Alpine Viticulture and Climate Change: Environmental Resources and Limitations for Grapevine Ripening in Valtellina, Italy

The effects of the spatial and temporal variability of environmental factors on viticulture are particularly important in mountainous wine regions due to their complex geomorphology. A typical example is Valtellina, an Italian valley in the middle of the Alpine chain known for its wine production. The aim of this work was to assess the effects of the current climatic conditions on Alpine viticultural production by evaluating the relationship between sugar accumulation, acid degradation, and environmental factors. To achieve this objective, a 21-year time series of ripening curves from 15 vineyards (cv Nebbiolo) along the Valtellina wine-growing belt was collected. The ripening curves were then analysed in conjunction with meteorological data to assess the influence of geographical and climatic characteristics, as well as other limiting environmental factors, on grape ripening. Valtellina is currently characterised by a stable warm phase, with yearly precipitation slightly higher than in the past. In this context, the timing of ripening and the level of total acidity are correlated with altitude, temperature, and summer thermal excess. Precipitation shows good correlations with all the maturity indices, so higher precipitation leads to late ripening and higher total acidity. Considering the oenological goal of local wineries, the results suggest that the Alpine area of Valtellina is currently facing favourable environmental conditions, with early development and increased levels of sugar while maintaining good levels of acidity.

Myocardial injury in patients hospitalized for SARS-CoV19: a maker or a marker of prognosis?

Background

Since the beginning of the coronavirus disease 2019 (COVID-19) pandemic, literature data are progressively accumulating, attesting to the possible prognostic role of cardiac troponins in patients who need hospitalization because of COVID-19 infection.

Purpose

To assess whether myocardial injury (measured by high sensitivity troponins) is an independent cause of disease severity and prognosis.

Methods

We performed a patient-level metanalysis (PROSPERO ID: CRD42020213209) in unselected patients hospitalized because of COVID-19 infection in whom the severity of respiratory failure was also evaluated at admission. To allow for comparison, troponin values were normalized to their threshold levels to obtain a normalized troponin (nTn) value which was used as a continuous variable in all analysis.

Results

A total of 722 patients were included in the analysis. Of note, patients who had elevated troponins at hospital admission had a significantly lower oxygenation status than those with normal nTn (PaO2/FiO2 232±215 vs. 276±124 mmHg/%; p<0.001). On the contrary, those with cardiovascular comorbidities had similar PaO2/FiO2 but higher nTn than those without (5.6817 vs. 2.1110 ng/mL; p=0.002).

After a median follow-up of 14 days, 180 deaths were observed. At multivariable regression analysis, age, male sex, moderate-severe renal dysfunction (eGFR <30 mL/min/m2) and lower PaO2/FiO2, were independent predictor of death (igure 1). The restricted cubic spline curves in Figure 2A and 2B show the hazard ratios (HRs) and 95% confidence interval for death according to nTn and PaO2/FiO2 levels as continuous variables. A linear increase in the HR is observed with lower PaO2/FiO2 values below the normal value of 300. On the contrary, the nTn spline curve is near-flat with large confidence interval for values above the normality thresholds.

Conclusion

In patients hospitalized for COVID-19, mortality is mainly driven by gender, age and respiratory failure while myocardial damage is not an independent predictor of worse survival when respiratory function is accounted for.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

Supporting the improvement of air quality management practices: The "FAIRMODE pilot" activity

This paper presents the first outcomes of the "FAIRMODE pilot" activity, aiming at improving the way in which air quality models are used in the frame of the European "Air Quality Directive". Member States may use modelling, combined with measurements, to "assess" current levels of air quality and estimate future air quality under different scenarios. In case of current and potential exceedances of the Directive limit values, it is also requested that they "plan" and implement emission reductions measures to avoid future exceedances. In both "assessment" and "planning", air quality models can and should be used; but to do so, the used modelling chain has to be fit-for-purpose and properly checked and verified. FAIRMODE has developed in the recent years a suite of methodologies and tools to check if emission inventories, model performance, source apportionment techniques and planning activities are fit-for-purpose. Within the "FAIRMODE pilot", these tools are used and tested by regional/local authorities, with the two-fold objective of improving management practices at regional/local scale, and providing valuable feedback to the FAIRMODE community. Results and lessons learnt from this activity are presented in this paper, as a showcase that can potentially benefit other authorities in charge of air quality assessment and planning.

