Search PubMed⌕ Search

Biomedical subjects

E Bonucci

Publications and source records attributed to E Bonucci.

At least 55 records · Page 3Linked to original sources
PubMed1995

Metabolic acidosis and osteodystrophic bone disease in predialysis chronic renal failure: effect of calcitriol treatment.

The role of metabolic acidosis on osteodystrophic bone lesions of chronic renal failure has been studied retrospectively in 24 patients, divided into two equal groups of 12, one with normal acid-base equilibrium (group A) and one with metabolic acidosis (group B). The two groups were found to differ significantly in serum levels of BGP (23.7 +/- 18 vs. 42.3 +/- 24 ng/ml, p < 0.02) and in several bone histomorphometric parameters such as osteoid volume (4.5 +/- 3.4 vs. 10.2 +/- 6.6%, p < 0.01), osteoid surface (27.7 +/- 18 vs. 48.4 +/- 19%, p < 0.01), single-labelled surface (7.94 +/- 2.9 vs. 15.8 +/- 9.9%, p < 0.02), mineralizing surface (60.69 +/- 26 vs. 30.89 +/- 15.8%, p < 0.003) and mineralization lag time (56.5 +/- 54 vs. 170.5 +/- 189 days, p < 0.05), with the acidotic group showing excess osteoid and a defect in mineralization. Osteomalacia was found only in the acidotic group, while the only 2 cases of adynamic bone disease (ABD) were in the nonacidotic group. Calcitriol administration, 0.25 micrograms daily for a period of 1 year, in 5 cases in group A and 6 cases in group B induced significant improvement of bone lesions mainly in group A. Two of these patients following treatment acquired the characteristics of ABD. In group B, the response to treatment was very limited, with 5 patients still showing persistence of the histological mixed type of bone disease. In conclusion, metabolic acidosis is accompanied by osteomalacia, pure or mixed variety, and shows a relative resistance to calcitriol administration. Normal acid-base equilibrium is more frequently associated with mild hyperparathyroidism and ABD, spontaneously or as a consequence of calcitriol administration.

Acid-Base Equilibrium↗
PubMed1994

Morphological studies of hypomineralized enamel of rat pups on calcium-deficient diet, and of its changes after return to normal diet.

BACKGROUND: Micro-hardness investigations have shown that rat pups nursed by mothers on a low calcium diet and weaned with the maternal calcium-deficient diet develop hypomineralized enamel. The inorganic and organic components of this enamel, their relationships, and their changes after return to normal diet have been studied by light and electron microscopy. METHODS: The maturation zone of incisor enamel has been studied in: (1) rats nursed for 20 days by mothers on a low calcium diet and weaned for 30 days with the same diet (E1 enamel); (2) rats that after the calcium-deficient diet were fed normal diet for 10 days (E2 enamel); and (3) rats nursed for 20 days by mothers on a normal diet and weaned for 30 days with a normal diet (controls). RESULTS: The results showed that E1 enamel was hypomineralized, as noted by its Azure II-Methylene blue stainability in undecalcified sections, its light staining with the von Kossa method, and its ultrastructure. E1 crystallites, although present throughout the whole enamel, were thinner than those of E2 enamel, which were similar to those of controls. E1 interrod crystallites were thicker in the intermediate than in the dentinal zone and were thicker than rod crystallites. Organic matrix was present throughout the whole E1 enamel. Its organic components (crystal ghosts) had the same shape, arrangement, and organization as those of inorganic crystallites. Crystal ghosts were greatly reduced in E2 enamel and in controls. CONCLUSIONS: The results lead to the conclusions that: (1) E1 enamel is hypomineralized, and its degree of calcification is restored by return to a normal calcium diet; (2) intra- and interprismatic calcification occurs in a different way; (3) crystallite thickness is initially greater in dentinal than in the superficial zone and is reversed as crystallite growth is completed; and (4) loss of enamel proteins is necessary for completion of crystallite growth and not for crystallite formation.

Animal Nutritional Physiological Phenomena↗
PubMed1994

Evidence of healing of secondary hyperparathyroidism in chronically hemodialyzed uremic patients treated with long-term intravenous calcitriol.

