L Masi

University of Florence, Florence, Tuscany, Italy

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Publications (42)101.8 Total impact

  • Clin Cases Miner Bone Metab. 01/2011;
  • Clin Cases Miner Bone Metab. 01/2011;
  • Clin Cases Miner Bone Metab. 01/2011;
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    ABSTRACT: Tumoral calcinosis is a rare disease characterized by hyperphosphatemia due to hypophosphaturia and by ectopic calcifications. Phosphatonins are important hormones that regulate phosphorus homeostasis. Tumoral calcinosis is a rare congenital disorder in which the differential diagnosis from other syndromes associated with extraskeletal calcifications may be difficult. Mutations in the UDP-N-acetyl-alpha-D-galactosamine: polypeptide N-acetylgalactosaminyltransferase-3 (GALNT3) and fibroblast growth factor-23 (FGF23) genes have been described. Mutational analysis is important for the early recognition of the disorder, for prevention of its complications, and for family screening strategies. We examined two unrelated white patients affected by tumoral calcinosis. The first patient was a woman with a history of an ectopic calcification in the left shoulder. The second patient was a man with a history of an ectopic calcification in the right buttock. Routine biochemistry and FGF-23 assays were performed on serum samples. Genomic DNA was extracted from peripheral blood. The FGF23 and GALNT3 genes were analyzed by direct sequencing. A new homozygous H41Q codon 41, C-->A transversion at position 123 (c.123C>A) in exon 1 of the FGF23 gene was evidenced in both patients. No mutation of the GALNT3 gene was detected in these patients. As determined by an ELISA assay, intact FGF-23 circulating protein was low in both patients. This is the fourth mutation of the FGF23 gene described in subjects with tumoral calcinosis.
    The Journal of Bone and Joint Surgery 06/2009; 91(5):1190-8. · 3.23 Impact Factor
  • Journal of Clinical Densitometry - J CLIN DENSITOM. 01/2009; 12(1):118-119.
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    ABSTRACT: The increase in life expectancy of cystic fibrosis (CF) patients has brought about a rise in new clinical problems in these patients, such as a decrease in bone mineral density (BMD). The cause of diminished BMD in CF is multi-factorial. The aim of this cross-sectional study, conducted on 39 CF patients under the age of 18 years, was to evaluate the degree of bone mineralization and the prevalence of low BMD in these patients during a follow-up at the Cystic Fibrosis Regional Center of Tuscany, using a dual energy X-ray absorptiometry (DXA) scan, and to then study the factors correlated with low BMD. Areas BMD values (g/cm2) and Z-score values were determined. Eighteen patients (46%) out of the our sample had decreased BMD, while 21 patients (54%) had normal values. A statistically significant association was found between BMD Z-score values and pancreatic insufficiency, BMI<5th percentile and DeltaF508 homozygosis. Subjects treated with oral steroid therapy had a 3.9 times greater risk of developing osteoporosis compared to non-treated subjects (95% C.I.: 1.07-22.6; R.R. 4.9). An association was found between BMD Z-score values and FEV1 values (r=0.29; P=0.06), physical activity total score values (r=0.22; P=0.19) and the Chrispin-Norman chest radiographic score (r=-0.31; P=0.06). Early identification of reduced bone mass values would permit early intervention to prevent the development of osteoporosis. Maintaining pulmonary function, guaranteeing optimal nutritional status, following an adequate program of physical activity and controlling steroid intake could maintain BMD over time.
    Minerva pediatrica 05/2008; 60(2):147-54. · 0.64 Impact Factor
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    ABSTRACT: Bone mineral density (BMD) contributes to bone strength, and methods for clinical assessment of bone quality characteristics beyond what can be gathered by BMD are awaited. Peripheral quantitative computed tomography (pQCT) allows for separate assessments of cortical and trabecular bone, providing information on bone geometry. Previous studies examining the relationship between estrogen receptor alpha (ERalpha) gene polymorphisms and BMD have been performed in large populations. However, only limited information is available on the possible segregation of ERalpha gene polymorphisms with bone structural properties. The aim of our study was to evaluate the association of XbaI and PvuII ERalpha gene polymorphisms with QCT parameters. We studied 900 subjects (541 women, 449 men) participating to the InCHIANTI study. By tibial pQCT we evaluated trabecular volumetric BMD, cortical volumetric BMD, cortical bone area, and cortical thickness (CtTh). Subjects were genotyped for ERalpha gene PvuII and XbaI polymorphisms. Analysis of variance was used for statistical analysis. Male subjects with PP and XX genotypes had higher geometric parameters, and female subjects with XX and PP genotypes showed higher densitometric parameters than other genotypes; however, the differences did not reach statistical significance. After adjustment for potential confounders, we found a significant (P = 0.002) CtTh difference across PvuII polymorphism in male subjects, with higher CtTh values in PP genotypes with respect to Pp and pp genotypes. These results show a relationship between the presence of the P allele and higher values of CtTh in male subjects, indicating for ERalpha a role in the control of tibial bone geometry.
