Sulfhydryl redox state affects susceptibility to ischemia and sarcoplasmic reticulum Ca2+ release in rat heart. Implications for ischemic preconditioning

We investigated the effect of sulfhydryl and disulfide reagents on ischemic preconditioning and on sarcoplasmic reticulum Ca2+ release. Isolated working rat hearts were subjected to ischemic preconditioning (three 3-minute periods of global ischemia) or to control aerobic perfusion, which was followed by 30 minutes of global ischemia and 120 minutes of retrograde reperfusion. Necrosis was evaluated on the basis of lactate dehydrogenase release and triphenyltetrazolium chloride staining. In parallel experiments, sarcoplasmic reticulum Ca2+ release and [3H]-ryanodine binding were determined before the sustained ischemia. Ischemic preconditioning was associated with protection versus ischemic injury, decreased Ca2+ release and reduced [3H]-ryanodine binding. The disulfide reducing agent dithiothreitol (1 mmol/L) removed the protection provided by ischemic preconditioning, if added to the perfusion buffer either before or after the preconditioning procedure. In preconditioned hearts, dithiothreitol increased sarcoplasmic reticulum Ca2+ release and ryanodine binding, whereas in control hearts it had no effect on either tissue injury or sarcoplasmic reticulum function. Perfusion of control hearts with the sulfhydryl blocking agents 4,4'-dithiodipyridine (25 micromol/L) and N-ethylmaleimide (16 micromol/L) increased the resistance to ischemia and reduced sarcoplasmic reticulum Ca2+ release and [3H]-ryanodine binding. These effects were not additive with those induced by preconditioning. Sulfhydryl and disulfide reagents produced similar effects on Ca2+ release and [3H]-ryanodine binding if added in vitro to preparations obtained from control and preconditioned hearts. We conclude that ischemic preconditioning is associated with the oxidation of sulfhydryl groups involved in the modulation of sarcoplasmic reticulum Ca2+ release.

Coronary collateral circulation behaviour and myocardial viability in chronic total occlusion treated with coronary angioplasty

AIMS

We explored the role of microcirculation integrity following the chronic occlusion of an infarct-related artery to assess the behaviour of collateral circulation during and after reperfusion by coronary angioplasty

METHODS AND RESULTS

Eighteen patients with a proximally occluded left anterior descending artery and firm evidence of intercoronary collateral circulation were studied with selective coronary angiography and selective intracoronary myocardial contrast echocardiography, before coronary angioplasty, and at 5 and 15 min and 12 h later. Myocardial enhancement during myocardial contrast echocardiography was evaluated with a semiquantitative score (0-3), which was correlated to basal and 6 months' regional left ventricular wall motion results. 16/18 procedures were successfully performed; four patients with an inadequate acoustic window were excluded. Restenosis was evident at the 6 months' follow-up in two patients. Basal myocardial contrast echocardiography indicated that 81/192 segments from the left anterior descending coronary artery and 90/192 from the right coronary artery were perfused; no perfusion was observed in 21 segments either before or after coronary angioplasty. After coronary angioplasty, the angiographic intercoronary collateral circulation immediately disappeared, and myocardial contrast echocardiography revealed that there was a progressive reduction of segments perfused by the right coronary artery and an increase in segments perfused by the left anterior descending coronary artery. Regional left ventricular wall motion analysis demonstrated that there was abnormal motion in 51/192 segments. There was no improvement in segments with score 0 and abnormal motion after 6 months (100% sensitivity), but 16/17 segments with score 3 did show an improvement (98% specificity). The predictive value of intermediate scores (1-2) in detecting long-term improvement, was only 43%.

CONCLUSION

These data show that the adaptive mechanism observed in the behaviour of epicardial and microvascular circulation after reperfusion of a chronic occluded infarct-related artery can vary. In addition, this study clearly shows that microvascular integrity detected by myocardial contrast echocardiography can provide myocardial viability.

