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Biomedical subjects

S Stella

Publications and source records attributed to S Stella.

At least 19 recordsLinked to original sources
PubMed1999

Nephrotic syndrome as a clinical manifestation of graft-versus-host disease (GVHD) in a marrow transplant recipient after cyclosporine withdrawal.

GVHD is one of the most frequent complications of BMT and recently nephrotic syndrome (NS) has been described as a manifestation of chronic GVHD. Here, we present an AA patient who developed NS 1 year after BMT when cyclosporine was stopped. Renal biopsy showed focal sclerosis associated with membranous deposits. He also had other clinical manifestations of chronic GVHD: sicca-like syndrome and colestasis. After 15 days of CsA therapy, he experienced a remarkable improvement in the NS and GVHD as a whole. We comment on immunological mechanisms that could be involved in the pathogenesis of this manifestation.

Adult↗
PubMed1998

Microalbuminuria in IDDM is associated with increased expression of monocyte procoagulant activity.

Microalbuminuria, the early phase of diabetic nephropathy, is associated with an increased risk of atherothrombosis. Monocytes play an important part in the pathogenesis of atherosclerosis and in the activation of haemostasis. However, procoagulant activity is poorly understood in Type I (insulin-dependent) diabetes mellitus, particularly in the presence of microalbuminuria. This study aimed to evaluate spontaneous and endotoxin-induced monocyte procoagulant activity in insulin-dependent diabetic patients with normoalbuminuria or microalbuminuria. Seventeen patients with microalbuminuria, 28 with normoalbuminuria and 26 healthy control subjects matched for age, sex, body mass index and smoking habit were studied. Mononuclear cells from peripheral venous blood were incubated with or without bacterial lypopolysaccharide. Spontaneous procoagulant activity and procoagulant activity after 3 h and 6 h of incubation were calculated. Spontaneous procoagulant activity values were similar in the three groups. After 3 h and 6 h incubation with bacterial lypopolysaccharide, procoagulant activity values were slightly, but not statistically significantly, higher in the normoalbuminuric diabetic group than in control group, and significantly higher in microalbuminuric diabetic group than in control group (p < 0.01). The increased endotoxin-induced monocyte procoagulant activity helps to explain the link between microalbuminuria and the increased risk of atherothrombosis in patients with Type I diabetes.

Adult↗
PubMed1998

Stability of resveratrol over time and in the various stages of grape transformation.

Research has been carried out with the purpose of verifying whether the resveratrol content in the skins or pomace of grapes stored for a long period of time without any particular protection with regard to temperature and humidity, could lead to a reduction of the content of this product detected at the beginning of the processing of grapes in vinification procedures. The dosages carried out both on the grape skin and on the pomace taken after fermentation and stored for a certain period of time, as well as on the products derived from alcoholic distillation, did not show the expected alterations in resveratrol content, considering their storage in bad environmental conditions for a long period of time. The results obtained confirm that resveratrol, unlike anthocyanins and other polyphenols, is stable and stores well over time.

Antioxidants↗
PubMed1997

Activated protein C resistance in type I diabetes.

OBJECTIVE: To compare activated protein C (aPC) sensitivity in 37 type I diabetic patients and 33 healthy control subjects. RESEARCH DESIGN AND METHODS: In this study, 37 type I diabetic patients and 33 healthy control subjects without personal or familial history of venous thrombosis and coagulation disorders, infections, intercurrent conditions, serum lupus anticoagulant, clinical cardiovascular complications, or drugs were examined. RESULTS: The aPC ratio (aPTT [activated partial thromboplastin time] with and without aPC) was significantly lower in the type I diabetic patients than in the control subjects (P = 0.005). CONCLUSIONS: These results suggest that the final steps of the protein C/S inhibiting system could be abnormal in type I diabetes.

Adult↗
PubMed1997

Targeted screening for elongation factor Tu binding antibiotics.

