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Biomedical subjects

M Surian

Publications and source records attributed to M Surian.

At least 19 recordsLinked to original sources

Effect of chronic intravenous calcitriol on parathyroid function and set point of calcium in dialysis patients with refractory secondary hyperparathyroidism.

This study evaluates the effect of intravenous calcitriol on parathyroid function and ionized calcium-PTH sigmoidal curve obtained during low- and high-calcium haemodialysis in 10 patients with osteitis fibrosa whose secondary hyperparathyroidism was refractory to conventional therapy. After 4 months of intravenous calcitriol, serum ionized calcium increased from 1.28 +/- 0.08 to 1.37 +/- 0.11 mmol/l (P less than 0.001), serum phosphate from 1.54 +/- 0.18 to 1.79 +/- 0.4 mmol/l (P NS), serum calcitriol from 16.7 +/- 9.9 to 34.3 +/- 6.4 pg/ml (P less than 0.001), while alkaline phosphatase decreased from 366 +/- 340 to 226 +/- 180 IU/l (P less than 0.05), osteocalcin from 46.4 +/- 20 to 34.5 +/- 15.3 ng/ml (P less than 0.05), and basal intact PTH from 1069 +/- 700 to 305 +/- 270 (P less than 0.01). Basal PTH started to decrease after 1 month of treatment prior to the increase in the ionized calcium. Because of hypercalcaemia the dialysate calcium was decreased from 1.75 to 1.5 mmol/l in three of five patients on haemodialysis, and calcium-containing solutions were replaced by calcium-free fluids in four of five patients on haemodiafiltration. Calcitriol dose, at the first month of therapy was 5.6 +/- 0.8 micrograms/week, but it was successively decreased because of hypercalcaemia to a final dose of 3.6 +/- 1.3 micrograms/week. After intravenous calcitriol the ionized calcium-PTH sigmoidal curve shifted to the left and downward. Maximally stimulated PTH and maximally inhibited PTH obtained during low- and high-calcium dialysis significantly decreased, as well as the ratio of basal PTH/PTHmax and the set point of calcium.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcitriol

Peritoneography and peritoneal computerized tomography: a new approach to non-infectious complications of CAPD.

The introduction of the contrastographic medium (PG) eventually combined with CT scan (PCT) has been used in the study of non-infectious abdominal complications of patients on CAPD. In 27 patients on CAPD from 0 to 98 months we infused, through the peritoneal catheter, 100-200 ml of iopamidol and 500-2000 ml of peritoneal dialysis solution, effecting radiograms in different projections (27 cases), with contiguous axial scannings of 10 mm (8 cases). The information obtained was useful with regard to the therapeutic choices; it clarified the extent, the width, and the anatomical relations of hernias (7/7); the leakage site at the introduction point of the catheter (2/5), and site of surgical treatment (2/5); an inguinal hernia (1/4) and the previousness of the peritoneovaginal duct (3/4) in cases of the genital oedema; a displaced non-opaque catheter (1/4); obstruction of the terminal hole (2/4); wrapping of the omentum in a catheter malfunction (1/4); the presence of scar tissue and pathological recesses in the reduction of ultrafiltration (2/3); and the extension of secondary scar tissue after surgery and before CAPD was started. There were no infective complications or allergic reactions during the research. In conclusion, after reparative surgical intervention, PG and PCT are simple, convenient investigations, with significant diagnostic usefulness, before the introduction of the catheter and/or in cases of complications during CAPD.

Female

Effect of hemodialysis and hemodiafiltration on uremic neuropathy.

