Biomedical subjects

E Bonucci

Publications and source records attributed to E Bonucci.

At least 37 records · Page 2Linked to original sources

PubMed1997

Tartrate-resistant acid phosphate activity as osteoclastic marker: sensitivity of cytochemical assessment and serum assay in comparison with standardized osteoclast histomorphometry.

Tartrate-resistant acid phosphatase (TRAP) activity is regarded as an important cytochemical marker of osteoclasts; its concentration in serum is utilized as a biochemical marker of osteoclast function and degree of bone resorption. This study was carried out to assess the sensitivity of TRAP activity both as a cytochemical marker in histological sections and as a biochemical marker in serum in comparison with the standardized histomorphometric variables of osteoclasts. To this end we investigated 24 patients (21 women, 3 men; 60 +/- 17 years of age) affected with various metabolic bone diseases. Osteoclast surface (OcS/BS) and osteoclast number (OcN/BS) were evaluated by standardized histomorphometry in iliac crest biopsies. On the basis of TRAP cytochemical activity, TRAP-positive osteoclast surface (TRAP + OcS/BS) and number (TRAP + OcN/BS) were measured. TRAP-positive cells adjacent to bone and showing one nucleus or no nuclei at all in the plane of section were included in the counts as osteoclasts. Serum TRAP activity was determined by spectrophotometric assay. Values of OcS/BS and OcN/BS were much lower than those of TRAP + OcS/BS (-50%) and TRAP + OcN/BS (-60%), respectively. Correlations between OcS/BS and TRAP + OcS/BS, and between OcN/BS and TRAP + OcN/BS, were highly significant. Serum TRAP was significantly correlated with OcS/BS, OcN/BS, and TRAP + OcN/BS. These correlations, however, were rather low. Moreover, serum TRAP did not correlate with TRAP + OcS/BS. From these results, the conclusion can be drawn that while TRAP activity is confirmed as a valid cytochemical marker for identification of osteoclasts, serum TRAP activity is an osteoclastic marker of weak sensitivity. This may be due to known factors, such as synthesis of the enzyme not being unique to osteoclasts, enzyme instability, and the presence of inhibitors in serum. Mononucleated osteoclasts do not significantly influence the serum enzyme levels.

Acid Phosphatase↗

PubMed1997

Long-term results of hydroxyapatite-fibrin glue implantation in plastic and reconstructive craniofacial surgery.

The bone tissue formed in orthotopic or heterotopic implants of granular, porous hydroxyapatite and fibrin glue was examined several (2 1/2-8) years after implantation. The results showed distinct ossification in all cases and the functional situation and external appearance were also satisfactory. The reconstituted spongy and compact bone underwent a remodelling process similar to that of normal bone. Most of the hydroxyapatite granules were embedded in the bone tissue; a few were very close to the fibrillar connective tissue of the intertrabecular spaces and were either covered by osteoid-like collagenous borders or were in contact with osteoclast-like giant cells. Even if the results refer only to a few patients, and were obtained from a cross-sectional study, they allow the conclusion to be reached that the implantation of porous hydroxyapatite and fibrin glue leads to the formation of long-lasting bone whose hardness is equal to, or greater than, that of normal bone.

Adult↗

PubMed1997

Relative roles of intestinal absorption and dialysis-fluid-related exposure in the accumulation of aluminium in haemodialysis patients.

