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Biomedical subjects

D J Wright

Publications and source records attributed to D J Wright.

At least 19 recordsLinked to original sources
PubMed1992

Staining sections of water-miscible resins. 2. Effects of staining-reagent lipophilicity on the staining of glycol-methacrylate-embedded tissues.

Glycol methacrylate (GMA) sections of animal tissues were stained with a group of twenty-seven reagents of very varied chemical characteristics. The artefactual background staining of the resin was found to be dependent on the hydrophilic/lipophilic character of the staining reagent, as estimated from the logarithm of its octanol-water partition coefficient (log P). Intense background staining occurred with lipophilic stains, whose log P greater than 2. In keeping with this, use of GMA semi-permeable membranes for enzyme histochemistry failed to give staining when using a lipophilic substrate, probably because the substrate was trapped in the membrane. An analysis of other routine histochemical stains--in terms of the probable occurrence of high resin background staining and low tissue sensitivity--is made. A numerical guide is provided to help avoid artefacts resulting from hydrophobic and size effects. Note: small, hydrophilic reagents (log P less than 0; molecular weight less than 550 Da) are least likely to show either type of artefact. Conversely, reagents which are lipophilic, or/and of intermediate size (log P greater than 2; 550 less than ionic weight less than 1000 Da), give strong background staining.

Animals↗
PubMed1992

Deficiency of 17 alpha-hydroxylase associated with absent gonads.

A phenotypic female presented initially at the age of 17 years with amenorrhoea and delay of sexual development. Karyotype was male, 46 XY, and as gonads were absent, a diagnosis of congenital anorchia was made. The patient was treated with oestrogen. At the age of 23 years, she re-presented with tall stature and hypertension. She then had normal female habitus but absent pubic and axillary hair. Re-investigation showed that sex steroids and cortisol were absent and established the diagnosis as 17 alpha-hydroxylase deficiency. Treatment with hydrocortisone rapidly corrected the hypertension. Ultrasound examination confirmed the absence of gonads but showed that a small uterus was present. Measurement of serum cortisol is important for recognition of such patients, but further measurements of sex steroids, particularly progesterone, are needed to prove the diagnosis. We have found no previous reports of absent gonads in 17 alpha-hydroxylase deficiency. The association remains unexplained.

Adolescent↗
PubMed1992

Acute iron intoxication in pregnancy: case report and review of the literature.

Limited reports exist regarding acute iron intoxication during pregnancy. The maternal and fetal effects of accidental or deliberate ingestion of large amounts of iron may be catastrophic. A case report of acute iron intoxication, management strategies, and a review of the literature are presented. The cornerstones of effective therapy are aggressive management with emesis induction or gastric lavage, bicarbonate instillation, vigorous intravenous hydration, and chelation therapy with deferoxamine.

Adolescent↗
PubMed1992

Lyme disease in Ireland.

The data pertaining to Irish specimens sent to the Lyme disease Laboratory at Charing Cross Hospital since 1986 is presented and discussed. In the period up to June 1990, 484 specimens were tested, 14% of these were positive by enzyme linked immunosorbent assay or indirect immunofluorescent assay. Only 13 of these were confirmed as positive by immunoblotting.

Adult↗
PubMed1991

Distribution and developmental expression of the nerve terminal protein NT75 in the rat cerebellum.

Previous studies of the nerve terminal protein NT75 in the developing spinal cord have suggested an association between the appearance of NT75 immunoreactivity and the process of synaptogenesis. To examine the time course of NT75 expression further, the current study compared the localization of NT75 and the synaptic vesicle protein synaptophysin in the adult and developing rat cerebellum and in cerebellar tissue cultures. In the adult cerebellum, dense NT75 staining is confined to the molecular layer, where it is associated with parallel fiber endings of cerebellar granule cells. During development, NT75 immunoreactivity is first detectable in the cerebellar cortex as a dense band of staining in the deepest portion of the molecular layer at postnatal day 10. The stained zone expands to occupy a progressively greater portion of the molecular layer until about postnatal day 20. Synaptophysin staining occurs in granule cell processes earlier than NT75 and is found throughout the molecular layer by postnatal day 7. Quantitatively, rapid increases in both NT75 and synaptophysin occur in the first three postnatal weeks, with NT75 activity reaching levels exceeding the adult value by 50% over postnatal days 20 through 30, whereas synaptophysin plateaus at near adult levels by postnatal day 20. In cerebellar cultures, NT75 staining in neurites develops over several days, increasing coincidentally with development of synaptic contacts, whereas synaptophysin staining is already present in most neurites after only 1 day in vitro. The results indicate that NT75 expression in developing cerebellar granule cell nerve terminals is closely associated with the appearance of mature nerve terminals, suggesting that the protein may have a role in the formation/stabilization of the synaptic ending or in the mechanisms of synaptic transmission.

