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N Rao

Publications and source records attributed to N Rao.

At least 73 records · Page 4Linked to original sources
PubMed1994

Molecular mapping of the Cromer blood group Cra and Tca epitopes of decay accelerating factor: toward the use of recombinant antigens in immunohematology.

Cromer blood group antigens reside on the complement regulatory protein decay accelerating factor (DAF, CD55). This glycosyl-phosphatidylinositol-anchored glycoprotein is widely distributed, especially among cell types in contact with plasma. Numerous Cromer blood group antigens have been defined using alloantibodies induced by transfusion or pregnancy. However, few pairs of antithetical antigens have been described in this system, presumably because of the rarity of the low-frequency alleles. Analysis of polymerase chain reaction-amplified genomic DNA showed that the Cr(a-) phenotype has a Ala193-->Pro substitution in short consensus repeat 4 (SCR4) of DAF, and the Tc(a-b+) phenotype has a Arg18-->Leu substitution in SCR1 of DAF. The locations of Cra and Tca epitopes were confirmed by analysis of Chinese hamster ovary cell transfectants expressing a Cr(a-) allele-specific transfectant and a chimeric protein containing only SCR1 of DAF, respectively. Overall, these studies further show the usefulness of an approach based on recombinant proteins in mapping blood group antigen epitopes and identifying blood group antibodies.

Antigens, CD↗
PubMed1994

Presenting characteristics of trisomy 8 as the primary cytogenetic abnormality associated with childhood acute lymphoblastic leukemia. A Pediatric Oncology Group (POG) Study (8600/8493).

Although trisomy 8 is the single most common numerical abnormality in acute myeloid leukemia (AML), relatively few cases with acute lymphoblastic leukemia (ALL) and trisomy 8 have been reported. We report the clinical and laboratory features of seven children with ALL and trisomy 8 as the sole cytogenetic abnormality and review nine similar cases from the literature. Among the children studied by the Pediatric Oncology Group (POG) with newly diagnosed ALL, only 0.3% had trisomy 8 as the sole abnormality. Four of our patients had T-cell ALL and three had early pre-B ALL. Presenting clinical features were typical for the respective immunophenotypes. Six of the seven children achieved complete remission. Our study suggest that trisomy 8 is an infrequent, recurring abnormality among children with ALL, which appears to be associated with a T-cell immunophenotype.

Adolescent↗
PubMed1994

Schistosoma mansoni: fractionation and characterization of the glycocalyx and glycogen-like material from cercariae.

The glycocalyx (GCX) that covers schistosomal cercariae is a complex molecule that has immunomodulating properties. Here, we purified milligram amounts of GCX using Anguilla lectin which binds to the GCX covering the cercarial body and tail. Typically, 10 million cercariae were extracted with phenol, dialyzed, and chromatographed on a Sepharose 2B-CL column. An average of 39 mg of total carbohydrate eluted near the void volume from which 31 mg of glycogen-like material was further separated by lectin affinity chromatography. Its identity was established by compositional analysis, sensitivity to amylase digestion, and its nuclear magnetic resonance spectrum. The lectin-bound GCX was eluted with 0.1 M fucose with a final yield of 5.3 mg carbohydrate. Fucose composed 40% of the total GCX carbohydrate with lesser but approximately equal amounts of galactose, glucosamine, and galactosamine present. NMR data indicated that the amino sugars were N-acetylated. Glucose was also present but in varying amounts in different preparations of GCX. Oligosaccharides were released from GCX by hydrazinolysis and separated by electrophoresis after reductive amination to 8-aminonaphthalene-1,3,6-trisulfonic acid (ANTS). Bands comigrating with standards containing 11, 12, 16, and 17 sugar residues were detected. Thus, the GCX is a complex structure composed of oligosaccharides, probably linked to a peptide.

Amino Sugars↗
PubMed1994

Conjugated deferoxamine reduces blood-brain barrier disruption in experimental optic neuritis.

