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Biomedical subjects

A Saxena

Publications and source records attributed to A Saxena.

At least 127 records · Page 7Linked to original sources
PubMed1999

Stenosis in the aorta caused by non-specific aortitis: results of treatment by percutaneous stent placement.

AIM: To evaluate the short-term results of percutaneous stent placement in treating stenosis in the aorta caused by non-specific aortitis (Takayasu's disease). METHOD: Five patients were treated by this method, all of whom had uncontrolled hypertension, haemodynamically significant stenosis in the aorta and a clinically inactive disease. Stents were placed to treat an obstructing dissection in four and recurrent stenosis in one patient. All procedures were carried out via the percutaneous transfemoral route, utilizing self-expanding stents. RESULTS: The lesion was located in the thoracic aorta in three patients and in the abdominal aorta in two patients. The stenosis decreased from 81+/-2 to 7+/-3%, the pressure gradient fell from 97+/-5 to 9+/-2 mmHg, the blood pressure improved from 200+/-3/124+/-2 to 131+/-2/81+/-2 mmHg, and the drug requirement fell from 4+/-.2 to 1.3+/-.3 (P value for all <0.001). No complication was encountered. At follow-up at 13+/-4 months, all of the patients had improved clinically. Intimal hyperplasia within the stent was seen in two patients who underwent follow-up angiograms. CONCLUSION: Percutaneous aortic stenting is useful in treating selected patients with non-specific aortitis. Further information about the long-term behaviour of intimal hyperplasia and the response of stented segments to the aging process needs to be understood before elective stenting in this young patient population can be advocated.

Adolescent↗
PubMed1999

Pulmonary autograft: should it be used in young patients with rheumatic disease?

BACKGROUND: Although pulmonary autograft is being increasingly used to replace the diseased aortic valve with excellent long-term results, its use in the population with rheumatic disease still needs careful evaluation. PATIENTS AND METHODS: From October 1993 through March 1998, 102 patients underwent aortic valve replacement with a pulmonary autograft (Ross procedure). The mean age was 27.9 +/- 4.2 years (range, 0.8-56 years). The cause was rheumatic disease in 75 patients (73%), bicuspid aortic valve in 26 patients (26%), and myxomatous aortoarteritis in 1 patient (1%). The root replacement technique was used in all. In addition, 31 patients had 33 associated procedures: mitral valve repair (n = 15 patients), open mitral commissurotomy (n = 15 patients), tricuspid repair (n = 2 patients), and homograft mitral valve replacement (n = 1 patient). RESULTS: Operative mortality was 6.9% (7 patients). Late mortality was 7.8% (8 patients). Follow-up ranged from 1 to 60 months (mean, 25.3 +/- 15.4 months) and was 98% complete. Two patients required reoperation for failed mitral valve repair, and 2 other patients underwent reoperation for failure of both the autograft and mitral valve repair. Echocardiographic assessment showed moderate to severe aortic regurgitation in 13 patients, along with thickening of the autograft. All of these patients had rheumatic disease and were young (<30 years). Ten of these patients had undergone associated mitral valve procedure. Morphologic and histopathologic examination of explanted autografts showed features compatible with rheumatic valvulitis. CONCLUSION: Pulmonary autograft is susceptible to rheumatic involvement. Young age (<30 years) and associated mitral valve disease are significant risk factors for autograft failure in patients with rheumatic disease. Use of pulmonary autograft in this subgroup of patients requires a cautious approach.

Adolescent↗
PubMed1999

The assessment of cancer pain in north India: the validation of the Hindi Brief Pain Inventory--BPI-H.

The status of pain treatment for cancer patients in India is largely undocumented. Although many languages and dialects are spoken throughout the country, millions of persons in North India speak Hindi. This project developed and validated a Hindi version of the Brief Pain Inventory (BPI-H), a short measure of pain and pain interference that has been shown to be relatively free of cultural or linguistic influences. In the validation process, we were able to administer both the Hindi and English versions of the BPI to a sample of bilingual (Hindi and English) patients. The English and Hindi versions of the BPI were very similar in their psychometric properties, supporting the reliability and construct validity of the Hindi version. As with other language versions of the BPI, factor analysis of the BPI-H items results in severity and interference subscales. We followed the validation with an examination of the status of cancer pain management in a major northern Indian cancer center, based on 200 patients with pain who spoke only Hindi. Using a conservative measure of analgesic prescription adequacy (the Pain Management Index), three-fourths of Hindi-speaking cancer patients in this study were inadequately treated by World Health Organization (WHO) recommendations. The results of this study encourage the development of other forms of the BPI in the many languages of India, and the use of the instrument in studies of the epidemiology and treatment of cancer pain.

