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Biomedical subjects

J Laidlaw

Publications and source records attributed to J Laidlaw.

At least 19 recordsLinked to original sources

Dietetic guidelines: diet in secondary prevention of cardiovascular disease (first update, June 2003).

AIM: To update dietetic guidelines summarizing the systematic review evidence on dietary advice to prevent further events in people with existing cardiovascular disease (CVD) (secondary prevention). METHODS: The Cochrane Library, MEDLINE and EMBASE were comprehensively searched to November 2002 for systematic reviews on aspects of diet and heart health. Reviews were included if they searched systematically for randomised controlled trials relating to diet and secondary prevention of CVD. Two members of the UK Heart Health and Thoracic Dietitians Group critically appraised each review. The quality and results of each review were discussed and summarized in a meeting of the whole group. RESULTS: Providing evidence-based dietary information (including increasing omega-3 fat intake) to all people who have had a myocardial infarction will save more lives than concentrating dietary advice on just those in need of weight loss or lipid lowering. The practice of prioritizing dietetic time in secondary prevention to those with raised lipids is out of date since the advent of statin therapy. However, effective dietary advice for those with angina, stroke, peripheral vascular disease or heart failure is less clear. CONCLUSION: There is good systematic review evidence that dietary advice to those with coronary heart disease can reduce mortality and morbidity as well as modify some risk factors. Dietary advice that does this most effectively should be prioritized.

Cardiovascular Diseases↗

PA26, a novel target of the p53 tumor suppressor and member of the GADD family of DNA damage and growth arrest inducible genes.

Exposure of mammalian cells to hypoxia, radiation and certain chemotherapeutic agents promotes cell cycle arrest and/or apoptosis. Activation of p53 responsive genes is believed to play an important role in mediating such responses. In this study we identified a novel gene, PA26, which maps to chromosome 6q21 and encodes at least three transcript isoforms, of which two are differentially induced by genotoxic stress (UV, gamma-irradiation and cytotoxic drugs) in a p53-dependent manner. A functional p53-responsive element was identified in the second intron of the PA26 gene, in consistance with a mechanism of transcriptional induction of the PA26 gene by p53. No clues to its functions were revealed by sequence analysis, although pronounced negative regulation by serum factors argues for a potential role of PA26 in growth regulation. Immunological analysis suggests that PA26 protein(s) is localized to the cell nucleus. Our results suggest that the PA26 gene is a novel p53 target gene with properties common to the GADD family of growth arrest and DNA damage-inducible stress-response genes, and, thus, a potential novel regulator of cellular growth.

Alternative Splicing↗

Optimal assessment of cervical spine trauma in critically ill patients: a prospective evaluation.

There is no uniformly accepted protocol for the radiological assessment of the cervical spine in critically ill trauma patients. The Alfred Trauma Centre receives about 40% of Victorian patients with major trauma. A protocol was developed for cervical spine evaluation, comprising three plain X-rays and a swimmer's view added when necessary to visualize C7-T1, CT and/or MRI for abnormal regions, and functional (flexion/extension) X-rays to exclude cervical spine instability due to soft tissue trauma. Functional X-rays were performed "actively" in conscious patients and "passively" in unconscious patients. One hundred consecutive patients were prospectively evaluated and 91 survived to complete data collection. Six (6.6%) had unstable cervical spine injuries--five detected with plain X-rays and one (1.1%) detected only with passive functional X-rays. Static cervical X-rays cost $93.00 per patient. Functional cervical X-rays added $42.00 per patient and were uncomplicated. Collar complications were common when collars remained on for more than 72 hours. This low detection rate is clinically important because of the enormous potential social and economic costs of missed unstable cervical spine fractures.

Adult↗

Benchmarking and supplier networking--best practice approaches.

This article examines the approach adopted by a health service to benchmark outside the health industry and to network with its own suppliers in its quest for best practice. The Maryborough District Health Service was selected for funding under the Commonwealth Government's Best Practice in the Health Sector Program. This rural health service is setting a fine example of how generic benchmarking can be used to increase efficiency and improve outcomes in an environment of change, increasing demands, and contracting resources. The organisation has networked with its suppliers with a view to ensuring that, as a customer, it has access to the best quality goods and services. The objective is to improve the services and quality of patient care provided by the health service and to minimise its cost structures.

