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Biomedical subjects

Pierre Dumas

Publications and source records attributed to Pierre Dumas.

16 recordsLinked to original sources

Expresso: automatic incorporation of structural information in multiple sequence alignments using 3D-Coffee.

Expresso is a multiple sequence alignment server that aligns sequences using structural information. The user only needs to provide sequences. The server runs BLAST to identify close homologues of the sequences within the PDB database. These PDB structures are used as templates to guide the alignment of the original sequences using structure-based sequence alignment methods like SAP or Fugue. The final result is a multiple sequence alignment of the original sequences based on the structural information of the templates. An advanced mode makes it possible to either upload private structures or specify which PDB templates should be used to model each sequence. Providing the suitable structural information is available, Expresso delivers sequence alignments with accuracy comparable with structure-based alignments. The server is available on http://www.tcoffee.org/.

Databases, Protein↗

Biological monitoring of exposure to organophosphorus insecticides in a group of horticultural greenhouse workers.

Exposure to selected organophosphorus insecticides (OPs), malathion, diazinon and acephate, was evaluated in a group of horticultural greenhouse workers. This was achieved through measurements of the cumulative urinary excretion time courses of specific and non-specific biomarkers over a 24 h period following the onset of work exposure. For malathion, the absorbed daily doses were estimated from the 24 h cumulative urinary amounts of the specific mono- and di-carboxylic acid metabolites (the sum of MCA and DCA) through the use of a kinetic model. The observed 24 h urinary levels were also compared with a biological reference value (BRV) of 57 nmol kg(-1) of body weight established in a previous work on the basis of a human no-observed-effect level exposure dose. Excretion values were found to be 2.5% or less of the BRV, suggesting a negligible health risk. Both median and 95th percentile concentrations of DCA (n = 57 samples) were, however, slightly higher than the baseline values determined by the Centers for Disease Control and Prevention (CDC) in the US civilian population (MCA was not analyzed by the CDC). The cumulative urinary excretion time course of the methyl phosphoric (MP) derivatives, which are metabolites of malathion but also of several other OPs, was also determined. Though relatively low, the MP levels were from 3 to 31 times higher than would be expected on the basis of the malathion specific MCA and DCA excretions, indicating that MP excretions stem from sources other than malathion exposure. Accordingly, only the time courses of MCA and DCA excretion rate (nmol h(-1)) were compatible with the time of work exposure. Urinary biomarkers of exposure to diazinon and acephate were also measured. Urinary concentrations were essentially below or equal to the analytical limit of detection of 1 microg l(-1) for 2-isopropyl-4-methyl-6-hydroxypyrimidine (n = 54) and of 0.8 microg l(-1) for acephate and methamidophos (n = 59): values within the baseline range of the US civilian population, like the observed phosphoric metabolite concentrations. The workers under study thus appeared to be only slightly more exposed to malathion than the general population. However, their overall exposure to OPs, as measured by non-specific phosphoric metabolites, was similar to that of the general population, whose exposure occurs mainly through the ingestion of contaminated food. These results question the relevance of measuring non-specific phosphoric metabolites when attempting to assess low-dose occupational exposure to a specific OP.

Biomarkers↗

Biological monitoring of exposure to organophosphate pesticides in children living in peri-urban areas of the Province of Quebec, Canada.

OBJECTIVE: This study was undertaken to assess the exposure to organophosphate (OP) pesticides in children from peri-urban areas of the Province of Quebec, Canada, through measurements of semi-specific alkylphosphate (AP) metabolites. METHODS: Eighty-nine children aged between 3 and 7 years were recruited via pamphlets sent to day-care centers. A first morning urine void was collected early in the spring of 2003 prior to summertime, which is the usual period of outdoor pesticide use. During summertime, up to five more first morning voids were repeatedly collected, at 72-h intervals, over a 13-day period. The potential determinants of exposure were assessed by a questionnaire at the time of urine collection. RESULTS: Methylphosphate metabolites were detectable in 98.2% of the 442 samples analyzed while ethylphosphates were detected in 86.7% of the samples. The geometric mean concentration (GM) of the total AP metabolites was 61.7 mug/g creatinine (range: 2.7-1967.3 mug/g creatinine). The difference in urinary AP concentrations between samples collected during spring and summer was non-significant (P=0.08). There was also no significant difference in the mean AP concentrations between summer samples of individuals living in municipalities where outdoor pesticide use is or is not restricted (P=0.25). However, the presence of a pet in the house was associated with an increase in AP concentrations during spraying season (P=0.02). Pesticides were seldom used, as reported by the questionnaire. A significant correlation was also observed (P<0.001) between the urinary AP concentrations in samples provided by siblings at the same time period. CONCLUSIONS: Mean concentrations of AP were generally higher than those reported in other studies. The observed exposure apparently occurred mainly through the dietary ingestion of OP residues. These data raise questions on the levels of OP residues in Quebec food and the possibility that our participants consumed more fruits and vegetables than those in other studies.