The development of a screen targeted to antibiotics which bind elongation factor Tu (EF-Tu) is described. The method was based on selection of antimicrobial activities which were antagonized by exogenous EF-Tu. Kirromycin, a known inhibitor of EF-Tu, was positive in this screen. Among 47,000 microorganisms screened, several producers of kirromycin-type antibiotics were detected and the novel antibiotics GE2270 and GE37468 were discovered. These thiopeptide molecules constitute, along with amithiamycin, a novel class of antibiotics acting on EF-Tu.

Actinomycetales↗
PubMed1997

[Endoscopic fragmentation of gastric phytobezoars as a valid alternative, in selected cases, to traditional surgery].

Three cases of gastrointestinal bezoar are described. Two were submitted to conventional surgery and one to endoscopic fragmentation. The natural and postoperative pathophysiologic mechanisms responsible for the formation of bezoars were studied. The condition is generally asymptomatic, the clinical presentation being similar to that of gastritis and/or duodenitis. Endoscopy is the non-invasive technique of choice in the diagnosis of gastric bezoars. Treatment of these lesions in day-endoscopy consists in removal of the bezoar if less than 3 cm in diameter and fragmentation if larger in diameter followed by extraction of any fragments over 1 cm to prevent the risk of intestinal obstruction. Long term maintenance therapy with cisapride or metoclopramide is then immediately administered for preventive purposes, and it is also used in patients submitted to traditional gastric and/or duodenal surgery.

Adult↗
PubMed1997

[Perineal surgical approach in the treatment of some disorders of the rectoanal function (fecal incontinence and obstructive constipation)].

A global experience in the surgical perineal approach to the treatment of alterations of recto-anal function (fecal incontinence and obstructed defection) is reported. Surgical techniques and results in four cases of fecal incontinence operated and surgical treatment of 14 patients suffering from obstructed defecation, due to organic obstacles (4 cases) or functional abnormalities (rectocele 10 cases) are discussed. Indications, surgical techniques as well as the obtained results are described.

Aged↗
PubMed1996

[Apudomas: nosographic and physiopathological aspects].

The authors intend to contribute to the knowledge of this complex and in part not fully defined subject of apudomas, in particular with regard to classification criteria and physiopathological aspects. After having examined the characteristics of these neoplasias (probably common embryonal origin, similar radioimmunological, immunohistochemical and ultrastructural characteristics, the capacity to convert amine precursors into amines), the authors focus on the most significant aspect of these carcinoids which, in the light of current knowledge, possess varying but undisputed degrees of biological aggressiveness. They also highlight the importance of the gastroenteric tract as an organ with an endocrine function and lastly affirm the value of the classification which, using the pancreas as the reference organ, distinguishes endocrine neoplasias in this tract into entopic and ectotopic examples.

Apudoma↗
PubMed1995

Contribution of mass spectrometry to the structural confirmation of components of the antibiotic GE2270 complex.

The GE2270 complex consists mainly of GE2270 A (MW 1289), a thiazolyl peptide antibiotic whose structure originates from the modification of a chain of 14 amino acids in a process which creates six thiazole rings and one pyridine. Together with the main component, a number of structurally related molecules are co-produced in small quantities by fermentation. A preparative high-performance liquid chromatrography method was developed to isolate GE2270 factors B1, B2, C1, C2a, C2b, D1, D2, E and T. Their structures, preliminarily determined by 1H-nuclear magnetic resonance spectroscopy in comparison with GE2270 A, were confirmed by low and high resolution fast-atom bombardment mass spectrometry and studies on the intact molecules and on their main hydrolysis products. Their molecular weights range from 1246 to 1306 Da. The structural differences between the factors lie in the extent of methylation and/or oxidation of thiazole rings (D and E) and asparagine, and in the aromatization of the oxazoline ring.

Anti-Bacterial Agents↗
PubMed1995

Bioconversion capacity of Streptomyces sp GE44282, a producer of the antibiotics heneicomycin and aurodox.