Australia↗

Cloning and characterization of a mouse gene with homology to the human von Hippel-Lindau disease tumor suppressor gene: implications for the potential organization of the human von Hippel-Lindau disease gene.

The human von Hippel-Lindau disease (VHL) gene has recently been identified and, based on the nucleotide sequence of a partial cDNA clone, has been predicted to encode a novel protein with as yet unknown functions [F. Latif et al., Science (Washington DC), 260: 1317-1320, 1993]. The length of the encoded protein and the characteristics of the cellular expressed protein are as yet unclear. Here we report the cloning and characterization of a mouse gene (mVHLh1) that is widely expressed in different mouse tissues and shares high homology with the human VHL gene. It predicts a protein 181 residues long (and/or 162 amino acids, considering a potential alternative start codon), which across a core region of approximately 140 residues displays a high degree of sequence identity (98%) to the predicted human VHL protein. High stringency DNA and RNA hybridization experiments and protein expression analyses indicate that this gene is the most highly VHL-related mouse gene, suggesting that it represents the mouse VHL gene homologue rather than a related gene sharing a conserved functional domain. These findings provide new insights into the potential organization of the VHL gene and nature of its encoded protein.

Amino Acid Sequence↗

Germ-line mutations in the von Hippel-Lindau tumor-suppressor gene are similar to somatic von Hippel-Lindau aberrations in sporadic renal cell carcinoma.

von Hippel-Lindau (VHL) disease is a hereditary tumor syndrome predisposing to multifocal bilateral renal cell carcinomas (RCCs), pheochromocytomas, and pancreatic tumors, as well as angiomas and hemangioblastomas of the CNS. A candidate gene for VHL was recently identified, which led to the isolation of a partial cDNA clone with extended open reading frame, without significant homology to known genes or obvious functional motifs, except for an acidic pentamer repeat domain. To further characterize the functional domains of the VHL gene and assess its involvement in hereditary and nonhereditary tumors, we performed mutation analyses and studied its expression in normal and tumor tissue. We identified germline mutations in 39% of VHL disease families. Moreover, 33% of sporadic RCCs and all (6/6) sporadic RCC cell lines analyzed showed mutations within the VHL gene. Both germ-line and somatic mutations included deletions, insertions, splice-site mutations, and missense and nonsense mutations, all of which clustered at the 3' end of the corresponding partial VHL cDNA open reading frame, including an alternatively spliced exon 123 nt in length, suggesting functionally important domains encoded by the VHL gene in this region. Over 180 sporadic tumors of other types have shown no detectable base changes within the presumed coding sequence of the VHL gene to date. We conclude that the gene causing VHL has an important and specific role in the etiology of sporadic RCCs, acts as a recessive tumor-suppressor gene, and appears to encode important functional domains within the 3' end of the known open reading frame.

Adult↗

Selective activation of the N-glycosylation apparatus in uteri by estrogen.

Estrogen rapidly, preferentially and markedly enhances the rate of N-linked glycoprotein synthesis in mouse uteri. In contrast, the rate of glycoprotein turnover is unaffected by the hormone. Estrogen's effect on the expression of mRNA coding for glycoproteins was studied using an in vitro translation-glycosylation system as well as by Northern/slot blot analyses. Both approaches indicated that estrogen did not have a preferential stimulatory effect on the general expression of glycoprotein mRNA. Neither was there a significant change in the relative levels of specific mRNA coding for several N-linked glycoproteins, i.e. laminin B1 and B2, fibronectin, and uvomorulin, as a function of estrogen treatment. Immunoprecipitation studies also demonstrated no change in the relative rates of synthesis of the corresponding core proteins for laminin or fibronectin. Taken together, these results suggested that estrogen primarily stimulated glycoprotein synthesis by stimulating the glycosylation apparatus, and not by increasing synthesis of protein acceptors. Previous studies have indicated that of a variety of potential regulatory points in the pathway of N-linked glycoprotein assembly, only expression of mannosylphosphoryldolichol synthase (MPDS) increases sufficiently to account for the increase in glycoprotein expression observed in response to estrogen. Consistent with these observations, it was found that injection of uterine poly(A+) RNA from estrogen-treated uteri into Xenopus oocytes markedly stimulated MPDS activity in the oocytes. In contrast, injection of RNA from non-estrogen-treated uteri did not stimulate MPDS activity in oocytes. Collectively, these results indicate that steroid hormones can modulate glycoprotein expression by preferentially stimulating the glycosylation apparatus. Nonetheless, one of estrogen's effects on the glycosylation apparatus, induction of MPDS activity, appears to occur at a transcriptional level.

