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Biomedical subjects

L Rossi

Publications and source records attributed to L Rossi.

At least 199 records · Page 11Linked to original sources
PubMed1996

[Anatomo-clinical and epidemiologic study of Chagas disease].

Chagas' disease is a chronic form caused by a parasite, the Trypanosoma Cruzi, endemic of Latin America. The Trypanosoma Cruzi is transmitted by hematophageous bugs, particularly in dilapidated rural areas. Three phases of the disease can be distinguished: 1) acute phase, with high tissue and blood parasitic involvement; 2) undetermined phase, in which the diagnosis requires sophisticated clinical investigations; 3) chronic phase (10-30 years following the infection), characterized particularly by cardiac disease manifestations. The present 120 patients were subdivided into four groups: 1) 43 asymptomatic serum-positive subjects; 2) 25 serum-positive patients with electrocardiographic abnormalities; 3) 14 serum-positive patients with cardiomegaly; 4) 38 with classic chagasic cardiopathy. Comparative studies among these four groups were carried out employing Holter monitoring (24h), ergometric and phonomechanographic tests, M-mode and bidimensional echography and radionuclide ventriculography. A significant difference between the first 3 groups and, respectively, the fourth group (p < 0.001) was found. Deadly-risk (p < 0.001) manifestation were pointed out, such as a third tone, right bundle branch block with left anterior hemiblock and left ventricle's dilation. Autoptic controls were performed and in 4 patients the myocardial biopsy showed C3 and IgG deposition in capillaries and myocardial fibers, at electron microscopic examination, some thickening of capillary and myocytic basal membrane, interstitial collagen proliferation, besides non-specific myocellular abnormalities were detected.

Adolescent↗
PubMed1996

[Secondary prevention of myocardial ischemia. From theory to clinical reality: preliminary results of the EUROASPIRE study in Italy. European Action on Secondary Prevention through Intervention to Reduce Events].

EUROASPIRE study has been carried out in 9 European countries with the aim of assessing coronary risk factors in high-risk patients admitted to hospital to undergo coronary revascularization procedures (coronary angioplasty or coronary artery bypass grafting) or because of angina or myocardial infarction. The results of the initial stage of the study in Italy, investigating the data from 691 hospital medical records, showed that management of risk factors in these patients was inferior than expected. In particular, the prevalence of hyperlipidaemia (63%), hypertension (40%) and diabetes (27%) was remarkably high. These results suggest that there is still a need for secondary prevention of coronary heart disease.

Aged↗
PubMed1996

[Protective efficacy of 3 anesthetic methods with reference to surgical stress in children].

Hormonal-metabolic stress responses have beyond doubt an effect on morbidity/mortality related to surgery. The present study med to determine which anaesthetic technique could afford the best protection in children, through analysis of the perioperative cortisol, prolactin and beta-endorphin plasma levels. Thirty-six young patients 3-10 years old, ASA I-II, scheduled for hypospadias or vesicoureteral reflux surgery of a duration > 60 min, were randomized into three groups (n = 12). Children of group I were given initially propofol and fentanyl then isoflurane 1%; group 2 received TIVA with propofol and fentanyl, group 3 received initially propofol then an epidural lumbar block with bupivacaine 0.25% (single shot) and continuous propofol i.v. infusion. Cortisol, prolactin and beta-endorphin levels increased significantly in group 1 only. No significant differences were observed between group 2 and 3. Early postoperative analgesia was better in group 3. These data suggest that TIVA and particularly epidural block could afford a better protection against the surgical stress in children submitted to subumbilical operations.

Anesthesia, General↗
PubMed1996

[Hepatic resection in the fetal rabbit. Histologic comparison of tissue regeneration in the fetus versus the adult].