Hemorrhagic symptoms and bleeding risk in obligatory carriers of type 3 von Willebrand disease: an international, multicenter study

OBJECTIVES

We undertook an international, multicenter study to describe the clinical picture and to estimate the bleeding risk in a group of obligatory carriers of type 3 von Willebrand disease (VWD).

PATIENTS AND METHODS

Obligatory carriers (OC) of type 3 VWD were identified by the presence of offspring with type 3 VWD or by being an offspring of a type 3 patient. Normal controls were age- and sex-matched with the obligatory carriers. A physician-administered standardized questionnaire was used to evaluate hemorrhagic symptoms at presentation. A score system ranging from 0 (no symptom) to 3 (hospitalization, replacement therapy, blood transfusion) was used to quantitate bleeding manifestations. Odds ratios were computed for each symptom.

RESULTS

Ten centers participated to the study, enrolling a total of 35 type 3 VWD families, with 70 OC. A total of 215 normal controls and 42 OC for type 1 VWD were also included. About 40% of type 3 OC had at least one bleeding symptom compared to 23% of normal controls and 81.8% of type 1 OC (P < 0.0001 by chi-squared test), showing that type 3 OC clearly represent a distinct population from type 1 OC. The clinical situations associated with an increase of bleeding risk in type 3 OC were epistaxis [odds ratio 3.6; 90% confidence intervals (CI) 1.84-21.5], cutaneous bleeding (odds ratio 5.5; 90% CI 2.5-14.1) and postsurgical bleeding (odds ratio 16.3; 90% CI 4.5-59). The severity of bleeding score correlated with the degree of factor (F) VIII reduction in plasma.

CONCLUSIONS

OC for type 3 VWD represent a distinctive population from type 1 OC. These patients, however, present with more frequent bleeding symptoms in comparison to normal controls, especially in case of significantly low FVIII. Desmopressin and/or tranexamic acid might be useful to prevent or treat bleeding in these cases.

The discriminant power of bleeding history for the diagnosis of type 1 von Willebrand disease: an international, multicenter study

OBJECTIVE

The aim of this study was the validation of the criteria defining a significant mucocutaneous-bleeding history in type 1 von Willebrand disease (VWD).

SUBJECTS AND METHODS

To avoid selection bias, 42 obligatory carriers (OC) of type 1 VWD were identified from a panel of 42 families with type 1 VWD enrolled by 10 expert centers. OC were identified by the presence of an offspring and another first degree relative with type 1 VWD (affected subjects, AFF). A standardized questionnaire was administered to evaluate hemorrhagic symptoms at the time of first examination, using a bleeding score ranging from 0 (no symptom) to 3 (hospitalization, replacement therapy, blood transfusion). Sensitivity, specificity, diagnostic likelihood ratios, positive and negative predictive values for the diagnosis of type 1 VWD were calculated from the data collected in OC and in 215 controls.

RESULTS

Having at least three hemorrhagic symptoms or a bleeding score of 3 in males and 5 in females was very specific (98.6%) for the bleeding history of type 1 VWD, although less sensitive (69.1%). None of the misclassified OC had life-threatening bleeding episodes after diagnosis.

CONCLUSIONS

We suggest that the use of a standardized questionnaire and bleeding score may be useful for the identification of subjects requiring laboratory evaluation for VWD.