A competitive enzyme-linked immunosorbent assay for measuring the levels of serum antibody to Haemophilus influenzae type b

A competitive ELISA method is described for the measurement of total antibodies to the capsular polysaccharide of Haemophilus influenzae type b (HibCPS) in human sera. The competitive method showed an excellent correlation to the radioantigen binding assay (RABA, or Farr assay) and improved correlation of sera with low titers with respect to the more conventional noncompetitive method. Overestimation of samples in the low concentration range was no longer observed with the competitive ELISA method. The free HibCPS competition allowed us to eliminate the day-to-day background variation typical of some sera; thus, only values representing the true anti-HibCPS response were determined. The use of precoated microplates, which could be stored up to 8 months, greatly improved the speed of the procedure. An overall correlation coefficient of 0. 9660 was found when 407 serum samples with a wide variety of anti-HibCPS antibody levels were tested with the competitive ELISA and RABA. The regression line was very close to the ideal line, with a slope of 1.0045 and an intercept of -0.1996. A subset of 96 serum samples representative of all pre- and postimmunization samples was used to compare the competitive ELISA with a previously described ELISA method. The competitive method performed in two laboratories in different countries showed a better correlation with the RABA. The correlation factors were 0.9770 and 0.9816, respectively, while a factor of 0.9547 was found with the previously described noncompetitive procedure, which was better for this method than previously reported (r = 0.917). Therefore, the competitive ELISA is proposed for the assay of anti-HibCPS titers in sera from vaccinated subjects.

Identification and characterization of a novel serine-threonine kinase gene from the Xp22 region

Eukaryotic protein kinases are part of a large and expanding family of proteins. Through our transcriptional mapping effort in the Xp22 region, we have isolated and sequenced the full-length transcript of STK9, a novel cDNA highly homologous to serine-threonine kinases. A number of human genetic disorders have been mapped to the region where STK9 has been localized including Nance-Horan (NH) syndrome, oral-facial-digital syndrome type 1 (OFD1), and a novel locus for nonsyndromic sensorineural deafness (DFN6). To evaluate the possible involvement of STK9 in any of the above-mentioned disorders, a 2416-bp full-length cDNA was assembled. The entire genomic structure of the gene, which is composed of 20 coding exons, was determined. Northern analysis revealed a transcript larger than 9.5 kb in several tissues including brain, lung, and kidney. The mouse homologue (Stk9) was identified and mapped in the mouse in the region syntenic to human Xp. This location is compatible with the location of the Xcat mutant, which shows congenital cataracts very similar to those observed in NH patients. Sequence homologies, expression pattern, and mapping information in both human and mouse make STK9 a candidate gene for the above-mentioned disorders.

Transvascular and urinary leakage of albumin in atherosclerotic and hypertensive men

Increased urine albumin is associated with atherosclerotic disease and predicts cardiovascular morbidity and mortality in nondiabetic populations. This finding is frequently postulated to reflect the impact of atherosclerotic damage on glomerular and systemic capillary permeability, an interesting but as yet untested hypothesis. The transcapillary escape rate of albumin (TERalb, the 1-hour decline rate of intravenous 125I-albumin, a measure of capillary macromolecular permeability), albuminuria, lipid levels, echocardiographic wall thickness, and insulin responses to oral glucose were measured in 30 untreated dipstick-negative lean men and clinically stable atherosclerotic peripheral vascular disease; tolerance to oral glucose was a requirement for inclusion in the study. Because hypertension per se might influence TERalb, the sample included either normotensive (n=18, 118+/-6/72+/-7 mm Hg) or hypertensive (n=12, 141+/-7/84+/-6 mmHg by 24-hour blood pressure monitoring) arteriopathic patients; 11 normal age- and gender-matched subjects (121+/-7/76+/-5 mmHg) were used as control subjects. TERalb was higher in patients (10.7+/-3.2 versus 7.4+/-1.7%/h, P<0.013), a difference that persisted after postload glucose, insulin, and lipid levels were accounted for by covariance analysis; atherosclerosis and hypertension together did not further impair vascular permeation to albumin. In contrast with TERalb, albuminuria was elevated only in the hypertensive subgroup; the 2 variables showed no relationship, even when the data were analyzed separately in normotensive and hypertensive subgroups. Urine albumin correlated positively with 24-hour blood pressure and wall thickness. Thus, systemic capillary permeability is altered in nondiabetic atherosclerotic patients independently from blood pressure levels, but this abnormality is not reflected by proportionate changes in albuminuria.

