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Biomedical subjects

R Chiavarelli

Publications and source records attributed to R Chiavarelli.

32 records · Page 2Linked to original sources
PubMed1982

Effects of cardioplegic solutions on conductive coronary arteries.

The effects of two cardioplegic solutions (CPSs) on isolated, superfused, bovine coronary arteries were compared with those produced by changes in composition of standard Krebs medium. High potassium, low sodium content or the addition of albumin produced vasoconstriction; high magnesium, high glucose content or the addition of mannitol led to vasodilatation. In most cases hypothermia slightly reduced vasoconstriction and enhanced vasodilatation. The action of the two CPSs is the result of the interaction of these basic effects. The results suggest that the vasomotor reactions of coronary arteries to CPS may affect the delivery of the CPS to the myocardium and exert a critical influence on successful cardioplegia.

Animals↗
PubMed1982

The central-nervous-system toxicity of long-term oral administration of L-tryptophan to porto-caval-shunted rats.

In a previous paper we have reported that the oral long-term administration of 200 mg/kd of L-tryptophan to rats with a porto-caval shunt causes significant loss of body weight, muscular hypertonicity and aggressivity, as well as marked alteration of the liver structure. We now report that tryptophan administered at the same dosage for the same length of time also induces significant alteration of the central nervous system. These results further demonstrate that high plasma levels of tryptophan are quite well tolerated by control animals but are quite toxic to rats with a porto-caval shunt. We also claim that the brain alterations observed in such animals are not secondary to liver dysfunction but to high levels of plasma tryptophan per se.

Animals↗
PubMed1982

[Value of a rational postoperative treatment protocol in cardiac surgery].

The postoperative course of 76 patients, who underwent valve and/or coronary surgery during a period of 18 months, was analyzed to determine the influence of the overall non-surgical management on the results of the operations. We used an approach (System analysis) based upon analysis of the cardiac, pulmonary, renal, general metabolic, neurologic, and gastrointestinal subsystems. The use of inotropic support and the incidence of postoperative arrhythmias were lower. The permanence in intensive care unit and the hospital postoperative course were shorter in comparison with all series of patients who had the same type of surgery over the same period in our unit. These results indicate that the postoperative care after cardiac surgery needs accurate analysis, precise deductions and effective treatment.

Cardiac Surgical Procedures↗
PubMed1981

[Hyperbaric oxygenation in cerebral air embolism occurring during open-heart surgery (author's transl)].

Hyperbaric oxygenation was used in two patients with extensive neurologic damage from cerebral air embolism occurring during open-heart surgery. One patient made a full recovery. The use of hyperbaric oxygenation produces the most direct relief of the mechanical obstruction and provides the definitive treatment for cerebral air embolism. First consideration must be given to the prevention of this complication, but once an embolus has occurred, hyperbaric treatment should be instituted promptly and early. Therefore every team engaged in open-heart operations should be familiar with the diagnosis and the therapy of air embolism.

Cardiac Surgical Procedures↗
PubMed1980

Behavioral, electroencephalographic, and biochemical changes in porta-cava shunted rats.

Behavioral, electroencephalographic, and biochemical alterations have been studied in rats with porta-caval shunt, up to 45--50 days after the operation. No behavioral or electroencephalographic changes have been observed, while modifications of various amino acids both in plasma and brain have been found. Among all the amino acids considered of particular significance are the plasma and brain increases of tyrosine, phenylalanine, and tryptophan, since they are the precursors of biogenic amines. In fact, the increase of 5-HIAA found in regions of CNS which are richest in serotoninergic synapsis could indicate an increased turnover of 5-HT. On the other hand no significant alterations of turnover of catecholamines have been found.

Acetates↗
PubMed1980

[The optimal time for surgical correction of coarctation of the arota (author's transl)].

A survey of the literature on coren. Operative mortality was reduced from 39% (1960 through 1970) to 26% (1971 through 1978). It was higher in patients operated on during the first three months of life and in those with associated cardiac lesions. The incidence rate of restenosis has diminished from 27% to 4% by using the aortoplasty with a subclavian flap. Since the natural and the "innatural" history emphasize the importance of early diagnosis and treatment for patients with coarctation of the aorta, these recent results suggest that the optimal time for elective surgical correction is around the age of one year, and that the subclavian flap procedure is the technique of choice at this age.

Age Factors↗
PubMed1979

The toxic effects of long-term, oral administration of L-tryptophan in rats with portacaval shunt.

The oral, long-term administration of 200 mg/kg of L-tryptophan to rats previously submitted to a portacaval shunt causes significant loss of body weight, muscular hypertonicity and aggressivity, as well as marked alterations of the liver structure. Conversely, the same treatment is well tolerated by control animals. It is postulated that the derangement of tryptophan metabolism normally occurring in rats with portacaval shunt is by itself insufficient to induce behavioural changes and liver damage, which, on the contrary, develop when tryptophan metabolism is further altered by the administration of the amino acid to the animals for a long period of time.