Evaluation of drainage times and alarms with various automated peritoneal dialysis modalities

This paper assesses the variation in total drainage time (TDT) and number of alarms due to low drainage volume (LDV) in automated peritoneal dialysis (APD) patients with varying catheter performance. Catheter performance was measured by drainage break point (DBP) in a supine position. Six patients with DBP > or = 80% underwent three types of APD: non tidal, 50% tidal, and 80% tidal. Six patients with DBP < 70% underwent two types of APD: non tidal and tidal fixed at 5% below DBP. In every case, the fill volume was 2.3 L. For the purpose of the study, each treatment was continued for seven consecutive nights. Home Choice Pro (Baxter Healthcare Corporation, Deerfield, Illinois, U.S.A.) was used to calculate the TDT and LDV. With both the non tidal and tidal treatments, TDT was higher in patients with DBP < 70% as compared with patients with DBP > or = 80%. In the latter group, 50% tidal was the most effective technique in reducing TDT. In patients with DBP < 70%, the tidal treatment reduced not only TDT, but also LDV alarms, as compared to the non tidal treatment. In conclusion, choosing the tidal method helps to reduce LDV alarms and TDT, especially in patients with a low DBP. The Home Choice Pro device is an effective aid in setting up and assessing the dialytic prescription.

Ultrafiltration with icodextrins in continuous ambulatory peritoneal dialysis and automated peritoneal dialysis

Icodextrins (Icos) produce constant linear ultrafiltration (UF). This effect allows Icos to replace glucose during long dwells in continuous ambulatory peritoneal dialysis [CAPD (nighttime)] and automated peritoneal dialysis [APD (daytime)]. However, the effectiveness of Icos in producing UF (IcoUF) is limited by lymphatic reabsorption, whose extent depends partly on posture and physical activity. This paper aims to assess whether the difference in posture and physical activity between daytime dwells in APD and nighttime dwells in CAPD affects IcoUF. Patients undergoing first treatment were retrospectively examined. Ten patients were on CAPD [4 males, 6 females; average age, 73.0 +/- 13.4 years; body surface area (BSA), 1.63 +/- 0.21 m2; total volume per day, 5.6 +/- 1.9 L], and ten were on APD (7 males, 3 females; average age, 67.7 +/- 9.8; BSA, 1.75 +/- 0.22 m2; total volume per night, 10.5 +/- 0.9 L). Ultrafiltration was assessed for seven consecutive days preceding a peritoneal equilibration test (PET) and collection of diuresis. In both groups, 3 patients had no diuresis, and the difference between CAPD and APD was not significant (625 +/- 762 mL vs 780 +/- 878 mL). Moreover, no significant difference was seen in 4-hour dialysate-to-plasma creatinine (D/P) between CAPD (0.65 +/- 0.12) and APD (0.64 +/- 0.05). Dwell times with Icos were shorter in CAPD than in APD (11.5 +/- 1.8 hours vs 14.8 +/- 0.5 hours, p < 0.0005), but the fill volume was not significantly different (1760 +/- 286 mL vs 1790 +/- 249 mL). Water excretion owing to diuresis and dialysis [total water excretion (TWE): 1619 +/- 497 mL CAPD vs 1762 +/- 736 mL APD] and dialytic UF (363 +/- 443 mL CAPD vs 748 +/- 479 mL APD), which is not linked to Icos, were not significantly different between the two groups. The IcoUF and the percentage of IcoUF to TWE were significantly higher in CAPD compared to APD [631 +/- 253 mL (44% +/- 27%) vs 234 +/- 215 mL (19% +/- 19%), p < 0.001 (p < 0.05)]. In conclusion, an upright posture and physical activity seem to produce less IcoUF in APD despite the longer dwell. These factors could, indeed, produce greater intraperitoneal pressure, resulting in increased lymphatic reabsorption during a daytime dwell.

Enoximone echocardiography for predicting recovery of left ventricular dysfunction after revascularization : a novel test for detecting myocardial viability

BACKGROUND

The possibility that enoximone, a nonglycoside, noncatechol, positive inotropic agent, in combination with 2-dimensional echocardiography may predict recovery of myocardial dysfunction after revascularization has not been yet evaluated.