Adult↗
PubMed1999

Double switch for congenitally corrected transposition of the great arteries.

OBJECTIVE: To evaluate the early and medium term results of operations for congenitally corrected transposition of the great arteries (CCTGA) wherein the left ventricle becomes the systemic ventricle. METHODS: Fourteen patients with CCTGA who underwent anatomic repair from 1994 to 1998 were placed in one of two groups: those without pulmonic stenosis (PS) (N = 7) and those with PS (N = 7). Main associations in the group without PS were: severe left atrioventricular (AV) valve regurgitation (N = 4), ventricular septal defect (VSD) (N = 4), criss-cross AV connection (N = 1), and hypoplasia of the morphologic RV (N = 1). Main associations in the group with PS were: VSD (N = 7), anomalous pulmonary venous drainage (N = 2) and major aorto-pulmonary collaterals (N = 1). All patients in the group without PS underwent an arterial switch operation and all except one had a modified senning repair for atrial rerouting for anatomic correction. All seven patients with PS underwent a Rastelli repair and all except one needed a modified senning repair. RESULTS: Early survivorship in both groups was 6/7. Follow-up ranges from 1 month to 48 months. The mean left ventricular ejection fraction (LVEF) in the arterial switch and senning patients was 65% and in the Rastelli and atrial rerouting was 52%. None of the survivors except one have any significant mitral regurgitation (MR). The one exception resulted from iatrogenic damage to a chorda during VSD closure. All except two patients are class I symptomatic and all are in normal sinus rhythm. CONCLUSION: Satisfactory early and mid term results of anatomic repair support the double switch option as the procedure of choice for patients of CCTGA amenable to biventricular repair.

Adolescent↗
PubMed1999

Laser light scattering immunoassay for malaria.

Laser light scattering immunoassay (LIA) was proposed as a prospective diagnostic method for the detection of antibody (or antigen) by monitoring the agglutination of antigen (or antibody) coated carrier particles using dynamic light scattering (DLS) as probe. LIA is a very sensitive assay as it can detect microscopic immune complexes even when antibody (or antigen) level is low. A sizeable number of human sera collected from malaria endemic areas and hospitals have been analysed by ELISA using Pf parasite lysate or a RESA derived synthetic peptide as antigen parallel to LIA using Pf antigen coated polystyrene latex beads. Comparative analysis of data suggests LIA to be as good as ELISA and possibly better in terms of sensitivity and simplicity. LIA can be a simple and inexpensive immunoassay suitable for field use and mass application.

Antigens, Protozoan↗
PubMed1999

A combination of abnormal immunoarchitecture and reproducible clonal bands identifies the biologic nature of cutaneous B-cell infiltrates.

In the multiparametric evaluation of cutaneous B-cell infiltrates (CBIs), immunoarchitectural features have been underused, and B-cell clonality alone has limited clinical usefulness. Our aim was to assess the usefulness of immunoarchitectural abnormalities (IAs) and clonality in the diagnosis of CBIs. On 39 CBIs, immunohistochemistry was performed using anti-CD45, anti-CD45RO, anti-CD3, anti-CD20, anti-CD21, and anti-CD35, and polymerase chain reaction was used to detect immunoglobulin heavy chain rearrangement. There were 33 cutaneous lymphoid hyperplasias (CLHs) and 6 cutaneous B-cell lymphomas. IAs were present in 9 lesions and clonal bands in 14 lesions. In 6 cutaneous B-cell lymphomas, IAs were associated with pure and reproducible clonal bands. IAs in 3 CLH lesions with a superficial infiltrate were not associated with clonal bands. Clonal bands in 8 CLH lesions without IAs were not reproducible from deeper sections; furthermore, in 5 of 8 cases, these were present against a background smear. A combination of IAs and clonality is a useful adjunct in the diagnosis of CBIs.

