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Biomedical subjects

R Bolognesi

Publications and source records attributed to R Bolognesi.

At least 19 recordsLinked to original sources
PubMed2001

The peritrophic membrane of Spodoptera frugiperda: secretion of peritrophins and role in immobilization and recycling digestive enzymes.

A peritrophin from the Spodoptera frugiperda peritrophic membrane (PM) and microvillar proteins from S. frugiperda anterior midgut cells were isolated and used to raise antibodies in a rabbit. These antibodies, as well as a Tenebrio molitor amylase antibody that cross-reacts with S. frugiperda amylases, and wheat-germ aglutinin were used in immunolocalization experiments performed with the aid of confocal fluorescence and immunogold techniques. The results showed that the peritrophin was secreted by anterior midgut columnar cells in vesicles pinched-off the microvilli (microapocrine secretion). The resulting double membrane vesicles become single membrane vesicles by membrane fusion, releasing peritrophin and part of the amylase and trypsin. The remaining membranes still containing microvillar proteins and membrane-bound amylase and trypsin are incorporated into a jelly-like material associated with PM. Calcofluor-treated larvae lacking a PM were shown to lose the decreasing gradient of trypsin and chymotrypsin observed along the midgut of control larvae. This gradient is thought to be formed by a countercurrent flux of fluid (in the space between PM and midgut cells) that powers enzyme recycling.

Amylases↗
PubMed2001

Detection of early abnormalities of left ventricular function by hemodynamic, echo-tissue Doppler imaging, and mitral Doppler flow techniques in patients with coronary artery disease and normal ejection fraction.

We have investigated the possibility of detecting early abnormalities of left ventricular function at the initial phase of ischemic cardiomyopathy. Sixteen normotensive patients with coronary artery disease and normal left ventricular ejection fraction and 6 control patients were studied by invasive hemodynamic techniques in combination with transmitral Doppler flow or with echo-tissue Doppler imaging. The extent of the percentage of left ventricular longitudinal shortening and the systolic peak velocity at echo-tissue Doppler were significantly higher in the control patients than in patients with ischemic cardiomyopathy (P <.01). Left ventricular end-diastolic pressure was higher (P <.05), whereas mean values of isovolumic contraction and relaxation indexes (dP/dt/P: P <.05; +dP/dt: P <.05; -dP/dt: P <.01) were lower in patients with ischemic cardiomyopathy. Tau was significantly longer in ischemic patients (42.7 +/- 8.8 versus 34.5 +/- 3.7 ms, P <.05). In the control patients, the aortic valve closure to peak E interval by transmitral Doppler flow was significantly longer than that measured by echo-tissue Doppler (P <.001), whereas in patients with ischemic cardiomyopathy, this interval difference was still present and significantly shorter (P <.05). In patients with coronary artery disease and normal ejection fraction, minor and early abnormalities of left ventricular function related to isovolumic contraction and relaxation as well as to longitudinal shortening could be detected. In addition, a suction-like effect, detected during early filling evaluation with echo-tissue Doppler, is significantly decreased but not abolished during the early stages of coronary artery disease.

Adult↗
PubMed1998

Aortic intramural hematoma: an increasingly recognized aortic disease.

Aortic intramural hematoma (IMH) is a rarely diagnosed pathological condition that is not well characterized to date. We diagnosed IMH in 4 of 31 patients with suspected aortic dissection admitted to our coronary care unit from 1992 to 1995. In all 4 cases, IMH was located in the ascending aorta. At the time of hospitalization, all patients showed tachycardia, hypotension and pericardial effusion. Diagnosis of IMH was made by transesophageal echocardiography and computed tomography. We performed aortography in 2 patients, but it was non-diagnostic in both of them. One patient died before surgery. Autopsy confirmed the diagnosis of IMH and showed severe pericardial effusion. In another patient, the diagnosis was confirmed during successful surgery, while the remaining 2 patients recovered after medical therapy. The 3 surviving patients are still under follow-up control 12, 16 and 20 months after the initial acute event. We briefly discuss the epidemiological, clinical, diagnostic, therapeutic and prognostic aspects of IMH.