METHODS AND RESULTS

Forty-five patients with chronic coronary artery disease and left ventricular dysfunction underwent dobutamine (DE, 5 to 10 microg. kg(-1). min(-1)) and enoximone (EE, 1.5 mg/kg, over 10 minutes) echocardiography. Myocardial wall motion was scored from 1 (normal) to 4 (dyskinesia): an asynergic segment was considered to have contractile enhancement when the score decreased by >/=1 grade. Of 478 asynergic segments, 216 (45%) exhibited functional recovery after revascularization. Dobutamine- and enoximone-induced contractile enhancement was observed in 41% and 46% of segments, respectively. Compared with DE, EE had higher sensitivity (88% versus 79%, P<0.01) and negative predictive value (90% versus 84%, P<0.05) in predicting functional recovery. The specificity (89% versus 90%) and positive predictive value (87% for both EE and DE) were similar. Concordant interpretation of EE and DE findings was found in 85% (406 of 478) of affected segments. Prerevascularization coronary angiography showed that stenosis severity of vessels supplying areas which only improved with enoximone was significantly greater (89.9%) than that of vessels (77.7%) supplying areas that responded to both agents (P<0.02). Both dobutamine and enoximone increased heart rate (16% and 10%, respectively), whereas enoximone did not cause changes in systolic blood pressure that increased by 14% with dobutamine.

CONCLUSIONS

Enoximone echocardiography provides a novel and reliable approach for the prediction of functional recovery after revascularization. Compared with dobutamine echocardiography, the test yields higher sensitivity and induces lesser hemodynamic alterations.

Short- and long-term evolution of unstented nonocclusive coronary dissection after coronary angioplasty

OBJECTIVES

We assessed the short- and long-term clinical and angiographic outcome of nonocclusive unstented dissection after percutaneous transluminal coronary angioplasty (PTCA) and its correlation with restenosis.

BACKGROUND

The use of stents has dramatically increased both the number and the cost of coronary revascularization procedures. However, this technique is not completely risk free, and its benefits have not been fully demonstrated in uncomplicated dissections.

METHODS

We studied 129 consecutive patients with 49 nonocclusive dissections after PTCA (grades A to D of National Heart, Lung, and Blood Institute classification) and good distal flow (TIMI [Thrombolysis in Myocardial Infarction] flow grade 3). All patients underwent coronary angiography at 24 h and at six months post-PTCA. Clinical status was assessed every three months in the outpatient clinic. Study subjects were matched with 60 other patients in whom stenting was performed for the presence of dissection.

RESULTS

In the former group, all but two patients (with type E dissection, which evolved to coronary occlusion and myocardial infarction) improved their dissection score during follow-up: at six months only 18 dissections were still angiographically visible, and no clinical adverse events were recorded. In the dissected vessels, the restenosis rate was significantly lower than in those without dissection (12% vs. 44%, p < 0.001); in the stented vessels, the restenosis rate was 25% (15/60).

CONCLUSIONS

In the presence of TIMI flow grade 3, coronary dissection is associated with a favorable outcome and predicts a low restenosis rate. These results caution against the indiscriminate use of intravascular prostheses in the event of nonocclusive coronary dissection.

[Cardiac tamponade after coronary angioplasty induced by treatment with ReoPro]

We report a complication observed in a 77-year-old man admitted to another hospital for "de novo" angina, in which coronary angiography showed a proximal 65% stenosis of the left anterior descending artery. The patient was medically stabilized, but one month later he developed unstable angina that was not controlled by heparin, nitrate and calcium antagonist infusions. Therefore, he was started on ReoPro (0.25 mg/kg bolus and 10 micrograms/min infusion) but because of persisting symptoms, he was transferred to our unit for urgent PTCA. Angioplasty plus stenting was successful and angina disappeared. The ReoPro infusion was stopped (6 hours after it had been started) for mild oral bleeding. Blood analysis was normal (including platelet count) except for the activated partial thromboplastin (PTT) and prothrombin (PT) time, which exceeded the laboratory limits of determination. Consequently, heparin infusion was also stopped. Eight hours after PTCA, he suddenly developed hypotension, bradycardia and loss of consciousness. The echocardiogram revealed a large pericardial effusion with diastolic collapse of the right cardiac chambers. The patient was treated with volume expanders, plasma and platelet units in an attempt to reestablish a normal hemodynamic pattern and normal platelet function. Elective pericardiocentesis was performed 24 hour later, with drainage of 800 ml of hematic effusion. Severe hemorrhagic complication was induced by ReoPro despite a normal platelet count. This was successfully counteracted with plasma and platelet infusion.