This study was undertaken to compare the effect of 1 year hemodialysis (HD) or hemodiafiltration (HDF) treatment on peripheral neuropathy. Thus 21 of 42 patients on chronic HD (1-1.3 m2 cuprophane dialyzer, Qb 300 ml/min) were switched to HDF (1.3 m2 polysulfone dialyzer, Qb 400 ml/min, substitution volume 9-13 liters, ultrafiltration rate 60-70 ml/min), while the remaining patients were considered as a control group. Treatment time was scheduled both in HD and HDF to maintain adequate BUN levels in relation to protein catabolic rate. However, HDF provided a significantly greater weekly inulin (MW 5,000) clearance than HD (5.8 +/- 1.2 vs. 1.6 +/- 0.2 ml/min; p less than 0.001). HD and HDF groups were comparable for age, time on dialysis and starting electroneurographic parameters, which were on average within the normal range. After 1 year follow-up, creatinine, hematocrit, calcium, phosphate, PTH, BUN, protein catabolic rate and residual GFR were comparable in the two groups, whereas beta 2-microglobulin was significantly reduced in HDF patients (29 +/- 6.7 vs. 38.8 +/- 13.9 mg/l in HD patients, p less than 0.01). During the 1-year treatment, electroneurographic parameters did not change in HDF patients, whereas a significant decrease of ulnar motor nerve conduction velocity, ulnar muscle action potential amplitudes, median sensory nerve conduction velocity and peroneal muscle action potential amplitudes was detected in HD patients. We conclude that HDF might prevent the worsening of the electroneurographic indices occurring during chronic HD treatment, as it provides a more effective removal of middle and larger molecules than HD. The use of a more biocompatible membrane in HDF might further contribute to this favorable effect on uremic neuropathy.

Adult

Ionised calcium changes and parathyroid hormone secretion in haemodiafiltration in relation to substitution fluid calcium content.

This study was carried out to evaluate the acute effect of either 1.75 mmol/l calcium (A-HDF) or bicarbonate-containing and calcium-free (B-HDF) substitution fluid on calcium balance, serum ionised calcium, and intact parathyroid hormone (PTH) during haemodiafiltration (HDF: 1.3 m2 polysulphone dialyser; blood flow rate, 400 ml/min; treatment time 210 min; substitution fluid volume, 10 litres; dialysate calcium, 1.75 mmol/l). During A-HDF calcium balance was slightly positive (1.47 +/- 2.95 mmol), serum ionised calcium increased from 1.24 +/- 0.08 mmol/l to a final 1.46 +/- 0.05 mmol/l at the end of the treatment (P less than 0.001), and PTH decreased from 227 +/- 231 pg/ml to 150 +/- 123 pg/ml (P less than 0.01), during B-HDF calcium balance was negative (-3.06 +/- 1.3 mmol), ionised calcium decreased from 1.29 +/- 0.05 to 1.24 +/- 0.05 mmol/l (P less than 0.05) without inducing a statistically significant increase in PTH. However, in some patients the increase in PTH after treatment was greater than 50%. When the ultrafiltration rate was increased to 75-100 ml/min and bicarbonate-containing and calcium-free replacement fluid was used (B2-HDF), calcium balance became more negative (-9.75 +/- 4.55 mmol) and the decrease of ionised calcium was greater (from 1.3 +/- 0.06 to 1.14 +/- 0.04 mmol/l, P less than 0.01) inducing a significant increase of PTH (from 297 +/- 366 to 443 +/- 518 pg/ml, P less than 0.01). PTH changes were negatively correlated (r = -0.85) to ionised calcium changes during the treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Bicarbonates

Morphological, immunohistological and clinical findings in renal amyloidosis: correlations with prognosis in 16 patients.

Sixteen patients affected by renal amyloidosis (A.) and submitted to renal biopsy have been studied by light microscopy and immunofluorescence. Clinical manifestations at observation and follow up have been reviewed. Survival was 32% at ten years, lower than all other nephropathies except rapidly-progressive glomerulonephritis. Primary A. had a significantly worse survival rate than secondary A. An observation up to 6 years after biopsy allowed us to isolate a group of patients with a steady good renal function: this group is characterized by: a longer mean duration of nephropathy before observation, a lower incidence of nephrotic syndrome (NS), absence of renal failure at time of biopsy, a higher incidence of increased mesangial areas at light microscopy, a lower percentage of glomerular capillary walls thickening, a higher incidence of amyloid deposits on vessels but not on glomerular capillaries, a definite more elevated presence of Ig and C3 over mesangium and glomerular capillary walls. The possible role of the last findings is discussed.

