Histomorphic-metric evaluation of an implant retrieved from human maxilla after 13 years.

Fixture fracture is the most catastrophic failure of implant components because it usually causes the loss of the implant. Nevertheless, the osseointegrated fractured implants represent a very useful opportunity to study in humans the effects of loading to the peri-implant bone microstructure. The aim of the present study was to evaluate the interplay between microstructure and function of the bone around an implant retrieved from human maxilla after 13 years. There was 1 fractured Dental Implant Line (sand blasted surface from a patient placed in the anterior region of the maxillary bone (2.1) after a bone augmentation procedure, and it was processed for histology. The specimen was analyzed under the scanning electron microscope (SEM), the confocal scanning laser microscope (CSLM) and brightfield light microscope (LM) equipped with circularly polarized light (CPL). The BIC rate of the implant retrieved after 13 years was (mean ±SD) 68.7 ± 3.7. The crestal bone down the implant platform damage appeared to be under modeling process. The transverse collagen fiber orientation (CFO) (mean ±SD) under the lower flank of the threads was 20.4 ± 3.5 x 10(4) pixel while the longitudinal CFO was 19.8 ± 2.8 x 10(4) pixel (P>.05). In the inter-threads region the transverse CFO (mean ±SD) was 15.0 ± 4.0 x 10(4) pixel while the longitudinal CFO was 21.4 ± 3.0 x 10(4) pixel (P>.05). The osteocytes numbers (mean ±SD) was 130 ∓ 34. Under SEM with back scattered electrons (BSE) signal the peri-implant bone appears mainly lamellar and highly mature with several osteons organized in the implant inter-threads areas. The fracture of the implant was most probably correlated to a fatigue of the material mainly associated to a damage of the internal coil. Surprisingly, it was noted a lack of implant site-specific CFO of the bone extracellular matrix facing the threaded dental implant notwithstanding the high level of BIC rate.

Histomorphometric evaluation of an immediately loaded implant retrieved from human mandible after 2 years.

The aim of the present study was to evaluate the interplay between microstructure and function of the bone around an immediately loaded implant retrieved from human maxilla after 23 months due to fracture. A spiral implant of 3.3 mm x 15 mm was placed in a male 53 years old in the anterior region of the mandible bone (4.1) and it was processed for histology. The specimen was analyzed under the confocal scanning laser microscope (CSLM) and brightfield light microscope (LM) equipped with circularly polarized light (CPL). The BIC rate was 76.7 ± 4.9 (mean ±SD). Many cement lines indicates an high remodeling rate of the bone. The transverse collagen fiber orientation (CFO) (mean±SD) under the lower flank of the thread near the tread tip was 55.2 ± 4.8 x 10(4) pixel while the longitudinal CFO was 45.8 ± 2.3 x 10(4) pixel (P<.05). In the inter-threads region the transverse CFO (mean ±SD) was 36.4 ± 2.4 x 10(4) pixel while the longitudinal CFO was 65.6 ± 6.5 x 10(4) pixel (P<.05). The osteocytes numbers (mean ±SD) was 205 ± 45 in the peri-implant bone and 144 ± 53 in the native bone (P=.007). After 2-years of loading the SLA spiral implant was well osseointegrated but still surrounded by woven bone. The osteocytes density was significantly higher in the peri-implant bone than in the native bone. The transverse collagen fibers were significantly associated with the lower flank of the implant threads, while the longitudinal collagen fibers were more represented in the straight surface of the implant. The implant fracture was correlated to crestal bone resorbing and subsequent fatigue yielding.

Calcium sulfate stimulates pulp stem cells towards osteoblasts differentiation.

Calcium sulfate (CaS) is a highly biocompatible material and enhances bone formation in vivo. However, how CaS alters osteoblast activity to promote bone formation is poorly understood. To study how CaS can induce osteoblast differentiation in mesenchymal stem cells, the expression levels of bone related genes and mesenchymal stem cells marker were compared in normal osteoblasts and dental pulp stem cells, using real time Reverse Transcription-Polymerase Chain Reaction. Gene differentially expressed between the two cells type were the trascriptional factor RUNX2, osteopontin (SPP1), COL1A1 (collagen type 1α1) and alkaline phosphatase (ALPL). The obtained results demonstrated that CaS strongly influences the behavior of DPSCs in vitro enhancing proliferation, differentiation and deposition of matrix.

Polylactide-polyglycolide resorbable plates stimulates adipose tissue-derived stem cells towards osteoblasts differentiation.

Polylactide, polyglycolide materials or devices have been utilized routinely during maxillofacial, craniofacial, and orthopaedic reconstructive surgical procedures.(1) These materials combine the benefits of rigid fixation with the advantages of biodegradation, avoiding the need for implant removal and minimizing the risk of other complications.(2) To study how polylactide, polyglycolide acids plates (PLPG plates) can induce osteoblast differentiation and proliferation in mesenchymal stem cells, the expression levels of bone related genes (RUNX2, SP7, ALPL, SPP1, COL1A1, COL3A1 and FOSL1) and mesenchymal stem cells marker (ENG) were measured in adipose derived stem cells (ADSCs) and normal osteoblast (NO) cultivated on PLPG plates after 15 and 30 days of treatment using real time Reverse Transcription-Polymerase Chain Reaction. Significantly differentially expressed genes among ADSCs and NO were SP7, ENG, FOSL1, RUNX, ALPL and SPP1 in the first 15 days of treatment and SP7, ENG FOSL1, COL3A1 COL1A1, SPP1 and ALPL after 30 days. The present study demonstrated that PLPG plates strongly influences the behavior of ADSCs in vitro by enhancing proliferation, differentiation and deposition of matrix.