[Role of stress myocardial perfusion scintigraphy in the follow-up of patients undergoing coronary angioplasty: comparison between qualitative and semi-quantitative analysis]

In order to assess the diagnostic accuracy of stress/rest myocardial perfusion scintigraphy in the follow-up of patients undergoing percutaneous transluminal coronary angioplasty (PTCA) we studied 50 patients (pts) before and 6 months after PTCA. All patients underwent control coronary angiography and then were divided in 2 groups, according to angiographic evidence of restenosis (25 pts) or no restenosis (25 pts). Myocardial perfusion imaging was performed with 99mTc-methoxy-isobutyl-isonitrile (MIBI). For MIBI scans, both qualitative and semi-quantitative analysis were performed. SPECT images were displayed on a color monitor in random order and graded blindly by 2 experienced observers. Rest and stress MIBI uptake was scored using a 4-point scale (ranging from 0 = normal, to 3 = absence of uptake). Individual subjects' perfusion scores were calculated by adding the individual segments' scores. History of relapsing angina showed a sensitivity and specificity of 76 and 96%, respectively. Exercise testing and MIBI tomoscintigraphy exhibited sensitivity and specificity of 80 and 56%, and 92 and 44%, respectively. However, when considering semiquantitative data and comparing them with pre-PTCA studies, specificity of MIBI scan increased to 96%, while sensitivity decreased to 72%. The results of the present study confirm high sensitivity and low specificity for both exercise ECG and myocardial perfusion scintigraphy, in the detection of restenosis following PTCA. However, when performing semiquantitative analysis of perfusion scanning and comparison with pre-PTCA images, the specificity of MIBI tomoscintigraphy increases significantly. Therefore, when adopting myocardial perfusion scintigraphy for the follow-up of patients undergoing PTCA, a pre-revascularization scan should be obtained as often as possible. This approach, in the context of a positive test, makes feasible the assessment of often partial improvements in perfusion of the myocardium relative to the treated vessel, consequently avoiding many false positive results which invariably lead to coronary angiography.

Coronary recanalization by elective angioplasty prevents ventricular dilation after anterior myocardial infarction

OBJECTIVES

In a prospective study we evaluated whether late recanalization of the left anterior descending coronary artery (LAD) affects ventricular volume and function after anterior myocardial infarction.

BACKGROUND

Persistent coronary occlusion after anterior myocardial infarction leads to ventricular dilation and heart failure.

METHODS

We studied 73 consecutive patients with acute anterior myocardial infarction as a first cardiac event; all had an isolated lesion or occlusion of the proximal LAD. Six patients died before hospital discharge. The 67 survivors were classified into two groups: group I (patent LAD and good distal flow, n = 40) and group II (LAD occlusion or subocclusion, n = 27). The 20 patients in group I who had significant residual stenosis and all patients in group II underwent elective percutaneous transluminal coronary angioplasty (PTCA) within 18 days of myocardial infarction. The procedure was successful in 17 patients in group I (group IB) and in 16 patients in group II (group IIA): in the remaining 11 patients of group II, patency could not be reestablished (group IIB). Left ventricular volumes, ejection fraction and a dysfunction score were measured by echocardiography on admission, before PTCA, at discharge and after 3 and 6 months.

RESULTS

Although cumulative ST segment elevation was similar in groups I and II, ejection fraction and dysfunction score were significantly worse in group II. However, ventricular function and volumes progressively improved in group IIA, whereas group IIB exhibited progressive deterioration of function (dysfunction score [mean +/- SD] increased from 21 +/- 6 to 25 +/- 8, p < 0.05; ejection fraction decreased from 43 +/- 10% to 37 +/- 11%, p < 0.05); and end-systolic volume increased from 34 +/- 10 to 72 +/- 28 ml/m2, p < 0.05). Patients in group IIB also had worse effort tolerance, higher heart rate at rest, lower blood pressure and significantly greater prevalence of chronic heart failure.