The aim of this study was to assess the effect of a long-term course of high-dose i.v. pulses of calcitriol (CLT) on hyperparathyroid bone disease (HBD) and functional mass of parathyroid glands of chronically hemodialyzed uremic (CHU) patients. We prospectively studied nine CHU patients treated with CLT, 30 ng/kg/body wt, i.v., thrice weekly over a period of eight months. Plasma concentrations of intact parathyroid hormone (iPTH), bone GLA protein (bGLA) and bone isoenzyme of alkaline phosphatase (biALP) were sampled throughout. Transiliac bone biopsies were made before and after the start of CLT therapy. Double scanning scintigraphy of the neck with 201Tl-99Tc was made before, during and eight months after the start of the treatment. All patients but one, who later responded to higher than planned CLT doses, had significant decreases of plasma iPTH (F = 76; P < 0.0001; ANOVA). The mean pretreatment value of PTH was 966 +/- 160 (mean +/- SE) pg/ml and it had decreased significantly by the first week (T = 2.4, P < 0.04), and had fallen an average of 80% by the 35th week. Ionized plasma calcium concentration was 1.19 +/- .01 mmol/liter which rose significantly (F = 13.5; P < 0.0001) by the 14th week to maximal peak levels, averaging 1.34 +/- .02 mmol/liter. Changes in biALP were parallel to those of iPTH, while bGLA tended to increase immediately after the start of the therapy and to significantly decrease thereafter (T = 3.2; P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Intravenous versus oral calcitriol therapy in renal osteodystrophy: results of a prospective, pulsed and dose-comparable study.

Intravenous calcitriol is generally considered to be more efficient than oral administration in the treatment of secondary hyperparathyroidism of chronic renal failure, although a comparative and prospective study employing the same doses and modality of drug administration is lacking. We therefore evaluated 12 hemodialysis (HD) patients (51.7 +/- 9.4 years, mean +/- SD, HD for 8.7 +/- 4.7 years) with marked secondary hyperparathyroidism. Based on basal humoral and bone histologic parameters, we divided these patients into 2 comparable groups. Calcitriol (0.015 micrograms/kg) was given at the end of each dialysis intravenously in group A and orally in group B. Humoral parameters were evaluated basally and after 1, 2, 4 and 8 months. Ax bone biopsy was taken at the start and at the end of the study. From the first month of treatment, group A showed an increment in ionized calcium (from 1.28 +/- 0.08 to 1.37 +/- 0.12 mmol/l, p < 0.01), with a reduction in intact parathyroid hormone (from 470.1 +/- 349.5 to 255.5 +/- 256.5 pg/ml; p < 0.0003) and alkaline phosphatase (from 615.1 +/- 696.3 to 445.3 +/- 577.7 mU/ml, p < 0.001). The occurrence of hypercalcemia prompted a reduction in dialysate calcium content in 4 of 6 patients after 4 months, and of the calcitriol dose in 2 of 4 patients after 6 months. Ionized calcium then turned to 1.32 +/- 0.11 (p = n.s. compared to basal) while the intact parathyroid hormone concentration tended to revert (363.3 +/- 360 pg/ml, p = n.s. compared to basal) and alkaline phosphatase remained low (420 +/- 638 mU/ml, p < 0.0005).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1993

Culture and differentiation of chondrocytes entrapped in alginate gels.

We studied the response to culture conditions and the differentiative ability in suspension culture in alginate gels of resting chondrocytes from the preosseous cartilage of adult pig scapula. It was found that the maximum rate of chondrocyte duplication is reached at the fourth day in culture whereas the rate of proteoglycan synthesis and alkaline phosphatase expression do not gain a maximum value before the seventh day. During the culture time, the chondrocytes undergo differentiation as it is demonstrated by the alkaline phosphatase specific activity increase and by morphological criteria (hypertrophy, increase of the number of mitochondria per cell, increased endoplasmic reticulum, matrix vesicle production). The alginate gels can be easily dissolved to obtain cell populations in which the variation of cytosolic calcium concentration following a proliferative stimulus can be conveniently observed using the conventional procedure of Fura 2.

Alginates↗
PubMed1993

Long-term survival on renal replacement therapy for primary hyperoxaluria type I.

We describe the case of a patient in end-stage renal failure due to primary hyperoxaluria type I (PH1) who started hemodialysis in 1977 and is still alive and active. The diagnosis of PH1 was first suspected after a bone biopsy performed in 1981 to investigate hyperparathyroidism. Oxalosis recurred as early as 3 months after transplantation in a cadaver kidney grafted in 1987; nevertheless, graft function remained good enough to make possible the discontinuation of dialysis treatment for 5 months and thereafter to have only 1 dialysis a week for 17 months. The diagnosis of PH1 has been recently confirmed despite the patient being already anuric by means of the determination of plasma oxalate and glycolate levels as well as by determining hepatic alanine:glyoxylate amino-transferase.

Adult↗
PubMed1993

Dynamics of bone aluminum over one year of functioning renal graft.

