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N H Patel

Publications and source records attributed to N H Patel.

At least 91 records · Page 5Linked to original sources
PubMed1991

A comparison of controlled release metoclopramide and domperidone in the treatment of nausea and vomiting.

Dopamine antagonists are effective anti-emetics. Domperidone does not readily cross the blood-brain barrier and is less likely to cause central nervous system side-effects than metoclopramide. However, a direct comparison of the safety and efficacy of the two drugs has not hitherto been made. Ninety-five patients, with symptoms of nausea and vomiting due to a variety of oesophageal or gastric disorders, were recruited into a randomised, double-blind, three-part, parallel-group comparative study of controlled release metoclopramide 15 mg (Gastrobid Continus tablets, Napp Laboratories) given twice daily, and domperidone 10 mg or 20 mg given three times daily. Assessments for nausea, vomiting, reflux symptoms and adverse events were made on entry to the study. Patients were randomly allocated to one of the three treatment regimes for a period of seven days, throughout which daily symptomatology and use of escape medication were recorded on a diary card. At the end of the treatment period, nausea, vomiting and reflux symptoms, adverse events and a global assessment of patients' symptom control were recorded by the investigator. Both controlled release metoclopramide and high and low dose domperidone significantly reduced symptoms of belching, flatulence, distension, heartburn, regurgitation, reflux, nausea and vomiting compared to baseline. There were no significant differences between the three treatments in efficacy or in the number and severity of side-effects.

Delayed-Action Preparations↗
PubMed1990

Differential splicing generates a nervous system-specific form of Drosophila neuroglian.

We recently described the characterization and cloning of Drosophila neuroglian, a member of the immunoglobulin superfamily. Neuroglian contains six immunoglobulin-like domains and five fibronectin type III domains and shows strong sequence homology to the mouse neural cell adhesion molecule L1. Here we show that the neuroglian gene generates at least two different protein products by tissue-specific alternative splicing. The two protein forms differ in their cytoplasmic domains. The long form is restricted to the surface of neurons in the CNS and neurons and some support cells in the PNS; in contrast, the short form is expressed on a wide range of other cells and tissues. Thus, whereas the mouse L1 gene appears to encode only one protein that functions largely as a neural cell adhesion molecule, its Drosophila homolog, the neuroglian gene, encodes at least two protein forms that may play two different roles, one as a neural cell adhesion molecule and the other as a more general cell adhesion molecule involved in other tissues and imaginal disc morphogenesis.

Amino Acid Sequence↗
PubMed1990

Drosophila neurotactin, a surface glycoprotein with homology to serine esterases, is dynamically expressed during embryogenesis.

Drosophila neurotactin is a transmembrane glycoprotein with an apparent molecular mass of 135 x 10(3). Neurotactin is regionally expressed at the cellular blastoderm stage; later in embryogenesis the expression of the protein becomes restricted to cells of the peripheral and central nervous system. Immunocytochemical localization shows neurotactin protein at points of cell-cell contact. Using the anti-neurotactin monoclonal antibody BP-106, a neurotactin cDNA was isolated that encodes a 846 residue polypeptide. The chromosomal location of the neurotactin gene is 73C. The extracellular domain at the carboxyterminal end of the neurotactin protein shows a strong structural and sequence homology to serine esterases without retaining the amino acids forming the active center. Neurotactin therefore belongs to a growing group of proteins including Drosophila glutactin and thyroglobulins that are known to share this serine esterase protein domain motif without retaining the active center of the enzyme.

Amino Acid Sequence↗
PubMed1989

Drosophila neuroglian: a member of the immunoglobulin superfamily with extensive homology to the vertebrate neural adhesion molecule L1.

Drosophila neuroglian is an integral membrane glycoprotein that is expressed on a variety of cell types in the Drosophila embryo, including expression on a large subset of glial and neuronal cell bodies in the central and peripheral nervous systems and on the fasciculating axons that extend along them. Neuroglian cDNA clones were isolated by expression cloning. cDNA sequence analysis reveals that neuroglian is a member of the immunoglobulin superfamily. The extracellular portion of the protein consists of six immunoglobulin C2-type domains followed by five fibronectin type III domains. Neuroglian is closely related to the immunoglobulin-like vertebrate neural adhesion molecules and, among them, shows most extensive homology to mouse L1. Its homology to L1 and its embryonic localization suggest that neuroglian may play a role in neural and glial cell adhesion in the developing Drosophila embryo. We report here on the identification of a lethal mutation in the neuroglian gene.

