The new calcium antagonist lercanidipine and its enantiomers affect major processes of atherogenesis in vitro: is calcium entry involved?

Atherosclerosis results from multiple factors and involves several mechanisms, including endothelial monocyte and smooth muscle cell (SMC) changes, cholesterol accumulation, plaque rupture and thromboembolism. Calcium ions play a role in the initial and chronic development of atherosclerotic lesions. Several studies in experimental animal models have demonstrated the potential direct antiatherosclerotic effects of calcium antagonists. In this study the antiatherogenic activity of lercanidipine, a new lipophilic, second-generation calcium antagonist, was investigated. Lercanidipine and its enantiomers inhibited the replication and migration of arterial myocytes in concentrations ranging from 10 to 50 microM. The antiproliferative effect of lercanidipine was dose dependent, with a potency similar to that of lacidipine and nifedipine, and was unrelated to the stereoselectivity of enantiomers to bind L-type calcium channels. Lercanidipine and its enantiomers (25 microM) decreased the serum-induced elevation of [Ca2+]i in SMC, with the (S)-enantiomer (69% inhibition) being 2.4-fold more active than the (R)-counterpart (29% inhibition). The studies performed with enantiomers of lercanidipine suggest that the observed effects are not related to the blockade of voltage-dependent Ca2+ channels and confirm, at least in vitro, the pharmacological potential of the compound to influence negatively the process of atherogenesis.

Wilson's disease with concomitant beta thalassaemia and factor V deficiency

A case of late presentation of Wilson's disease in a female with a thalassaemic trait is reported in whom diagnosis of Factor V deficiency was made. Despite ignoring the disease for years the patient had compensated cirrhosis. She had a dramatic family history of Wilson's disease affecting at least two brothers and two sisters. Moreover, her haematologic problems were not clinically revealed until diagnosis had been made on the basis of suspicions arising from laboratory results. The therapy of choice for hepatolenticular degeneration was not feasible due to the patient's refusal. Zinc salts were, therefore, administered. To our knowledge the association of such rare genetic disorders has not been reported.

A significant relationship between plasminogen activator inhibitor type-1 and lipoprotein(a) in non-insulin-dependent diabetes mellitus without complications

We previously found a relationship between plasminogen activator inhibitor type-1 and lipoprotein(a) in non-insulin-dependent diabetes mellitus and hypothesized that this could be due to a compensatory mechanism able to lower the risk of hypofibrinolysis found in type II diabetes mellitus. The aims of the present study were: (1) to confirm the association between plasminogen activator inhibitor type-1 and lipoprotein(a) in a different group of non-insulin-dependent diabetes mellitus patients and (2) to investigate whether the association could be related to diabetic complications. Other vascular risk factors able to influence fibrinolytic parameters such as glycemia, obesity, hypertension, dyslipidemia, and oxidative stress were also considered. Sixty-six non-insulin-dependent diabetes mellitus patients without diabetic complications (48 men, 18 women), 45 non-insulin-dependent diabetes mellitus patients with complications (21 men, 24 women), and 31 control subjects (17 men, 14 women) were studied. Plasma concentrations of lipoprotein(a), plasminogen activator inhibitor type-1 antigen and activity, and the main parameters of lipo- and glycometabolic balance were determined. Antioxidant defense was assayed as oxygen radical absorbance capacity of serum. Statistically significant differences among controls and the two diabetic groups were found for fasting glucose, cholesterol, triglycerides, and oxygen radical absorbance capacity of serum, while no statistically significant differences were evident for plasminogen activator inhibitor type-1 antigen and activity and lipoprotein(a). Regression analysis of log plasminogen activator inhibitor type-1/lipoprotein(a) showed a significant correlation only in diabetic patients without complications (r = -0.57, P < 0.001). These results show that a relationship between plasminogen activator inhibitor type-1 and lipoprotein(a) is characteristic of a diabetic population without complications, supporting the suggestion that this relationship could be a compensatory mechanism of the fibrinolytic system to limit the risks of hypofibrinolysis. A lack or a loss of capacity to balance lipoprotein(a) and plasminogen activator inhibitor type-1 could contribute to the pathogenesis of the diabetic complications.

Super-normal 201Tl retention in hibernating myocardium: an ex-vivo study using the failing human heart

OBJECTIVE

Although the relationship between delayed 201Tl distribution and blood flow in acutely ischemic and infarcted myocardium has been widely explored in the experimental setting, its behaviour in chronically hypoperfused dysfunctioning human myocardium has not yet been evaluated.

METHODS

In tissue samples of excised failing hearts taken from ischemic (IHD) patients and idiopathic dilated cardiomyopathy (IDC) controls, we evaluated the relationship between delayed 201Tl retention (4 h redistribution), blood flow (assessed by means of 99mTc-labelled human albumin microspheres injected during transplantation) and biochemically-assessed fibrosis. 201Tl activity was expressed as the percent of the activity in the region with highest flow and the least fibrosis.