Characterization of Cxorf5 (71-7A), a novel human cDNA mapping to Xp22 and encoding a protein containing coiled-coil alpha-helical domains

The human X chromosome is known to contain several disease genes yet to be cloned. In the course of a project aimed at the construction of a transcription map of the Xp22 region, we fully characterized a novel cDNA, Cxorf5 (HGMW-approved symbol, alias 71-7A), previously mapped to this region but for which no sequence information was available. We isolated and sequenced the full-length transcript, which encodes a predicted protein of unknown function containing a large number of coiled-coild domains, typically presented in a variety of different molecules, from fibrous proteins to transcription factors. We showed that the Cxorf5 cDNA is ubiquitously expressed, undergoes alternative splicing, and escapes X inactivation. Furthermore, we precisely mapped two additional Cxorf5-related loci on the Y chromosome and on chromosome 5. By virtue of its mapping assignment to the Xp22 region, Cxorf5 represents a candidate gene for at least four human diseases, namely spondyloepiphiseal dysplasia late, oral-facial-digital syndrome type 1, craniofrontonasal syndrome, and a nonsyndromic sensorineural deafness.

[Deep venous thrombosis: epidemiologic, diagnostic and therapeutic aspects]

Deep vein thrombosis (DVT) has a high social and economic cost disease being its prevalence in the general population elevated and producing possibly fatal (pulmonary embolism) or disabling (post-thrombotic syndrome) complications. Thus, it appears of great importance to know the epidemiological and clinical characteristics of DVT in order to perform the best diagnosis, therapy and prophylaxis. The study population is composed by 146 patients (84 males and 62 females, mean age 60.9 +/- 15.3 years, range 19.92 years), arrived in our Vascular Echography Laboratory with the clinical suspect of DVT confirmed by means of echo color Doppler. The most frequent clinical signs were skin hyperthermia in 118 patients (80.8%) and edema in 116 patients (79.5%), while the most common symptom was pain, 89 patients (61.0%). Eleven patients (7.5%) were asymptomatic. The echo criteria utilized were direct thrombus visualization, vessel diameter higher than the contralateral, reduced or absent vessel wall ability to be compressed, reduced or absent color Doppler venous flow, lack or reduction of respiratory flow modulation, visualization of collateral circulation. DVT was located in 131 patients (89.7%) in inferior limbs (proximal in 122 patients, isolated distal in 9 patients), in 14 patients (9.6%) in superior limbs and in 3 patients (2.1%) in the internal jugular vein. In 130 patients a risk factor or a predisposing condition was identified: secondary DVT; in 16 patients the DVT was considered idiopathic. The most frequent risk factors were: previous surgery 28.1%, immobilization 19.9% trauma 17.1%, tumors 9.6%. A hypercoagulation was detected in 4 patients: antithrombin III deficit in 2, post-splenectomy thrombocytosis in 1 and antiphospholipid antibodies syndrome in the last one. The Pisa territory epidemiologic data showed a male 0.51 and female 0.38/1000 subject/year DVT incidence, with significantly higher values in older than 45-54 males and 55-64 females. One hundred and thirty one patients were treated with 5-11 day heparin infusion and thereafter with warfarin at least for 6 months, 1 year or indefinitely depending on thromboembolic risk. Six patients with distal DVT and 9 patients with hemorrhagic risk were treated with subcutaneous calcic or low weight heparin. In 1 patient with a mobile thrombus judged as at very high risk of embolization, a caval filter was positioned. Anticoagulant therapy complications were: 2 minor bleedings, 1 alopecia, 1 thrombocytopenia. Two patients died for neoplastic complications. Fifty-seven patients completed a 6-month follow-up and were submitted to a control each study that evidenced: total recanalization in 15 (26.3%), partial recanalization in 25 (43.9%) and no recanalization in 17 patients (29.8%). In 6 patients there was a DVT relapse and in 9 pulmonary embolization: almost all these patients were in the partial recanalization group.