    Calcified Tissue International 06/2007; 80(5):307-15. · 2.75 Impact Factor
  • Clin Cases Miner Bone Metab. 05/2007;
  • Clin Cases Miner Bone Metab. 05/2007;
  • Clin Cases Miner Bone Metab. 05/2007;
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    ABSTRACT: One of the most promising genetic approaches to dissecting a multifactorial disease is represented by genetically isolated population studies. We studied a genetic marker in a cohort of women living on the Mediterranean island of Lampedusa, a geographically isolated population. Lampedusa, located between the African coast and Sicily, consists of a young genetic isolate (<20 generations) with an exponential growth in the last generations. We analyzed the association between the FokI vitamin D receptor (VDR) gene polymorphism, previously proposed as a predictor of bone mass, with parameters of bone mass and turnover in a cohort of pre- and postmenopausal women living on Lampedusa. In 424 women (277 postmenopausal and 147 premenopausal), allelic frequencies were 49% for the F allele and 51% for the f allele. Using analysis of covariance, we found that subjects with ff genotype exhibited a significantly (P < 0.001) lower lumbar spine bone mass, by dual-energy X-ray absorptiometry, and lower values of bone ultrasonographic parameters (speed of sound and broadband ultrasound attenuation) relative to those with Ff and FF genotypes. Conversely, osteocalcin and serum cross-laps were significantly higher in ff and Ff compared to FF genotype. Our data suggest that FokI VDR polymorphism may contribute to the determination of bone mass and turnover in both pre- and postmenopausal women in this geographically isolated population.
    Calcified Tissue International 02/2007; 80(1):15-20. · 2.75 Impact Factor
  • Bone 01/2007; 40(6). · 4.46 Impact Factor
  • Clin Cases Miner Bone Metab. 01/2007;
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    ABSTRACT: The guidelines for the osteoporosis management were first drafted by a working group and then critically evaluated by the board of SIOMMMS. The most relevant points are: Osteoporosis is defined as a quantitative and qualitative deterioration of bone tissue leading to increased risk of fracture. Postmenopausal and senile osteoporosis are defined as primitive. The cornerstone for the diagnosis of osteoporosis is the measurement of bone mineral density (BMD) by DXA (dual-energy X-ray absortiometry) at the femoral neck with T-score values <-2.5, following the WHO definition. Other DXA sites or technologies for measuring bone mass are also acceptable when the former is not accessible. A BMD evaluation is recommended to all women above 65 years of age. At younger age or in man the bone assessment is recommended only in subjects with specific risk factors. A control of bone mass measurement is seldom required before 2 years. A few biochemical tests such as serum and urinary calcium, protein electrophoresis, serum creatinine and ESR are usually sufficient to exclude most secondary types of osteoporosis. The value of the so called bone turnover markers for the diagnosis and follow-up of osteoporosis remains uncertain. Several secondary forms of osteoporosis require a specific diagnostic and therapeutic management. The osteoporosis prevention should be based on the elimination of specific risk factors such as inadequate calcium and vitamin D intake, smoking and sedentary life. The use of pharmacological agents in subjects with BMD values >-2.5 is usually not justified. Pharmacological intervention: The use of drugs registered for the treatment of osteoporosis are recommended when the benefits overcome the risk. This is the case only when the risk of fracture is rather high. FRAX is recognized as a useful tool for easily estimate the long-term fracture risk. SIOMMMS with these guidelines is committed to validate and further develop this diagnostic tool.
    Reumatismo 01/2006; 61(4):260-84.
  • L Masi, M L Brandi
