PBDEs affect inflammatory and oncosuppressive mechanisms via the EZH2 methyltransferase in airway epithelial cells

AIMS

We aimed to investigate the effect of PBDEs (47, 99, 209) on cellular events involved in epigenetic modification, inflammation, and epithelial mesenchymal transition (EMT).

MATERIALS AND METHODS

We studied: 1) ERK1/2 phosphorylation; 2) Enhancer of Zester Homolog 2 (EZH2); 3) Histone H3 tri-methylated in lysine 27 (H3K27me3); 4) K-RAS; 5) silencing disabled homolog 2-interacting protein gene (DAB2IP), 6) let-7a; 7) Muc5AC/Muc5B, and 8) IL-8 in a 3D in vitro model of epithelium obtained with primary Normal Human Bronchial Epithelial cells (pNHBEs) or A549 cell line, chronically exposed to PBDEs (47, 99, 209).

KEY FINDINGS

PBDEs (10 nM, 100 nM and 1 μM) increased ERK1/2 phosphorylation, and EZH2, H3K27me3, and K-RAS protein expression, while decreased DAB2IP and Let-7a transcripts in pNHBEs ALI culture. Furthermore PBDEs (47, 99) (100 nM) increased Muc5AC and Muc5B mRNA, and PBDE 47 (100 nM) IL-8 mRNA via EZH2 in pNHBEs. Finally, PBDEs (100 nM) affected EZH2, H3K27me3, K-RAS protein expression, and DAB2IP, Let-7a transcripts and cell invasion in A549 cells. Gsk343 (methyltransferase EZH2 inhibitor) (1 mM) and U0126 (inhibitor of MEK1/2) (10 μM) were used to show the specific effect of PBDEs.

SIGNIFICANCE

PBDE inhalation might promote inflammation/cancer via EZH2 methyltransferase activity and H3K27me3, k-RAS and ERk1/2 involvement, generating adverse health outcomes of the human lung.

A 3D "In Vitro" Model to Study Hyaluronan Effect in Nasal Epithelial Cell Line Exposed to Double-Stranded RNA Poly(I:C)

Environmental agents, including viral and bacterial infectious agents, are involved in the alteration of physicochemical and biological parameters in the nasal epithelium. Hyaluronan (HA) has an important role in the regulation of tissue healing properties. High molecular weight HA (HMW-HA) shows greater anti-inflammatory responses than medium molecular weight HA (MMW-HA) and low molecular weight HA (LMW-HA). We investigated the effect of HMW-HA, MMW-HA and LMW-HA on the regulation of physicochemical and biological parameters in an “in vitro” model that might mimic viral infections of the nasal epithelium. Human nasal epithelial cell line RPMI2650 was stimulated with double-stranded RNA (dsRNA) Poly(I:C) for 5 days in air-liquid-interface (ALI) culture (3D model of airway tissue). dsRNA Poly(I:C) treatment significantly decreased transepithelial electrical resistance (TEER) in the stratified nasal epithelium of RPMI2650 and increased pH values, rheological parameters (elastic G’ and viscous G’’), and Muc5AC and Muc5B production in the apical wash of ALI culture of RPMI2650 in comparison to untreated cells. RPMI2650 treated with dsRNA Poly(I:C) in the presence of HMW-HA showed lower pH values, Muc5AC and Muc5B production, and rheological parameters, as well as increased TEER values in ALI culture, compared to cells treated with Poly(I:C) alone or pretreated with LMW-HA and MMW-HA. Our 3D “in vitro” model of epithelium suggests that HMW-HA might be a coadjuvant in the pharmacological treatment of viral infections, allowing for the control of some physicochemical and biological properties affecting the epithelial barrier of the nose during infection.

Cytotoxic and genotoxic effects of the flame retardants (PBDE-47, PBDE-99 and PBDE-209) in human bronchial epithelial cells

