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Biomedical subjects

R Caprioli

Publications and source records attributed to R Caprioli.

At least 19 recordsLinked to original sources
PubMed2001

Clinical relevance of cardiac natriuretic peptides measured by means of competitive and non-competitive immunoassay methods in patients with renal failure on chronic hemodialysis.

Increased levels of cardiac natriuretic peptides in patients undergoing hemodialysis may be a marker of cardiomyopathy and in consequence may be suitable prognostic indicators for the risk of development of cardiac disease. We measured plasma levels of ANP, BNP, proANP(1-98) and proBNP(1-76)-related peptides with some competitive and non-competitive immunoassay methods in patients with renal failure on chronic hemodialysis in order to compare the analytical performances of these methods and to evaluate the clinical usefulness of each assay for patients with chronic renal failure. ANP and BNP values significantly decreased after hemodialysis (on average, ANP by 36% and BNP by 16%); while all proANP and proBNP values tended to increase, but only proANP(1-30) (by 14.4%) and Nt-proBNP (by 9.5%) significantly. Although significant correlations were found among all the circulating levels of cardiac peptides studied, N-terminal pro-peptides correlated better among themselves than with ANP and BNP; ANP was only slightly correlated with all the other peptides, the only exception being BNP. Only BNP levels significantly increased according to the degree of ventricular hypertrophy and/or ventricular function in patients with chronic renal failure. The ANP assay is preferable in physiological and clinical studies for the rapid changes in atrial pre-load. BNP would be more useful in the follow-up of cardiac complications in patients with end-stage renal disease on regular hemodialysis. The assays of N-terminal proANP(1-98)-and proBNP(1-76)-related peptides proved to be of limited use, because they were not able to detect acute changes in pre-load during hemodialysis and were less useful than BNP levels as markers of ventricular hypertrophy and/or functional cardiac impairment.

Adult↗
PubMed2001

Changes in heart rate variability in chronic uremic patients during ultrafiltration and hemodialysis.

BACKGROUND: The analysis of heart rate variability (HRV) is a useful tool to evaluate cardiac autonomic modulation, which is frequently impaired in chronic uremia. AIMS: The aim of this study was to evaluate HRV in chronic uremics and to separately investigate the acute changes induced by volume depletion and solute removal during a hemodialysis session. METHODS: Fourteen uremic patients (8 males and 6 females, aged 50 +/- 15 years) on maintenance hemodialysis and 14 sex- and age-matched healthy controls were studied. Both groups underwent ambulatory electrocardiogram monitoring to evaluate the HRV time and frequency domain indices. The hemodialysis session was performed by 1 h of high-rate isolated ultrafiltration followed by 3 h of bicarbonate diffusive procedure. RESULTS: In uremic patients, the overall variability in the frequency [low-frequency power (LF): 505 +/- 473, vs. 1,446 +/- 654; high-frequency power (HF): 133 +/- 162 vs. 512 +/- 417; p < 0.001] and time domain indices (standard deviation of normal R-R intervals: 101.9 +/- 33.3 vs. 181.7 +/- 44.1 ms; p < 0.001) was markedly reduced compared to controls, whereas mean heart rate (83 +/- 12.4 vs. 60.9 +/- 8.8 bpm; p < 0.001) and LF/HF ratio (5.8 +/- 3.5 vs. 2.2 +/- 0.8; p < 0.001) were increased. Isolated ultrafiltration produced a marked further decrease in HRV indices, but the subsequent diffusive hemodialysis procedure, with a low ultrafiltration rate, made HRV increase again. CONCLUSIONS: Chronic uremics showed abnormal autonomic modulation with sympathetic-vagal imbalance. The unbalanced hypersympathetic response to body fluid depletion is related to the ultrafiltration rate. Low interdialytic weight gain and a low ultrafiltration rate, associated with adequate hemodialysis, should be the preferable strategy for uremic patients with autonomic dysfunction.

Adult↗
PubMed2000

Responses of the skin microcirculation to acetylcholine and to sodium nitroprusside in chronic uremic patients.