Child↗

Adipose organochlorine concentrations and risk of breast cancer among postmenopausal Danish women.

OBJECTIVE: Exposure to environmental organochlorines has been examined as a potential risk factor for human breast cancer with mixed results. Our purpose was to examine associations between organochlorines and the development of breast cancer in a large prospective study using stored adipose tissue. METHODS: We conducted a nested case-control study of 409 postmenopausal women who developed breast cancer and 409 controls selected from the 29,875 women enrolled in the Danish Diet, Cancer, and Health cohort between 1993 and 1997. We measured concentrations of 14 pesticides and 18 polychlorinated biphenyls in adipose tissue, collected upon enrollment, and estimated relative risk (RR) of breast cancer using conditional logistic regression. RESULTS: The results showed no higher risk of breast cancer among women with higher levels of any pesticides or polychlorinated biphenyls; the RR associated with the upper quartile of 1,1-dichloro-2, 2-bis(p-chlorophenyl)ethylene concentration was 0.7 [95% confidence interval (95% CI), 0.5-1.2] contrasting the lower quartile, and for the sum of polychlorinated biphenyls the similar risk was 1.1 (95% CI, 0.7-1.7). We observed a pattern of substantially lower risk of estrogen receptor-negative breast cancer in association with higher levels of most of the pesticides and polychlorinated biphenyls; the RR for the higher quartile of 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene was 0.1 (95% CI, 0.0-0.5) and for the sum of polychlorinated biphenyls it was 0.3 (95% CI, 0.1-0.9). CONCLUSION: The results do not support that higher organochlorine body levels increase the risk of breast cancer in postmenopausal women. The interpretation of the inverse association for estrogen receptor-negative breast cancer is currently unclear.

Adipose Tissue↗

High-dose 7-hexanoyltaxol-eluting stent with polymer sleeves for coronary revascularization: one-year results from the SCORE randomized trial.

OBJECTIVES: The Study to COmpare REstenosis Rate between QueST and QuaDDS-QP2 (SCORE) trial was a multicenter, randomized, open-label trial comparing the safety and performance of 13- and 17-mm QuaDDS stents (n = 126) (Quanam Medical Corp., Santa Clara, California/Boston Scientific Corp., Natick, Massachusetts) versus uncoated control stents (n = 140) in focal, de novo coronary lesions. BACKGROUND: The pioneering drug-delivery QuaDDS stent used four to six acrylate polymer sleeves, each loaded with 800 microg of the paclitaxel derivative 7-hexanoyltaxol. METHODS: Clinical end points were assessed at 1, 6, and 12 months post procedure. Quantitative coronary angiography and intravascular ultrasound were performed post procedure and at six-month follow-up. RESULTS: In the QuaDDS group, early stent thrombosis and myocardial infarction (MI) rates were significantly higher, leading to premature cessation of enrollment. For the QuaDDS group, the stent thrombosis rate increased from 3.2% to 10.3% between 1 and 12 months, associated with increased non-Q-wave MI and death rates. The angiographic restenosis rate at six months was reduced from 32.7% (control) to 7.4% (p < 0.0001). However, the primary end point was not met with six-month target vessel revascularization (TVR) rate as well as the composite major adverse cardiac event rates (cardiac death, MI, and TVR) comparable between groups. CONCLUSIONS: Despite angiographic indications of potential anti-restenotic benefit, increased rates of stent thrombosis, MI, and cardiac death associated with the QuaDDS stent show an unacceptable safety profile.

Aged↗

Analysis of HO-PCBs and PCP in blood plasma from individuals with high PCB exposure living on the Chukotka Peninsula in the Russian Arctic.

