Biomedical subjects

S Giannini

Publications and source records attributed to S Giannini.

At least 19 recordsLinked to original sources

PubMed2006

Rear-foot, mid-foot and fore-foot motion during the stance phase of gait.

This paper proposes a new protocol designed to track a large number of foot segments during the stance phase of gait with the smallest possible number of markers, with particular clinical focus on coronal plane alignment of the rear-foot, transverse and sagittal plane alignment of the metatarsal bones, and changes at the medial longitudinal arch. The shank, calcaneus, mid-foot and metatarsus were assumed to be 3D rigid bodies. The longitudinal axis of the first, second and fifth metatarsal bones and the proximal phalanx of the hallux were also tracked independently. Skin markers were mounted on bony prominences or joint lines, avoiding the course of main tendons. Trajectories of the 14 markers were collected by an eight-camera motion capture system at 100 Hz on a population of 10 young volunteers. Three-dimensional joint rotations and planar angles were calculated according to anatomically based reference frames. The marker set was well visible throughout the stance phase of gait, even in a camera configuration typical of gait analysis of the full body. The time-histories of the joint rotations and planar angles were well repeatable among subjects and consistent with clinical and biomechanical knowledge. Several dynamic measurements were originally taken, such as elevation/drop of the medial longitudinal arch and of three metatarsal bones, rear-foot to fore-foot rotation and transverse plane deformation of the metatarsus. The information obtained from this protocol, consistent with previous clinical knowledge, enhanced our understanding of the dynamics of the human foot during stance.

Adult↗

PubMed2006

Determinants of adherence to osteoporosis treatment in clinical practice.

INTRODUCTION: Poor adherence to prescribed treatments is widespread in clinical practice and this can lead to potentially life-threatening events. This problem is apparently very common for osteoporosis treatment but the causes of discontinuation and low compliance are complex and poorly defined. METHODS: Global adherence to osteoporosis treatment was specifically addressed in a nation-wide survey carried out in 9851 postmenopausal women referred to 141 Italian centres for osteoporosis management for a follow-up assessment, at least one year after having been prescribed a treatment with one of the following drugs: calcium+/-vitamin D supplements alone (CaVitD), hormone replacement therapy (HRT), raloxifene 60 mg (RLX), intramuscular clodronate 100 mg/7-14 days (CLOD), risedronate 5 mg/day (RIS) and alendronate 10mg/daily (ALN10) or 70 mg once weekly (ALN OW). RESULTS: Overall 19.1% of the patients discontinued the prescribed drug before attending the bone mass re-evaluations, more than half of them within the first 6 months. The discontinuation rate was significantly different between the treatments. The medications most frequently interrupted within one year were CLOD (28.7%; p<0.01 versus any other treatment), while by far the least interrupted was ALN-OW (6.9%; p<0.001 versus any other treatment). The most frequent reasons for discontinuation were drug related side effects, insufficient motivation to treatment and fear of side effects. The prevalence of the reasons for discontinuation were different among treatments: safety concerns were very common for HRT, lack of motivation was the most common cause for CaVitD and CLOD, and drug related side effects for RIS, ALN and RLX. Persistence to treatment was significantly higher in patients with previous vertebral fractures, densitometric osteoporosis, on corticosteroid or anti-inflammatory treatments. A significantly increased risk of treatment interruption was found among patients on benzodiazepine or gastro-protective agents and in patients in whom a bone measurement was not readily available. The highest compliance to recommended dosing was observed with ALN OW and HRT (p<0.001 versus any other) and the lowest for CaVitD (p<0.01 versus any other). Poor treatment compliance (<50% drug taken) was significantly related to benzodiazepine and gastroprotective use, while a significantly better compliance was associated with recognized risk factors for osteoporosis: early menopause, low bone mass values values, previous vertebral fractures. The poorest adherence was observed when treatments were prescribed by General practitioners (GPs), and orthopaedic surgeons (p<0.01 versus global mean). CONCLUSIONS: The results of this large survey of Italian osteoporotic women indicates that the most important determinant of both persistence and compliance to treatment is the type of drug prescribed with a definite advantage of ALN-OW. Treatment compliance is particularly poor for CaVitD and this emphasizes the need for new ways to supplement at least vitamin D. The main reasons for discontinuation are side effects and lack of motivation while the best treatment adherence was observed in patients with severe and well documented osteoporosis.