The purpose of this paper was to investigate the role of deferoxamine (DFO) scavenging of hydroxyl radical (.OH) on disruption of the blood-brain barrier (BBB) and demyelination in experimental optic neuritis. Eighteen strain-13 guinea pigs were sensitized for experimental allergic encephalomyelitis. Nine animals received 100 mg/kg of hydroxyethyl starch-conjugated (HES) DFO by daily intraperitoneal injection commencing the day of antigenic sensitization. Nine paired litter mates received daily IP injections of HES. Serial fat-suppressed magnetic resonance imaging of the optic nerves was obtained with a T2 weighting (T2w) to evaluate demyelination and after intravascular administration of Gd-DTPA to evaluate BBB disruption. The intensity of Gd-DTPA enhancement and T2w signal of the optic nerves was quantitated 3, 7, 10 and 14 days after antigenic sensitization. Animals were then sacrificed and the optic nerves processed for light and transmission electron microscopy with ultracytochemical localization of endogenous hydrogen peroxide (H2O2) and immunogold colocalization of extravasated serum albumin. The area of the optic nerve head, intensity of toluidine blue staining, and the cellular infiltrate were digitized and quantitated. Administration of HES-DFO significantly reduced the intensity of Gd-DTPA enhancement in the optic nerves of HES-DFO-treated animals compared to paired control HES animals (p = 0.0236), with the mean difference between control and treated animals of 19.39. The difference in T2w signal was not significant (p = 0.39), with a mean difference between control and treated animals of -5.51. The intensity of toluidine blue staining of optic nerve specimens was slightly less with HES-DFO compared to untreated animals (mean pair difference 2.48), and the inflammatory infiltrate was reduced with HES-DFO compared to untreated animals (mean pair difference = 61.57); these differences were not statistically significant. In the optic nerve specimens of both groups cerium perhydroxide-derived H2O2 reaction product was evident in a predominantly perivascular and perineural distribution. Immunogold-labeled serum albumin showed extravasation at foci of perivascular inflammation in both the presence and absence of H2O2-derived reaction product. Conjugated DFO reduces disruption of the BBB, as measured by Gd-DTPA enhancement, suggesting the .OH radical generated from perivascular H2O2 may play a role in alterations of vascular permeability in experimental optic neuritis.

Animals↗
PubMed1994

Recent advances in immunohematology.

Knowledge of the biochemistry and genetics of erythrocyte blood group antigens has been growing rapidly over the past several years. Last year, the molecular basis for the major Rh blood group antigens was delineated. In addition, the genetic and biochemical bases of several other blood group antigens were identified. One of the most interesting matches of blood group antigens to a functional membrane protein was that of the Diego antigens to the erythrocyte anion channel (band 3) protein. In addition, knowledge of the molecular basis of blood group antigens is now leading rapidly to the usefulness of molecular techniques in identifying blood group genotypes and even blood group antibody specificities. This knowledge has also broadened our understanding of the pathogenesis of erythrocyte disorders associated with null blood group phenotypes. The diagnosis and treatment of autoimmune hemolytic anemia has seen slow but steady progress. New techniques appear promising as methods for distinguishing clinically important from benign autoantibodies. The molecular targets for erythrocyte autoantibodies were also largely identified. Treatment of autoimmune hemolytic anemia is also slowly being improved with the use of agents such as intravenous gammaglobulin, danazol, and immunosuppressive agents, all of which have also been important in the treatment of autoimmune thrombocytopenic purpura.

Anemia, Hemolytic, Autoimmune↗
PubMed1993

Structure and biological activities of a heparin-derived hexasaccharide with high affinity for basic fibroblast growth factor.

We demonstrated previously that heparin-derived hexasaccharides are the smallest fragments of the polysaccharide with comparable basic fibroblast growth factor (bFGF)-modulating activity in vitro (Ishihara, M., Tyrrell, D.J., Stauber, G.B., Brown, S., Cousens, L., and Stack, R.J. (1993) J. Biol. Chem. 268, 4675-4683. In this report, a specific hexasaccharide having high affinity for recombinant human bFGF was isolated and its structure deduced by analysis of its reduced disaccharide products after treatment with nitrous acid at pH 1.5, and by 1H NMR spectroscopy. The hexasaccharide has the structure [IdoA(2-OSO3)alpha 1-4GlcNSO3(6-OSO3)alpha 1-4]2IdoA(2-OSO3)alpha 1-4 AManR(6-OSO3). The hexasaccharide effectively inhibits the binding of syndecan-transfected RO-12 UC cells to bFGF-coated wells (Ishihara, M., Tyrrell, D.J., Kiefer, M.C., Barr, P.J., and Swiedler, S.J. (1992) Anal. Biochem. 202, 310-315), prevents the binding of 125I-bFGF to confluent monolayers of adrenocortical endothelial (ACE) cells, and inhibits the bFGF-dependent proliferation of ACE cells. Unlike the heparin from which it was derived, however, the hexasaccharide cannot promote the binding of 125I-bFGF to a recombinant high affinity bFGF receptor (flg) or restore the bFGF-dependent proliferative response to ACE cells grown in the presence of 5 mM sodium chlorate. Collectively, these data indicate that a hexasaccharide can be as effective as heparin as an antagonist of bFGF-mediated cell mitogenesis.

Animals↗
PubMed1993

Human erythrocyte acetylcholinesterase bears the Yta blood group antigen and is reduced or absent in the Yt(a-b-) phenotype.