Epithelial V-like antigen (EVA), a novel member of the immunoglobulin superfamily, expressed in embryonic epithelia with a potential role as homotypic adhesion molecule in thymus histogenesis

Thymus development depends on a complex series of interactions between thymocytes and the stromal component of the organ. To identify regulated genes during this codependent developmental relationship, we have applied an RNA fingerprinting technique to the analysis of thymus expansion and maturation induced in recombinase-deficient mice injected with anti-CD3 antibodies. This approach led us to the identification of a gene encoding a new member of the immunoglobulin superfamily, named epithelial V-like antigen (EVA), which is expressed in thymus epithelium and strongly downregulated by thymocyte developmental progression. This gene is expressed in the thymus and in several epithelial structures early in embryogenesis. EVA is highly homologous to the myelin protein zero and, in thymus-derived epithelial cell lines, is poorly soluble in nonionic detergents, strongly suggesting an association to the cytoskeleton. Its capacity to mediate cell adhesion through a homophilic interaction and its selective regulation by T cell maturation might imply the participation of EVA in the earliest phases of thymus organogenesis.

Aneuploidy and diploidy rates in sperm of five men after three-colour hybridization: indication of X chromosome-associated autosome 2 aneuploidy

The frequencies of aneuploidy and diploidy for chromosomes 2, X and Y in sperm nuclei of five nonsmoking normal donors were assessed by three-colour fluorescence in situ hybridization. We detected neither significant interindividual variability nor age effect (age range of the study group: 26-38 yr) on the mean frequencies of aneuploid and diploid sperm. Nullisomic sperm were observed more frequently than disomic sperm. In addition, sex chromosomal meiotic nondisjunction occurred at a higher rate than autosomal nondisjunction, and disomic sperm for the sex chromosomes were formed mainly by errors in the second meiotic division. Our data indicate that diploidy occurs at a very low frequency in comparison with aneuploidy. Furthermore, the overall proportion of X-bearing sperm nuclei aneuploid for chromosome 2 is significantly higher than that of Y-bearing sperm (0.14% vs. 0.05%, respectively; p < 0.001). This finding adds further evidence that autosomal aneuploidy can be preferentially associated with the presence of one of the two gonosomes.

Predicting outcome after myocardial revascularization in patients with left ventricular dysfunction

In order to identify the risk factors which could predict outcome after coronary artery bypass grafting in patients with left ventricular dysfunction, 80 consecutive patients with an ejection fraction < or = 30%, who underwent isolated coronary artery bypass grafting at the authors' centre between January 1994 and May 1996 were evaluated. Preoperatively, mean(s.d.) ejection fraction was 27.1(3.8)%, 56 patients (70%) had angina, and 56(70%) were in New York Heart Association (NYHA) functional class III or IV. There were five operative deaths, with a hospital mortality rate of 6.3%. Significant risk factors for hospital death were NYHA class IV, preoperative ventricular arrhythmias and left ventricular end-diastolic volume index > 110 ml/m2. At mean follow-up of 15(7) (range 6-30) months, there were six late deaths, five of which were from cardiac causes. Actuarial survival rate at 2 years was 82(5)% and freedom from cardiac death 84(5)%. Risk factors for overall mortality from cardiac causes were preoperative grade 2 mitral regurgitation, associated with left ventricular dilatation, and renal dysfunction (creatininaemia > or = 180 micromol/l). At follow-up, mean ejection fraction was 37.5(8.4)%, and the overall functional status had improved: 12 patients (18%) had angina and eight (12%) were in NYHA class III and IV. Myocardial revascularization in patients with left ventricular dysfunction can be performed with acceptably low operative risk, good survival rate at 2 years, and functional status improvement. Patients with extensive ventricular dilatation, associated with significant mitral regurgitation, have a lower life expectancy and less functional benefits from coronary artery bypass grafting. These patients are better treated by cardiac transplantation.

Altered autonomic cardiac control in hypertrophic cardiomyopathy. Role of outflow tract obstruction and myocardial hypertrophy

AIM

The goal of this study was to investigate the role of left ventricular outflow tract obstruction and myocardial hypertrophy on autonomic cardiac function in patients with hypertrophic cardiomyopathy.

