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Biomedical subjects

D R James

Publications and source records attributed to D R James.

At least 37 records · Page 2Linked to original sources
PubMed1991

Kinetics of a rapid, luminol dependent chemiluminescence signal induced in HL-60 cells by amphotericin B and other stimulants.

Addition of the polyene antibiotic amphotericin B or tissue culture medium to nondifferentiated HL-60 cells in the presence of luminol induces a chemiluminescence signal that reaches a peak value within a few seconds and decays exponentially in less than a minute. The kinetics of the signal and its modulation by superoxide dismutase, catalase, and horseradish peroxidase are consistent with a series of solution biochemical processes with a rate-determining step corresponding to the disproportionation of a luminol-superoxide complex. The effects of the enzymes demonstrate that superoxide is a precursor to the rate-determining intermediate and that both catalase and peroxide enhance a reaction that competes with the rate-limiting process.

Amphotericin B↗
PubMed1990

Mandibular reconstruction using vascularised fibula.

The osteocutaneous fibula flap has been used to reconstruct large segments of mandible in cases following ablation for cancer or radionecrosis. The bone can be cut to the appropriate shape and the fasciocutaneous flap may be used simultaneously to provide oral cavity lining or skin cover. The technique is described and its successful use in seven patients is reported with details of the complications encountered.

Adult↗
PubMed1990

The Sri Lankan Cleft Lip and Palate Project: the unoperated cleft lip and palate.

Since 1984, the Sri Lankan Cleft Lip and Palate Project has developed a large surgical and research program collecting records on over 500 subjects with unrepaired cleft lip and palate. In addition, 410 operations were performed by Project and will be followed by individual reports on facial growth and morphology, speech, surgical and anesthetic aspects, and the otologic significance of cleft palate in this issue and subsequent ones.

Adolescent↗
PubMed1989

Le Fort I maxillary osteotomies in cleft palate cases. Surgical changes and stability.

Surgical and postsurgical changes in maxillary position following transpalatal osteotomy at the le Fort I level in 30 patients with clefts of lip and palate were evaluated cephalometrically. By superimposing on natural reference structures, a more accurate and detailed evaluation of change in maxillary position was possible than by using conventional cephalometric analyses. The mean horizontal advancement was 9 mm, with a mean vertical change of 3 mm. While it is customary to express postsurgical relapse as a percentage of surgical change (in this case 7% mean horizontal relapse and 23% mean vertical relapse), the most remarkable finding to emerge from this study was the variability in surgical and postsurgical change which would be obscured by concentrating on descriptive statistics. Postsurgical change was related to the amount of surgical change, but the correlation coefficients are quite low, and so other factors must be responsible for a significant proportion of any relapse.

Adolescent↗
PubMed1989

Surgical correction of temporomandibular joint ankylosis.

A better understanding of facial growth processes and pathophysiology of temporomandibular joint ankylosis should lead to an improved surgical outcome. Surgical anatomy, pathophysiology, and treatment options are reviewed. Suggestions for varying the procedure in patients in whom facial growth is not complete are discussed.

Ankylosis↗
PubMed1987

Distributions of fluorescence decay times for parinaric acids in phospholipid membranes.

Analysis of fluorescence decay data for probes incorporated into model or biological membranes invariably requires fitting to more than one decay time even though the same probe exhibits nearly single-exponential decay in solution. The parinaric acids (cis and trans) are examples of this. Data are presented for both parinaric acid isomers in dimyristoylphosphatidylcholine membranes collected to higher precision than normally encountered, and the fluorescence decays are shown to be best described by a smooth distribution of decay times rather than by a few discrete lifetimes. The temperature dependence of the fluorescence decay reveals a clear shift in the distribution to longer lifetimes associated with the membrane phase transition at 23.5 degrees C. The physical significance is that fluorescence lifetime measurements appear to reflect a physical process with a distribution of lifetimes rather than several distinct physical processes.

Dimyristoylphosphatidylcholine↗
PubMed1987

Reconstruction of the middle third of mandible.

The radial forearm flap is established as a suitable method of providing bone with soft tissue lining or skin cover in reconstruction of the mandible. A simple and effective method of modelling the radius to provide the appropriate contour to the anterior arch of the mandible is described.

Humans↗
PubMed1987

Maxillary myxoma in a child of 11 months. A case report.

A myxoma of the maxilla in an infant is presented. It was initially treated as an inflammatory lesion. Failure to respond led to biopsy, which showed that the lesion was neoplastic; initially an incorrect diagnosis was made and totally inappropriate treatment was given. Reassessment of the biopsy material established the correct diagnosis and appropriate management was initiated.

Combined Modality Therapy↗
PubMed1987

Familial pseudohyperkalaemia: inhibition of erythrocyte K+ efflux at 4 degrees C by quinine.

