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Biomedical subjects

M Rossi

Publications and source records attributed to M Rossi.

At least 343 records · Page 19Linked to original sources

Basement membrane thickening in small intramyocardial vessels in eosinophilic myocarditis.

The case reported in this paper, besides illustrating several aspects of the eosinophilic myocarditis, documents a yet undescribed feature of the cardiac involvement in idiopathic hypereosinophilic syndrome characterized by marked basement membrane thickening of small intramyocardial vessels. We are unaware of previous reports showing the presence of an extensive thickening of the basement membrane of arteriolar and capillary intramyocardial vessels in eosinophilic myocarditis. Considering the findings in the present case, i.e., the focal nature of the lesions, the type of necrosis, and the diffuse microangiopathy, it can be hypothesized that the microvascular disease could play a role in the development of the myocardial changes.

Basement Membrane↗

[Diverticulitis of the cecum: description of 2 clinical cases].

The authors describe two cases of cecal diverticulitis pointing out the rarity of the disease in particular in Western countries. The disease is often asymptomatic although in the case of diverticulitis, which represent the most frequent complication of the disease, the patient becomes symptomatic. The symptomatology in these cases is similar to an acute appendicitis with which it is constantly confused. Surgery is the most common therapy and the type of operation is based on the clinical condition of the patient and local anatomical-surgical situation.

Cecal Diseases↗

Arterial-venous PCO2 gradient in early postoperative hours following myocardial revascularization.

OBJECTIVE: To investigate the utility of the arterial-venous PCO2 gradient (P(a-v)CO2) as a marker of the increased risk of postoperative complications in the early postoperative hours following myocardial revascularization. EXPERIMENTAL DESIGN: Prospective study. SETTING: The Postoperative Intensive Care Unit (ICU) of a University Hospital. PATIENTS: Thirty patients (28 males and 2 females; aged 39-70) that consecutively underwent myocardial revascularization. INTERVENTIONS: None. MEASURES: Thirty minutes following arrival at the ICU the hemodynamic parameters were recorder; the arterial and mixed venous hemogasanalyses were obtained; the mixed venous blood hemoglobin saturation (SvO2) and the O2 consumption (VO2) were calculated; and plasma lactate was determined. The arterial and mixed venous hemogasanalyses were determined again 90 minutes after the admission to the ICU. RESULTS: P(a-v)CO2 at 30 minutes was 8.1+/-2.3 mmHg and was only slightly lower at 90 minutes (7.5+/-2.3 mmHg) so that any significant influence of patient transport to the ICU could be ruled out. P(a-v)CO2 did not significantly relate with cardiac index, mixed venous blood O2 saturation, and blood lactate. Twenty-one patients (70%) showed P(a-v)CO2 values higher than 7 mmHg at 30 minutes: in comparison with the others they were characterized by higher arterial blood PCO2 (PACO2) (37+/-5 vs 32+/-3 mmHg; p<0.05) in spite of similar ventilatory variables, by higher mixed venous blood PCO2 (PVCO2) (47+/-6 vs 37+/-3 mmHg; p<0.01), and by lower cardiac index values (2.0+/-0.3 vs 2.3+/-0.6 1/min/m2; p<0.05). The patients that presented abnormally high P(a-v)CO2 values showed a higher rate of postoperative complications, including inadequate cardiac performance, cardiac arrhythmias, prolonged mechanical ventilation, increased plasma creatinine, and jaundice (11 patients out of 21 vs 1 patient out of 9; p<0.05). Finally P(a-v)CO2 was related with arterial-mixed venous O2 content difference (regarded as an index of O2 consumption), hematocrit, blood temperature and PACO2 by multiple linear regression (R=0.74; p<0.01). The coefficients of all factors but hematocrit were significant; hence, apart from the cardiac index, P(a-v)CO2 was influenced by the metabolic rate, the body temperature (possibly because of CO2 release during rewarming), and the impaired CO2 elimination through the lungs. CONCLUSIONS: P(a-v)CO2 represents a useful even if aspecific parameter to monitor patients during the early postoperative period after myocardial revascularization.

Adult↗

Vascular endothelial growth factor. Expression in human vulvar neoplastic and nonneoplastic tissues.