BACKGROUND: A recent retrospective study has clearly demonstrated a reduction of cases with positive bone aluminium (Al) staining in the Italian dialysis population, which in general has had a low prevalence of bone Al toxicity. In the present study we tried to better address the relative role played, in our study population, by enteral and parenteral exposure to Al in reducing bone accumulation. METHODS: We retrospectively examined the data of 105 DFO tests and bone Al determinations performed in dialysis patients from 1984 to 1995. Enternal exposure was analysed by accurate anamnestic records, while parenteral exposure was evaluated by the determination of Al content in dialysis fluids. Bone Al content was assayed chemically and histochemically, while serum Al was assayed spectrophotometrically. Data pertinent to the patients were allotted into three period groups: 1984-1987; 1988-1991; 1992-1995. As for Al concentrations in dialysis fluids, the interval 1980-1983 (immediately before the start of our study), which could clearly have influenced bone Al content, was also considered. RESULTS: Basal serum Al showed some fluctuations (42.7 +/- 34.1; 24.8 +/- 21.9 and 38.9 +/- 34.9 micrograms/l respectively in the three groups, ANOVA P < 0.01) but only values of the period 1988-1991 were significantly lower than those of the period 1984-1987 (P < 0.05). Increments after DFO did not differ in the three periods (136.5 +/- 105.7; vs 98.7 +/- 91.7 and 106.1 +/- 96.2 micrograms/l respectively, P = n.s.). Enteral exposure to drugs containing Al was comparable (4.1 +/- 2.9 vs 4.0 +/- 4.6 and 5.8 +/- 7.9 total kg ingested respectively; P = n.s.), but bone Al was dramatically reduced (from 60.7 +/- 43.0 to 29.0 +/- 24.4 and 31.9 +/- 29.9 mg/kg/dw respectively; P < 0.0001), along with the definite disappearance of Aluminon-positive cases and Al-related bone disease (ARBD) after 1991. Parenteral exposure through the dialysate dropped from a mean of 26 +/- 14 micrograms/l in the 4-year period prior the start of the study (1980-1983) to 9 +/- 6 micrograms/l in the period 1984-1987 and to 4.9 +/- 2.1 micrograms/l and 5.0 +/- 2.0 micrograms/l respectively thereafter (P < 0.0001). CONCLUSIONS: Despite the persistence of oral exposure to Al, responsible for the observed stability of serum Al levels, a definite reduction of bone Al content has been recorded in our dialysis population, and ARBD has disappeared. This result has to be referred essentially to the optimal control of Al content in dialysis fluids, which is confirmed as a major factor for Al intoxication.

Adult↗

PubMed1997

Osteogenic response to hydroxyapatite-fibrin implants in maxillofacial bone defects.

Bone formation in hydroxyapatite-fibrin implants has been reported several times. However, available studies refer to experimental animals, or are limited to short periods after implantation. We report the results of histological, histochemical and ultrastructural studies carried out 2.5-8 yr after implantation of non-resorbable, porous hydroxyapatite (HA) and fibrin glue in human maxillofacial bones. Prominent ossification was found in all cases, with the presence of normally structured spongy bone. HA granules were embedded in the calcified bone matrix. They had not elicited inflammatory reactions and did not induce bone resorption. Ossification was preceded by the appearance of alkaline phosphatase activity on fibroblast-like cells, and by the formation of dense collagenous layers, similar to osteoid borders, on the surface of HA granules. The early phases of the calcification process occurred in these borders, with the appearance of calcification nodules adjacent to alkaline phosphatase-positive osteoblast-like cells. A remodeling process similar to that occurring in normal bones was found in the newly formed bone. These results justify the conclusion that HA-fibrin implants lead to the formation of long-lasting bone that does not differ from that of the normal maxillofacial skeleton. Mixing the HA granules with fibrin has the advantage of creating an easily mouldable material which can be adapted to any skeletal surface and stays in place after surgery.

Alkaline Phosphatase↗

PubMed1997

MC22-33F monoclonal antibody shows unmasked polar head groups of choline-containing phospholipids in cartilage and bone.

The importance of the role lipids may have in biological calcification, and the paucity and poor specificity of the methods available for studying their ultrastructural localization, call for further investigations involving new techniques. The monoclonal antibody MC22-33F displays a specific reaction with phosphatidylcholine, sphingomyelin and dimethylphosphatidylethanolamine, as confirmed by its reaction with synthetic lyposomes of pure phosphatidylcholine. For this reason, it was used to demonstrate the presence and ultrastructural localization of choline-containing phospholipids in calcifying cartilage and bone. The MC22-33F MAb immunoreaction was found in the cytoplasm of maturing and hypertrophic and, to a lesser extent, proliferating and degenerating chondrocytes; it was strongly positive in matrix vesicles, at the periphery of calcification nodules, and at the periphery of calcified matrix. In bone, the immunoreaction was especially strong along the peripheral membrane of the osteoblasts, in the interfibrillary spaces of the osteoid border, in matrix vesicles and in the peripheral zone of the calcification nodules. The central zone of the nodules, the fully calcified matrix and most of the intracellular membranes were negative in both cartilage and bone. These results confirm the presence of choline-containing phospholipids in early areas of calcification, including matrix vesicles. They also show that the intracellular membrane phospholipids are not accessible to the antibody, possibly because they are masked by other substances. These are not proteoglycans, because their enzymatic digestion does not increase or modify the reactivity of MC22-33F MAb. In spite of this limitation, MC22-33F MAb offers considerable advantages in the study of the calcification process, because the positive immunoreaction of the calcifying bone matrix, and the negativity of calcified matrix, confirm without doubt that phospholipids have an active role in biological calcification.