The aim of the present study was to assess the endothelial function of the microcirculation in chronic renal failure. We investigated the responses of the cutaneous blood flow to locally delivered acetylcholine and sodium nitroprusside in uremic patients. The study included 60 chronic uremic patients: 40 patients with a creatinine clearance of 4-25 ml/min were on conservative treatment and 20 patients were on maintenance hemodialysis. The changes in skin blood flow following iontophoretic delivery of acetylcholine (an endothelium-dependent vasodilator) and sodium nitroprusside (an endothelium-independent vasodilator) were measured by laser Doppler flowmetry. Acetylcholine induced a progressive increase in blood flow in both groups, reaching approximately 100% of the maximal hyperemic response obtained by sodium nitroprusside delivery. The percent increase in blood flow from baseline was lower in hemodialysis patients than in patients on conservative treatment, after both acetylcholine (550 +/- 44 vs. 718 +/- 61%, P < 0.05) and sodium nitroprusside (553 +/- 46 vs. 735 +/- 69%, P < 0.05) delivery. In the hemodialysis group, the hyperemic responses to acetylcholine and sodium nitroprusside did not improve after the hemodialysis session. Hence, the hyperemic responses of the skin microcirculation are lower in hemodialysis patients than in patients on conservative treatment, and did not ameliorate after hemodialysis. It seems to be independent of endothelial dysfunction, and associated with the severity of uremia and with the maintenance hemodialysis treatment. This microcirculatory abnormality is in keeping with the arterial stiffness and vascular wall damages described in dialysis patients, which contribute to the cardiovascular morbidity of chronic uremia.

Acetylcholine↗
PubMed2000

Measurement of brain natriuretic peptide in plasma samples and cardiac tissue extracts by means of an immunoradiometric assay method.

We evaluated the analytical characteristics and clinical usefulness of a commercial immunoradiometric assay (IRMA) kit for brain natriuretic peptide (BNP). Mean (+/-SD) plasma BNP concentrations measured in 129 normal subjects were 2.9+/-2.7 pmol/l (median 2.2 pmol/l; range 0.1-12.4 pmol/l). The mean (+/- SD) value observed in healthy men (2.1 +/- 2.0 pmol/l, n = 49) was significantly (p=0.0009) different to that found in women (3.4 +/- 2.9 pmol/l, n=80). A positive relationship (R=0.214, p=0.0174) was found between BNP values and age. In 65 patients with cardiac diseases, BNP levels increased with the progression of clinical severity of disease; patients with more severe disease [NYHA functional class III-IV, mean (+/- SD) BNP +/- 254 +/- 408 pmol/l, n=22] showed significantly (p<0.0001) increased values compared to patients with mild symptoms of disease (NYHA functional class I-II, mean (+/- SD) BNP=19.6 +/- 17.2 pmol/l, n=43). Furthermore, in 32 patients with chronic renal failure, greatly increased (p<0.0001) BNP values were found both before (mean +/- SD=88. 1+/- 111.1 pmol/l) and after haemodialysis (mean +/- SD=65.6 +/- 76.7 pmol/l), with a significant reduction after haemodialysis (p=0.0004) compared to pre-haemodialysis. The mean (+/- SD) BNP value found in atrial extracts collected during aorto-coronary bypass operations in 15 patients was 14.5 +/- 51.9 pmol/g of cardiac tissue. Moreover, the mean (+/- SD) tissue levels of BNP in 7 heart transplant recipients were 128.4 +/- 117.2 pmol/g of cardiac tissue in atrium, 68.4 +/- 76.7 pmol/g in ventricle, and 10.9 +/- 8.5 pmol/g in interventricular septum. Finally, BNP values found in cardiac tissues of two subjects collected at autopsy were considerably lower (on average 1/1000) than those observed in cardiac tissues of patients with cardiac diseases. The IRMA method for BNP determination evaluated in this study showed a good degree of sensitivity, precision and practicability. Therefore, this method should be a reliable tool for the measurement of plasma BNP levels for both experimental studies and routine assay.

Adult↗
PubMed1999

Potassium removal increases the QTc interval dispersion during hemodialysis.

This study was planned to clarify the mechanism(s) by which hemodialysis increases the QTc dispersion, a marker of risk of ventricular arrhythmias. To this aim, 10 uremic patients, without any relevant heart diseases, underwent two different types of hemodialysis schedules. In the first, 1 h of isolated high rate ultrafiltration preceded the standard diffusive procedure. In the second, during the first hour of standard bicarbonate hemodialysis, the decrease of plasma potassium concentration was prevented by increasing K+ concentration in the dialysate, according to its pre dialysis plasma levels. During the high rate ultrafiltration period, together with ECG signs of increased sympathetic nervous system activity and catecholamines secretion, the QTc dispersion did not change significantly. Instead, an evident increment was observed 1 h after the start of the diffusive hemodialysis, then slowly progressing until the end of the dialysis and finally returning to the pre dialysis values within 2 h after the end of the session. To the contrary, the increase of the QTc dispersion was totally blunted during a standard hemodialysis procedure in absence of plasma K+ decrease, but appeared again when the K+ dialysate fluid concentration was restored to 2 mmol/l. This study provides evidence that the increase of QTc dispersion occurring on hemodialysis is mainly related to the diffusive process, more precisely to the K+ removal. This is one more reason to focus attention on K+ removal rate especially when hemodialysis treatment is given in uremics affected by cardiac diseases with high risk of arrhythmias.

