Balloon-expandable stent repair of severe coarctation of aorta

Experimental studies have shown that stents implanted at the aorta become incorporated within the aortic wall and can be further expanded in growing animals. This study evaluates the feasibility and immediate results of balloon-expandable stent implantation in 10 patients with severe coarctation of aorta. The ages of the patients ranged from 1 month to 43 years; 1 was an infant, 8 were children (mean age 5.3 +/- 4 years), and 1 was an adult. All had an unfavorable anatomy for balloon angioplasty; 9 had isthmus hypoplasia. Balloon predilation was first performed and its immediate effect evaluated. Then a balloon-expandable stent that was 30 mm long and covered the isthmus and coarctation levels was deployed, and it was further expanded to the preselected final diameter (12 +/- 4 mm). A final hemodynamic and angiographic evaluation was then obtained. Full deployment of an incompletely expanded and distally displaced stent in the infant led to aortic disruption that was controlled by a second stent covering the disrupted zone and the isthmus. After balloon angioplasty alone was done, the mean gradient (43 +/- 12 vs 31 +/- 10 mm Hg) and the percentage stenosis (72% +/- 11% vs 54% +/- 11%) had an insufficient decrease. However, after stent implantation was done, the gradient almost disappeared (mean 2 +/- 3 mm Hg). The angiographic stenosis disappeared in 7 patients and was markedly reduced in 3. The ratio of isthmus/descending aorta changed from 0.65 +/- 0.14 to 1 +/- 0.08 (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of cocaine and its metabolites in human urine by gas chromatography/mass spectrometry after simultaneous use of cocaine and ethanol

Cocaethylene is an active metabolite produced when cocaine is consumed jointly with ethanol. The development of analytical techniques for determining cocaethylene and other cocaine metabolites is highly relevant for pharmacokinetic and toxicology studies of the cocaine and alcohol interaction in humans. The gas chromatography/mass spectrometry (GC/MS) method here reported is based on a single solid-phase extraction together with deuterated internal standards previously added to urine, followed by derivatization with pentafluoropropionic anhydride (hydroxyl and amine functions) and 1,1,1,3,3,3 hexafluor-2-propanol (carboxylic acid function) and injection into a capillary GC system coupled to a mass spectrometric detector in the selected ion monitoring acquisition mode. A sensitivity of 1-2 ng ml-1 for the quantitative analysis of cocaine and its main metabolites (ecgonine methyl ester, benzoylecgonine, cocaethylene and norcocaine) was achieved. In addition, some other minor metabolites were easily extracted and detected.

Comprehensive screening procedure for detection of stimulants, narcotics, adrenergic drugs, and their metabolites in human urine

An analytical procedure for the detection of stimulants, narcotics, beta-blockers, beta-agonists, and many of their metabolites in urine using a solid-phase extraction procedure and gas chromatography-mass spectrometry (GC-MS) is described. These substances have been specifically banned by the Medical Commission of the International Olympic Committee (IOC) in order to prevent their abuse in sports. Urine samples are submitted to an enzymatic hydrolysis (beta-glucuronidase arylsulfatase) and extracted by means of Bond-Elut Certify columns. The residues are then selectively derivatized with N-methyl-N-trimethylsilyl-trifluoroacetamide (MSTFA), which enables the formation of trimethylsilyl derivatives of hydroxyl, acidic, and phenolic groups, and N-methyl-bis-trifluoroacetamide (MBTFA), which enables the formation of trifluoroacetamide derivatives of primary and secondary amines. A GC-MS system working in scan mode is sensitive and specific enough to detect and identify approximately 100 compounds and metabolites in urine for at least 24 h after the administration of doses typically encountered in therapeutics. Detection in selected ion monitoring mode is needed for the determination of beta-agonist agents. The method was successfully used in doping control of urine samples during the 25th Olympic Games, July 1992, in Barcelona, Spain.

Follow-up patency of side branches covered by intracoronary Palmaz-Schatz stent

To assess the risk of late side branch occlusion after Palmaz-Schatz stent deployment, we analyzed the angiographic evolution of 62 patients treated by successful stent implantation who had a total of 85 side branches starting from the stented segment. Side branches were considered minor (n = 39) when the diameter was < 1 mm and intermediate (n = 46) when the vessel had > or = 1 mm diameter. One angiographic follow-up study was available in all patients at 8 +/- 5 months. Eight minor branches presented some degree of stenosis at origin before stent deployment (4 totally occluded). After stent deployment, 32 (82%) of 39 remained unchanged and 3 became occluded. Late progression at origin occurred in 4 of 34 (3 occluded). Before stent deployment, 48% of the intermediate branches had some compromise degree at their starting point (1 totally occluded). Eight of 45 intermediate branches became occluded after stent implantation. Late progression at origin happened in 5 of 32 branches (2 occluded). Some degree of follow-up stenosis regression at the origin was observed in 22 (26%) of 85 arteries. Neither clinical nor angiographic factors could be identified as predictors of late side branch occlusion or stenosis progression at its origin. Later occlusion or progression at origin of a side branch covered by a Palmaz-Schatz stent seems to be an uncommon occurrence (7% and 12% respectively) that cannot be predicted by angiographic or clinical factors. On the contrary, regression at follow-up of a side branch-origin stenosis can also come about.