Animals↗

PubMed1996

Influence of specimen preparation on the identification of phospholipids by the phospholipase A2-gold method in mineralizing cartilage and bone.

The role of phospholipids in biological mineralization has been hypothesized but not fully elucidated. In order to identify phospholipids at the ultrastructural level in the mineralizing extracellular matrix, rat epiphyseal cartilage and metaphyseal bone have been labeled with the phospholipase A(2) (PLA(2))-gold method. The specificity and the efficiency of phospholipid detection have been evaluated by postembedding labeling of sections from epoxy- or hydrophilic resin-embedded samples, and by preembedding labeling of cryosectioned samples. The efficiency of the labeling was higher in cryosections than in hydrophilic resin-embedded specimens, while lower efficiency was found in epoxy resin-embedded samples. A 2- to 6-fold increase of the labeling density in calcified with respect to uncalcified areas of cartilage and bone has been found, depending on the specimen preparation used. The labeling intensity was significantly higher, at the periphery of the calcifying nodules in the epiphyseal cartilage matrix and in the calcifying osteoid, while the fully calcified bone matrix presented a weak labeling. Matrix vesicles, which are considered a possible source of extracellular phospholipids, appeared labeled in cryosections and in epoxy resin-embedded samples after a preincubation with PLA(2), which also increased the labeling of the intracellular membranes. The localization of phospholipids in the areas of initial mineralization suggests some hypotheses on the possible involvement of these molecules in the mineral phase deposition process.

Animals↗

PubMed1996

Matrix vesicles and focal proteoglycan aggregates are the nucleation sites revealed by the lanthanum incubation method: a correlated study on the hypertrophic zone of the rat epiphyseal cartilage.

Correlated studies were performed with light and electron microscopy, and backscattered electron image in conjunction with X-ray microanalysis, of lanthanum-incubated epiphyseal cartilage of the young rat. The hall-mark of this procedure is the appearance of LaP electron-dense deposits (not present in control sections) in precise sites of the hypertrophic zone. The ultrastructural study revealed a dual nature of these sites: "dense matrix vesicles" and "focal filament aggregates". The dense matrix vesicles are a specific type of matrix vesicle with the intrinsic capacity of precipitating LaP mineral, as soon as they originate from the hypertrophic chondrocytes. Furthermore, the matrix vesicles were found to be heterogeneous because lanthanum-devoid, "light matrix vesicles" were also present. The focal filament aggregates, which were not recognized in unstained sections and in controls, are apparently focal concentrations of proteoglycans with high lanthanum binding capacity, although the presence in them of other components (e.g., type X collagen, C-propeptide of type II collagen) cannot be excluded. The were in close connection with the light matrix vesicles in the upper hypertrophic zone, and were loaded with a variable quantity of LaP irregular electron-dense deposits in the lower hypertrophic zone. These irregular deposits are similar to, but distinct from, calcification nodules. The lanthanum incubation method indirectly detects the matrix Ca-binding components (which bind La ions), and the calcification initiation sites (which precipitate a LaP-mineral phase). A sequence is proposed of successive steps of LaP nucleation within the focal filament aggregates, which possibly mimics calcium phosphate deposition. Such a sequence seems to require the participation not only of dense matrix vesicles, but also of the filamentous components of the focal aggregates, possibly together with the activity of alkaline phosphatase.

Animals↗

PubMed1996

Combined use of malachite green fixation and PLA2-gold complex technique to localize phospholipids in areas of early calcification of rat epiphyseal cartilage and bone.