Fetal tissues present peculiar features of repair after injury. Although the development of fetal hepatocytes have already been studied in vitro and in transplant models, an in vivo study of fetal liver regeneration is still missed in the literature, to the best of our knowledge. Eight time-dated pregnant California rabbits (23, 24, 25, 30 days of gestational age) and 2 adult male California rabbits were anesthetized following a standardized i.v. protocol (ketamine 50 mg/kg; xilazine 5 mg/kg; propiopromazine 0.75 mg/kg; spontaneous breathing; no anesthetic gas). All the pregnant does underwent a midline laparotomy and a minimal hysterotomy to approach a fetus per each animal. In 2 cases, 1 fetus was delivered and prior to sacrifice the fetal liver was sampled in toto (30 days of gestational age). These pregnancies were allowed to continue to term and were uneventful with a full-term spontaneous delivery of the remaining fetuses. In the other 6 pregnancies, after the hysterotomy, the fetal abdomen was entered through a right-sided longitudinal incision and the liver was partially resected by thermocauterization. Fetal abdomen was closed in 1 layer (non absorbable suture 7-0). The fetus was then returned in the uterus and, after amniotic fluid restoration with warmed saline, the hysterotomy was sutured in double layer (polyglycolic 5-0). Maternal abdomen was closed in 1 layer (polyglycolic 4-0) and the skin in a continuous overlying fashion (silk 3-0). The abdominal cavity of the 2 adult male rabbits was entered through a right subcostal incision. Partial liver resection was performed, and abdominal and skin closure followed the same techniques used for the pregnant does. The treated livers were then sampled in toto at 24, 48, 72 hrs and 4 days after surgery from the fetuses, and at 7 days from the adult rabbits. Histological stains were: H & E; Van Gieson; Masson; Alcian Bleu; PAS. Fetal histology showed a low inflammatory reaction poor in PMN cells with minimal deposition of collagen and a high amount of glycogen in the hepatocytes. The inflammatory response to resection was much more evident in the adult samples as much as the abundant intra and extra-cellular deposition of collagen associated to a minor amount of intracellular glycogen. The peculiar features of liver regeneration in the fetus, deserve further experimental studies.

Animals↗
PubMed1996

[Solitary fibrous mesothelioma of the peritoneum. Considerations of a clinical case in our observation].

The authors report a case of so-called solitary fibrous peritoneal mesothelioma which was successfully operated on. Their case is compared with the few cases reported in the literature. Analysis of findings shows the fibrous peritoneal mesothelioma to be a solitary well defined tumor, generally of considerable size at the time of the diagnosis, very similar to the fibrous metothelioma of the pleura. It is believed to originate in the sub-mesothelial connective tissue. Surgery provides a definitive cure.

Adult↗
PubMed1995

2',3'-Dideoxycytidine metabolism in a new drug-resistant cell line.

2',3'-Dideoxycytidine (ddC) is a nucleoside analogue that inhibits human immunodeficiency virus type 1 (HIV-1) replication in vitro and is currently used in the therapy of acquired immune deficiency syndrome (AIDS). This compound exerts a delayed cytotoxicity due to inhibition of mitochondrial DNA (mDNA) synthesis. Long-term exposure of U937 human monoblastoid cells to ddC resulted in a time- and concentration-dependent decrease in mDNA content and Rhodamine 123 fluorescence. However, after 2 months on 0.1 microM ddC, a drug-resistant cell line (U937-R) with 66% of the normal amount of mDNA was isolated. ddC transport in U937 and U937-R cell lines was similar. In contrast, U937-R accumulated ddC phosphorylated derivatives at a much lower rate and to a reduced concentration into acid-soluble material. The rate of 2',3'-dideoxycytidine 5'-triphosphate (ddCTP) formation in U937-R cells was almost one-third of that measured in normal cells, although the rate of ddCTP catabolism was similar in both cell lines. Dideoxyliponucleotide (ddCDP-choline and ddCDP-ethanolamine) formation was also much slower (between one-half and one-third as fast) in U937-R than in control cells, although catabolism occurred at similar rates. ddC was phosphorylated by a cytoplasmic deoxycytidine kinase in both cell lines. This enzyme showed Km values for ddC of 80 +/- 7 and 140 +/- 9 microM in U937 and U937-R cells respectively. Furthermore, Vmax was 12 +/- 1.1 and 7.8 +/- 0.5 pmol/min per mg of protein in U937 and U937-R. Thus resistance to ddC toxicity may be due to cells' decreased ability to accumulate intracellular ddC anabolites, which may depend on cytoplasmic deoxycytidine kinase.

