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A Flood

Publications and source records attributed to A Flood.

11 recordsLinked to original sources
PubMed2001

Functional characterization of coronary vascular adenosine receptors in the mouse.

Coronary responses to adenosine agonists were assessed in perfused mouse and rat hearts. The roles of nitric oxide (NO) and ATP-dependent K(+) channels (K(ATP)) were studied in the mouse. Resting coronary resistance was lower in mouse vs rat, as was minimal resistance (2.2+/-0.1 vs 3.8+/-0.2 mmHg ml(-1) min(-1) g(-1)). Peak hyperaemic flow after 20 - 60 s occlusion was greater in mouse. Adenosine agonists induced coronary dilation in mouse, with pEC(50)s of 9.4+/-0.1 for 2-[p-(2-carboxyethyl)phenethylamino]-5'-N-ethyl carboxamidoadenosine (CGS21680, A(2A)-selective agonist), 9.3+/-0.1 for 5'-N-ethylcarboxamidoadenosine (NECA, A(1)/A(2) agonist), 8.4+/-0.1 for 2-chloroadenosine (A(1)/A(2) agonist), 7.7+/-0.1 for N(6)-(R)-(phenylisopropyl)adenosine (R-PIA, A(1)/A(2B) selective), and 6.8+/-0.2 for adenosine. The potency order (CGS21680=NECA>2-chloroadenosine>R-PIA>adenosine) supports A(2A) adenosine receptor-mediated dilation in mouse coronary vessels. 0.2 - 2 microM of the A(2B)-selective antagonist alloxazine failed to alter CGS21680 or 2-chloroadenosine responses. pEC(50)s in rat were 6.7+/-0.2 for CGS21680, 7.3+/-0.1 for NECA, 7.6+/-0.1 for 2-chloroadenosine, 7.2+/-0.1 for R-PIA, and 6.2+/-0.1 for adenosine (2-chloroadenosine>NECA=R-PIA>CGS21680> adenosine), supporting an A(2B) adenosine receptor response. NO-synthase antagonism with 50 microM N(G)-nitro L-arginine (L-NOARG) increased resistance by approximately 25%, and inhibited responses to CGS21680 (pEC(50)=9.0+/-0.1), 2-chloroadenosine (pEC(50)=7.3+/-0.2) and endothelial-dependent ADP, but not sodium nitroprusside (SNP). K(ATP) channel blockade with 5 microM glibenclamide increased resistance by approximately 80% and inhibited responses to CGS21680 in control (pEC(50)=8.3+/-0.1) and L-NOARG-treated hearts (pEC(50)=7.3+/-0.1), and to 2-chloroadenosine in control (pEC(50)=6.7+/-0.1) and L-NOARG-treated hearts (pEC(50)=5.9+/-0.2). In summary, mouse coronary vessels are more sensitive to adenosine than rat vessels. A(2A) adenosine receptors mediate dilation in mouse coronary vessels vs A(2B) receptors in rat. Responses in the mouse involve a sensitive NO-dependent response and K(ATP)-dependent dilation.

2-Chloroadenosine↗
PubMed2001

Functional properties and responses to ischaemia-reperfusion in Langendorff perfused mouse heart.

Despite minimal model characterisation Langendorff perfused murine hearts are increasingly employed in cardiovascular research, and particularly in studies of myocardial ischaemia and reperfusion. Reported contractility remains poor and ischaemic recoveries variable. We characterised function in C57/BL6 mouse hearts using a ventricular balloon or apicobasal displacement and assessed responses to 10-30 min global ischaemia. We examined the functional effects of pacing, ventricular balloon design, perfusate filtration, [Ca(2+)] and temperature. Contractility was high in isovolumically functioning mouse hearts (measured as the change in pressure with time (+dP/dt), 6000-7000 mmHg s(-1)) and was optimal at a heart rate of approximately 420 beats min(-1), with the vasculature sub-maximally dilated, and the cellular energy state high. Post-ischaemic recovery (after 40 min reperfusion) was related to the ischaemic duration: developed pressure recovered by 82 +/- 5 %, 73 +/- 4 %, 68 +/- 3 %, 57 +/- 2 % and 41 +/- 5 % after 10, 15, 20, 25 and 30 min ischaemia, respectively. Ventricular compliance and elastance were both reduced post-ischaemia. Post-ischaemic recoveries were lower in the apicobasal model (80 +/- 4 %, 58 +/- 7 %, 40 +/- 3 %, 32 +/- 7 % and 25 +/- 5 %) despite greater reflow and lower metabolic rate (pre-ischaemic myocardial O(2) consumption (V(O2,myo)) 127 +/- 15 vs. 198 +/- 17 microl O(2) min(-1) g(-1)), contracture, enzyme and purine efflux. Electrical pacing slowed recovery in both models, small ventricular balloons (unpressurised volumes < 50-60 microl) artificially depressed ventricular function and recovery from ischaemia, and failure to filter the perfusion fluid to < 0.45 microm depressed pre- and post-ischaemic function. With attention to these various experimental factors, the buffer perfused isovolumically contracting mouse heart is shown to be stable and highly energized, and to possess a high level of contractility. The isovolumic model is more reliable in assessing ischaemic responses than the commonly employed apicobasal model.