Polybrominated diphenyl ethers (PBDEs) are widespread as flame-retardants in different types of consumer products. PBDEs present in the air or dust and their inhalation can damage human health by influencing the respiratory system. We evaluated the effects of environment relevant concentrations (0.01-1  μM) of PBDE-47, PBDE-99 and PBDE-209 on the mechanism of oxidative stress, dysregulation of cell proliferation, apoptosis, and DNA damage and repair (in term of H2AX phosphorylation ser139) in an in-vitro/ex-vivo model of bronchial epithelial cells. PBDEs (-47, -99 and -209) at the environment relevant concentrations (0.01 and 1  μM) induce oxidative stress (in term of NOX-4 expression as well as ROS and JC-1 production), activate the mechanism of DNA-damage and repair affecting Olive Tail length (comet assay) production and H2AX phosphorylation (ser139) in normal human bronchial epithelial cells. Furthermore PBDEs, although do not affect cell viability, induce cell apoptosis and single cell capacity to grow into a colony (like a cancer phenotype) in bronchial epithelial cells. Finally, PBDE-47 had a greater effect than -99 and -209. PBDE-47, -99 and -209 congeners exert cytotoxic and genotoxic effects, and play a critical role in the dysregulation of oxidative stress, damaging DNA and the related gene expression in bronchial epithelial cells. Our findings might suggest that PBDEs inhalation might have adverse effect on human health regarding pulmonary diseases in the areas of environmental pollution.

Can PBDEs affect the pathophysiologic complex of epithelium in lung diseases?

Brominated flame-retardant (BFRs) exposure promotes multiple adverse health outcomes involved in oxidative stress, inflammation, and tissues damage. We investigated BFR effects, known as polybrominated diphenyl ethers (PBDEs) (47, 99 and 209) in an air-liquid-interface (ALI) airway tissue derived from A549 cell line, and compared with ALI culture of primary human bronchial epithelial cells (pHBEC). The cells, exposed to PBDEs (47, 99 and 209) (0.01-1 μM) for 24 h, were studied for IL-8, Muc5AC and Muc5B (mRNAs and proteins) production, as well as NOX-4 (mRNA) expression. Furthermore, we evaluated tight junction (TJ) integrity by Trans-Epithelial Electrical Resistance (TEER) measurements, and zonula occludens-1 (ZO-1) expression in the cells, and pH variations and rheological properties (elastic G', and viscous G″, moduli) in apical washes of ALI cultures. N-acetylcysteine (NAC) (10 mM) effects were tested in our experimental model of A549 cells. PBDEs (47, 99 and 209) exposure decreased TEER, ZO-1 and pH values, and increased IL-8, Muc5AC, Muc5B (mRNAs and proteins), NOX-4 (mRNA), and rheological parameters (G', G″) in ALI cultures of A549 cell line and pHBEC. NAC inhibited PBDE effects in A549 cells. PBDE inhalation might impairs human health of the lungs inducing oxidative stress, inflammatory response, loss of barrier integrity, unchecked mucus production, as well as altered physicochemical and biological properties of the fluids in airway epithelium. The treatment with anti-oxidants restored the negative effects of PBDEs in epithelial cells.

Cigarette smoke affects the onco-suppressor DAB2IP expression in bronchial epithelial cells of COPD patients

Cigarette smoke is a risk factor for COPD and lung cancer. In cancer, epigenetic modifications affect the expression of Enhancer of Zester Homolog 2 (EZH2), and silenced disabled homolog 2 interacting protein gene (DAB2IP) (onco-suppressor gene) by Histone H3 tri-methylation in lysine 27 (H3K27me3). In"ex vivo"studies, we assessed EZH2, H3K27me3 and DAB2IP immunoreactivity in bronchial epithelial cells from COPD patients (smokers, ex-smokers), Smoker and control subjects. In"in vitro" experiments we studied the effect of cigarette smoke extract (CSE) on EZH2/H3K27me3/DAB2IP expression, apoptosis, invasiveness, and vimentin expression in 16HBE, primary cells, and lung cancer cell lines (A549) long-term exposed to CSE. Finally, in "in vitro"studies, we tested the effect of GSK343 (selective inhibitor of EZH2). EZH2 and H3K27me3 expression was higher, while DAB2IP was lower levels, in bronchial epithelium from COPD and Smokers than in Controls. CSE increased EZH2, H3K27me3 expression and decreased DAB2IP, cell apoptosis and invasiveness in epithelial cells. GSK343 restored the effects of CSE. Cigarette smoke affects EZH2 expression, and reduced DAB2IP via H3K27me3 in COPD patients. The molecular mechanisms associated with EZH2 expression, generate a dysregulation of cell apoptosis, mesenchymal transition, and cell invasiveness in bronchial epithelial cells, encouraging the progression of airway inflammation toward lung cancer in COPD patients.

