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Biomedical subjects

P Marchini

Publications and source records attributed to P Marchini.

13 recordsLinked to original sources
PubMed1998

[Role of hypertension in determining valvular diseases in patients with chronic uremia and dialytic treatment].

Patients in chronic dialysis have a higher prevalence of cardiovascular morbidity and mortality, together with higher prevalence of hypertension and valvular diseases. It is not clear whether aortic and mitral defects are linked to the effect of chronic dialysis (for instance hypercalcaemia or hyperparathyroidism) or to hypertension. In order to see whether these factors could independently affect the single valve diseases we studied 48 patients in chronic dialysis. Patients were divided into hypertensive and normotensive. A population of hypertensive and another of normotensive, non-dialyzed patients served as control. The presence of valvular disease was searched by mean of echocardiography. We also investigated the length of dialytic treatment and the levels of parathyroid hormone in order to see if any correlation with the single valve defects existed. Aortic stenosis and insufficiency were not related to hypertension suggesting that circulating factors are likely to be involved in the pathogenesis of this valvulopathy (chi 2 = 6, p < 0.01 between hypertensive and normotensive in dialysis; chi 2 = 6.1, p < 0.01 between patients in dialysis and normotensive non uremic, for aortic stenosis; chi 2 = 12.1, p = 0.02 between non uremic normotensive and dialyzed, for aortic insufficiency). On the contrary for mitral regurgitation we did not find differences between dialyzed patients and controls (chi 2 = 18.2, p < 0.0001 between uremic hypertensive and controls). There was a significant difference in both groups between hypertensive and normotensive subjects suggesting that hypertension plays an important role in this valvulopathy. Mitral and aortic calcifications were more frequent in the uremic patients (55% in hypertensive uremics, 33% in normotensive uremics, 16 and 25% in non uremics).

Aged↗
PubMed1995

A new approach to blood pressure and blood volume modulation during hemodialysis: an adaptive fuzzy control module.

The paper proposes a fuzzy logic based procedure able to control as far as possible the behaviour of the blood pressure of a patient during a dialysis session, allowing him to reach the foreseen dry weight. A PI discrete-time fuzzy control is used in order to compare the controlled variables concerning the (blood pressure and blood volume) to the reference values. Two different reference tables, concerning the pressure and volume errors and rates are introduced, then the proposed control actions are mixed in order to obtain the final value (net ultrafiltration rate). A smooth function of volemia acts on the second control variable, Na concentration in the dialysate. The adaptive control system was simulated on an IBM-PC, rules and terms were expressed by linguistic judgements like: IF "situation", THEN "action". A pre-processor converts the rules into the numerical values of the reference tables. The obtained simulation results are satisfactory, the introduction of the Na control allows reaching the target dry weight of the patient with a stable blood pressure.

Adult↗
PubMed1985

[Synthesis and antiinflammatory activity of various 1,4-benzothiazine derivatives].

A new series of dihydro-4H-1,4-benzothiazine derivatives was prepared. These compounds were obtained by reductive N-alkylation reaction with sodium borohydride in acetic acid of the corresponding 4H-1,4-benzothiazine. Some of the latter compounds were synthesized by a new synthetic method employing 2-aminobenzenethiol and alkynes as starting material. Preliminary pharmacological data on the antiinflammatory activity of these compounds by using carrageenin paw edema assay are reported.

Animals↗
PubMed1984

Effect of hyperprolactinemia and age on the hypogonadism of uremic men on hemodialysis.

Primary hypogonadism has been commonly reported among uremic men on hemodialysis, characterized by low testosterone levels, increased luteinizing hormone and sometimes follicle-stimulating hormone levels. Little is known about the influence of hyperprolactinemia and age on this hypogonadism. In 149 hemodialysis patients and in 60 healthy subjects the serum levels of testosterone (T), gonadotropins (LH and FSH) and prolactin (PRL) were assessed through radioimmunoassay. Mean +/- SD hormone levels were: T 274 +/- 125 ng/100 ml, lower than controls; LH 44.7 +/- 46.1 mlU/ml and FSH 17.6 +/- 18.4 mIU/ml, both higher than controls. PRL 31.3 +/- 49.4 ng/ml, higher than controls. A positive correlation between LH and FSH, a negative correlation between PRL and both T and LH was found. Moreover T and FSH were correlated with age only in the normoprolactinemic patients. These data suggest: a common damaging mechanism by uremia on both interstitial and tubular structures of the testis; a central antigonadal influence of hyperprolactinemia even if a direct action on the testis cannot be excluded; a worsening action of age on the gonadal function of these patients.

