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Biomedical subjects

R Calvo

Publications and source records attributed to R Calvo.

134 records · Page 8Linked to original sources
PubMedDate not supplied

Plasma protein binding of etomidate in patients with renal failure or hepatic cirrhosis.

The influence of renal failure and of hepatic cirrhosis on the plasma protein binding of etomidate, an intravenous anaesthetic agent of basic nature, has been investigated. The percentage of free etomidate in plasma containing 1 microgram/ml was markedly increased in patients with renal failure and in patients with hepatic cirrhosis, when compared with a group of healthy volunteers (43.4 +/- 2.9% and 44.2 +/- 2.1 versus 24.9 +/- 1.4%). This decrease in binding correlated inversely with serum albumin levels in both conditions (r = -0.88 and r = 0.72, respectively) but a slight decrease in the amount bound per mole of albumin was also apparent in both types of disease.

Adult↗
PubMedDate not supplied

[Characterization of propofol binding to plasma proteins and possible interactions].

OBJECTIVES: a) To study the binding of propofol to proteins in plasma samples from healthy volunteers and in solutions of albumin and alpha 1-acid glycoprotein (AGA); b) to describe the nature of the bond and possible interactions with other substances that are potential displacers: salicylate, phenylbutazone, sulfisoxazole, tolbutamide, sodium valproate, sodium oleate and penbutolol; c) to assess the effect of propofol on the binding of specific markers and possible binding sites in the following proteins: 14C-warfarin, 3H-diazepam, 3H-midazolam, 3H-imidazole, 3H-penbutolol and 3H-morphine. MATERIAL AND METHODS: The free fraction was obtained in all samples by ultrafiltration and measurement of the free concentration of propofol by liquid chromatography and of the markers by scintillation spectrometry. RESULTS: The free fraction of propofol in plasma was 0.98 +/- 0.12% and binding was not saturable. Albumin seems to play an important role (95% bound), whereas the participation of AGA was low (54% bound). Propofol did not affect the binding of any of the markers studied. Nor did the presence of other drugs at therapeutic plasma concentrations affect the binding of propofol. CONCLUSIONS: The binding of propofol to plasma proteins seems unlikely to cause drug interactions in clinical practice.

Blood Proteins↗
PubMedDate not supplied

Influence of several surgical techniques in peptic ulcer disease on the oral kinetic of a basic drug.

The effect of gastric surgery on the absorption of a basic drug propranolol was studied in 11 patients. 80 mg of propranolol were administered orally before and after surgery. Irrespective of the surgical technique, there was only a significant decrease in the absorption constant Ka (1.10 +/- 0.14 vs 0.72 +/- 0.09) (p < 0.05), indicating a delay in the gastrointestinal absorption, which agreed with the delay in the urine excretion in the first six hours after surgery (6.8 +/- 0.8 vs 1.7 +/- 0.4) (p < 0.001). Patients with vagotomy but without gastric resection showed a significant increase in the time of attainment of peak concentration tmax (2.4 +/- 0.2 vs 3.2 +/- 0.3), and decrease in Ka (1.5 +/- 0.12 vs 0.73 +/- 0.17) (p < 0.05), indicating also a delay in the gastrointestinal absorption, that is not seen in patients with partial gastric resection. We conclude that vagotomy with gastric resection does not modify the absorption of propranolol, and vagotomy without resection delays its absorption but does not decrease it.

Administration, Oral↗
PubMedDate not supplied

[Allografts in extensive spinal arthrodesis].

Surgery of spinal deformities and vertebral tumors often requires extensive arthrodesis, with the difficulty of obtaining sufficient autogenous bone graft (particularly in children and cases of paralytic deformities) and the necessity of a second incision, thus lengthening the operation and eventual increase of the morbidity. We present 52 patients who suffered from vertebral tumours, fractures or spinal deformities and underwent spinal arthrodesis surgery. Femoral head allografts were used as cancellous bone graft to add to the amount obtained from the arthrodesis bed itself (posterior structures). In three occasions, femoral head grafts shaped as a strut were also used as intersomatic bone graft, being implanted via a costotansversectomy. The only complication was the appearance of seromas of spontaneous resorption in the first 15 cases (thereafter repeated cleaning of the bone graft avoided this problem). In our experience, bone grafts facilitate the carrying out of shorter surgical operations but can also avoid having to recourse the further incisions without reducing the possibility of obtaining a successful arthrodesis.

Adolescent↗
PubMedDate not supplied

[Psychiatric disorders and cognitive deterioration in Friedreich ataxia].

The present study was designed with the aim of examining the presence of psychiatric diagnosis and intellectual impairment in a sample of patients with Friedreich's ataxia. A consecutive sample of 21 patients presenting with Friedreich's Ataxia were evaluated by means of a neuropsychiatric interview. Only one patient was diagnosed as mentally retarded. Out of the 15 patients of the sample who were evaluated with be WAIS, all of them fell within a normal intellectual range. The idea that Friedreich's Ataxia produces cognitive impairment and serious psychiatric symptoms came from the earliest descriptions of the disease at the beginning of this century, which probably included many patients in their samples who had other diseases.

Adolescent↗