A trace analytical method is presented for the analysis of hydroxylated polychlorinated biphenyl metabolites (HO-PCBs) and pentachlorophenol (PCP) in human plasma. The described methodology is a modification of a previously validated method used for PCB and organochlorine pesticide analysis. The modified method enables the combined analysis of phenolic and neutral halogenated compounds. A tandem Florisil column is used for separating the HO-PCBs and PCP from the neutral fraction, instead of the more common chemical partitioning. In the same step the neutral fraction is purified for GC analysis. The extraction of the HO-PCBs and PCP was found to be highly dependent on sufficient acidification of the sample and the polarity of the extracting solvent. Analysis of plasma samples gave recovery rates for (13)C(6)-PCP and (13)C(12)-4-HO-CB 187 of 64 and 72%, respectively. The limit of detection ranged between 2-20 pg g(-1) plasma for the HO-PCBs and 5 pg g(-1) plasma for PCP. No matrix interferences were observed in the chromatograms. In plasma samples (n = 15) from the native Chukchi people in Uelen (Russian Arctic), a population with high PCB exposure, the median ratio of sum HO-PCBs to sum PCBs was as high as 0.4 and the sum HO-PCBs and PCBs were significantly correlated (r(2) > 0.7, p < 0.01). The median sum HO-PCBs (10 congeners) was 5920 pg g(-1) plasma with 4-HO-CB 107 as the dominating congener (median: 1670 pg g(-1) plasma). The median PCP level was measured at 642 pg g(-1) plasma.

Arctic Regions↗

Impact of anal incontinence and chronic constipation on quality of life.

AIM: To determine the impact of symptoms related to chronic constipation and fecal incontinence on quality of life. PATIENTS AND METHODS: This prospective study included 173 consecutive patients who referred addressed to our laboratory for anorectal manometry. Quality of life was evaluated using the GIQLI questionnaire, and severity of symptoms using the Cleveland Clinic scores for constipation and fecal incontinence. A correlation study was performed between the quality of life and symptoms scores. RESULTS: The GIQLI questionnaire was correctly completed by 157 patients (90.7%). The mean GIQLI score was 89 +/- 24, without any significant difference between constipated and incontinent patients. The mean constipation score was 15.7/30 (range: 6-25). The mean fecal incontinence score was 10.5/20 (range: 3-16). Correlation between quality of life and symptom scores was poor. Thus, a significant threshold value for symptom scores corresponding to major alteration of quality of life could not be determined. CONCLUSIONS: Quality of life is profoundly altered both in patients with chronic constipated and incontinence. Symptom scores do not allow satisfactory evaluation of the impact of chronic constipation or fecal incontinence on patients' quality of life. These results confirm the need for systematic exploration of quality of life in these patients, to correctly address the severity of functional diseases, and the influence of therapy.

Chronic Disease↗

Genomic map of cardiovascular phenotypes of hypertension in female Dahl S rats.

Genetic linkage analyses in human populations have traditionally combined male and female progeny for determination of quantitative trait loci (QTL). In contrast, most rodent studies have focused primarily on males. This study represents an extensive female-specific linkage analysis in which 236 neuroendocrine, renal, and cardiovascular traits related to arterial pressure (BP) were determined in 99 female F2 rats derived from a cross of Dahl salt-sensitive SS/JrHsdMcwi (SS) and Brown Norway normotensive BN/SsNHsdMcwi (BN) rats. We identified 126 QTL for 96 traits on 19 of the 20 autosomal chromosomes of the female progeny. Four chromosomes (3, 6, 7, and 11) were identified as especially important in regulation of arterial pressure and renal function, since aggregates of 8-11 QTL mapped together on these chromosomes. BP QTL in this female population differed considerably from those previously found in male, other female, or mixed sex population linkage analysis studies using SS rats. Kidney weight divided by body weight was identified as an intermediate phenotype that mapped to the same region of the genome as resting diastolic blood pressure and was correlated with that same BP phenotype. Seven other phenotypes were considered as "potential intermediate phenotypes, " which mapped to the same region of the genome as a BP QTL but were not correlated with BP. These included renal vascular responses to ANG II and ACh and indices of baroreceptor responsiveness. Secondary traits were also identified that were likely to be consequences of hypertension (correlated with BP but not mapped to a BP QTL). Seven such traits were found, notably heart rate, plasma cholesterol, and renal glomerular injury. The development of a female rat systems biology map of cardiovascular function represents the first attempt to prioritize those regions of the genome important for development of hypertension and end organ damage in female rats.

Animals↗

TA repeat variation, Npr1 expression, and blood pressure: impact of the Ace locus.