RESULTS

Fibrosis and 201Tl activity were inversely related (r = -0.62, P = 0.0001). In IDC controls, low flows corresponded to uniformly preserved 201Tl retention. In IHD, 46 segments with flows < or = 0.60 ml.min-1.g-1 and 20 segments with flows > 0.60 ml.min-1.g1 showed matching delayed 201Tl retention and flow values; in the remaining 27, there was a disproportionately high tracer accumulation in comparison with flow (flow/201Tl mismatch). Despite significantly less fibrosis and lower flows, the mismatch segments showed significantly greater. 201Tl activity than the segments with concordantly high tracer retention and flow values. Conversely, at equivalent flow rates, the mismatch regions had less fibrosis than the areas with concordantly depressed 201Tl activity and perfusion.

CONCLUSIONS

This super-normal 201Tl retention in hibernating myocardium may indicate a mechanism of cell adaptation to chronic hypoperfusion.

Effects of reduced glutathione and n-acetylcysteine on lidocaine metabolism in cimetidine treated rats

The aim of this work was to evaluate the effects of exogenous glutathione (GSH) and N-acetylcysteine (NAC) on the formation of monoethylglycinexylidide (MEGX) from lidocaine in rats with and without the administration of cimetidine. GSH and NAC were administered intraperitoneally (i.p.) (1 mmol/kg) 1 hour before treatment with cimetidine (0.5 mmol/kg) or saline, and 1 hr later all rats were injected i.p. with lidocaine (1 mg/kg). Blood samples were drawn 30 min after the lidocaine injection. MEGX and lidocaine serum concentrations were determined by means of fluorescence polarization immuno-assay using the TDX system. Cimetidine produced a decrease in MEGX levels (from 210 +/- 18 to 164 +/- 13 ng/mL) and a parallel increase in lidocaine levels (from 73 +/- 22 to 172 +/- 47 ng/mL), consistent with cytochrome P-450 3A inhibition. Both GSH and NAC produce a significant decrease in MEGX levels (151 +/- 16 and 139 +/- 14 ng/mL, respectively), but no significant increase in lidocaine levels were found. As compared to the cimetidine group, pre-treatment using either GSH or NAC with cimetidine produced a marked decrease in lidocaine levels (37 +/- 27 and 63 +/- 28 ng/mL, respectively) and no modification of MEGX levels (155 +/- 12 and 165 +/- 22 ng/mL, respectively). These results suggest that GSH and NAC might accelerate the lidocaine metabolism while counteracting the inhibitory effect of cimetidine.

Which variable of stenosis severity best describes the significance of an isolated left anterior descending coronary artery lesion? Correlation between quantitative coronary angiography, intracoronary Doppler measurements and high dose dipyridamole echocardiography

OBJECTIVES

This study sought to investigate the angiographic or intracoronary Doppler variables of stenosis severity that best correlate with the results of dipyridamole echocardiography.

BACKGROUND

Quantitative coronary angiography and intracoronary Doppler flow velocity assessments are the commonly used techniques for the objective identification of significant coronary artery stenosis.

METHODS

Thirty patients with an isolated lesion of the left anterior descending coronary artery (LAD) were studied by means of on-line quantitative coronary arteriography, intracoronary Doppler flow velocity measurements and dipyridamole echocardiography 6 months after percutaneous transluminal coronary angioplasty. The quantitative arteriographic analyses were performed on-line; post-stenotic Doppler flow velocities were measured at baseline and after adenosine infusion. Angiographic and Doppler measurements were compared with the corresponding dipyridamole echocardiographic data and analyzed by discriminant analysis.

RESULTS

The dipyridamole echocardiographic response was positive in 11 patients (37%). The best cutoff values for predicting an abnormal echocardiographic response were 1) stenotic flow reserve of 2.8 (p = 0.0001); 2) 59% diameter stenosis (p = 0.0001); 3) minimal lumen diameter of 1.35 mm (p = 0.001); 4) coronary flow reserve of 2.0 (p = 0.0002); and 5) maximal peak velocity of 60 cm/s during hyperemia (p = 0.04). Multivariate analysis identified stenotic flow reserve as the only independent predictor of ischemia during dipyridamole echocardiography.

CONCLUSIONS

Stenotic flow reserve is the variable that best describes the functional significance of an isolated LAD lesion, and a value of 2.8 is the best predictor of a positive dipyridamole echocardiographic response. Furthermore, angiographic variables of stenosis severity relate to echocardiographic test results better than intracoronary Doppler variables.