Influence of the injection technique on the thermal degradation of cocaine and its metabolites in gas chromatography

Thermal degradation of some substances due to high temperature at the injection port and/or the type of injection technique used may limit the usefulness of gas chromatography with conventional detectors or coupled to mass spectrometry. To minimize thermal degradation of cocaine and its metabolites, chromatography was performed using two different insert liners and a cool on-column inlet. When using a packed liner, marked degradation of all compounds was observed. The degradation process was reduced by the use of an open liner and, when the cool on-column inlet was employed, essentially no degradation occurred.

Systemic exposure to dietary heterocyclic amines in man

2-Amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) and 2-amino-I-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) are formed during the cooking of meat and account for a significant proportion of the mutagenic material present in cooked beef. The amines are not directly mutagenic but are converted to active intermediates by P450. Studies in vitro with human liver have shown that N-hydroxylation catalyzed by CYP1A2 is the major pathway of oxidation of MeQx and PhIP and is solely responsible for the generation of mutagenic species. In the studies reported in this paper it is demonstrated that both MelIQx and PhIP are well absorbed and extensively metabolized following ingestion of amine-containing beef by humans. Experiments with furafylline, a potent and selective inhibitor of human CYP1A2, reveal that more than 90% of MeIQx and 70% of PhIP are N-hydroxylated in vivo, probably presystemically in the liver.

Simultaneous detection of methylphenidate and its main metabolite, ritalinic acid, in doping control

Two analytical methods for the simultaneous detection in urine of methylphenidate and its main metabolite, ritalinic acid, are described. Both procedures are based on solid-phase extraction of urine samples on Bond Elut Certify columns, and capillary gas chromatographic-mass spectrometric detection of O-trimethylsilyl, N-trifluoroacetyl derivatives. The former method is used as a general screening procedure for the detection of basic polar nitrogen-containing compounds in urine such as stimulants, narcotic and adrenergic drugs. The latter procedure is proposed as a specific method to confirm methylphenidate ingestion. The two methods are sensitive enough to detect methylphenidate and ritalinic acid in urine at least for 24 h after administration of a therapeutic dose (20 mg oral dose) of methylphenidate.

[An analysis of the factors and phenomena associated with the formation of a spontaneous echo contrast in the left atrium]

INTRODUCTION AND AIMS

To determine the factors related to the formation of spontaneous echo contrast in left atrium.

PATIENTS AND METHODS

We have analyzed our series of 1,066 patients undergoing transesophageal echocardiography until December 1991. It was found in left atrium in 387 patients (36%) and was associated with another pathology in 99%. We defined spontaneous echo contrast as mild in 64% and severe in 36%.

RESULTS

The prevalence of spontaneous echo contrast was greater in patients with atrial fibrillation (p < 0.001), mitral stenosis (p < 0.001), double mitral lesion (p < 0.001), prosthesis (p < 0.001), embolism (p < 0.05) and a dilated left atrium (left atrial dimension greater than 60 ml) (p < 0.01). The presence of mitral regurgitation made it less frequent (p < 0.05). Thrombi were visualized in 104 patients and they were more frequent in the presence of spontaneous echo contrast. Severe spontaneous echo contrast was significantly more frequent in patients with atrial fibrillation (p < 0.001), mitral stenosis (p < 0.05) and thrombi (p < 0.001).

CONCLUSIONS

Spontaneous echo contrast in left atrium is a common finding in transesophageal studies and it is associated with another pathology in 99%. It is more frequent in patients with atrial fibrillation, mitral stenosis, embolism or prosthesis. Left atrial enlargement is one of the more important factors. It is less frequent in patients with mitral regurgitation. Thrombi are less frequent in patients without spontaneous echo contrast. Severe spontaneous echo contrast is significantly associated with mitral stenosis, atrial fibrillation and left atrial thrombi.

CYP1A2-catalyzed conversion of dietary heterocyclic amines to their proximate carcinogens is their major route of metabolism in humans

The contribution of CYP1A2 to the metabolism of the dietary heterocyclic amines, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) in vivo in humans, has been determined with furafylline, a highly selective inhibitor of this enzyme. The inhibitory potential of furafylline in vivo was first assessed by determining its effect on clearance of phenacetin to paracetamol by the model CYP1A2-dependent O-deethylation pathway. Furafylline inhibited this reaction by > 99% in all subjects, thus demonstrating its applicability to determining the contribution of CYP1A2 to a given reaction in vivo. A group of 6 healthy male volunteers received either placebo or 125 mg furafylline, in a double-blind balanced crossover design, 2 h prior to consuming a test meal of fried beef containing a known amount of amines. The excretion of PhIP and MeIQx in urine was determined during the subsequent 28 h, using gas chromatography-mass spectrometry. Following furafylline, the excretion of unchanged MeIQx increased 14.3-fold, while that of PhIP increased 4.1-fold (P < 0.01, paired t test). Elimination of both amines was first order and very rapid, with half-lives of < 5 h. The elimination rate constants did not change following furafylline, suggesting that total clearance is limited by hepatic blood flow. Because the elimination of the amines was first order, it was possible to calculate the contribution of CYP1A2 to the clearance of the amines. CYP1A2-catalyzed metabolism accounts for 91% of the elimination of ingested MeIQx and 70% of ingested PhIP, most likely via N-hydroxylation.

