Search PubMed⌕ Search

Biomedical subjects

R Bansal

Publications and source records attributed to R Bansal.

At least 37 records · Page 2Linked to original sources
PubMed2001

ACVR1B (ALK4, activin receptor type 1B) gene mutations in pancreatic carcinoma.

DPC4 is known to mediate signals initiated by type beta transforming growth factor (TGFbeta) as well as by other TGFbeta superfamily ligands such as activin and BMP (bone morphogenic proteins), but mutational surveys of such non-TGFbeta receptors have been negative to date. Here we describe the gene structure and novel somatic mutations of the activin type I receptor, ACVR1B, in pancreatic cancer. ACVR1B has not been described previously as a mutated tumor-suppressor gene.

Activin Receptors, Type I↗
PubMed2001

Detection of a mixed-backbone oligonucleotide (GEM 231) in liver and tumor tissues by capillary electrophoresis.

A simple, rapid and sensitive method has been developed and validated for the analysis of a mixed-backbone oligonucleotide (GEM 231) in tumor tissues. The analysis was performed using a capillary electrophoresis (CE) system with UV detection. An extended light path (bubble cell) capillary column of 64.5 cm (effective length 56 cm) x 50 microm I.D. is used as the separation column. The optimized chromatographic conditions were background electrolyte: sodium borate buffer (60 mM, pH 9.1), electrokinetic injection: 10 s, applied voltage: 30 kV, detection at lambda = 210 nm. A linear relationship was observed between the peak area and the amount of GEM 231 in the range of 1.0-1000 microg/ml. The lower detection limit of the drug was 100 pg with an average recovery of about 75 +/- 5%. The inter-day and intra-day relative standard deviations were <10%. Assay validation studies revealed that CE method is reproducible and specific for the determination of GEM 231 in tissue homogenates with a run time of less than 5 min.

Animals↗
PubMed2001

Concomitant traumatic coronary artery and tricuspid valve injury: a heterogeneous presentation.

Blunt thoracic trauma resulting in both tricuspid valve rupture and coronary artery injury is uncommon, encompasses a large spectrum of presentations and, therefore, can be difficult to diagnose. This report illustrates the heterogeneous presentation and clinical course of two patients with such a combination of cardiac injuries. The patient with associated right coronary artery dissection developed progressive right ventricular failure over a 12-year period before successful surgical repair, whereas another patient with left anterior descending coronary artery thrombosis required urgent operation for acute right ventricular dysfunction and hemodynamic decompensation.

Accidents, Traffic↗
PubMed2001

Central motor conduction studies in patients with Guillain Barré syndrome.

To study the central nervous system involvement in Guillain Barre (GB) syndrome, 30 patients with GB syndrome were subjected to clinical evaluation, muscle testing as per Medical Research Council (MRC) scale, disability score on a 0-5 scale and central motor conduction studies to abductor digiti minimum (ADM), abductor pollicis bravis (APB) and tibialis anterior (TA) bilaterally. Outcome was defined at the end of 3 months into complete, partial and poor. Their age ranged between 12 and 61 years (mean 3.2) and 11 of them were females. At the peak of weakness, the limb muscle power was grade 0 in 8, grade I-II in 10 and grade III-IV in 12 patients. Grade 5 disability was present in 12, grade 4 in 12 and grade 3 in 6 patients. One of these patients had grade 3 muscle power. Central motor conduction time (CMCT) correlated with muscle power, disability score and outcome. Two of our patients expired during the acute stage and 23 could be followed up till 3 months. Three patients recovered completely, 15 partially and 5 had poor recovery. It can be concluded that mild prolongation of CMCT although occurs frequently in the patients with GB syndrome, however, pronounced slowing of CMCT is rare and may suggest central involvement.

Adolescent↗
PubMed2000

Expression of rab GTP-binding proteins during oligodendrocyte differentiation in culture.

Oligodendrocytes (OLs) synthesize and transport vast amounts of proteins and lipids from the cell body to the morphologically and biochemically distinct domains of the myelin membrane. From our prediction that regulators of vesicular transport should be up-regulated at the time of myelin production, we hypothesized that the up-regulated and unidentified small GTPases found by Huber et al. [1994a] may be Rab proteins. We have analyzed the mRNA expression of rabs in OLs, and have detected rabs 10, 11b, 18, 24, 26, and 28 in addition to rabs that were found previously. Our data show that among the Rabs so far detected during differentiation, only Rabs 5a and 8a exhibited up-regulation in addition to the previously published Rab3a (Madison et al. [1999], J. Neurochem. 72:988-998). We discuss the limited extent of up-regulation of rabs in the context of the presumed necessity for an increase in Rab activity during myelin assembly.

Amino Acid Sequence↗
PubMed2000

PDGF and FGF-2 signaling in oligodendrocyte progenitor cells: regulation of proliferation and differentiation by multiple intracellular signaling pathways.

