Search PubMed⌕ Search

Biomedical subjects

G La Greca

Publications and source records attributed to G La Greca.

At least 109 records · Page 6Linked to original sources
PubMed1990

Pathophysiology of ultrafiltration in peritoneal dialysis.

Pathophysiology of peritoneal ultrafiltration is analyzed in the present study. Peritoneal equilibration test is the easiest procedure to study in detail the possible causes of failure to control the ultrafiltration rate in patients undergoing peritoneal dialysis. Membrane failure, reduction in peritoneal blood flow, excessive lymphatic reabsorption catheter malposition, and fluid sequestration are the most common causes of ultrafiltration loss. Pharmacologic manipulation of peritoneal membrane, correction of mechanical inconvenients, reduction in peritonitis rate and in the level of immunostimulation of the mesothelial macrophages, together with a careful policy in terms of glucose concentration in the dialysate and dwell times may contribute not only to treat different forms of ultrafiltration loss but also to prevent their incidence.

Algorithms↗
PubMed1989

Pancreas transplantation in the rat using Lee's technique: a reliable model in experimental microsurgery.

Numerous unresolved problems, both technical and immunological, in pancreas transplantation stimulate experimental studies. Dogs have been routinely used in experimental studies but today rats are more commonly used. However, pancreas transplantation in the rat presents complex technical problems and requires a good knowledge of microsurgical techniques. In 1983 Squifflet undertook an experimental study aimed at evaluating the technical aspects of pancreas transplantation in the rat and calculating the success rates using different methods. The comparison of four methods revealed to our surprise that 100% of the rats operated on using Lee's technique had complications, with a 0% survival rate. In our study we report our experience using Lee's technique which we had the opportunity of mastering directly under the supervision of Professor Lee. We performed 100 pancreas transplantations using Lee's technique and divided our study in two phases. In the first phase we performed 70 pancreas transplantations and overall survival, after 1 week, was 42 rats (60%). In the second phase on 30 rats diabetes was induced by administering 70 mg/kg of streptozotocin. These 30 diabetic rats underwent pancreas transplantation and overall survival, after 1 week, was 25 (83.3%). We believe that our successful survival rates could probably be explained by the close collaboration between Lee and our department. Moreover, we noted the importance of constant training in obtaining better results, and in our opinion Lee's technique of pancreas transplantation is a reliable experimental model which can be used to resolve problems linked to pancreas transplantation.

Animals↗
PubMed1989

[Carcinoma of the male breast].

The Authors, after a brief review of the most important epidemiologic, etiologic, diagnostic and therapeutic problems related to male breast cancer, report their personal experience. They point out the importance of an early diagnosis in order to obtain satisfactory results, comparable to those achieved in female breast cancer treatment.

Aged↗
PubMed1989

Carcinoma of the male breast and ocular metastases.

Breast carcinoma in males associated with ocular metastases is not often observed. A case is reported with review of the literature. Medical management is satisfactory in case of metastases and enucleation is suggested for severe pain.

Adenocarcinoma, Scirrhous↗
PubMed1989

[Role of gonadal phlebography in the diagnosis of cryptorchidism].

The authors describe the diagnostic procedures for testicular localization in patients with non palpable undescended testes. They consider the procedures as invasive and non invasive. The first procedures include ultrasonography, C.T. and N.M.R., the second ones laparoscopy, selective arteriography and venography of the spermatic vessels. Anatomy of spermatic venous system and catheterization techniques are described. Conclusions are that when non invasive procedures fail to localize the testis, gonadal venography is the procedure of choice for the correct diagnosis. Preoperative testicular localization often reduces the extent of surgical exploration and the anesthesia time. These patients have to undergo surgical treatment also when gonadal venography shows a blinding end vein in the inguinal canal, because of the intra-abdominal testis possible degeneration.

Adolescent↗
PubMed1989

Acid base correction in bicarbonate CAPD patients.

Bicarbonate has been proposed as buffer in CAPD solutions in recent years instead of lactate and acetate. The present study is designed to evaluate peritoneal bicarbonate kinetics using bicarbonate solutions. Seventy kinetic studies have been performed in 7 patients treated with 2 CAPD solutions containing 35 mmol/l (A) and 27 mmol/l (B) of bicarbonate. The changes in dialysate bicarbonate concentration at different dwell times were correlated with bicarbonate blood levels. Furthermore after 2 hours of dwell time and at subsequent observations, no differences in dialysate bicarbonate concentration were found between A and B solutions at the same bicarbonatemia. Thus a feedback between bicarbonate absorption and bicarbonate blood concentration was observed. If the amount of bicarbonate transferred to the patient is over the metabolic acid production, bicarbonatemia will rise: consequently bicarbonate dialysate absorption will decrease. After a few days, an equilibrium point will be reached. In this condition the bicarbonate absorption is equal to metabolic acid production and, in stable clinical conditions, a stable acid base status will be maintained by the patient. Our studies empirically demonstrated that the equilibrium is reached when a difference of 5 mmols between blood and inlet dialysate bicarbonate concentration is observed. Consequently to achieve 25 mmol/l of bicarbonatemia, the bicarbonate concentration of CAPD solution should be about 30 mmol/l.

Acetates↗
PubMed1989

Technical and clinical evaluation of a new synthetic low flux polysulphon membrane for hemodialysis.