OBJECTIVE: To investigate the expression of vascular endothelial growth factor (VEGF) in human vulvar neoplastic and nonneoplastic tissues. STUDY DESIGN: Specimens were collected at the Vulvovaginal Clinic, Department of Obstetrics and Gynecology, University of Milan. Human vulvar neoplastic and nonneoplastic tissues were dissected and frozen immediately at -80 degrees C until RNA extraction. Five micrograms of total RNA from each sample was denatured and transferred to nitrocellulose and nylon membranes for dot blot hybridization with labeled [alpha-32P]dCTP cDNA probe for VEGF. RESULTS: Messenger RNA encoding VEGF was detected in all tissues studied. VEGF mRNA was highly expressed in vulvar epithelial neoplasia (VIN) associated with human papillomavirus infection and minimally expressed in invasive squamous cells carcinoma of the vulva. Nonneoplastic lesions, such as chronic inflammation, lichen sclerosus, lichen planus, squamous hyperplasia and squamous papilloma, were also assessed, and none had a significant difference in VEGF mRNA expression. CONCLUSION: The prominence of VEGF mRNA levels in particular cases of VIN demonstrated that VEGF may be involved in promoting a new vascular network as a basic condition for the progression or at least self-maintenance of those lesions.

Blotting, Northern↗

[Early complications and long-term results of the LeVeen peritoneo-venous shunt in the treatment of refractory ascites].

Results concerning 14 cirrhotic patients who underwent LeVeen peritoneo-venous shunt for refractory or complicated ascites are discussed. The most relevant early complications regard coagulation disorders (35.7%) with a 14.3% postoperative mortality. The functional result appears largely satisfactory, also in terms of long-term efficiency. Utility of a wide evacuation of ascitic fluid during the operation is underlined. Ascites drainage at operation doesn't compromise shunt function or renal resumption, furthermore it may prevent some life-threatening complications like DIC, esophageal varices rupture and congestive heart failure.

Aged↗

[The role of Enterobius vermicularis in etiopathogenesis of appendicitis].

The authors present 14 cases of enterobiasis of appendix observed between 1991-94, on a total of 1093 appendectomies. The presence of the parasite was associated, in the majority of cases, to a chronic appendicitis. The symptomatology imitates an attack of acute appendicitis, but the true nature of the disease is diagnosed only through a histological examination. There is probably an etiopathogenic relationship between. E. vermicularis and chronic appendicitis, whereas the relationship between the parasite and acute appendicitis is rare and very disputed.

Adolescent↗

Prevention of in vitro protein thermal aggregation by the Sulfolobus solfataricus chaperonin. Evidence for nonequivalent binding surfaces on the chaperonin molecule.

We have studied the effects of the Sulfolobus solfataricus chaperonin on the aggregation and inactivation upon heating of four model enzymes: chicken egg white lysozyme (one 14.4-kDa chain), yeast alpha-glucosidase (one 68.5-kDa chain), chicken liver malic enzyme (four 65-kDa subunits), and yeast alcohol dehydrogenase (four 37.5-kDa subunits). When the proteins were heated in the presence of an equimolar amount of chaperonin, 1) the aggregation was prevented in all solutions; 2) the inactivation profiles of the single-chain enzymes were comparable with those detected in the absence of the chaperonin, and enzyme activities were regained in the solutions heated in the presence of the chaperonin upon ATP hydrolysis (78 and 55% activity regains for lysozyme and alpha-glucosidase, respectively); 3) the inactivation of the tetrameric enzymes was completely prevented, whereas the activities decreased in the absence of the chaperonin. We demonstrate by gel filtration chromatography that the chaperonin interacted with the structures occurring during thermal denaturation of the model proteins and that the interaction with the single-chain proteins (but not that with the tetrameric proteins) was reversed upon ATP hydrolysis. The chaperonin had nonequivalent surfaces for the binding of the model proteins upon heating: the thermal denaturation intermediates of the single-chain proteins share Surfaces I, while the thermal denaturation intermediates of the tetrameric proteins share Surfaces II. ATP binding to the chaperonin induced a conformation that lacked Surfaces I and carried Surfaces II. These data support the concept that chaperonins protect native proteins against thermal aggregation by two mechanistically distinct strategies (an ATP-dependent strategy and an ATP-independent strategy), and provide the first evidence that a chaperonin molecule bears functionally specialized surfaces for the binding of the protein substrates.

Alcohol Dehydrogenase↗

Anisotropy decay measurement of segmental dynamics of the anion binding domain in erythrocyte band 3.

