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Biomedical subjects

S Zamboni

Publications and source records attributed to S Zamboni.

At least 19 recordsLinked to original sources
PubMed2004

Photomorphogenesis in the hypogeous fungus Tuber borchii: isolation and characterization of Tbwc-1, the homologue of the blue-light photoreceptor of Neurospora crassa.

Truffles form a group of plant-symbiotic Ascomycetes whose hypogeous life cycle is poorly understood. Here we present initial evidence for the influence of light on Tuber borchii mycelial growth and the identification and cloning of a gene, Tbwc-1, homologous to a blue-light photoreceptor of Neurospora crassa. Blue-light irradiation of T. borchii colonies inhibits their apical growth. It also alters apical growth in N. crassa. In Neurospora, the response is controlled by a nuclear photoreceptor, NcWC-1 (White Collar-1), which consists of a sensor domain (LOV) and a transcriptional factor moiety. We isolated a gene (Tbwc-1) whose deduced amino acid sequence shows a high similarity and colinearity of domains with NcWC-1, except for the polyglutamine regions. As previously found in Neurospora, Tbwc-1 mRNA is under light control and its steady state level increases upon irradiation. In silico analysis of the TbWC-1 sensor domain (LOV) supports the hypothesis that TbWC-1 is a photoreceptor, while the absence of the two polyglutamine regions involved in transcriptional activation in Neurospora suggests that this function in Tuber could be lost.

Amino Acid Sequence↗
PubMed2003

Effects of novel manufacturing technology on blood and dialysate flow distribution in a new low flux "alpha Polysulfone" hemodialyzer.

The main target for low flux hemodialyzers is an efficient low molecular weight solutes clearance. Such efficiency is largely dependent on the optimization of diffusion between blood and dialysis solution. The diffusion process can be impaired if there is a mismatch between blood and dialysate flow distribution in the dialyzer. Thus optimized flow distribution both in the blood and dialysate compartment becomes quintessential for the maximal efficiency of the diffusion process within the hemodialyzer. The present paper describes the distribution of the blood and dialysate flows in a new low flux polysulfone hollow fiber hemodialyzer characterized by a specific undulation of the fibers and a new cutting technology of the fibers for an improved micro-flow condition in the blood compartment headers. Twelve Diacap alpha Polysulfone LO PS 15 (1.5 sqm) (B. Braun Medizintechnologie, Melsungen Germany) were employed for the study. Six were analyzed in vitro and six were studied in vivo. Blood flow distribution was studied in vitro by dye injection in the blood compartment during experimental extracorporeal circulation utilizing human blood with hematocrit adjusted at 33%. Sequential images were obtained with a helical scanner in a fixed longitudinal section of the dialyzer 1 cm thick. Average and regional blood flow velocities were measured utilizing the reconstructed imaging sequence. The method allowed the calculation of single fiber blood flow (SF Qb) and the mass transfer zone (MTR) definition in digitally subtracted images. The patterns 20-10 and 40-30 were utilized. The same technology was used to evaluate flow distribution in the dialysate compartment after dye injection in the Hansen's connector. Regional dialysate flow was calculated in central and peripheral sample areas of 1 cm2. Six in vivo hemodialysis treatments on patients with end stage renal disease were performed at three different blood flow rates (250-350 and 450 ml/min) in order to measure urea, creatinine and phosphate clearance. Macroscopic and densitometrical analysis revealed that flow distribution was homogeneous in the blood compartment while in the dialysate compartment a slight difference between the peripheral and central regions in terms of flow velocity was observed. This however was not generating channeling phenomena. Urea creatinine and phosphate clearances were remarkably high and so were the Kt/V observed in all sessions, especially in relation to the studied blood flows. In conclusion, a significant blood to dialysate flow match with optimized countercurrent flow condition was observed in the studied hollow fiber hemodialyzers. Such optimization might be due both to the improved dialyzer design at the level of the blood header and to the specific fiber undulation that prevents dialysate channeling.

Biocompatible Materials↗
PubMed2000

Co-existence of cutaneous T-cell lymphoma and B hairy cell leukemia.