IL-17A-associated IKK-α signaling induced TSLP production in epithelial cells of COPD patients

Thymic stromal lymphopoietin (TSLP) is a cytokine expressed in the epithelium, involved in the pathogenesis of chronic disease. IL-17A regulates airway inflammation, oxidative stress, and reduction of steroid sensitivity in chronic obstructive pulmonary disease (COPD). TSLP and IL-17A were measured in induced sputum supernatants (ISs) from healthy controls (HC), healthy smokers (HS), and COPD patients by enzyme-linked immunosorbent assay. Human bronchial epithelial cell line (16HBE) and normal bronchial epithelial cells were stimulated with rhIL-17A or ISs from COPD patients to evaluate TSLP protein and mRNA expression. The effects of the depletion of IL-17A in ISs, an anticholinergic drug, and the silencing of inhibitor kappa kinase alpha (IKKα) on TSLP production were evaluated in 16HBE cells. Coimmunoprecipitation of acetyl-histone H3(Lys14)/IKKα was evaluated in 16HBE cells treated with rhIL-17A and in the presence of the drug. TSLP and IL-17A levels were higher in ISs from COPD patients and HS compared with HC. TSLP protein and mRNA increased in 16HBE cells and in normal bronchial epithelial cells stimulated with ISs from COPD patients compared with ISs from HC and untreated cells. IKKα silencing reduced TSLP production in 16HBE cells stimulated with rhIL-17A and ISs from COPD patients. RhIL-17A increased the IKKα/acetyl-histone H3 immunoprecipitation in 16HBE cells. The anticholinergic drug affects TSLP protein and mRNA levels in bronchial epithelial cells treated with rhIL-17A or with ISs from COPD patients, and IKKα mediated acetyl-histone H3(Lys14). IL-17A/IKKα signaling induced the mechanism of chromatin remodeling associated with acetyl-histone H3(Lys14) and TSLP production in bronchial epithelial cells. Anticholinergic drugs might target TSLP derived from epithelial cells during the treatment of COPD.

Crosstalk between mAChRM3 and β2AR, via acetylcholine PI3/PKC/PBEP1/Raf-1 MEK1/2/ERK1/2 pathway activation, in human bronchial epithelial cells after long-term cigarette smoke exposure

BACKGROUND

Cigarette smoke extract (CSE) affects the expression of non-neuronal components of cholinergic system in bronchial epithelial cells and, as PEBP1/Raf-mediated MAPK1/2 and ERK1/2 pathway, promotes inflammation and oxidative stress.

AIMS

We studied whether Acetylcholine (ACh) is involved in the mechanism of crosstalk between mAChRM3 and β2Adrenergic receptors (β2AR) promoting, via PI3/PKC/PBEP1/Raf/MEK1/2/ERK1/2 activation, β2AR desensitization, inflammation and, oxidative stress in a bronchial epithelial cell line (16HBE) after long-term exposure to cigarette smoke extract (LECSE).

METHODS

We evaluated mAChRM3 and Choline Acetyltransferase (ChAT) expression, ACh production, PEBP1, ERk1/2, and β2AR phosphorylation, as well as NOX-4, ROS production and IL-8 release in 16HBE after LECSE. The inhibitory activity of Hemicholinium (HCh-3) (a potent choline uptake blocker), LY294002 (a highly selective inhibitor of PI3 kinase), Tiotropium (Spiriva®) (anticholinergic drug) and Olodaterol (β2AR agonist), were tested in 16HBE after LECSE.

RESULTS

mAChRM3, ChAT, ACh activity, pPEBP1, pβ2AR, pERK1/2, ROS, NOX-4 and IL-8 increased after LECSE in 16HBE LECSE compared to untreated cells. HCh-3 and LY294002 (alone or in combination) as well as Tiotropium (Spiriva®) or Olodaterol (alone or in combination) all reduced the levels of pPEBP1, pβ2AR, pERK1/2, ROS, NOX-4, and IL-8 in 16HBE LECSE compared to untreated cells.

CONCLUSIONS

LECSE promotes ACh production which enhances PI3/PKC/PEBP1/Raf-ERK1/2 pathway activation, heterologous β2AR desensitization, as well as release of inflammatory and oxidative mediators in bronchial epithelial cells. The use of anticholinergic drugs and long-acting β2-agonists, alone or in combination may be dampen these inflammatory mechanisms when used in combination in some epithelial cell types.