Aged↗
PubMed1998

[A rare case of massive pulmonary embolism and in transit cardiac thrombosis].

The case of a patient affected with acute pulmonary embolism and concomitant cerebral thromboembolism is described. The patient was admitted to our Coronary Care Unit with aphasia and hemiplegia. Five days before, he had undergone a hip replacement. A lung scan showed bilateral embolism; transthoracic echocardiogram revealed signs of pulmonary hypertension and the presence of a large, elongated, highly mobile "in-transit" thrombus entrapped into a patent foramen ovalis, and prolapsing into the right and left ventricle during diastole. The patient underwent surgical removal of the thrombus, with closure of the patent foramen. We did not treat the patient with thrombolysis, fearing the damage that a new embolism might produce. After surgery, the patient had a lengthy hospital stay because of renal failure and infection due to Pseudomonas aeruginosa. The patient was discharged from the hospital three months later on dialytic treatment and although he was still aphasic, there was partial recovery of motor function. Nevertheless, normalization of renal function and regression of aphasia occurred during the following months, with a residual mild motor defect of the right hand. This case report represents a starting point for discussing treatment of "in-transit" thrombi during pulmonary embolism.

Acute Kidney Injury↗
PubMed1997

Abnormal ventricular repolarization mimicking myocardial infarction after heterocyclic antidepressant overdose.

In 2 young adult women who experienced acute heterocyclic antidepressant intoxication, we found a quite unusual electrocardiographic pattern characterized by abnormal ST-tract elevation in the right precordial leads associated with a marked QRS widening (right bundle branch block and left anterior fascicular block type). Because serum electrolyte imbalance and acute myocardial ischemic events were excluded, the mechanism by which antidepressant overdose may produce such elevation of the ST tract remains unclear.

Adult↗
PubMed1996

Left-ventricular outflow tract obstruction by mitral valve ring calcification and proximal septal hypertrophy in elderly patients. Presentation of 2 clinical cases.

The pathophysiology, clinical presentation and prognosis of left-ventricular obstruction still represent an important cardiological problem. Various anatomical and/or functional mechanisms can cause this phenomenon. This report concerns 2 patients over 75 years old in whom the simultaneous presence of localized proximal septal hypertrophy and massive calcification in the anterior portion of the mitral valve ring provoked significant systolic intraventricular gradients. Cardiac rhythm disturbances and consequent variability of R-R intervals, found in both subjects, appear fundamental in determining the value of such gradients. Occasionally an anterior mitral ring calcification may bring about left-ventricular outflow tract obstruction in aged hearts where localized hypertrophy of the proximal portion of the intraventricular septum is present.

Aged↗
PubMed1996

Clinical, electrocardiographic, and echocardiographic features in patients with asymptomatic aortic abdominal aneurysm.

Cardiac involvement in peripheral vascular diseases can present interesting patho-physiological aspects and can influence the prognosis. The authors evaluated the cardiac condition of patients with asymptomatic aortic abdominal aneurysm (AAAA) by using clinical, electrocardiographic, and echocardiographic techniques. Seventy-eight patients were studied, 74 men and 4 women, with ages ranging from fifty-five to eighty-one years (mean 69.5 +/- 6.4). All patients were submitted to a complete clinical examination, usual blood tests, a 12-lead resting electrocardiogram, and an echo-Doppler evaluation. Forty-eight subjects (61.5%) were affected by hypertension, 53 (67.9%) were smokers, 25 (32.1%) were alcohol abusers, 39 (50%) had a history of angina pectoris, 20 (25.6%) had had previous myocardial infarction, and 30 (38.5%) were receiving active cardiovascular treatment. All patients except 2, who had chronic atrial fibrillation, manifested sinus rhythm. Electrocardiographic signs of left ventricular (LV) hypertrophy were present in 20 cases (25.6%), intraventricular conduction disturbances in 19 (24.4%), pathological Q waves in 20 (25.6%), and primary repolarization abnormalities in 25 (32.1%). Echocardiography showed a slight increase in left atrial diameter and intraventricular septum thickness (41.5 +/- 4.3 and 12.3 +/- 2 mm respectively). A clearer increase was found in LV mass index (159 +/- 44 g/m2). In 31 patients one or more LV asynergic segments were found. In our patients with AAAA the prevalence of major risk factors for atherosclerosis and ischemic heart disease including previous myocardial infarction was high. Echo-derived LV myocardial mass index was higher than normal even though electrocardiographic criteria for LV hypertrophy did not match echocardiographic data in all subjects. Finally a moderate prevalence of intraventricular conduction disturbances was recorded.

