Search PubMed⌕ Search

Biomedical subjects

A Sharma

Publications and source records attributed to A Sharma.

At least 397 records · Page 22Linked to original sources
PubMed1998

Dysembryoplastic neuroepithelial tumour.

We report here a classic case of dysembryoplastic neuroepithelial tumour, which was situated in the left frontal lobe of a 13-year-old boy who presented with intractable partial complex seizures since 3 years of age. This tumour entity was first described in 1988, and has been incorporated in the 2nd edition (1993) of the WHO histological typing of CNS tumours. Fewer than 100 cases have been reported from all over the world. To our knowledge, this is the first report of this tumour from India. It is important to recognise this entity since surgery is the only means of cure and radio- or chemotherapy is unwarranted.

Adolescent↗
PubMed1998

Juvenile (calcifying) aponeurotic fibroma of the neck.

A case of juvenile (calcifying) aponeurotic fibroma (JAF) arising in the neck of a 5-year-old female is presented. The lesion was misdiagnosed as fibrous hamartoma of infancy (FHI) on a superficial biopsy prior to total excision of the mass. Only one instance of JAF of the neck has previously been reported; the tumor is usually located in the distal extremities and often recurs following excision. FHI occurs most frequently at and about the axilla and shoulder, and does not recur in most instances.

Calcinosis↗
PubMed1998

An outbreak of post-surgical wound infections due to Mycobacterium abscessus.

An outbreak of post-operative wound infections due to Mycobacterium abscessus is described. During a 5-month period 45 post-surgical patients developed wound infection, manifested by wound breakdown, cellulitis, and discharge and progressing slowly to suppuration and sinus formation. The majority (43/45) had undergone out-patient operations, and 40 had had surgery in the inguinal region. The source of infection was identified as contaminated tap water. A study revealed serious deficiencies in the disinfection and sterilisation techniques employed in the operating theatre (OT), including major defects in the autoclaving machine. The outbreak was controlled after several specific measures were instituted. The patients responded well to treatment with conventional first-line anti-tuberculous drugs administered for 3-8 months. The report highlights the necessity of strict monitoring of disinfection and sterilisation techniques in surgical units and OTs.

Antitubercular Agents↗
PubMed1998

Renal function in Inuit survivors of epidemic hemolytic-uremic syndrome.

We undertook a case-control study to evaluate the renal health of survivors of hemolytic-uremic syndrome (HUS) from the 1991 Arctic epidemic of Escherichia coli O157:H7 gastroenteritis 4 years after the epidemic. Eighteen children who developed HUS during the 1991 epidemic and 18 age- and sex-matched controls from the same community who had uncomplicated gastroenteritis were compared in 1995 for height, weight, blood pressure, urinalysis, and glomerular filtration rate (GFR), measured using continuous subcutaneous infusion of non-radioactive iothalamate. HUS survivors did not differ from controls in height, weight, systolic (HUS 118 mmHg, control 117 mmHg) or diastolic (HUS 64 mmHg, control 62 mmHg) blood pressures. Hematuria was detected more frequently in HUS survivors (11/18 vs. 4/18, P<0.05), but no child had proteinuria. Mean GFR did not differ between the two groups (HUS 159 ml/min per 1.73 m2, control 147 ml/min per 1.73 m2). Survivors of post-enteritic HUS from the 1991 Arctic E. coli 0157:H7 outbreak have excellent renal function 4 years after the epidemic.

Case-Control Studies↗
PubMed1998

The use of pamidronate in three children with renal disease.

The successful use of pamidronate, a bisphosphonate, for the treatment of hypercalcemia and/or osteopenia is reported in three children with renal failure or following renal transplant. Patient 1 was an 11-year-old post renal transplant male who received a single dose of i.v. pamidronate (0.5 mg/kg) for the treatment of acute hypercalcemia associated with a pathological fracture and subsequent immobilization. Prompt resolution of the hypercalcemia was seen. He received a second course of pamidronate (0.5 mg/kg per day for 3 days) for the treatment of osteopenia and has had a subsequent 15% increase in lumbar spine bone mineral content (BMC). Patient 2, a 14-year-old male on peritoneal dialysis, presented with symptomatic hypercalcemia associated with tertiary hyperparathyroidism. A single dose of i.v. pamidronate (0.4 mg/kg) was given with prompt resolution and prolonged control of his hypercalcemia. The third patient was a 16-year-old female, also in renal failure on peritoneal dialysis. Her course had been complicated by marked osteopenia. I.v. pamidronate (0.5 mg/kg per dose) was given on 3 successive days before and after renal transplant in an attempt to stabilize her bone mineral density (BMD) around the time of renal transplantation, when additional glucocorticoid was necessary. Her total body BMC and BMD remained stable pre and post transplant. The treatment was effective and well tolerated in all three patients. Hence pamidronate is safe and effective for the management of hypercalcemia and osteopenia in children with renal failure and/or renal transplant.

