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Biomedical subjects

R Sinclair

Publications and source records attributed to R Sinclair.

At least 55 records · Page 3Linked to original sources
PubMed1996

The radial artery as a bypass graft.

The radial artery is being reintroduced into clinical practice to increase the number of arterial grafts for patients undergoing coronary artery bypass surgery. The radial artery is readily available from one or both forearms and removal is safe in patients who have a normal collateral circulation to the hand. Harvesting the radial artery with the adjacent veins using a minimal touch technique and vasodilators will prevent vasospasm and possibly early occlusion. A concern is that subclinical atheroma is present in many patients. The radial artery can be used as a single graft, anastomosed in a "Y" fashion with the internal mammary artery, or used as a sequential graft. The early mortality and complications are low. There are potential cost savings because the need for an incision in the leg is avoided, so that patients may be discharged early. The early results of radial artery grafting are encouraging. Further follow-up is required to determine the late patency and effects on survival of using the radial artery graft.

Aged↗
PubMed1996

Postoperative pain relief by topical lidocaine in the surgical wound of hysterectomized patients.

BACKGROUND: To improve postoperative analgesia, local anesthetics have been administered perioperatively as infiltration or as aerosol in the surgical area. A previous study showed good analgesic effects by topical lidocaine in the wound in minor extraabdominal surgery (herniorraphy), while the same treatment in minor lower laparothomies did not improve postoperative analgesia. The present study investigated the effect of topical wound anesthesia using lidocaine aerosol on postoperative pain following major lower abdominal surgery. METHODS: Postoperative pain and analgesic requirements were studied in a double-blind randomized trial including 30 hysterectomized patients. Patients were randomized to receive single wound treatment either with lidocaine aerosol 500 mg (100 mg/ml; Xylocain aerosol, ASTRA, Sweden) (n = 15) or placebo aerosol (n = 15). Postoperative pain was evaluated by visual analogue scale (VAS). Requirements of opiate analgesics (buprenorphine) after surgery were monitored. RESULTS: Lidocaine aerosol induced a significantly (P < 0.001) better analgesia at rest (VAS) and a significant (P < 0.001) reduction in postoperative requirements of buprenorphine during the first 24 hours after surgery compared to placebo aerosol. Differences between the groups in pain scores (VAS) and buprenorphine requirements during the second postoperative day were not significant. Mean pain scores upon mobilization 24 h after surgery were significantly lower in the group receiving lidocaine aerosol (P < 0.05). The plasma lidocaine concentration 4 h after the administration of lidocaine was well below toxic level and plasma lidocaine was detectable 48 h postoperatively. No drug-related side effects were reported. CONCLUSION: A single dose of lidocaine aerosol topically administered in the surgical wound of hysterectomy patients improved analgesia during the first postoperative day with minimal risk of side effects.

Adult↗
PubMed1995

Formation of a porphyrin pi-cation radical in the fluoride complex of horseradish peroxidase.

Horseradish peroxidase (HRP) was oxidized by IrCl6(2-) to a mixture of compounds I and II, the rate of oxidation and the ratio of the mixture being greatly affected by pH (Hayashi & Yamazaki, 1979). Oxidation of HRP by IrCl6(2-) in the presence of fluoride was significantly accelerated. This resulted in the formation of a new compound which is a ferric fluoride complex containing a porphyrin pi-cation radical. The spectrum of the new compound showed a decreased absorption band in the Soret region and a broad band at 570 nm; which was converted to that of the original ferric fluoride complex by addition of ascorbate or hydroquinone. Addition of cyanide slowed down the oxidation of HRP by IrCl6(2-), and the oxidation product was the same as that obtained in the absence of cyanide. Compound I was formed when H2O2 was added to HRP in the presence of fluoride or cyanide. The one-electron reduction potential (Eo') of the oxidized HRP-fluoride complex was measured at several pH values, the Eo' value at pH 7 being 861 +/- 4 mV. The ratio of delta Eo' to delta pH was 49 mV/pH unit.

Ascorbic Acid↗
PubMed1995

X-ray absorption spectroscopy comparison of the active site structures of Phanerochaete chrysosporium lignin peroxidase isoenzymes H2, H3, H4, H5, H8, and H10.

The iron heme and its immediate environment can provide information that is pivotal to our understanding of the structural and mechanistic features that confer unusual properties to the heme peroxidases. X-ray absorption spectroscopy (XAS), which is ideally suited for the investigation of the local environment and electronic structure of the heme iron of hemeproteins, has been used to characterize a variety of lignin peroxidase and manganese-dependent peroxidase isoenzymes produced by the white rot fungus Phanerochaete chrysosporium. The data suggest no differences within the error in the first coordination shell of iron for the isoenzymes H2, H3, H4, H5, H8, and H10 examined in this study. The pyrrole nitrogens are at a distance of 2.05 +/- 0.015 A, and the proximal histidine nitrogens are at 1.93 +/- 0.02 A, while the sixth ligands are located at 2.17 +/- 0.03 A. Significant differences are observed in higher coordination shells which may be related to conformational differences in the heme.

