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Biomedical subjects

R Jordan

Publications and source records attributed to R Jordan.

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

Demonstration of c-erbB-2 oncogene overexpression in salivary gland neoplasms by in situ hybridization.

The level of c-erbB-2 cellular mRNA in 18 salivary gland tumours and in 7 normal salivary glands was determined by in situ hybridization using [35S] labelled RNA probes. Computer assisted quantitation of the autoradiographic signal indicated a significantly higher c-erbB-2 expression in the tumour group (22.64 grains per cell +/- 3.79; 95% CI) as compared to the non-neoplastic salivary gland tissue (4.11 +/- 0.90; 95% CI). The c-erbB-2 expression as measured by grain counts per cell for the pleomorphic adenomas (16.29 +/- 1.87; 95% CI), mucoepidermoid carcinomas (31.52 +/- 0.08; 95% CI) and the acinic cell carcinomas (44.24 +/- 17.11; 95% CI) were significantly greater than the expression for the normal group. The acinic cell carcinomas exhibited the greatest level of expression. As observed at the individual cell level, the autoradiographic signal was distributed uniformly in the neoplastic tissues, regardless of the cell type. This study confirms the hypothesis that the c-erbB-2 oncogene is overexpressed at the mRNA level in salivary gland tumours.

Adenoma, Pleomorphic↗
PubMed1994

Propofol, seizures and generalized paroxysmal fast activity in the EEG.

Propofol is a relatively new anesthetic agent used in outpatient surgery. Some investigators use it in the treatment of status epilepticus and in epilepsy surgery and have concluded that propofol has an anticonvulsant effect. Cases of seizure-like behaviors, myoclonus and opisthotonus following propofol anesthesia have been reported. Although rare, official warnings about this association have been issued. Different EEG abnormalities, and no abnormality, have been associated with propofol. We report a case of a healthy man who developed nonconvulsive seizures and generalized paroxysmal fast activity in his EEG following use of propofol for anesthesia.

Adult↗
PubMed1994

Noninvolvement of the X chromosome in radiation-induced chromosome translocations in the human lymphoblastoid cell line TK6.

Fluorescence in situ hybridization procedures were used to examine the influence of chromosome locus on the frequency and type of chromosome aberrations induced by 60Co gamma rays in the human lymphoblastoid cell line TK6. Aberrations involving the X chromosome were compared to those involving the similarly sized autosome chromosome 7. When corrected for DNA content, acentric fragments were induced with equal frequency in the X and 7 chromosomes. Dose-dependent increases in chromosomal interchanges involving chromosome 7 were noted and the frequencies of balanced translocations and dicentrics produced were approximately equal. Chromosome interchanges involving the X chromosome were rare and showed no apparent dose dependence. Thus, while chromosomes 7 and X are equally sensitive to the induction of chromosome breaks, the X chromosome is much less likely to interact with autosomes than chromosome 7. The noninvolvement of the X chromosome in translocations with autosomes may reflect a more peripheral and separate location for the X chromosome in the mammalian nucleus.

Cell Line↗
PubMed1993

Thermodynamic and structural analysis of the folding/unfolding transitions of the Escherichia coli molecular chaperone DnaK.

The thermal unfolding of the Escherichia coli 70 kDa heat shock protein, DnaK, exhibits three well defined transitions. At pH 7.6, these transitions are centered at 45.2, 58.0 and 73.3 degrees C. High sensitivity calorimetric scans as a function of pH indicate that the folding/unfolding behavior is well described by a four-state model which includes a delta H, tm and delta Cp for each state. Calorimetric scans of a 44 kDa N-terminal proteolytic fragment show a major transition centered at 47.5 degrees C (N1) and a minor transition at 79.4 degrees C (N2). A calorimetric scan of a 23 kDa C-terminal proteolytic fragment exhibits a low temperature peak at 58.5 degrees C (C1) and a high temperature peak at 70.6 degrees C (C2). Deconvolution analysis of the low temperature peak reveals that it is actually composed of two transitions of roughly equal delta H centered at 50.4 degrees C (C1a) and 58.2 degrees C(C1b). These experiments have allowed us to assign the transitions of the intact protein as follows. The low temperature transition of DnaK can be assigned to the N-terminal region on the basis of the similarity between the delta H and tm values for the low temperature transition and those obtained for the N1 transition of the isolated N-terminal fragment. This assignment is also supported by measurements of the intrinsic fluorescence emission as a function of temperature. DnaK contains a single tryptophan localized at residue 102 in the N-terminal domain of the protein. Additionally, calorimetric scans show that the tm of the low temperature transition increases by 9.2 degrees C in the presence of excess ADP, which is known to bind to the N-terminal domain. The middle transition can be assigned to the C1a and C1b transitions of the C-terminal fragment on the basis of the similarity of delta H and tm. In the intact protein C1a and C1b form a single cooperative unit; however, the cooperative interactions between these folding/unfolding domains are disrupted in the isolated fragment. The high temperature transition of the intact protein is composed of contributions from both the N-terminal and C-terminal regions of the protein. These studies have allowed us to develop a quantitative model of the folding/unfolding behavior of DnaK.

