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Biomedical subjects

P Roy

Publications and source records attributed to P Roy.

At least 361 records · Page 20Linked to original sources
PubMed1986

The virgin, modified, human, umbilical vein graft: morphologic characteristics and mechanical properties.

The authors used macrophotography, endoscopy, roentgenography, light microscopy, and transmission and scanning electron microscopy to assess the morphologic characteristics of 37 virgin, human, umbilical vein grafts. The specimens showed deep longitudinal folds (22%) and multiple transverse folds of the intimal surface (27%), irregularity of wall thickness (41%) and intimal breakdown exposing thrombogenic layers of the vein wall to blood (19%). The mechanical properties also studied were dynamic compliance, Young's modulus, breaking strength and breaking strain. The mean dynamic compliance was 6.44 X 10(-4) mm Hg-1 (SD = 2.02 X 10(-4) mm Hg-1, i.e., 31%), which is in agreement with results of others. The specimens showed great variability in Young's modulus, breaking strength and breaking strain. The structural deficiencies and variable mechanical properties of human umbilical vein grafts require investigation to determine their effect on patency rates due to increased thrombogenicity and thus to establish whether there are potential hazards associated with their use.

Biomechanical Phenomena↗
PubMed1985

The complete sequence of bluetongue virus serotype 10 segment 3 and its predicted VP3 polypeptide compared with those of BTV serotype 17.

The complete sequence of the large RNA segment 3 (L3) of bluetongue virus serotype 10 (BTV-10) has been determined from DNA copies of the viral RNA cloned in the E. coli plasmid pBR322. The L3 viral RNA is 2772 nucleotides long with a single open reading frame of 2706 nucleotides. The L3 predicted primary gene product (VP3) is 103 342 daltons and has a net charge at neutral pH of -5. The sequence of the L3 RNA species differs by 126 point mutations from that of BTV-17 (i.e., 95.5% homology; see M. Purdy, J. Petre and P. Roy, J. Virol. 51, 754-759, 1984). The predicted L3 primary gene products of the two viruses differ by 9 amino acids. These differences correspond to 9 point mutations and represent 0.15% of the sites where nucleotide substitution could cause an amino acid change. By contrast, another 114 point mutations in the genome correspond to 6.5% of the available sites where nucleotide substitutions could be silent (i.e., where a nucleotide substitution may not cause an amino acid change). Three point mutations are in the 3' non-coding region of the RNA species. The quantitative differences between the coding and silent mutations are interpreted as representing the result of gene product conservation.

Amino Acid Sequence↗
PubMed1985

Oral interaction in cooperative learning groups: speaking, listening, and the nature of statements made by high-, medium-, and low-achieving students.

Oral interaction within cooperative learning groups was observed for high-, medium-, and low-achieving students. Initially, cooperative and individualistic learning situations were compared on achievement and attitudes. Forty-eight 4th-grade American students were assigned to learning situations on a stratified random basis controlling for ability and sex. They participated in the study for 55 min a day for 15 instructional days. Two observation schemes were used. The results for the cooperative situation were factor analyzed to determine the basic dimensions of oral interaction within cooperative learning groups. Five orthogonal factors were identified: Exchanging Task-Related Information, Elaborating on the Information, Encouraging Each Other to Learn, Disagreeing With Each Other's Conclusions, and Making Nontask Comments and Sharing Personal Feelings. The oral participation of students from different achievement levels was differentially related to achievement. Vocalizing was found to be more strongly related to achievement than was listening to other group members vocalize. Medium and low achievers especially benefited from cooperative learning experiences.

Achievement↗
PubMed1985

A genetic probe for identifying bluetongue virus infections in vivo and in vitro.