Two cytochemical methods (malachite green fixation and PLA2-gold complex technique) were combined in order to detect the presence and ultrastructural distribution of phospholipids in epiphyseal cartilage and metaphyseal bone of 25-day-old rats. Chondrocytes and osteoblasts showed a more intense PLA2-gold complex labeling of rough endoplasmic reticulum than mitochondria and plasma membranes. Roundish osmiophilic, electron-dense, lightly labeled structures were visible at the periphery of the cells. In areas of early mineralization of cartilage, not all the matrix vesicles were labeled by PLA2-gold complex. Calcification nodules showed intense labeling in comparison with the surrounding, lightly labeled uncalcified matrix; gold particles were chiefly found at their periphery. Calcification nodules of metaphyseal bone were deeply electron-dense after glutaraldehyde-malachite green fixation; PLA2-gold labeling was mainly found in connection with crystals, whereas the uncalcified matrix was weakly labeled. Calcified bone matrix showed a heavy labeling with randomly scattered gold particles. When pre-embedding decalcification was carried out in the presence of malachite green, a good preservation of organic component was obtained. The PLA2-gold positivity of decalcified areas of cartilage and bone confirmed the presence of phospholipids in mineralized matrix.

Animals↗

PubMed1996

Frequency of adynamic bone disease and aluminum storage in Italian uraemic patients--retrospective analysis of 1429 iliac crest biopsies.

BACKGROUND: Adynamic bone disease was initially attributed too aluminum intoxication in association with low circulating levels of parathyroid hormone. More recently adynamic bone disease has been described even in the absence of aluminum intoxication. PURPOSE OF THE STUDY: It was the purpose of this retrospective analysis of 1429 iliac crest biopsies sent to our laboratory from 1985 to 1994 by 41 Italian nephrology and dialysis centres to assess the frequency of adynamic bone disease and aluminum accumulation. METHODS: Adynamic bone disease was diagnosed by histological and histodynamic (tetracycline labelling) analysis, on the basis of predetermined criteria. Aluminum accumulation was assessed by aluminon histochemical staining. RESULTS: The frequency of adynamic bone disease was fairly constant at approximately 15% from 1985 to 1994. In contrast, aluminum accumulation, defined as positive aluminon histochemical staining, decreased during the same period from 36% to 4%. CONCLUSIONS: Our data clearly show a dissociation of the incidence of adynamic bone disease and aluminium accumulation in bone. At least today, given the low prevalence of aluminium intoxication, factors other than aluminium are the main cause of adynamic bone disease.

Aluminum↗

PubMed1996

Renal bone disease in 76 patients with varying degrees of predialysis chronic renal failure: a cross-sectional study.

BACKGROUND: Renal osteodystrophy has been studied less extensively in predialysis than in dialysis patients. Different types or histological patterns in their natural evolution from moderate to advanced severity of renal insufficiency are only partially known, with special regard to adynamic bone disease and its relationship with osteomalacia. METHODS: We conducted a cross-sectional retrospective study on 76 unselected patients with chronic renal failure undergoing conservative treatment, with a wide range of severity of renal insufficiency. All the patients were subjected to bone biopsy for histological and histomorphometric evaluation. The patients, 44 males and 32 females ranging in age from 18 to 72 years and with serum creatinine 1.2-11.4 mg/dl, had not been exposed to aluminium-containing drugs and had never been treated with vitamin D or calcitriol. RESULTS: Ten patients had normal bone, nine were diagnosed with adynamic bone disease, 26 with mild mixed osteodystrophy, seven with predominant osteomalacia, 22 with advance mixed osteodystrophy, and two with predominant hyperparathyroidism. Patients with adynamic bone disease had less severe chronic renal failure than the other pathological subgroups, intact PTH above the upper limit of normal, normocalcaemia, and reduced serum osteocalcin in line with a significantly lower ObS/BS. Osteomalacia was found in a more advanced stage of chronic renal failure with relative hypocalcaemia and more severe metabolic acidosis. A creatinine clearance of 20 ml/min served as a clear demarcation between this histological group and adynamic bone disease. CONCLUSIONS: It is postulated that adynamic bone disease is a form of renal osteodystrophy, separate from osteomalacia, appearing when bone resistance to PTH develops, probably a transient stage to more hyperparathyroid histological classes with increasing severity of chronic renal failure.