Adult↗
PubMed1980

[Hydrogenated and cyclohomologous derivatives of phenothiazine. Synthesis and pharmacological activity of various cycloalkyl derivatives of 4H-benzo(b)(1,4)thiazine].

The synthesis and the results of pharmacological screening of 4H-benzo[b][1,4]thiazine derivatives are described. These substances were prepared by reacting 2,2'-dithiodianiline with ethyl-2-oxocycloalkanecarboxylates followed by NaBH4 reduction. The pharmacological results indicate remarkable depressive activity [see (IV b) (n = 3)] shown by 100% potentiation of barbituric-induced sleeping time.

Animals↗
PubMedDate not supplied

Projection and simulation results of an adaptive fuzzy control module for blood pressure and blood volume during hemodialysis.

This paper proposes a fuzzy logic based procedure able to control the behavior of a patient's blood pressure during a dialysis session, allowing him to reach the planned dry weight. A proportional integrative discrete-time fuzzy control is used to subject the controlled variables (blood pressure and blood volume) to the reference values. Two different tables that refer to pressure and volume errors and rates are consulted and the proposed control actions are taken to obtain the final value (net ultrafiltration rate). A saturation-threshold function of volemia acts on the second control variable, Na concentration in the dialysate. The adaptive control system was simulated on an IBM PC, and rules and terms were expressed by linguistic judgments such as: IF "situation," THEN "action." A pre processor converts the rules into the numerical values in the tables. The obtained simulation results are satisfactory, and the introduction of Na control allows achievement of the target dry weight of the patient with a stable blood pressure.

Adaptation, Physiological↗
PubMedDate not supplied

[Census 2004 of the Italian Renal and Dialysis Units. Veneto, Friuli Venezia Giulia and Trentino Alto Adige].

The Italian Society of Nephrology (SIN) promoted a national survey of the Renal and Dialysis Units using an online questionnaire on some aspects of structural, technological and personnel resources, as well as organisation and activity. The major aim of this initiative was to obtain a reference benchmark on a national and regional basis. In this paper the data of the northestern regions of Italy (Veneto, Friuli-Venezia Giulia and Trentino-Alto Adige) are reported and compared with the recently published results of the northwestern regions (Piedmont, Liguria and Valle d'Aosta). From an epidemiologic point of view, the prevalence of dialysis patients was 534 pmp (per million population) in Veneto, 667 pmp in Friuli VG and 545 in Trentino AA, the prevalence of transplanted patients was 265, 294 and 404 pmp, respectively; the incidence of dialysis patients was 137, 182 and 130 pmp; gross mortality was 12.5, 14.3 and 16.5%; the distribution of vascular accesse in prevalently dialysis patients was: arteriovenous fistulas = 84.5, 70.4 and 80.9%, central venous catheters = 10.6, 20.0 and 10.2%, vascular graft = 4.9, 9.6 and 8.8%. Regarding structural resources, the distribution of hospital bed numbers was 38, 42 and 43 pmp; dialysis places were 137, 181 and 172 pmp. Human resources were given by renal physicians = 28.3, 38.2 and 23.6 pmp and renal nurses = 138, 200 and 172 pmp; each renal physician took care of 19, 17 and 23 dialysis patients and each renal nurse cared for 3.9, 3.3 and 3.2 dialysis patients. Activity data showed 1436, 1328 and 974 pmp hospital admissions, kidney biopsies were 106, 114 and 31 pmp. Overall, the Italian Northeast shows a significantly lower prevalence and incidence of end-stage renal disease patients than the Northwest; on the contrary, the incidence of patients with acute renal failure is significantly higher. In the Italian Northeast a significantly lower number of hospital beds devoted to renal patients is observed, while dialysis places are more frequent. In the Northeast fewer renal physicians are present than in the Northwest, whereas renal nurses are equivalent if related to the number of dialysis patients. Activity indexes, intended as amount of hospital admissions and renal biopsies standardised per population, are less significant in the Northeast. The results of the survey in Veneto, Friuli VG and Trentino AA show some discrepancies in the treatment of chronic kidney disease between the three regions and even more among different areas of Italy. Despite similar health care models, a relevant inequality in health care resources is evident.

Ambulatory Care Facilities↗