[Insulin-like growth factor I as a marker of nutritional status in patients on enteral nutrition]

In order to appraise type 1 insulin growth factor (IGF-1) as nutritional state marker in comparison with other known markers, seric IGF-1 (RIA), albumin, prealbumin, transferrin and retinol-bound protein were determined weekly in 15 patients with oropharyngeal neoplasm and 7 in the burns unit, all being administered enteral nutrition. At the beginning of the study, IGF-1 seric levels were significantly lower in the burns group compared with the neoplasm group (82.28 +/- 23.36 vs 137.58 +/- 66.2 ng/ml, p < 0.01). IGF-1 values in the first group were initially significantly lower in comparison with those for the same group at the end of the study (82.28-23.36 vs 177.11 +/- 53.87 ng/ml, p < 0.01 for paired data). No significant change was demonstrated in IGF-1 seric levels in the neoplasm group. IGF-1 seric levels showed a significant multiple correlation with albumin, prealbumin, transferrin and retinol-bound protein in both the group with burns (r = 0.696, p < 0.001) and that with neoplasms (r = 0.615, p < 0.001). The nitrogen balance revealed a univariant and significant linear correlation with IGF-1 (r = 0.373, p < 0.05) and with prealbumin (r = 0.377, p < 0.05). According to the data obtained, seric IGF-1 has a significant correlation with other well-known nutritional markers. In the burns group, the hypercatabolism was accompanied by a significant increase in seric IGF-1 levels.

A randomized study comparing deflazacort and prednisone in heart transplant patients

Prednisone is widely used by most heart transplantation units despite its frequent side effects. Deflazacort, an oral synthetic steroid with fewer side effects, has been successfully used in patients after heart transplantation, but a prospective study comparing deflazacort and prednisone in transplant patients is lacking. We have carried out, in the last year, a prospective trial of deflazacort versus prednisone involving 35 consecutive heart transplant patients. Two of these patients died perioperatively (surgical mortality, 5.7%), and another two were excluded from the protocol because of diabetes mellitus in one patient and active infection before transplantation in the other patient. Thus 31 patients were enrolled in the 3-month study. All of them were treated with antithymocyte globulin, 10 mg/kg/day for 3 days after transplantation, azathioprine, and cyclosporine; patients were randomly assigned groups: 15 patients to receive deflazacort therapy, 1.5 mg/kg/day, and 16 patients to receive prednisone therapy, 1 mg/kg/day, starting the first day after transplantation. Steroids were rapidly tapered, reaching the maintenance dose at 2 to 3 weeks after transplantation (prednisone, 0.15 mg/kg/day; deflazacort, 0.25 mg/kg/day). Both groups were similar in terms of age, gender, ABO identity, serum cyclosporine levels, azathioprine dosage, and pretransplantation serum glucose and lipids levels. Seven endomyocardial biopsies were performed on each patient, at 1, 2, 3, 5, 7, 10, and 13 weeks after transplantation. Incidence of acute rejection was similar between prednisone and deflazacort groups; 33% of patients receiving prednisone therapy and 42% of patients receiving deflazacort therapy had one episode of 3A or higher rejection (not significant).(ABSTRACT TRUNCATED AT 250 WORDS)

Alcohol and cocaine interactions in humans

The effects of 100 mg of intranasal cocaine (COC) in acute alcohol intoxication (1 g/kg) was assessed in nine experienced and non-dependent healthy volunteers in a double-blind, controlled, randomized, cross-over clinical trial. Alcohol alone impaired psychomotor performance, whereas COC alone produced subjective effects related to euphoria and well-being, improved the reaction time and increased heart rate and blood pressure. The combination of COC and alcohol induced a nonsignificant decrease in the subjective feelings of drunkeness, an increase in COC-induced euphoria, a significant improvement in alcohol-related changes in psychomotor performance and a marked increase in heart rate. Subjects experienced subjective and performance effects that could be self-interpreted as more pleasant compared to the effects of alcohol alone. When alcohol was given simultaneously, COC plasma levels were higher (possibly as a result of an inhibition of hepatic metabolism of COC produced by alcohol), norcocaine plasma levels almost doubled and cocaethylene was detected in plasma, so that its basic pharmacokinetic profile could be described. The simultaneous use of both drugs produced changes in heart rate and blood pressure that could increase the risk of cardiovascular toxicity associated with the use of COC.