A primary cutaneous form of peripheral T-cell lymphoma (PTCL) and a low grade B-cell non-Hodgkin's lymphoma that was classified as a variant of hairy cell leukemia (HCL) were simultaneously diagnosed in a 79-year-old woman by both phenotypic and genotypic analyses. The coexistence of a T- and B-cell lymphoma in the same patient is rare, and, to our knowledge, this particular association has not been previously described. The patient was referred to our Department for evaluation of multiple cutaneous itchy, reddish plaques; laboratory analyses disclosed a lymphocytosis, that presented 6 years earlier. A bone marrow aspirate showed a 50% B-cell interstitial infiltrate, while a skin biopsy surprisingly revealed a PTCL. Clonality of both neoplastic processes was assessed by Southern blot analysis. The indolent clinical course of the cutaneous disease, and the low and stable number of circulating neoplastic T cells supported the diagnosis of a mycosis fungoides (MF)-like PTCL. Possible oncogenic events and/or putative underlying viral infections which could have played a role in the occurrence of B- and T-cell non-Hodgkin's lymphomas in the same patient are discussed.

Aged↗
PubMed1999

Idiopathic thrombocytopenic purpura treated with steroid therapy does not prevent acute myocardial infarction: a case report.

We report the case of a 65-year-old man affected by idiopathic thrombocytopenic purpura, who developed an acute myocardial infarction after 2 years of steroid therapy. Thrombocytopenia was initially recognized 11 years earlier, and became severe during the past 2 years [platelets (PLTS) 10000-30000/microl]. He was treated with steroids, initially to perform a surgical procedure (prednisone 75 mg/day), subsequently to maintain a platelet count of about 50000/microl (prednisone 12.5 mg/day). After 1 year of treatment, he began to complain about exertional angina and dyspnea. His blood pressure became elevated and cholesterol level raised. The exercise electrocardiogram, previously manifesting ischaemic changes, normalized after 1 month of steroid wash-out; however, steroid therapy was reinstituted (prednisone 5 mg per day). One year later, he suffered an infero-lateral non-Q-wave myocardial infarction. It seems likely that the severe coronary atherosclerosis present in our patient developed despite a low platelet count, under the spur of a heavier risk factor profile. Steroid therapy could have had a role as a precipitating agent of the acute event, and the opportunity of alternative treatments is considered.

Aged↗
PubMed1995

On-line urea monitoring: a further step towards adequate dialysis prescription and delivery.

The aim of this study is to present a clinical experience carried out with a new device designed to measure on-line Urea Nitrogen concentration in the effluent dialysate. The Biostat 1000 Urea Monitor (Baxter Healthcare, Dirfield, Ill, USA) was utilized in the present study. The monitor is based on the principle that multiple urea measurements in the dialysate effluent from the dialyzer, permit to built a double exponential regression leading to the urea kinetic parameters of the dialysis session. Data obtained with the Urea Monitor were, in the present study, compared with those obtained by direct measurements carried out in blood and dialysate and by the collection of the whole amount of spent dialysate. The monitor provided an accurate value of predialysis BUN without any blood drawing. Urea kinetics were established from multiple dialysate measurements and no blood drawing was necessary. The double pool kinetics were taken into account and Kt/V, PCR and SRI% obtained were comparable to those obtained from direct measurement. Since a projected value of Kt/V can be obtained, the monitor could represent a potential source of information to detect possible filter and machine dysfunction, as well as high rate of recirculation.

Adult↗
PubMed1994

Expression and regulation of tumor necrosis factor, interleukin-2, and hematopoietic growth factor receptors in B-cell chronic lymphocytic leukemia.

