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R Usha

Publications and source records attributed to R Usha.

At least 37 records · Page 2Linked to original sources
PubMed1993

Expression of an animal virus antigenic site on the surface of a plant virus particle.

To investigate if cowpea mosaic virus (CPMV) particles can be used to express foreign protein sequences, oligonucleotides encoding an epitope derived from VP1 of foot-and-mouth disease virus (FMDV) were cloned into the region of the CPMV genome encoding the small (S) coat protein. The chimeras were designed so that the foreign sequence was expressed either as an insertion or as a replacement for part of the wild-type sequence. While RNA from both chimeras was able to replicate in cowpea protoplasts only the construct containing the FMDV sequence as an insertion was able to direct capsid formation and infect whole cowpea plants. The modified S protein produced in plants infected with the insertion derivative reacted with FMDV-specific antiserum. These results show that CPMV can be used as an antigen presentation system and raises the possibility of producing vaccines in plants using a RNA virus-based vector.

Amino Acid Sequence↗
PubMed1992

Late diagnosis of phenylketonuria in a Bedouin mother.

We report on the first case of phenylketonuria in a Bedouin woman with 3 children having the phenylketonuria embryofetopathy. Herein, we discuss briefly hazards of late diagnosis of maternal phenylketonuria.

Abortion, Habitual↗
PubMed1992

Arginine residues involved in binding of tetrahydrofolate to sheep liver serine hydroxymethyltransferase.

The arginine residue(s) necessary for tetrahydrofolate binding to sheep liver serine hydroxymethyltransferase were located by phenylglyoxal modification. The incorporation of [7-14C]phenylglyoxal indicated that 2 arginine residues were modified per subunit of the enzyme and the modification of these residues was prevented by tetrahydrofolate. In order to locate the sites of phenylglyoxal modification, the enzyme was reacted in the presence and absence of tetrahydrofolate using unlabeled and radioactive phenylglyoxal, respectively. The labeled phenylglyoxal-treated enzyme was digested with trypsin, and the radiolabeled peptides were purified by high-performance liquid chromatography on reversed-phase columns. Sequencing the tryptic peptides indicated that Arg-269 and Arg-462 were the sites of phenylglyoxal modification. Neither a spectrally discernible 495-nm intermediate (characteristic of the native enzyme when substrates are added) nor its enhancement by the addition of tetrahydrofolate, was observed with the phenylglyoxal-modified enzyme. There was no enhancement of the rate of the exchange of the alpha-proton of glycine upon addition of tetrahydrofolate to the modified enzyme as was observed with the native enzyme. These results demonstrate the requirement of specific arginine residues for the interaction of tetrahydrofolate with sheep liver serine hydroxymethyltransferase.

Amino Acid Sequence↗
PubMed1992

Partial amino acid sequence of sheep liver serine hydroxymethyltransferase and comparison of peptide maps of the enzyme from human, ox livers and Escherichia coli.

A comparison of the tryptic peptide maps of serine hydroxymethyltransferase from sheep, human, ox livers and Escherichia coli revealed that the mammalian enzymes were similar, while the bacterial enzyme exhibited differences in the primary structure. N-terminus of the reduced carboxymethylated sheep liver enzyme was acetylated. Serine hydroxymethyltransferase was hydrolyzed with trypsin and fragments of peptides were separated by high performance liquid chromatography using a combination of gel permeation, reverse phase and ion-pair chromatography. The peptides were sequenced manually using the 4-N,N'-dimethyl aminoazobenzene-4'-isothiocyanate/phenyl isothiocyanate double coupling method. The tryptic peptides with 80% homology or above were aligned on the rabbit liver enzyme sequence.

Amino Acid Sequence↗
PubMed1991

Altered fetal growth: antenatal diagnosis by symphysis-fundal height in India and comparison with western charts.

Antenatal identification of altered fetal growth is a significant problem in spite of the availability of sophisticated technology. The present study was undertaken to generate symphysis-fundal height curves locally for an Indian population and to assess their value in predicting altered fetal growth. The measurements were found to have a high sensitivity of 80.8% and specificity of 93.5% in detection of small for date babies and a sensitivity and specificity of 72.2% and 95.2%, respectively in detection of fetal macrosomia. The locally generated symphysis-fundal height charts have been compared with the western charts and the differences stressed. It is concluded that symphysis-fundal height curves should be locally generated for best results.

Anthropometry↗
PubMed1990

Host cell selection of Murray Valley encephalitis virus variants altered at an RGD sequence in the envelope protein and in mouse virulence.

We have passaged the prototype strain of Murray Valley encephalitis virus in SW13 (human) cells, sequenced the E and M genes, and examined the virulence of the passaged virus for 21-day-old mice following intracranial and intraperitoneal inoculation. Six independent passage series were carried out: four in the presence of mouse hyperimmune ascitic fluid and two without antibody. Changes were observed in the E protein deduced amino acid sequence for each of the six 10th passage stocks sequenced. Eleven changes were observed in total for the six stocks sequenced; these were at residues 117, 118, 390, 423, and 460. Nine of the changes were nonconservative. Five of the six passaged variants were altered at Asp 390 which is part of an Arg-Gly-Asp (RGD) sequence. This change resulted from adaptation to SW13 cells rather than from antibody selection. The RGD sequence (and residue 423) falls within a region which is highly conserved between flaviviruses and is strongly hydrophilic. All five variants which were altered at Asp 390 were attenuated in 21-day-old mice following i.p. inoculation. We propose that the domain of E encompassing the RGD sequence is an important determinant of flavivirus pathogenicity.