The activity of the atrial natriuretic peptide receptor (Npr1) is altered in spontaneously hypertensive rats (SHR) in relation to its mRNA levels, suggesting abnormal transcriptional control in hypertension. A single-stranded conformational polymorphism caused by a repetitive dinucleotide segment of 10 TA in BN-Lx and of 40 TA in SHR was localized at position -943 relative to the transcription start site of the Npr1 gene, downstream of a putative cGMP-regulatory region, and was the only sequence difference noted between the two strains. Transient transfections of -1520 to -920 Npr1 promoter-SV40-luciferase fusion vector showed that the construct from BN-Lx stimulated the SV40 promoter, whereas that from SHR slightly inhibited it. In contrast to the BN-Lx construct, the activity of the SHR fragment was refractory to downregulation by atrial natriuretic peptide. Genotype-phenotype correlation studies in recombinant inbred strains (RIS) derived from BN-Lx and SHR crosses revealed significant correlations of the TA repeat with basal guanylyl cyclase activity and Npr1 mRNA levels. The correlations were heightened by a locus on chromosome 10 containing the Ace gene. The highest basal guanylyl cyclase activity and Npr1 mRNA values were found in RIS with both genes (Npr1/Ace) of BN genotypes, whereas the lowest were recorded in RIS, with the SHR genotypes at both loci. This was inversely correlated with diastolic blood pressure in these strains. In conclusion, the longer TA repeat unit in the promoter of Npr1 of SHR, in tandem with a putative cGMP responsive element, regulates the transcription of the Npr1 gene with consequences on diastolic blood pressure.

3T3 Cells↗

A randomized comparison of direct stenting with conventional stent implantation in selected patients with acute myocardial infarction.

OBJECTIVES: We sought to determine whether direct stenting might prevent the adverse events associated with stent implantation during primary angioplasty and to compare it with conventional stent implantation in patients with acute myocardial infarction (AMI). BACKGROUND: No trial has demonstrated that stents favorably influence mortality rate. Recent studies have even suggested a negative impact of stents on coronary blood flow and clinical outcome. METHODS: Of 409 patients treated by primary angioplasty with stent implantation in our center, 206 (50%) were enrolled in this randomized, single-center trial and allocated to direct stent implantation (n = 102) or stent implantation after balloon pre-dilation (n = 104). The study end points included angiographic results (final corrected Thrombolysis In Myocardial Infarction [TIMI] frame count and a composite end point of slow and no-reflow or distal embolization), an electrocardiogram marker of myocardial reperfusion assessment (ST-segment resolution) and in-hospital clinical outcome (death and recurrent infarction). RESULTS: Direct stent implantation failed in eight patients but succeeded after pre-dilation in all. A non-significant increase in TIMI flow grade 3 was achieved after direct stenting (95.1% vs. 93.3%, p = 0.74) without significant difference in the corrected TIMI frame count (31.5 +/- 17 and 35.2 +/- 20 frames after direct and conventional stent, respectively, p = 0.42). The composite angiographic end point was significantly reduced by direct stent implantation (11.7% vs. 26.9%, p = 0.01). ST-segment resolution was also significantly improved after direct stent (no ST-segment resolution in 20.2% vs. 38.1% after direct and conventional stent, respectively, p = 0.01). Death and/or recurrent infarction occurred in six patients after conventional stent implantation and in two patients after direct stenting (p = 0.28). CONCLUSIONS: In selected patients with AMI, direct stenting can be applied safely and effectively. This strategy may result in a significant reduction of microvascular injury, as suggested by improved ST-segment resolution after reperfusion with major potential clinical consequences.

Aged↗

Stenting of bifurcation lesions using the Bestent: a prospective dual-center study.