We have used a DNA copy of segment 3 RNA of bluetongue virus serotype 17 (BTV-17) to detect sequence homology among the equivalent segments of five U.S.A. BTV serotypes (BTV-2, BTV-10, BTV-11, BTV-13 and BTV-17) as well as 14 other BTVs isolated from different endemic areas of the world. Both by in situ and Northern hybridization all the BTV serotypes were found to have RNA that reacted with the DNA probe. No homology was detected with epizootic haemorrhagic disease virus serotype 1, a related orbivirus. The BTV-17 DNA clone has also been used to detect viral RNA in infected sheep blood. This information has led us to develop a simple and sensitive procedure for the detection of viral genome-biotinylated clone DNA hybrids in vivo or in cultured cells following direct staining with either the avidin-fluorescein complex or the streptavidin-horseradish peroxidase complex.

Animals↗
PubMed1985

Transpositional Mutagenesis of Thiobacillus novellus and Thiobacillus versutus.

Transpositional mutagenesis of Thiobacillus novellus by Tn501 was achieved by means of the incompatibility of IncP plasmids. Tn501 insertion caused three types of mutant phenotypes: isoleucine auxotrophy, lysine auxotrophy, and a reduced ability to oxidize reduced sulfur compounds and to fix CO(2). Oxidation rates for elemental sulfur (S), thiosulfate (S(2)O(3)), and tetrathionate (S(4)O(6)) in mutants of the latter type were reduced relative to those of the nonmutant control strain. Incorporation of labeled bicarbonate (HCO(3)) was also significantly impaired. Although suicide vehicles were not useful for the introduction of transposons into T. novellus, this method was effective for the Tn1721-induced mutagenesis of Thiobacillus versutus. Tn1721 insertions resulted in the loss of the natural resistance of T. versutus to arsenate and gentamicin and in auxotrophies for isoleucine-valine, arginine, phenylalanine, valine, and panthothenate. Transpositional mutagenesis by either method should prove to be a useful tool for further study of these and other members of the genus Thiobacillus.

Journal Article↗
PubMed1985

Complete sequence of bluetongue virus L2 RNA that codes for the antigen recognized by neutralizing antibodies.

The complete sequence of the RNA which encodes the major outer-shell-neutralizing antigen (VP2) of bluetongue virus serotype 10 was determined from overlapping cDNA clones inserted into pBR322. The segment L2 RNA was 2,926 base pairs long (1.87 X 10(6) daltons) and had, in one strand, an open reading frame capable of coding for a protein that had a calculated size of 111,122 daltons (956 amino acids) and a +11.5 net charge. The coding strands of both the L2 gene and the group-specific L3 gene of bluetongue virus serotype 17 (M. Purdy, J. Petre, and P. Roy, J. Virol. 51:754-759, 1984) had common sequences of some six nucleotides at their 5' termini (namely, GUUAAA...) and eight nucleotides (namely, ...ACACUUAC) at their 3' termini. Both had short 5' noncoding regions with AUG codons at residues 20 to 22 (L2) and 18 to 20 (L3). The sequences flanking these AUG codons were similar (A/GCCAUGG). The 3' noncoding regions were longer (36 nucleotides for L2, 49 nucleotides for L3). The predicted amino acid sequence of the L2, compared with the similarly sized L3 gene product, was rich in cysteine residues and charged amino acids.

Antigens, Viral↗
PubMed1985

Cloning and nucleotide sequencing of bluetongue virus genomes.

This is the 1st report of molecular cloning of bluetongue virus (BTV) gene using DNA recombinant techniques. A number of complete and overlapping clones of BTV genes have been cloned into pBR322 by standard procedures with some modification. The full length clones were confirmed by matching the terminal cDNA nucleotide sequences with those previously determined for the termini of double-stranded genomic RNA (Rao et al., 1983). The complete sequence of the cDNA clone of RNA segment 3 of US serotype 17 as determined by the method of Maxam and Gilbert (1980) has been presented here. The clone is 2,772 nucleotides (1.78 X 10(6) daltons) long excluding the 3' polyadenylic acid sequence and has an open reading frame which encodes a protein of some 901 amino acids (103,412 daltons).

Amino Acid Sequence↗
PubMed1985

Molecular epidemiology of two US orbiviruses: bluetongue virus and epizootic hemorrhagic disease virus.