Biological Transport↗
PubMed1995

[Intramuscular injections--an outdated form of administration? 6 cases of Staphylococcus aureus sepsis following intramuscular injections].

Intramuscular injections can lead to local and systemic complications, such as abscess and sepsis. These are often caused by Staphylococcus aureus, occur in immunocompromised as well as in immunocompetent persons, and often need extensive medical and surgical treatment. We describe 6 cases with sepsis and multiple abscesses caused by Staphylococcus aureus after intramuscular injections. In view of possible serious complications, the indication for intramuscular injection as a method of drug administration is critically analyzed.

Abscess↗
PubMed1995

Modulated red blood cell survival by membrane protein clustering.

Human and murine blood cells treated with ZnCl2 and bis(sulfosuccinimidyl)suberate (BS3) (a cross linking agent) undergo band 3 clustering and binding of hemoglobin to red blood cell membrane proteins. These clusters induce autologous IgG binding and complement fixation, thus favouring the phagocytosis of ZnCl2/BS3 treated cells by macrophages. The extension of red blood cell opsonization can be easily modulated by changing the ZnCl2 concentration in the 0.1-1.0 mM range thus providing an effective way to affect blood cell recognition by macrophages. In fact, murine erythrocytes treated with increasing ZnCl2 concentrations have proportionally reduced survivals when reinjected into the animal. Furthermore, the organ sequestration of ZnCl2/BS3 treated cells strongly resembles the typical distribution of the senescent cells. Since the ZnCl2/BS3 treatment can also be performed on red blood cells loaded with drugs or other substances, this procedure is an effective drug-targeting system to be used for the delivery of molecules to peritoneal, liver and spleen macrophages.

Animals↗
PubMed1995

Modulation of phenotypic expression of fibroblasts by alteration of the cytoskeleton.

Several studies indicate that the cytoskeleton may be involved in modulating the cellular response to environmental signals. We have studied the role of the cytoskeleton in regulating glycosaminoglycan (GAG) synthesis and secretion, hyaluronate (HA) endocytosis, the activities of hexoglycosidases, protein synthesis and secretion. Fibroblasts were treated with colchicine (1-8 microM) and nocodazole (1 or 4 microM) to alter microtubules or cytochalasin B (0.5-4 microM) to alter microfilaments. Colchicine inhibited GAG synthesis and secretion in a concentration-dependent manner. It reduced protein and sulphated GAG secretion, while HA secretion was not affected. Concentration-dependent disruption of microtubules from the periphery toward the cellular centre with nocodazole inhibited only the secretion of GAG. Centrosomal microtubles appeared to be required to promote GAG synthesis; intact microtubules promoted the transport of secretory products, intercompatmental transport of lysosomal enzymes and lysosome maturation, but not protein synthesis and HA secretion. Cytochalasin B treatment inhibited, in a concentration-dependent manner, the synthesis and secretion of GAGs and proteins, and the endocytosis of HA. Intact microfilament meshworks appeared to be required to promote synthesis and secretion of proteins and proteoglycans and to contribute to the transmembrane control of receptor-mediated endocytosis. Drug treatment of concanavalin A (Con A)-stimulated fibroblasts inhibited the stimulation of GAG synthesis. It is probable that this effect may result, in part, from drug-induced effects on Con A-mediated endocytosis.

Animals↗
PubMed1995

Effect of antiviral treatments on the bone marrow in murine aids.