In this paper we address the linking of platelet-derived growth factor (PDGF) and basic fibroblast growth factor (FGF-2) to intracellular signaling molecules in oligodendrocyte progenitors. It is demonstrated that both growth factors activate downstream targets similar to those shown for protein kinase C (PKC) activation. Yet, neither the arrest of terminal oligodendrocyte differentiation nor the proliferation induced by PDGF or FGF-2 can be antagonized by inhibition of PKC. Rather, p42/p44 mitogen-activated protein kinase (MAPK), p38 MAPK, and pp70 S6 kinase were found to be necessary for the mitogenic activity of PDGF and FGF-2. Paradoxically, these kinases were also necessary for the onset of oligodendrocyte differentiation in control cells. In addition, cAMP-dependent kinase A (PKA) activation inhibited the mitogenic response of oligodendrocyte progenitors to FGF-2. Taken together, the molecular mechanism that controls oligodendrocyte lineage progression is operated by at least two signal pathways, which interfere either with proliferation and/or differentiation of oligodendrocyte progenitors.

Animals↗
PubMed1999

Negative regulation of oligodendrocyte differentiation by galactosphingolipids.

Galactocerebroside and sulfatide, major galactosphingolipid components of oligodendrocyte plasma membranes and myelin, are first expressed at a critical point, when progenitors cease to proliferate and commence terminal differentiation. We showed previously that an antibody to galactocerebroside/sulfatide arrested terminal differentiation, suggesting a role for these galactolipids in oligodendrocyte differentiation. We have now investigated the differentiation of oligodendrocytes (1) in response to other anti-galactolipid antibodies, showing that anti-sulfatide O4 but not anti-galactocerebroside O1 blocks terminal differentiation, perhaps by mimicking an endogenous ligand, and (2) in a transgenic mouse unable to synthesize these lipids because of mutation of the gene for ceramide galactosyltransferase, a key enzyme for galactosphingolipid synthesis. We find that galactosyltransferase mRNA expression begins at the late progenitor [pro-oligodendroblast (Pro-OL)] stage of the lineage and that the late progenitor marker pro-oligodendroblast antigen is not synthesized in the absence of galactosyltransferase. The principal outcome of the elimination of these galactolipids is a two- to threefold enhancement in the number of terminally differentiated oligodendrocytes both in culture and in vivo. Because the general pattern of differentiation and the level of progenitor proliferation and survival appear to be unaltered in the mutant cultures, we conclude that the increased number of oligodendrocytes is caused by an increased rate and probability of differentiation. In agreement with these two experimental approaches, we present a model in which galactosphingolipids (in particular galactocerebroside and/or sulfatide) act as sensors and/or transmitters of environmental information, interacting with endogenous ligands to function as negative regulators of oligodendrocyte differentiation, monitoring the timely progress of Pro-OLs into terminally differentiating, myelin-producing oligodendrocytes.

Animals↗
PubMed1999

A minimax entropy registration framework for patient setup verification in radiotherapy.

In external beam radiotherapy (EBRT), patient setup verification over the entire course of fractionated treatment is necessary for accurate delivery of a specified dose to the tumor. We are working on the development of a minimax entropy registration framework for patient setup verification using dual portal images and the treatment planning 3D CT dataset. In this paper, we present an overview of our registration framework, where an iteratively and automatically estimated segmentation of the portal image is utilized to more accurately and robustly register the portal image to the 3D treatment-planning CT data. In addition, we describe initial testing of this approach. We note that, due to low resolution and low contrast of the portal images, this registration presents a difficult problem. We also note that the registration of the images in our proposed method is guided by the bony structure visible in the portal and the 3D CT images. However, since the prostate can move with respect to the pelvic bone, we propose using ultrasound images to quantify this movement.

Algorithms↗
PubMed1999

Cost effectiveness of EUS for preoperative localization of pancreatic endocrine tumors.

BACKGROUND: Endoscopic ultrasonography (EUS) is highly accurate in the localization of small pancreatic tumors. We determined the cost effectiveness of EUS used early in the preoperative evaluation of pancreatic endocrine tumors. METHODS: In a study with a case-control design, 36 patients (19 men, 17 women) who underwent preoperative EUS were matched retrospectively with 36 patients who underwent surgical exploration immediately before the introduction of EUS. The number, cost, and effectiveness of preoperative localization studies, days of hospitalization, and surgical and anesthesia times were assessed. RESULTS: The EUS group had reduced charges for preoperative localization studies: $2620 versus $4846 per patient (p < 0.05), largely because of reductions in the number of diagnostic angiograms and venous sampling procedures performed. Surgical and total anesthesia times were decreased, as were the number of preoperative admissions for angiographic procedures. The cost-effectiveness ratio for the EUS group was $3144 per tumor localized compared with $5628 per tumor localized for the group treated before EUS became available (p < 0.05). CONCLUSION: EUS is highly accurate in the localization of pancreatic neuroendocrine tumors and is cost effective when used early in the preoperative localization strategy. EUS decreased the need for additional invasive tests and avoided unnecessary morbidity and resource consumption. EUS should play a primary role in preoperative localization of pancreatic neuroendocrine tumors.