A micromachined intensity-modulated fiber optic sensor for strain measurements: working principle and static calibration

This paper describes an intensity-modulated fiber optic sensor for strain measurements. The sensing element is a polydimetilsiloxane (PDMS) micro-diffraction grating, 15 mm long, 2 mm thick, with channels 150 µm wide, spaced apart 200 µm. The working principle of the sensor can be summarized as follows: when the sensing element is strained perpendicularly to the grating plane, light passing through the grating undergoes a modulation caused by the phenomenon of diffraction. Since the grating is interposed between a laser source and a fiber optic, the coupled radiation intensity between these two optical elements can be considered as an indirect measure of strain. A static calibration of the measuring system has been performed, showing that the device, with measuring range of about 0.04, is capable to discriminate strain of 0.005 and it presents a sensitivity increase with strain in the whole range of measurements.

Effects of gefitinib (G) on bone metatases (BMs) in non-small cell lung cancer patients

17147

Background: Selected pts with advanced NSCLC might have particular benefit from EGFR tyrosine kinase (TK) inhibitor treatment. We have identified 4 NSCLC pts with BMs who had major responses to G. Methods: Pts characteristics: Pt 1, 62 y/o female, never-smoker (ns), NSCLC, brain and BMs with bone pain; pt 2, 51 y/o male, former smoker (fs), ADC and BMs; pt 3, 51 y/o male, ns, ADC and BMs; pt 4, 50 y/o male, fs, ADC, pleural effusion, BMs and bone pain. Pts 1 and 4 had mixed osteolytic-sclerotic BMs; pts 2 and 3 had osteolytic BMs. Pts were treated with 250 mg/day of G; the dose was increased to 375 mg/day in pt 1 for maximum CNS control. Pts 1 and 4 received G as first-line therapy, pts 2 and 3 as second-line following failure of platinum-containing therapy. Pts 1–3 also received zoledronic acid. Results: Pts 1 and 4 experienced significant decrease in bone pain with G, within hours in pt 1 and by day 3 in pt 4. Pts 1–3 developed rash. Objective regression of primary tumor was observed in all 4 pts. After 3 months of G the bone scan did not change in pt 1 but many lesions became more sclerotic. Bone scans became negative after one year of treatment in pts 2 and 3. Pt 2 had resection of the primary tumor with no recurrence, 26+ months (mos) from diagnosis, 9+ mos from surgery. Pt 1 has had disease control for 7+ mos, pt 3 for 15+ mos. Pt 1 had CNS regression with G. Pt 3 was found to have asymptomatic CNS mets at 6 mos of G, received whole-brain radiation, and remains on G at >1 year. Pt 4 died 6 weeks after starting G from unrelated causes but showed dramatic BMs response by PET. Tumor tissue was available for molecular analyses for pts 2 and 4, who respectively showed EGFR-TK domain G719C mutation in exon 18 and L858R mutation in exon 21. Both mutations have been previously described in NSCLC patients responding to G. Conclusions: G may be effective in the treatment of BMs in some NSCLC patients.

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Surgical treatment of spinal deformities in Duchenne muscular dystrophy: a long term follow-up study

BACKGROUND

Surgical treatment of spinal deformities in Duchenne muscular dystrophy (DMD) is influenced by a number of factors which have proven to be a difficult challenge. Each case should be carefully evaluated, considering not only the natural history of the spinal deformity, but also the patient's general condition. These should be thoroughly assessed through clinical and radiographic investigations together with other medical specialists. Life expectancy should be determined according to the cardio-respiratory function, and both preoperative and postoperative quality of life should be taken into consideration, trying to imagine the functional status of each patient after surgery.

METHODS

From February 1985 to February 2000, 58 patients with spinal deformity in DMD were surgically treated. Of 25 patients that were operated on between 1985 and 1995, only 20 were followed-up after 5 years because 5 of them had died during this time. Therefore, the present study focuses on the results obtained in 20 cases. The 20 cases reviewed presented with a mean angular value of scoliosis equal to 48 degrees (range 10-92 degrees). Spinal fusion with our modified Luque technique [6] was performed in 19 cases, whereas CD instrumentation was applied in only one case.

RESULTS

At the 5 year follow-up (range 5.6-10 years), the age ranged from 18 to 24 years and averaged 20.4 years. The postoperative angular value of scoliosis averaged 22 degrees (58%, range 0-43 degrees), the mean correction at follow-up was 28 degrees (range 0-60 degrees), and the mean loss of correction was equal to 6 degrees (range, 0-11 degrees). Vital capacity showed a slow progression, slightly inferior to its natural evolution in untreated patients. The severest complication was the death that occurred in one of the patients.