Blood cytopenia is a common feature in HIV infection, occurring in up to 70% of patients with AIDS. Since at present it is not clear to what extent this is intrinsic to HIV infection or due to opportunistic infections and antiretroviral agents we have investigated the long-term effects of conventional and new antiviral drugs on the bone marrow of normal and immunodeficient mice. The results show that azidothymidine (AZT), dideoxycytidine (DDC) and dideoxycytidine 5'-triphosphate (DDCTP) alone or in combination are all effective in inhibiting the expression of the retroviral protein Pr60gag in bone marrow cells. However, DDCTP was the most effective in preventing bone marrow cytopenia. Combined treatments of AZT plus DDCTP result in a reduction in erythroid precursors compared to that resulting from DDCTP administration, while DDC plus DDCTP results in a differential cell count similar to that found in uninfected mice. Thus, the bone marrow in murine AIDS may prove useful as a model for therapy of retroviral infections and for treating blood cytopenias.

Animals↗
PubMed1995

2',3'-Dideoxycytidine induced drug resistance in human cells.

2',3'-Dideoxycytidine (ddC) is a nucleoside analogue that inhibits HIV-1 replication in vitro and is currently used in AIDS therapy. This compound exerts a delayed cytotoxicity due to inhibition of mitochondrial DNA (mDNA) synthesis. We have found that long term exposure of U937 human monoblastoid cells to ddC allowed the selection of a drug-resistant cell line (U937-R) with 66% mDNA, normal ddC transport and altered deoxycytidine kinase kinetic properties. In this paper we show that U937-R cells contain an increased number of mitochondria per cell and a reduced copy number of mDNA/mitochondria. Furthermore, the intracellular concentrations of deoxycytidine 5'-triphosphate (dCTP) and 2',3'-dideoxycytidine 5'-triphosphate (ddCTP) are also reduced although with a higher dCTP/ddCTP ratio in U937-R compared to the parental cells. This mechanism of drug resistance, with drug-resistance based on viral mutations, can provide an explanation for drug failure in antiviral therapy.

Cell Line↗
PubMed1995

FIV infection of macrophages: in vitro and in vivo inhibition by dideoxycytidine 5'-triphosphate.

We have evaluated in vitro and in vivo whether it is possible to protect cat macrophages from feline immunodeficiency virus (FIV) infection by the administration of dideoxycytidine 5'-triphosphate (DDCTP). Since cell membranes are impermeable to phosphorylated drugs we have encapsulated DDCTP into autologous erythrocytes and modified erythrocyte membranes to target these drug-loaded cells to macrophages. DDCTP-loaded erythrocytes reduced FIV production by macrophages infected in vitro or obtained from naturally or experimentally infected cats. The same treatment protected the majority of peritoneal macrophages during a 7 month experimental FIV infection and reduced the percentage of circulating lymphocytes stained with an anti-p24 antibody. These results suggest that the administration of nucleoside analogues in phosphorylated form is feasible and their targeting to macrophages reduces FIV infection in vitro and in vivo.

Animals↗
PubMed1995

Sudden cardiac death in the indeterminate phase of Chagas' disease associated with acute infarction of the right carotid body.

We recently came across a case of a patient in the indeterminate phase of Chagas' disease who died suddenly with cardiac arrhythmia associated with acute infarction of the right carotid body due to occlusive thrombosis in the glomic artery. Although the available data in this case do not offer definite evidence to support a cause-and-effect relationship between carotid body infarction and patient's sudden cardiac arrest, it is very likely that the acute infarction of the carotid body could be the distinct morphological counterpart of the functional disturbance. The infarction would affect the vagal-sympathetic interactions augmenting sympathetic action.

Carotid Body↗
PubMed1995

Reduced serum levels of immunoreactive erythropoietin in patients with cirrhosis and chronic anemia.