Treatment of bifurcation lesions remains a technical challenge. Among 13 stents previously tested in a bench study, the Bestent seemed of particular interest in this indication as it provided good access to the side branch after stent implantation in the main branch associated with a satisfactory coverage of the lesion after kissing balloon inflation. The use of Bestent implanted in the main branch or both branches for treatment of bifurcation lesions involving a side branch > or = 2.2 mm in diameter was prospectively evaluated in a dual-center prospective study with a prospective 6-month clinical follow-up. All angiographic documents were analyzed by an independent corelab (CORISIS). Between 11 September 1997 and 21 February 1998, 96 patients were consecutively included (mean age, 63.7 +/- 11.4 years; 81.3% male; 58.3% with unstable angina and 6.3% acute myocardial infarction). The lesion involved the left anterior descending-diagonal coronary bifurcation in 55% of cases, left circumflex-marginal 23%, posterior descending-postero-lateral 12%, distal left main 6%, and others 4%. The main branch (proximal reference diameter: 3.43 +/- 0.45 mm) was stented in 98% of cases and the side branch (2.72 +/- 0.38 mm) in 38% (both branches in 34% of cases). T-stenting or provisional T-stenting was used in 88% of cases and final kissing balloon inflation was performed in 78% of cases. Procedural success was obtained in 100% of cases in the main branch and 98% in both branches. Major cardiac and cerebral events (MACCE) during hospitalization occurred in 4.2% of cases, non-Q-wave myocardial infarction (MI) in 3.1%, Q-wave MI in 1.0%, repeat PTCA in 2.1%; there were no major access site complication, no emergency coronary artery bypass grafting operation, no death. At 6-month follow-up, total MACCE rate was 14.6% (Q-wave MI, 3.1%; non-Q-wave MI, 3.1%; target vessel revascularization, 9.4%; death, 2.1%). Patients with target vessel revascularization (TVR) had restenosis of both branches in 22.2% of cases, main branch in 22.2%, and side branch in 55.6%. This study shows that using a simple strategy of provisional T-stenting of the side branch in the majority of cases, the Bestent can be used for treating bifurcation lesions with a high rate of success and an acceptable rate of TVR at 6-month follow-up.

Aged↗

Noncoronary transradial angioplasty with coronary equipment: a less invasive technique.

As the safety and feasibility of the transradial approach for percutaneous coronary interventions have already been established by many series, we evaluate the safety and feasibility of this approach in noncoronary interventions such as renal, celiac, mesenteric, and subclavian angioplasty procedures. We present here our preliminary experience of noncoronary interventions via the transradial approach using coronary equipment with 100% technical and clinical success. Nine noncoronary interventions were performed in seven patients (five renal, two celiac, one mesenteric and subclavian angioplasty each). The advantage of this approach is that it limits arterial wall damage as well as potential distal embolization by the use of small guiding catheters and 0.014" guidewires. The only limitation of this approach for noncoronary interventions is the guiding catheter length in tall patients and the unavailability of large coronary balloons for subclavian, celiac, and renal interventions. With the miniaturization of equipment and improvements in technique, this approach will also become an excellent alternative for noncoronary interventions.

Aged↗

Less invasive PTCA of a gastroepiploic artery combining the transradial approach and 5 Fr guiding catheter: a case report.

The gastroepiploic artery has been successfully used as an arterial conduit in selected patients undergoing CABG with acceptable immediate and long-term results. Myocardial ischemia may occur during the follow-up period as a result of spasm, occlusion, or stenosis at the anastomosis site. Because of tortuosity and in order to avoid graft spasm and to obtain good extra backup support, we require low-profile wide-lumen guiding catheters for deep intubation and increased procedural success. In the case presented here, a gastroepiploic graft stenosis was treated by balloon angioplasty performed through a less invasive approach combining transradial access and use of 5 Fr guiding catheter.

Angioplasty, Balloon, Coronary↗

Identification and chromosomal localization of ecogenetic components of electrolyte excretion.