Time-resolved anisotropy was utilized to detect nanosecond segmental motions of the band 3 intramembrane domain. Band 3 at lysine 430 was fluorescently labeled in ghost membranes by fluorescein or eosin maleimide treatment of intact human erythrocytes followed by hypotonic lysis. Single lifetimes for fluorescein (3.8-4.1 ns) and eosin (3.2-3.4 ns) were observed. Phase-modulation measurement of anisotropy decay indicated a segmental motion model, r(t) = exp(-t/tau 1c)[r infinity + (ro-r infinity) exp(-t/tau 2c)], defined by rotational correlation times corresponding to band 3 segmental motion (tau 1c, 30-70 ns) and rapid fluorescein motion in its binding pocket (tau 2c, 200-400 ps), and a residual anisotropy (r infinity, 0.23-0.28) describing hindered fluorescein motion. In PBS at pH 7.4, tau 1c, tau 2c, and r infinity were 44 ns, 307 ps, and 0.24, respectively, predicting a steady-state anisotropy of 0.24, in agreement with the measured value of 0.23. Factors that might influence band 3 structure/dynamics were examined. Whereas pH (range 5-10) had little effect on r(t), [NaCl] addition (0-150 mM) remarkably decreased tau 1c from 68 to 44 ns. The decrease in tau 1c correlated with solution ionic strength, and did not depend on osmolality (studied by mannitol addition), or specific anion interactions (comparing Cl, Br, F, SO4, citrate). The ionic strength effect was not observed in fluorescein-labeled carbonic anhydrase and trypsin-cleaved band 3, suggesting a specific effect on intact band 3. Anisotropy decay was relatively insensitive to external lectin or internal 2,3-DPG binding, but was sensitive to temperature, membrane fluidity, urea denaturation, fluid-phase viscosity, and aldehyde fixation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

The purification, cloning, and high level expression of a glutaredoxin-like protein from the hyperthermophilic archaeon Pyrococcus furiosus.

A protein has been purified to homogeneity from crude extracts of the hyperthermophilic archaeon Pyrococcus furiosus based on its ability to catalyze the reduction of insulin disulfides in the presence of dithiothreitol; the protein has a molecular mass of 24.8 kDa and a pI of 4.9, and it is highly heat-stable. The first 29 amino acid residues at the N terminus of the P. furiosus protein were determined by Edman degradation, and its gene was cloned in Escherichia coli. The amino acid sequence derived from the DNA sequence contains the CPYC sequence, which is typical of the active site of glutaredoxin (also called thioltransferase). The C-terminal portion of the P. furiosus protein, containing the conserved sequence, shows sequence similarity with glutaredoxins from different sources. The P. furiosus protein can reduce disulfide bonds in L-cystine in the presence of GSH (the thioltransferase activity) with an optimum pH of 8.0. The expression of the P. furiosus protein, with full activity, in E. coli at a very high level (21% of total soluble protein) is described; the recombinant protein was purified to homogeneity by merely two successive heat treatments and gel filtration chromatography. The features of the P. furiosus protein here described are discussed in light of the current knowledge about the ubiquitous family of protein disulfide oxidoreductases.

Amino Acid Sequence↗

Laparoscopic versus conventional surgery for suspected appendicitis in women.

The diagnosis of appendicitis remains uncertain in female patients and laparoscopy has been suggested as a valid diagnostic tool. The laparoscopic approach has recently also been proposed for the treatment of acute appendicitis, though its real value is still under debate. A clinical and economic prospective evaluation of laparoscopic surgery over a 1-year period in female patients is reported. The study involved 38 patients presenting with signs of appendicitis and assigned to open (18) or laparoscopic surgery (20). The two groups were comparable as regards age and clinical presentation of the disease. The duration of the procedures was similar (60 min). Morbidity was comparable (3 vs 2). The ratio of negative appendectomy (50% vs 44%) was also similar, but the laparoscopic approach enabled a higher number of certain diagnoses (9/10 vs 3/8 p > 0.05). No significant differences were observed in the median postoperative stay (3 days for laparoscopy and 4 for surgery) or in the days needed to return to normal activity (15 vs 18). The cosmetic satisfaction was higher for the laparoscopic patients. The cost of the laparoscopic approach, however, was much higher than for conventional surgery. Our results suggest that laparoscopy is a useful diagnostic tool in female patients, but that laparoscopic appendectomy should be considered with some caution in times of restricted financial resources.

