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Biomedical subjects

D J Wright

Publications and source records attributed to D J Wright.

At least 181 records · Page 10Linked to original sources

Emerging pattern of Lyme disease in the United Kingdom and Irish Republic.

In the past year there have been 68 cases of Lyme disease in the United Kingdom and Republic of Ireland. 41 patients had erythema chronicum migrans, and 8 of them had associated neurological disease. 13 further patients presented with neurological disease without a preceding skin lesion. Myocarditis was present in 1 patient. Ixodes ricinus was confirmed as the vector for Lyme disease. In two areas deer were found to be infected by Borrelia burgdorferi, the causative organism of Lyme disease. 86% of 45 deer sera tested had significant antibody titres against B burgdorferi.

Adolescent↗

Resolution of pea legumin subunits by high-performance liquid chromatography.

Pea legumin was dissociated into its component subunits by 6 M urea: these were subsequently fractionated by FPLC using a combination of Mono P, Mono Q, and Mono S columns. The resolution and speed of separation were greatly improved in comparison with previous fractionations. Twelve discrete fractions were obtained and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Six "normal" legumin subunits (Mr 60,000) were identified as well as some "large" (Mr 66,000) and "small" (Mr 44,000) subunits. A few polypeptides of unknown origin were also observed. Four subunits were purified to homogeneity as adjudged by electrophoresis and HPLC and in sufficient yields to permit further studies. Anomalous electrophoretic behavior of the legumin subunits was also observed.

Chromatography, High Pressure Liquid↗

Retention, localization and staining of lipids in tissues embedded in water-miscible methacrylates: using the solubility parameter to analyse the influences of resins, plasticizers, and other reagents.

The influences of a wide variety of technical factors (the nature of the monomer and plasticizer, the duration and temperatures of the processing steps, etc.) on retention, localization and staining of lipid in tissues embedded in water-miscible methacrylates were assessed experimentally. This analysis was aided by the use of the solubility parameters of the substances as quantitative indicators of miscibility. The technical requirements for, and limits of, lipid histochemistry using resin sections have therefore been established on a quantitative basis.

Acrylates↗

The role of bone and liver scans in surveying patients with breast cancer for metastatic disease.

The objective of this study is to correlate the presence of bone and liver metastases in patients with breast cancer with respect to the results of bone and liver scans, axillary nodal status, and serum alkaline phosphatase levels. One hundred ninety-seven patients with breast cancer treated by modified radical mastectomy between the years 1978 and 1981 were studied. Fifty-nine (30%) of the total group had distant metastases during the course of observation of 60 to 96 months; of 35 patients in whom bone metastases developed, 30 had normal preoperative bone scan results. Of 21 patients who had liver metastases, 19 had normal preoperative liver scans. Nineteen (70%) of the 27 patients with abnormal bone scans had normal alkaline phosphatase levels. Seven (63%) of the 11 patients who had abnormal liver scans had a normal alkaline phosphatase. The study supports the concept that preoperative bone and liver scans are ineffective indicators of metastatic involvement. Selection of patients for screening by bone and liver scans according to alkaline phosphatase determinations was not supported by this study. The appropriate use of bone scans for screening in patients with breast carcinoma is suggested as a follow-up device in patients with positive lymph nodes.

Alkaline Phosphatase↗

Assaying erythrocyte haem biosynthetic enzyme activities by high-performance liquid chromatography with the advanced automated sample processor.

The four cytosolic haem biosynthetic enzymes in erythrocytes were assayed with the Varian advanced automated sample processor (AASP) for rapid sample concentration and clean-up with fast and effective high-performance liquid chromatography systems for separation and quantitation. In the assay for 5-aminolaevulinic acid dehydrase, the porphobilinogen (PBG) formed was extracted on a C18 AASP cartridge and separated by reversed-phase ion-pair chromatography with 32% methanol in 0.05 M sodium acetate buffer (pH 3.5), containing 5.4 mM of 1-heptane-sulphonic acid as eluent. PBG was the substrate for the simultaneous assay of hydroxymethylbilane synthase and uroporphyrinogen III synthase. The uroporphyrinogen I and III isomers formed were oxidised to porphyrins, concentrated on a C2 or C8 cartridge, and separated by reversed-phase chromatography with 13% acetonitrile in 1 M ammonium acetate buffer (pH 5.16) as eluent. Uroporphyrinogen decarboxylase was estimated with pentacarboxylic porphyrinogen III as substrate. The coproporphyrinogen formed was extracted on a C2 or C8 cartridge, oxidised to coproporphyrin and separated by reversed-phase chromatography with 30% acetonitrile in 1 M ammonium acetate buffer (pH 5.16) as mobile phase.

Ammonia-Lyases↗

Topography of projections from the medial prefrontal cortex to the amygdala in the rat.