[The recurrence of hepatitic C in orthotopic liver transplantation]

BACKGROUND

This study is a review of hepatitis C recurrence in patients undergoing an orthotopic liver transplantation (OLT); to verify how many patients HCV-positive before OLT confirm a persistent viremia after OLT and how many with viremia show hepatitis histological evidence.

METHODS

Thirty consecutive patients, 24 males, median age 52.5 underwent OLT for posthepatitic C cirrhosis since January 1993 in the "Transplantation Center" of Genoa. Serology included anti-HCV search, HCV-RNA and HBV-DNA determinations, biopses were performed in the transplanted liver within the month after operation, subsequently at every hepatic enzymes increase.

RESULTS

Twenty-one patients are currently alive, median follow-up of 14.5 months. Before OLT anti-HCV antibodies search was positive in all the patients while the HCV-RNA by PCR resulted positive in 17 and negative in 4. Before OLT the HBV-DNA in patients with associated hepatitis B was negative. After OLT 5 patients, of the 17 HCV-RNA positive before OLT, have turned negative then all became again positive from 6 to 12 months later; 2 of the 4 patients HCV-RNA negative before OLT have turned positive, and remained still negative two with hepatitis C associated with hepatitis B. Although viral replication was present in 95% of the patients, clinical and histological evidence of recurrence was ascertained only in 29%.

CONCLUSIONS

It should be noted that the hepatitis histological picture doesn't correspond to a severe worsening of clinical conditions, an evolution justifying transplantation. The long-term results of this therapeutic choice are still uncertain due to the high incidence of recurrences.

Lidocaine elimination and monoethylglycinexylidide formation in patients with chronic hepatitis or cirrhosis

BACKGROUND/AIMS

The aim of this study was to evaluate the relationship between plasma elimination of lidocaine and monoethylglycinexylidide (MEGX) formation, which is considered to be a quantitative liver function test.

METHODOLOGY

The study included ten healthy subjects and 54 patients: 27 with chronic hepatitis and 27 with cirrhosis. Lidocaine and MEGX were measured at 0, 2, 5, 10, 15, 30 min and then every 30 min for 180 min using the TDX system.

RESULTS

In cirrhotic patients, the lidocaine half-life of the slow decline phase of the plasma disappearance curve (beta-HL) and the lidocaine half-life of hepatic elimination from the second compartment (K20-HL) proved to be significantly abnormal, as did all parameters of MEGX formation. In chronic hepatitis, both the lidocaine kinetics and the MEGX formation parameters were within the normal range. In chronic hepatitis patients, MEGX formation (AUC 0-180) was significantly correlated to K20-HL (rs = -0.633, p < 0.001) and to the rapid decline phase of the plasma disappearance curve (alpha-HL, rs = -0.483, p < 0.05). In cirrhotic patients, MEGX was significantly correlated to K20-HL (rs = -0.423, p < 0.05) and to beta-HL (rs = -0.500, p < 0.01).

CONCLUSIONS

These results show that in chronic active hepatitis, MEGX formation from lidocaine is maintained as a metabolic process, whereas it is altered in cirrhotic patients. The interrelationship between lidocaine elimination and MEGX formation were somewhat different in the two liver diseases.

Antagonism to noradrenaline-induced lethality in rats is related to affinity for the alpha1A-adrenoceptor subtype

The potency of several alpha1-adrenoceptor antagonists in preventing the noradrenaline-induced lethality in conscious rats, their binding affinity for the native alpha1A- and alpha1B-adrenoceptors, the recombinant animal alpha1a-, alpha1b- and alpha1d-adrenoceptor subtypes, as well as their functional affinity for the alpha1L-adrenoceptor subtype were evaluated. The potency of the tested compounds as antagonists of noradrenaline-induced lethality was correlated with the affinity for the alpha1A- (and alpha1a-) adrenoceptor subtype, but not with the affinity for the other subtypes. On the contrary, the hypotensive effects of the compounds, assessed in anesthetized rats, were not clearly related with the affinity for any of the alpha1-subtypes. These results suggest that the alpha1A-subtype plays a determining role in preventing lethality induced by noradrenaline in the rats, and that this activity is unrelated to the hypotensive effect of the compounds, which cannot be clearly correlated with affinity for a particular alpha1-adrenoceptor subtype.

Monoethylglycinexylidide formation measurement as a hepatic function test to assess severity of chronic liver disease

OBJECTIVES

Monoethylglycinexylidide (MEGX) is the main lidocaine metabolite and its formation depends on liver microsomal activity. MEGX formation was studied in comparison with the histological score of chronic hepatitis and with the clinical score (Child-Pugh) of cirrhosis. Furthermore, we evaluated its ability to distinguish between the two liver diseases.