Animals↗
PubMed1991

Management of infected aortoiliac aneurysms.

A 30-year retrospective review identified 13 patients treated for infected aneurysms of the abdominal aorta or iliac arteries, for an overall incidence of 0.65%. A constellation of clinical findings led to the correct preoperative diagnosis in 11 (85%) of 13 patients. Treatment methods included resection and in situ replacement grafting in seven patients, resection and extra-anatomic bypass in five patients, and resection-ligation in one patient. Four (31%) of 13 patients died within 30 days of operation, three of whom died of rupture. Overall, good results were achieved in five patients (38%), while poor results were noted in the remaining eight patients (62%). The determinants of outcome were aneurysm location or rupture, the presence of established infection, and the virulence of the infecting organism. In 10 (77%) of the 13 aneurysms, Salmonella species, Bacteroides fragilis, Staphylococcus aureus, and Pseudomonas aeruginosa accounted for all deaths, ruptures, and suprarenal aneurysm infections. These data suggest that patients with primary infections of the abdominal aorta or iliac arteries continue to present with advanced infections or aneurysm rupture that result in a high mortality.

Adult↗
PubMed1991

Prenatal diagnosis of duplication cyst of the pylorus.

The first description of the antenatal appearance of a duplication cyst of the pylorus is presented. Prior to the infant's delivery, the possibility that this intra-abdominal cystic mass represented a choledochal cyst was also strongly considered. The antenatal detection of this cystic mass allowed close neonatal surveillance and timely surgical intervention prior to the onset of serious neonatal complications. The embryogenesis of duplication cysts of the gastrointestinal tract and bronchopulmonary foregut malformations is reviewed. The clinical utility of the prenatal diagnosis of such fetal gastrointestinal anomalies is also discussed.

Adult↗
PubMed1991

Randomized, double-blind trial of deflazacort versus prednisone in juvenile chronic (or rheumatoid) arthritis: a relatively bone-sparing effect of deflazacort.

Thirty-four children with juvenile chronic (rheumatoid) arthritis were recruited to a randomized, double-blind study of deflazacort (an oxazolone derivative of prednisone) vs prednisone. All had been receiving glucocorticoid therapy for at least 1 year and required at least 5 mg/d of prednisolone (usually as 10 mg every 2 days). Thirty-one children completed the study. Bone density trends were measured in the spine by dual photon absorptiometry and in the forearm by single photon quantitative computed tomography at 3-monthly intervals. Trends (velocities) in bone and soft tissue growth were calculated. In the spine, bone growth correlated well with indices of soft tissue growth, but covariance analysis showed a significant advantage (P less than .007) of deflazacort when spinal bone mineral growth was compared to body surface area and weight. In part this was due to a temporary interruption in weight by children receiving deflazacort, whose gain in height was comparable with that of the prednisone group. Some children in both groups improved clinically and showed catch-up growth; in these children relative spinal bone mineral growth velocities were about twice those observed for height and weight. It is concluded that during the first year of deflazacort, their spinal bone mineral content at a level that was appropriate for their height and weight. Further observations are required to establish whether this advantage can be maintained subsequently. The anti-inflammatory effects of the two glucocorticoids appeared similar.

Adolescent↗
PubMed1990

Computer-assisted interpretation of 1H-n.m.r. spectra in the analysis of the structure of oligosaccharides.

A computer program that can be implemented on IBM compatible microcomputers has been used to interpret the 1H-n.m.r. spectra of a series of mucin-derived alditols. The program compares the chemical shifts of resonances in the spectra of unknown oligosaccharides with those in a standard library constructed from data in the literature. The program then compiles the identified sequences into possible structures, which, together with a second component of the program from which the individual assignments of chemical shifts can be made, facilitates ready access to the literature data for final confirmation of the structures.

Carbohydrate Sequence↗
PubMed1990

High performance liquid chromatographic studies of erythrocytes haem biosynthetic enzyme activities in alcoholic macrocytosis.