Aged↗

PubMed2006

Influence of tibial component posterior slope on in vivo knee kinematics in fixed-bearing total knee arthroplasty.

The relation between prosthesis component kinematics and posterior slope of the tibial component in total knee arthroplasty is much debated. Three-dimensional kinematics of the replaced knee was obtained by video fluoroscopy in 23 knees treated by cruciate-retaining or cruciate-substituting arthroplasty. Relative position and orientation of the metal components were calculated in stair ascending, getting up from and sitting down on a chair, and single step up-and-down. Significant correlations were found between tibial component posterior slope and anteroposterior position of tibiofemoral lateral contact and between this slope and maximum knee flexion. These correlations were task and design specific. However, the average of the tibiofemoral contact positions over all three motor tasks was slightly posterior to the midline of the tibial base plate, reaching at most 84% of its anteroposterior dimension. Performing a posterior slope of the tibial cut does not put total knee arthroplasty with high conforming designs at higher risk of failure, even when large posterior inclinations need to be achieved.

Aged↗

PubMed2006

Effect of short-term therapy with recombinant human growth hormone (GH) on metabolic parameters and preclinical atherosclerotic markers in hypopituitary patients with growth hormone deficiency.

OBJECTIVE: This study examines the effects of growth hormone replacement on body composition, insulin sensitivity, lipid profile, endothelial dysfunction and carotid intima media thickness in patients with adult-onset growth-hormone (GH) deficiency. METHODS: Twelve patients with severe GH deficiency received GH replacement for one year. In all patients, the following parameters were evaluated before and after six and twelve months of therapy: fasting glucose, insulin levels and lipid profile, bone mineral density and body composition. Carotid intima media thickness and brachial flow-mediated dilatation were also evaluated by arterial ultrasonography at basal condition and after one year of therapy. RESULTS: No significant changes were seen in body weight and blood pressure, total fat and lean mass, or bone mineral density after six months of GH replacement. There was an increase in triglycerides (p = 0.05), while total and HDL cholesterol, blood glucose, insulin levels did not change significantly. After twelve months, an increase in lean mass and a decrease in fat mass (p < 0.01 vs. baseline), a decrease in insulin resistance (p < 0.01 vs. six months; p = 0.01 vs. baseline) and a decrease in triglycerides (p < 0.01) were observed. Intima media thickness was greater in GH deficiency than in controls (p = 0.01) before therapy, and was unchanged after twelve months of therapy, whereas the flow-mediated dilatation tended to improve (p = 0.05). CONCLUSIONS: GH replacement is able to reverse typical metabolic and body composition alterations in patients with adult GH deficiency after twelve months, but it is unable to revert the vascular alteration completely. Flow-mediated dilatation seems to be a more precocious marker of the remission of arterial damage.

Adult↗

PubMed2006

Current augmentation fixation techniques for the osteoporotic patient.

Osteoporosis is defined as the deterioration of microarchitecture and overall poor bone quality, which represents a risk of implant fixation failure when patients with osteoporosis are surgically treated. Fragility fractures in elderly patients, typically at the hip, spine and wrist, should be assessed by the orthopaedic surgeon prior to surgery in order to select the most appropriate technique necessary to overcome failures and other complications associated with reduced osteofixation. In this review, advanced methods of augmenting implant fixation in osteoporotic bone are described including polymethylmethacrylate (PMMA), bone grafts, calcium phosphate implants, calcium phosphate cements, calcium phosphate coatings, modified implants and pharmaceutical augmentation concepts. The indication for these techniques should be based on the quantitative assessment of the osteoporotic quality of bone evaluated by dual energy X-ray absorptiometry (DXA).

Bone Cements↗

PubMed2006

Anemia in inflammatory bowel disease.