METHODS AND RESULTS

The sympatho-vagal function was evaluated by spectral analysis of heart rate variability in 28 patients with hypertrophic obstructive cardiomyopathy, 22 patients with hypertrophic non-obstructive cardiomyopathy, 12 with systemic hypertension and left ventricular hypertrophy and 28 healthy subjects. Left ventricular out-flow tract pressure gradient in patients with hypertrophic cardiomyopathy was evaluated by echo-Doppler methods and the quantitative assessment of left ventricular hypertrophy was based on an echocardiographic index. At rest, patients with hypertrophic non-obstructive cardiomyopathy showed normal spectral patterns, while in patients with hypertrophic obstructive cardiomyopathy and in patients with systemic hypertension we observed, respectively, a significant reduction and increase in the low frequency component relative to the control (P < 0.05). During tilt, the physiological increases in the low frequency component and in the low to high frequency ratio were markedly blunted, or even reverted, only in patients with hypertrophic obstructive cardiomyopathy. In these patients, the heart rate increase during tilt was delayed in comparison to the other groups. Finally, in the hypertrophic obstructive cardiomyopathy group, the impairment of sympathetic activation (lack of increase in the low frequency component during tilt) was significantly correlated to the echocardiographic index of left ventricular hypertrophy (r = -0.800, P < 0.001) rather than to the left ventricular outflow tract pressure gradient (r = 0.295, P: ns).

CONCLUSION

Among patients with hypertrophic cardiomyopathy, only those with outflow tract obstruction show spectral signs of altered autonomic cardiac control. Within this group, the autonomic dysfunction appears to be correlated to myocardial hypertrophy rather than to left ventricular outflow tract obstruction.

Severe hypoxia enhances the formation of erythroid bursts from human cord blood cells and the maintenance of BFU-E in vitro

Incubation in severe hypoxia (1% oxygen) increased the number of erythroid bursts generated from full-term CD34+, or premature mononucleated, human cord blood (CB) cells, in semisolid cultures containing stem cell factor (SCF), interleukin (IL)-3 and erythropoietin (EPO). Severe hypoxia also enhanced the maintenance of erythroid burst-forming units (BFU-E) in CB cell liquid cultures. These positive effects of hypoxia on the maintenance and cloning efficiency of BFU-E did not extend to the other progenitors assayed. Hypoxia, on the other hand, markedly reduced the size and level of hemoglobinization of bursts and, in liquid cultures, suppressed the growth factor-stimulated numerical increase in BFU-E and inhibited the expression of CD36, a marker of erythroid colony-forming units and maturing erythroid precursors. However, when transferred to clonal assays incubated in air, cells from liquid cultures incubated in hypoxia or in air generated fully expanded and hemoglobinized bursts, suggesting that in hypoxia the clonogenic potential of BFU-E was maintained and the development of erythroid clones reversibly inhibited. These results indicate that hypoxia inversely regulates two subsequent phases of erythropoiesis, i.e., it enhances the maintenance of BFU-E and the early development of erythroid clones but inhibits the terminal expansion and maturation of these clones. The cloning of CB cells selected for CD34 positivity, when compared with that of the total population of mononucleated CB cells, revealed that the early development of erythroid bursts was either hypoxia-enhanced or hypoxia-insensitive, reflecting the existence of two different types of BFU-E. Hypoxia-enhanced BFU-E are relatively immature, are maintained in hypoxia but not in air, and account for a large part of CD34+ BFU-E and for a high percentage of the BFU-E in premature CB. Hypoxia-insensitive BFU-E are mostly CD34- and are largely predominant in full-term CB, and most probably correspond to a more mature type of BFU-E.

The role of phenylalanine 31 in maintaining the conformational stability of ribonuclease P2 from Sulfolobus solfataricus under extreme conditions of temperature and pressure

Ribonuclease P2 from the thermophilic archaebacterium Sulfolobus solfataricus is a small protein (7 kDa) with a known three-dimensional structure. Inspection of the structure and molecular dynamics simulation reveal that three aromatic residues (Phe5, Phe31, and Tyr33) from the hydrophobic core have a strong van der Waals interaction energy. We studied the thermodynamics of the heat, cold, and pressure-induced protein conformational changes of the wild type and of the F31A and F31Y mutants by analyzing the protein UV absorbance in the fourth derivative mode. The wild-type protein was extremely stable under all conditions of temperature and pressure. Heat and cold denaturation of both mutants, as well as denaturation by pressure of the F31A mutant, led to significant blue shifts of the derivative spectrum, indicating increased solvent exposure of Tyr33. For the F31Y mutant, high pressure (400 MPa) protected the protein against thermal denaturation. This study, probing the properties of the hydrophobic aromatic core, complements a thermal unfolding study which probes the overall structural changes [Knapp, S., Karshikoff, A., Berndt, K. D., Christova, P., Atanasov, B., & Ladenstein, R. (1996) J. Mol. Biol. 264,1132-1144]. The differences observed in response to extremes of temperature, pressure, and pH may be rationalized by an unfolding mechanism involving larger parts of the peripheral protein while the integrity of the hydrophobic core is maintained.