Streptomyces sp GE44282 was isolated in the course of a screening program for novel antibiotics. It co-produces heneicomycin and aurodox, two kirromycin-type antibiotics, which differ by the presence of an hydroxyl group at the C30 position of aurodox. Heneicomycin is converted into aurodox both by growing and resting cells of Streptomyces sp GE44282 and by the producer of aurodox, Streptomyces goldiniensis ATCC 21386. This bioconversion of heneicomycin is substrate-specific and is not observed using the producer of heneicomycin, Streptomyces filippiniensis NRRL 11044. The three strains show very similar taxonomic characteristics. These results suggest that heneicomycin is a precursor of aurodox, the production of which depends on the bioconversion capability expressed by the strain.

Aurodox↗
PubMed1995

Antibiotic GE37468 A: a novel inhibitor of bacterial protein synthesis. II. Structure elucidation.

GE37468 A is a novel antibiotic produced by Streptomyces sp. ATCC 55365. It has molecular mass 1309.48 and formula C59H52O12N14S5 and belongs to the thiazolyl peptide group of antibiotics. The structure was elucidated by 1H and 13C NMR and MS studies on intact molecule and its hydrolysis products. The antibiotic is a highly modified peptide containing a macrocycle and a side chain composed of a thiazole ring and two dehydroalanine units.

Anti-Bacterial Agents↗
PubMed1995

Antibiotic GE37468 A: a new inhibitor of bacterial protein synthesis. I. Isolation and characterization.

GE37468 A is a new thiazolyl peptide antibiotic obtained by fermentation of Streptomyces sp. strain ATCC 55365. It inhibits bacterial protein synthesis by acting on elongation factor Tu and is structurally and functionally related to the GE2270 class of EF-Tu inhibitors. It is active in vitro against Gram-positive bacteria and Bacteroides fragilis, and protects mice against Staphylococcus aureus infection.

Animals↗
PubMed1994

PAI-1 and factor VII activity are higher in IDDM patients with microalbuminuria.

Microalbuminuria is associated with an increased risk of cardiovascular disease (CVD) in insulin-dependent diabetes mellitus (IDDM) patients, but the pathophysiological basis of this association is not clear. To see whether or not hemostatic dysfunctions might contribute to explain this association, we measured tissue plasminogen activator (t-PA), plasminogen activator inhibitor-1 (PAI-1), factor VII activity, plasma fibrinogen, and plasma endothelin-1 (ET-1) in 13 microalbuminuric (albumin excretion rate [AER], 20-200 micrograms/min) and in 13 comparable normoalbuminuric (< 20 micrograms/min) IDDM patients. t-PA and ET-1 were similar in the two groups, whereas PAI-1 activity (5.65 +/- 1.92 vs. 0.85 +/- 0.58 IU/ml, P < 0.05), factor VII (87.85 +/- 4.94 vs. 76.54 +/- 2.31%, P < 0.05), and plasma fibrinogen (3.38 +/- 0.21 vs. 2.65 +/- 0.13 g/l, P < 0.05) were significantly higher in microalbuminuric than in normoalbuminuric patients. Plasma fibrinogen was related to AER (r2 = 0.23, P < 0.05), whereas triglycerides and factor VII were related to PAI-1 (r2 = 0.39, P < 0.001 and r2 = 0.10, P < 0.05). These results suggest that microalbuminuria is associated with a hypercoagulative and hypofibrinolytic state. Hemostatic dysfunctions might be a pathogenetic link between microalbuminuria and CVD.

Adult↗
PubMed1993

Fibrinolytic imbalance in essential thrombocythemia: role of platelets.

Thrombotic and hemorrhagic complications are frequent in patients with essential thrombocythemia (ET), a myeloproliferative syndrome with an increased number of circulating platelets. Since platelets are a physiological reservoir for the plasminogen activator inhibitor (PAI-1) contained in plasma, we evaluated plasma and platelet tissue plasminogen activator (tPA) and PAI-1 in 20 ET patients with and without thrombotic complications and in 13 control subjects. In ET patients with thrombotic complications there was a significantly greater platelet PAI-1 functional activity than in ET patients without thrombotic complications and in the control group (p < 0.05 and p < 0.025, respectively). Moreover, platelet tPA activity was significantly low in all ET patients (p < 0.001). This fibrinolytic imbalance (increased plasminogen inhibitor and lowered activator) might be a critical cofactor in the thrombotic complications in ET patients.

Adult↗