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L J Russell

Publications and source records attributed to L J Russell.

11 recordsLinked to original sources
PubMed1992

Pro-oxidant effects of lipoxygenase-derived peroxides on the copper-initiated oxidation of low-density lipoprotein.

It has been proposed that lipoxygenases, specifically 15-lipoxygenase, may play an important role in promoting the oxidation of low-density lipoprotein (LDL) in the artery wall. It is well known that peroxides are unstable in the presence of transition metals, decomposing to form the alkoxy and peroxy radicals, and so initiating lipid peroxidation. To test whether lipoxygenase-derived peroxides may promote the oxidation of LDL in the presence of copper, the lipoprotein was enriched with lipid peroxides derived from the enzymic action of 5- and 15-lipoxygenases on either linoleic or arachidonic acid. All of these products were found to promote oxidation, whereas the related hydroxy fatty acids had no effect. This suggests that lipoxygenase-derived peroxides associated with the LDL particle may promote peroxidation in the presence of a suitable transition metal catalyst. This result has implications both for the mechanism of the potential pro-oxidant action of lipoxygenases in vivo and for the ex vivo assessment of the oxidizability of LDL samples isolated from different donors.

Arachidonic Acid↗
PubMed1991

Partial duplication of the face: case report and review.

Complete or partial facial duplication is a rare congenital malformation. A spectrum of structural abnormalities varying in degrees of severity has been described in affected individuals. We present discordance for facial duplication between monozygotic twins in which maxillary and mandibular duplication was present in one. The involved twin showed the following findings: ocular hypertelorism, bifidity of the nose, duplication of the maxilla, macrostomia, cleft of the lower lip, hamartoma of the vomer, supernumerary teeth, duplication of the mandibular teeth, bifidity of the tongue, and hamartoma of the floor of the mouth. Surgical management of the facial anomalies is discussed. A review of the literature and discussion of this rare malformation are presented.

Cleft Palate↗
PubMed1991

The pinworm, Enterobius vermicularis.

The pinworm, Enterobius vermicularis, is the most common intestinal parasite in the primary care setting, regardless of race, socioeconomic or cultural circumstances. This article discusses symptoms, diagnosis, and treatment.

Animals↗
PubMed1989

Ivemark's "asplenia" syndrome: a single gene disorder.

Congenital heart defects as a group represent a significant proportion of congenital malformations. Most are isolated and multifactorially determined; a relatively small proportion are due to a single gene defect, and result in an increased risk of recurrence among first-degree relatives. We have reported the cases of three male siblings with Ivemark's "asplenia" syndrome to support an autosomal recessive mode of inheritance. We have stressed the importance of early recognition of mendelian disorders with associated cardiac malformations to provide meaningful counseling regarding prognosis, medical management, and risk of recurrence.

Adult↗
PubMed1989

Gastrocolic fistula presenting as acute diarrhea.

Abdominal pain, diarrhea, weight loss, vomiting, foul eructation, feculent vomiting and melena are among the presenting symptoms of patients with a gastrocolic fistula. A routine physical examination is useful in ruling out the more common causes of the presenting complaints. Barium enema shows the gastrocolic fistula in 90 to 100 percent of cases. En bloc resection of the stomach and colon is the treatment of choice. Alternative therapies include a temporary diverting colostomy, total parenteral nutrition and antacid therapy.

Adult↗
PubMed1988

Plasma sodium and potassium measurement: minimising ISE-flame differences using specimens from patients.

Experience in clinical chemistry of direct reading ion-selective electrode analysers for the measurement of plasma Na+ and K+ concentrations has shown that the results obtained on any specimen may vary significantly from one make of instrument to another. To overcome these differences, the European Working Group on ISEs of the IFCC Expert Panel on pH, Blood Gases and Electrolytes have proposed that instruments should be standardised to report Na+ and K+ concentrations in undiluted plasma to agree with flame emission spectrometry in samples with normal plasma water bicarbonate concentrations and normal pH. In designing and setting the calibration of a new ISE analyser for Na+ and K+, the Corning 614, the manufacturer has attempted to satisfy this proposal using a large number of specimens obtained from patients. This paper presents details of the procedure used and the results of an independent evaluation of its validity in routine clinical practice.

Electrodes↗
PubMed1986

The commercialisation of sensor technology in clinical chemistry: an outline of the potential difficulties.

Despite the numerous examples in the research literature of the potential application of biosensors in clinical chemistry, very few have reached commercialisation. Many pitfalls await the potential manufacturer of bioprobes in clinical chemistry and key areas which require substantial development are: reproducibility of sensor manufacture; interaction of the sensor with appropriate hardware; evaluation and customer perception. This paper discusses and illustrates these problems with examples taken from the recent introduction of ion-selective electrode analysers in regular clinical use. Many similar problems are envisaged for the commercialisation of biosensors and extensive collaboration is essential between researchers, manufacturers and users to overcome the difficulties.

Biotechnology↗
PubMed1985

Ion-selective electrode technology: an overview.

Diluting a sample before analysis, as is required by both flame photometry and indirect reading ISE analysers, gives less relevant analytical results than measuring an undiluted sample directly. This is because dilution masks the impact that protein and lipids exert on the true activity of an ion in a clinical sample. Measuring a sample directly without dilution enables only those ions which are not bound to other materials, e.g. other ions or proteins, to be detected. The levels of these free ions are more likely to reflect true physiological status than analysis of both free and bound ions. Measuring a sample of whole blood directly without dilution can only be performed accurately if the ISE analyser reference junction is unaffected by changes in haematocrit. Calibrant compositions should be of an ionic strength similar to that of physiological samples. Residual liquid junction potentials between calibrants and samples should be minimised by careful design of the reference electrode.

Autoanalysis↗