Adolescent↗

PubMed1996

Ultrastructure of the organic matrix of embryonic avian bone after en bloc reaction with various electron-dense 'stains'.

The morphological distribution of noncollagenous proteins in bone matrix is poorly known, chiefly because their amount changes with the type of bone, and they are not easily recognizable under the electron microscope. The aim of this study was to obtain further ultrastructural data on these proteins and on their relationships with collagen fibrils and the calcification process. Specimens of woven bone from the upper metaphysis of the tibia of chick embryos were examined after en bloc treatment with acetone solution of KMnO4, or aqueous or alcoholic solutions of phosphotungstic acid or uranyl acetate. Untreated specimens were used as controls. Untreated, decalcified, and decalcified and stained sections were examined. As expected, the results showed that the woven bone matrix of the chick embryo consists of irregularly oriented collagen fibrils which outline wide interfibrillary spaces. These contain calcification nodules at the calcification front and are full of irregularly oriented crystals in completely calcified matrix. These spaces contain greater than expected amounts of filamentous or granular organic structures (probably corresponding to noncollagenous proteins), which are in a close relationship with needle- and filament-like crystals. The collagen fibrils are calcified to a lower degree than the interfibrillary spaces, and often appear uncalcified, or decalcified, when the interfibrillary spaces do not. This suggests that either the former calcify after the latter, or the respective mineral phases differ in their degree of solubility, so that the decalcification of collagen fibrils precedes that of interfibrillary spaces. The results confirm that woven bone contains an amount of interfibrillar noncollagenous material greater than lamellar bone, and show that woven bone calcification occurs not only in and on collagen fibrils, but chiefly between them, in relationship with noncollagenous filamentous material.

Animals↗

PubMed1995

The anatomy of bone sialoprotein immunoreactive sites in bone as revealed by combined ultrastructural histochemistry and immunohistochemistry.

Bone sialoprotein was immunolocalized at the EM level in thin Lowicryl K4M sections of rat bone. Because of the unconventional EM morphology of the bone matrix seen in thin demineralized acrylate sections, the pattern of immunolabeling was compared with detailed structural images of demineralized bone obtained using an en bloc treatment of tissue samples with the cationic electron 'dye,' Malachite Green (MG), which provides stabilization and retention of anionic material throughout specimen processing. A system of structures corresponding to the sites of bone sialoprotein (BSP) immunoreactivity, as seen in Lowicryl K4M this sections, could be readily identified in the MG-treated, epoxy thing sections. This system includes the cement lines, and aggregates of similar material within mineralized bone and mineralizing osteoid. The virtual identity of BSP distribution with the arrangement of the MG-visualized material indicates that a BSP-enriched, noncollagenous phase can be demonstrated using different, unrelated tissue preparation and imaging protocols for EM. Besides improving our understanding of the distribution of bone sialoprotein in bone, these data assign a previously unrecognized structural dimension to noncollagenous material in the bone matrix.

Animals↗

PubMed1995

Prevention of ovariectomy osteopenia in rats after vaginal administration of Hyaff 11 microspheres containing salmon calcitonin.

The benzyl ester of hyaluronic acid (Hyaff 11) is a highly mucoadhesive polymer and can be processed into microspheres that can effectively deliver incorporated drugs by closely adhering to the mucosal surface and by protecting the drug from enzymatic inactivation. In this study, Hyaff 11 microspheres have been investigated as novel delivery system for the vaginal administration of salmon calcitonin (sCT) to ovariectomized rats. Moreover, this particular animal model has been used to evaluate the biological activity of the polypeptide after vaginal and I.M. administration by measuring the skeletal effect of sCT. A total of 66 female rats were used: 6 rats served as the basal group; 12 were subjected to sham operation and left without pharmacological treatment; 48 underwent bilateral ovariectomy and these were divided at random into four groups of 12 animals. One group was not submitted to pharmacological treatment; another was treated daily with sCT I.M.; in the other two groups, the hormone was incorporated into Hyaff 11 microspheres and was daily administered by vaginal route as dry powder or dispersed in pessaries. Sixty days after surgery, rats were sacrificed and the proximal third of the right tibia was removed and prepared for histomorphometry. Treatment with sCT, independent of the administration route, largely prevented the bone volume loss of the nontreated ovariectomized group. Prevention mainly depended on the maintenance of the trabecular number and on the increase of the trabecular thickness. Independent of the administration procedure, sCT greatly reduced the increase of tartrate-resistant acid phosphatase-positive poly- and, particularly, mononucleated osteoclasts found in the nontreated ovariectomized group.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Intravaginal↗