Dose-finding study and pharmacokinetics of epirubicin and paclitaxel over 3 hours: a regimen with high activity and low cardiotoxicity in advanced breast cancer

PURPOSE

To determine the maximum-tolerated dose (MTD) of paclitaxel over 3 hours with a fixed dose of epirubicin, to investigate the plasma pharmacokinetics of this combination, and to evaluate the toxicity and the activity in previously untreated metastatic breast cancer patients.

PATIENTS AND METHODS

Fifty patients with metastatic breast cancer, measurable disease, and normal left ventricular ejection fraction (LVEF) were eligible. Epirubicin was administered as an intravenous (I.V.) bolus at the fixed dose of 90 mg/m2 before the infusion of paclitaxel over 3 hours. The initial dose of paclitaxel was 135 mg/m2 and was increased by 20 mg/m2 in subsequent cohorts of six patients until dose-limiting toxicity (DLT). Plasma pharmacokinetics of paclitaxel and epirubicin was performed at cycle 1 in at least two patients per dose level of paclitaxel (175 up to 225 mg/m2).

RESULTS

The DLT of this combination was febrile neutropenia in two of eight patients who received paclitaxel at 225 mg/m2. The mean peak plasma concentration of paclitaxel ranged between 5.1 and 6.2 micromol/L at doses of 175 to 225 mg/m2. The concentration of epirubicinol decreased from 47.3 +/- 9.4 to 37.9 +/- 7.5 ng/mL in patients treated with paclitaxel 175 and 225 mg/m2. The most relevant toxicity was grade 4 neutropenia (61% of all courses). The pharmacokinetic data of paclitaxel, in particular the time above the threshold level of 0.05 micromol/L, were not significantly related to myelosuppression. Cardiac toxicity was mild: three patients (6%) developed mild congestive heart failure that was responsive to therapy. Among 49 assessable patients, 41 responses (84%; 95% confidence interval [CI], 70% to 92%) were observed, and nine (18%) of these were complete.

CONCLUSION

Our study demonstrates that (1) the MTD is epirubicin 90 mg/m2 and paclitaxel 200 mg/m2; (2) no clear relationship exists between pharmacokinetic data of paclitaxel and myelosuppression, while the increase in the dose of paclitaxel is associated with a reduction in epirubicinol plasma levels; and (3) the association is feasible, with low cardiotoxicity, and has a high activity in metastatic breast cancer.

A novel human serine-threonine phosphatase related to the Drosophila retinal degeneration C (rdgC) gene is selectively expressed in sensory neurons of neural crest origin

Through our transcriptional mapping effort in the Xp22 region, we have isolated by exon trapping a new transcript highly homologous to the Drosophila retinal degeneration C (rdgC) gene. rdgC encodes a serine/threonine phosphatase protein and is required in Drosophila to prevent light-induced retinal degeneration. This human gene is the first mammalian member of the serine-threonine phosphatase with EF hand motif gene family, and was thus named PPEF (Protein Phosphatase with EF calcium-binding domain). The expression pattern of the mouse Ppef gene was studied by RNA in situ hybridization on embryonic tissue sections. While rdgC is expressed in the visual system of the fly, as well as in the mushroom bodies of the central brain, we found that Ppef is highly expressed in sensory neurons of the dorsal root ganglia (DRG) and neural crest-derived cranial ganglia. The selective pattern of expression makes PPEF an important marker for sensory neuron differentiation and suggests a role for serine-threonine phosphatases in mammalian development.