International cooperation in analytical chemistry: experience of antidoping control at the XI Pan American Games

We describe the experience of the international cooperation carried out for antidoping control at the XI Pan American Games. A temporary accreditation was granted by the International Olympic Committee to the accredited laboratory of Barcelona (Spain) to set up a Doping Control Laboratory in Havana. Two other laboratories from Mexico and Cuba contributed personnel, materials, and instrumentation. The main issues associated with the preparation and organization of the project are described. During 16 days, 741 urine samples were tested for stimulants, narcotics, anabolic steroids, beta-blockers, diuretics, cannabinoids, local anesthetics, and human chorionic gonadotropin by gas-liquid chromatography, gas chromatography/mass spectrometry, high-performance liquid chromatography, and immunoassay techniques. Analytical methodologies, quality-control strategies, and the main results are reported.

International cooperation in analytical chemistry: experience of antidoping control at the XI Pan American Games

We describe the experience of the international cooperation carried out for antidoping control at the XI Pan American Games. A temporary accreditation was granted by the International Olympic Committee to the accredited laboratory of Barcelona (Spain) to set up a Doping Control Laboratory in Havana. Two other laboratories from Mexico and Cuba contributed personnel, materials, and instrumentation. The main issues associated with the preparation and organization of the project are described. During 16 days, 741 urine samples were tested for stimulants, narcotics, anabolic steroids, beta-blockers, diuretics, cannabinoids, local anesthetics, and human chorionic gonadotropin by gas-liquid chromatography, gas chromatography/mass spectrometry, high-performance liquid chromatography, and immunoassay techniques. Analytical methodologies, quality-control strategies, and the main results are reported.

[Listeria monocytogenes endocarditis in a patient with mitral prosthesis, left auricular thrombus and adenocarcinoma of the colon]

A case of Listeria monocytogenes endocarditis in a patient with mitral prosthetic valve, left atrial thrombus and colonic adenocarcinoma is reported. Vegetations were not demonstrated by transesophageal echocardiography and the clinical course was benign and without complications. Cure was achieved with antibiotic therapy, and surgery was not required. These features suggest that atrial thrombus could be the source of infection.

The pathogenesis of nodular regenerative hyperplasia of the liver associated with rheumatoid vasculitis

Nodular regenerative hyperplasia (NRH) is an uncommon liver disease that typically develops in the setting of a chronic illness such as Felty's syndrome. Although the pathogenesis of NRH has not been defined, vasculitis has been postulated to play an important pathogenetic role in some cases of NRH, even though the association of NRH and vasculitis has been reported rarely. We describe two unusual cases of NRH in patients with Felty's syndrome complicated by rheumatoid vasculitis. Morphometric analysis demonstrated evidence of injury to the hepatic vasculature in the form of loss of small intrahepatic arteries and portal spaces, findings that support the hypothesis that hepatic arteritis plays a role in the development of NRH in cases associated with systemic vasculitis.

[Bradyarrhythmias secondary to the use of ophthalmic timolol. A report of 3 cases]

Three cases of symptomatic bradycardia due to topical ocular timolol administration are reported. Two patients had syncope related to atrioventricular block, and the other one complained of dizziness due to sinus bradycardia. Heart disease was not present in any case, although a right bundle branch block was observed in one patients. A normal sinus rhythm resumed in all patients after discontinuation of timolol.

[Acute pericarditis as initial clinical manifestation of hypereosinophilia syndrome]

The case of a patient in whom acute pericarditis was the initial manifestation of an idiopathic hypereosinophilia is reported. Endomyocardial abnormalities were not found by echocardiography. Response to prednisone therapy was good; symptoms, pericardial effusion and eosinophilia early disappeared after therapy. Some clinical aspects of this uncommon disease are discussed.

Immediate and follow-up results of transluminal balloon dilation for discrete subaortic stenosis

This study presents the findings in 33 patients with discrete subaortic stenosis who were treated by percutaneous balloon dilation and were followed up for 2 months to 6.2 years (mean 34 +/- 21 months). The mean age was 13 +/- 11 years; 10 (30%) were female and 23 (70%) male. Associated malformations were observed in nine patients (27%). All patients underwent noninvasive studies and cardiac catheterization. The mean value to membrane distance was 4.5 +/- 2 mm/m2. After balloon dilation, the pressure gradient from the left ventricle to the aorta decreased from 68 +/- 30 to 20 +/- 13 mm Hg (p less than 0.00001); there were no significant changes in the degree of aortic regurgitation. A fluttering and widely mobile remaining membrane was clearly visualized after dilation. Better immediate results were obtained in patients with a smaller baseline gradient, a larger aortic anulus and a longer valve to membrane distance. Serial follow-up echographic studies were available in 30 patients, and 18 hemodynamic reevaluations were performed in 13 patients. However, seven patients who demonstrated restenosis underwent redilation at a mean of 29 +/- 17 months after the first dilation. Redilation in six of the seven patients obtained benefits similar to those observed at the first dilation. Only one patient with unsuccessful redilation required surgery. The mean value of the last explored residual gradient (on hemodynamic or Doppler study) in the remaining 32 patients was 21 +/- 10 mm Hg. No significant changes were observed in the angiographic evolution of aortic regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Balloon valvuloplasty for mild mitral stenosis