METHODS

We studied 284 patients: 130 with chronic hepatitis (on the basis of the histological activity index, 45 had mild chronic hepatitis, 54 had moderate chronic hepatitis, and 31 had chronic hepatitis with cirrhosis) and 154 with cirrhosis (49 Child-Pugh's class A, 78 class B, and 27 class C). MEGX formation was evaluated 15, 30, and 60 min after lidocaine administration.

RESULTS

MEGX formation showed a stepwise decline corresponding to worsened liver disease. MEGX values were related both to the histological score in chronic hepatitis and to the clinical score in cirrhosis. Significantly lower values were found in females < 50 yr of age than in males of the same age. The MEGX test showed great efficacy in discriminating between chronic hepatitis and cirrhosis compared with standard liver tests.

CONCLUSIONS

Measurement of MEGX formation proved to be a safe test, allowing us to show that functional subgroups can be identified both in chronic hepatitis and in cirrhosis. Thus, this test could integrate both the histological grading of chronic hepatitis and the clinical staging of cirrhosis.

Correlation between extent of myocardial dysfunction and markers of irreversible damage in failing hearts

BACKGROUND

The structural correlates of 201Tl uptake in patients with advanced postischemic pump dysfunction are unclear. There are no good experimental models adequately reflecting the mixture of normal, dysfunctional but viable, and necrotic regions characteristic of chronic ischemic heart disease in human beings.

METHODS AND RESULTS

Four heart transplant candidates with idiopathic dilated cardiomyopathy and seven with ischemic heart disease underwent rest-injection 4-hour redistribution 201Tl single-photon emission computed tomography before surgery. Delayed tracer uptake was categorized into severely reduced (<50%), mildly or moderately reduced (50% to 74%), and normal (> or =75%) and related to echocardiographic wall motion and histologic findings in the hearts excised at transplantation. In idiopathic dilated cardiomyopathy, despite severe wall motion impairment, minimal or mild myocardial damage and homogeneously high 201Tl uptake were found. In ischemic heart disease, wall motion did not discriminate extensive from mild structural damage. 201Tl activity was inversely related to myocardial fibrosis (r = -0.50, p = 0.0001). Severe defects in 201Tl uptake (<50%) predicted extensive (>30%) fibrosis with 83% sensitivity and 63% specificity. Segmental akinesis and apical location resulted in loss of sensitivity (74% and 58%, respectively). No histologic or wall motion abnormality accounted for poor specificity. In the individual patient, more than nine segments determined viable by imaging criteria predicted left ventricular fibrosis of less than 15% with 86% accuracy.

CONCLUSIONS

This histopathologic-clinical correlative study supports current evidence of good sensitivity but limited specificity of 201Tl rest-redistribution tomographic imaging in the evaluation of viable myocardium. In the individual patient, more than nine viable segments reliably predicted a limited extension of fibrosis.

Pharmacological characterization of the uroselective alpha-1 antagonist Rec 15/2739 (SB 216469): role of the alpha-1L adrenoceptor in tissue selectivity, part II

The aim of the present work was to investigate whether or not the uroselectivity of Rec 15/2739 and several other alpha-1 adrenoceptor (alpha1-AR) antagonists observed in the anesthetized dog could be related to selectivity of these compounds for a particular alpha-1 AR subtype. The binding affinity of the tested compounds for canine prostate alpha-1 ARs and their in vitro functional affinity for the alpha-1 ARs of rabbit urethra and prostate correlated with their functional affinity for the alpha-1L AR subtype, but not with the binding affinity for recombinant animal and human alpha-1a, alpha-1b and alpha-1d AR subtypes. Similar results were obtained when the in vivo potency on urethral pressure was correlated with the affinity for the alpha-1 AR subtypes; also in this case alpha-1L AR gave the best correlation. No correlation was obtained by considering the other alpha-1 AR subtypes. The in vivo hypotensive effects observed in dog after i.v. administration of the considered compounds correlated only with the binding affinity for the animal and human alpha-1d subtype. In conclusion, the results shown in the present paper indicate that the potencies of different alpha-1 antagonists against the contractions induced by norepinephrine on tissues of the lower urinary tract of rabbits and dogs are better correlated with their affinity for the putative alpha-1L subtype than for the alpha-1a subtype. Only the compounds showing selectivity for the alpha-1L subtype versus the alpha-1d subtype proved highly selective in vivo for the lower urinary tract versus the vascular tissues.