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    ABSTRACT: PTH is a single chain polypeptide with 84 amino acids. The N-terminal region, 1-34, is a biologically active fragment. PTH has both anabolic and catabolic actions on bone. Bauer et al. demonstrated that PTH extract increased trabecular bone in some animals and Selye et al. provided histology evidence that parathyroid extract, when administered in very small doses to rat pups, stimulated osteoblasts and increased bone apposition. The first clinical trial conducted with PTH was performed in 21 patients with osteoporosis treated with human PTH (1-34) [hPTH (1-34)]. In this study, the [hPTH (1-34)] was given as once-daily subcutaneous injections with an increase of 70% above mean baseline values of trabecular bone. Intermittent treatment with PTH increases osteoblast number and bone formation. The skeletal effects of PTH depend upon the pattern of systemic exposure. Once-daily administration of PTH stimulates new bone formation on trabecular and cortical bone surfaces by preferential stimulation of osteoblastic activity over osteoclastic activity. By increasing new bone formation, PTH improves bone mass and bone strength, and thereby reduces the risk of fracture. PTH (1-34) is currently being safely and effectively used in osteoporosis, and together with novel PTH derivates agent provides more tools for the clinicians in their armamentarium for the fight against osteoporosis.
    Journal of endocrinological investigation 02/2005; 28(8 Suppl):37-40. · 1.65 Impact Factor
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    ABSTRACT: Osteoporosis is a skeletal chronic multifactorial disease characterised by abnormal low bone mass and microarchitectural deterioration of bone tissue. This disorder, present in both sexes, related to environmental and genetic factors, is becoming a major public health problem in developed countries. It has a polygenic pattern of inheritance that complicates identification of disease genes [cytokines, calciotropic hormones, sex hormones pathway synthesis and their receptors, bone matrix proteins synthesis genes involved on estrogenic metabolism (CYP19) and LDL receptor-related protein 5 (LRP5) gene]. It is possible to identify associations between candidate genes polymorphisms and disease phenotype in population-based and case-control studies. This could give us promising data for earlier identification of osteoporosis susceptibility and fracture risk. Preventive therapy could be targeted to patients at risk of osteoporosis before fractures occur. Genetic polymorphisms are also starting to be used to predict drug response. A new era of pharmacogenetics represents an interesting prospective to identify the potential individuals to receive customised treatments.
    Journal of endocrinological investigation 02/2005; 28(10 Suppl):2-7. · 1.65 Impact Factor
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    ABSTRACT: Differently from other metabolic conditions, most of calcium metabolism disorders are diagnosed through simple detection of both serum and urinary excretion (24-h urine collection), levels of calcium, total and ionized form, and phosphate, and of calciotropic hormone serum levels, such as calcitonin, PTH and vitamin D metabolites. For the diagnosis and clinical monitoring of some metabolic bone diseases, such as osteoporosis and Paget's disease, the assessment of bone turnover is offering a useful tool for the evaluation of the therapeutic response in affected individuals. Markers of bone formation are represented by bone alkaline phosphatase and osteocalcin, while principal bone resorption markers are represented by pyridinoline, deoxypyridinoline and crosslinks of collagen N-telopeptide, both in the 24-h and fasting second morning urine collection. Only in selected conditions, here briefly reviewed, dynamic tests can offer an interpretation on the pathogenetic events causing a disorder of calcium metabolism.
    Journal of endocrinological investigation 02/2003; 26(7 Suppl):83-91. · 1.65 Impact Factor
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    ABSTRACT: Osteoporosis is a common skeletal disease characterized by low bone mass and microarchitectural deterioration of bone tissue with a consequent increase in bone fragility and susceptibility to fracture. In the past years, twin and family study have shown that this disease recognizes a strong genetic component and that genetic factors play an important role in regulating bone mineral density (BMD). While in few isolate conditions osteoporosis can be inherited in a simple Mendelian pattern, due to single gene mutations, in the majority of cases has to be considered a multifactorial polygenic disease in which genetic determinants are modulated by hormonal, environmental and nutritional factors. Given the important role that steroid hormones play in bone cell development and in the maintenance of normal bone architecture, polymorphisms at receptor of the steroid/thyroid hormone receptor superfamily, such as estrogen receptor alpha (ERalpha) and Vitamin D receptor (VDR) have been thoroughly investigated in the last years and appeared to represent important candidate genes. The individual contribution of these genetic polymorphisms to the pathogenesis of osteoporosis remains to be universally confirmed and an important aim in future work will be to define their functional molecular consequences and how these polymorphisms interact with each other and with the environment to cause the osteoporotic phenotype. A further promising application of genetic studies in osteoporosis comes from their pharmacogenomic implications, with the possibility to give a better guidance for therapeutic agents commonly used to treat this invalidating disorder or to identify target molecules for new therapeutic agents.