Adenocarcinoma↗
PubMed1990

Phenotypic variability in Meckel-Gruber syndrome.

Five Bedouin sibs are described with Meckel-Gruber syndrome (MGS), an autosomal recessive disorder with multiple abnormalities. Each affected sib manifested only two of the three cardinal signs of MGS: occipital encephalocele and polycystic kidneys, lacking polydactyly. The phenotypic variability of the MGS pleiotropic gene is briefly discussed.

Chromosome Aberrations↗
PubMed1990

Management of cyclical menorrhagia with prostaglandin synthetase inhibitor.

A well controlled double blind prospective trial was undertaken to determine the efficacy of mefenamic acid in the treatment of menorrhagia. Eighty patients who had unexplained cyclical menorrhagia with secretory endometrium received mefenamic acid orally in a dose of 500 mg 8 hourly or a placebo tablet thrice daily starting from day-one of the cycle for 5 days or till cessation of menses. Mefenamic acid administration caused a statistically significant reduction in the number of days of bleeding from 9.7 +/- 3.1 days before treatment to 4.1 +/- 0.6 days after treatment. It also brought about significant reduction in the amount of bleeding in terms of number of pads used per day, that is from 15.2 +/- 3.1 before treatment to 6.5 +/- 0.02 after treatment. Eighty-six percent patients in the treatment group had control of menorrhagia with the drug compared to 20% in the control group without drugs and this difference was statistically significant. Mefenamic acid proved to be a potent and efficacious agent in the control of unexplained menorrhagia.

Adult↗
PubMed1990

Primary pure choriocarcinoma of the ovary.

The authors report a case of pure primary choriocarcinoma of the ovary (FIGO stage III A) in a young patient with 24-month follow-up. The patient, an advanced case of choriocarcinoma, was treated with combination chemotherapy comprising vincristine, bleomycin and cisplatinum. It is stressed that at that stage of the disease it is of prime importance to initiate combination chemotherapy for improvement in survival and prognosis of such cases rather than to distinguish the gestational or nongestational origin of the tumor.

Adult↗
PubMed1990

Prevalence of diabetes, hypertension and renal disease amongst railway workers in Malaysia.

A survey was done to determine the prevalence of diabetes mellitus, hypertension and renal disease, as well as extent of diabetic control, amongst the workers of Malaysian Railways. The prevalence of diabetes was high at 6.6%, with 3.8% of these being insulin dependent diabetes. The highest prevalence was in Indians (16.0%) followed by Chinese (4.9%) and Malays (3.0%). Using HbA1 measurements, diabetic control was poor in 70.6% of the diabetics. Hypertension was found in 37% and proteinuria in 35%. Renal impairment was present in 30% of the diabetics. This survey shows that diabetes, hypertension and renal disease are high amongst the railway workers in Malaysia.

Adult↗
PubMed1987

A family with spondyloepimetaphyseal dwarfism: a 'new' dysplasia or Kniest disease with autosomal recessive inheritance?

We present an Arab family with some features of Kniest disease. The proband was a six year old boy with rhizomelic short limbed dwarfism, 'dish-like' facies, cleft palate, deafness, and camptodactyly. Most radiological changes were compatible with Kniest disease. Two younger sibs, similarly affected, had died at a few months old, and the pedigree shows strong evidence of autosomal recessive inheritance, unlike previously reported cases of Kniest disease which have shown autosomal dominant inheritance.

Abnormalities, Multiple↗
PubMed1986

Interstitial deletion of the long arm of chromosome 1 [del(1)(q32q42)].

A severely malformed girl died 7 days after birth and was found to have de novo interstitial deletion of 1q (1q32----1q42). Clinical abnormalities included microcephaly, encephalocele, small eyes with unilateral esotropia, hypertelorism but small prominent nose, highly arched palate, micrognathia, abnormal cry, apparently abnormal low-set ears, short neck with low posterior hair line, narrow shoulders, congenital heart defect, hypoplastic nails, overlap of toes with flat feet, and single umbilical artery.

Abnormalities, Multiple↗
PubMed1986

Protein structural homology: a metric approach.

The flexibility of the polypeptide fold of proteins is essentially due to the rotational freedom about the main chain bonds involving C alpha atoms. The polypeptide fold can therefore be represented by virtual bonds joining consecutive C alpha atoms. The ordered sequence of virtual torsion and bond angles involving these bonds can be used to specify the fold. Such representations can then be compared to reveal structural similarities using the Needleman & Wünsch algorithm, which has been developed for comparison of amino acid sequences. Such an approach is presented and illustrated with examples. The method is suitable for detecting structural similarities that extend over 7 or more residues.

Hemoglobins↗