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C Rossetti

Publications and source records attributed to C Rossetti.

At least 73 records · Page 4Linked to original sources
PubMed1987

The nature of the neutral Na+-Cl(-)-coupled entry at the apical membrane of rabbit gallbladder epithelium: II. Na+-Cl- symport is independent of K+.

In the epithelium of rabbit gallbladder, in the nominal absence of bicarbonate, intracellular Cl- activity is about 25 mM, about 4 times higher than intracellular Cl- activity at the electrochemical equilibrium. It is essentially not affected by 10(-4) M acetazolamide and 10(-4) M 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonate (SITS) even during prolonged exposures: it falls to the equilibrium value by removal of Na+ from the lumen without significant changes of the apical membrane potential difference. Both intracellular Cl- and Na+ activities are decreased by luminal treatment with 25 mM SCN-; the initial rates of change are not significantly different. In addition, the initial rates of change of intracellular Cl- activity are not significantly different upon Na+ or Cl- entry block by the appropriate reduction of the concentration of either ion in the luminal solution. Luminal K+ removal or 10(-5) M bumetanide do not affect intracellular Cl- and Na+ activities or Cl- influx through the apical membrane. It is concluded that in the absence of bicarbonate NaCl entry is entirely due to a Na+-Cl- symport on a single carrier which, at least under the conditions tested, does not cotransport K+.

Animals↗
PubMed1986

Intracellular potassium as a possible inducer of amino acid transport across hamster jejunal enterocytes.

Brush border membrane potentials (Vm), intracellular K+ activity (aiK) and alanine uptake were measured in different parts of villi in mid-jejunal tissue taken from hamsters fed different amounts of food at high and low environmental temperatures. Basal villus enterocytes (Y cells) were found to have lower values for Vm and aiK than upper villus enterocytes (O cells). Alanine uptake was confined to O cells. The position on the villus where values for Vm and aiK changed, and where alanine uptake could first be seen to take place, depended on the energy intake and environmental temperature at which hamsters were kept. Na+-dependent alanine uptake and Vm were both higher in O cells of hamsters fed 10 kcal day-1 at 30 degrees C (10 k/30 degrees C) compared with animals fed 30 kcal day-1 at an environmental temperature of 12 degrees C (30 k/12 degrees C hamsters). The rates at which enterocytes migrated along the crypt-villus axis, measured separately in thymidine-labelling experiments, were 6.9 and 16.1 micron h-1 for 10 k/30 degrees C and 30 k/12 degrees C hamsters respectively. Both Vm and aiK were estimated, from these measurements, to have increased significantly by the time enterocytes became 30 h old. Alanine uptake began 15 h later. Neither of these parameters were influenced by previous adaptation conditions. The close temporal and variable positional relationship found between changes in aiK and onset of transport suggests that early changes in electrolyte composition might initiate a second phase of development enabling the enterocyte to absorb nutrients. The possibility that other ions besides K+ might also be involved in this aspect of regulation is also discussed.

Alanine↗
PubMed1985

Construction of K+- and Na+-sensitive theta-microelectrodes with fine tips: an easy method with high yield.

A new method is described to prepare theta-microelectrodes with tips up to 0.15 micron diameter controlled under scanning electron microscope. K+- and Na+-sensitive resins were tested. Method features are the following: i) hard drying of the glass, ii) rehydration of one channel and weak wetting of the other with a three-methylchlorosilane solution before pulling, iii) simultaneous presence of water and silane in the two channels during pulling, iv) gradual silanization from the tip to the shank. Selective and conventional channels did not affect each other and no displacements of resins were observed. The change of potential difference of the selective channel was more than -50 mV/decade. Apical membrane potentials and cell Na+ and K+ activities of the epithelial cells of rabbit gall-bladder (cell diameter: 5-10 micron) were measured with these theta-microelectrodes and with single-barrel microelectrodes of similar tip size: results obtained were not significantly different.

Animals↗
PubMed1984

Developmental changes in intra-enterocyte cation activities in hamster terminal ileum.