Anemia is a frequent extraenteric complication of inflammatory bowel disease (IBD, Crohn's disease and ulcerative colitis). A systematic review of the literature shows that the overall prevalence of anemia ranges from 8.8% to 73.7% but differs whether in a setting of Crohn's disease or ulcerative colitis. A disabling complication of IBD, anemia worsens the patient's general condition and quality of life, and increases hospitalization rates. Different factors, including vitamin B12 and folic acid deficiency, bone marrow suppression secondary to drug therapy, autoimmune hemolytic anemia and the coexistence of myelodysplastic syndromes are involved in the pathogenesis of anemia in IBD. The main types of anemia in IBD are iron deficiency anemia and anemia accompanying chronic diseases. Correct diagnostic definition of anemia is a fundamental step in guiding the choice of therapeutic options, since the co-presence of different pathogenetic factors may sometimes require a more complex treatment plan. A review of anemia in IBD, its pathogenetic features, epidemiology, diagnosis and therapy based on evidence from recent studies is the focus of this article.

Anemia↗

PubMed2005

Bone microarchitecture evaluated by histomorphometry.

The increasing use of densitometric devices for assessing bone fragility has progressively strengthened the assumption that mass is the most important property determining bone mechanical competence. Nevertheless, structure and microarchitecture are relevant aspects of bone strength. The study of microarchitecture is based on the measure of width, number, and separation of trabeculae as well as on their spatial organization. There are several methods to assess bone architecture, particularly at the trabecular level. In particular, histomorphometry, based on the use of optical microscopy and on the principles of quantitative histology and stereology, evaluates microarchitecture two-dimensionally, even if these measures appear well correlated to the three-dimensional structure and properties of bone. In addition, new computerized methods allow the acquisition of more sophisticated measurements by means of a digitizer have been introduced to integrate the use of the microscope. These methods supply information on trabecular width as well as on its distribution and on the organization of the trabeculae in the marrow space. Microarchitecture seems to be a determinant of bone fragility independent of bone density and it is important for understanding the mechanisms of bone fragility as well as the action of the drugs used to prevent osteoporotic fractures. Several in vivo studies (on animals and humans) can provide an additional interpretation for the anti-fracture effect of such drugs. For instance, bisphosphonates and parathyroid hormone seem to preserve or even improve microarchitecture. The challenge for the future will be to evaluate bone quality in vivo with the same or better resolution and accuracy than the invasive methods used today.

Animals↗

PubMed2005

Quantitative heel ultrasound in a population-based study in Italy and its relationship with fracture history: the ESOPO study.

We assessed the clinical usefulness of quantitative ultrasound (QUS) in defining the prevalence rates of osteoporosis and osteopenia and their association with fractures of the forearm, vertebrae, and hip. The ESOPO study was conducted in 2001 and assessed a random sample of 11,011 women and 4,981 men, in 83 centers spread all over Italy. A large array of risk factors was investigated, and self-reported history of fractures was collected in a questionnaire. After the patient had undergone interview and a brief physical examination, QUS of the heel was performed, using the Achilles apparatus (GE-Lunar, Madison, USA). The prevalence rate of osteoporosis in women 40-79 years old was approximately 18.5%, while the rate of osteopenia was about 44.7%; in men 60-79 years of age the rates were 10% and 36%, respectively. A strong association with fractures was found for osteoporosis and osteopenia in both men and women, independently of all traditional risk factors, including age. These results confirm the suitability of US measurements as a tool for detecting individuals at risk of fractures.

Adult↗

PubMed2005

Histomorphometric analysis of glucocorticoid-induced osteoporosis.

Bone histomorphometry or quantitative histology consists of counting or measuring tissue components: cells, extracellular constituents and microarchitecture. Bone histomorphometry is the only method that allows the measurement of mineralization rate and the study of bone formation at three levels: cell, remodeling unit and tissue levels. It is a useful tool to explain the pathogenesis and cellular mechanisms of different metabolic bone diseases such as glucocorticoid-induced osteoporosis (GIO). Glucocorticoids (GC) affect calcium and bone metabolism at every level, but the main effect is the osteoblastic dysfunction. Concerning the bone formation, some histomorphometric studies have shown a depressed osteoblastic activity at a cell, bone remodeling unit, and tissue levels. In addition, there is evidence of a shortening of the period in which the osteoblasts work actively forming the bone matrix. This latter effect seems to occur after high cumulative doses of GC. With regard to the resorption, the results are still debated, but histomorphometric parameters seem to be increased in the majority of studies, at least in the first period of the GC treatment. From a structural point of view, GC seem to induce a thinning of the trabeculae without their perforation, which occurs only after high cumulative doses. Anti-resorptive treatments, such as bisphosphonates, are able to counteract the negative effects of GC on bone. In particular, along with their active working period, they prolong the lifespan of osteoblasts and osteocytes. In addition, the anti-resorptive treatments seem to extend the time for secondary mineralization through a reduction of the Activation Frequency. The latter is an intriguing mechanism of bisphosphonates in GIO that needs further ad hoc investigations.