Bacterial Proteins↗
PubMed1993

Control of intrinsic buccal muscles by motoneurons B11, B15, and B16 in Aplysia californica.

To further define the control of intrinsic buccal muscles by identified motoneurons B11, B15, and B16 in Aplysia californica, we made physiological recordings from semi-intact and isolated preparations of the buccal ganglia and buccal mass. B15 and B16 were previously known to innervate muscle 15 (also called the accessory radula closer muscle). We show here that these motoneurons also innervate other buccal muscles ipsilateral to their cell bodies; for example, B15 reliably innervates and can cause contraction in intrinsic muscle I4. Likewise, B11 appears to innervate all of the intrinsic buccal muscles, but elicits contractions only in I4. The form and time course of synaptic plasticity displayed by these motoneurons is common to all the muscles they innervate. No evidence for electrical coupling between fibers of adjacent muscles could be obtained, suggesting that all recorded innervation is direct. Like B15 and B16 (Cohen et al., '78), B11 neuromuscular synapses appear to be cholinergic, since they are reversibly antagonized by hexamethonium and d-tubocurarine (acetylcholine [ACh] receptor antagonists). In addition, direct application of ACh elicits depolarizing responses and contractions in I4 which are also blocked by hexamethonium. Application of glutamate and GABA do not elicit depolarizations or contractions in I4 or I5. We conclude that these motoneurons control radula position through complex synaptic actions on multiple intrinsic buccal muscles, using ACh as their conventional transmitter.

Acetylcholine↗
PubMed1993

The lower-lid retractors in congenital entropion and epiblepharon.

A case of congenital entropion is presented in which the lower-lid crease was lost during entropion surgery, yielding a postoperative condition resembling an epiblepharon. The case suggests that deficiencies in the lower-lid retractor fibers are a key factor in the pathogenesis of both congenital entropion and epiblepharon.

Child↗
PubMed1992

Development of a monoclonal antibody to the conserved region of p34cdc2 protein kinase.

Mice and rabbits were injected with various forms of a 16 amino acid synthetic peptide representing PSTAIR, the evolutionarily conserved region of the protein kinase p34cdc2, for polyclonal antisera and hybridoma-monoclonal antibody production. Antisera from mice injected with an unconjugated monomeric form of the peptide showed no reaction to the peptide. Of four animals injected with the monomeric form of the peptide conjugated to keyhole limpet hemocyanin via m-maleimidobenzoyl-N-hydroxysulfosuccinimide (MBS), antisera from only one mouse had a very low titer to the peptide, and all four animals produced antibody to the MBS bridge. Both mice injected with an octameric multiple antigen peptide (MAP) of PSTAIR produced antisera reactive to the octameric MAP form of the peptide in ELISA and also to the cdc2 protein expressed in bacteria in an immunoblotting assay. Splenocytes from one mouse injected with the octameric MAP form of the peptide were successfully used for hybridoma-monoclonal antibody production. A monoclonal antibody was produced that reacted with octamer, monomer and cdc2-expressed protein and specifically with the carboxyl terminus of the 16 amino acid peptide.

Amino Acid Sequence↗
PubMed1992

Synthesis and biological activity of trans(+-)-N-methyl-2-(3-pyridyl)-2-tetrahydrothiopyrancarbothioamide 1-oxide (RP 49356) and analogues: a new class of potassium channel opener.

