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Biomedical subjects

D J Carmichael

Publications and source records attributed to D J Carmichael.

At least 37 records · Page 2Linked to original sources
PubMed1981

'Nephrotoxicity' and metabolic acidosis in transplant patients on cyclosporin A.

Renal function, as represented by serum creatinine and creatinine clearance, 18 to 24 months after renal transplantation was studied in 21 patients receiving Cyclosporin A and compared with that of 25 patients on corticosteroids and azathioprine. Although renal function at six months post transplantation was significantly poorer in those patients on Cyclosporin A compared with those on conventional therapy, it did not deteriorate with time. No significant alteration in renal function was observed in five hepatic transplant recipients on Cyclosporin A after three months. Lower serum bicarbonate was observed more frequently in those renal transplant recipients on Cyclosporin A than in those on conventional therapy, reflecting possible tubular damage.

Acidosis↗
PubMed1979

Biochemical characterization of guanidinium chloride-soluble dentine collagen from lathyritic-rat incisors.

alpha- and beta-Chains were isolated by sequential ion-exchange and gel-filtration chromatography of guanidinium chloride-soluble dentine collagen obtained from Tris/NaCl-extracted EDTA-demineralized lathyritic-rat incisors. The alpha-chains were identified as alpha 1 I and alpha 2 by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and amino acid analysis of the intact chains and their CNBr peptides. The dentine alpha-chains exhibited higher lysine hydroxylation and phosphate content, but lower hydroxylysine glycosylation, than alpha-chains from skin. Increased lysine hydroxylation was observed in the helical sequences. The alpha 1 I/alpha 2 ratio was approx. 3:1, and was presumably due to the presence of (alpha 1 I)3 molecules along with (alpha 1 I)2 alpha 2 molecules as shown recently for neutral-salt-soluble dentine collagen [Wohllebe & Carmichael (1978) Eur. J. Biochem. 92, 183--188]. In the borohydride-reduced beta 11- and beta 12-chains from guanidinium chloride-soluble dentine collagen, the reduced cross-links hydroxylysinohydroxynorleucine and hydroxylysinonorleucine were present. A higher proportion of hydroxylysinonorleucine in the reduced beta 12-chain probably reflects differences in extent of hydroxylation of specific lysine residues of the alpha 1 I- and alpha 2-chains.

Amino Acids↗
PubMed1979

The collagenous matrix of bovine predentine.

Predentine obtained from bovine teeth by microdissection was solubilized by cyanogen bromide cleavage. The electrophoretic mobility of the resultant peptides was established on polyacrylamide gel and the amino acid composition of several peptides was determined. The data clearly indicated that this collagen is entirely of the Type I genetic species. No differences were detected between the predentine and dentine collagens except that the mature tissue was more highly crosslinked. Nevertheless the amount of stable cross-link formed in the predentine was higher than expected for an immature tissue.

Amino Acids↗
PubMed1979

Uhl's anomaly.

Uhl's anomaly of the heart is a rare condition. Another well-documented case is presented with a review of the published reports outlining the main clinical features and the bad overall prognosis. Right atriotomy should be avoided if closure of the atrial septal defect is attempted.

Adult↗
PubMed1979

A biochemical and clinical comparison of two commercially available creatine kinase iso-enzyme MB assay kits suitable for use in the routine medical laboratory.

Two methods for the measurement of plasma creatine kinase MB (CK-MB) activity were compared for analytical performance, cost, practicality, and diagnostic correlation with clinical and electrocardiographic findings in patients admitted to the coronary care unit of a district general hospital. The methods were column chromatography and immunoinhibition. Both methods were found acceptable, and the method to be adopted would depend on the staff arrangements and resources available in the laboratory.

Chromatography↗
PubMed1978

Type-I trimer and type-I collagen in neutral-salt-soluble lathyritic-rat dentine.

Triple-helical collagen molecules have been obtained from EDTA-demineralized lathyritic rat incisors by neutral buffer extraction. Component alpha chains, isolated by sequential ion-exchange and gel-filtration chromatography, were shown to be alpha1 I and alpha2 chains by cyanogen bromide peptide analysis. The alpha1 I:alpha2 chain ratio was approximately 3:1, which is greater than expected for type I collagen. The excess of alpha1 I chains over that required for type I collagen was due to the presence of type I trimer molecules. Fractional salt precipitation separated type I collagen from type I trimer. It is not known at present if type I trimer synthesis also occurs in normal rat tissues.