CONCLUSIONS

Delayed PTCA of an occluded LAD can frequently restore vessel patency. Success appears to be associated with better ventricular function and a lack of chronic dilation. Large randomized studies are warranted to evaluate the effect of delayed PTCA on late mortality.

Specificity and sensitivity of exercise-induced ST segment elevation for detection of residual viability: comparison with fluorodeoxyglucose and positron emission tomography

OBJECTIVES

We evaluated the sensitivity and specificity of exercise-induced ST segment elevation for the detection of residual myocardial viability.

BACKGROUND

Assessment of residual viability after myocardial infarction is relevant for establishing indication for revascularization. We have previously shown that exercise-induced ST segment elevation is a marker of residual viability.

METHODS

We studied 34 patients with a previous Q wave myocardial infarction (anterior in 21, inferior in 13) of whom 18 (group A) had exercise-induced ST segment elevation in more than one lead (mean [+/- SD] 1.8 +/- 0.9 mm, range 1 to 4) and 16 (group B) did not. All patients underwent rest technetium-99m methoxyisobutyl isonitrile single-photon emission computed tomography (SPECT), fluorine-18 (F-18) fluorodeoxyglucose positron emission tomography and coronary angiography. The time elapsed between the infarction and the viability study was 72 +/- 108 days (range 15 to 400) in group A and 516 +/- 545 days (range 14 to 1,800) in group B.

RESULTS

The presence and site of previous infarction were confirmed by SPECT studies in all 34 patients. Uptake of F-18 fluorodeoxyglucose within the infarcted area was present in 18 of 18 patients in group A but in only 9 (56%) of 16 in group B (p < 0.01). In patients with an anterior infarction, the sensitivity, specificity and predictive accuracy of exercise-induced ST segment elevation for detection of residual viability were 82%, 100% and 86%, respectively (95% confidence intervals 46% to 83.5%, 59% to 100% and 55.6% to 87.1%, respectively).

CONCLUSIONS

Exercise-induced ST segment elevation in infarct-related leads has a high specificity and acceptable sensitivity for detection of residual viability within the infarcted area.

99Tcm-MIBI single photon emission tomography (SPET) for detecting myocardial ischaemia and necrosis in patients with significant coronary artery disease

The ability of 99Tcm-methoxyisobutylisonitrile (MIBI) single photon emission tomography (SPET) to detect myocardial ischaemia and necrosis was assessed in 56 patients (45 male, 11 female, aged 55 +/- 5 years), with clinically recognized ischaemic heart disease (IHD). All underwent coronary angiography (CA) and left ventriculography (LV). SPET images were obtained at rest and at peak exercise (Modified Bruce) 90 min after injection of 99Tcm-MIBI (650-850 MBq). Data were acquired in 30 min over 180 degrees (from 45 degrees RAO to 45 degrees LPO) with no correction for attenuation, using a 64 x 64 matrix. The presence of persistent (P) or reversible (R) perfusion defects (PD) was then correlated to the resting and exercise ECG and to the results of CA and LV. Of the 56 patients, 34 had reversible underperfusion (RPD), 46 persistent underperfusion (PPD) and 31 had both. The occurrence of RPD correlated well with the occurrence of exercise-induced ST segment depression and/or angina (27 patients of 34 patients, 79%) and with the presence of significant coronary artery disease (CAD) (33 of 44, 73%). In 45 of 46 patients (98%) PPD corresponded to akinetic or severely hypokinetic segments (LV) usually explored by ECG leads exhibiting diagnostic Q waves (42 of 46 patients, 91%). The scan was normal both at rest and after stress in four of 11 patients with no CAD, and in two of 45 patients with CAD. Finally, an abnormal resting scan was seen in seven of 11 patients with normal coronary arteries, of whom six had regional wall motion abnormalities.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary collaterals reduce the duration of exercise-induced ischemia by allowing a faster recovery

