PubMed Health⌕ Search

Biomedical subjects

C Tozzo

Publications and source records attributed to C Tozzo.

At least 19 recordsLinked to original sources
PubMed2005

Hemodiafiltration with post-dilution reinfusion of the regenerated ultrafiltrate: a new on-line technique.

AIMS: All convective hemodiafiltration techniques require a replacement fluid, which must have an adequate electrolytic composition and must be sterile and pyrogen-free. Using an integrated adsorption cartridge, the ultrafiltrate can be "regenerated" and used as a replacement fluid (hemo-filtrate reinfusion; HFR). The aim of this study was to evaluate whether the HFR technique as suggested in its original configuration could be improved by inverting the purification sequence (post-dilution HFR; PDHFR) in order to increase the purification efficiency of the whole system. METHODS: We performed standard HFR in 6 uremic patients during 6 months and, subsequently, during further 6 months, PDHFR. The dialytic efficacy of the two techniques and the filter blood loss were evaluated. Moreover, we studied how both techniques affected cytokine levels. RESULTS: We observed a significant increase of urea extraction and of Kt/V values in PDHFR. An equally significant improvement was observed in regard to the extraction of beta2-m and the blood loss. Furthermore, IL6 and TNFalpha decreased significantly after PDHFR treatment. CONCLUSIONS: HFR has proven to be an easy-to-perform hemodiafiltration technique, capable of resolving the typical problem of the other hemodiafiltration technique, the availability and production of a sterile and ultrapure reinfusion solution. The inversion of its configuration has allowed us to improve three aspects that have characterized, in our experience, the treatments performed in the original geometry: the removal of both urea and beta2-m, and the filter. Finally, it's notable that the decrease in cytokines levels achieved with PDHFR might attenuate the uremic micro-inflammatory state.

Adult↗
PubMed2004

High sensitivity phonon spectroscopy of Bose-Einstein condensates using matter-wave interference.

We study low-momentum excitations of a Bose-Einstein condensate using a novel matter-wave interference technique. In time-of-flight expansion images we observe strong matter-wave fringe patterns. The fringe visibility is a sensitive spectroscopic probe of in-trap phonons and is explained by use of a Bogoliubov excitation projection method applied to the rescaled order parameter of the expanding condensate. Gross-Pitaevskii simulations agree with the experimental data and confirm the validity of the theoretical interpretation. We show that the high sensitivity of this detection scheme gives access to the quantized quasiparticle regime.

Journal Article↗
PubMed2003

Bragg spectroscopy of the multibranch Bogoliubov spectrum of elongated Bose-Einstein condensates.

We measure the response of an elongated Bose-Einstein condensate to a two-photon Bragg pulse. If the duration of the pulse is long, the total momentum transferred to the condensate exhibits a nontrivial behavior which reflects the structure of the underlying Bogoliubov spectrum. It is thus possible to perform a spectroscopic analysis in which axial phonons with a different number of radial nodes are resolved. The local density approximation is shown to fail in this regime, while the observed data agree well with the results of simulations based on the numerical solution of the Gross-Pitaevskii equation.

Journal Article↗
PubMed1997

Acute renal failure caused by nontraumatic rhabdomyolysis.

Nontraumatic rhabdomyolysis may be associated with severe metabolic disturbances. In particular, previous literature has described a 8-20% incidence of acute renal failure in rhabdomyolysis. The aim of this study was to evaluate our experience on 11 patients with acute renal failure treated by high-efficiency daily hemodialysis.

Acute Kidney Injury↗
PubMed1994

Autologous protein reinfusion in severe ovary hyperstimulation syndrome.

BACKGROUND: Ovarian hyperstimulation syndrome (OHSS) is one of the most serious complications of ovulation induction by exogenous gonadotropins. The pathophysiologic factors of this syndrome are not well known. Increased capillary permeability causes third space fluid shift, which is responsible for ascites, pleural fluid, and edemas. Severe OHSS may result in renal failure, hypovolemic shock, thromboembolic disease, respiratory distress, and may cause death. It has been observed that paracentesis is efficacious, provided that care is taken to reinfuse protein lost in the peritoneal exudate. For this reason, in three patients with severe OHSS we have used a dialytic technique of reinfusion of concentrated ascitic fluid. STUDY DESIGN: We treated three patients with severe OHSS (grade 6). Through sonography-guided paracentesis, the ascitic fluid was concentrated by ultrafiltration and reinfused. This treatment was instituted and performed once only. Ultrafiltration was obtained with a common high-flow dialyzer (polyacrylonitryle membrane). The concentrated fluid was returned to the patient in a peripheral vein. We have limited further treatment to restoration of fluid and electrolyte balance, avoiding in particular potentially teratogenic drugs. RESULTS: In all three patients, a progressive increase of diuresis was evident during treatment and subjective improvement was almost immediate. Fifteen days after treatment, hematologic and biochemical parameters had returned within normal limits. CONCLUSIONS: In treating severe OHSS, we have used the technique of reinfusion of concentrated ascitic fluid to avoid protein depletion induced by paracentesis. We have been able to successfully restore to normal the hematologic and biochemical imbalance with one treatment. Use of the technique described herein should be limited to carefully selected instances and treatment should be performed in an intensive care unit.