Pharmacological characterization of the uroselective alpha-1 antagonist Rec 15/2739 (SB 216469): role of the alpha-1L adrenoceptor in tissue selectivity, part I

Alpha adrenoceptor antagonists have been convincingly shown to be beneficial in reducing both subjective and objective indices of urethral obstruction in benign prostatic hyperplasia. Rec 15/2739 (SB 216469) is a novel alpha-1 adrenoceptor (alpha-1 AR) antagonist currently being developed for benign prostatic hyperplasia. When evaluated in radioligand binding assays with expressed animal or human alpha-1 ARs, Rec 15/2739 shows marked to moderate selectivity for the alpha-1a AR subtype. Its affinity for the recombinant alpha-2 AR subtypes or native dopaminergic D2 receptor was about 100-fold lower than that for alpha-1a AR subtype. In canine tissues, Rec 15/2739 was 20-fold more potent as an inhibitor of [3H]prazosin binding to prostate vis-a-vis aorta. Functional studies in isolated rabbit tissues also confirmed the uroselectivity of Rec 15/2739, with substantially higher affinity (Kb = 2-3 nM) being observed in urethra and prostate, compared with ear artery and aorta (Kb = 20-100 nM). The in vitro selectivity observed with Rec 15/2739 was confirmed in vivo in the anesthetized dog, comparing potency against norepinephrine- or hypogastric nerve stimulation-induced urethral contraction with its ability to reduce diastolic blood pressure. In this model, Rec 15/2739 had greater selectivity than any other alpha-1 AR antagonist examined, including terazosin and tamsulosin. Based on the low potency of prazosin and some of its structural analogs in the rabbit and dog lower urinary tract tissues, it appears that norepinephrine contracts these tissues via activation of the alpha-1L AR. Hence this alpha-1 AR subtype, rather than the alpha-1A AR, may mediate the contraction in vivo.

Alpha 1-adrenoceptor subtype selectivity: molecular modelling and theoretical quantitative structure-affinity relationships

This study constitutes a preliminary rationalization, at the molecular level, of antagonist selectivity towards the three cloned alpha 1-adrenergic receptor (alpha 1-AR) subtypes. Molecular dynamics simulations allowed a structural/dynamics analysis of the seven alpha-helix-bundle models of the bovine alpha 1a-, hamster alpha 1b-, and rat alpha 1d-AR subtypes. The results showed that the transmembrane domains of these subtypes have different dynamic behaviours and different topographies of the binding sites, which are mainly constituted by conserved residues. In particular, the alpha 1a-AR binding site is more flexible and topographically different with respect to the other two subtypes. The results of the theoretical structural/dynamics analysis of the isolated receptors are consistent with the binding affinities of the 16 antagonists tested towards the three cloned alpha 1-AR subtypes. Moreover, the theoretical quantitative structure-affinity relationships obtained from the antagonist-receptor interaction models further corroborates the hypothesis that selectivity towards one preferential subtype is mainly modulated by receptor and/or ligand distortion energies. In other words, subtype selectivity seems to be mainly guided by the dynamic complementarity (induced fit) between ligand and receptor. On the basis of the quantitative models presented it is possible to predict both affinities and selectivities of putative alpha 1-AR ligands as well as to estimate the theoretical alpha 1-AR subtype affinities and selectivities of existing antagonists.

The acrosome reaction response assay: a new way to identify patients in whom pentoxifylline would improve the human follicular fluid-induced acrosome reaction

The effect of pentoxifylline on the spontaneous and follicular fluid (hFF)-induced acrosome reaction (AR) was studied in an attempt to identify those patients who would benefit from the use of pentoxifylline as an AR-stimulating agent. Pentoxifylline (1 mg/ml) produced no significant increase over spontaneous AR at any of the time points studied (60 min: 6.2% +/- 2.0 spontaneous AR vs 7.4% +/- 2.0 pentoxifylline AR; 120 min: 7.1% +/- 1.6 spontaneous vs 9.0% +/- 2.5 pentoxifylline; 180 min: 7.0% +/- 1.8 spontaneous vs 10.9% +/- 4.0 pentoxifylline, n = 6). On the other hand, hFF produced a significant increase in AR (6.9% spontaneous AR vs 11.2% hFF AR, p < 0.001, n = 39) and this effect was enhanced by pre-incubation with pentoxifylline (15.0% pentoxifylline + hFF AR vs 11.2% hFF AR, p < 0.001). There were no differences in percentage AR induced by hFF or pentoxifylline + hFF between patients with normal (n = 16) and abnormal (n = 25) semen samples. Individual analysis of the effects of hFF and pentoxifylline + hFF on AR showed great variability between patients and enabled us to classify them into four categories: inducible-responder (15%), non-inducible-responder (23%), inducible-non-responder (41%) and non-inducible-non-responder (21%). An induction index (II) (induction produced by hFF divided by spontaneous AR) and a response index (RI) (induction produced by pentoxifylline + hFF divided by hFF) were calculated for each sample. Patients previously classified as inducible exhibited an II > 0.30 and patients previously classified as responders showed an RI > 0.26. There was no correlation between II and RI values (Spearman, r = -0.185, p = 1). Our results show that pentoxifylline is an enhancer of the induced AR only in some patients. We propose an 'AR response assay' to identify responder patients and thus enable rational use of this drug.