Chronic anemia is frequently observed in patients affected by cirrhosis. To investigate the possible role of erythropoietin (Epo) in the pathogenesis of anemia in cirrhosis, we measured the immunoreactive Epo levels and the respective hemoglobin (Hb) concentrations in 48 anemic and nonanemic cirrhotic patients and in a control group of healthy subjects and patients with iron-deficiency anemia. Epo concentrations were determined in serum using a sensitive enzyme immunoassay. The regression curve between Epo values and Hb concentrations showed a significant inverse exponential trend both in cirrhotic patients (r = -.55; P < .0001) and controls (r = -.92; P < .0001). In a semilogarithmic plot, the line slope obtained in cirrhotic patients was significantly lower (P < .005) than that of controls, suggesting a blunt Epo response to anemia in cirrhosis. Moreover, covariance analysis showed that the Epo levels for a given degree of anemia were further reduced in the patients with a more severe disease, suggesting a close relation between cirrhosis and the mechanisms involved in the derangement of the Epo feedback system. Finally, the Epo concentrations measured in the cirrhotic patients without anemia did not significantly differ from Epo values obtained in healthy subjects. An impaired Epo response may play a role in maintaining low Hb concentrations in cirrhotic patients with anemia. However, the evidence of a residual Epo response to anemia in cirrhosis and the presence of normal basal Epo levels in nonanemic cirrhotic patients do not support an inadequate Epo secretion as one of the primary causes of anemia in cirrhosis.

Adult↗
PubMed1995

Noninvasive detection of functional alterations of the arterial wall in IDDM patients with and without microalbuminuria.

OBJECTIVE: To test endothelial function in a group of 10 normoalbuminuric and eight microalbuminuric insulin-dependent diabetes mellitus patients (ages 28 +/- 3 [mean +/- SE] and 28 +/- 1 years, respectively), in comparison with 16 control subjects (age 35 +/- 2 years, normal subjects vs. diabetic subjects P = NS), to identify prestructural abnormalities of the arterial wall. An early stage of vascular involvement seems in fact to be characterized by functional alterations of endothelial control on vascular tone and wall interaction with circulating cells. Furthermore, many recent studies suggest the importance of microalbuminuria as an early marker not only of nephropathy but also of retinopathy and macroangiopathy. RESEARCH DESIGN AND METHODS: Endothelium-mediated flow-dependent vasodilation and endothelium-independent vasodilation (induced by glyceryl trinitrate administration) were evaluated in the right common femoral artery by echo-Doppler ultrasound. Arterial wall distensibility was evaluated at the common femoral artery by an echo-tracking system. RESULTS: In spite of a comparable increase in flow velocity, endothelium-mediated vasodilation was significantly reduced in diabetic subjects, particularly in microalbuminuric patients. Endothelium-independent vasodilation was also significantly impaired in diabetic subjects, particularly in microalbuminuric subjects; whereas arterial wall distensibility, an index of the viscoelastic properties of the wall, was similar in the three groups. CONCLUSIONS: These results confirm a reduced vasodilatory capacity in diabetes mellitus, with a more marked alteration in microalbuminuric diabetic subjects. This reliable, noninvasive evaluation of arterial function is particularly useful for early diagnosis of vascular involvement.

Adult↗
PubMed1995

Ascites free-water dynamics in decompensated cirrhosis: effects of acute and chronic frusemide treatment.

OBJECTIVE: To evaluate the effects of acute (60 mg intravenous bolus) and protracted (75 mg per day orally for 1 week) frusemide administration on ascites volume, free-water peritoneal clearance (FWPC), intra-abdominal pressure (IAP) and body weight in 30 decompensated cirrhotic patients. METHODS: Individual ascites volume and FWPC were estimated by means of a previously validated methylene-blue dilution test. RESULTS: All the investigated parameters showed a significant reduction after the protracted diuretic treatment (ascites volume 9.0 +/- 1.0 to 4.9 +/- 0.61, P < 0.001; FWPC 99.8 +/- 6.7 to 76.2 +/- 6.6 ml/min, P < 0.001; IAP 17.0 +/- 1.5 to 11.3 +/- 0.8 cmH2O, P < 0.001; body weight 75.2 +/- 1.9 to 66.3 +/- 1.8 kg, P < 0.001). A significant FWPC reduction (89.5 +/- 14.6 to 68.8 +/- 12.1 ml/min, P < 0.02) was also observed after the acute frusemide administration in the absence of any appreciable modifications to ascites volumes and IAP. CONCLUSION: Frusemide treatment appears to be able to exert a direct significant effect on FWPC, which does not appear to be mediated by ascites volume or IAP modifications.

Abdomen↗