The Cartwright (Yt) blood group antigens have previously been shown likely to reside on a phosphatidylinositol-linked erythrocyte membrane protein. In this study, an unusual individual whose red blood cells (RBCs) were of the previously unreported Yt(a-b-) phenotype were used, along with normal Yt(a+) cells, to investigate serologically and biochemically the relationship of the Yta antigen to known phosphatidylinositol-linked erythrocyte proteins. Yt(a-b-) RBCs expressed normal amounts of various phosphatidyl-inositol-linked proteins except acetylcholinesterase. Further, human anti-Yta reacted with acetylcholinesterase in immunoprecipitation and immunoblotting studies. Thus, acetylcholinesterase is now identified as the protein bearing the Yt blood group antigens.

Acetylcholinesterase↗
PubMed1993

Developing a Chinese version of the psychoeducational profile (CPEP) to assess autistic children in Hong Kong.

The Psychoeducational Profile (PEP) has been used to assess the developmental functioning and behavior of autistic children in the West. To examine its suitability for assessing autistic children in Hong Kong, the PEP was translated into Chinese and certain items were adapted for local conditions. The Chinese version of the PEP (CPEP) was administered to 23 autistic children and 40 children with normal development, ranging in age from 3 to 7 years. Some of the children were also given the Merrill-Palmer Scale of Mental Tests. Results indicated that CPEP scores correlated significantly with Merrill Palmer scores, demonstrating criterion-related validity. Significant positive correlations were also found between age and CPEP scores for children with normal development, verifying that the CPEP has properties of a developmental scale. There was also a significant difference between children with normal development and children with autism on the Pathology scale, suggesting that the scale has discriminant validity.

Autistic Disorder↗
PubMed1993

Trabeculectomy and Molteno implantation for glaucomas associated with uveitis.

PURPOSE: This study compares the outcomes of trabeculectomy and Molteno implantation in the treatment of glaucomas associated with uveitis. METHODS: Forty-five patients with uveitis, who had undergone filtering surgery for glaucomas associated with uveitis, were reviewed retrospectively. Successful outcome was defined as final intraocular pressure (IOP) of 6 to 21 mmHg, with a minimum follow-up of 6 months without visually devastating complications or loss of light perception. RESULTS: One- and two-year life-table success rates, respectively, were 81% and 73% with trabeculectomy (16 patients); 53% and 31% with combined trabeculectomy and first-stage (reserve) Molteno implantation (19 patients); and 79% and 79% with one-stage Molteno implantation (10 patients). In 11 patients who underwent second-stage Molteno implantation after trabeculectomy failure, 1- and 2-year life-table success rates were 79% and 79%, respectively. Complications included surgically treated choroidal effusions (1/45; 2%), choroidal hemorrhages (3/45; 7%), and chronic hypotony (3/45; 7%). Follow-up in all groups ranged from 5 to 70 months (mean +/- standard deviation, 28 +/- 17 months). CONCLUSIONS: Trabeculectomy provides surprisingly good results in glaucomas associated with uveitis (modulation of wound healing with antimetabolites probably would afford an even higher success rate). However, when significant, immediate postoperative and/or moderate chronic postoperative inflammation is likely, aqueous drainage devices appear more likely to control IOP.

Adult↗
PubMed1993

Two novel pathogenic mitochondrial DNA mutations affecting organelle number and protein synthesis. Is the tRNA(Leu(UUR)) gene an etiologic hot spot?

We identified two patients with pathogenic single nucleotide changes in two different mitochondrial tRNA genes: the first mutation in the tRNA(Asn) gene, and the ninth known mutation in the tRNA(Leu(UUR)) gene. The mutation in tRNA(Asn) was associated with isolated ophthalmoplegia, whereas the mutation in tRNA(Leu(UUR)) caused a neurological syndrome resembling MERRF (myoclonus epilepsy and ragged-red fibers) plus optic neuropathy, retinopathy, and diabetes. Both mutations were heteroplasmic, with higher percentages of mutant mtDNA in affected tissues, and undetectable levels in maternal relatives. Analysis of single muscle fibers indicated that morphological and biochemical alterations appeared only when the proportions of mutant mtDNA exceeded 90% of the total cellular mtDNA pool. The high incidence of mutations in the tRNA(Leu(UUR)) gene suggests that this region is an "etiologic hot spot" in mitochondrial disease.

Adult↗
PubMed1993

Differential S100 beta expression in choroidal and skin melanomas: quantitation by the polymerase chain reaction.