Intracellular Na+ and K+ activities have been determined under visual control in enterocytes located at known positions along hamster ileal villi in vitro. The intracellular K+ activity found in enterocytes migrating over the basal third of villi was significantly less than that found in older enterocytes (83 and 113 mM respectively). The intracellular Na+ activity remained unaffected by the state of enterocyte development (32 mM throughout). Extracellular K+ and Na+ activities measured close to the luminal surface of the intestine were always similar to those measured in the bulk of the bathing medium. There was, however, a small difference in K+ activity detected between the bulk solution and solution near the luminal surface of enterocytes (3 . 4 and 3 . 6-3 . 7 mM respectively). Na+ activity in the villus core was also similar to that of the bathing medium. The brush border membrane content of sucrase-isomaltase, determined cytochemically, was found to increase rapidly as enterocytes migrated over the basal third of the villus and to plateau at a point roughly equivalent to that where intracellular K+ activities became maximal. The numerous ways by which enterocytes might control their intracellular K+ concentrations during development are emphasized. Attention is nevertheless drawn to the close correspondence seen between different aspects of brush border membrane development and the ability of enterocytes to maintain high internal concentrations of K+.

Animals↗
PubMed1983

Bicarbonate effects, electromotive forces and potassium effluxes in rabbit and guinea-pig gall-bladder.

The stimulating effect of external HCO3- on Na+ salt transport has been examined in rabbit and guinea-pig gall-bladder by electrophysiological methods, as a sequel to a previous study carried out by radiochemical techniques. At steady state, cell K+ activity was found to be significantly reduced in the presence of HCO3-, whereas cell Na+ activity significantly increased; in parallel the apical membrane p.d. was depolarized; K+ equilibrium potential was higher than membrane p.d. in every case. The apical p.d. dependence on K+ was unaffected by HCO3-, but in the guinea-pig it was affected by Cl-. Rapid increases in HCO3- concentration on the luminal side caused a depolarization of the apical p.d. of the guinea-pig within about 30 sec, an effect that did not occur if the tissue was pre-treated with 10(-4) M-acetazolamide; the epithelial resistance and apical/basolateral resistance ratio were unchanged in all cases. The primary action of HCO3- is confirmed to be on the apical membrane; an HCO3- conductance does not seem to be present at this level, either in the rabbit or guinea-pig, nor does HCO3- affect Na+ influx through the apical conductive pathway, so that all the stimulating effects of the anion are confirmed to be on the neutral transports of Na+ salts; in spite of this, the apical electromotive force is modified due to the changed cell K+ activity. The rapid depolarization caused by the anion in the guinea-pig is in agreement with an HCO3- electrogenic secretion and/or a basolateral conductance for the anion. Polyelectrolyte dissociation from protons increases in the absence of external HCO3-: the negative charges are mainly counterbalanced by bound Na+ in the rabbit and by free K+ in the guinea-pig. K+ leakage from the cell into the lumen is calculated to be minimal in the rabbit and all K+ lost could be reabsorbed through the paracellular pathways; K+ efflux to the subepithelial layer via conductive routes is insufficient to account for the over-all K+ efflux.

Animals↗
PubMedDate not supplied

Causes of death and postsurgical survival in familial adenomatous polyposis: results from the Italian Registry. Italian Registry of Familial Polyposis Writing Committee.

Causes of death were evaluated among 350 deceased patients with familial adenomatous polyposis (FAP) recorded in the Italian Polyposis Registry: 78.1% were due to colorectal cancer, 9.5% to extracolonic cancer (more than half of the upper gastrointestinal tract), 3.6% to desmoid tumors, and 8.8% to other causes. The age at diagnosis among 604 patients was studied in relation to presence of symptoms at presentation and presence of colonic cancer at surgery. In asymptomatic patients younger than 30 years the risk of colonic cancer was 3.3% and in symptomatic patients older than 40 it was 80%. A life-table analysis showed that postsurgical survival among patients without cancer at colectomy was 68% after 30 years, whereas that of patients with cancer was 41% after 10 years. The alternative prophylactic treatments of total colectomy with ileorectal anastomosis versus total proctocolectomy (IRA vs. IAA) were compared in terms of postsurgical survival. Both treatments showed a survival of 83% after 10 years. The risk of cancer in the rectal stump after IRA was 14.5% after 15 years and 25.2% after 25 years; the corresponding risks of dying from it were 4.3% and 9.3%, respectively.