Animals↗

PubMed2005

Association of quantitative heel ultrasound with history of osteoporotic fractures in elderly men: the ESOPO study.

In order to evaluate the usefulness of calcaneal quantitative ultrasound (QUS) in the assessment of male osteoporosis, a cross-sectional, population-based study was performed. A cohort of 4,832 men, randomly selected, community-dwelling, aged 60-80 years and representative of the general older male Italian population was recruited. QUS measurements were assessed in 83 centers distributed all over Italy and equipped with an Achilles device (GE-Lunar, Madison, Wisconsin, USA). All participants were administered a questionnaire covering lifestyle variables and medical history. Low-energy fractures that had occurred since age 50 were recorded. Overall, 43 subjects reported a previous hip fracture and 455 subjects reported other non-spinal fractures. Univariate analysis showed that fractured subjects were older, with a lower level of outdoor physical activity and a more frequent history of prolonged bedridden periods in comparison with unfractured subjects. Men reporting non-spinal fractures showed a higher prevalence of smoking, while no difference was found among groups in anthropometric measures and calcium intake. QUS measurements showed that all QUS parameters were significantly lower in both fracture groups (p<0.001). Multiple logistic regression analysis demonstrated that each SD reduction in QUS measures was associated with an approximate doubling of the risk for hip fracture, independent of age and other clinical variables (broadband ultrasound attenuation [BUA]: odds ratio [OR]=2.24; 95% confidence interval [CI] 1.61-3.08; stiffness index: OR=2.19; CI 1.56-3.11; speed of sound [SOS]: OR=1.71; CI 1.18-3.24) and with an increase of the risk of other non-spinal fractures (BUA: 1.38; CI 1.22-1.59; stiffness index: OR=1.27; CI 1.17-1.38; SOS: OR=1.14; CI 0.96-1.40). It can be concluded that calcaneal QUS measurement is associated with the risk for hip fracture and any non-spinal fractures among a community-dwelling cohort of elderly men. The strength of the association between QUS measurement and fracture is similar to that observed in elderly women.

Aged↗

PubMed2005

The detached osteochondral fragment as a source of cells for autologous chondrocyte implantation (ACI) in the ankle joint.

OBJECTIVE: Autologous chondrocyte implantation (ACI) has been successfully used for the treatment of osteochondral lesions of the talus. One of the main problems of this surgical strategy is related to the harvesting of the cartilage slice from a healthy knee. The aim of this study was to examine the capacity of chondrocytes harvested from a detached osteochondral fragment to proliferate and to serve as a source of viable cells for ACI in the repair of ankle cartilage defects. METHODS: Detached osteochondral fragments harvested from the ankle joint of 20 patients with osteochondral lesions of the talus served as the source of human articular cartilage specimens. All of the osteochondral lesions were chronic and of traumatic origin. In all cases, the fragments were utilized to evaluate the viability and proliferation of the cells, the histological appearance of the cartilage tissue and the expression of specific cartilage markers by real-time polymerase chain reaction (PCR). In the 16 patients scheduled for ACI, the expanded chondrocytes were used for chondrocyte implantation. In the other 4 patients, with lesion size <1.5cm(2), microfractures were created during the initial arthroscopic step. As a control group, 7 patients with comparable osteochondral lesions underwent the same surgery, but received chondrocytes harvested from the ipsilateral knee. RESULTS: According to the American Orthopaedic Foot and Ankle Scoring (AOFAS) system, patients in the experimental group had a preoperative score of 54.2+/-16 points and a postoperative one of 89+/-9.6 points after a minimum follow-up time of 12 months (P<0.0005). The control group of patients had a preoperative score of 54.6+/-11.7 points and a postoperative one of 90.2+/-9.7 points at a minimum follow-up time of 12 months (P<0.0005). The clinical results of the two groups did not differ significantly from each other. Chondrocytes isolated from the detached fragments were highly viable, phenotypically stable, proliferated in culture and redifferentiated when grown within the three-dimensional scaffold used for ACI. The morphological and molecular characteristics of the cartilage samples obtained from the detached osteochondral fragments were similar to those of healthy hyaline articular cartilage. CONCLUSIONS: The good results achieved with this strategy indicate that cells derived from the lesioned area may be useful in the treatment of osteochondral defects of the talus.