Leukemic cells from patients with B-cell chronic lymphocytic leukemia (B-CLL) express tumor necrosis factor (TNF) and interleukin-2 (IL-2) receptors, but only a low proliferative response can be elicited in vitro by TNF alpha and IL-2. To investigate the functional properties of IL-2 and TNF alpha on leukemic B cells, we evaluated (1) the regulation of expression of TNF receptors (TNF-R) and IL-2 receptors on leukemic B cells after culture with TNF alpha and IL-2; (2) the effect of the combination of TNF alpha and IL-2 in a proliferative in vitro assay; and (3) the expression and regulation by these cytokines of receptors for hematopoietic factors, including IL-3, granulocyte colony-stimulating factor (G-CSF), and granulocyte-macrophage colony-stimulating factor (GM-CSF). Flow cytometry analysis showed that freshly isolated leukemic cells from B-CLL patients bear the 75-kD TNF-R and the 55-kD IL-2R; TNF alpha was able to upregulate the 55-kD IL-2R but not the 75-kD TNF-R. On the other hand, IL-2 was not able to modify the expression of the above-mentioned receptors. Although each cytokine alone was unable to induce a relevant proliferation of leukemic cells, a synergistic proliferative effect was detected when these cytokines were used in combination. Leukemic B cells from B-CLL patients bear receptors for hematopoietic factors (IL-3, G-CSF, and GM-CSF) that were upregulated in vitro by IL-2 via the 55-kD IL-2R. On the contrary, TNF alpha was unable to affect the expression of the above-mentioned receptors. These results indicate (1) that IL-2 and TNF receptors are related to each other on leukemic cells in B-CLL and (2) that the IL-2R is involved in the regulation of other structures, ie, CSF receptors, thus pointing to another functional role of this receptor complex and the related cytokine in leukemic cells.

Aged↗
PubMed1992

[Heart failure in the population: prevalence data].

We report on the prevalence of chronic heart failure (CHF) in a random sample of a population (aged 20-64 years) from the Veneto region in northern Italy. The relationship between CHF and hypertension and obesity was also investigated. These data were collected during an international research project coordinated by the World Health Organization. The overall prevalence of CHF was 2.0% both in the male and female population. The prevalence of CHF increased significantly with age and was positively correlated with body mass index in both sexes. Patients with borderline hypertension showed a 3.5-fold increased prevalence of CHF. The prevalence of CHF was 4.9-fold higher in hypertensive than in the normotensive subjects. Patients treated with hypotensive drugs had a significantly higher prevalence of CHF than untreated patients.

Adult↗
PubMed1991

INTERSALT in Italy: findings and community health implications.

In INTERSALT, an international cooperative study on electrolytes and blood pressure, significant associations were found, in the pooled data for 52 centres, between systolic BP and sodium (Na) excretion, body mass index (BMI), high alcohol intake and low potassium (K) excretion. We have assessed the status of the four Italian centres (Mirano, Gubbio, Bassiano, Naples) on these variables. The four centres examined a total of 794 men and women aged 20-59 years. Combined values were similar to overall INTERSALT levels for daily Na excretion (170 mmol) and BMI (25 kg/m2). The Italian centres had slightly higher potassium excretions (57 vs. 55 mmol/day), a higher prevalence of drinkers and a greater average alcohol consumption. Participants were divided into those below or above median levels of Na, K, BMI, and by alcohol intake (below or above 300 ml/week). Both systolic BP and diastolic BP were found to be lower in the more favourable stratum, for each variable. When all four factors were combined, those below median Na excretion and BMI, above median K, and with alcohol intake less than 300 ml/week had age-adjusted systolic BP 7.5 mmHg lower than those with less favourable levels of all four variables. The difference in adjusted diastolic BP was 4.3 mmHg. The data indicate the potential for lower population average BP with improved lifestyles.

Alcohol Drinking↗
PubMed1990

Clinical trials for the reduction of coronary artery disease: a critical review.

Our present knowledge about risk factors and cardiovascular events has a solid foundation in epidemiological studies. However, if it is clear that the link between risk factors and events is represented by the pathogenetic role that hypertension, hypercholesterolaemia and cigarette-smoking have in arterial atherosclerotic disease, we still do not know whether these risk factors contribute to the progression from silent atherosclerosis to atherosclerotic events. This may explain some of the difficulties we have in interpreting the results of primary prevention trials. The anatomical regression of atherosclerotic plaques obtained by treating risk factors could be the clue to a better understanding of the clinical phenomena.

Adult↗