Aged↗
PubMed1995

Left ventricular false aneurysm: an unusually prolonged natural history.

A case of left ventricular false aneurysm of postinfarctual etiology with an unusually prolonged natural history (12 years survival) is reported. A first diagnosis of this rare cardiac complication was made in 1982 on the basis of hemodynamic and echocardiographic results. At that time the patient rejected surgical therapy. Eleven years later the patient came back to our attention after resuscitation from a sudden cardiac death. Hemodynamic and echocardiographic (transesophageal) tests showed a remarkable impairment of left ventricular function and an abnormal enlargement (10 x 8 cm) of a pseudoaneurysmatic cavity full of thrombi. The patient died suddenly in April 1994. We emphasize the unusual, prolonged survival of our patient suffering from an unresected left ventricular false aneurysm of postinfarctual etiology.

Aged↗
PubMed1995

Effect of aging on left ventricular filling in untreated hypertensive patients.

The aim of this study was to evaluate the influence of age and other clinical and echocardiographic parameters on left ventricular filling in a group of 174 untreated patients with mild to moderate hypertension (aged 20-82 years; mean 51.2 years) and in 189 age-matched normotensive subjects. All subjects underwent an echocardiographic study with pulsed Doppler evaluation of left ventricular filling. Left ventricular dimensions and indexes of systolic function were similar and within normal limits in both groups. Left ventricular filling was altered in hypertensive subjects < 65 years with a decrease of peak early velocity (peak E), an increase of peak atrial velocity (peak A) and a reduced E/A ratio. However in subjects > or = 65 years, we did not observe any differences in transmitral flow velocity pattern between hypertensive and normotensive subjects. The stepwise regression analysis showed that age alone explains up to 8% of peak E variance, 14% of peak A and 26% of E/A ratio in hypertensives, while in normotensives it explains up to 18% of peak E variance, 50% of peak A and 61% of E/A ratio. The other variables entered into the regression slightly improved the predictive power. In conclusion, age is the major independent factor affecting left ventricular filling in both groups, even if its predictive power was smaller in the hypertensive group. The similarity of diastolic filling pattern in elderly hypertensive and normotensive subjects suggests that the 'aging factor' plays an important role in influencing left ventricular filling pattern so as to mask the effect of hypertension in the elderly patients.

Adult↗
PubMed1994

Skin contamination and low airborne nickel exposure of electroplaters.

The present study was performed to evaluate the role of hand and facial contamination in the absorption of soluble nickel compounds in 41 male subjects employed in electroplating operations in 25 small factories in the province of Florence (Italy). Personal exposure to airborne nickel ranged from 0.10 to 42 micrograms/m3; the median (range) urine, hands and face nickel levels were 4.2 (0.7-50) micrograms/l, 39 (1.9-547) micrograms, 9.0 (1.0-86) micrograms, respectively. Face nickel values explained the bulk of the variance in urine nickel levels (42%). In stepwise multiple regression analysis all other variables were not significant. The log-linear model can be expressed as: log (urine-Ni) = 0.295 + 0.593 log (face-Ni). Our results suggest that skin contamination, especially facial skin, plays an important role in nickel absorption in exposed workers.