The projections from the rat medial prefrontal cortex to the amygdaloid complex were investigated using retrograde transport of fluorescent dyes and anterograde transport of horseradish peroxidase-WGA. The ventral anterior cingulate, prelimbic, infralimbic and medial orbital areas and the taenia tecta were found to project to the amygdaloid complex. The projections from the prelimbic area arose bilaterally. The medial orbital, prelimbic and anterior cingulate areas send convergent projections to the basolateral nucleus. The prelimbic area has additional projections to the posterolateral cortical nucleus and amygdalo-hippocampal area. The infralimbic area does not project to the basolateral nucleus and cortico-amygdaloid projections from this area are focussed on the anterior cortical nucleus and the anterior amygdaloid area. Both prelimbic and infralimbic areas project to an area situated between the central, medial and basomedial nuclei. Based on similar projections, this area appears to be a caudal continuation of the anterior amygdaloid area. The results indicate that the medial prefrontal component of the "basolateral limbic circuit" is restricted to the anterior cingulate and prelimbic areas. No evidence was obtained to support the existence of a medial prefronto-amygdaloid component of the "visceral forebrain".

Amidines↗

The adjusted serum calcium concept--a reappraisal.

The relationship between serum calcium and albumin was studied using a data base containing biochemical results on approximately 687,000 samples. To exclude patients with established bone, liver and kidney disease, calcium and albumin values had to be accompanied by additional results falling within the laboratory reference range for urea, phosphate, globulin, alkaline phosphatase and aspartate transaminase activities. The regression coefficients of calcium on albumin changed significantly following a change of instrumentation, even though the analytical principles of the methods remained the same. In addition, using standard laboratory methods, the relationship between calcium and albumin deviated from linearity at albumin concentrations less than 30 g/L. Care is needed in the selection and clinical application of factors for the adjustment of serum calcium for changes in the concentration of circulating albumin. Using a large data base, an albumin-related reference range for serum calcium may be calculated, eliminating the need for adjusting calcium values.

Calcium↗

Glucose and insulin homeostasis during the Jarisch-Herxheimer reaction.

Plasma concentrations of glucose and insulin were measured in ten patients during the Jarisch-Herxheimer reaction of tetracycline-treated louse-borne relapsing fever. Plasma glucose fell significantly in eight of the ten patients associated with the peak of the reaction, but plasma insulin remained low. Glucoregulation by insulin was therefore normal. This evidence questions the role of macrophage mediator-induced pancreatic insulin release in causing hypoglycaemia in borreliosis or bacterial endotoxicosis.

Adolescent↗

Influence of tubocurarine, pancuronium and atracurium on bronchomotor tone.

Specific airways conductance (s.Gaw) was measured using the forced airflow oscillation method to study the effects of tubocurarine, pancuronium and atracurium. Twenty-seven patients undergoing elective surgery were randomly allocated to receive one of the three drugs. A statistically significant mean change in s.Gaw from the baseline values for each drug was apparent only after administration of atracurium (at 6 min) (P less than 005). Some individuals given atracurium or tubocurarine either showed large decreases in s.Gaw or cutaneous flushing, but only one patient showed both. Pharmacological release of histamine may be confined to individual tissues in these instances.

Adult↗

Metabolism of the carcinogen 7-methylbenz[c]-acridine in the rat.

The biliary excretion of radioactivity by adult Wistar rats given i.v. 7-methyl-[7-14C]benz[c]acridine(14C-7-MBAC) and [methyl-3H]-7-methylbenz[c]acridine (3H-7-MBAC) (2 mg/kg) was 61% and 48%, respectively, in males in six hours. Females excreted 33% of a 2 mg/kg dose of 3H-7-MBAC in the same time-period. For male rats, the urinary and faecal excretions were about 10% and 61% of the dose of 14C-7-MBAC, respectively, in seven days. No enterohepatic circulation could be demonstrated in control male rats. The biliary excretion of radioactivity by phenobarbital- and 3-methylcholanthrene-induced male rats given 14C-7-MBAC was similar to or greater than that of control male rats. The organo-soluble biliary metabolites after beta-glucuronidase/arylsulphatase hydrolysis were separated by h.p.l.c., and quantitative metabolite distributions were obtained for induced and control rats by comparison with metabolite standards. The mutagenicity of bile from carcinogen-dosed control rats was greater than that of equivalent bile from carcinogen-dosed 3-methylcholanthrene-pretreated animals.

Acridines↗

A computerized approach to the analysis of oligosaccharide structure by high-resolution proton n.m.r.

The 500 MHz proton-n.m.r. spectra of 21 oligosaccharides, predominantly of the lacto-N and lacto-N-neo series and their derivatives containing non-reducing terminal fucose, sialic acid or N-acetylgalactosamine and reduced-end hexitol or hexosaminitol, were examined with 2H2O as solvent. The chemical-shift data obtained from analysis of the spectra were collated with data from other laboratories who have used 250-500 MHz n.m.r. in the analysis of secreted and chemically synthesized oligosaccharides and of the O- and N-linked chains of glycoproteins. A referenced computer library was constructed that includes the chemical shifts of monosaccharides within oligosaccharide sequences that make up the majority of the carbohydrate structures found in mammalian glycoproteins. Examples are given of the computerized interrogation of this library for the assignment of possible structures of unknown oligosaccharides.

Chemical Phenomena↗