The activities of 5-aminolaevulinate dehydrase (ALA-D), hydroxymethylbilane synthase (HMB-S), uroporphyrinogen III synthase (URO-S) and uroporphyrinogen decarboxylase (URO-D) in the erythrocytes of alcoholics were assayed and compared with those in controls and abstaining alcoholics. The HMB-S and URO-S activities in alcoholics were significantly higher than the controls and there were significant correlations between enzyme activities and mean corpuscular volume (MCV). Alcoholics abstaining from alcohol over a nine-month period showed a return to normal enzyme activities in parallel with the normalization of their MCV. Abstaining alcoholics thus all had normal HMB-S and URO-S activities. The ALA-D and URO-D activities of alcoholics were not significantly different from controls or from abstaining alcoholics. Alcohol appears to have a selective effect on the haem biosynthetic enzymes in the erythron.

Adult↗
PubMed1990

Pitfalls in lower extremity venous duplex scanning.

Results of scans performed on 1074 patients over an 18-month period were evaluated to define the limitations of lower extremity venous duplex scanning. Eighty-four patients had confirmatory phlebography performed within 24 hours of their venous duplex scanning. In 71 patients scans were considered diagnostic (sensitivity 91%, specificity 95%). Eighteen studies (13 equivocal, 5 misinterpretations) were scrutinized to determine the limitations of venous duplex scanning compared to phlebography and are the focus of this analysis. Seven patients had phlebograms documenting only infrapopliteal thrombus, seven had normal phlebographic findings, and four had findings consistent with chronic thrombosis. In the seven patients with infrapopliteal thrombus, four had normal imaging outcomes but abnormal Doppler flow patterns, whereas three had both normal imaging results and flow patterns. All four patients with chronic thrombosis had identifiable thrombus and abnormal flow patterns by venous duplex scanning, but in each case thrombus age was indeterminate. Of the seven patients with normal phlebographic results, five had incompressible segments of the superficial femoral vein on imaging, one had abnormal Doppler flow without visualized thrombus and without apparent reason, one had venous duplex scanning visualized thrombus with a normal outcome on phlebography. These data suggest that the diagnostic yield of lower extremity venous duplex scanning may be improved by (1) meticulous infrapopliteal vein examination, (2) better estimation of the age of the thrombotic process, and (3) recognizing segmental incompressibility of the superficial femoral vein within the adductor canal as a normal finding especially in the absence of abnormal Doppler flow or imaged thrombus.

Chronic Disease↗
PubMed1990

Characterization of an rRNA gene-specific cDNA probe: applications in bacterial identification.

Discontinuous DNA complementary to Escherichia coli 16S + 23S ribosomal RNA was synthesized by random oligonucleotide priming using reverse transcriptase. cDNA generated from native or denatured rRNA template was labelled by incorporation of either [alpha-32P]dCTP or digoxigenin-labelled dUTP during synthesis, followed by template hydrolysis. The specific activity of the radiolabelled cDNA was 10(7)-10(8) c.p.m. (micrograms rRNA template)-1 with 60-92% incorporation after 5 h. The length of the reverse transcript was between 20 and 1140 nucleotides and was unaffected by exclusion of primer. The cDNA probe could detect 3 pg rRNA by quantitative slot blot. In the non-radiolabelling digoxigenin system 3 micrograms template gave 0.5-2.0 micrograms cDNA after 24 h with a length of between 100 and 1225 bases. This probe could detect 50 pg rRNA. Probes were evaluated in the comparison of Pasteurella haemolytica biotypes by hybridization to Southern blots of restriction-endonuclease-digested total DNA. The digoxigenin-labelled probe was used to identify clinical isolates of Campylobacter jejuni to demonstrate its potential use in laboratories requiring high-sensitivity detection without the use of radioisotopes.

Alkaline Phosphatase↗
PubMed1990

Flumazenil in the outpatient. A study following midazolam as sedation for upper gastrointestinal endoscopy.

Fifty outpatients who underwent upper gastrointestinal endoscopy under midazolam sedation were allocated randomly into two equal groups of 25 in this double-blind study. After the endoscopy, and 30 minutes after administration of the sedative, patients in one group received flumazenil 0.5 mg; those in the other group received a similar volume of vehicle only. Assessments of memory function, psychomotor performance and coordination were carried out and these were repeated 3.5 hours later. Flumazenil produced a significant improvement (p less than 0.001) immediately but no difference could be detected between flumazenil and placebo at 3.5 hours. However, patients in the flumazenil group reported, by means of linear analogue scales, a subjective feeling of alertness at the time of discharge, which was greater than that reported by those in the placebo group (p less than 0.005).

Adolescent↗