Adolescent

Thiazide diuretics in renal hypercalciuria.

Forty-six renal hypercalciuric normocalcaemic patients were treated with hydrochlorothiazide (50mg/day) and amiloride (5 mg/day), both to reduce new stone formation and to suppress parathyroid hyperfunction. A reduction of hypercalciuria and suppression of parathyroid hyperactivity were observed in 41 patients, while in the other five patients no evidence of parathyroid suppression was found and hypercalcaemia developed. Four of five patients underwent parathyroidectomy which was followed by a normalisation of biochemical signs of hyperparathyroidism. These results suggest that the appearance of hypercalcaemia in renal hypercalciuric patients during hydrochlorothiazide/amiloride treatment may be of diagnostic value in unmasking pharmacologically non-suppressible normocalcaemic hyperparathyroidism.

Adult

[Treatment with antilymphocyte globulin (ALG) and evolution of renal transplant: observations of 42 cases].

42 necrokidney transplants, performed in Renal Unit of "Niguarda - Ca' Granda" Hospital in Milan, since 1972, have been examined. Hystocompatibility score and previous transfusions and/or pregnancies apparently did not correlate with three months transplants survival. Our patients have been separated into two groups according to treatment with or without ALG: the group treated with ALG showed a better percentage survival of the kidney at three months a lower incidence of rejection episodes during the same period. The usefulness of ALG treatment is reaffirmed; we consider that a better prognosis at three months probably means a more favorable clinical course.

Adolescent

[Immunohistological aspects of nephropathy with minimal lesions].

Renal biopsies from 32 patients, whose light microscopy showed a pattern of minimal changes nephropathy, have been submitted to immunohistological examination. On the basis of immunofluorescence pattern we separated the cases into three groups: the first group (12 cases) was characterized by absence of any glomerular deposit. The second group (9 cases) showed focal and segmental deposits of IgM and sometimes C3 on capillary walls. In the third group (11 cases) we observed slight deposits of IgM and sometimes C3 "comma like" over glomerular structures in all glomeruli. The site of these last deposits was sometimes mesangium and sometimes the capillary walls. The results of immunohistological examinations gave no information about the pathogenetic mechanisms of minimal changes nephropathy. We observed that the patients enclosed in the second group had a worse clinical prognosis, compared with the other two groups.

Capillaries

Acute renal failure due to rifampicin (R-ARF).

Five episodes of acute renal failure due to rifampicin (R-ARF) were observed in four patients and the clinical and histological data were compared with the records of 52 episodes reported in the literature. The bulk of data supports the assumption that the by far most frequent renal injury responsible for R-ARF is acute tubular necrosis produced by a vasomotor mechanism. Nevertheless a few data, above all immunohistological findings, suggest the local presence of allergic process. It may be, that the development of an immunological renal lesion is prevented or blunted by the consequences of vasomotor effects.

Acute Kidney Injury

Fluorine concentrations in bone biopsy samples determined by proton-induced gamma-ray emission and cyclic neutron activation.

Fluorine concentrations in bone biopsy samples taken from the iliac crest of subjects, divided into four groups depending on the length of dialysis treatment, and aluminium levels in blood and bone pathology, in terms of osteoporosis, were determined by two instrumental methods. Proton-induced gamma-ray emission (PIGE), making use of the resonance reaction of 19F(p, alpha gamma)16O at 872 keV, and cyclic neutron activation analysis (CNAA), using the 19F(n, gamma)20F reaction in a reactor irradiation facility, were employed. Rutherford backscattering (RBS) was used to calculate the volume, and, hence, mass of the sample excited in PIGE by determining the major element composition of the samples in order to express results in terms of concentration. From this preliminary investigation, a relationship is suggested between fluorine concentrations in bone and aluminium levels in the system.

Aluminum