[Myocardial revascularization in patients with ischemic cardiomyopathy and left ventricular dysfunction]

In this study we evaluated the outcome of coronary artery bypass grafting (CABG) in patients with coronary artery disease and left ventricular dysfunction. The aim of the study was to identify the risk factors for operative and medium-term mortality. We evaluated 117 consecutive patients (98 men, 19 women, aged 42 to 84 years, mean 65 +/- 9) with ejection fraction (EF) < 40%, operated on from January 1994 to December 1995. Patients who had previously undergone CABG, or who had other procedures associated with CABG, were excluded. Preoperatively, mean EF was 32 +/- 5%; 65 patients (56%) had angina and 62 (53%) had congestive heart failure in NYHA functional class III and IV. Hospital mortality rate was 5% (i.e. 6 deaths). At multivariate analysis significant risk factors were: NYHA functional class IV and moderate/ severe mitral regurgitation. All patients were evaluated at a mean follow-up time of 13 +/- 8 months (range 3 to 30); 9 deaths occurred, 7 due to cardiac causes. Actuarial survival rate at 24 months was 85 +/- 4%; freedom from death due to cardiac causes was 87 +/- 4%. Significant risk factors for medium-term mortality at multivariate analysis were age, moderate/severe mitral regurgitation and marked impairment of regional myocardial contractile function, evaluated by the wall motion score index (> or = 2.25). At follow-up the majority of patients showed improved clinical conditions: mean EF was 40 +/- 8%; 8 patients (8%) had angina and 12 (12%) were in NYHA functional class III and IV. Myocardial revascularization in patients with coronary artery disease and left ventricular dysfunction is characterized by low operative risk and good survival rate at 2 years, with improvement of both angina and congestive heart failure. The best results were obtained in those patients who preoperatively showed the best regional contractile function, even though the global EF was poor, and in those with signs of reversible left ventricular dysfunction, such as angina or documented myocardial viability.

The solution structure of serine protease PB92 from Bacillus alcalophilus presents a rigid fold with a flexible substrate-binding site

BACKGROUND

Research on high-alkaline proteases, such as serine protease PB92, has been largely inspired by their industrial application as protein-degrading components of washing powders. Serine protease PB92 is a member of the subtilase family of enzymes, which has been extensively studied. These studies have included exhaustive protein engineering investigations and X-ray crystallography, in order to provide insight into the mechanism and specificity of enzyme catalysis. Distortions have been observed in the substrate-binding region of subtilisin crystal structures, due to crystal contacts. In addition, the structural variability in the substrate-binding region of subtilisins is often attributed to flexibility. It was hoped that the solution structure of this enzyme would provide further details about the conformation of this key region and give new insights into the functional properties of these enzymes.

RESULTS

The three-dimensional solution structure of the 269-residue (27 kDa) serine protease PB92 has been determined using distance and dihedral angle constraints derived from triple-resonance NMR data. The solution structure is represented by a family of 18 conformers which overlay onto the average structure with backbone and all-heavy-atom root mean square deviations (for the main body of the molecule) of 0.88 and 1.21 A, respectively. The family of structures contains a number of regions of relatively high conformational heterogeneity, including various segments that are involved in the formation of the substrate-binding site. The presence of flexibility within these segments has been established from NMR relaxation parameters and measurements of amide proton exchange rates.

CONCLUSIONS

The solution structure of the serine protease PB92 presents a well defined global fold which is rigid with the exception of a restricted number of sites. Among the limited number of residues involved in significant internal mobility are those of two pockets, termed S1 and S4, within the substrate-binding site. The presence of flexibility within the binding site supports the proposed induced fit mechanism of substrate binding.

Surgical enucleation for renal cell carcinoma (RCC). Prognostic significance of tumour stage, grade and DNA ploidy

