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Biomedical subjects

P Jones

Publications and source records attributed to P Jones.

At least 325 records · Page 18Linked to original sources
PubMed1991

Evidence for the generation of hydroxyl radicals from a chromium(V) intermediate isolated from the reaction of chromate with glutathione.

The formation of hydroxyl radicals from a chromium(V) complex isolated from the reaction of glutathione with chromate has been demonstrated in spin trapping experiments using dimethylsulfoxide and 3,5-dibromo-4-nitrosobenzene sulfonate. Mechanisms for the formation of radicals in such systems are discussed. These results help to explain the ability of solutions containing chromate and glutathione to cause strand breaks in DNA.

Chromates↗
PubMed1991

Fetal brain development and later schizophrenia.

Computed tomography and magnetic resonance imaging studies have shown cerebral ventricular enlargement and a decreased volume of temporal lobe structures in a proportion of schizophrenic patients. Neuropathological investigations confirm these findings and also show diminished volume of the hippocampus and abnormal pre-alpha cell clusters in the parahippocampal gyrus. Compared with controls, schizophrenic patients are more likely to have minor physical anomalies, to have a history of obstetric complications, and to have been born in the late winter. Together the evidence regarding structural brain abnormalities and epidemiology suggests that a significant proportion of cases of schizophrenia have their origins in fetal or neonatal life. The mechanisms involved in the aberrant neurodevelopment remain obscure but some impairment of neuronal migration is an appealing hypothesis.

Brain↗
PubMed1991

Chemometrics in pharmaceutical analysis.

Pharmaceutical analysis is undergoing a slow revolution as chemometric principles become increasingly incorporated. This paper reviews some of the more recent advances, with particular focus on spectrophotometry, chromatography and expert systems.

Biometry↗
PubMed1991

Identification of a high risk subgroup of grade 1 transitional cell carcinoma using image analysis based deoxyribonucleic acid ploidy analysis of tumor tissue.

The use of deoxyribonucleic acid (DNA) cytometry to identify a subset of patients with grade 1, stage Ta or T1 transitional cell carcinoma at high risk for death or recurrence was investigated in a retrospective study using paraffin blocks from 88 low grade transitional cell carcinomas of the bladder with an absorptiometric video-based image analysis system. Tumors were evaluated for ploidy (70 diploid, 16 aneuploid and 2 tetraploid) and the presence of cells with greater than 5C DNA. Survival analysis of 62 patients with adequate followup (15 to 20 years) showed that 43 of 62 (69%) suffered recurrences and 13 (21%) died of bladder cancer. The single most important predictors of death and recurrence were stem line aneuploidy and the presence of cells with greater than 5C DNA, respectively.

Carcinoma, Transitional Cell↗
PubMed1991

The human glutathione S-transferases: a case-control study of the incidence of the GST1 0 phenotype in patients with adenocarcinoma.

The suggestion that individuals with the GST1 0 phenotype have a greater susceptibility to carcinogens than those with other GST1 phenotypes has been examined by using a starch gel zymogram approach to compare the frequency of this phenotype in control subjects and a group of patients with adenocarcinoma of stomach and colon. A significantly greater proportion of the patients with adenocarcinoma demonstrated the null phenotype, odds ratio analysis indicating that individuals with this polymorphic variant have an approximately 3-fold greater risk of developing these cancers.

Adenocarcinoma↗
PubMed1991

Hepatitis C antibody profile and viraemia prevalence in adults with severe haemophilia.

Sera from 21 patients who had received large amounts of unheated factor VIII concentrate were tested for antibodies to the hepatitis C virus (HCV) by both commercial (Ortho C100) and 'in house' ELISAs. 'In house' assays utilized recombinant structural (core) or non-structural (replicase) HCV proteins generated by a baculovirus expression system. Antibodies to HCV were detected in 100% of the sera by the core protein based ELISA but in only 62% and 19% by the C100 and replicase based ELISAs, respectively. Hepatitis C viraemia was demonstrated in 90% of the patients by in vitro amplification of the 5' non-coding region of the HCV genome. Amplification with primer sets from two other regions of the genome proved less efficient at detecting viraemia. We conclude that the prevalence of hepatitis C infection in haemophiliacs may have been underestimated previously and that almost all HCV-infected patients have evidence of on-going viral replication.

Adult↗
PubMed1991

[Radiology and radioprotection in dental medicine. 2: Regulations and practical recommendations].

The three general principles of the International Commission on Radiological Protection (ICRP) are first recalled: (1) justification, (2) ALARA, (3) the dose limits. The dose limits to be followed, at present, in Belgium are given for the occupational exposure, the occupational exposure of women (pregnant and not), the exposure of the public. The possible modification of the dose limits by the ICRP is a near future is discussed. The present belgian regulations are reviewed as far as the equipment and the buildings are concerned, as well as for the personal dosimeters and the medical supervision. Finally, the doses delivered to the patients, at different organs, during dental radiological examinations are recalled, e.g. the doses at the skin, the thyroid, the gonads, the eyes, the pituitary gland. The interest of shielding the thyroid and the abdomen is discussed.

Belgium↗
PubMed1991

Human ehrlichiosis diagnosed in Wisconsin.

A man developed a febrile illness shortly after he returned to Wisconsin from Florida, where he had received tick bites. This illness was associated with a rash, thrombocytopenia, leukopenia, and elevated hepatic enzymes, and it resolved on doxycycline. Serologic studies confirmed ehrlichiosis, a tick-borne rickettsial intraleukocytic infection endemic to the Southeastern United States. This case expands the spectrum of tick-borne illnesses that must be considered by Wisconsin clinicians.

Adult↗
PubMed1990

Human glutathione S-transferases: radioimmunoassay studies on the expression of alpha-, mu- and pi-class isoenzymes in developing lung and kidney.

The developmental expression of the alpha-, mu- and pi-class glutathione S-transferases has been defined in human lung and kidney using radioimmunoassay, immunohistochemistry and column chromatography. Expression of alpha-class enzymes increased significantly after about 40 weeks gestation in kidney but not lung, while expression of mu isoenzymes was continuous throughout development in both tissues. Expression of the pi isoenzyme fell during in utero ontogeny in lung, the pattern of down-regulation being similar to that previously observed in liver. There was no change in the expression of this isoenzyme in kidney. Comparison of the expression of the glutathione S-transferases in developing lung, kidney and liver shows some common patterns of expression suggesting these genes are under similar regulatory control.

Down-Regulation↗
PubMed1990

Does 3,5,dibromo-4-nitrosobenzene sulphonate spin trap superoxide radicals?

Pulse radiolysis studies show that the spin trap 3,5,dibromo-4-nitrosobenzene sulphonate (I) reacts rapidly with O2.- but the product formed is very unstable. No radicals were detected in ESR studies of solutions of I after reaction with O2.- formed by gamma-radiolysis. Evidence is presented that the stable radical observed by some, but not all workers, following exposure of I to the O2.(-)-generating xanthine/xanthine oxidase system, is produced by a peroxidatic oxidation using hydrogen peroxide formed by O2-. dismutation and that formation of this radical depends on the presence of peroxidase activity in the xanthine oxidase sample employed.

Benzenesulfonates↗