Adenomatous Polyposis Coli↗
PubMedDate not supplied

Correlation of SPECT and PET cardiac images by a surface matching registration technique.

Complementary information provided by Single Photon and Positron Emission Tomography (SPECT and PET) in nuclear cardiology allows a better comprehension of the physiopathology of the heart. In this work a surface matching registration technique is evaluated in the spatial correlation of SPECT and PET cardiac images. The method is based on matching correspondent anatomical surfaces extracted from transmission (TR) SPECT and PET studies, usually performed for attenuation correction. The accuracy of the technique was evaluated by phantom experiments and on patient data (201Tl SPECT and 13NH3 PET perfusion studies). An application of the method is presented for the correlation of SPECT 201Tl perfusion and PET 18FDG metabolic studies in the evaluation of myocardial viability.

Ammonia↗
PubMedDate not supplied

Clinical aspects and management of hereditary non-polyposis colorectal cancer (HNPCC).

Hereditary non-polyposis colorectal cancer (HNPCC) is an autosomical dominant trasmitted disease phenotypically defined according to the "Amsterdam criteria" as follows: at least 3 affected relatives, one of whom first degree relative of other two, at least two successive generations affected. Important cardinal features are: 1) prevalent proximal location of cancers (above splenic flexure); 2) multiple synchronous or methachronous large bowel cancers; 3) early age of onset (<50 years); 4) presence of extracolonic cancers (endometrium, stomach, urinary tract, skin). The treatment is essentially surgical and total colectomy with ileo-rectum anastomosis is already proposed as standard procedure with annual endoscopic examination of retained rectum. The screening of individuals at risk, so determined by the analysis of pedigree or the results of molecular tests, must be performed every 1-2 years by colonoscopy starting around the age of 25 years. In this review are described and analysed the spectrum of the disease with particular attention to the frequency and characteristics of extracolonic cancers. Moreover, the guidelines of the surveillance and screening are reported following the data of the literature and as proposed by the International Collaborative Group (ICG-HNPCC).

Age of Onset↗
PubMedDate not supplied

Different expressivity of two adjacent mutations of the APC gene.

AIMS AND BACKGROUND: The phenotypic expression of different APC mutations in familial adenomatous polyposis (FAP) is variable: two to three variants of the disease have been defined based on the severity of colonic manifestations. Age of onset and number of polypectomies per person-year of post-surgical follow-up were compared in two FAP families with very close mutation sites in the APC gene, in order to ascertain mutation-specific variation of expressivity. FAMILIES AND APC MUTATIONS: Family A (5 patients) carried a newly characterized mutation, a four bp deletion at codon 843. Family B (5 patients) carried a previously identified mutation at codon 835. RESULTS: Mean age of onset was 49.7 years in family A and 30.5 years in family B; number of polypectomies per person-year of follow-up was 1.05 for family A and 10.1 for family B (P < 0.001). CONCLUSIONS: There is significant variation of expressivity (allelic heterogeneity) in FAP between two mutations separated by only eight codons, located at the 5' extremity of APC gene exon 15.

Adenomatous Polyposis Coli↗
PubMedDate not supplied

Patient survival and cardiovascular events after kidney-pancreas transplantation: comparison with kidney transplantation alone in uremic IDDM patients.