Of a total number of 288 patients with mitral stenosis treated by percutaneous balloon valvuloplasty, 21 patients had a basal mitral area equal to or greater than 1.5 cm2, as measured hemodynamically. The immediate hemodynamic results of this particular group of patients with mild mitral stenosis are described, as well as the clinical and echo doppler findings at follow-up (22 +/- 12 mo). Patients with mild mitral stenosis (group I) had more pliable valves (p less than 0.01), as assessed by echo, and higher incidence of sinus rhythm (p less than 0.02) than that observed in the remaining 267 patients (group II). After valvuloplasty the valve area increased in group I from 1.7 +/- 0.2 to 3.1 +/- 0.7 cm2 (p less than 0.0001). This mean final area was significantly different (p less than 0.0001) than that observed in group II (1.98 +/- 0.6 cm2). No patients with mild mitral stenosis developed progression of mitral regurgitation, and none had any other major complications. Most of them reached a grade I final functional status. At echo doppler follow-up studies we did not observe significant changes in the mean mitral gradient as compared with the immediate hemodynamic results. These findings suggest that early mitral balloon valvuloplasty could be an alternative in trying to favorably influence the natural course of the rheumatic mitral disease in selected patients.

Effect of subject expectancy on the THC intoxication and disposition from smoked hashish cigarettes

Subject expectancy on cannabis effects was assessed in a balanced-placebo study in experienced consumers who smoked cigarettes containing hashish (200 mg hashish with 11.5% THC per 1 g tobacco cigarette) (n = 24) or placebo (n = 24). Although statistically significant differences were not found between subjects who received the drug with positive or negative expectancy, a tendency toward more marked subjective effects was shown in subjects who expected and received the drug. This trend was supported by the significant difference observed in the mean AUC0-25 of the heart rate between subjects who smoked hashish with positive or negative expectancies. In subjects who received hashish, the sum AUC0-205 of THC and COOH-THC of those who expected the drug was greater than in those who did not expect it (p less than 0.05). The ratio THC/COOH-THC AUC0-205 was lower in those with positive expectancy than in those with negative expectancy (p less than 0.02). An increased metabolism of THC was shown in subjects with positive expectancy. Positive expectancy induced powerful subjective effects in the absence of active THC. Expectancy appeared to influence smoking behavior, as seen in higher plasma levels of cannabinoids for the group who received the drug.

[Comparative multicentric study of omeprazole versus ranitidine in the treatment of duodenal ulcer]

A total of 158 patients, aged 19-78 years and with endoscopically verified duodenal ulcer of at least 5 mm in maximum diameter were recruited. 79 patients were randomised to treatment with omeprazole, a proton-pump inhibitor of the parietal cell, and 79 patients were treated with ranitidine. This double blind study is the first clinical trial with omeprazole in Spain. Using "intention to treat" analysis there was no difference in healing rates at 2 weeks between the omeprazole group (70%) and the ranitidine group (59%) with p = 0.13. At four weeks, however, omeprazole healed significantly more patients (92%) than ranitidine (76%) with p = 0.005. Using per protocol analysis a similar result was obtained with no significant difference between omeprazole (71%) and ranitidine (63%) at two weeks (p = 0.3) but significantly greater healing on omeprazole at 4 weeks (97%) compared with ranitidine (83%) with p = 0.008. The influence of additional prognostic factors was assessed using a multivariate analysis. At two and four weeks, there was a significant effect of ulcer size on healing rate. At four weeks there was also a significant effect of treatment. Symptom relief was rapid in both treatments but the omeprazole group had significantly fewer days of pain and better patient's overall evaluation than ranitidine group. No serious adverse events were reported. In conclusion omeprazole healed significantly more duodenal ulcers than ranitidine and symptom relief was more rapid during omeprazole therapy.

[Coronary permeability and left ventricular function following thrombolytic therapy]

We study 40 patients, 55 +/- 7 years old with acute myocardial infarction treated early by thrombolytic therapy (20 STK and 20 rt-PA). All patients were angiographically studied in the following conditions: 1) baseline, before initiating therapy. 2) Three hours after treatment. 3) Twenty four hours later. 4) Before discharge. The infarct related artery was patent 24 hours after treatment in 31 patients (78%); five of them were patent before treatment, and we observed an early reperfusion in 20 patients (57%) and late reperfusion in 6 patients (17%). The number of patients with angiographic evidence of intraluminal thrombus decreased progressively through conditions while the grade TIMI of coronary perfusion increased in the absence of reocclusion. Final regional wall motion of infarct related myocardial zones and their degree of recovery were significantly higher in recanalized patients, as compared with non-reperfused patients. Similarly, left ventricular functional recovery was higher in patients with antegrade of collateral flow to the infarct area, as compared with totally occluded patients.