Binding Sites↗
PubMed1995

Development and evaluation of an ELISA using recombinant fusion protein to detect the presence of host antibody to equine arteritis virus.

A recombinant glutathione-S-transferase fusion protein expressing amino acids 55-98 of equine arteritis virus (EAV) GL (rGL 55-98) was tested in an ELISA for its ability to detect serum antibodies to EAV. Host antibodies induced following EAV infection bound the recombinant antigen by ELISA. The ELISA specificity and sensitivity were determined with a panel of equine sera including postinfection and postvaccination samples. A good correlation existed between EAV neutralizing antibody titers and ELISA absorbance values (r = 0.827). The sensitivity and specificity of the ELISA were 99.6 and 90.1%, respectively, compared with EAV neutralization test and the recombinant antigen did not crossreact in ELISA with equine sera directed against other common equine respiratory viruses. Three post-EAV infection equine sera raised against different EAV isolates reacted strongly in the ELISA, as did two equine sera raised against EAV vaccines, indicating that the viral epitope was conserved between the viruses tested. Following vaccination with an inactivated whole virus vaccine, antibody detected with the recombinant antigen ELISA preceded the development of a virus-neutralizing response. The study demonstrates the potential application of rGL 55-98 as a diagnostic antigen.

Animals↗
PubMed1993

An extended X-ray absorption fine structure investigation of the structure of the active site of lactoperoxidase.

Native lactoperoxidase, compound III, and the reduced forms (at pH 6 and 9) were studied using X-ray absorption spectroscopy (XAS). Native lactoperoxidase has four pyrrole nitrogen ligands at an average distance of 2.04 +/- 0.01 A, a proximal ligand at 1.91 +/- 0.02 A, and a sixth (distal) ligand at 2.16 +/- 0.03 A. Lactoperoxidase native enzyme has a first coordination shell structure that is similar to that of native lignin peroxidase [Sinclair, R., Yamazaki, I., Bumpus, J., Brock, B., Chang, C.-S., Albo, A., & Powers, L. (1992) Biochemistry 31, 4892-4900] and different from that of horseradish peroxidase [Chance, B., Powers, L., Ching, Y., Poulos, T., Schonbaum, G., Yamazaki, I., & Paul, K. (1984) Arch. Biochem. Biophys. 235, 596-611]. Similarly, lactoperoxidase compound III resembles lignin peroxidase compound III. The five-coordinated ferrous form was stable at pH 9, but at pH 6 it was rapidly converted to the six-coordinated form with a distal ligand at 2.18 +/- 0.03 A. No evidence typical of changes in spin state was obtained at the different pH values.

Absorptiometry, Photon↗
PubMed1993

pH dependence of the active site of horseradish peroxidase compound II.

Using X-ray absorption spectroscopy, we investigated the active site of horseradish peroxidase (HRP) compound II at two different pH values. The results indicate that the bond length of the sixth coordinated ligand of the active site was 1.90 +/- 0.02 A at pH 7, decreasing to 1.72 +/- 0.02 A at pH 10. The average iron-to-pyrrole nitrogen and the proximal ligand bond lengths showed no significant changes. The position of higher coordination shells around the iron center changed, implying that some movement or deformation of nearby amino acid residues and/or of the heme occurred. Results of this study suggest that the decrease of the Fe-O bond length of HRP compound II at the higher pH might be attributed to the loss of a hydrogen bond which is present between the oxygen ligand and an amino acid residue in the heme pocket at pH 7.

Absorptiometry, Photon↗
PubMed1993

Characterization of an antigenic site on glycoprotein 13 (gC) of equid herpesvirus type-1.

Six monoclonal antibodies directed against EHV-1 glycoprotein 13 were characterized. Five antibodies neutralized EHV-1 and were directed against a single antigenic site which comprised type-specific and type cross-reactive epitopes. Inhibition of monoclonal antibody binding to this site by post-infection equine sera suggests that it is a target of host antibody during natural infection with either EHV-1 or EHV-4.

Animals↗
PubMed1993

Human papillomavirus type 6-induced condylomata: an unusual complication of intertrigo.

A 79-year-old virgo intacta presented with a 20-year-history of intertrigo, and a 3-month history of superimposed warty masses beneath both breasts and in the groin and perianal areas. There was no evidence of immunosuppression. Histology of the warty lesions showed squamous papillomata, with evidence of wart virus infection. Human papillomavirus (HPV) type 6 was identified by in situ DNA hybridization, in the submammary lesions. This is an unusual manifestation of both intertrigo and wart virus infection. HPV-6 is classically found in anogenital warts. We assume that these warts were acquired by a non-venereal route and/or by congenital infection some 78 years ago. We suggest that it is the warm, moist environment, rather than the specific site, which encourages HPV-6 to flourish.

Aged↗
PubMed1993

Inhibitory effects of amide local anaesthetics on stimulus-induced human leukocyte metabolic activation, LTB4 release and IL-1 secretion in vitro.