Angiography↗
PubMed1999

Midbrain infarction: a rare presentation of cryptococcal meningitis.

A 20-year-old farmer who had headache and fever for 1 month, suddenly developed left hemiplegia, tremor in left arm and titubation followed by deep coma. Cranial CT scan revealed an infarction in right crus of midbrain. His CSF revealed 66 mg/dl protein, 10 lymphocytes/mm3, and 70 mg/dl glucose. CSF was positive for cryptococcal antigen. He improved following i.v. amphotericin 0.5 mg/kg and fluconazole 200 mg daily, continued for 6 and 12 weeks respectively. Infarctions though rare in cryptococcal meningitis should be considered in patients with chronic meningitis with vasculitis.

Adult↗
PubMed1999

Effect of increased brain GABA concentrations on breathing in unanesthetized newborn rabbits.

Evidence suggests that gamma-aminobutyric acid (GABA) is involved in control of breathing and in the hypoxia-related ventilatory depression in newborns. However, this evidence is obtained mainly from studies on anesthetized animals. Because anesthesia may interfere with the GABA system, the objectives of our study were to examine effects of GABA on ventilation (V(E)) and ventilatory response to hypoxia and to reveal effects of repeated hypoxia on GABA concentrations in unanesthetized newborns. The study was performed in rabbits in two age groups: 1-3 days old (group I) and 10-14 days old (group II). To increase brain endogenous GABA concentrations, rabbits were injected with an inhibitor of GABA transaminase, aminooxyacetic acid (AOAA; 20 mg/kg i.p.). To prevent postmortem formation of GABA, at the end of experiments the rabbits received an inhibitor of glutamic acid decarboxylase, IP-3-mercaptopropionic acid (100 mg/kg i.p.). Animals were studied in normoxia alone, or they were exposed for 15 min to 8% O(2) before and 10 and 35 min after saline or AOAA. GABA concentrations were measured in brainstem, cerebrum, and cerebellum by means of a capillary electrophoresis. In group I, AOAA had no respiratory effects. In group II, AOAA decreased V(E), tidal volume, and mean inspiratory flow in normoxia and reversed V(E) decline during hypoxia 10 min after the injection, GABA concentrations were not age dependent and the highest in the brainstem. Repeated hypoxia increased the cerebellar GABA concentrations and had no effect in group I. These results imply that in unanesthetized rabbits, GABAergic neurotransmission in the respiratory control network becomes functional by the 2nd week of life, but it does not contribute to the biphasic ventilatory response to moderate hypoxia. In contrast, GABA-evoked block of the cerebellar inhibitory input during hypoxia may be responsible for the reversal of the V(E) decline in unanesthetized newborns.

4-Aminobutyrate Transaminase↗
PubMed1998

Myelitis: a rare presentation of mumps.

We report a rare case of mumps myelitis in which parotid swelling appeared 3 days after the symptoms of myelitis. A 10-year-old boy presented with acute paraplegia of grade I-II on MRC (Medical Research Council) scale and retention of urine with normal sensations. Central motor conduction to tibialis anterior (CMCT-TA) on the right side was 32 ms and 24 ms on the left side. Spinal MRI revealed hyperintense signal changes extending from C3 to T12. After 5 days of methylprednisolone therapy, there was marked improvement in weakness, micturition normalized and CMCT-TA also returned to normal. MRI repeated after 1 month was also normal. This response seems to be due to antiedema and to the antiinflammatory effect of methylprednisolone, because of a temporal relationship between MPS and clinical improvement. However, the possibility of natural recovery cannot be ruled out.

Child↗
PubMed1998

Relation of mast cell, nerve and fibrosis in appendix.

The relationship of mast cells, nerves and fibrosis was studied in 50 cases of Appendix using simple histochemical technique. In the mucosa, the mast cell number was greater in the early stages of fibrosis. Both in the mucosa and submucosa mast cells were found closely associated with neural tissue. As the fibrosis increased this association between mast cells and neural tissue was retained only in the submucosa.

Appendicitis↗
PubMed1998

A study of 70 cases of cutaneous metastases from internal carcinoma.

A retrospective analysis of 70 patients with metastatic cutaneous nodules, was conducted in the department of pathology, Kasturba Medical College, Mangalore. The available clinical records and histologic material of these cases were reviewed. In last few years fine needle aspiration cytology (FNAC) was being used as the main diagnostic tool. The commonest primary site of cutaneous metastasis in this study was gastro-intestinal tract (46.7%) in males and breast (32%) in females. Abdomen (including umbilical nodules) was found to be the most frequent site for metastatic cutaneous nodule.

Female↗