Approach to the analysis of diuretics and masking agents by high-performance liquid chromatography-mass spectrometry in doping control

The application of thermospray and plasmaspray high-performance liquid chromatography-mass spectrometry to the analysis of diuretics and probenecid has been investigated. The latter method gave better ionization efficiency than the former, and its response was optimized by altering the solvent composition: best results were obtained with water-methanol-acetonitrile-trifluoroacetic acid. Using different proportions of these solvents, three isocratic systems were developed to separate the compounds under study. The principal characteristic of plasmaspray positive-ion mass spectra was a protonated molecular ion and very little fragmentation was evident. In the negative ionization mode, the plasmaspray method gave mass spectra showing more fragmentation, which resulted in additional structural information. The ability of trifluoroacetic acid to form negative cluster ions precluded its use as a mobile phase component. The minimum detectable amounts determined by the analysis in the positive-ion mode was compound-dependent, but generally ca. 10-150 ng. In many cases the compounds could be detected in urine extracts.

[Valvulopathies (XIV). The role of percutaneous valvuloplasty in congenital valvular diseases]

The present article describes the cooperative experience Córdoba-Las Palmas since 1983 in 123 patients with congenital right or left ventricular outflow obstructions who were treated by percutaneous balloon dilatation. Seventy of them had pulmonary stenosis (63 valvular and seven supravalvular types); two had pulmonary atresia, 25 valvular aortic stenosis and 27 discrete subaortic stenosis. In patients with valvular pulmonic stenosis the gradient and the right ventricular pressure decreased significantly. No significant changes were observed in the degree of pulmonary regurgitation. One neonate died. No other major complications occurred. After a mean follow up of 3 +/- 2 years, we did not observe significant changes in the degree of pressure relief. The mean residual gradient is 26 +/- 19 mmHg. In our 21 patients out of the neonatal period with valvular aortic stenosis the gradient and the left ventricular pressure dropped significantly. Progression of aortic regurgitation in more than I grade was observed in 4 patients (19%), although only one (5%) progressed to grade III. There were no major complications in this group. After a mean follow up period of 24 +/- 17 months they persist with the obtained pressure relief and same degree of valvular competence. All 4 neonates with critical aortic stenosis had unsuccessful dilations and they died, wether after ulterior surgery or without it. In 27 patients with discrete subaortic stenosis the gradient and the left ventricular pressure decreased markedly, without significant changes in valve competence. There were no related major complications. After dilation, a broken and mobile membrane was frequently seen. At follow up (24 +/- 18 months), 6 patients (22%) had restenosis; five of them were successfully redilated. The remaining 21 patients persist with a reduced residual gradient (24 +/- 7 mmHg) and without significant changes in valve competence.

Selective in-vitro inhibition of hepatic oxidative metabolism by quinolones: 7-ethoxyresorufin and caffeine as model substrates

The in-vitro inhibition of several metabolic pathways has been studied in 3-methylcholanthrene-treated rats. The specificity of the 7-ethoxyresorufin O-de-ethylase reaction has been determined in the presence and absence of ciprofloxacin, enoxacin, norfloxacin, ofloxacin, nalidixic acid, oxolinic acid and pipemidic acid. For the caffeine N3-demethylation reaction, enoxacin and pipemidic acid were used. Enoxacin (IC50 = 105 microM, Ki = 65 microM) and pipemidic acid (IC50 = 115 microM, Ki = 160 microM) significantly inhibited 7-ethoxyresorufin O-de-ethylase reaction and caffeine N3-demethylation (IC50 = 60 microM for enoxacin and IC50 = 185 microM for pipemidic acid) by a competitive mechanism. Other quinolones had lower or no (ofloxacin) inhibitory capacity. The order of inhibitory activity observed is in agreement with results obtained previously from in-vivo studies in man. No activity was detected towards ethylmorphine N-demethylation.

Species variation in the response of the cytochrome P-450-dependent monooxygenase system to inducers and inhibitors

1. In the safety evaluation of drugs and other chemicals it is important to evaluate their possible inducing and inhibitory effects on the enzymes of drug metabolism. 2. While many similarities exist between species in their response to inducers and inhibitors, there are also important differences. Possible mechanisms of such variation are considered, with particular reference to the cytochrome P-450 system. 3. Differences in inhibition may be due to differences in inhibitory site of the enzyme involved, which is not always the active site of the enzyme, in competing pathways or in the pharmacokinetics of the inhibitor. 4. Differences in induction could be due to differences in the nature of the induction mechanism, in the isoenzyme induced, in tissue- or age-dependent regulation, in competing pathways for the substrate or its products, or in the pharmacokinetics of the inducing agent. 5. Examples of each of these possible differences are considered, often from our own work on the P450 IA subfamily, and results in animals are compared with those in humans, where possible. 6. At present, the differences between species in their response to inducers and inhibitors make extrapolation to humans from the results of animal studies difficult, so that ultimately such effects should be studied in the species of interest, humans.