Animals↗

Effect of carbamazepine on psychomotor performance in näive subjects.

The effect of a single dose of carbamazepine (CBZ), 10 mg kg-1, on a battery of simple psychomotor tests was investigated in 12 healthy subjects (6 male, 6 female) in a balanced randomised double blind placebo controlled cross-over study. Psychomotor testing and blood sampling for total and free plasma CBZ, and CBZ 10, 11 epoxide concentration were performed at 10, 12, 14, 16, 18 and 34 h after oral dosing (23.00 h the previous evening). CBZ impaired i) critical flicker fusion threshold frequency at all time points up to 18 h (p less than 0.005); ii) total choice reaction time at 10 h (p less than 0.005) and 18 h (p less than 0.008); iii) card sorting at 14 h (p less than 0.001). No significant effect on finger tapping was noted. Subjects adjudged themselves more sedated on CBZ as compared to placebo at 12, 14 and 16 h (p less than 0.008). Plasma total and free CBZ concentrations (mean +/- SD) peaked at 10 h (8.8 +/- 0.2 mg 1-1) and 16 h (1.88 +/- 0.3 mg 1-1) after dosing respectively. CBZ 10, 11 epoxide values were all less than 10% of total CBZ concentrations and, therefore, were unlikely to contribute to the pharmacodynamic effect. Total choice reaction time was significantly more impaired in females (p less than 0.05) but no sex difference occurred with the other tests or CBZ concentrations at any time point. No significant correlations were found between individual total or free CBZ concentrations and corresponding test performances at each time point.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Genetic markers in epilepsy: a survey.

In a study of genetic markets in patients with epilepsy, 30 genetic systems have been tested and the results compared with all previously published studies on this subjects. Only one marker, Ss + ss/SS in the MNSs blood group system showed a statistically highly significant difference (p below 0.001) in the epileptic patients compared with a control group. A previously reported difference in the Pc gene of the red cell acid phosphatase system was not confirmed in the present study. The basis for an association between the S antigen and epilepsy is difficult to understand at present and will need to to be confirmed by studies on other groups of epileptic patients and in the aetiologically different groups before being accepted. This is especially so as the Chalfont patients are the only group so far studied for this blood group system.

Blood Group Antigens↗

Effects of sodium valproate on the serum protein binding of phenytoin, and on liver enzyme activity.

The effect of a single dose of sodium valproate on the serum protein binding of phenytoin was studied in 6 epileptic patients receiving phenytoin maintenance therapy. Phenytoin was significantly displaced by valproic acid, but the free concentration of phenytoin was unchanged because of redistribution to tissues. As a result of this effect, total serum phenytoin concentration was significantly lowered. Induction of metabolism probably does not play a part in this interaction because antipyrine half-lives and urinary D-glucaric acid excretion were not altered by chronic administration of sodium valproate to 8 patients receiving this drug alone.

Antipyrine↗

Involuntary movements caused by phenytoin intoxication in epileptic patients.

The case histories of four patients who developed choreoathetoid movements during intoxication with phenytoin are presented. Drug intoxication was confirmed in each case by measuring the serum phenytoin concentration. Drug interactions were, in part, responsible for the occurrence of intoxication in three of them. Phenytoin intoxication is not always easy to recognize, particularly when nystagmus is minimal or absent, as in these four patients. The estimation of the serum phenytoin concentration is invaluable in this situation.

Adult↗