PURPOSE: S100 beta, a member of a calcium-binding protein family (S100s), is an important clinical marker for skin melanoma. In contrast, uveal melanomas appeared to express S100 beta protein less frequently and to a lesser degree. This study was performed to verify and extend this finding to the mRNA level. METHODS: A quantitative polymerase chain reaction (PCR)-based method was used. A ratio, comparing the S100 beta PCR fragment to that of beta-actin (an internal reference gene), was generated to compare S100 beta mRNA expression among samples. RESULTS: The ratios for skin melanomas (1.2 to 3.9; three tissues and two cell lines) were significantly higher than that for choroidal melanomas (0.1 to 0.63; seven of eight primary tumors and four of four cell lines). Only one choroidal melanoma biopsy had a ratio greater than 1. The PCR products from choroidal melanoma were identical in size and sequence to the S100 beta, as determined by gel electrophoresis and RNA conformational polymorphism. Because the ratios were also low in choroidal melanoma cell lines, the S100 beta phenotype appears to be genetically stable. CONCLUSION: S100 beta is differentially expressed at the RNA and protein levels by skin and choroidal melanomas, which are derived from distinct populations of melanocytes. However, choroidal melanomas expressing little or no S100 beta were significantly stained by antiserum specific for the S100 protein family. Taken together, these data suggest that choroidal melanocytes express another, perhaps even novel, S100 protein(s).

Actins↗
PubMed1992

45,X/46,X,+r(X) can have a distinct phenotype different from Ullrich-Turner syndrome.

We present a patient with 45,X/46,X,+r(X) mosaicism and lack of inactivation of either the normal or the ring X in the 46,X,+r(X) cells. The patient has mental retardation, syndactyly, minor facial anomalies, and a congenital heart defect. Although most patients with 45,X/46,X,+r(X) have the Ullrich-Turner syndrome, 2 previously described patients with this karyotype also had a distinct phenotype consisting of severe mental retardation, syndactyly, and abnormal face. The unusually severe phenotype in these patients was thought to be due to lack of X-inactivation of the ring X chromosome. The findings in our patient support this hypothesis.

Adult↗
PubMed1992

Sex-differences in the disposition of substituted benzamides: pharmacokinetics of a gastroprokinetic agent (4-amino-5-chloro-2-[2- (methylsulfinyl) ethoxy]-N-[2-(diethylamino)ethyl] benzamide hydrochloride) (ML-1035) in male and female New Zealand white rabbits.

The disposition of 4-amino-5-chloro-2-[2-(methylsulfinyl)ethoxy]-N- [2-(diethylamino)ethyl] benzamide hydrochloride (ML-1035) following intravenous (10 mg kg-1) and oral (200 mg kg-1) dosing was investigated in male and female New Zealand white rabbits. After intravenous dosing ML-1035 was eliminated with a half-life of 1.45 +/- 0.49 h in males and 0.79 +/- 0.08 h in females. Volume of distribution at steady-state was 2.08 +/- 0.98 l kg-1 in males and 9.11 +/- 5.86 l kg-1 in females. Clearance averaged 2.99 +/- 1.11 l h-1 kg-1 in males and 16.73 +/- 7.29 l h-1 kg-1 in females. All pharmacokinetic parameters were significantly different between males and females (p < 0.05). Absolute bioavailability after oral administration was 7.35 per cent for males and 12.31 per cent for females, suggesting that ML-1035 undergoes significant first-pass elimination. Plasma area under the curve for the metabolites of ML-1035 after both oral and intravenous administration were also different between the two sexes. These data suggest that the disposition of ML-1035 shows significant differences between male and female rabbits.

Administration, Oral↗
PubMed1992

Molecular cytogenetic analysis of a familial 8p23.1 deletion associated with minimal dysmorphic features, seizures, and mild mental retardation.

We report a family in which three members presented with minimal phenotypic abnormalities, normal intelligence to mild mental retardation, and a cytogenetically terminal chromosome deletion at band 8p23.1 Whole chromosomal painting with a chromosome 8-specific DNA library confirmed this familial chromosome abnormality as a deletion, while fluorescence in situ hybridization with telomeric probes demonstrated the presence of telomeres at the deletion site. Coagulation studies were additionally performed to evaluate the purported location of the coagulation factor VII regulator gene at 8p23.1. A review of the clinical findings of seven cases of del(8)(p23.1) is presented.

Adult↗
PubMed1992

The teacher's role in facilitating memory and study strategy development in the elementary school classroom.

The efforts of 69 elementary school teachers to instruct children in cognitive processing activities were observed. Although the teaching of such activities was relatively infrequent, it varied by grade (occurring more often in grades 2-3 than in higher or lower grades) and by the content of instruction. Teachers of grade 4 and above more often provided rationales for the use of cognitive strategies than did teachers of younger children. In a second study, children of three achievement levels were selected from classrooms in which teachers varied in their use of suggestions regarding cognitive processes. Subsequent to training in the use of a memory strategy, children's performance on a maintenance trial was evaluated: Among average and low achievers, those whose teachers were relatively high in strategy suggestions showed better maintenance and more deliberate use of the trained strategy than did children whose teachers rarely made strategy suggestions. The role of school experience in the development of children's memory skills is discussed.

Achievement↗