Amino Acid Sequence↗
PubMed1989

Expression of engrailed proteins in arthropods, annelids, and chordates.

engrailed is a homeobox gene that has an important role in Drosophila segmentation. Genes homologous to engrailed have been identified in several other organisms. Here we describe a monoclonal antibody that recognizes a conserved epitope in the homeodomain of engrailed proteins of a number of different arthropods, annelids, and chordates; we use this antibody to isolate the grasshopper engrailed gene. In Drosophila embryos, the antibody reveals engrailed protein in the posterior portion of each segment during segmentation, and in a segmentally reiterated subset of neuronal cells during neurogenesis. Other arthropods, including grasshopper and two crustaceans, have similar patterns of engrailed expression. However, these patterns of expression are not shared by the annelids or chordates we examined. Our results provide the most comprehensive view that has been obtained of how expression patterns of a regulatory gene vary during evolution. On the basis of these patterns, we suggest that engrailed is a gene whose ancestral function was in neurogenesis and whose function was co-opted during the evolution of segmentation in the arthropods, but not in the annelids and chordates.

Amino Acid Sequence↗
PubMed1989

Lineage, migration, and morphogenesis of longitudinal glia in the Drosophila CNS as revealed by a molecular lineage marker.

Previous studies described three different classes of glial cells in the developing CNS of the early Drosophila embryo that prefigure and ensheath the major CNS axon tracts. Among these are 6 longitudinal glial cells on each side of each segment that overlie the longitudinal axon tracts. Here we use transformant lines carrying a P element containing a 130 bp sequence from the fushi tarazu gene in front of the lacZ reporter gene to direct beta-galactosidase expression in the longitudinal glia. Using this molecular lineage marker, we show that 1 of the "neuroblasts" in each hemisegment is actually a glioblast, which divides once symmetrically, in contrast to the typical asymmetric neuroblast divisions, producing 2 glial cells, which migrate medially and divide to generate the 6 longitudinal glial cells. As with neuroblasts, mutations in Notch and other neurogenic genes lead to supernumerary glioblasts. The results indicate that the glioblast is similar to other neuroblasts; however, the positionally specified fate of this blast cell is to generate a specific lineage of glia rather than a specific family of neurons.

Animals↗
PubMed1989

The role of segment polarity genes during Drosophila neurogenesis.

Segment polarity genes in Drosophila are required for the proper formation of epidermal pattern within each segment. Here we show that certain segment polarity genes are also critical for the determination of specific neuronal identities in the developing central nervous system (CNS) of the Drosophila embryo. For several mutants, however, the pattern defects do not simply parallel their cuticular phenotypes. In fused, armadillo, and cubitus interruptus Dominant mutants, much of the CNS appears relatively normal. In hedgehog mutants, the CNS is highly disorganized, but this disruption may occur secondary to the initial events of neurogenesis. The specific cellular defects in patched mutants suggests that this gene specifies a subset of neuroblasts and neural progeny underlying the region of epidermal pattern defect. gooseberry mutants display a complex series of alterations in neuronal identity both underlying and outside of the region of epidermal modification. Neuronal identities of a set of cells along the midline appear to be changed in Cell mutants. The phenotype of wingless mutants is the most restricted and may be due to improper communication between sibling neurons. Thus, in addition to their functions in epidermal pattern formation, at least four of the segment polarity genes (gooseberry, patched, Cell, and wingless) appear to have specific roles in the control of cell fates during neurogenesis.

Animals↗
PubMed1989

Expression of engrailed during segmentation in grasshopper and crayfish.