Adolescent↗
PubMed1999

The safety and efficacy of prophylactic ondansetron in patients undergoing modified radical mastectomy.

UNLABELLED: We aimed to evaluate the antiemetic efficacy, safety, and clinical utility of prophylactic ondansetron administered at the end of the surgery for the prevention of postoperative nausea and vomiting (PONV) in a homogenous population of 54 women undergoing modified radical mastectomy (MRM). A standard general anesthetic and perioperative analgesic technique were used. After surgery, patients received either saline placebo or ondansetron 4 mg IV. Episodes of PONV, as well as rescue antiemetic requirements, were recorded for the first 24 h after surgery. The 24-h incidence of PONV (33.3% vs 81.5%; P = 0.0010) was significantly lower in the ondansetron group. The severity of PONV, evaluated by the number of emetic episodes per patient (1.59+/-1.90 vs 0.29+/-0.66; P = 0.0029), and the rescue antiemetic requirement (59.2% vs 14.8%; P = 0.0019) was significantly lower, in the ondansetron group. Patient satisfaction scores and number needed to prevent PONV (2.07) were significantly better and therapeutically more favorable in the ondansetron group. The incidence of adverse events such as headache, dizziness, and increased liver enzyme levels (number needed to harm = infinity) was similar in both groups. Administered at the end of the surgery in adult female patients undergoing general anesthesia for MRM, ondansetron 4 mg is effective and safe in preventing PONV. We recommend the clinical practice of routine prophylactic ondansetron to prevent PONV after MRM, as it significantly improves perioperative patient satisfaction and outcome. IMPLICATIONS: We evaluated the antiemetic efficacy, safety, and routine use of prophylactic ondansetron, a "gold standard" antiemetic, in women undergoing radical breast surgery who were at a high risk of postoperative vomiting. We analyzed more meaningful "true" and "therapeutic" outcome measures, and we conclude that prophylactic ondansetron is safe and effective and that its routine use is justified.

Adult↗
PubMed1999

Hysteresis and avalanches in two-dimensional foam rheology simulations.

Foams have unique rheological properties that range from solidlike to fluidlike. We study two-dimensional noncoarsening foams of different disorder under shear in a Monte Carlo simulation, using a driven large-Q Potts model. Simulations of periodic shear on an ordered foam show several different response regimes. At small strain amplitudes, bubbles deform and recover their shapes elastically, and the macroscopic response is that of a linear elastic cellular material. For increasing strain amplitude, the energy-strain curve starts to exhibit hysteresis before any topological rearrangements occur, indicating a macroscopic viscoelastic response. When the applied strain amplitude exceeds a critical value, the yield strain, topological rearrangements occur, the foam starts to flow, and we observe macroscopic irreversibility. We find that the dynamics of topological rearrangements depend sensitively on the structural disorder. Structural disorder decreases the yield strain; sufficiently high disorder changes the macroscopic response of a foam from a viscoelastic solid to a viscoelastic fluid. This wide-ranging dynamical response and the associated history effects of foams result from avalanchelike rearrangement events. The spatiotemporal statistics of rearrangement events do not display long-range correlations for ordered foams or at low shear rates, consistent with experimental observations. As the shear rate or structural disorder increases, the topological events become more correlated and their power spectra change from that of white noise toward 1/f noise. Intriguingly, the power spectra of the total stored energy also exhibit this 1/f trend.

Journal Article↗
PubMed1999

Intrapericardial streptokinase in purulent pericarditis.

Six consecutive children with proven purulent pericarditis were treated with pericardial irrigation with streptokinase. Mean (SD) 861 (678) ml (range 240-2000) of thick purulent fluid was drained, and five children had complete clearance of the pus within 3-8 days. One child developed intrapericardial haemorrhage with a submitral pseudoaneurysm and underwent patch closure of the neck of the aneurysm as well as anterior pericardiectomy. Follow up of 13 to 30 months revealed no pericardial constriction.

Child↗
PubMed1999

Comparison of perioperative morbidity in patients with ovarian malignancy undergoing radical cancer surgery with or without prior chemotherapy.