Animals↗
PubMed1998

PCR-based apolipoprotein E genotype analysis from archival fixed brain.

A technique is described for determining the apolipoprotein E genotype (apo E; alleles epsilon2, epsilon3, or epsilon4) from tissues which have been fixed with 4-10% formaldehyde and archived. The procedure requires efficient extraction and exhaustive purification of DNA from the fixed tissue. Because the fixation process renders the DNA largely crosslinked and/or sheared (therefore unsuitable for traditional analysis), a nested polymerase chain reaction (PCR) is employed (using two apo E gene specific primer pairs) to specifically amplify the polymorphic region of the gene. The genotype was then determined using previously reported HhaI polymorphisms that occur as a direct result of the variant codons responsible for the three alleles. This protocol permitted the successful genotyping of 90% (34 out of 38) of the archived brain samples from Alzheimer's disease (AD) patients. These samples included such extremes as a sample that had been stored for 12 years in formalin. This procedure permits the retrospective analysis of samples that had been processed and stored well before the original characterization of apo E alleles as risk factors in AD. Finally, this approach is readily adapted to the analysis of any gene of interest, whether by restriction fragment length polymorphism or direct amplicon DNA sequencing. It is also a very robust assay for less stringent conditions such as DNA isolated from whole blood or frozen tissue.

Alzheimer Disease↗
PubMed1991

Reliability of questionnaire responses as compared with interview in the elderly: views of the outcome of transurethral resection of the prostate.

Three hundred and eighty-eight men undergoing transurethral resection of the prostate for benign prostatic hypertrophy completed a presurgical questionnaire and three follow-up questionnaires 3, 6 and 12 months after surgery. The questionnaires covered details of prostatic symptoms, general health, and expectations and results of surgery. At each follow-up point 40 randomly selected patients were interviewed by two female research assistants. The response rate to the questionnaires was over 90% at each follow-up point while that for the interviews was lower at around 80%. We examine the reliability of the postal questionnaires in assessing health status by comparing questionnaire and interview responses, with a view to the wider employment of such a method in the follow-up of surgical patients. In general, and as reported elsewhere, responses to questions on easily defined topics are highly comparable between questionnaire and interview. Responses to more subjective questions are moderately reliable, but with a tendency for postal questionnaires to underestimate a patient's health problems. It is difficult to assess the reliability of the questionnaires with regard to questions of an intimate nature since such questions caused embarrassment during interview with consequent incomplete responses.

Adult↗
PubMed1991

Do doctors and patients agree? Views of the outcome of transurethral resection of the prostate.

In an attempt to establish the extent to which patients and doctors agree on the outcome of health care, the pre- and postoperative states of health of 388 men undergoing transurethral resection of the prostate for benign disease were studied. Generally, high levels of concordance (greater than 70%) were obtained. The strongest agreement was for clearly defined events, such as episodes of acute retention (95%); the weakest agreement occurred over the most subjective symptoms, prognostic expectations, and ambiguous terms (around 60%). The level of agreement was not associated with any characteristics of the patient, surgeon, or treatment.

Cystoscopy↗
PubMed1989

Linkage analysis of families with fragile-X mental retardation, using a novel RFLP marker (DXS 304).

A new polymorphic DNA marker U6.2, defining the locus DXS304, was recently isolated and mapped to the Xq27 region of the X chromosome. In the previous communication we describe a linkage study encompassing 16 fragile-X families and using U6.2 and five previously described polymorphic markers at Xq26-q28. One recombination event was observed between DXS304 and the fragile-X locus in 36 informative meioses. Combined with information from other reports, our results suggest the following order of the examined loci on Xq: cen-F9-DXS105-DXS98-FRAXA-DXS304-(DXS52-F8 -DXS15). The locus DXS304 is closely linked to FRAXA, giving a peak lod score of 5.86 at a corresponding recombination fraction of .00. On the basis of the present results, it is apparent that U6.2 is a useful probe for carrier and prenatal diagnosis in fragile-X families.

Chromosome Mapping↗
PubMed1985

Effect of folic acid treatment in the fragile X syndrome.

The effect of folic acid intake on the frequency of fragile X positive cells and some behavioural characteristics were evaluated in 5 boys and 4 adult males with the fragile X syndrome. The expression of fragile X was nullified in 6 and decreased in 3 of the 9 patients. Behavioural and motor ability were considered to have improved in 4 of the 5 boys but not in the 4 adults with fragile X syndrome.

Adolescent↗