CONCLUSIONS

According to the present study, an early surgery (angular value lower than 35-40 degrees) dramatically reduces the rate of risk factors associated with spinal deformities in DMD, and its advantages far exceed the disadvantages, above all in terms of quality of life.

Corrective osteotomy for the treatment of genu procurvatun. Surgery

The authors present the method known as proximal tibial osteotomy for the treatment of genu procurvatum. The importance of an accurate preoperative study, particularly aimed at avoiding negative repercussions on the position of the patella, and of a correct anatomical exposure with isolation of the peroneal nerve for any iatrogenic lesions, must be emphasized; a condylic plate was used to stabilize osteotomy was stabilized, adapting well to the anatomy of the region, and allowing us to obtain correction of any associated deformities on the frontal plane.

Chondrosarcoma as a complicating factor in Paget's disease of bone

A 65-year-old male patient with an 8-year history of poliostotic Paget's disease complained of shoulder pain that started 6 months prior to admission. An extensive lytic area was identified in the right proximal humerus along with Paget's disease. There was cortical destruction and a soft tissue mass. Following an incisional biopsy, a diagnosis of grade 2 chondrosarcoma associated with Paget's disease was made. The histologic identification of chondrosarcoma associated with Paget's disease is rare. However, the presence of a calcified matrix in a destructive lesion associated with Paget's disease should alert the radiologist and the pathologist to the possibility of a chondromatous differentiation taking place in the sarcoma associated with Paget's disease. The histologic evaluation of the lesion will form the basis for the diagnosis.

Aneurysmal bone cyst and giant cell tumor of the foot

From 1950 to 1994, 257 cases of benign bone tumors of the foot were treated at the Bone Tumor Center of the Rizzoli Institute. Aneurysmal bone cysts (ABC) and giant cell tumors (GCT) are rare and often they are misdiagnosed. To define the clinical and radiographic features useful for diagnosis, x-rays of 24 ABCs and 21 GCTs of the foot were reviewed. Adding our series to the cases reported in the literature, the only important clinical data that emerged was the average age of patients affected by ABC and GCT (15 and 27 years, respectively). ABCs localized in small tarsal bones were rare (6%), whereas 19% of GCTs were found in this site. The eccentric, round shape of a lytic lesion was more characteristic of GCT. An aggressive pattern of radiographic bone destruction was observed more frequently in GCT than in ABC (P = 0.01). Septation was seen in both tumors. Typical of ABC was a sharp and trabeculated margin, whereas GCT had an ill-defined edge with normal cancellous bone (P = 0.007). The growth of ABCs often expanded the cortex, while GCTs eroded, thinned, and broke the cortical bone (P = 0.001). A saucerized cortex was observed only in ABCs. A bony shelf was more characteristic of ABC than of GCT (P = 0.002). Pathologic fractures (67%) and joint involvement, evaluated by computed tomography and magnetic resonance imaging (83%), were more frequent in GCTs, whereas fluid levels were more frequently observed in ABCs (47%). The majority of the tumors were stage 2, but GCTs represented 70% of stage 3 aggressive lesions.

Reconstruction by Grosse-Kempf nailing in resections for bone tumor

The authors report 38 reconstruction by Grosse-Kempf nailing for resection of bone tumor; there were: intercalar resections: 16; arthrodeses of the knee: 13; arthrodesis of the ankle joint: 5; gyroplasty: 4. Massive homoplastic bone graft was used in 26 cases, in 3 of which autoplastic grafting was associated; autoplastic grafts were used exclusively in 7 cases, and a cement spacer was used in 1. Twenty-nine patients (76%) obtained satisfactory final results, but in 10 cases secondary surgery was performed for a total of 14 operations, of which 7 major (1 nail substitution and 6 vascularized fibula operations). There were 7 failures: mechanical complications: 6; infection: 1. The highest number of non-unions were observed where massive homoplastic grafting was used: intercalar reconstruction: 11; arthrodesis of the knee: 7. The results were evidently better and the incidence of complications low in cases in which autoplastic grafting was used or where gyroplasty was performed. Absolute stiffness and best possible contact are difficult to obtain with blocked intramedullary nailing. On the contrary, when autoplastic grafts are used or when gyroplasty is performed micromovements allowed the instrumentation are compatible with good consolidation.

