation↗
PubMed2005

Effects of stellate ganglion block on cerebral haemodynamics as assessed by transcranial Doppler ultrasonography.

BACKGROUND: Stellate ganglion block (SGB) causes vasodilatation in the skin of the head and neck because of regional sympathetic block. Its effects on cerebral haemodynamics, in health or in disease, are not clear. We evaluated the effects of SGB on ipsilateral middle cerebral artery flow velocity (MCAFV), estimated cerebral perfusion pressure (eCPP), zero flow pressure (ZFP), carbon dioxide reactivity (CO2R) and cerebral autoregulation using transcranial Doppler ultrasonography (TCD). METHODS: Twenty male patients, with pre-existing brachial plexus injury, and undergoing SGB for the treatment of complex regional pain syndrome of the upper limb, were studied. For SGB, 10 ml of plain lidocaine 2% was used and the onset of block was confirmed by presence of ipsilateral Horner's syndrome. The MCAFV, eCPP, ZFP, CO2R, and cerebral autoregulation were assessed before and after SGB using established TCD methods. The changes in these variables were analysed using Wilcoxon's signed rank test. RESULTS: The block caused a significant decrease in MCAFV from median (inter-quartile range) value of 61 (53, 67) to 55 (46, 60) cm s(-1), a significant increase in eCPP from 59 (51, 67) to 70 (60, 78) mm Hg, and a significant decrease in ZFP from 32 (26, 39) to 25 (16, 30) mm Hg. There were no significant changes in CO2R or cerebral autoregulation. CONCLUSION: The increase in eCPP, decrease in ZFP, and no changes in CO2R or cerebral autoregulation suggest that the SGB decreases cerebral vascular tone without affecting the capacity of the vessels to autoregulate. These effects may be of therapeutic advantage in relieving cerebral vasospasm in certain clinical settings.

Adolescent↗
PubMed2005

Rupture of aorta and inferior vena cava during lumbar disc surgery.

Major vascular injury during lumbar disc surgery has been recognized as an unusual but well described complication. A potentially fatal outcome can be avoided by a high index of suspicion and an early diagnosis. We present a rare case of aortic and inferior vena caval injury in a 50-year-old female patient undergoing intervertebral disc surgery at lumbar one and two levels. A quick diagnosis and prompt management resulted in a favourable outcome for the patient.

Aorta, Abdominal↗
PubMed2005

MRI and conservative treatment of locally advanced breast cancer.

AIMS: The objectives of this study were to compare the efficacy of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in assessing the response of primary breast carcinoma to neoadjuvant chemotherapy compared to conventional imaging modalities, and to see how surgical outcome was influenced as a result of these findings. METHODS: Thirty-four patients with locally advanced primary breast cancer underwent conventional imaging and DCE-MRI following six cycles of neoadjuvant chemotherapy prior to surgery. Changes in surgical management based on the post-chemotherapy DCE-MRI findings were recorded. RESULTS: Prior to neoadjuvant chemotherapy, 22 of the 34 patients were assessed as requiring mastectomy and the remaining 12 were considered inoperable. Following chemotherapy two patients were still considered inoperable. In 11 of the 34 patients, the final decision to proceed to either mastectomy or non-surgical management was based primarily on pre-treatment disease status or patient choice. DCE-MRI findings, therefore, contributed to the operative decision in 21 of 34 patients. Two of these 21 patients were spared surgery as DCE-MRI demonstrated complete response to chemotherapy and one declined surgery. The remaining 18 were able to undergo wide local excision, with only two patients subsequently requiring mastectomy for involved margins. CONCLUSIONS: DCE-MRI is able to accurately predict those patients suitable for breast conserving surgery following neoadjuvant chemotherapy and should be the imaging modality of choice in assessing the response of patients with primary breast carcinoma to neoadjuvant chemotherapy.

Adult↗
PubMed2005

Can propofol precipitate pancreatitis in patients with Cushing's syndrome?

We encountered two cases of acute pancreatitis in patients with Cushing's disease following transnasal transsphenoidal hypophysectomy. In both cases propofol was used in bolus doses, and is thought to be the probable factor for its development. Since elevated cortisol levels in Cushing's disease poses a threat for pancreatitis, there is a possibility that patients with Cushing's disease might be more prone to acute pancreatitis following propofol administration. Anaesthesiologists and physicians dealing with the management of Cushing's disease need to be aware of this possibility.

Acute Disease↗
PubMed2003

Hemodynamic response to skull pins application in children: effect of lignocaine infiltration of scalp.

BACKGROUND: Skull pins application following local anesthetic infiltration of scalp obtunds hemodynamic changes in adults. No such study is available in children. METHODS: 30 children undergoing elective suboccipital craniectomy with skull pins fixation, were randomly allocated either to control group I, or lignocaine group II. Whereas in group I, pins were applied without any scalp infiltration. In group II, pins were applied 1 min. after scalp infiltration with 0.5% lignocaine (plain) at each pin site. RESULTS: Mean arterial pressure and heart rate were recorded during pinning (peak increase),1,4,7 and 10 min later, and were compared with the baseline (parameters recorded approximately 20 min. after intubation). Mean arterial pressure in group I peaked from 77.0 +/- 9.19 to 113.87 +/- 13.7mmHg (P<0.001) and remained significantly high throughout the study period. In Group II peak increase in mean arterial pressure was from 91.64 +/- 16.39 to 101.85 +/- 15.87 mmHg (P<0.01) and remained high till 1 min. only. Pins placement resulted in significant increase in heart rate only during pinning (peak increase) and up to 1 min. in both the groups (P<0.01). CONCLUSIONS: In children, skull pins placement 1 min. after scalp infiltration with 0.5% lignocaine plain fails to prevent the hemodynamic changes arising during pins placement (peak change) and up to 1 min. after pins placement. However, the technique successfully blocks these changes beyond 1 min. post skull pins fixation.

