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Biomedical subjects

A Rosati

Publications and source records attributed to A Rosati.

At least 55 records · Page 3Linked to original sources
PubMed1996

Hyperparathyroidism: is it really the major factor affecting glucose tolerance in uremia?

The effects of secondary hyperparathyroidism (sHPTH) on immunoreactive insulin (IRI) release and glucose (G) tolerance were studied in two groups of dialysis patients with normal (NPTH, n = 9) or elevated PTH levels (HPTH, n = 8), 27 +/- 24 and 660 +/- 440 pg/ml, respectively. The patients received an intravenous glucose tolerance test (IVGTT) using 0.33 g/kg of glucose solution. G, IRI and C-peptide (C-p) levels were determined calculating the G constant decay (K) and the relative incremental areas for each study. Regardless of PTH levels, all patients showed an impaired glucose tolerance (GT). IRI secretion and K values were not significantly different between the two groups. However, a significantly lower K value with a reduced (although not significant) early and late IRI secretion was found in the subgroup of patients with more severe. sHPTH (PTH: 560-1,500 pg/ml, n = 5) as compared to patients with moderate sHPTH (PTH: 87-341 pg/ml, n = 4) or normal (5-32 pg/ml, n = 8) PTH levels. No relationship was found between PTH and G, IRI or C-p levels. Our results point to a threshold limit for PTH's inhibitory effect on IRI secretion and suggest that other factors, known to affect IRI secretion and GT besides PTH levels, may modulate the role played by excess PTH levels on carbohydrate metabolism of dialysis patients.

Adult↗
PubMed1996

Ethylene-oxide and steam-sterilised polysulfone membrane in dialysis patients with eosinophilia.

Eosinophilia and some acute dialysis side-effects, such as itching, flushing and bronchospasm, are often associated with the presence of ethylene oxide (ETO) as dialyzer sterilizing agent. This study evaluated the effects of two different polysulfone (PS) hollow-fiber dialysers sterilized with ETO and steam in 31 chronic dialysis patients with eosinophilia. Clinical symptoms, metabolic and biochemical parameters, complement (C3a and C5a) activation and production were evaluated in each patient dialysed for two months at a time with Cuprophan dialyser, ETO-PS dialyser and steam-PS dialyser. The steam-sterilizer agent does not alter the purifying capacity of the PS membrane which maintains its superiority over Cuprophan in terms of biocompatibility. Using steam-PS, intradialytic eosinophil kinetics seems to improve. In some patients with high serum levels of ETO-specific IgE these levels tend to diminish. Generic intradialytic symptoms do not differ between the two sterilization methods, although some hypersensitivity symptoms during the first dialysis hour are considerably lower in some patients when steam-sterilized PS is used.

Adult↗
PubMed1996

Zinc and cadmium ions differently modulates A1 adenosine receptors.

The results suggest that: 1) Zinc ions may chelate the histidines critical for the agonist binding preventing hydrogen bonds between nonprotonated nitrogen atom of His-251 and the exocyclic N6-H in CHA or CCPA molecule and between His-278 and -OH of the ribose ring. This mechanism can explain the reduction in the number of binding sites without changing the affinity. 2) Cadmium ions may oxidize cysteine SH-groups. The redox reaction between Cd2+ and receptor thiols may result in binding of the metal into stable (di)thiol-cadmium complexes rather than in the formation of disulfide and liberation of the reduced metal. This mechanism can justify the conformational modifications of the receptor molecule producing the decrease in affinity.

Animals↗
PubMed1989

In vivo ESR dosimetry in total body irradiation.

Total body irradiation (TBI) using high doses (about 10 Gy) with photons in the range between 1 and 10 MV combined with intensive chemotherapy has been used successfully in treatment of acute and chronic leukemia before bone marrow transplantation. One of the principal international guidelines in TBI is to use in vivo dosimetry in order to compare the prescribed dose with that absorbed. The use of in vivo dosimetry is also useful as a retrospective evaluation of any deviation from the prescribed dose greater than +/- 5% for relevant parts of the body, especially in the lung and in other organs at risk. In this paper, Electron Spin Resonance (ESR), using alanine dosimeters, is demonstrated to be a powerful tool for absorbed dose evaluation in TBI by detection of free radicals produced in alanine by ionizing radiation. In this study, we present the results obtained using ESR dosimetry in eleven patients undergoing TBI. The major advantages appear to be: 1. the ESR signal in alanine dosimetry is stable for years without fading: 2. the detection of the ESR signal does not destroy the information and so enables a retrospective judgment of the TBI plan adopted.

Alanine↗
PubMed1987

A survey of radiation dose and image quality in mammography: an ongoing program in Italy.

A program for mammography optimization in individual x-ray units, named Dose and Quality in Mammography (DQM), is now underway in Italy. The project has three stages: measurement of the parameters that affect dose and image quality by means of devices that are practical to use (specifically designed for the purpose), analysis of data to evaluate dose and image quality and suggestion of possible improvements to each unit operator. Instruments and methods employed in our survey are described. Our results, like those of the American survey (Je78) Breast Exposure: Nationwide Trends (BENT), show widespread variations of exposure, half value layer (HVL), optical density, dose and resolution. Facilities using the same type of x-ray apparatus (Mo target-Mo filter) and film-screen combinations present very different exposure values, ranging from 1.6 X 10(-4) to 27.6 X 10(-4) C kg-1. The causes of these variations--ascribable to the individual units, radiologist preferences, processing condition, kVp indicator and timer accuracy--are being explored.

Italy↗
PubMed1981

Electron paramagnetic resonance study of storage effects on ceruloplasmin in human serum compared with purified ceruloplasmin in aqueous solution.

The EPR signal amplitude of human serum ceruloplasmin shows significant changes as a function of time and temperature during storage. The same behavior occurs with aqueous solutions of purified ceruloplasmin. From the observation that the spectral lines of the EPR signal of ceruloplasmin from unmanipulated serum are identical to those coming from purified ceruloplasmin, we conclude that only type I Cu2+ of ceruloplasmin are involved in the signal changes. A temperature-dependent electron shift toward type I Cu2+ paramagnetic centers, occurring via the type II and type III Cu2+ species of the protein, is believed responsible for the process. The possible origin of the reducing electrons is discussed. A procedure to obtain reproducibility of recording of EPR spectra of ceruloplasmin in physiological fluids is proposed.

Blood↗
PubMedDate not supplied

Donor characteristics can influence transplant activities and the access to transplant for some age groups.

In recent years Italy has experienced a remarkable increase in organ donation and transplant rates for kidney transplantation. The organ donation rate has placed Italy among the European leaders, but a careful comparative evaluation of Italian and international registries data demonstrates that renal transplantations have not shared the same significant growth. In a decisive way donor characteristics have influenced not only the number of renal transplantations, but also the access to transplant for some age groups. We investigated the probability of transplantation from different age groups using the Kaplan-Meier method and the log-rank test. The 7-year probability of transplant was 72% for the 15 to 45 age group, 85.7% for the 46 to 55 age group, and 88.5% for the over 55 years group (P = .0029). Ethical considerations suggest new approaches of innovative promotion of living donor transplants and a revision of organ allocation criteria.

Adolescent↗