Adult↗

PubMed2005

A novel nitric oxide-releasing statin derivative exerts an antiplatelet/antithrombotic activity and inhibits tissue factor expression.

BACKGROUND: NO-releasing statins are new chemical entities, combining HMG-CoA reductase inhibition and slow NO release, that possess stronger anti-inflammatory and antiproliferative activities than the native statins. OBJECTIVE: We evaluated the antithrombotic effects of nitropravastatin (NCX-6550) by assessing its activity on platelet activation and tissue factor (TF) expression by mononuclear cells in vitro and in vivo. METHODS AND RESULTS: In vitro, NCX-6550 inhibited (1) U46619- and collagen-induced platelet aggregation in buffer and plasma; (2) collagen-induced P-selectin expression in whole blood and (3) platelet adhesion to collagen-coated coverslips under high shear stress. These effects were displayed at concentrations of NCX-6550 ranging from 25 to 100 mum, and were totally reverted by the guanylylcyclase inhibitor ODQ (10 microm). Equimolar concentrations of pravastatin had no influence on these parameters of platelet function. LPS- and PMA-induced TF expression by blood mononuclear cells was also inhibited by NCX-6550 (IC50 13 microm), but not by pravastatin, as assessed by functional and immunological assays and by real-time PCR. In a mouse model of platelet pulmonary thromboembolism, induced by the i.v. injection of collagen plus epinephrine, pretreatment with NCX-6550 (24-48 mg kg(-1)) significantly reduced platelet consumption, lung vessel occlusion and mortality. Moreover, nitropravastatin markedly inhibited the generation of procoagulant activity by spleen mononuclear cells and peritoneal macrophages in mice treated with LPS. In these in vivo models too, pravastatin failed to affect platelet activation and monocyte/macrophage procoagulant activity. CONCLUSIONS: Our results show that nitropravastatin exerts strong antithrombotic effects in vitro and in vivo, and may represent an interesting antiatherothrombotic agent for testing in acute coronary syndromes.

Animals↗

PubMed2005

Minimally invasive (99m)Tc-sestamibi radioguided surgery of parathyroid adenomas.

In the last 10 to 15 years surgery of primary hyperparathyroidism (PHPT) moved from the wide bilateral neck exploration to various types of limited neck exploration ranging from unilateral neck surgery to minimally invasive approaches as the minimally invasive radioguided parathyroidectomy. In contrast with the bilateral neck exploration, an accurate preoperative localizing imaging, which is mainly based on (99m)TC-sestamibi scintigraphy, is mandatory when planning a concise parathyroidectomy. Following imaging criteria, only a fraction of PHPT patients accounting for approximately 60% to 70% of all PHPT patients can be eligible for a minimally invasive parathyroidectomy. Only PHPT patients with a high probability to be affected by a solitary parathyroid adenoma showing a high (99m)TC-sestamibi uptake and with a normal thyroid gland should be offer a minimally invasive radioguided parathyroidectomy. The (99m)TC-sestamibi SPECT technique and the double-tracer 123-iodine or (99m)TC-pertecnetate/(99m)TC-sestamibi scintigraphic technique are the most sensitive and accurate preoperative imaging modalities and their utilization is recommended when considering a minimally invasive radioguided parathyroidectomy. Two main intraoperative procedures for the minimally invasive radioguided surgery have been described: the single-day protocol and the different-day protocol. In the single-day protocol a 740 MBq dose of (99m)TC-sestamibi is injected to the patient, scintigraphic imaging is obtained by dual-phase technique and then the patient is operated on within approximately 3 hours from radio-tracer injection. In the different-day protocol, a double-tracer parathyroid scintigraphy is obtained some days before surgery with the aim of better planning the type and extension of intervention. The day of intervention, for the purpose of radioguided surgery only, a low 37 MBq dose of (99m)TC-sestamibi is injected to the patient in the operating theatre a few minutes before the start of intervention. The main advantages of minimally invasive radioguided parathyroidectomy over the traditional wide bilateral neck exploration can be resumed as follows: a shortening in the operating and recovery time, possibility of local anesthesia, possibility of ambulatory surgery or same-day discharge, less postsurgical hypocalcemia, less postsurgical pain, favourable cosmetic results, benefits from a cost-analysis point of view.