Blood Pressure↗
PubMed1996

Omega-3 fatty acid supplementation and lipoprotein(a) concentrations in patients with chronic glomerular diseases.

Renal disease patients often exhibit alterations in the lipid profile which may become an important risk of accelerated atherosclerosis and contribute to disease progression. Among such alterations, increased levels of lipoprotein(a) [Lp(a)] are common and may be related, in part, to the degree of proteinuria. Omega-3 polyunsaturated fatty acids (omega-3 FA) have been reported to decrease Lp(a) concentrations in nonrenal subjects. In addition, they have recently been shown to reduce proteinuria in patients with chronic glomerular disease. We therefore tested the hypothesis that omega-3 FA treatment in patients with chronic glomerular disease may reduce Lp(a) concentrations. Eight patients (2 with membranous glomerulonephritis, 6 with focal glomerular sclerosis) were submitted to a total of 13 six-week courses of treatment with omega-3 FA, at a dose of 3 g/day with a triglyceride preparation (n = 4) and of 7.7 g/day with an ethyl-ester preparation (n = 9). Both treatments significantly increased the proportions of omega-3 to omega-6 FA in total serum lipids, documenting compliance to treatment. Both treatments were also effective in decreasing serum thromboxane (from mean 490 +/- (SEM) 70 to 325 +/- 49 ng/ml, p < 0.05, in the high-dose group) and prolonging the bleeding time (from 5.8 +/- 0.4 to 7.7 +/- 0.5 min, p < 0.05, in the high-dose group), thus documenting the biological efficacy of treatment. However, despite a significant reduction in serum triglyceride levels (from 137 +/- 20 to 104 +/- 19 mg/dl in the high-dose group), Lp(a) concentrations did not change (292 +/- 120 U/l before, 315 +/- 130 U/l after the high-dose therapy). Treatment-related changes in proteinuria (from 2.9 +/- 0.5 to 2.1 +/- 0.7 g/24 h) were not related at all to changes in Lp(a) levels. We conclude that omega-3 FA do not decrease Lp(a) concentrations in renal patients with chronic glomerular diseases and that Lp(a) levels are unlikely to be related to the degree of proteinuria within the short-term modifications induced by omega-3 FA.

Adult↗
PubMed1995

Recombinant human erythropoietin and high flux haemodiafiltration.

Since 1982, 32 uraemic patients were treated in our institution by high flux haemodiafiltration (H-HDF) in order to shorten significantly the dialytic treatment session. H-HDF used a high surface area filter (1.4-1.9 m2) with high hydraulic permeability (polyacrylonitrile and polysulfone), at high blood flow (450 ml/min) and high rates of reinfusion of substitution fluid (22 l/session). In this way the dialytic session was shortened to 140 +/- 19 min, maintaining a good cardiovascular stability and high dialytic efficiency (Kt/V > 1.1). Human recombinant erythropoietin rHuEpo introduced in the therapy of this group in 1987 has resulted in an improvement of renal anaemia, but also a prolongation of the time of dialytic treatment due to a decrease in the efficiency of filters. During the period of the study, the treatment time increased from 140 +/- 19 min to 168 +/- 25 min with a concomitant increase of haematocrit and haemoglobin (from 24% to 36% and from 7.9 to 10.5 g/dl, respectively). H-HDF maintains a noticeable increase in dialytic efficacy with good cardiovascular stability, but the goal of a significant reduction in the time of treatment can no longer be obtained.

Adult↗
PubMed1993

n-3 fatty acids reduce proteinuria in patients with chronic glomerular disease.