Absorption↗
PubMed1994

How do calcium antagonists differ in clinical practice?

The majority of calcium antagonists used clinically belong to three distinct chemical classes: the phenylalkylamines, the dihydropyridines, and the benzothiazepines. In recent years their mode of action has been unravelled, their limitations recognized, and their efficacy and use in the management of patients with a broad spectrum of cardiovascular and other disorders defined. It is clear, however, that these drugs are not all alike, providing an explanation for their differing effects. The final therapeutic effect in humans depends on the mechanisms of action at the molecular level, the tissue selectivity, and the hemodynamic changes of each agent. All these aspects are examined in detail in this article. Concepts that are highlighted are as follows: (a) Molecular biology has allowed recognition of the polypeptide components of the alpha 1 subunit of the L-type Ca2+ channel and the finding of peptide segments covalently labelled by all three classes of drugs. (b) The location of these segments within the peptides is different: Binding sites for dihydropyridines are located externally, whereas those for verapamil and diltiazem are located internally, in the cytosolic part of the membrane. (c) Dihydropyridine binding is voltage dependent. This explains the selectivity of this class of drugs for vascular smooth muscle, which is more depolarized than cardiac muscle. (d) Phenylalkylamines and benzothiazepines reach their receptors at the internal surface of the sarcolemma through the channel lumen. Their binding is facilitated by the repetitive depolarization of atrioventricular and cardiac tissue, a phenomenon described as use dependence. This explains why these drugs are not highly selective, but equipotent for the myocardium, the atrioventricular conducting tissue, and the vasculature. (e) Dihydropyridines act through selective vasodilatation and may increase heart rate and contractility via a reflex mechanism. On the contrary, phenylalkylamines and diltiazem act through a combination of effects, including reduction of afterload, heart rate, and contractility. When taken together, all these differences distinguish the preferential clinical utilization of one of these compounds for a given cardiovascular pathology.

Binding Sites↗
PubMed1994

Do inotropic drugs always induce a positive lusitropic effect? A comparison between k-strophanthidin and dobutamine in patients with coronary artery disease.

The interaction between systolic and diastolic effects of inotropic drugs is an important subject which has not yet been fully clarified in the cardiological literature. The effects of the inotropic drugs k-strophanthidin and dobutamine on left ventricular (LV) relaxation and early filling phase were compared in patients with coronary artery disease (CAD) and preserved systolic function. Twenty-two patients were randomly divided into two groups; group I was infused with 0.0035 mg.kg-1 of k-strophanthidin for 10 min and group II with dobutamine at a rate of 10 micrograms.kg-1.min-1 for 10 min. Both groups underwent simultaneous haemodynamic and echo 2D-Doppler evaluations at controlled heart rate. K-strophanthidin improved contractility indexes (peak of LV systolic pressure P < 0.001, max dP/dt + P < 0.05 and dP/dt P < 0.01) and worsened T constant and LV lowest diastolic pressure, (LVLDP) (P < 0.001 and P < 0.05 respectively) without changing early transmitral filling parameters. Dobutamine induced a significant increase in contractility in group II but at the same time significantly improved LV relaxation variables (max dP/dt - P < 0.01 and T constant P < 0.001). In addition, dobutamine reduced LVLDP (P < 0.05) and significantly increased LV early filling parameters. These results show that an acute administration of either k-strophanthidin or dobutamine enhances contractility, whereas these drugs have the opposite effect on the early diastolic phase.

Age Factors↗
PubMed1994

Single coronary artery-right ventricular fistula with a partially thrombosed large aneurysm of its proximal tract in a 66-year-old man.

An exceptional combination of three major coronary anomalies: a single coronary artery, a congenital coronary-right ventricular fistula and a large proximal coronary aneurysm were found in a living 66-year-old patient suffering from post-myocardial ischaemic heart disease. Each coronary anomally and their influence on the clinical situation of the patient are briefly discussed.

Aged↗