This study reviews a total of 26 renal cell carcinoma (RCC) who underwent enucleation of the tumour with functionally and anatomically normal controlateral kidney and no evidence of systemic renal disease. At follow-up, after a mean of 62 months the disease specific survival rate for this series was 88.5%. Survival rates according to the pathologic stage, grading, tumour diameter and ploidy are reported. Local recurrences were documented in 4 of the 26 RCC. All 4 RCC were more than 5 cm in diameter and recurred in the remaining parenchyma. After local recurrence, three tumours with aneuploid DNA content underwent radical nephrectomy, whereas 1 with diploid DNA content was submitted to a new enucleation of the recurrence. To date the diploid case is still alive 3 years after the original resection of the primary tumour whereas the other 3 patients died for metastatic disease. In our experience the ideal candidate for renal sparing surgery in the presence of a normal opposite kidney is an asymptomatic patient that incidentally is brought to our attention with a small size (less than 5 cm in diameter), low stage (T1-T2) tumour, well surrounded by a pseudocapsule. DNA content is a valuable prognostic factor in patients submitted to conservative surgery. Diploid tumours have been seen to have a better prognosis and in case of local recurrence they may be reconsidered for a new enucleation of the recurrence.

Alteration of cardiac function in patients with temporal lobe epilepsy: different roles of EEG-ECG monitoring and spectral analysis of RR variability

PURPOSE

Because several reports have described the relation between epilepsy and cardiac arrhythmias and suggest that changes in autonomic neural control of the heart could be involved in the pathogenesis of sudden unexplained death in patients with epilepsy, the aim of this study was to evaluate cardiac function in patients with temporal lobe epilepsy.

METHODS

Sixty-five patients with epilepsy were evaluated by simultaneous ambulatory 24-h EEG-ECG monitoring, and in 30 of these, power spectral analysis of relative-risk (RR) variability also was carried out, both in the supine position and in a passive tilt position at 60 degrees. The power spectrum of RR variability, the two major spectral components detectable at low frequency (LF) and at high frequency (HF), respectively, and the LF/HF ratio were calculated.

RESULTS

By EEG-ECG monitoring, we recorded six partial seizures, and in four cases, discharges were associated with sinus tachycardia. However, interictally the occurrence of ventricular and supraventricular arrhythmias was not different from that in normal subjects. The spectral analysis of RR variability, on the other hand, demonstrated in patients with epilepsy a significant decrease in the total RR variability and in both of its components (LF and HF) in the supine position, and of the LF/HF ratio in orthostatic position.

CONCLUSIONS

These findings suggest that the spectral analysis of RR variability may detect disorders of autonomic cardiac control in patients with epilepsy, even in the absence of abnormal findings during ECG monitoring. This alteration, which is more severe in cases with right EEG focus, could play a role in the pathogenesis of cardiac arrhythmias.

Multiple primary tumors: 17 cases of renal-cell carcinoma associated with primary tumors involving different steroid-hormone target tissues

The aim of this study was to analyze the characteristics of 17 women with renal-cell carcinoma (RCC) associated with other primary neoplasms occurring in steroid-hormone target tissues. The reproductive history of these patients and the use of exogenous hormones were taken into consideration. In all, 10 RCCs were associated with breast carcinoma; 4, with endometrial carcinoma; and 3, with ovarian carcinoma. The presentation of a second primary tumor was described as synchronous or metachronous by evaluation of the interval between the discovery of the two neoplasms. Hormone and surgical treatment as well as pathologic findings for each primary tumor were also reported. In these 17 RCCs the overall rate of disease-specific survival recorded after a mean follow-up period of 32.7 months (range 9-66 months) was 58.8%; 7 patients died of metastatic disease after surviving for a mean of 14.7 months. In terms of the pathologic stage of RCC, a significant difference in mean survival was found between pN0 (mean survival 22.1 +/- 3.4 months) and pN1 RCCs (mean survival 13.7 +/- 3.5 months). A total of 13 (76.4%) women were postmenopausal at the time of diagnosis of the first primary tumor; the mean age of these women at menopause was 51.7 +/- 1.2 years. No prior use of oral contraceptives was reported by 12 (70.5%) of the 17 patients. Plasma 17-beta-estradiol and estrone levels were determined in only 7 patients at the diagnosis of each of the primary tumors. High plasma estrogen levels were found in 4 women with RCC and breast carcinoma and in 1 patient with RCC and endometrial carcinoma; in the remaining 2 patients low-normal values were found. A relationship appears to exist between certain reproductive and hormone-related factors and the risk of developing these tumor associations. Data emerging from the present study do not provide strong support for the hypothesis of hormone dependency of RCC; however, a role for estrogens in cases in which RCC is associated with other primary tumors involving steroid-hormone target tissues can be hypothesized.