1. Mechanisms responsible for increased erythrocyte K+ efflux in vitro have been investigated in a patient with familial pseudohyperkalaemia. Mean net K+ efflux (4 degrees C) was 108 nmol h-1 10(-9) erythrocytes, seven times greater than the mean for controls (15.2 nmol h-1 10(-9) erythrocytes). Net K+ efflux was not increased at 22 degrees C or 37 degrees C and losses at 4 degrees C were reversed by subsequent incubation at 37 degrees C. 2. Erythrocyte glucose consumption (4 degrees C) was 14 nmol h-1 10(-9) erythrocytes, similar to the mean for controls of 16.8 nmol h-1 10(-9) erythrocytes. This suggests that the increased net K+ efflux (4 degrees C) was not associated with abnormal energy consumption and was therefore unlikely to be due to an abnormality of the Na+, K+-pump. 3. Incubation of erythrocyte suspensions with ouabain (0.1 mmol/1) or frusemide (1 mmol/1) at 4 degrees C or 37 degrees C resulted in no differences in K+ efflux between patient and controls. Incubation with quinine (2 mmol/1), an inhibitor of the erythrocyte Ca2+-dependent K+ channel, reduced net K+ efflux at 4 degrees C, but the effect persisted in Ca2+-depleted erythrocytes, implying that quinine was acting in a non-specific fashion. 4. Chemical pathologists and clinicians must be aware of this condition if inappropriate treatment of pseudohyperkalaemia is to be avoided.

Erythrocytes↗
PubMed1987

Development at Cold-Hardening Temperatures : The Structure and Composition of Purified Rye Light Harvesting Complex II.

Light harvesting complex II (LHCII) was purified from cold-hardened (RH) and nonhardened winter rye (RNH) (Secale cereale L. cv Puma) employing a modified procedure of JJ Burke, CL Ditto, CJ Arntzen (Arch Biochem Biophys 187: 252-263). Triton X-100 solubilization of thylakoid membranes followed by three successive precipitations with 100 mm KCl and 10 mm MgCl(2) resulted in yields of up to 25% on a chlorophyll (Chl) basis and a purity of 90 to 95%, based on polypeptide analysis within 4 hours. Polypeptide and pigment analyses, 77 K fluorescence emission and room temperature absorption spectra indicate the LHCII obtained by this modified method is comparable to LHCII obtained by other published methods. Comparison of purified RH and RNH LHCII indicated no significant differences with respect to polypeptide, amino acid, Chl, and carotenoid compositions as well as no differences in lipid content. However, RH LHCII differed from RNH LHCII specifically with respect to the fatty acid composition of phosphatidyldiacylglycerol only. RH LHCII exhibited a 54% lower trans-Delta(3)-hexadecenoic acid level associated with PG and a 60% lower oligomeric LHCII:monomeric LHCII (LHCII(1):LHCII(3)) than RNH LHCII. Both RH and RNH LHCII exhibited a 5-fold enrichment in PG specifically. Complete removal of PG by enzymic hydrolysis resulted in a significant reduction in the oligomeric content of both RH and RNH LHCII such that LHCII(1):LHCII(3) of RH and RNH LHCII preparations were the same. This confirms that this specific compositional change accounts for the structural differences between RH and RNH LCHII observed in situ and in vitro.

Journal Article↗
PubMed1987

Reflotron assays of alanine aminotransferase and gamma-glutamyltransferase in whole-blood samples evaluated.

We evaluated the Reflotron (Boehringer Mannheim) system for measuring activities of alanine aminotransferase (EC 2.6.1.2) and gamma-glutamyltransferase (EC 2.3.2.2). Within- and between-day precision were comparable with conventional analytical methods. The linear range of the methods extended to more than 40-fold the upper limit of the reference range. The methods were not influenced by moderate changes in blood rheology and also tolerated some variation in sample volume applied. We consider these methods to be suitable for use in satellite or physicians' office laboratories (with appropriate training of operators), and they can produce results that agree satisfactorily with those determined in routine laboratory practice.

Alanine Transaminase↗
PubMed1986

Prosthetic graft infection: limitations of indium white blood cell scanning.

The lack of a rapid, noninvasive, and accurate method to confirm or rule out prosthetic graft infection continues to constitute a compelling and vexing clinical problem. A host of adjunctive diagnostic techniques has been used in the past, but early promising results subsequently have usually not yielded acceptable sensitivity (reflecting false negatives) and specificity (reflecting false positive) data. White blood cell (WBC) indium 111 scanning has recently been added to this list. The utility and accuracy of 111In WBC scans were assessed by retrospective review of WBC scan results in 70 patients undergoing evaluation for possible prosthetic graft infection over a 7-year period. Operative and autopsy data (mean follow-up, 18 months for survivors with negative scans) were used to confirm the 22 positive, 45 negative, and three equivocal WBC scans. The false positive rate (+/- 70% confidence limits) was 36% +/- 6% (n = 8) among the 22 patients with positive scans (44% +/- 6% [11 of 25] if the three equivocal scans are included as false positive), yielding a specificity of 85% +/- 5% and an overall accuracy rate of 88% +/- 4% (80% +/- 5% and 84% +/- 5%, respectively, if the three equivocal cases are considered as false positive). All three patients with equivocal scans ultimately were judged not to have prosthetic graft infection. As implied by the high accuracy rate, the sensitivity of the test was absolute (100% [14 of 14]); there were no false negative results. (ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