Intramedullary osteosynthesis with Grosse-Kempf nailing for the treatment of distal fractures of the femur

The authors report the results they obtained in a homogeneous series of fractures of the distal third of the femur treated by Grosse-Kempf nailing. Of the 67 fractures (58 closed, 9 exposed) treated with closed surgery (except for 1 case treated by nailing 35 days after trauma) non-union was never observed. The two cases of delay in consolidation (one related to an infection) did not require a change in method. Bone grafting was never necessary. Only in 3 cases (2 with multiple trauma, 1 treated by open reduction) was moderate reduction in range of movement of the knee observed.

Grosse-Kempf nailing in fractures of the tibia

A series of 136 tibial fractures treated with locked Grosse-Kempf nailing is reviewed, evaluating the results according to rapidity of healing, functional recovery, and complications. Locked nailing proved so reliable that immediate mobilization was possible. There was only a 6% incidence of delayed union, including infections (3 cases, 2%) and nail breakage (2 cases, 1.5%). Several details of the operative technique that were decisive in the final result are discussed.

Syringomyelic arthropathy: a description of two cases and a review of the literature

Neurogenous arthropatHy is a rare disease. Nonetheless, every orthopaedist will sooner or later be faced with the arthropathy before the neurologic disease has been diagnosed. The authors report their study on two cases of syringomyelic arthropathy, repropose its anatomopathological, clinical and radiographic features, and discuss the etiopathogenesis, differential diagnosis and treatment of the disease.

An evaluation of the "quoad vitam" prognosis in the elderly patient with medial fracture of the femoral neck

The authors analyzed 425 consecutive cases of medial fracture of the femoral neck with the purpose of establishing a simple and practical system, and one which is easy to use, in order to evaluate this type of lesion and to compare different series of cases. Based on these criteria the death rate occurring intra-hospital and 6 months after trauma, the influence of the age factor, the type of anesthesia used and the type of treatment carried out, were evaluated. The results were as follows: The classification devised by the American Society of Anesthesiology continues to be an effective system for the evaluation of vital risk. The death rate was always directly related to age, and it was not influenced by either the type of anesthesia or the type of surgery used; however, it doubled when non-surgical treatment was used.

Acute external capsuloligamentous lesions of the knee

The authors discuss 18 cases of acute capsuloligamentous lesions of the external compartment of the knee submitted to surgical treatment. The results obtained by separately studying the progression of the various types of anatomical lesions revealed a relationship between the entity of the lesion and the results. Positive results were as follows: 100% in isolated lesions of the EC, 70% in lesions of the EC and ACL, 40% in lesions of the EC + ACL + PCL. In grade I distorsion trauma surgery is not indicated; in grade II lesions treatment is based on an objective examination in narcosis, and surgery should be performed when dynamic tests are positive; in grade III lesions surgery is always indicated. An objective examination in narcosis (rarely arthroscopy) is thus of essential importance to therapeutic indications.

Grosse-Kempf nailing in the elderly

The authors report on 30 fractures of the femur and tibia treated with the Grosse-Kempf locked nail in patients aged more than 60 years. Neither nonunion nor severe complications were observed; surgical trauma was well sustained. Functional results were particularly satisfactory; most patients began walking within the first week after fixation.

Problems related to blocked nailing in fractures of the proximal femur

The modern treatment of fractures of the proximal femur in the adult usually involves surgery. Open plating has proved to be reliable, but often involves a high percentage of complications: axial deformity, delayed union, breakage of the plate and/or screws (the risk of which increases in relation to the degree of comminution). At this site, in fact, the plate is submitted to strong flexion stress. It therefore becomes essential to associate cancellous grafts (as proposed by the AO School) (Muller et al., 1981) or a homoplastic cortical craft (as in our experience) (Zinghi and Masetti, 1982). Furthermore, open osteosynthesis is time consuming and this means considerable blood loss and a risk of infection. There are thus many reasons for preferring closed surgery, but effective stabilisation can only be obtained with blocked nailing; in fact, only metadiaphyseal screwing is capable of neutralising the rotation or axial stresses which cause deviation, instability or telescoping of the fracture (Kempf et al., 1978; Tigani et al., 1986; Zinghi et al., 1984). Osteosynthesis with Grosse-Kempf nailing is thus an effective alternative to open nailing, particularly in those fractures which would require additional bone grafting with this method. The purpose of our study was to verify the effectiveness of intramedullary osteosynthesis with Grosse-Kempf blocked nailing, in particular analysing the problems encountered in the use of this method.