Adolescent↗
PubMed1998

Chest imaging in AIDS.

A review of imaging in the acquired immune deficiency syndrome (AIDS) is presented. The imaging features can be conveniently categorized according to whether the presenting complications are infective (bacterial, protozoal, or fungal), bronchiectasis, neoplastic (Kaposi's sarcoma, AIDS-related lymphoma, or lymphoproliferative disease), or a miscellaneous group (non-specific interstitial pneumonitis, persistent generalized lymphadenopathy, or bronchogenic carcinoma).

AIDS-Related Opportunistic Infections↗
PubMed1998

Pseudoexstrophy associated with congenital pouch colon.

Pseudoexstrophy or covered exstrophy is a rare exstrophy variant. The authors report a case of covered exstrophy that presented as a newborn with widely separated pubic bones and rectus muscles, a low-set umbilicus, and a subcutaneous bladder. The anal opening was absent, and there was a complex malformation of the external genitalia consisting of a small, laterally displaced penis and a right-sided ectopic hemiscrotum. Micturition and urinary continence were normal. The child also had a high anorectal malformation with a coexistent type IV congenital pouch colon (CPC) malformation. Both kidneys were normal. Preliminary surgery consisted of a divided sigmoid colostomy proximal to the colonic pouch. The literature is reviewed and the embryogenesis of pseudoexstrophy and its associated malformations are discussed.

Abnormalities, Multiple↗
PubMed1998

Saccadic localization of random dot targets.

The targets for saccadic eye movements in natural visual scenes are spatially extended objects, yet saccades land at a single position within them. To characterize the spatial transformation that determines the saccadic goal position within attended objects, we studied saccadic localization of large patterns of random dots. Saccades landed with a high degree of precision near the center-of-gravity of the patterns (average error < 10%; SDs around the center-of-gravity = 7-11% of target eccentricity). Predictions of landing position were improved by using a weighted center-of-gravity, in which the weight assigned to each dot was reduced by the presence of neighboring dots. Weighting based either on the eccentricity of dots or their position relative to the boundary of the pattern had no effect. The results can be accounted for by a spatial transformation in which the "local signs" of an initial array of detectors, weighted by the activity of each, are averaged to yield the saccadic goal. This model can account for accurate and precise saccadic localization of large targets, while preserving sensitivity to local pattern characteristics. Unlike models of recognition, the boundary of the object has the same status as the internal details.

Female↗
PubMed1998

Cataract surgery in patients with dry eyes.

PURPOSE: To evaluate the potential causes of postoperative complications and the visual outcome after surgery for age-related cataract in dry eyes. SETTING: Tertiary-care multidisciplinary referral medical institution. METHODS: The records of 15 patients (21 eyes) with age-related cataract, a Schirmer value of 5.0 mm or less in 5 minutes, and a tear-film breakup time of 5 seconds or less having complications after cataract surgery were reviewed. Patients were assigned to 1 of 2 groups: dry eye with probable secondary Sjögren's syndrome (Group 1); dry eye without connective tissue disorders (Group 2). The surgical procedure, preoperative and postoperative medications, postoperative complications, and final visual outcome were analyzed. RESULTS: Ten eyes (8 patients) in Group 1 and 11 (7 patients) in Group 2 had cataract surgery. In Group 1, postoperative endophthalmitis developed in 3 eyes and peripheral keratolysis in 4; 5 eyes attained a visual acuity between 6/60 and 6/18 2 years after surgery. In Group 2, filamentary keratitis developed in 6 eyes and peripheral keratolysis in 2 eyes; 6 eyes achieved a visual acuity of 6/12 or better 2 year after surgery. A significant decrease in visual acuity occurred between 3 months and 2 years postoperatively in both Group 1 (P = .010) and Group 2 (P = .0005). CONCLUSION: Cataract surgery in dry eyes had fewer complications and better visual outcome in patients who did not have connective tissue disease than in those who did.