The concentration of aluminum (Al) in serum, urine, and bone, as well as bone histomorphometry parameters were studied before and 1 year after kidney transplantation (Tx) in 20 dialyzed patients. One year after Tx, serum Al fell significantly from 50.3 +/- 8.8 to 23.9 +/- 2.7 micrograms/l, (53% fall). Bone Al content also decreased significantly from 62.9 +/- 9.0 to 36.5 +/- 7.0 micrograms/kg bone weight, but urine Al excretion was still above normal. The repeat bone histomorphometric examination showed a good recovery of bone resorption which correlated well with serum parathyroid hormone levels, but poorer recovery of indices of bone formation and of the extent of Al deposits in the bone as shown by aluminum staining.

Adult↗
PubMed1993

Bone sialoprotein (BSP) secretion and osteoblast differentiation: relationship to bromodeoxyuridine incorporation, alkaline phosphatase, and matrix deposition.

We defined two distinct maturational compartments (proliferative and secretory) of osteogenic cells in vivo on the basis of ALP activity, BrdU incorporation, cell shape, and BSP production. BSP immunoreactivity was found to mark cells in the secretory but not in the proliferative compartment. We established the phenotypic similarity of primitive marrow stromal cells with proliferating perichondral cells (fibroblast-like, ALP+, BrdU+, BSP-). This suggests the potential functional equivalence of the two cell types as committed non-secretory osteogenic cells and points to the duality of osteogenic cell compartments as a generalized feature of bone formation. We further showed that although BSP secretion is a hallmark of the onset of osteogenesis, BSP antigenicity is lost both in osteoid and in a large proportion of mature osteoblasts during subsequent phases of bone deposition. This suggests that bone formation may not be a uniform event, as bone cells actually deposit antigenically, and likely biochemically, distinct matrices at specific times.

Alkaline Phosphatase↗
PubMed1993

Localization of bone sialoprotein (BSP) to Golgi and post-Golgi secretory structures in osteoblasts and to discrete sites in early bone matrix.

Bone sialoprotein (BSP), a bone matrix-enriched glycoprotein containing the Arg-Gly-Asp (RGD) motif and endowed with cell binding properties, was localized in osteoblasts and early bone matrix of developing rat bone at the ultrastructural level. Preliminary light microscopic observations indicated that intracellular labelling was restricted to a paranuclear dot corresponding to the "negative Golgi image" of classical histology. The same pattern was observed whether antisera against the fully glycosylated protein or a peptide antiserum to a stretch of amino acids in human BSP sequence were employed. At the EM level, we obtained labeling over the Golgi area of osteoblasts but not over the rER. The labeling was concentrated over distensions of the trans Golgi and over pro-secretory granules. In the matrix, BSP was distributed in a non-random manner. The label was concentrated over spherical aggregates of finely fibrillar material corresponding to the sites of early mineral deposition (so-called "mineralization nodules"). Such BSP-positive foci were seen both close to and away from the cell surface. The predominant association of BSP with Golgi and post-Golgi secretory structures and its absence from rER, as well as the reproducibility of the same pattern of localization with different antisera, might indicate a slow transit of the protein through the Golgi, not necessarily associated with protein glycosylation.

Amino Acid Sequence↗
PubMed1993

Two-site immunoradiometric intact parathyroid hormone assay versus C-terminal parathyroid hormone in predicting osteodystrophic bone lesions in predialysis chronic renal failure.

Intact parathyroid hormone (iPTH) radioimmunoassay represents an important advancement in the measurement of serum PTH levels, permitting the evaluation of the actual rate of secretion of the parathyroid glands. The aim of the study was to compare the value of intact and C-terminal PTH measurements in predicting the osteodystrophic bone lesion in predialysis patients with chronic renal failure (CRF). We have studied 37 subjects with CRF who were receiving conservative treatment. In each subject a transiliac bone biopsy for histomorphometric examination was performed in addition to the assay of serum intact and C-terminal PTH, osteocalcin, and alkaline phosphatase. Serum C-terminal and intact PTH levels were closely correlated, both showing a high degree of correlation with serum osteocalcin. Similar degrees of correlation were observed between the two PTH assays and the histologic parameters osteoblastic surface (ObS/BS) and osteoclastic surface (OcS/BS). The evaluation of specificity and sensitivity of the two PTH assays in selecting patients with normal or pathologic histomorphometric parameters gave an equivalent number of false positive and negative cases. Based on discriminant analysis of histomorphometric parameters, intact PTH shows a higher discriminant power when compared with C-terminal PTH assay for the parameters OcS/BS and eroded surface (ES/BS), but without practical clinical value. In conclusion, in analogy to the short lived N-terminal PTH fragment assay, prediction of elementary hyperparathyroid bone lesions in predialysis CRF is not improved by the use of intact PTH as compared to the more traditional C-terminal assay.