Adult↗
PubMed1992

Renal function in patients undergoing cardiopulmonary bypass operations.

We evaluate short- and long-term effects on renal functional reserve of cardiopulmonary bypass in 11 patients. A selected group (persistence of renal functional reserve before operation) of 11 adult patients undergoing cardiopulmonary bypass for aorta-coronary bypass were studied. Renal functional reserve tests were performed in all patients before the operation, at postoperative day 9, and at 6 months after operation. Basal glomerular filtration rate did not show significant changes at 9 days and at 6 months after operation. On the contrary, renal functional reserve was absent at 9 days, but it was restored to preoperative levels at 6 months after operation. In conclusion, our data indicate that cardiopulmonary bypass probably causes renal damage that is not sufficient to influence routine renal function parameters.

Acute Kidney Injury↗
PubMed1992

[Use of ultrafiltration in refractory cardiac decompensation].

Traditional therapy for heart failure (diuretics, digitalic compound, vasodilators, inodilatory ACE-inhibitors) cannot arrest the progressive overloading of the circulatory system so that it is inevitable that a refractory stage to all forms of treatment will be reached when more specialised techniques, such as heart transplant and ultrafiltration will be needed. The paper reports the results obtained in 13 patients in ultrafiltration treatment for refractory heart failure: in the majority of these, a marked improvement in general conditions (edema, dyspnea) was recorded together with a regression from class 5 to class 3 NYHA in 5 patients, and to class 2 for others. The ultrafiltration method in spite of not altering the prognosis which remains negative in these patients, allow those waiting for heart transplant to survive and may improve their chances of surviving heart surgery.

Adult↗
PubMed1992

[Hormonal markers of early-stage osteitis fibrosa in patients on hemodialysis].

The diagnosis of renal osteodystrophy is straightforward when the disease has reached an advanced stage and the pathology is extremely difficult to treat, whereas it is considerably more complex during the early stages. A study was carried out to assess the sensitivity of some biochemical, hormonal and instrumental markers in the early diagnosis of osteitis fibrosa in patients undergoing hemodialysis due to chronic renal insufficiency. Of these markers, the assay of whole molecule PTH appeared to be the most sensitive and specific biological marker.

Adult↗
PubMed1989

Lack of oxidative damage in serum polyunsaturated fatty acids before and after dialysis in chronic uremic patients.

We described previously that in the erythrocytes and mononuclear blood cells from uremic patients on chronic hemodialysis, the membrane concentrations of malonyldialdehyde (MDA), resulting from peroxidation of polyunsaturated fatty acids (PUFA) in the membrane itself increased, and the concentrations of vitamin E (VIT E), the major antioxidizing agent, were lower. In the present study we analysed whether similar oxidative damage is seen in the serum from hemodialysis patients and whether the serum fatty acid pattern is affected. No evidence was found of oxidative damage in the serum during hemodialysis, serum concentrations of MDA and VIT E remaining constant before and after dialysis. No change was observed in serum pattern of PUFA, particularly linoleic acid. We therefore assume that the oxidative damage described in uremic patients is mainly intracellular.

Adult↗
PubMed1988

Discrepancies between serum and erythrocyte concentrations of vitamin E in hemodialysis patients: role of HDL-bound fraction of vitamin E.

Recently, we have demonstrated that hemodialysis (HD) patients have higher serum and lower erythrocyte concentrations of vitamin E than controls. It is known that transfer of vitamin E from serum to erythrocyte is mostly due to high-density lipoproteins (HDL). For a better definition of the pattern of distribution of vitamin E in HD patients, we have dosed the amount of vitamin bound to serum HDL fraction. In 8 patients and in 8 healthy controls, we have determined the concentration of serum erythrocyte and HDL-bound vitamin E. The latest was obtained on an ultracentrifuged HDL fraction. HDL fractions from HD patients have been found to contain larger amounts of vitamin E than controls. The previously described higher serum and lower erythrocyte concentrations of vitamin E in HD patients have been confirmed in the study. The deficit of vitamin E in the membranes of erythrocytes from HD patients has been shown to be the result of increased consumption of the vitamin in the erythrocyte membranes, where it represents the major antioxidant agent. However, the finding of increased amounts of vitamin bound to HDL in HD patients suggests that the transfer of the vitamin to the erythrocyte membranes may also be defective.

Adult↗