The synthesis and biological activity of trans-(+-)-N-methyl-2-(3-pyridyl)-2-tetrahydrothiopyrancarbothioamid+ ++ e 1-oxide (8a, RP 49356) and analogues is reported. These compounds constitute a new structural class of K(+)-channel opener. The effects of changes in pyridyl group, thioamide, and thiane ring on in vitro K(+)-channel opening reactivity are discussed. A 3-pyridyl or 3-quinolyl group, a small N-alkyl thioamide function, and a thiane oxide ring, in which the sulfoxide is in a trans relationship to the thioamide, are preferred for activity. Selected compounds were tested intravenously in the normotensive anaesthetized rat for hypotensive effects, and the activities reflect their in vitro K(+)-channel opening activity. This led to further evaluation of compound 8a and the selection of the (-)-enantiomer 8b (RP 52891) for development as an antihypertensive and antianginal agent.

Animals↗
PubMed1992

Different conformations for the same polypeptide bound to chaperones DnaK and GroEL.

The proteins DnaK (hsp70) and GroEL (cpn60) from Escherichia coli are prototypes of two classes of molecular chaperones conserved throughout evolution. The analysis of transferred nuclear Overhauser effects in two-dimensional NMR spectra is ideally suited to determine chaperone-bound conformations of peptides. The peptide vsv-C (amino-acid sequence KLIGVLSSLFRPK) stimulates the ATPase of BiP and Hsc70 (ref. 3) and the intrinsic ATPase of DnaK. The affinity of the vsv-C peptide for DnaK is greatly reduced in the presence of ATP. Here we analyse transferred nuclear Overhauser effects and show that the peptide is in an extended conformation while bound to DnaK but is helical when bound to GroEL. NMR also indicates that the mobility of the peptide backbone is reduced more by binding to DnaK than by binding to GroEL, whereas the side chains are less mobile when bound to GroEL.

Amino Acid Sequence↗
PubMed1992

Vein grafts in reconstructive microsurgery of the lower extremity.

This paper describes surgical techniques and results of lower extremity microsurgical reconstruction using vein grafts. During a 5 year period, free tissue transfers were used to reconstruct 118 lower extremity defects in 109 patients. In 28 of these cases (24%), saphenous vein grafts were used when reconstruction would otherwise have been difficult or impossible. A preliminary arteriovenous fistula was established between the proximal arterial source and the final venous drainage in the majority (26) of cases. Venous drainage was left intact at the point of entry into the deep venous system in 23 cases. Three complications included anastomotic clotting in 2 patients and postoperative blow-out of the vein graft in another; all were treated without flap loss. Flap survival was 86% in vein grafted patients and 94% in those cases in which vein grafts were not used. Flap loss was related in each case to the nature of the pre-existing condition, rather than to vein grafting per se.

Arteriovenous Shunt, Surgical↗
PubMed1992

Potyviruses, monoclonal antibodies, and antigenic sites.

Virus-specific and cross-reactive monoclonal antibodies have been produced to at least 19 different aphid-transmitted potyviruses. This report summarizes the development of these monoclonal antibodies as well as presents information on the delineation of the virus-specific and group-common epitopes defined by these monoclonal antibodies. Virus-specific and group-common antigenic determinants were mapped by a variety of techniques, including analysis of antigen: antibody reactivity patterns, determination of N-terminal vs. trypsin-resistant core peptide-specificity, immunoanalysis of overlapping synthetic peptides, and immunoanalysis of bacterially expressed coat-protein gene products. Of those monoclonal antibodies that have been examined, monoclonal antibody-defined virus-specific epitopes are virion surface-located within the 30+ amino acid amino terminus, whereas the group-common epitopes are found in the trypsin-resistant core protein not usually located on the virion surface, as has been shown previously with certain polyclonal antibodies. New information is presented on the analysis of bean yellow mosaic virus amino terminal epitopes as well as on the identification of amino terminal antigenic determinants shared between strains of bean yellow mosaic virus and pepper mottle virus. A recommendation on the evaluation and use of a panel of potyvirus broad-spectrum reacting monoclonals as reference monoclonal antibodies for the detection and classification of aphid-transmitted potyviruses is also presented.

Amino Acid Sequence↗
PubMed1992

Evidence that pepper mottle virus and potato virus Y are distinct viruses: analyses of the coat protein and 3' untranslated sequence of a California isolate of pepper mottle virus.

Pepper mottle virus (PepMoV) is a member of the large and complex genus Potyvirus, and is classically distinguished from other members of the genus by differential host range and cytopathology as well as serology of the coat protein and cytoplasmic inclusion body proteins. Here we report the deduced amino acid sequence of the coat protein of a California potyvirus identified by a variety of classical methods as PepMoV (PepMoV C). Comparison of the 3' untranslated nucleic acid sequence and the deduced coat-protein amino acid sequence of the PepMoV C isolate with those of PVY and other potyviruses indicates that PepMoV C is sufficiently diverged to be considered a distinct virus species. Thus, comparative sequence analyses of the PepMoV C isolate support earlier serological and biological evidence that PepMoV and PVY are distinct viruses.