Adenoma↗

PubMed2004

Binding and release of cytochrome c in brain mitochondria is influenced by membrane potential and hydrophobic interactions with cardiolipin.

Factors influencing the release and anchorage of cytochrome c to the inner membrane of brain mitochondria have been investigated. Metabolic activity of mitochondria caused a decrease in the membrane potential delta psi(m), accompanied by detachment of the protein from the inner membrane. In a model system of cytochrome c reconstituted in cardiolipin (CL) liposomes, phosphate was used to breach the hydrophilic lipid-protein interactions. About 44% cytochrome c was removable when heart CL (80% 18:2n-6) was employed, whereas the remaining protein accounted for the tightly bound conformation characterized by hydrophobic lipid-protein interactions. Cytochrome c release from brain CL liposomes was higher compared to heart CL, consistent with lower polyunsaturated fatty acid content. The release was even higher with CL extracted from metabolically stressed mitochondria, exhibiting more saturated fatty acid profile compared to control (30% vs. 17%). Therefore, weakening of the hydrophobic interactions due to saturation of CL may account for the observed cytochrome c release from mitochondria following metabolic stress. Moreover, mitochondria enriched with polyunsaturated CL exhibited higher delta psi(m), compared to less unsaturated species, suggesting that CL fatty acid composition influences delta psi(m). Mitochondria incorporated exogenous cytochrome c without protease-sensitive factors or delta psi(m). The internalized protein anchored to the inner membrane without producing swelling, as monitored by forward and side light scattering, but produced delta psi(m) consumption, suggesting recovery of respiratory activity. The delta psi(m) decrease is ascribed to a selected mitochondrial population containing the incorporated cytochrome c.

Animals↗

PubMed2004

Mathematical model for pre-operative planning of linear and closing-wedge metatarsal osteotomies for the correction of hallux valgus.

First-metatarsal osteotomy is performed for an abnormal intermetatarsal angle and severe hallux valgus deformity. The metatarsal head is slid along the osteotomy and fixed with a Kirschner wire to achieve angular and linear realignment with respect to the other metatarsals. When reduction of joint subluxation is also sought, a bone wedge is removed. A mathematical model and a corresponding computer-based tool were developed for pre-operative planning of the optimum surgical solution. Standard intermetatarsal angle correction, head-to-sesamoids re-alignment, joint subluxation reduction and metatarsal length adjustment were all pursued. A standard pre-surgical dorso-plantar radiograph of the patient, with an additional metal ball for calculation of X-ray magnification, was necessary to analyse the original and final geometrical configurations. For the first time, expected bone loss and wire diameter were also considered. The angles of bone cuts and the amount of sliding along these cuts were calculated by the model according to the surgical goal. All the resulting geometrical parameters, both in the pre- and planned post- operative configuration, were provided in graphical and tabular form. In a change from former qualitative analysis of radiograms, the surgeon can now enter the operating theatre with a detailed plan of the goal to be achieved.

Hallux Valgus↗

PubMed2004

Pleiotropic effects of thiazolidinediones: taking a look beyond antidiabetic activity.