Adult↗
PubMed1998

Localization of C-X-C and C-C chemokines to renal tubular epithelial cells in human kidney transplants is not confined to acute cellular rejection.

Chemokines are important mediators of leucocyte chemoattraction to inflammatory sites. Previous work has shown that the expression of some chemokines is upregulated during renal transplant rejection. The objectives of the present study were to determine whether chemokine expression is increased during renal transplant rejection. Immunohistochemistry was used to localize the C-X-C (alpha) chemokine interleukin-8 (IL-8) and the C-C (beta) chemokines monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-1beta (MIP-1beta) in 30 needle biopsies of human kidney transplants taken for diagnosis of renal dysfunction. Urine samples from transplant patients taken immediately prior to biopsy were assayed for chemokine content using enzyme-linked immunosorbent assays (ELISAs). Results from groups of patients having different clinicopathological diagnoses were then compared. All three chemokines were detected in most renal transplant biopsies showing acute cellular rejection but, although infiltrating leucocytes were often positive, staining was predominantly localized to renal tubular epithelium. Staining for MCP-1 was generally weaker than for the other chemokines, and collecting tubules were usually stained more strongly than proximal convoluted tubules. Tubular epithelial staining was also found in biopsies from patients without signs of acute cellular rejection. There were significantly higher amounts of IL-8 in the urine of patients with acute cellular rejection, even when patients with urinary tract infections were excluded, but mean titres of urinary MIP-1beta did not differ between patient groups. This was also found when titres were normalized for urine volume and creatinine levels. Production of IL-8, MCP-1 and MIP-1beta is not confined to kidney transplants showing acute cellular rejection, and may be a relatively nonspecific response of tubular epithelial cells to renal damage.

Acute Disease↗
PubMed1998

Precursor-dependent indirect pharmacodynamic response model for tolerance and rebound phenomena.

A precursor-dependent model of indirect pharmacodynamic response which can describe tolerance and rebound was characterized in terms of the effects of changes in the fundamental properties of the drug on its response profiles. The model extends previous models by considering inhibition or stimulation of production of the response variable dependent on the amount of precursor which may accumulate or deplete after administration of some drugs. Standardized pharmacokinetic and pharmacodynamic parameters were used for generating dose, plasma concentration, and response-time profiles using computer simulations. The peak response (Rmax) and the time of its occurrence (TRmax) were dependent on the dose, degree of maximum inhibition (Imax) or stimulation (Smax), and drug concentrations causing 50% inhibition (IC50) or stimulation (SC50). The maximum rebound (RBmax) and the time of its occurrence (TRBmax) after a single bolus dose were also dependent on these factors, but were of lesser magnitude and showed relatively later occurrence. Interestingly, values of area between the baseline and effect curve (ABEC) and area between the baseline and rebound curve (ABRC) were equal for each set of conditions for each model, but the latter is reduced when there is a second pathway for loss of precursor. Tolerance occurs because of diverse mechanisms, and the response patterns demonstrated may be helpful in describing tolerance and rebound phenomena for drugs which affect precursor pools.

Dose-Response Relationship, Drug↗
PubMed1998

Phase I trial of paclitaxel and gemcitabine administered every two weeks in patients with refractory solid tumors.

PURPOSE: Paclitaxel and gemcitabine possess broad spectra of clinical activity, distinct mechanisms of cytotoxicity, and are differentially affected by mutations in cell-cycle regulatory proteins, such as bcl-2. This phase I trial was designed to identify the maximum tolerated dose (MTD) and dose limiting toxicities (DLT) of paclitaxel and gemcitabine when both drugs were given together on a once-every-two-week schedule in patients with solid tumors. PATIENTS AND METHODS: A total of 37 patients were treated at nine different dose levels ranging from paclitaxel 75-175 mg/m2 administered over three hours followed by gemcitabinc 1500-3500 mg/m2 administered over 30-60 minutes. Both drugs were administered on day 1 of a 14-day cycle. Dose escalation was performed in a stepwise manner in which the dose of one drug was escalated while the dose of the other drug was kept constant. RESULTS: Dose limiting toxicity (DLT) was observed at dose level 9: paclitaxel 175 mg/m2 and gemcitabine 3500 mg/m2 in the form of grade 4 neutropenia lasting for > or = 5 days (one patient) and grade 3 elevation of alanine aminotransferase (AST/SGPT) (one patient). An analysis of delivered dose intensity (DI) over the first three cycles revealed that higher dosages of both drugs were delivered at dose level 7, paclitaxel 150 mg/m2 and gemcitabine 3000 mg/m2 dose level, than at the MTD, dose level 8, paclitaxel 150 mg/m2 and gemcitabine 3500 mg/m2. Partial responses were confirmed in two patients with transitional cell carcinoma (one of the bladder, one of the renal pelvis) and in one patient with adenocarcinoma of unknown primary. CONCLUSIONS: Paclitaxel and gemcitabine is a promising drug combination that can be administered safely and repetitively on an every-other-week schedule. Using this drug administration schedule, the recommended phase II dose is paclitaxel 150 mg/m2 and gemcitabine 3000 mg/m2.