In diabetic patients cardiovascular morbidity and mortality is still a major problem. Our aim was to study the effect of kidney-pancreas transplantation on survival, cardiovascular events, and causes of death in diabetic type 1 uremic patients. Three hundred and thirty-three uremic IDDM patients were enrolled in our waiting list for kidney-pancreas transplantation: 107 underwent kidney-pancreas transplantation (KP), 34 underwent kidney transplantation alone (KA), whereas 192 patients remained on dialysis (WL). Actuarial survival and causes of death were recorded over a period of 7 years. Seven-year survival rate was 75% for the KP group, 63% for the KA group, and 37% for the WL group (p = 0.001). Cardiovascular death rate was 9.8% in the KP group, 17.6% in the KA group, and 18.1% in the WL group (KP vs. WL, p = 0.05). Rate of acute myocardial infarction in the KP group was lower than in the KA group (2.4% vs. 17.6%, p = 0.005) as well as rate of acute pulmonary edema (0.8% vs. 23.5%, p = 0.0001) and rate of hypertensive patients at 1 (40.9% vs. 85.0%, p = 0.0001) and at 2 years (57.6% vs. 80%, p = 0.03). Kidney-pancreas transplant helped to obtain euglycemia with positive effects on survival and cardiovascular events.

Adult↗
PubMedDate not supplied

Positron emission tomography for the assessment of myocardial viability: a synopsis of methods and indications.

An improvement of regional and global left ventricle dysfunction can be achieved in patients with coronary artery disease either by coronary revascularization with percutaneous transluminal coronary angioplasty or coronary artery bypass grafting. Several techniques have been developed to identify dysfunctional but viable myocardium. In the last decade, positron emission tomography (PET) with 18F-fluorodeoxyglucose (18F-FDG) has been used for the detection of hibernating myocardium. It can accurately predict the recovery of abnormal wall motion in hibernating segments prior to surgery. In particular, assessment of viability with 18F-FDG is indicated in high-risk surgical candidates being considered for revascularization or transplantation. Moreover, patient selection criteria and economic consideration are also relevant for cost-effective use of the technique.

Angioplasty, Balloon, Coronary↗
PubMedDate not supplied

[Correction measured by attenuation in tomographic heart studies with single photon emission with thallium 201. Comparison with positron- emission tomographic studies with ammonium marked with nitrogen].

PURPOSE: We investigated 201Tl myocardial uptake with(out) nonuniform attenuation compensation in ischemic myocardiopathy patients. The segmental patterns of the two types of SPECT images were compared with PET [13N]NH3 studies performed in the same patient. PET images were taken as reference and the diagnostic accuracy of SPECT with(out) attenuation correction was evaluated. MATERIAL AND METHODS: During the SPECT study transmission and emission data were simultaneously recorded by a triple head gamma camera equipped with fan beam collimators and a 99mTc transmission line source (740MBq). SPECT and PET images, the former reconstructed with(out) attenuation correction, were corecorded and reoriented along the short axis. The left ventricular wall was divided into 11 segments and segmental activity normalized to maximum in each study. RESULTS: Statistically significant differences were found between PET/(un)corrected SPECT ratios in posterior and septal segments. In these myocardial regions, attenuation correction compensates for attenuation artifacts, by correcting the underestimation of radioactivity concentration caused by radiation absorption. A statistically significant difference was also found in midventricular anterior and apical segments (p < .05). However, in these regions attenuation correction results in a decrease in corrected relative to uncorrected SPECT activity. The agreement rate with PET data is higher for corrected SPECT (mean differences were 3.12 +/- 11.51 and 2.19 +/- 8.63 for uncorrected versus corrected SPET). We had 50% positive and 77% negative predictive value without attenuation correction, versus up to 69% and 90%, respectively, with attenuation correction. CONCLUSIONS: The attenuation correction procedure with simultaneous transmission-emission effectively reduces attenuation artifacts in SPECT myocardial imaging. While diagnostic accuracy increases in posterior and septal myocardial regions, anterior and apical data need careful interpretation because a relative decrease in radioactivity concentration can be observed after attenuation correction.

Adult↗
PubMedDate not supplied

Prognostic factors in colorectal cancer.

Prognostic factors should always be taken into consideration before planning treatment. As reported in the literature, and also in our experience, the extent of intestinal wall invasion and the lymph node status must be considered the most important prognostic factors. In the present paper the data from literature are reported and the impact of biologic factors is analyzed. We are convinced that in the future the biological factors of the tumor as well as of the patient should be considered in planning treatment.

Biomarkers, Tumor↗