The degree of relatedness between 4 US serotypes (10, 11, 13 and 17) of bluetongue (BT) virus (BTV) were determined by both oligonucleotide fingerprint analyses of double-stranded (ds) RNA as well as tryptic peptide analyses of viral coded polypeptides. Similar studies were undertaken using different alternate isolates of particular serotypes as well as 2 serotypes (1 and 2) of epizootic hemorrhagic disease (EHD) virus (EHDV), a closely related serogroup of orbiviruses. The results indicate that all BT viruses are genetically related to each other and although EHDV-1 and EHDV-2 originated from a common gene pool, the 2 serogroups, EHDV and BTV, are not genetically interactive.

Bluetongue virus↗
PubMed1985

Iohexol: a new, nonionic agent in adult peripheral arteriography.

The safety and efficacy of iohexol, a new nonionic contrast agent, were compared with a diatrizoate (Renografin-76) in a double-blind, parallel study of peripheral arteriography by femoral puncture in 60 patients. Extra-large field serial peripheral arteriography was used and a posterior tibial nerve block was applied to all patients in the study. Similar changes in blood chemistry were observed following the injection of iohexol and diatrizoate but these changes did not require corrective measures. Significantly more patients complained of a sensation of severe heat after receiving diatrizoate (38%) than after the injection of iohexol (10%) (p = 0.001). Four patients in the diatrizoate group experienced one or more adverse reactions, including mild urticaria. Only mild nausea was reported by a single patient in the iohexol group. Overall, 100% of the studies were diagnostic but more of the radiographs taken after the injection of iohexol were rated excellent than after the injection of diatrizoate.

Adult↗
PubMed1984

Comparison of the primary sequence of spring viremia of carp virus M protein with that of vesicular stomatitis virus.

The nucleotide sequence of Spring viremia of carp virus mRNA coding for the matrix protein (M) has been determined from a complete DNA copy cloned in the Escherichia coli plasmid pBR322. The clone is 710 nucleotides long and, excluding the 3' homopolymeric end (representing the mRNA polyadenylic acid sequence), encodes a protein of some 223 amino acids (25,600 Da). The protein has more basic than acidic amino acids and no significant amino- or carboxy-terminal hydrophobic domains. The predicted amino acid sequence of the M protein of Spring viremia of carp virus can be aligned with that of vesicular stomatitis virus, revealing a significant amount of homology (28%). The carboxy-terminal regions of the two proteins exhibit much less homology than their amino termini.

Amino Acid Sequence↗
PubMed1984

Cloning of the bluetongue virus L3 gene.

The genes of the bluetongue virus (BTV) serotype 17 have been cloned into pBR322 by tailing both strands of the double-stranded RNA with polyadenylic acid, transcribing them with reverse transcriptase with an oligodeoxythymidylic acid primer, hybridizing the cDNA products, and completing them into duplex structures with the Klenow fragment of Escherichia coli DNA polymerase. After cloning the double-stranded cDNA molecules into pBR322, the complete sequence of the cloned L3 gene was determined. The clone is 2,772 nucleotides long (1.78 X 10(6) daltons), excluding the 3' polyadenylic acid sequence, and has an open reading frame which codes for a protein of some 901 amino acids (103,412 daltons). This clone can hybridize L3 RNA segments of three other U.S. BTV serotypes, BTV-10, -11, and -13 in addition to -17 but not the equivalent RNA segment of epizootic hemorrhagic disease virus of deer, an orbivirus related to BTV.

Animals↗
PubMed1984

Intra-arterial infusion chemotherapy in rectal cancer.

Chemotherapy by intra-arterial infusion, using mitomycin C and 5-fluorouracil, was administered to six patients with cancer of the rectum. In three patients who presented initially with an inoperable rectal tumour, medication was infused through the inferior mesenteric artery. Tumour regression was documented in all three, allowing subsequent resection in two. Of three other patients with locally recurrent rectal cancer, none showed tumour regression after infusion, but two experienced substantial relief of perineal pain, with improvement in the quality of life. Unexpected complications occurred in the form of a reversible ischemic colitis in two patients and an arterioenteric fistula in a third.

Aged↗