Presence of hemoglobinopathies in Sicily: a historic perspective

Sicily, at the center of the Mediterranean, has been the meeting place of Eastern and Western civilizations, and in the Sicilian population the presence of many different alterations in the globin gene clusters can surely be considered testimony of past colonizations. From 1975 to 1994, 100,000 Sicilian subjects were screened by us to monitor the presence of hemoglobin (Hb) structural variants. In this paper we present the data gathered, emphasizing the high incidence (2.5%) of carriers of at least one abnormal Hb, and the great heterogeneity of globin molecular defects on the island. Twenty-six different mutations were identified: the most common occur in the beta-globin gene (beta(S), beta(C), deltabeta(Lepore), beta(G-San José), beta(O-Arab), but also quite frequent is the mutated allele alpha(J-Oxford). The chromosome haplotypes associated with some of them were characterized. Two uncommon Hbs, Copenhagen and D Punjab, and some 18 rare variants complete the wide spectrum of structural alterations of globin genes in Sicily. We think they are de novo mutations prevalently. It is not possible to exclude that the presence of a few of them is related to migratory phenomena, particularly from North Africa and East Asia. Numerous thalassemic alleles complete the picture of globin gene mutations in Silicy.

Determination of vanillylmandelic, 5-hydroxyindoleacetic and homovanillic acid in urine by isocratic liquid chromatography

A new isocratic HPLC method, employing electrochemical detection, is described for the determination of urinary vanillylmandelic acid, 5-hydroxyindoleacetic acid and homovanillic acid. The main advantages of this technique are: simplicity, simultaneous determination of all analytes, the absence of an extraction procedure, isocratic elution and low cost. The diluted urine is injected onto a C18 reversed phase column. The mobile phase is potassium dihydrogenphosphate buffer containing 1-heptanesulphonic acid, methanol and acetonitrile. The calibration curves are linear from 0.1 to 50 mg/l; the precision data show CV less than 2.36% for within-day assay and less than 2.72% for day-to-day assays. The mean recoveries for supplemented samples are 98.2 to 102.0% for vanillylmandelic acid, 99.6 to 103.9% for 5-hydroxyindoleacetic acid and 98.7 to 102.0% for homovanillic acid. In comparisons of the present method with Radjaipur's extraction method (Radjaipur M. et al., Eur J Clin Chem Clin Biochem 1994; 32:609-13) the slopes for the three analytes were nearly 1, and the confidence region of the intercepts was close to 0. In conclusion the technique seems to be suitable for routine determination of the three analytes, especially for mass screening purposes.

Relative levels of alpha-, beta-, and gamma-mRNA from patients with severe and intermediate beta-thalassemia major

We have determined the relative quantities of gamma- and beta-mRNAs and the alpha/beta-mRNA ratios in 37 patients with beta-thalassemia major with specific genotypes, namely 8 with a homozygosity for codon (CD) 39 (C-->T), 7 with a homozygosity for IVS-I-110 (G-->A), 5 with a homozygosity for IVS-I-6 (T-->C), for 15 patients with compound heterozygosities for 2 of these 3 mutations, and for 2 patients with the IVS-I-110 (G-->A)/-87 (C-->G) mutations. None had an alpha-thalassemia. Twelve patients had thalassemia intermedia and the remainder, transfusion-dependent severe conditions. Differences in phenotype were observed for compound heterozygotes involving the IVS-I-6 (T-->C) mutation in combination with either the IVS-I-110 (G-->A) or the CD 39 (C-->T) mutations: patients with thalassemia intermedia had a lower alpha/beta-mRNA ratio, about half of that of the patients with severe beta-thalassemia major. This might suggest a higher beta-mRNA synthesis in some patients than in others with the same genotype; mutations in promoter, enhancer, and/or locus control region sequences may be responsible for these differences. In vitro chain synthesis data were too incomplete to be helpful in this study. The RT-PCR procedure allowed the separation of abnormal (extended) mRNA from normal beta-RNA in subjects carrying the IVS-I-110 (G-->T) mutation. The relative quantities of this beta Th-mRNA (% of beta A + beta Th) were determined by scanning of the appropriate autoradiograms; they averaged 25% for homozygotes and about 4% for heterozygotes, indicating a considerable instability of the message.