Dietary supplementation with n-3 polyunsaturated fatty acids (n-3 PUFA) has been shown to reduce proteinuria in experimental models of renal diseases, but their potential role in the treatment of human renal disease is unknown. We administered n-3 PUFA in the form of triglycerides [with eicosapentaenoic (EPA)+docosahexaenoic (DHA) = 3 g/day into 4 patients] and of ethyl esters (EPA+DHA = 7.7 g/day) into 10 patients (one patient twice) with chronic glomerular disease (membranous glomerulonephritis and focal glomerular sclerosis), all diagnosed histologically. Serum albumin was > 2.4 g/dl and serum creatinine < 2.5 mg/dl in all patients. Treatment was given for periods of six weeks, followed by a prolonged follow-up for 27 weeks in 10 cases. Dietary supplementation with n-3 PUFA caused the expected reduction in platelet generation of thromboxane B2 (mean +/- SEM, from 490 +/- 70 ng/ml at baseline, to 342 +/- 147 ng/ml at 6 weeks, P < 0.05) of serum triglycerides (from 236 +/- 60 to 170 +/- 43, P < 0.01), and a prolongation of the bleeding time (from 5.8 +/- 0.4 min to 7.7 +/- 0.4 min, P < 0.01) in patients treated with ethyl esters. A modest but significant reduction in serum total cholesterol was noticed (from 275 +/- 27 to 252 +/- 24 mg/dl).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

Surgical nail procedures.

As the so-called "non-surgical" nail procedures grow more and more aggressive and invasive in nature, the cold steel matrixectomy becomes an increasingly viable alternative. Many chemical and thermal matrixectomies are performed under poor aseptic conditions, increasing the risk of wound infection. With chemical matrixectomy, regulation of the level of tissue destruction is uncontrolled and often results in bone injury. The combination of these two elements can result in delayed diagnosis and recognition of osteomyelitis. When a practitioner is faced with a challenging ingrown, dystrophic, or mycotic nail, surgical nail removal should be considered the preferred technique. Etiologic variants of nail deformity, such as hypertrophied ungual labia, subungual exostosis, traumatized nail, and prominent underlying bony condyles, are well managed by the two procedure modifications presented. Advantages in asepsis, quicker wound healing, low reoccurrence rates, and good postoperative cosmesis make surgical nail removal a good choice. The difficulty of the technique and the danger of bone infection have frightened many practitioners away from the cold steel nail procedure. The preferred phenol technique or "p and a" may be simpler to perform, but it yields an unpredictable result. The constant draining and erythema of a phenolized nail may mask an underlying infection. This is one reason why cold steel nails are the preferred technique for nail removal in a diabetic patient. Complications makes cold steel a necessary addition to the surgeons armamentarium. We have presented a brief clarification and historical overview of the four most important contributors to surgical nail removal. These four techniques (Winograd, Frost, Zadik, and Kaplan) have been interwined into the two modifications commonly used today. By following the step-by-step surgical method presented and adding the reader's own successful techniques, a good surgical result can be easily achieved.

Humans↗
PubMed1986

Effects of a low phosphorus, low nitrogen diet supplemented with essential amino acids and ketoanalogues on serum triglycerides of chronic uremic patients.

The effects were studied of a vegetarian low-protein, low-phosphorus diet supplemented with essential amino acids and ketoanalogues and those of maintenance hemodialysis (MHD) and free diet on the serum triglycerides (STG) of 85 patients with chronic renal failure. Following dietary therapy STG decreased significantly in the 61 male patients (from 185.7 +/- 89.8 to 153.5 +/- 68.7 mg/dl; p less than 0.001), whereas in the females the decrease was not significant (from 189.1 +/- 83.9 to 167.0 +/- 62.2 mg/dl; NS). When patients changed to MHD therapy and free diet STG increased again. We can conclude that the correction of hypogonadism of chronic male uremics largely accounts for the improvement of hypertriglyceridemia, though other factors are likely to contribute.

Adult↗
PubMed1982

Human tissue distribution of platinum after cis-diamminedichloroplatinum.

Using X-ray fluorescence spectrometry, platinum concentrations were determined in autopsy tissue samples from 12 patients who had received cis-diamminedichloroplatinum (DDP) 20-120 mg/m2 up to 6 months antemortem. Tissue platinum concentrations were highest in liver (0.5-3.7 micrograms/g wet weight), prostate (1.6-3.6 micrograms/g), and kidney (0.4-2.9 micrograms/g), somewhat lower in bladder, muscle, testicle, pancreas, and spleen, and lowest in bowel, adrenal, heart, lung, cerebrum, and cerebellum, Platinum concentrations in tumors were generally somewhat lower than the concentration in the organ in which the tumor was located, with the exception of intracerebral tumors. Different metastatic sites in the same patient had substantially different platinum concentrations and hepatic metastases had the highest concentrations. Intra-arterial administration of drug may augment tissue concentrations of platinum. In a patient undergoing therapeutic abortion 4 days after treatment, the platinum concentration was 0.5 micrograms/g in the placenta and 0.3 micrograms/g in the fetus. The data suggest that for in vitro sensitivity testing, DDP concentrations of less than or equal to 7 micrograms/ml should be used.

Autopsy↗