[Role of percutaneous valvuloplasty in rheumatic mitral valve stenosis. Córdoba-Las Palmas cooperative study]

This article describes our findings on a prospective and cooperative study (Córdoba-Las Palmas) in 203 patients with mitral stenosis who underwent balloon valvuloplasty using a retrograde transarterial technique. We analyzed the immediate and mid-term results, and studied the factors determining an optimal result and those related to the new appearance or worsening of mitral incompetence after the procedure. On the other hand, we analyzed the results of mitral valvuloplasty in patients with previous mitral surgery, mild mitral stenosis and patients dilated while having an acute pulmonary edema. We observed a marked decrease in mean mitral gradient (17 +/- 7 to 6 +/- 3 mmHg; p less than 0.001) as well as a significant increase in mitral valve area (1.02 +/- 0.4 to 2.04 +/- 0.7 cm2; p less than 0.001). Echo-Doppler follow-up did not show significant changes in the residual mitral valve gradient. Multivariate analysis selected, as independent predictors of an optimal result, the presence of a pliable valve and the absence of basal mitral regurgitation. On the other hand, the presence of a lower ejection fraction, an older age and a higher baseline left ventricular endiastolic volume were independent factors determining progression of mitral regurgitation. In patients with previous mitral surgery, the clinical, echo and hemodynamic profiles, as well as the immediate results, were similar to those observed in patients with unoperated mitral stenosis. In the subgroup of mild mitral stenosis, we observed and optimal result in all cases, without major complications. Mitral valvuloplasty was dramatically effective in 8 patients treated during acute pulmonary edema.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacokinetic determination of relative potency of quinolone inhibition of caffeine disposition

Quinolone is reported to interact with caffeine, often resulting in an increase both in the plasma half-life and AUC, a decrease in total plasma clearance, and little change in the absorption rate constant and maximum plasma level. These complex changes in the pharmacokinetics of caffeine were analyzed experimentally and from published reports in order to determine the nature of the interaction, which is thought to be due to inhibition of caffeine metabolism by quinolones. A simple pharmacokinetic model for the caffeine-quinolone interaction was developed, which provides a unified method for evaluation and comparison of the effect of quinolones on the disposition of caffeine. The model is applicable to other methylxanthines, such as theophylline. The relative potency of the interactions of quinolones with caffeine in humans has been established as enoxacin (100), pipemidic acid (29), ciprofloxacin (11), norfloxacin (9) and ofloxacin (0).

Factors influencing progression of mitral regurgitation after transarterial balloon valvuloplasty for mitral stenosis

This study analyzes the clinical, echocardiographic and hemodynamic factors affecting progression of mitral regurgitation (MR) after transarterial balloon valvuloplasty in 200 consecutive patients with rheumatic mitral stenosis. After valvuloplasty, the mitral valve area increased in all patients, from 1.03 +/- 0.36 to 2.06 +/- 0.71 cm2 (p less than 0.0001). With regard to the basal stage, the mitral valve was competent in 139 patients and there was mild MR in 61 (grade I in 53, and grade II in 8). Three patients had progression of MR induced by a technical deficiency and they were excluded from analysis. Patients were classified into 2 groups on the basis of the degree of MR before and after valvuloplasty: group A--no progression of MR (n = 167; 85%) when the degree of MR did not change, disappeared after valvuloplasty, or increased from grade 0 to I; group B--progression of MR (n = 30; 15%) when the degree of MR increased to greater than or equal to grade II. Progression of MR was observed more frequently in older patients with presence of chronic atrial fibrillation, larger left atrial size and left ventricular volumes, baseline MR, more severe stenosis and a lower ejection fraction. Multivariate analysis selected age, left ventricular volumes and ejection fraction as independent predictors of progression of MR. All these factors suggest that progression of MR after balloon valvuloplasty could be related to a more advanced degree of disease.

Furafylline is a potent and selective inhibitor of cytochrome P450IA2 in man

1. Furafylline (1,8-dimethyl-3-(2'-furfuryl)methylxanthine) is a methylxanthine derivative that was introduced as a long-acting replacement for theophylline in the treatment of asthma. Administration of furafylline was associated with an elevation in plasma levels of caffeine, due to inhibition of caffeine oxidation, a reaction catalysed by one or more hydrocarbon-inducible isoenzymes of P450. We have now investigated the selectivity of inhibition of human monooxygenase activities by furafylline. 2. Furafylline was a potent, non-competitive inhibitor of high affinity phenacetin O-deethylase activity of microsomal fractions of human liver, a reaction catalysed by P450IA2, with an IC50 value of 0.07 microM. 3. Furafylline had either very little or no effect on human monooxygenase activities catalysed by other isoenzymes of P450, including P450IID1, P450IIC, P450IIA. Of particular interest, furafylline did not inhibit P450IA1, assessed from aryl hydrocarbon hydroxylase activity of placental samples from women who smoked cigarettes. 4. It is concluded that furafylline is a highly selective inhibitor of P450IA2 in man. 5. Furafylline was a potent inhibitor of the N3-demethylation of caffeine and of a component of the N1- and N7-demethylation. This confirms earlier suggestions that caffeine is a selective substrate of a hydrocarbon-inducible isoenzyme of P450 in man, and identifies this as P450IA2. Thus, caffeine N3-demethylation should provide a good measure of the activity of P450IA in vivo in man. 6. Although furafylline selectively inhibited P450IA2, relative to P450IA1, in the rat, this was at 1000-times the concentration required to inhibit the human isoenzyme, suggesting a major difference in the active site geometry between the human and the rat orthologues of P50IA2.