[Usefulness of pirenzepine in the study of the upper digestive tract and the large intestine with double contrast media: comparison with scopolamine methylbromide]

The purpose of the present study is to assess the importance of pirenzepine, a selective M1 antimuscarinic drug, as hypotonic agent for diagnostic double-contrast studies of the upper gastrointestinal tract and for double-contrast barium enema studies of the large bowel. Pirenzepine and scopolamine methylbromide (SMB) (Buscopan) were compared in a single blind randomized trial. One hundred-thirty consecutive patients were enrolled in the study. Seventy of them underwent double-contrast studies of the stomach and duodenum and sixty double-contrast barium enema studies of the large bowel. Visceral distension and painting of stomach, duodenal bulb and large bowel and global quality of the images were blindly evaluated by 4 independent observers by means of a numerical score (1 to 4). Quantitative analysis of bowel distension was done measuring the maximum diameter of the transverse colon before and after drug administration. No differences were found in the diagnostic performance between the two drugs in the study of the duodenal bulb (2.8 +/- 0.8 vs 2.9 +/- 0.7, p = NS) and of the large bowel (3.0 +/- 0.6 vs 3.1 +/- 0.6, p = NS). Under SMB, slightly but significantly better results were obtained in the stomach (3.0 +/- 0.6 vs 2.7 +/- 0.6, p = 0.01). However, large bowel distension was slightly but significantly improved with Pirenzepine (68 +/- 12 vs 65 +/- 8 mm, p = 0.02). Heart rate and rhythm during the study were recorded by ECG. SMB induced tachycardia in all patients while pirenzepine did not. Moreover, after SMB, 3 patients exhibited faintness, some patients complained of visual accommodation defects, dryness of the mouth and dizziness. Under pirenzepine, no side-effects were reported. To conclude, pirenzepine gives good results in double contrast studies, as good as SMB but with no adverse effects; thus, it could be proposed as the hypotonic agent of choice in upper gastrointestinal and large bowel examinations.

Effect of the new calcium antagonist lercanidipine and its enantiomers on the migration and proliferation of arterial myocytes

The in vitro effects were investigated of the new dihydropyridine calcium antagonist (CA) lercanidipine and its enantiomers on arterial myocyte (smooth muscle cell; SMC) migration and proliferation as related to L-type calcium channel inhibition. Lercanidipine and its enantiomers inhibited the replication and migration of arterial myocytes in concentration ranging from 10 to 50 microM. The antiproliferative effect of lercanidipine, evaluated as cell number, was dose dependent, with a potency similar to that of lacidipine and nifedipine, and was unrelated to the stereoselectivity of enantiomers to bind L-type calcium channels. The cell doubling time increased with drug concentration < or = 122 versus 38 h for controls. The cell growth inhibition induced by lercanidipine and its enantiomers was reversible. Lercanidipine dose dependently decreased [3H]thymidine incorporation into DNA; the (R)-enantiomer, displaying the lowest CA activity, was the most potent in this respect. The tested compounds were able to inhibit fibrinogen-induced myocyte migration in a dose-dependent manner, with the (R)-enantiomer showing the more pronounced effect. To directly rule out the role of calcium channels in the antiatherosclerotic properties of lercanidipine, we examined the effect of the compounds on serum-stimulated calcium influx in SMC. Fluorimetry of Fluo 3 was used to measure changes in free cytosolic Ca2+ concentration ([Ca2+]i) in SMC after long-term preincubation (24 h) with the tested CA. Lercanidipine and its enantiomers (25 microM) decreased the serum-induced elevation of [Ca2+]i in SMC with the (S)-enantiomer (69% inhibition) 2.4-fold more active than the counterpart and the racemate (29% inhibition). In conclusion, our in vitro results suggest that lercanidipine may directly interfere with events involved in atherogenesis. The studies performed with enantiomers of lercanidipine suggest that the observed effects are not related to the blockade of voltage-dependent Ca2+ channels and confirm at least in vitro a pharmacologic potential of the compound to negatively influence the process of atherogenesis.

Pirenzepine versus scopolamine methyl bromide in double-contrast barium enema study of large bowel

To evaluate the usefulness of pirenzepine for diagnostic double-contrast barium enema study of the large bowel, pirenzepine and scopolamine methyl bromide (SMB) were compared in a single, blind, randomized trial. Sixty consecutive patients were enrolled in the study. Quantitative analysis of bowel distention was done by measuring the maximum diameter of the transverse colon before and after drug administration. Four independent observers blindly evaluated distention and mucosal coating of the large bowel and global quality of the images. No differences were found in the diagnostic performance between the two drugs. However, pirenzepine induced a slight but significantly larger distention of the large bowel (68 +/- 12 vs. 65 +/- 8 mm, p = 0.02). Heart rate and rhythm during the study were recorded by ECG. SMB induced tachycardia in all patients (from 72 +/- 15 to 98 +/- 24 beats/min, p < 0.01), whereas pirenzepine did not (from 76 +/- 13 to 78 +/- 20, p = NS). After SMB, one-patient exhibited faintness, and some patients complained of visual accommodation defects, dryness of the mouth, and dizziness. Pirenzepine had a diagnostic performance similar to SMB in avoiding adverse effects elicited by SMB.