Amino Acid Sequence↗
PubMed1991

Inhibition of transient gene expression with plasmids encoding herpes simplex virus type 1 UL55 and alpha genes.

Herpes simplex virus type 1 (HSV-1) subgenomic sequences from 0.743 to 0.782 map units have been molecularly cloned as plasmid AT1 and shown to inhibit stable DNA-mediated gene transformation of Ltk- cells with the HSV-1 thymidine kinase (tk) gene. Here it is shown that AT1 also inhibits transient gene expression. Expression from the chloramphenicol acetyltransferase (CAT) gene under the control of either the HSV-1 tk gene or the Rous sarcoma virus (RSV) promoter was inhibited when cotransfected into Ltk- and CV-1 cells with equimolar amounts of AT1. AT1 was subcloned as three overlapping plasmids called AT1a, alpha 27 and AT1b. The alpha 27 plasmid encodes the HSV-1 immediate early gene, alpha 27; AT1a possesses sequences that specify an open reading frame in HSV-1 strain KOS used in these studies, although the significance of this open reading frame is unknown; AT1b possesses the sequences for UL55 and UL56, also genes for which no function has been reported. No single subclone or pair of subclones demonstrated significant inhibition of transient gene expression. Cotransfection of all three subclones did result in inhibition of RSV-CAT gene expression, suggesting that information from each subclone is necessary. One of the three subclones, alpha 27, contains the HSV-1 immediate early gene, alpha 27, so the possibility that other immediate early genes could substitute for alpha 27 was tested. Inhibition of RSV-CAT gene expression was also achieved by cotransfection of AT1a and AT1b with either an alpha 0- or alpha 4-containing plasmid, suggesting that the role of the alpha 27-containing plasmid can be replaced by other alpha genes with trans-regulating capability. Finally, AT1a and AT1b linker insertion mutants have been constructed and used to study the role these plasmids play in mediating inhibition. These results suggest that AT1 contains HSV-1 functions in addition to that of alpha 27 that interfere with gene expression.

Animals↗
PubMed1991

Comparison and differentiation of potyvirus isolates and identification of strain-, virus-, subgroup-specific and potyvirus group-common epitopes using monoclonal antibodies.

A panel of monoclonal antibodies (MAbs) generated against an admixture of 12 potyvirus isolates was used to compare and differentiate diverse potyviruses. Both native and denatured virions of strains of bean yellow mosaic (BYMV), potato virus Y, tobacco etch, pea seed-borne mosaic, iris severe mosaic, iris mild mosaic and asparagus virus-1 potyviruses were used as immunogen and as antigen for screening of the hybridoma cell lines. Thirty cell lines secreting potyvirus-specific antibodies reactive in indirect antigen-coated plate (ACP-) ELISA were selected for detailed analysis. All 30 MAbs reacted with at least one strain of BYMV; 11 MAbs reacted with between one and eight of the nine BYMV strains and an additional three MAbs reacted only with isolates within the BYMV subgroup (BYMV, pea mosaic virus and clover yellow vein virus). The remaining 16 MAbs reacted with a BYMV isolate and with at least one of the other 43 potyvirus isolates tested. MAb PTY 1 reacted with all 55 potyvirus isolates tested (representing at least 33 different and distinct aphid-transmissible potyviruses). The potyvirus cross-reactive MAbs generally gave higher reactivity values in ACP-ELISA with dissociated virus than with polyclonal antibody-trapped intact virions in triple antibody sandwich ELISA (i.e. were cryptotope-specific). The BYMV strain- and virus-specific MAbs reacted strongly with both types of antigens (i.e. were metatope-specific). At least 25 distinct epitopes (12 cryptotopes and 13 metatopes) could be identified from the MAb-antigen reactivity patterns. The distribution of these epitopes between virus isolates can be used to detect and differentiate potyviruses in infected plant extracts and to examine virus architectures. Some of these epitopes are shared by potyvirus isolates not previously shown to be serologically related. The broad spectrum-reacting MAb PTY 1 recognizes a cryptotope conserved on all of the aphid-transmissible potyviruses examined and should be a valuable tool for the detection and assay of these potyviruses.

Antibodies, Monoclonal↗