Animals↗
PubMed1977

Oral disopyramide for the prevention of arrhythmias in patients with acute myocardial infarction admitted to open wards.

Patients with acute myocardial infarction admitted to open wards of three hospitals were given either oral disopyramide (100 mg four times daily) or matching placebo, prophylactically, for seven days. The drug was associated with a significant reduction in mortality (p = 0-0025) and in incidence of extension of infarction (p = 0-01), ventricular fibrillation (p = 0-05), and ventricular tachycardia (p = 0-01). Disopyramide was not associated with any particular complication or side-effect. Unitl information is available to the contrary, oral disopyramide should be given for the first seven days after myocardial infarction to all patients not managed in an intensive-care unit.

Acute Disease↗
PubMed1977

The solubilization of bone and dentin collagens by pepsin. Effect of cross-linkages and non-collagen components.

Bone and dentin collagen are less susceptible to solubilization by pepsin digestion then is skin collagen. Digestion at 4 degrees C for 72 h solubilized only 35.3% of bovine cortical bone and 5.6% of bovine dentin compared with nearly 100% dissolution of bovine skin. Sodium dodecyl sulfate-acrylamide gel electrophoresis and molecular sieve chromatography showed that, for bone and dentin, intact alpha chains and cross-linked aggregates of beta, gamma and higher weight remained intact after pepsin solubilization but lower molecular weight fragments also were prevalent indicating chain scission in helical regions. Electron microscopic examination of segment long spacing precipitates of the soluble collagens confirmed the presence of solubilized polymerized collagen. The principal reducible cross-link in both bone and dentin was the precursor of dihydroxylsinonorleucine and this cross-link was also present in the solubilized collagens. Small amounts of non-collagenous proteins and glycosaminoglycans of different compositions in dentin and bone resisted extraction before pepsin digestion. However, the differences in solubilization of the collagens have been related to differences in cross-linkage placement.

Amino Acids↗
PubMed1977

Carrageenin-induced arthritis. IV. Rate changes in cartilage matrix proteoglycan synthesis.

A localized inflammatory response was initiated by both single and repeated injections of carrageenin into femorotibial joints. Histologic changes were observed 24 hours after a single intraarticular injection, and an inhibition in the in vitro rate of proteoglycan synthesis was detected 72 hours after the injection. This inhibition was relieved in vitro by the addition of beta-D-xyloside, an exogenous initiator of glycosaminoglycan biosynthesis. Following repeated carrageenin injections, most cells appeared to be dead on histologic examination and no in vitro proteoglycan synthesis could be detected; nor could any stimulation be achieved by adding exyloside.

Animals↗
PubMed1975

The composition of the insoluble collagenous matrix of bovine predentine.

Predentine obtained from bovine teeth by microdissection was extracted with EDTA and tris-NaCl solutions. The insoluble residue consisted mainly of collagen and resembled dentine collagen in overall amino acid composition. The residue differed in containing no detectable phosphoprotein, a much larger amount of collagen hexose and more non-collagenous glycoprotein, the neutral sugar composition of which was determined. Differences were also observed in the contents of reducible collagen cross-links. Half of the total phosphorus found in the predentine could not be accounted for solely by hydroxyapatite. The remainder was partly soluble and dialysable.

Amino Acids↗
PubMed1975

Bovine periodontal ligament. An invesitation of the collagen, glycosaminoglycan and insoluble glycoprotein components at different stages of tissue development.

Periodontal ligaments from unerupted, partially erupted and mature teeth were extracted with 0.15 M NaCl. The major reducible collagen cross-link in each insoluble fraction was dehydrodihydroxylysinonorleucine; the dehydroydroxylysinonorleucine contents were smaller. There was no significant difference in the quantities of these cross-links relative to collagen contents in the three speciments, but one of the precursors, hydroxyallysine, markedly decreased in the older tissue. The amino acid compositions of the trypsin-resistant insoluble fractions were generally characteristic of collagen. Analyses of separated glycopeptides revealed the presence of insoluble non-collagenous glycoproteins and collagen hexoses. The latter were lower in the mature ligament. Hyaluronic acid progressively decreased relative to chondroitin sulphate on eruption and maturation. A hyaluronidase-resistant glycosaminoglycan, probably dermatan sulphate, occurred in the NaCl-insoluble fraction of the mature ligament and in appreciable amounts in all NaCl extracts.

Animals↗