We have used a monoclonal antibody that recognizes engrailed proteins to compare the process of segmentation in grasshopper, crayfish, and Drosophila. Drosophila embryos rapidly generate metameres during an embryonic stage characterized by the absence of cell division. In contrast, many other arthropod embryos, such as those of more primitive insects and crustaceans, generate metameres gradually and sequentially, as cell proliferation causes caudal elongation. In all three organisms, the pattern of engrailed expression at the segmented germ band stage is similar, and the parasegments are the first metameres to form. Nevertheless, the way in which the engrailed pattern is generated differs and reflects the differences in how these organisms generate their metameres. These differences call into question what role homologues of the Drosophila pair-rule segmentation genes might play in other arthropods that generate metameres sequentially.

Animals↗
PubMed1987

Characterization and cloning of fasciclin III: a glycoprotein expressed on a subset of neurons and axon pathways in Drosophila.

To identify candidates for neuronal recognition molecules in Drosophila, we used monoclonal antibodies to search for surface glycoproteins expressed on subsets of axon bundles (or fascicles) during development. Here we report on the characterization and cloning of fasciclin III, which is expressed on a subset of neurons and axon pathways in the Drosophila embryo. Fasciclin III is also expressed at other times and places including transient segmentally repeated patches in the neuroepithelium and segmentally repeated stripes in the body epidermis. Antisera generated against each of four highly related forms of the protein were used for cDNA expression cloning to identify a single gene, which was confirmed to encode fasciclin III by tissue in situ hybridization and genetic deficiency analysis.

Animals↗
PubMed1987

On the molecular organization, diversity and functions of desmosomal proteins.

After a brief review of epithelial cell junctions, the authors describe a series of observations and experiments directed toward elucidating the molecular organization and functions of the proteins of desmosomes (maculae adherentes). Their immunofluorescence observations reveal differences between the proteins of junctional complex and other desmosomes of the same cells. Quantitative immuno-localization studies are described using protein A-colloidal gold markers and a series of monospecific, polyclonal antibodies directed against cytokeratins and four desmosomal protein families. It is shown that desmoplakin III (about 81 kDa) is restricted to the desmosomal cytoplasmic plaque, which possesses outer and inner dense zones. Desmoplakins I/II (about 240 kDa and 210 kDa) extend across the same range and beyond into the intermediate filament-rich cytoplasm. Two glycoprotein families, desmoglein I (DGI; about 150 kDa) and desmoglein II (DGII; about 97-118 kDa), extend from the desmosomal midline (or beyond) across the desmoglea (intercellular space), through the plasma membrane and across both layers of the plaque, terminating near its cytoplasmic border. Cytokeratins do not extend into the desmosome. With new procedures utilizing guanidine HCl for preparing and fractionating desmosomal proteins, DGII has been purified to homogeneity. DGII, DGI and a third protein are all shown to bind Ca2+, which is known to promote desmosome assembly.

Animals↗
PubMed1987

Neural-specific carbohydrate moiety shared by many surface glycoproteins in Drosophila and grasshopper embryos.

Antiserum against horseradish peroxidase (anti-HRP Ab) labels the surfaces of neurons in both Drosophila and grasshopper (Jan and Jan, 1982). Here we show that the anti-HRP Ab (1) immunoprecipitates at least 17 different membrane glycoproteins from the Drosophila embryo CNS (and a similar array from grasshopper), and (2) recognizes a neural-specific carbohydrate moiety expressed by most if not all of these proteins. Although the anti-HRP Ab stains all axon pathways, 2 of the anti-HRP glycoproteins, fasciclin I and II, are expressed on specific subsets of axon pathways in the grasshopper embryo.

Animals↗
PubMed1984

Immunological comparison of desmosomal components from several bovine tissues.

A panel of monoclonal antibodies and conventional antisera directed against desmosomal proteins from bovine muzzle epidermis was used to identify immunologically related proteins from two other bovine stratified squamous epithelia, cornea and esophagus. Desmosome-enriched tissue fractions were prepared from epidermis, cornea, and esophagus. These tissue extracts were electrophoresed on sodium dodecyl sulfate (SDS)-polyacrylamide gels, blotted onto nitrocellulose paper, and labeled using an indirect immunoperoxidase technique. Labeling with the conventional antisera demonstrates that each of the previously characterized epidermal desmosomal proteins or protein families has an immunologically cross-reacting counterpart in cornea and esophagus. However, chemical differences between homologous desmosomal proteins in these three tissues have also been detected. The corresponding proteins in the different tissues have similar but not always identical apparent molecular weights. Moreover, tissue-restricted antigenic determinants were detected in two of the desmosomal proteins families using four monoclonal antibodies, each of which recognizes a distinct antigenic determinant.