Evaluation was undertaken of the effect of chemotherapeutic drugs on the perioperative morbidity of patients with ovarian malignancy undergoing radical surgery. Twenty patients who had received cytotoxic drugs pre-operatively (group I) were compared with 11 patients in whom radical surgery was the first line of treatment (group II). Pre and post-operative cardiac, pulmonary, renal, hepatic and coagulation functions were compared in both groups, as well as the critical intra- and post-operative events like cardiac pump failure, respiratory dysfunction, rhythm disturbances, blood loss, etc. Demographic data, ASA status, biochemical and haematological parameters and cardiac ejection fractions were comparable in the two groups but patients in group I had significantly higher left ventricular end diastolic dimensions (P < 0.01). A higher number of patients in group I had pre-operative respiratory and coagulation factor abnormalities but critical intra- and post-operative events in both groups were comparable. The surgical time was significantly (P < 0.01) longer in group I (5.5 +/- 2.5 h) as compared to group II (4.5 +/- 1.5 h). One patient with extensive tumour spread and pre-operatively deranged coagulation profile (group I) died of disseminated intravascular coagulation in the post-operative period. It is concluded that patients with advanced ovarian malignancy, treated with cytotoxic drugs are more likely to have pre-operative cardiac, respiratory and coagulation abnormalities, which should be managed by thorough pre-operative evaluation and intensive intra- and post-operative monitoring.

Adult↗
PubMed1999

Tracheal agenesis.

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Abnormalities, Multiple↗
PubMed1998

Gene structure of the human amiloride-sensitive epithelial sodium channel beta subunit.

ENaC functions in the transport of sodium ions across epithelial cells and consequently regulates blood volume and pressure. ENaC complex includes at least three different subunits, alpha, beta, and gamma, which are developmentally regulated and differentially controlled by aldosterone. In this study, we determined the exon-intron organization of the beta ENaC subunit by sequencing genomic DNA from three subjects from three different ethnic groups. The results showed that the coding region of the human betaENaC gene (SCNN1B) extends from exon 2 to exon 13. No polymorphism was observed in the examined subjects, indicating strict conservation of the coding region sequence. The introns of beta subunit gene are located at exactly the same positions as in the alpha and gamma subunits, although these proteins share only 26-32% sequence identity. These results thus elucidate the gene structure of the beta subunit and indicate that exon-intron architecture of the three genes encoding the three subunits of ENaC have remained highly conserved despite the divergence of their sequences.

Amiloride↗
PubMed1998

Crystallization and preliminary X-ray crystallographic studies on apolipoprotein H (beta2-glycoprotein-I) from human plasma.

Apolipoprotein-H (Apo-H, Mw approximately 50 kDa) is a carbohydrate-rich human-plasma protein which exists in blood serum in the free form as well as distributed between several classes of lipoproteins. Single crystals of apo-H have been obtained and crystallographic data sets have been collected. The crystals belong to the orthorhombic space group C2221, with cell dimensions a = 158. 47, b = 169.25, c = 113.28 A (at 100 K). The data indicate that the crystallographic asymmetric unit contains one tetramer of the protein.

Crystallization↗
PubMed1998

The pH dependence of dealkylation in soman-inhibited cholinesterases and their mutants: further evidence for a push-pull mechanism.

Bimolecular rate constants for the inactivation of recombinant (r) human (Hu) butyrylcholinesterase (BChE) with P(S)C(S)- and P(S)C(R)-2-(3,3-dimethylbutyl) methylphosphonofluoridate (soman) are (92 +/- 7) x 10(6) M-1 min-1 and (13.7 +/- 0.8) x 10(6) M-1 min-1 at pH 7.4, mu = 0.1 M and 25 degreesC. Mutations of E197(199) to D or Q and W82(84) to A result in reductions in the rate constants for inactivation with P(S)C(S)-soman 4.3-, 11.8-, and 263-fold and with P(S)C(R)-soman by 6.5-, 47.3-, and 685-fold, respectively. The pH dependence of dealkylation (aging) in r mouse (Mo) acetylcholinesterase (AChE) and rHu BChE and their mutants inactivated with P(S)C(S)- and P(S)C(R)-soman was compared. Best-fit parameters for the asymmetric bell curves for the adducts of wild-type Mo AChE are pK1 = pK2 = 4.0-4.9 and pK3 = 5.2-6.6. These pKs are consistent with the involvement of two carboxylic acids, possibly E202(199) and either E334(327) or E450(443), and H447(440)H+ in the dealkylation of AChE. E202Q MoAChE inactivated with the soman diastereomers yielded pK3 = 5.5-5.8. Nearly symmetric pH curves for soman-inhibited wild-type and E197D Hu BChE gave pK2 = 3.7-4.6 and pK3 = 7.3-8.0, but much lower, pK3 approximately 5, for the corresponding adduct of the E197Q mutant. Dealkylation in soman-inhibited BChE is consistent with the participation of one carboxylic acid side chain and H438(440)H+. Maximal rate constants for dealkylation (kmax) are 1-6 min-1 for AChE and 2 min-1 for BChE at 25 degreesC. The W82 to A mutation in BChE results in the largest reduction, 2500-6000-fold, in the rate constant for dealkylation. The reduction in the rate constants for dealkylation in the E197 mutants is highly pH dependent. The solvent isotope effects at the pH maxima are 1.3-1.4, indicating unlikely preprotonation or proton in "flight" at the enzymic transition states. The new results support the push-pull mechanism of dealkylation in soman-inhibited cholinesterases proposed previously.