Relationship between plasminogen activator inhibitor type-1 plasma levels and the lipoprotein(a) concentrations in non-insulin-dependent diabetes mellitus

The first part of the paper deals with the relationship between two inhibiting factors of the complex enzyme cascade regulating fibrinolysis, namely plasminogen activator inhibitor type-1 (PAI-1) and lipoprotein(a) (Lp(a)). Blood concentrations of Lp(a), PAI-1 antigen (PAI-1 AG) and activity (PAI-1 AT), and the main parameters of lipo- and glyco-metabolic balance were studied in 80 type II diabetic patients. Roughly hyperbolic patterns have been found between PAI-1 and Lp(a). Negative statistically significant linear correlation can be elicited when Log PAI-1 AG and Log PAI-1 AT values are plotted versus Lp(a) values, the first one being particularly tight. These findings suggest a nearly on/off control of the two parameters, limiting the risk of hypofibrinolysis. The second part of the paper was aimed at verifying this hypothesis. A group of 30 diabetic patients were treated for 3 months with metformin, an antidiabetic biguanide compound which has been reported to reduce PAI-1 levels both in diabetic and in non-diabetic patients. Metformin significantly reduced PAI-1 AG and PAI-1 AT but did not influence plasma Lp(a) levels. A clear linear correlation between the basal Lp(a) values and the changes in PAI-1 AG levels was found. An even tighter correlation was elicited between the decrease in PAI-1, and PAI-1 pretreatment values.

Morphological bases for thallium-201 uptake in cardiac imaging and correlates with myocardial blood flow distribution

To determine the morphological bases of thallium-201 myocardial distribution in chronic cardiac dysfunction and their relation to myocardial blood flow, myocardial slices from ten excised hearts of five chronic ischaemic heart disease patients and five idiopathic dilated cardiomyopathy patients, were imaged on a gamma camera to quantitate the uptake of thallium-201, injected 4 h before surgery, and myocardial blood flow from distribution of technetium-99m-labelled human albumin microspheres injected during surgery. Tracer distribution was correlated with histologically assessed myocardial fibrosis and myocytolysis. Thallium-201 uptake was inversely related to fibrosis (r = -0.73, in ischaemic heart disease, r = -0.65 in idiopathic dilated cardiomyopathy). In ischaemic heart disease, myocardial blood flow was related neither to thallium-201 uptake (r = 0.41) nor to the extent of fibrosis (r = -0.48). In this group, segments with normal or mildly reduced thallium-201 uptake showed significantly lower fibrosis than those with moderate or severe uptake defects (5 +/- 7% and 7 +/- 11% vs 33 +/- 14% and 42 +/- 12%, respectively, P < 0.0001. In a clinical model of chronic ischaemic dysfunction, despite severely depressed myocardial blood flow, extensive areas of myocardium devoid of significant structural impairment are present. Thallium-201 uptake effectively discriminates regions with preserved viability from those with relevant myocardial damage.

Functional antagonistic activity of Rec 15/2739, a novel alpha-1 antagonist selective for the lower urinary tract, on noradrenaline-induced contraction of human prostate and mesenteric artery

The aim of this study was to compare with known reference standards the functional in vitro alpha-1 antagonistic activity of Rec 15/2739 on noradrenaline-induced contractions of human prostate and mesenteric artery. We also characterized these tissues with regard to the alpha-1 adrenoceptor subtypes present. Comparing the apparent pKB values revealed Rec 15/2739 to be one of the most potent compounds action on the prostate. Its potency was slightly lower than that of tamsulosin and was higher than the potencies of prazosin, terazosin and 5-methylurapidil. On the mesenteric artery, tamsulosin was the most potent compound. Comparing the results from the functional studies with those obtained from radioreceptor binding studies, we found that the potency (pKB value) in inhibiting the contraction of prostatic tissue showed a close and significant correlation with the affinity for native and recombinant alpha-1A adrenoceptors. No significant correlation was found with affinity for either the native or the recombinant alpha-1B adrenoceptor subtype, or for recombinant alpha-1d receptors. Similar results were obtained for mesenteric artery. In order to characterize further the alpha-1 adrenoceptor subtypes present in the examined tissues, we investigated the functional effects of chloroethylclonidine, an alpha-1B-D subtypes selective alpha-1 adrenoceptor irreversible antagonist, and those of nifedipine, which antagonizes the extracellular calcium influx primarily mediated by alpha-1A adrenoceptor stimulation. The results indicate the presence of both chloroethylclonidine-sensitive and -insensitive alpha-1 adrenoceptor subtypes in the human prostate, whereas in mesenteric artery the alpha-1A subtype seems to be present exclusively. The possibility that the functionally relevant alpha-1 adrenoceptor subtype could be classified as alpha-1L in both tissues shoul also be considered.