Acute Disease↗

The use of technetium-99m hexamethylpropylene amine oxime labelled granulocytes with single-photon emission tomography imaging in the detection and follow-up of recurrence of infective endocarditis complicating transvenous endocardial pacemaker.

In this case report we present a patient with a recurrence of subacute bacterial infectious endocarditis (IE) complicating a transvenous endocardial pacemaker. Technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) labelled granulocytes were used for diagnosis and follow-up under medical treatment only, since surgical removal of the pacemaker lead was ruled out because of the general condition of the patient. Single-photon emission tomography (SPET) imaging displayed the active lesion previously suspected on echography. At the end of antibiotic therapy, SPET indicated a favourable disease outcome whereas echocardiographic abnormalities remained nearly unchanged. The medical treatment had eradicated the IE, and the patient did well for more than 1 year thereafter.

Aged↗

Optimum tomographic reconstruction parameters for HMPAO brain SPET imaging: a practical approach based on subjective and objective indexes.

The purpose of this study was to define an optimal strategy for the tomographic reconstruction procedure in routine brain single-photon emission tomography (SPET) studies, including the number of projections, filter function and matrix size. A set of projection data with different count densities was obtained from a technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) brain SPET acquisition from one volunteer. The projections were reconstructed with different filters and the quality of the reconstructed images was determined using both a subjective observer rating score and the Gilbert index. For each count density, the observers' choice corresponded to images with the lowest Gilbert index. The noise level in brain SPET sections was estimated and correlated with the fractal dimension. The results of this study indicate that although noise represents a fundamental component of brain SPET imaging, image quality also depends on the reconstructed spatial resolution. Image quality is satisfactorily described by fractal dimension. In addition the optimal filter function depends on the available count density. For high count levels, optimal reconstruction may be obtained by using a high-resolution matrix and a slightly smoother reconstruction filter. When count densities are low, best results are obtained by using a low-resolution matrix and a sharper filter. Finally, this study suggests that image quality is not influenced by the number of projections for equivalent count densities. These results were confirmed by 30 HMPAO brain SPET studies acquired in a routine clinical setting.

Brain↗

Expression and extensive characterization of a beta-glycosidase from the extreme thermoacidophilic archaeon Sulfolobus solfataricus in Escherichia coli: authenticity of the recombinant enzyme.

The gene coding for the beta-glycosidase from the archaeon Sulfolobus solfataricus has been overexpressed in Escherichia coli. The enzyme was purified to homogeneity with a rapid purification procedure employing a thermal precipitation as a crucial step. The final yield was 64% and the purification from the thermal precipitation was 5.4-fold. The expressed enzyme shows the same molecular mass, thermophilicity, thermal stability, and broad substrate specificity, with noticeable exocellobiase (glucan 1,4-beta-D-glucosidase) activity, of the enzyme purified from S. Solfataricus. We provide evidence that the beta-glycosidase can assume its functional state in E. coli without the contribution of N-epsilon-methylated lysine residues.

Amino Acid Sequence↗

Left ventricular diastolic filling in diabetes mellitus with and without hypertension.

Left ventricular diastolic filling by Doppler echocardiography was investigated in 84 diabetic patients without evidence of heart disease and in 84 normotensive nondiabetic age- and sex-matched control subjects. Diabetic patients were subdivided into two groups on the basis of the presence of arterial hypertension. Group 1 comprised 41 normotensive diabetic patients (19 men, 22 women, mean age 63.7 +/- 9.1 years); Group 2 comprised 43 hypertensive diabetics (15 men, 28 women, mean age 65.6 +/- 9.6 years). Doppler measures of diastolic filling were significantly altered in the two groups as compared with control subjects. Peak atrial flow velocity, velocity integral for the atrial filling period, and atrial filling fraction were increased, whereas the ratio of peak early to peak atrial flow velocity and the ratio of flow velocity integrals were decreased, especially in Group 2 patients. Thirteen patients in Group 1 (32%) and 17 in Group 2 (40%) had evidence of diastolic dysfunction, as assessed by the presence of at least two independent abnormal indices (outside age-corrected 95% confidence interval). In each group, patients with altered diastolic filling differed slightly from diabetic patients with normal Doppler indices, tending to increased wall thickness and left ventricular mass. In conclusion, diastolic filling of the left ventricle is frequently altered in diabetic patients and is adversely affected by arterial hypertension whose coexistence further impairs left ventricular relaxation.

Aged↗