Acetylcholinesterase↗
PubMed1998

Laser light scattering immunoassay: an improved data analysis by CONTIN method.

Laser light scattering immunoassay (LIA) is a diagnostic method for the detection of antibody by monitoring the agglutination of antigen carrier particles mediated by antibody, using dynamic light scattering (DLS) as probe. We have used this method for the detection of antibody to P. falciparum that cause malaria. The data were analysed using CONTIN method and the superiority of the distribution analysis over the conventional interpretation of the data in terms of mean diffusion coefficient or hydrodynamic radius is discussed in detail.

Agglutination↗
PubMed1998

Synthesis and anticholinesterase activity of huperzine A analogues containing phenol and catechol replacements for the pyridone ring.

Based upon modeling results obtained using the crystal structure of huperzine A in complex with acetylcholinesterase (AChE), two novel analogues of this potent AChE inhibitor were designed with phenol or catechol rings replacing the pyridone ring. From the modeling studies, the catechol analogue appeared capable of replacing one of the crystallographic waters bridging huperzine with Tyr 130 and Glu 199 of AChE. The synthesis of these materials by use of a palladium catalyzed bicycloannulation strategy is detailed together with the results of AChE inhibition assays.

Alkaloids↗
PubMed1998

Cardiac myxomas: clinical and echocardiographic profile.

We reviewed our clinical and echocardiographic experience in 70 consecutive patients with 73 cardiac myxomas, diagnosed over an 11 year period. There were 21 males and 49 females, ages ranged from 18 to 80 years. Only in 5.7% cases was the diagnosis of myxomas made clinically. 88.6% cases were initially diagnosed as having: mitral valve disease (70%), tricuspid valve disease (10%), ischemic heart disease (5.7%), cardiomyopathy (2.9%), and the remaining 5.7% were detected during family screening and follow-up. The mean duration of symptoms was 10.6 months. The commonest symptom was dyspnoea (80%), followed by constitutional symptoms (45.7%), embolization (30%), palpitation (25.7%), syncope (15.7%), pedal oedema (15.7%) and pain chest (12.9%). The sites of myxomas were as follows: left atrium, 58; right atrium, 9; and, biatrium, 3. All myxomas except 3 were attached to the interatrial septum. The site, size, shape, attachment, mobility, prolapse into ventricle, and surface characteristic of myxomas were accurately assessed by 2D-echocardiography and confirmed in all (65 of 70) who underwent surgery. When the morphological characteristic of myxomas were studied and correlated with clinical features large left atrial myxoma size was closely related with constitutional symptoms, congestive heart failure, with syncope and auscultatory findings suggestive of mitral valve disease, whereas smaller myxoma size and irregular surface were associated with embolization. Constitutional symptoms were only present in left atrial myxoma. Post-operative mean echocardiographic follow-up of 60 months showed no recurrence except in 2 with familial myxoma. We conclude that the majority of myxomas mimic many cardiovascular diseases and were detected in symptomatic patients, so a high index of clinical suspicion is important for its early and correct diagnosis. The size and appearance of the myxomas correlated with the presenting symptoms.

Adolescent↗