PubMed1995

Extent of alkaline phosphatase cytochemistry vs. extent of tetracycline fluorescence in the evaluation of histodynamic variables of bone formation.

Alkaline phosphatase (ALP) activity is a new histomorphometric index of the extent of osteoblastic surfaces involved in mineralization. To assess its validity in the evaluation of bone formation, we carried out a comparative study between histomorphometric values obtained on the basis of the extent of tetracycline labeling and of the length of ALP-positive endosteal surfaces. The following variables were compared (indicated by ALP when based on the extent of ALP positivity): trabecular mineralizing surface (MS/BS vs. ALP.S/BS); osteoid mineralizing surface (MS/OS vs. ALP.S/OS); bone formation rate (BFR/BS vs. ALP.BFR/BS); and adjusted appositional rate (Aj.AR vs. ALP.Aj.AR). Bone biopsies from 39 patients with chronic renal failure and different types of renal osteodystrophy were considered (48 +/- 12 years of age; 19 men and 20 women). Patients were double labeled with tetracycline and biopsies were embedded in glycol-methacrylate at +4 degrees C. Patients showed various types of renal osteodystrophy and were assigned to different groups of pathologies. Although it differed in incidence according to the different groups, ALP activity was found in typical plump osteoblasts bordering osteoid seams and in flat cells, either in contact with osteoid or along the quiescent surfaces of bone in continuity with it. Tetracycline codistributed with all these features to variable extents, according to groups. In all patients, however, ALP.S/BS and ALP.S/OS respectively exceeded MS/BS and MS/OS. In consequence of this, ALP.BFR/BS and ALP.Aj.AR were greater than BFR/BS and Aj.AR, respectively. For each of the variable considered, differences among groups of patients with different types of renal osteodystrophy were highly significant. Good correlations were found between the variables measured with the two methods.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1995

Ultrastructural organic-inorganic relationships in calcified tissues: cartilage and bone vs. enamel.

Close organic-inorganic relationships exist in all calcified tissues, the inorganic substance being linked to crystal ghosts (CGs). These are organic, crystal-like structures present in areas of initial calcification. In cartilage and bone, they form aggregates with the same morphology and distribution as the calcification nodules; in enamel, they consist of long filament- and ribbon-like structures, having the same arrangement as untreated crystals. CGs of cartilage and bone are acidic structures with histochemical properties of proteoglycans; CGs of enamel probably correspond to enamelins. The close morphologic similarity between CGs and crystals suggests that the former have a role in the formation of the latter.

Bone and Bones↗

PubMed1995

Lectin binding properties of bovine resting cartilage.

The aim of this study was to evaluate the differential localisation of glycoconjugates of bovine hyaline cartilage matrix by lectin histochemistry, to compare the results of lectin histochemistry with those that can be obtained in the same tissue with PAS and alcian blue. Frozen and paraffin sections were stained with HE, PAS and alcian blue (pH 1.8). Alcian blue staining was carried out also after 1 and 24 hour digestion with bovine testicular hyaluronidase. Peroxidase conjugated WGA, PNA and RS lectins were tested on all sections before and after 1 hour digestion with bovine testicular hyaluronidase. The results show that all the lectins used in this study react with sugars linked to proteoglycans of territorial matrix, the reaction being increased in territorial, and induced in interterritorial matrix by 1 hour hyaluronidase digestion. Alcian blue at pH 1.8 and PAS were complementary, the former staining territorial, and the latter interterritorial matrix. After 1 hour hyaluronidase digestion, alcian blue stained also the interterritorial matrix. These results suggest that lectins react with low molecular weight proteoglycans and that short hyaluronidase digestion causes depolymerization of high molecular weight proteoglycans without loss of their glucidic components, allowing: a) penetration of alcian blue molecules into the macromolecular proteoglycan network; b) an increase of sugar residuals available for lectin histochemistry. Lectin histochemistry can be useful for differential localisation of glycoconjugates in bovine cartilage, especially if associated with short hyaluronidase digestion and conventional histochemical techniques.

