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Biomedical subjects

P Picozzi

Publications and source records attributed to P Picozzi.

43 records · Page 3Linked to original sources
PubMedDate not supplied

Simplified, noninvasive PET measurement of blood-brain barrier permeability.

Blood-brain barrier (BBB) permeability to [68Ga]EDTA was measured by positron emission tomography (PET) in four normal volunteers and in 11 patients with brain tumors. A unidirectional transfer constant, Ki, was calculated applying multiple-time graphical analysis (MTGA). This method allows the detection of backflux from brain to blood and, by generalization, the measurement of the constant Kb (brain to blood). Furthermore, the need for an independent measurement of the intravascular tracer is obviated: MTGA itself provides an estimate of the cerebral plasma volume (Vp). In the four normal volunteers the Ki was 3.0 +/- 0.8 X 10(-4) ml g-1 min-1 (mean +/- SD) and the Vp 0.034 +/- 0.007 ml g-1. A net increase in Ki up to a maximum of 121.0 X 10(-4) ml g-1 min-1 (correspondent value of Kb = 0.025 min-1) as well as an increase of Vp was observed in malignant tumors. The input function was calculated using both the [68Ga]EDTA concentration in sequential arterial blood samples and, noninvasively, the activity derived from the superior sagittal sinus image. The values of Ki and Vp from these two calculations were in good agreement. The application of MTGA to PET permits the evaluation of passage of substances across the BBB without making assumptions about the compartments in which the tracer distributes.

Adult↗
PubMedDate not supplied

Reperfusion after cerebral ischemia: influence of duration of ischemia.

The influence of the duration of ischemia on the pattern of cerebral blood flow in recirculation was studied in anesthetised rats. Severe incomplete cerebral ischemia (mean ischemic flow = 5.8 +/- 0.4 ml/100 g/min) was produced by four-vessel occlusion and recirculation permitted after 15, 30 or 60 minutes ischemia. All three groups showed an immediate hyperemia followed by hypoperfusion. Hyperemia was maximal following 15 minutes ischemia and least pronounced following 60 minutes ischemia (p = 0.0249). Hypoperfusion started most quickly following 15 minutes ischemia and was delayed following 60 minutes ischemia (p less than 0.001). In established hypoperfusion there was no difference in flow between the three groups. The possible mechanisms of these changes in flow are discussed.

Animals↗
PubMedDate not supplied

Duration of ischemia influences the development and resolution of ischemic brain edema.

The influence of the duration of ischemia on the development and resolution of post-ischemic brain edema (SG method) was studied in anesthetized rats. Edema developed during ischemia and the amount of edema was related to the duration of ischemia (r = 0.843, p less than 0.001). With recirculation to three hours, the major determinant of the amount of edema was still the duration of the preceding ischemia (p less than 0.001). Resolution of brain edema only occurred following fifteen minutes ischemia. Post-ischemic blood-brain barrier breakdown (14C-AIB, EB albumin) was greatest following longer ischemia. Where present, the BBB leakage was simultaneously to large and small molecules.

Animals↗
PubMedDate not supplied

[An assessment of neuronal regeneration in neural anastomoses by synthetic guide and biological systems and insulin administration: an experimental study in the rat].

The synthetic and biological nerve guide regeneration gives interesting perspective of use in making artificial conduits for peripheral nerve reconstruction. In sixty Wistar rats, under general anesthesia and with microsurgical technique, the ischiatic nerve was isolated. On the right side a segment of the nerve was removed in order to create a 10 mm gap. The defect then repaired using the conduit. Control were performed at 20, 90, 180 days and consisted in histological microscopy and electromyography investigation. The regeneration of the nerve fibers in the lumen of the conduit was not significantly different on the contralateral nerve limb.

Administration, Topical↗
PubMedDate not supplied

[Diagnostic problems and results of laparoscopic cholecystectomy in chronic acalculous cholecystitis].

We report on our experience with laparoscopic cholecystectomy in 15 patients, 12 females and 3 males (mean age: 44 years), with chronic acalculous cholecystitis. These patients presented with recurrent episodes of biliary colic together with a dysmorphic or dysfunctioning gallbladder as confirmed by ultrasound and/or cholescintiscan with 99m-Tc HIDA performed in fasting conditions and after meals. First of all, we considered the possible presence of concomitant digestive disease (peptic ulcer disease, recurrent pancreatitis, irritable bowel syndrome, chronic hepatitis) potentially responsible for the pain. Ultrasound investigations revealed a pathological gallbladder in 10 patients. Cholecystectomy was curative in 8/10. Cholescintiscan revealed a pathological gallbladder in 8 patients and cholecystectomy was curative in only 5 of these. No postoperative deaths or significant complications occurred. The mean duration of the operation (35 vs 48 min) and hospital stay (2.1 vs 2.8 days) were reduced in comparison to 346 cholecystectomies performed for gallstones. After 6-36 months' follow-up, resolution of symptoms was successful in 10/15 cases (66.6%); in 3 cases, only dyspepsia was reduced, whilst in the other 2 cases, who also presented concomitant irritable bowel syndrome and gastroduodenitis, there was no improvement in pain. In all but the latter two cases (86.6%), histological examination revealed chronic gallbladder inflammation. In conclusion, laparoscopic cholecystectomy was curative (66.6%) or led to an improvement in symptoms (20%) in patients with chronic acalculous cholcystitis. Cholescintiscans were not always diagnostic for the disease, whereas ultrasound findings were more useful as an indication for surgery.

Adult↗
PubMedDate not supplied

[Multicenter prospective study of informed consent in general surgery].

To understand the level of acceptance, awareness and usefulness of informed consent, a group of 119 patients (59 men and 60 women) from different types of hospitals were given a questionnaire which required only 'YES or NO' answers, both before and after surgery. The questionnaire concerned the patient's knowledge about pathology, operative risks, approval, anxiety caused, understanding of information received and consent given, and also if he would inform a relative in the same condition. From the analysis of the results it was established that: the more information a patient has about his illness and operation risks, the more he will want to have; the less he knows the less he will want to know, and he will also have more faith in the doctors. Some patients would not inform a relative with a similar pathology. To conclude, informed consent, instead of being a right of the patient is progressively becoming more a right of the doctor. It does not have any real effect on the patient's choice but is useful, as it represents a moment of personalised attention from medical personnel, though the patient may not completely understand the information received. There are few advantages in strictly medical terms but informed consent has increased malpractice litigation.

Female↗