    The Journal of Steroid Biochemistry and Molecular Biology 06/2002; 81(1):1-24. · 3.98 Impact Factor
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    ABSTRACT: The authors examined the distribution of tumor growth factor-beta (TGF-beta) isoforms and receptors in 35 giant cell tumor (GCT) of bone in comparison with a group of benign giant cell-containing lesions of bone, including 5 aneurysmal bone cysts, 2 cases of brown tumor of hyperparathyroidism, 3 nonossifying fibromas, and 7 cases of giant cell reparative granuloma. The results of immunohistochemical analysis of GCT showed a complete absence of TGF-beta1 expression in both mononuclear tumor cells and giant cells. Only reactive bone present within the tumor showed an intense immunoreactivity. Transforming growth factor-beta2 and TGF-beta3 were detected in the majority of cases (97.1% and 82.8%, respectively), whereas TGF-beta receptor type I (TGF-beta RI) and type II (TGF-beta RII) were diffusely expressed in all cases. Reverse transcription-polymerase chain reaction (RT-PCR) analysis performed on 10 GCTs with specific oligonucleotide primers demonstrated the presence of mRNA transcripts for TGF-beta1, 2, 3, and for TGF-beta RI and RII. Quantitative measurements of TGF-beta1 in conditioned media from primary cultures of GCT showed undetectable or very low amounts of the cytokine (0-23 pg/mL). The results of immunohistochemical analysis showed that all giant cell-containing lesions of bone were at least focally positive for the 3 isoform of TGF-beta, with positivity present both in osteoclast-like giant cells and mononuclear cells, and diffusely positive for TGF-beta RI and RII. Reverse transcription-polymerase chain reaction analysis conducted on samples from 3 nonossifying fibromas and 1 giant cell reparative granuloma confirmed the expression of the corresponding mRNA. In conclusion, according to the current data, GCT of bone can be distinguished from other giant cell-containing lesions of bone on the basis of the absence of TGF-beta1 expression at the protein level, which appears to be the result of posttranslational regulation processes.
    Applied immunohistochemistry & molecular morphology: AIMM / official publication of the Society for Applied Immunohistochemistry 07/2001; 9(2):170-5. · 1.63 Impact Factor
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    ABSTRACT: Conversion of C(19) steroids to estrogens is catalyzed by the aromatase enzyme. Inactivating mutations of the aromatase gene are associated with decreased bone mineral density in both men and women. Genetic studies suggest that several genes contribute to the regulation of bone mass via interaction with the modeling and remodeling processes. Among these genes, the aromatase gene is a potential candidate to be evaluated for segregation with bone metabolism and bone mass. A tetranucleotide simple tandem repeat polymorphism in intron 4 at the human aromatase cytochrome P-450 gene has been recently described. In the present study we evaluated the distribution of this polymorphism in a cohort of Italian postmenopausal women, both normal and osteoporotic. We observed that the NN genotype was significantly more frequent in nonosteoporotic women than in osteoporotic women (72.7% vs. 27.2%), whereas the DN genotype was significantly more represented in osteoporotic women (90.48% vs. 9.5%; Pearson's chi(2) test = 42.8; df = 10; P = or < 0.01). The allele containing the longer TTTA repeats was statistically more represented in nonosteoporotic women (Pearson's chi(2) test = 19.14; df = 2; P = 0.00007). In addition, women with a high number of TTTA repeats had a significantly higher lumbar bone mineral density than women with alleles containing 8-11 TTTA repeats (P = 0.03). Finally, considering the spine fractures, a significantly higher incidence was observed in women with shorter TTTA repeats than in those with longer TTTA repeats (Pearson's chi(2) test = 7.3; df = 2; P = 0.02), equivalent to a relative risk of 4.1 (95% confidence interval, 1.19-13.87). In conclusion, the aromatase gene can be one of the several genes potentially involved in the maintenance of bone mass and in the regulation of bone mass loss.
    Journal of Clinical Endocrinology &amp Metabolism 05/2001; 86(5):2263-9. · 6.43 Impact Factor

Publication Stats

929 Citations
101.80 Total Impact Points

Institutions

  • 1991–2009
    • University of Florence
      • • Dipartimento di Medicina Sperimentale e Clinica
      • • Dipartimento di Scienze Biomediche, Sperimentali e Cliniche
      Florence, Tuscany, Italy
  • 1995
    • National Institutes of Health
      Maryland, United States
  • 1992
    • Sapienza University of Rome
      Roma, Latium, Italy