Alcian Blue↗

PubMed1995

Diagnostic value of serum peptides of collagen synthesis and degradation in dialysis renal osteodystrophy.

The assay of serum peptides of bone collagen formation and degradation could potentially provide an indirect estimate of the rate of bone turnover. In our study we have measured serum levels of the carboxy-terminal propeptide of type I procollagen (PICP) as a marker of bone formation and serum levels of the pyridinoline cross-linked telopeptide domain of type I collagen (ICTP) as a marker of bone resorption in 53 patients (47.7 +/- 10 years, M +/- SD) on haemodialysis (for 9.5 +/- 3.8 years) and affected by renal osteodystrophy. Besides PICP and ICTP, patients were also sampled for serum intact and C-terminal PTH, osteocalcin (BGP) and alkaline phosphatase (AP). A transiliac bone biopsy for histomorphometry was also performed in all. As expected both PTH assays, BGP and AP, were correlated reciprocally and to histomorphometric parameters. As for serum levels of PICP, they were on average increased (268.5 +/- 104.9 ng/ml, M +/- SD) compared to normals (range 66-176), but not correlated to classical humoral markers of hyperparathyroidism (PTH and AP), with the exception of BGP (with a rather low r value: 0.365, P < 0.01), nor to histomorphometric indices of bone resorption and formation.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaline Phosphatase↗

PubMed1995

Clinical features of 24 patients on regular hemodialysis treatment (RDT) for 16-23 years in a single unit.

Careful investigation of the clinical conditions of patients on maintenance hemodialysis for about 20 years in a single dialysis unit was of great interest for evaluation of the pathological consequences in long-term survivors of insufficient correction of uremia and of the dialysis treatment "per se". We analyzed the outcomes for a cohort of 116 patients who started RDT before 1976 and the clinical conditions of the 24 patients still on RDT in our unit at the end of 1991 (average duration of treatment = 222 +/- 23 months). Actuarial survival was 72% at 10 years and 43% at 20 years. Rehabilitation of the 24 survivors was rather good: 13 were able to work, 8 were retired or unable to work, but able to care for most personal needs. Actual body weight, anthropometric parameters and biochemical parameters revealed a well-preserved nutritional status. Anemia improved from 23 +/- 7 at the start of RDT to 31 +/- 8 in the 21 patients never treated with erythropoietin. Blood pressure was normal without therapy in 18 patients and elevated in 6. Mild-to-moderate left ventricular hypertrophy was present in all the 6 patients with arterial hypertension and in only 6 of the 18 normotensive patients. The ratio of early diastolic filling to filling during atrial contraction (E/A ratio) was < 1 in 16 patients: it was 1.05 +/- 0.43 in 9 patients with stable intradialysis blood pressure and significantly lower (0.73 +/- 0.15) in 12 patients with recurrent intradialysis hypotension. Supraventricular arrhythmias were detected by Holter monitoring in 41% and ventricular arrhythmias in 35% of patients. Extensive vascular calcifications were present (in 100% of patients in the abdominal aorta), but only 4 patients showed clinical signs of peripheral vascular disease. Subperiosteal resorption was detected radiologically in the hands of 59% of patients. Bone histology, interpretable for only 20 patients, revealed no bone lesions in 1 case (5%), mild mixed osteodystrophy in 3 cases (15%), advanced mixed osteodystrophy in 5 cases (25%), osteodystrophy with predominant hyperparathyroidism in 2 cases (10%), osteodystrophy with predominant osteomalacia in 6 cases (30%), and aplastic bone disease in 3 cases (15%). Moderate aluminum staining was found in only 4 patients and was more marked in earlier biopsies taken before withdrawal of the aluminium-containing phosphate-binding drugs.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