OBJECTIVE: To determine to what extent urinary excretion of blood pressure-modulating electrolytes is genetically determined, and to identify their chromosomal localization. DESIGN AND METHODS: Twenty-six rat recombinant inbred strains (RIS) originating from reciprocal crosses of normotensive Brown Norway (BN.Lx) and spontaneously hypertensive rats (SHR) were used. A pilot experiment on a subset of strains determined that fasting decreases the impact of environmental noise and increases that of heritability. Twenty-four-hour urinary collections were obtained from fasting rats aged 6-12 weeks (3-8 rats per strain). Sodium (Na), potassium (K) and calcium (Ca) excretions were measured, and the Na/K ratio calculated. These phenotypes served as quantitative traits for the search of quantitative trait loci (QTLs) by scanning the RIS genome that was mapped with 475 polymorphic markers. RESULTS: Constant Na intake resulted in a low heritability for Na excretion, reflecting the environmental impact (intake = excretion), whereas fasting revealed a gradient among RIS indicative of the genetic component of the traits. In the fasting state, a locus on chromosome 14 was found to be significantly associated with K excretion (Alb, P = 0.00002, r = -0.69, logarithm of the odds score (LOD) 3.9), whereas another locus on chromosome 10 (D10Cebrp97s5, P = 0.0003, r = -0.69, LOD 3.0) and one on chromosome 6 (D6Cebrp97s14, P = 0.0007, r = -0.65, LOD 1.9) were more significantly associated with Na excretion and the Na/K ratio respectively. The observed correlations were all negative for Na, K and Na/K, indicating a higher excretion of Na and K and a greater Na/K ratio in rats bearing BN.Lx alleles at these loci, i.e. salt retention in fasting SHR. These three loci accounted for 47-55% of variance of their associated trait, suggesting that they are the main genetic determinants for these phenotypes in basal fasting conditions. Rats bearing the Y chromosome of SHR origin had significantly higher K excretion that, in turn, led to a significantly lower Na/K ratio. Finally, a locus on chromosome 7 was linked to Ca excretion, explaining 46% of the trait variance (D7Mit10, LOD score 3.0). CONCLUSION: RIS enabled us to determine QTLs for environmentally modulated traits such as Na, K and Ca excretions. We demonstrated that whereas urinary electrolytes are determined mainly by intake (environment) in a steady state, their excretion in an adaptive state (fasting) is predominantly genetically determined by distinct QTL on autosomes as well as the Y chromosome. Furthermore, the loci responsible for Na and K excretions act independently of the locus governing the relative excretion of Na/K. Thus, the salt-retaining aspects of some hypertensives may be, in large part, determined by genes responsible for renal excretion, the impact of which is predominant over the environment under acute challenge.

Age Factors↗

Triple vessel stenting for triple vessel coronary disease.

BACKGROUND: Randomized clinical trials have established the feasibility of implanting multiple coronary stents and, in selected patients, have measured survival after multiple stenting to be comparable to coronary artery bypass graft surgery (CABG). However, the proportion of candidates for this therapy is unclear. this prospective study was performed to measure the percentage of patients eligible for elective multiple stenting of triple vessel coronary artery disease and to examine their short- and intermediate-term outcomes. METHODS: Between January 1996 and January 1999, percutaneous coronary interventions (PCI) were performed in 6,810 consecutive patients, of whom 115 (1.7%) had triple vessel coronary artery disease treated with > or =3 stents. The mean age of these patients was 62.9 years (range, 35-85 years), 83% were men and 13 patients (11%) were diabetic. The treatment was performed in a single procedure in 80% of patients and 362 vessels were dilated, including the left anterior descending artery in 85%, the right coronary artery in 84%, the left circumflex in 49%, the left diagonal artery in 27%, the posterior descending artery in 8% and the posterior lateral artery in 4% of patients. RESULTS: A total of 483 stents were implanted, representing an average of 4.2 +/- 1.4 stents per patients (range, 3-10 stents). The total length of stents averaged 66.9 +/- 4.9 mm. In-hospital adverse events included 2 deaths (1.7%), 2 emergency CABG (1.7%) and 5 myocardial infarctions (4.3%). The mean hospitalization duration was 2.7 +/- 2.2 days. During a follow-up ranging between 1 and 36 months (mean, 16.7 months), 2 patients died (1.7%), 2 patients underwent CABG (1.7%) and 22 patients (19.1%) underwent further coronary artery dilatations. The 3-year event-free survival was 71.3%. In univariate analysis, patients who underwent additional target vessel revascularization were younger and were more likely to have stented segments > 80 mm in the index procedure. No other clinical, angiographic or procedural characteristic was predictive of adverse events. CONCLUSIONS: In this consecutive series of patients undergoing elective PCI, candidates for stenting of > or =3 arteries were few. Most eligible patients underwent uncomplicated and immediately successful procedures. The long-term outcome was comparable to controlled studies of CABG, except for a higher rate of repeat revascularization procedures due to restenosis.

Age Factors↗

Isotope dilution-mass spectrometry determination of blood cyanide by headspace gas chromatography.

A direct and sensitive method for the determination of blood cyanide by isotope dilution was developed. The blood is placed in a headspace vial, and K13C15N is added as internal standard. Addition of phosphoric acid liberates the cyanide as HCN. The detection is accomplished by mass spectrometry after a fine mass calibration tuning. The detection limit obtained is 0.3 micromol/L. The within- and inter-run coefficients of variation are 4.4% (for a concentration of 2.5 micromol/L) and 3.9% (for a concentration of 4.7 micromol/L), respectively. The observed recovery is 98%. A round-robin exercise was carried out to compare the performance of this method with others currently in use in other clinical laboratories.

Chromatography, Gas↗