The role of collaterals in influencing postischemic recovery after exercise testing has not been investigated previously. We studied 54 patients (mean age 59 +/- 6 years) with effort-induced angina and documented coronary disease who underwent exercise testing and thallium-201 myocardial scintigraphy. On angiography, 30 patients (group A) exhibited visible collaterals (grade 2 to 3, Cohen and Rentrop classification) perfusing the ischemic zone, whereas the other 24 (group B) did not. Patients with collaterals had more severe coronary artery disease (Gensini score 46.9 +/- 16 vs 28.6 +/- 18; p less than 0.001) and more severe impairment of coronary flow reserve (time and rate-pressure product to 1 mm ST segment depression 3.5 +/- 0.8 vs 4.8 +/- 0.6 minutes, p less than 0.01; 14,189 +/- 2451 vs 16,081 +/- 2215 beats/min x mm Hg, p less than 0.04, respectively). However, in these patients the ECG returned to baseline more rapidly after exercise (5.5 +/- 1.6 vs 11.7 +/- 3.3 minutes; p less than 0.001). Therefore, although collaterals do not apparently prevent or delay the development of exercise-induced ischemia, they can limit its duration by allowing a faster recovery.

Assessment of residual tissue viability by exercise testing in recent myocardial infarction: comparison of the electrocardiogram and myocardial perfusion scintigraphy

The assessment of residual myocardial viability in infarcted areas is relevant for subsequent management and prognosis but requires expensive technology. To evaluate the possibility that simple, easily obtainable clinical markers may detect the presence of within-infarct viable tissue, the significance of exercise-induced ST elevation occurring in leads exploring the area of a recent Q wave myocardial infarction was assessed. Twenty-five patients with recent (less than 6 months) myocardial infarction were studied. All had angiographically documented coronary artery disease, diagnostic Q waves (n = 24) or negative T waves (n = 25) on the rest 12-lead electrocardiogram and exhibited during exercise greater than or equal to 1.5 mm ST segment elevation (n = 17) or isolated T wave pseudonormalization (n = 8) in the infarct-related leads. ST-T wave changes were reproduced in all patients during thallium-201 exercise myocardial scintigraphy. A fixed perfusion defect was observed in 24 of the 25 patients. A reversible defect was seen in 16 (94%) of 17 patients who exhibited transient ST elevation during exercise but in only 4 (50%) of the 8 patients who had only T wave pseudonormalization. In conclusion, in patients with recent myocardial infarction, analysis of simple ST segment variables obtained during exercise testing may allow a first-line discrimination of those who may potentially benefit from a revascularization procedure.

[Coronary angioplasty in the presence of a myocardial bridge: a clinical case]

Percutaneous transluminal coronary angioplasty (PTCA) is a widely used technique of myocardial revascularization. The number of patients treated by PTCA is continuously growing in spite of its major drawback, represented by restenosis in approximately 30% of patients. We report here the case of a PTCA performed on a tight left anterior descending lesion in the presence of a muscular bridge involving the stenotic area. The procedure was completely successful by both the angiographic and clinical side. Good patency of the vessel with nearly complete disappearance of the lesion was confirmed at 6-month angiographic follow-up. In conclusion, the presence of a muscular bridge involving the stenotic area does not seem to represent a contraindication to PTCA.

Interaction of ferredoxin and ferredoxin-NADP reductase with thylakoids

Ferredoxin-NADP reductase accounts for about 50% of the NADPH diaphorase activity of spinach leaf homogenates. The enzyme is bound to thylakoid membranes, but can be slowly extracted by aqueous buffers. Ferredoxin-NADP reductase can be extracted from the membranes by a 1- to 2-min treatment with a low concentration of trypsin. This treatment completely inactivates NADP photoreduction but does not affect electron transport from water to ferredoxin. It is shown that the inactivation is due to solubilization of ferredoxin-NADP reductase: the activity can be restored by addition of a very large excess of soluble enzyme in pure form. When ferredoxin-NADP reductase is added as a soluble enzyme after extraction or inactivation (by a specific antibody) of the membrane-bound enzyme, NADP photoreduction requires a very large excess of this enzyme, and the apparent Km for ferredoxin is also increased. These observations are discussed as related to the interactions of thylakoids with ferredoxin-NADP reductase.