The anti-inflammatory effects of the amide local anaesthetics lidocaine and bupivacaine were evaluated in vitro by examination of the metabolic activation and secretory responses of human polymorphonuclear granulocytes (PMNGs) and mononuclear cells. Pretreatment with lidocaine or bupivacaine had a dose-dependent inhibitory effect on PMNG luminol-amplified chemiluminescence stimulated by bovine serum albumin (BSA)/anti-BSA immune complexes (IC) or by serum-opsonized zymosan (SOZ) particles. Both lidocaine and bupivacaine inhibited the release of the inflammatory mediators leukotriene B4 (LTB4) and interleukin-1 (IL-1) evaluated by radioimmunoassay (RIA). Pretreatment of suspended PMNGs and monocytes with the anaesthetics caused a marked inhibition of LTB4 release when the cells were stimulated with SOZ. In short-term (24 h) cultures of mononuclear cells the addition of lidocaine or bupivacaine reduced, in a dose-dependent manner, the level of IL-1 detected after stimulation with lipopolysaccharide (LPS). In all three assays (chemiluminescence, LTB4 and IL-1 RIA) bupivacaine was found to be more potent than lidocaine. The present results show that amide local anaesthetics have marked suppressive effects on the metabolic activation and secretory functions of leukocytes stimulated by different agonists. Although the detailed mechanisms for these effects are not known, they may explain part of the potent anti-inflammatory actions of local anaesthetics previously described in vivo.

Antigen-Antibody Complex↗
PubMed1993

Detection of antibodies against equine herpesvirus types 1 and 4 by using recombinant protein derived from an immunodominant region of glycoprotein B.

The N-terminal fragment comprising residues +1 to +50 (gB1-50) of equine herpesvirus type 1 (EHV-1) glycoprotein B was expressed as a glutathione S-transferase fusion protein in Escherichia coli. Recombinant gB1-50 (rgB1-50) was recognized in immunoblots by sera from rabbits immunized with EHV-1 and by convalescent-phase sera from horses with natural EHV-1 infections. An enzyme-linked immunosorbent assay (ELISA) for monitoring antibody levels against EHV-1 was developed by using rgB1-50, and its specificity was assessed with a panel of reference antisera against other equine viruses. A specific cross-reaction was detected with EHV-4, which was confirmed by inhibition ELISA. Convalescent-phase sera from horses with natural EHV-1 or EHV-4 infections possessed antibody titers against rgB1-50 ranging from 1:2,000 to 1:64,000, indicating the presence of an immunodominant antigenic site. The study demonstrated the potential application of rgB1-50 as a diagnostic antigen and highlights the glutathione S-transferase fusion system as a simple and effective method of producing purified milligram quantities of antigen.

Amino Acid Sequence↗
PubMed1993

Production of monoclonal antibodies against equine influenza A/Equi-2 (H3N8) Indian isolate.

Seven hybrid cell lines of mouse myeloma cell line NSO and spleen cells of BALB/c mice producing monoclonal antibodies (MAbs) against equine influenza A/Equi-2/Ludhiana/87 (H3N8) virus were developed. These MAbs were purified, isotyped and characterised by enzyme linked immunosorbent assay (ELISA), fluorescent antibody test (FAT), haemagglutination inhibition (HI) and virus neutralization (VN) tests. The titres of ascitic fluids induced by hybridomas as estimated by ELISA ranged from 1:25,600 to 1:51,200. Monoclonality of these clones was confirmed using a panel of 5 viral antigens, each belonging to a single isotype. MAbs (5) belonged to IgM and one each to IgG1 and IgG2a. Two epitopes appeared to be closely resembling by HI and VN tests but other two epitopes appeared to be different.

Animals↗
PubMed1992

Haloperoxidase activity of Phanerochaete chrysosporium lignin peroxidases H2 and H8.

Monochlorodimedone (MCD), commonly used as a halogen acceptor for haloperoxidase assays, was oxidized by hydrogen peroxide in the presence of lignin peroxidase isoenzymes H2 and H8. When oxidized, it produced a weak absorption band with an intensity that varied with pH. This absorbance was used as a simple method for the product analysis because it disappeared when MCD was brominated or chlorinated. We assessed the activity of the lignin peroxidases for oxidation of bromide by measuring the bromination of MCD, the formation of tribromide, the bromide-mediated oxidation of glutathione, and the bromide-mediated catalase-like activity. We analyzed the reaction products of MCD and the halide-mediated oxidation of glutathione when bromide was replaced by chloride. These enzymes demonstrated no significant activity for oxidation of chloride. Unlike other peroxidases, the lignin peroxidases exhibited similar pH-activity curves for the iodide and bromide oxidations. The optimum pH for activity was about 2.5. Surprisingly, this pH dependence of lignin peroxidase activity for the halides was nearly the same in the reactions with hydrogen donors, such as hydroquinone and guaiacol. The results suggested that protonation of the enzymes with pKa approximately 3.2 is necessary for the catalytic function of lignin peroxidases, irrespective of whether the substrates are electron or hydrogen donors. These unique reaction profiles of lignin peroxidases are compared to those of other peroxidases, such as lactoperoxidase, bromoperoxidase, chloroperoxidase, and horseradish peroxidase. Isozyme H2 was more active than isozyme H8, but isozyme H8 was more stable at very acidic pH.

Basidiomycota↗