Adult↗
PubMed1992

Extracellular alkaline phosphatase activity in mineralizing matrices of cartilage and bone: ultrastructural localization using a cerium-based method.

The ultrastructural localization of alkaline phosphatase (A1P) activity has been demonstrated in epiphyseal growth cartilage and metaphyseal bone of rats. Epiphyso-metaphyseal specimens were decalcified with EDTA and treated with MgCl2 to regenerate the enzymatic activity before incubation in a medium containing beta-glycerophosphate, MgCl2 and CeCl3. A1P activity was present on the outer surface of the plasmamembrane of maturing and hypertrophic chondrocytes and of osteoblasts. Moreover, the reaction product was present in chondrocyte lacunae, in matrix vesicles, and in cartilage matrix, as well as among uncalcified collagen fibrils of osteoid tissue in bone. The intensity of reaction was the lowest, or completely lacking, where the degree of matrix calcification was the highest. These results suggest that alkaline phosphatase is transported from the cells into the cartilage and bone matrix by its association with matrix vesicles and plasmamembrane components, and that its activity in cartilage and bone matrix is inhibited as it is incorporated in the mineral substance.

Alkaline Phosphatase↗
PubMed1992

Ipriflavone inhibits osteoclast differentiation in parathyroid transplanted parietal bone of rats.

Ipriflavone, a synthetic isoflavone-derived flavonoid, was shown to have inhibitory effect on bone resorption. In order to study its mechanism of action directly on bone, 46 female Wistar rats were divided into six groups and medicated orally for 25 days as follows: groups 1 and 2 were given 1% carboxymethylcellulose solution (vehicle), groups 3, 4, 5, and 6 were administered ipriflavone at doses of 0.178, 0.356, 0.712, and 1.424 mmol/kg/day (suspended in vehicle), respectively. On the 22nd day, parathyroid glands, taken from donor rats, were transplanted in contact with the outer surface of the periosteum of both the right and the left parietal bones of rats from groups 2, 3, 4, 5, and 6. The group 1 rats underwent sham operation. Bone histomorphometry, performed on the ectocranial periosteum of parietal bones, showed that absolute erosion boundary, absolute eroded area, absolute erosion depth, number of tartrate-resistant acid phosphatase (TRAP)-positive polynucleated osteoclasts, and number of TRAP-positive mononucleated cells decreased in ipriflavone-treated rats compared with group 2 rats. The reduction was roughly proportional to the increase of drug dosage and reached statistical significance in rats of groups 5 and 6. The same parameters were extremely low in group 1 rats. Mineral apposition rate did not differ in any of the groups. Significant increase of serum calcium and significant decrease of serum phosphate were found in group 2 rats compared with group 1 rats, whereas no differences from controls were detected in ipriflavone-treated animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Paramyxovirus-like nuclear inclusions identical to those of Paget's disease of bone detected in giant cells of primary oxalosis.

Nuclear inclusions, identical to those characteristic of Paget's disease of bone, were observed in giant cells in four of eight cases of primary oxalosis. The giant cells containing nuclear inclusions were directly involved in phagocytosis of large oxalate crystals in the context of typical foreign body granulomas in the bone marrow. Cytochemically, all of them exhibited strong tartrate-resistant acid phosphatase activity, and a proportion of them also tartrate-resistant acid ATPase. The inclusions consisted of typical arrays of filamentous material as described in Paget's disease, admixed with variable proportions of electron-dense material closely reminiscent of nucleolar pars fibrillaris and fibrillary centres. These data indicate: (a) the occurrence of Paget-like inclusions in a bone disease unrelated to Paget's disease, not causally related to viral infection, and resulting from an inborn metabolic derangement; and (b) the occurrence of Paget-like inclusions in foreign body giant cells as opposed to osteoclasts. We suggest that the occurrence of paramyxovirus-like nuclear inclusions in either osteoclasts or giant cells may represent an epiphenomenon of cell fusion and giant cell formation whenever appropriate stimuli act on latently infected precursor cells. Furthermore, our data suggest that nucleoli may represent the specific site of virus-like inclusion formation.

Acid Phosphatase↗
PubMed1992

Cytological and ultrastructural investigation on osteoblastic and preosteoclastic cells grown in vitro in the presence of ipriflavone: preliminary results.