Adult↗
PubMed1998

Estimation of oral bioavailability of a long half-life drug in healthy subjects.

PURPOSE: To estimate and compare the oral bioavailability of a drug (BMS-187745) administered as single doses of oral solution of either the parent drug or its prodrug (BMS-188494). METHODS: A single-dose, two-period, three-treatment, control-balanced, residual-effect, incomplete block crossover study was completed in 16 healthy male subjects. All subjects received a 10 mg IV infusion of BMS-187745, and a single oral dose of either BMS-187745 (PO1) or BMS-188494 (PO2). A model is proposed to calculate the oral bioavailability of BMS-187745 which has a long half-life; incomplete data points were available to characterize its elimination phase. The plasma concentration-time data obtained following IV infusion of parent drug, and after administration of either PO1 or PO2 treatment were fitted simultaneously with systemic pharmacokinetic parameters shared by both the oral and IV routes of administration. RESULTS: The best simultaneous fittings of the plasma concentration-time data were obtained by using a biexponential pharmacokinetic model with a first-order absorption rate constant. The mean bioavailability (F) values of BMS- 187745 estimated by the proposed model were 26.5% and 2.6% when given as oral solution of its prodrug and as the parent drug. The coefficient of variation (CV) of these F values are reasonable, ranging from 38-40%. In contrast, F calculated by the model-independent AUC method exhibited high CV, ranging from 111-120%. CONCLUSIONS: The oral bioavailability values estimated by the proposed model were more reasonable compared to those calculated by the model-independent AUC method. The proposed approach may be useful for estimating bioavailability of long half-life drugs when incomplete data points are available to characterize their elimination phase.

Administration, Oral↗
PubMed1998

Plasmodium vivax causing pancytopenia after allogeneic blood stem cell transplantation in CML.

A 20-year-old male patient with chronic myeloid leukemia (CML), in chronic phase, underwent allogeneic blood stem cell transplantation in August 1996. Engraftment was well documented in the marrow on day 19, but pancytopenia and mild splenomegaly continued. On day +70, the patient developed severe anemia and had one pyrexial episode. He was detected to have malaria (Plasmodiium vivax). After chloroquin therapy, the pancytopenia reversed completely. We suggest that malaria should be considered as a possible cause of pancytopenia in the post-transplant period in endemic areas.

Adult↗
PubMed1998

Characteristics of indirect pharmacodynamic models and applications to clinical drug responses.

This review describes four basic physiologic indirect pharmacodynamic response (IDR) models which have been proposed to characterize the pharmacodynamics of drugs that act by indirect mechanisms such as inhibition or stimulation of the production or dissipation of factors controlling the measured effect. The principles underlying IDR models and their response patterns are described. The applicability of these basic IDR models to characterize pharmacodynamic responses of diverse drugs such as inhibition of gastric acid secretion by nizatidine and stimulation of MX protein synthesis by interferon alpha-2a is demonstrated. A list of other uses of these models is provided. These models can be readily extended to accommodate additional complexities such as nonstationary or circadian baselines, equilibration delay, depletion or accumulation of a precursor pool, sigmoidicity, or other mechanisms. Indirect response models which have a logical mechanistic basis account for time-delays in many responses and are widely applicable in clinical pharmacology.

Humans↗
PubMed1998

Chest wall tuberculosis simulating breast carcinoma: imaging appearance.

Tuberculosis of the breast is a rare disease. Tubercular abscesses predominantly affecting the soft tissues are also very infrequent. A case of chest wall tuberculosis secondarily involving the breast presenting as a hard, fixed lump simulating mammary carcinoma is presented here. There was no evidence of pleural or pulmonary tuberculosis.

Breast Diseases↗