Thiazolidinediones (TZD) [Troglitazone (TRO), Pioglitazone (PGZ), Rosiglitazone, (RGZ)] are a novel class of antidiabetic drugs for patients with Type-2 diabetes mellitus (T2DM) able to decrease blood glucose, working through a reduction of insulin resistance. The family of TZD exerts its effect specifically bound to peroxisome proliferator-activated receptor y (PPARy). This is a member of the nuclear hormone receptor superfamily of ligand-dependent transcription factors, together with PPARalpha and deltabeta. Although PPARgamma is essentially expressed in adipose tissue, it has also been found in endothelial cells, macrophages, vascular smooth muscle cells, glomerular mesangial cells, hepatic stellate cells and in several cancer cell lines. In these cells, the PPARgamma activation by TZD determines modulatory effects on growth factor release, production of cytokine, cell proliferation and migration, extracellular matrix remodeling and control on cell cycle progression and differentiation. In addition, TZD have been shown to have a potent antioxidant effect. This review, taking a quick look beyond the antidiabetic activity of PPARgamma, shows the dramatic ranging of medical implications that the use of TZD could have modulating the PPARgamma activity in several diseases with a strong social impact, such as insulin resistance syndrome, chronic inflammation, atherosclerosis and cancer.

Arteriosclerosis↗

PubMed2004

Bone microarchitecture as an important determinant of bone strength.

Structure and microarchitecture are determinant aspects of bone strength and essential elements for the assessment of bone mechanical properties. The main structural determinants of bone mechanical strength include width and porosity in the cortical bone; shape, width, connectivity, and anisotropy in the trabecular bone. There are several methods to assess bone architecture, particularly at the trabecular level. Two different approaches can be identified. The first is based on the use of optical microscopy and on the principles of quantitative histology, which evaluate microarchitecture two-dimensionally. The second applies the most modern diagnostic techniques, employing computed tomography and magnetic resonance to obtain and analyze three-dimensional images. From a clinical point of view, microarchitecture is an interesting aspect to study and define specific patterns, such as glucocorticoid-induced osteoporosis, or to evaluate bone alterations in transplanted patients. Microarchitecture seems to be a determinant of bone fragility independent of bone density. Moreover, bone microarchitecture seems to be important to understand the mechanisms of bone fragility as well as the action of the drugs used to prevent osteoporotic fractures. Several in vivo studies (on animals and humans) showed important findings on the effects of different treatments on microarchitecture. Bisphosphonates and parathyroid hormone seemed to preserve or even improve microarchitecture. These observations can provide an additional interpretation for the anti-fracture effect of drugs from a structural viewpoint. The challenge for the future will be to evaluate bone quality in vivo with the same or better resolution and accuracy than the invasive methods in use today.

Biomechanical Phenomena↗

PubMed2004

Effect of age, weight and lifestyle factors on calcaneal quantitative ultrasound in premenopausal women: the ESOPO study.

The objective of this study was to identify the determinants of bone mass as measured by quantitative ultrasound (QUS) in premenopausal women. The study population is part of the "Epidemiological Study On the Prevalence of Osteoporosis" (ESOPO) on risk of the general population of Italy. We report the data on 2727 premenopausal women aged 40-50 years who are still regularly menstruating. Bone stiffness (called simplicity stiffness), which is derived from the values of broadband ultrasound attenuation (BUA) and speed of sound (SoS), was measured by a heel QUS device (Achilles Apparatus, Lunar, Co. USA). The most commonly recognized determinants of bone mass were modelled with stiffness by multiple regression analysis or analysis of variance (ANOVA). Bone stiffness was negatively related to age and number of cigarettes and positively to body weight, body weight at 25 years, height and estimated daily calcium intake. By multiple regression analysis, independent, positive, predictors of bone stiffness were age, weight at 25 years and daily calcium intake. Bone stiffness adjusted for age and body weight at 25 years was positively associated with outdoor activity score and negatively with number of pregnancies, chronic use of any drug, smoking and subjective health status. Bone stiffness was also somewhat (p < 0.015) negatively related to history of prolonged bedrest and thyroxin use. In conclusion, our results indicate that risk factors usually associated in other studies with DXA-BMD in elderly women are also associated with calcaneal bone stiffness, as measured by QUS in premenopausal women. These findings should help to identify premenopausal women at risk and to design an early strategy for osteoporosis prevention based on eliminating modifiable risks.

Adult↗