Animals↗
PubMedDate not supplied

Efficiency of different hollow-fiber hemofilters in continuous arteriovenous hemodiafiltration.

Low dialysate to blood flow rate ratios are a unique characteristic of continuous arteriovenous hemodiafiltration (CAVHDF) that should allow complete saturation of dialysis fluid with small-molecular-weight blood solutes. The aim of the investigation was to evaluate the performance of different hemofilters in CAVHDF. In 10 critically ill patients with acute renal failure, the efficiency of four hollow-fiber hemofilters, polyamide 0.6 m(2), polyacrylonitrile (PAN) 0.3 and 0.6 m(2), acrylonitrile sodium methallylsulfonate (AN69HF) 0.6 m(2), has been evaluated. For comparison, dialysate flow rates (Q(di)) were standardized to 16.6 and 25 ml/min. Samples for urea nitrogen were obtained from the arterial blood line (C(bi)) and from the dialysate exit port (C(do)) within 24-hour running time. Outflowing dialysate (Q(do)) was also measured at the same time. Blood flow (Q(b)) was calculated by the bubble transit time technique. Diffusive and total urea clearances were determined. AN69HF and PAN hemofilters provided higher clearances than the polyamide hemofilter. Despite the smaller surface area, PAN 0.3 m(2) had a total urea clearance comparable to that of PAN 0.6 m(2) and AN69HF at Q(di) = 16.6 ml/min. While at Q(di) = 16.6 ml/min equilibrium between blood and dialysate (C(do)/C(bi) congruent with 1) occurred with the AN69HF and PAN hemofilters, at Q(di) = 25 ml/min the equilibrium was obtained only with the AN69HF hemofilter. In conclusion, almost complete urea saturation of dialysis fluid has not been obtained with all hemofilters tested here. In our experience, membrane characteristics play an important role in determining diffusive efficiency in CAVHDF.

Acrylic Resins↗
PubMedDate not supplied

[EEG and biochemical considerations on 40 cirrhotic patients surgically treated by portacaval anastomosis or mesenterico-caval bypass].

Starting from biochemical hypotheses on hepatic encephalopathy, which presuppose at the basis of this disease first of all some modifications of the plasmatic values of octopamine, ammonia, serotonin and of particular aromatic aminoacids, the Authors compared the levels of ammoniemia and of octopaminemia with eegraphic data, in two groups of cirrhotic patients, operated of porto-cava anastomosis (16 patients) ad of mesenterico-cava by-pass (24 patients). All this in order to value if there are significant correlations between these values and the cerebral damage and also if there are differences between the two types of operation. Attained data show a good correlation between neuropsychiatric symptomatology and importance of the cerebral damage noticeable at the E.E.G. As to the possible correlations existing between biochemical data and E.E.G., while as to plasmatic octopamine no significant modifications were found, as to ammoniemia, highest values correspond to findings of greater cerebral compromission. Moreover, it seems that between the two types of operations, the mesenterico-cava by-pass is the one that allows a better clinical and eegraphic evolution.

Amino Acids↗
PubMedDate not supplied

[Weaning in cardiopulmonary bypass patients with compromised cardiac function. Comparison of enoximone and dopamine].

OBJECTIVE: Evaluate the effects of enoximone and dopamine in patients with impaired left ventricular function after cardiopulmonary bypass (CPB). DESIGN: Prospective study on a consecutive series of patients subdivided into two groups: enoximone (Group E) and dopamine (Group D). SETTING: Policlinico Umberto I, University La Sapienza of Rome. PATIENTS AND METHODS: Thirty patients undergoing elective myocardial revascularization. Before weaning from CPB the patients received inotropic drugs as follows: Group E: enoximone: bolus: 1 mg/kg in 10 min, and continuous infusion of 5 mcg/kg/min; Gruppo D: dopamine: continuous infusion of 5 mcg/kg/min. Hemodynamic measurements were made using a Swan-Ganz catheter inserted before the induction of anaesthesia. RESULTS: Enoximone has proved to be effective in decreasing pre-load and after-load of both right and left ventricle by a positive lusitropic effect and a reduction of systolic stress, thereby increasing the cardiac index. In group D patients maintenance of cardiac output has been demonstrated to be dependent on a chronotropic effect. As a consequence in group D the increase in rate-pressure product has reached potentially dangerous values, reflecting a marked increase in myocardial oxygen consumption. On the contrary in Group E the increase in rate-pressure product has been much more limited. Finally both drugs have proven effective, since all patients have been easily weaned from CPB. CONCLUSIONS: Enoximone is a useful and easily-handled drug to facilitate weaning from CPB of patients with preoperative impaired ventricular function.

Assisted Circulation↗