New synthetic membranes have been developed to reduce the ultrafiltration coefficient (Kf) maintaining an adequate permeability to medium-large solutes and a good biocompatibility. The new Fresenius F6 Low Flux Polysulphon Membrane is studied in this paper as far as hydraulic and permeability properties are concerned. For this purpose in vitro and in vivo tests have been carried out in a series of different conditions. In vitro sieving coefficients were near 1 for solutes with molecular weight up to 5000 Daltons. The ultrafiltration coefficient of the device was 5.4 ml/h/mmHg while the value of Kf normalized per square meter was lower than 5 ml/h/mmHg. The geometry of the blood path was adequate even operating at high blood flows without excessive resistance and obligate filtration. This resulted in vivo in a good performance during short dialysis schedules with good clearances of small and large molecules and with no risks of backfiltration. In fact, the low permeability to water permits constant operation with positive transmembrane pressures without excessive ultrafiltration rates. The biocompatibility of the membrane was excellent and high capacity of adsorption for beta-2 microglobulin was demonstrated. These results suggest that these membranes seem to be able to join the advantages of the traditional cellulosic membranes and of the newer synthetic membranes reducing their relative disadvantages.

Biocompatible Materials↗
PubMed1989

New method of extracorporeal concentration of ascitic fluid as a treatment of refractory ascites.

A new piece of equipment for the treatment of ascites is described. Ascitic fluid is drained by gravity in a unit consisting of an Amicon D-30 ultrafilter and a bag used as transit reservoir placed below the patient. When the bag is full, it is raised to a height sufficient to let the fluid flow back through the filter to the peritoneal cavity. Mainly during this step ultrafiltration of ascitic fluid occurs through the membrane of the filter. Ultrafiltration is enhanced by the negative pressure created in the filtrate compartment due to the height difference between filter unit and filtrate drainage bag placed at the bottom of the machine. Proteins in the ascitic fluid are retained and returned to the abdominal cavity. The machine cycle is automatically repeated as many times as necessary to achieve the scheduled patient weight loss. 17 patients have been treated for a total of 1.94 sessions/patient with reinfusion of the fluid in the abdominal cavity. In all patients a significant reduction of the amount of ascitic fluid and of its rate of formation have been achieved. The treatment was well tolerated and no side effects were observed. After treatment the diuresis and the sodium excretion increased significantly in all patients. The system is safe and reliable for the treatment of refractory ascites without major complications.

Adult↗
PubMed1988

Radio-hyperthermia for subcutaneous metastasis of hemangiopericytoma of the mediastinum: case report.

Hemangiopericytoma is a rare type of neoplasia originating from the Zimmermann pericytes and can arise in numerous sites. As it is difficult to correlate the histologic aspect with the prognosis, it was considered advisable to take account of other factors such as age and tumoral site. Aggressive surgery followed by irradiation therapy is suggested as the most suitable management. Hyperthermia also was adopted in treating subcutaneous metastasis, but its role has yet to be fully defined.

Age Factors↗
PubMed1988

High-flux haemodialysis with 1.5 m2 modified cuprammonium rayon membrane: technical and clinical evaluation.

The feasibility and reliability of a short dialysis technique performed with standard dialysis equipment and a modified cuprammonium rayon hollow-fibre filter has been studied. The hydraulic response of the filter and membrane to high blood flows and transmembrane pressures were tested in vitro and the maximal clearances of different solutes achievable during high-flux bicarbonate dialysis were studied in vivo. Clinical studies were undertaken to evaluate the long-term effects of the short, highly efficient dialysis therapy. Six patients were treated for more than a year with single-pass bicarbonate dialysis with a blood flow of 500 ml/min, dialysate flow of 700 ml/min, and average duration of 150 min/session three times weekly. The treatment showed an adequate efficiency with an average KT/V greater than 1. All patients obtained an average blood urea nitrogen during the study of less than 80 mg/dl and an average protein catabolic rate of 0.9 g/kg per 24 h. The treatment was well tolerated by all patients and, on echocardiography, no significant changes in myocardial function were detected after one year of therapy. The treatment is efficient, well tolerated, simple to monitor and does not require the use of synthetic membranes or machines with advanced technology. Thus the reduction of dialysis treatment time is feasible in all centres at a relatively low cost.

Adult↗
PubMed1988

Male hypogonadism of uremic patients on hemodialysis.

Primary hypogonadism occurring among uremic men on hemodialysis has been widely investigated, yet few data are available concerning the general pattern of steroidogenesis. In 161 hemodialysis patients and in 83 healthy subjects, serum levels of gonadotropins (LH and FSH), prolactin (PRL), testosterone (T), androstenedione (A), estrone (E1), estradiol (E2), and dehydroepiandrosterone-sulphate (DHEA-S) were assessed through RIA methods. Mean +/- SD hormone levels were: LH 45.6 +/- 41.1 mIU/ml, FSH 16.3 +/- 16 mIU/ml, PRL 42.4 +/- 69.1 ng/ml, A 0.83 +/- 0.27 ng/ml, E1 64.3 +/- 31.7 pg/ml, all higher than controls; T 289 +/- 125 ng/100 ml, E2 11.8 +/- 3 pg/ml, and DHEA-S 1.4 +/- 1.4 micrograms/ml, all lower than controls. The A/T and E1/E2 ratios were also higher than controls and showed a good positive linear correlation (r = 0.40; p less than 0.001) between each other. The uremic damage acts at the testis level, impairing the activity of the enzyme 17-beta-hydroxysteroid-dehydrogenase (17-OHSD), even if a derangement of the peripheral interconversion between steroids cannot be excluded.

Adult↗