Animals↗
PubMed1981

Chicken fetal antigen (CFA) expression on the primitive erythroid maturation series.

Indirect immunofluorescence was utilized to study the expression of chicken fetal antigens (CFA), developmentally phasic membrane antigens, on the primitive erythroid series during chick embryo development. Cells of this series expressed CFA determinants at all four stages of cellular maturation. However, the relative intensity of fluorescent staining (measurement of CFA determinants) varied with development. CFA determinant loss was correlated with the age of the embryo, and the stage of cellular maturation. Indirect immunofluorescence utilizing antisera capable of detecting eight individual CFA determinants revealed that all eight CFA determinants were present on early polychromatic erythrocytes of the primitive series, but that a selective and sequential loss of CFA determinants occurred in later stages. The data suggest that certain CFA determinants are differentially expressed during primitive erythroid cellular maturation in the developing chick embryo.

Animals↗
PubMed1980

Chicken fetal antigen expression on the definitive erythroid maturation series in the bone marrow of the adult chicken.

Chicken fetal antigen (CFA) describes a membrane developmental antigen system present on embryonic and fetal erythroid cells that is present during development, but is absent on erythrocytes of mature chickens. In this study, CFA was detected by indirect immunofluorescence and correlated with six stages of morphological maturation of erythroid cells. All cells in the erythroid series through the late polychromatic erythrocyte (reticulocyte) stage were found to possess CFA. Fluorescent intensity and staining patterns of the definitive erythroid series demonstrated CFA concentration increase and distribution pattern change throughout erythroid maturation.

Anemia↗
PubMedDate not supplied

Endovascular management of acute extensive iliofemoral deep venous thrombosis caused by May-Thurner syndrome.

PURPOSE: The authors report their experience on the treatment of acute extensive iliofemoral deep venous thrombosis (DVT) due to May-Thurner syndrome using endovascular techniques. MATERIALS AND METHODS: During a 1-year period, 10 symptomatic women (age range, 22-52 years; mean, 35.5 years) were referred for treatment. After ascending venography, an infusion catheter system was placed and urokinase was infused locally into the thrombus burden. After near complete clot dissolution (> or = 95%) or lytic stagnation, the residual left common iliac vein narrowing was treated by means of angioplasty and/or placement of Wallstent endoprosthesis. All patients continued to receive oral warfarin. Patients were followed-up by means of clinic visits, and stent patency was assessed by means of duplex Doppler sonography performed at 1, 3, 6, and 12 months, and then yearly thereafter. RESULTS: The total dose of urokinase used and the duration of infusion were 5.87 +/- 2.57 million units (range, 3.18-10.7) and 51.95 +/- 21.57 hours (range, 26.5-89), respectively. After completion of thrombolytic therapy, the iliac vein narrowing was successfully treated by deployment of a Wallstent endoprosthesis in all 10 patients because of failure of angioplasty. No major bleeding complications occurred. Initial clinical success was 100%, with complete resolution of symptoms in all patients. One patient, who was hypercoagulable and was receiving chemotherapy for metastatic adenocarcinoma, had recurrent symptomatic acute DVT 1 month after therapy. She underwent successful repeated lysis. The remaining nine patients were asymptomatic, with a mean follow-up of 15.2 months (range, 6-36 months). One asymptomatic patient, at 36-month follow-up ultrasound, had iliac vein occlusion and well-developed venous collaterals. Serial ultrasonography in all 10 patients showed no evidence of valvular insufficiency in the femoral and popliteal veins. CONCLUSION: Catheter-directed thrombolytic therapy for the treatment of acute extensive iliofemoral DVT due to May-Thurner syndrome is an effective method for restoring venous patency and provides relief of the acute symptoms. The underlying left common iliac vein lesion invariably needs to undergo stent placement.

Adult↗