The effects of ipriflavone on bone cells were studied in vitro on pre-osteoclastic (FLG 29.1) and osteoblast-like (Saos-2) cells grown for 48 h either separately or in co-cultures, with or without the addition of PTH. Histological, ultrastructural and histochemical (TRAP-activity demonstration) methods were used. The main results show that ipriflavone reduces replication of FLG 29.1 cells and inhibits TRAP production by these cells both in controls and in co-cultures treated with PTH. Moreover, it has a moderate stimulatory effect on proliferation of osteoblast-like cells and reduces the PTH-induced degenerative changes of Saos-2 cells. These results suggest that the inhibitory effect of ipriflavone on FLG 29.1 cells might be indirect and might be mediated by the osteoblast-like cells.

Acid Phosphatase↗
PubMed1992

Ultrastructural localization of alkaline and acid phosphatase activities in dental plaque.

Ultrastructural cytohistochemical techniques showed presence of acid and alkaline phosphatases in dental plaque. Both phosphatases had intra- and extramicrobial localization. In the extracellular matrix, phosphatases were associated with small vesicles of bacterial origin, or were freely scattered in the matrix without apparent connection with microbial structures. Intracellularly, alkaline (AlkP) and acid (AcP) phosphatases were observed in Gram-negative and Gram-positive bacteria, showing a different localization. The AlkP was mainly located in the periplasmic space, while AcP had a double preferential localization: along the outer surface of the cell wall and in the periplasmic space. Less frequently an intracellular phosphatase reaction was seen in the cytoplasm.

Acid Phosphatase↗
PubMed1992

Procollagen type I C-terminal extension peptide in predialysis chronic renal failure.

Collagen type 1 is the most abundant protein of bone. Serum levels of type 1 procollagen carboxy-terminal extension peptide (Procoll-1-C) may give a measure of the rate of synthesis of the collagen of bone and be therefore a marker of bone turnover. We have studied 38 patients with predialysis chronic renal failure; 14 of them were under long-term treatment with 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] for prevention of secondary hyperparathyroidism. In all patients a transiliac bone biopsy for histomorphometry and determination of dynamic parameters was performed following double tetracycline labeling. In addition serum Procoll-1-C, intact and C-terminal parathyroid hormone (PTH), osteocalcin and alkaline phosphatase were determined. In the patients not receiving 1,25(OH)2D3, serum levels of Procoll-1-C were higher than normal. Procoll-1-C did not correlate with any of the humoral parameters, including serum creatinine, nor with static histomorphometric parameters. Contrarily to osteocalcin, the collagen type 1 marker correlated significantly with all dynamic parameters. Treatment with 1,25(OH)2D3 was accompanied by lower levels of osteocalcin, iPTH (n.s.), osteoblastic surface and by normal levels of Procoll-1-C (p < 0.001, compared to untreated patients), without substantial change in bone formation parameters (bone formation rate). In conclusion Procoll-1-C in predialysis chronic renal failure is a marker of bone turnover unparalleled by other markers. 1,25(OH)2D3 administration is associated with lower serum levels of the peptide unaccompanied by a decrement of bone formation parameters, therefore with an apparently better utilization of collagen type 1 in the mineralization process.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaline Phosphatase↗
PubMed1992

Neoplastic infiltration of laryngeal cartilages: histocytochemical study.

The relationship between cartilage and invading neoplastic cells was studied in 32 cases of laryngeal cancer by histological and cytochemical methods. Cartilage invasion was present in 12 cases, 10 of which were in proximity or in contact with areas of calcification and ossification. It was significantly correlated only to tobacco consumption (P less than .05) and, in regard to glottic tumors, to tumor diameter greater than 3 cm (P less than .01). Histologically, neoplastic invasion in cartilage was massive in 2 cases, occurred in areas of ossification in 4, between cartilage and bone in 4, and in epiglottic cartilage in 2. In 3 of the cases with bone invasion, there was also new bone formation. Hyaline cartilage and bone resorption was due to tartrate-resistant acid phosphatase (TRAP)-positive giant cells; in epiglottic cartilage only mononuclear cells were present, some of which were TRAP-positive. These results show that neoplastic cells can promote not only resorption and formation of bone, but also resorption of cartilage, which is considered resistant to neoplastic invasion. The different types of resorbing cells in contact with hyaline cartilage and bone in laryngeal cancer, and elastic cartilage in epiglottic cancer, suggest that the structure of the tissue being resorbed can influence the type of resorbing cells.

Acid Phosphatase↗