Assay of caffeine metabolism in vitro by human liver microsomes using radio-high-performance liquid chromatography

The low turnover of caffeine in vitro by human liver microsomes makes the study of the metabolic pathways of this compound difficult. Analytical methods with high sensitivity and specificity are needed for the detection of its metabolic products. A method based on the on-line radiometric determination of [8C-3H]caffeine and its principal metabolite (paraxanthine) in man has been developed using reversed-phase high-performance liquid chromatography. The method has been successfully employed in preliminary studies of the kinetics of this reaction.

Determination of morphine and codeine in urine by gas chromatography-mass spectrometry

GC-MS is one of the recommended analytical techniques for the identification and confirmation of opiates in urine. A method for the qualitative detection and quantitation of codeine and morphine in urine samples by this technique has been developed. This method is also suitable for the detection of their main metabolites in urine: norcodeine and normorphine. It also allows the identification of 6-monoacetylmorphine in urine, which can be used as a confirmatory marker of heroine abuse. The derivatized compounds are separated by capillary gas chromatography (GC) and identified by mass spectrometry (MS) in the selective ion monitoring acquisition mode (SIM). The recoveries from urine at concentrations of 1000 ng ml-1 are 72% for codeine and 80% for morphine. The method is linear in the range studied (0-1000 ng ml-1) for codeine and morphine.

Simultaneous detection in urine of cocaine and its main metabolites

The simultaneous detection in urine of cocaine (CO), and the main biotransformation products, benzoylecgonine (BE) and ecgonine methyl ester (EME), is difficult due to their different physicochemical properties. The method presented involves a bonded silica solid-phase extraction procedure that allows mixed ionic and apolar interactions with the analyte. After extraction the compounds are derivatized sequentially with ethyliodide to obtain the BE ethyl ester derivative, and with N-methyl-N-trimethylsilyl trifluoroacetamide (MSTFA) to obtain the O-TMS derivatives. The derivatized compounds are then analysed by a capillary (methylphenylsilicone) gas chromatographic system equipped with a specific nitrogen-phosphorus detector. The method is suitable for the confirmation and quantitation of CO and its main metabolites in urine. BE levels in urine samples (n = 20) measured by the described method and by an immunological technique were in close agreement (r = 0.999).

Efficacy of ethanolamine and polidocanol in the eradication of esophageal varices. A prospective randomized trial

A prospective randomized trial has been undertaken to compare the efficacy of two sclerosing agents, Ethanolamine oleate (Et) and Polidocanol (Pl), in the eradication of esophageal varices (EV). Fifty consecutive cirrhotic patients, 22 in the Et and 28 in the Pl group, were included. Clinical data were comparable in both groups. Eradication of the EV was achieved in 81% (18/22) in the Et group and 64.1% (18/28) in the Pl group (p = NS). There was a significant difference in the rate of rebleeding (4 episodes in 3 patients in the Et group and 18 episodes in 13 patients in the Pl group, p less than 0.05). No differences were noted in the number of other complications or mortality. Both sclerosants have proved useful in the eradication of EV, but Et was superior to Pl in the preventation of recurrent bleeding in the course of repeated endoscopic injection sclerotherapy (EIS).

Proficiency testing on drugs of abuse: one year's experience in Spain

The need for external quality control for drugs-of-abuse urinalysis has long been recognized. Based on experiences in other countries, a proficiency testing program has been introduced recently in Spain. Sterile urine samples containing different concentrations of drugs and metabolites are analyzed by participating laboratories four times a year. Comprehensive educational reports reviewed by an advisory committee are released after each batch analysis. The first year's results verify (a) a beneficial influence of the program in regard to reducing errors when adequate techniques are used, (b) the need for using confirmatory techniques, and (c) the importance of experience and laboratory resources for optimizing results. The educational aspects of the program for the second year are stressing especially the in situ training of analysts and the supply of solutions of drugs and metabolites to be used as reference standards.

Proficiency testing on drugs of abuse: one year's experience in Spain

The need for external quality control for drugs-of-abuse urinalysis has long been recognized. Based on experiences in other countries, a proficiency testing program has been introduced recently in Spain. Sterile urine samples containing different concentrations of drugs and metabolites are analyzed by participating laboratories four times a year. Comprehensive educational reports reviewed by an advisory committee are released after each batch analysis. The first year's results verify (a) a beneficial influence of the program in regard to reducing errors when adequate techniques are used, (b) the need for using confirmatory techniques, and (c) the importance of experience and laboratory resources for optimizing results. The educational aspects of the program for the second year are stressing especially the in situ training of analysts and the supply of solutions of drugs and metabolites to be used as reference standards.