Anesthetics, Local↗
PubMed2003

Venous air embolism: does the site of embolism influence the hemodynamic changes?

Three hundred and ninety-seven patients undergoing posterior cranial fossa surgery in the sitting position were prospectively studied to evaluate the incidence of venous air embolism (VAE) and its effects on hemodynamics. End-tidal carbon dioxide (ETC02) tension was monitored to diagnose VAE. A sudden and sustained decrease in ETC02 of more than 5 mmHg, in the absence of sudden hypovolemia, was presumed to be the result of VAE. The site of probable air entrainment (whether muscle, bone or tumor) was noted. Hemodynamic consequences were managed symptomatically. ETC02 monitoring detected VAE in 22% of the patients. The highest incidence of embolism resulted from muscles and tumor (40% in each case). Forty-two per cent of patients developed hypotension during the embolic episode (systolic BP less than 100 mmHg). Ten per cent of patients developed ventricular arrhythmias during the embolic episode. Air aspiration was successful in 4.8%. There were no statistically significant differences in the frequency of VAE among the different groups (P>0.05). Also, the frequency of hypotension and ventricular arrhythmias were not significantly different, irrespective of the source of VAE (P>0.05). The general condition of the patients in the preoperative stage had no influence on the incidence of embolism, hypotension or ventricular arrhythmias.

Adolescent↗
PubMed2002

Capecitabine named-patient programme for patients with advanced breast cancer. the UK experience.

Following the encouraging results achieved with the oral fluoropyrimidine capecitabine in clinical trials, a named patient programme was initiated in the UK, through which patients with advanced breast cancer were prescribed capecitabine monotherapy. In this programme, patients were treated with the standard dose of oral capecitabine (1250 mg/m(2) twice daily on days 1-14 of a 21-day treatment cycle). Efficacy and safety data were collected and analysed from 102 patients receiving outpatient treatment with capecitabine. All patients had previously received chemotherapy and for the majority (75%) this was in the metastatic setting. In total, 482 treatment cycles were administered, with a median of 4.5 treatment cycles (range 1-22) per patient. Tumour responses were observed in 20 patients (20%), with an additional 47 patients (46%) achieving disease stabilisation. The median time to disease progression was 4.1 months and median overall survival was 7.7 months. The most common treatment-related adverse events were palmar-plantar erythrodysaesthesia (PPE) (36%) and gastrointestinal toxicities (diarrhoea (33%) and nausea (24%)). Dose reductions due to adverse events were required in 33% of patients, but capecitabine was administered without a dose reduction for 90% of cycles. The results achieved with capecitabine in this named-patient programme confirm that, under 'real practice' conditions, capecitabine is active and well tolerated in patients with advanced breast cancer.

Adult↗
PubMed2002

Case report. Orbital metastasis from gall bladder carcinoma.

Clinical presentation of an extraabdominal metastasis from carcinoma of the gall bladder is rare. Orbital metastasis from gall bladder carcinoma has not been previously reported. We report a case of a 40-year-old woman who developed orbital metastasis from carcinoma of the gall bladder.

Adenocarcinoma↗
PubMed2001

CT-integrated robot for interventional procedures: preliminary experiment and computer-human interfaces.

Pre-operative planning and intra-operative computer interfaces for minimally invasive interventions were investigated with an active robot integrated with a CT scanner. To test the robotic system, a biopsy study was performed using a pig. For pre-operative planning, a virtual needle was superimposed on axial slices and multiplanar reformatted views in correlation with the interventional field. The path of the virtual needle was sent to the robot's controller, and the robot's needle gripper moved into a position congruent with the planned path. Intra-operative controls were then used to drive the needle while keeping the interventionalist's hands out of the direct X-ray beam during CT fluoroscopy. After needle insertion, the imaged and virtual needles were shown to be sufficiently congruent.

Animals↗
PubMed2001

Sympathetic blockade for the relief of chronic pain.

The sympathetic blocks are useful in many ways for relief of chronic pain. The sympathetic block can be caused at pre- and paravertebral sympathetic ganglia eg, stellate ganglia, coeliac plexus and lumbar sympathetic ganglia. Indications for sympathetic blockade are: Complex regional pain syndrome, phantom limb pain, central pain, acute pancreatitis, pancreatic cancer and cancer pain from upper abdominal viscera. Stellate ganglion blockade is required for the diagnosis, prognosis and therapy for painful and other conditions associated with sympathetic dysfunctions of head, neck and upper extremity. Coeliac plexus block is indicated in pain due to intra-abdominal cancer, stemming from organs innervated by coeliac plexus. Lumbar sympathetic block is indicated for diagnosis, prognosis and therapy for painful and other conditions associated with sympathetic dysfunctions like complex regional pain syndrome I and II, herpes zoster, amputation stump pain and inoperable peripheral vascular vasospastic diseases of the lower limb. Indications for superior hypogastric block are the prognostic and therapeutic purposes of cancer pelvic organs--uterus, cervix, bladder, prostate, urethra, testes and ovaries.

Anesthetics, Local↗