Overdentures on implants placed in bone augmented with fresh frozen bone.

AIM: In the last decade several studies have been performed to evaluate the clinical outcome of one or two stage loaded implants supporting overdentures. Since fresh frozen bone (FFB) has an ever-increasing number of clinical applications and few reports are available on implants inserted into FFB, we performed a retrospective study on fixtures inserted in FFB and bearing overdentures. METHODS: In the period between December 2003 and December 2006, 17 patients (14 females and 3 males with a median age of about 56 years) were grafted and 60 implants inserted thereafter. A total of 17 overdentures were delivered: 8 in the mandible and 9 in the maxilla. Multiple implant systems were used: 22 Double etched, 7 SLA, 9 Anodic oxidized, and 22 CaPo4 ceramic-blasted. Implant diameter ranged from 3.25 to 4.3 mm and length from 11.5 to 16.0 mm. Implants were inserted to replace 23 incisors, 9 cuspids, 20 premolars and 8 molars. RESULTS: No implants were lost (i.e., survival rate=100%) and no differences were detected among the studied variables. Kaplan Meier algorithm and Cox regression did not reveal any statistical differences among the studied variables also as regards the success rate. CONCLUSION: Implants inserted FFB and bearing overdentures have a high survival rate and success rates, which are comparable to those of implants inserted in non-grafted bone. FFB bone is a reliable material for alveolar ridge augmentation. No difference was detected among removable prostheses supported by two or more implants.

In vitro effects of concentrated growth factors (CGF) on human SH-SY5Y neuronal cells.

OBJECTIVE: The aim of this study was to test the in vitro differentiation effects of concentrated growth factors (CGF), a platelet rich preparation, using SH-SY5Y cells, derived from human neuroblastoma. MATERIALS AND METHODS: SH-SY5Y cells were cultured in presence of CGF or retinoic acid (RA). After 72 h of treatment, different parameters were investigated: cell proliferation by an automated cell counter; cell viability by thiazolyl blue tetrazolium bromide (MTT) assay; cell differentiation markers, i.e., neuronal nuclear antigen (NeuN), synaptophysin (SYP) and ß3-tubulin, by immunocytochemistry and Western blotting techniques; release of nerve growth factor (NGF) and brain-derived growth factor (BDNF) by enzyme-linked immunosorbent assay (ELISA) and neurite outgrowth by a dedicated image software. RESULTS: In presence of CGF, the cell proliferation rate and viability decreased, as expected for differentiated SH-SY5Y cells. On the contrary, the cellular differentiation markers increased their expression together with the release of growth factors. Moreover, the neurite outgrowth was improved. CONCLUSIONS: The data suggest that CGF treatment positively affects the cell differentiation, regulating the expression of neuronal markers, the release of growth factors and the neurite length. Taken together these results seem to be promising in the development of new approaches for neural regeneration.

Restoration of locomotion in posttraumatic paraplegics: the multidisciplinary approach and unexpected plasticity of single neurons--facts and fantasy.

In Europe there are about 300,000 paraplegics and in every country approximately 1000 new cases per year. Treatment requires a multidisciplinary approach with scientific cooperation targeted to exchange personal knowledge and expertise. At present a completely disrupted spinal cord cannot heal for recovery of motor and/or sensory functioning, although some promising treatment modalities in laboratory animal experiments have been reported. No interventional stem cell procedure so far has shown evidence to restore impaired functioning in human paraplegics. However, functional electrical stimulation (FES) via an implanted neuroprosthesis (SUAW concept) and central nervous system-peripheral nervous system (CNS-PNS) connection have successfully been used for alternative compensatory strategies for voluntary locomotion. This report is to analyse the authors' experience from two European projects in paraplegic. Factors will be identified that might have caused the one or other pitfall since so far both surgical reconstructive procedures have not been adopted by rehabilitation physicians and/or restorative (neuro-)surgeons despite the promising functional results we have achieved. Unexpected plasticity of single neurons following CNS-PNS by-pass procedures is discussed. Future interventions, for example the present phase 1 prospective multiple centre study on the side effects, effectiveness, and reliability of intrathecal treatment of anti-Nogo-A antibodies, are presented and the Chinese stem cell implantation is critically reviewed.

Adhesion reduction after knee surgery in a rabbit model by Hyaloglide, a hyaluronan derivative gel.

A randomized controlled experimental trial was performed in a rabbit model of surgical adhesions to investigate the anti-adhesive effects of Hyaloglide, a highly viscous hyaluronan derivative absorbable gel after knee surgery. Twenty New Zealand white rabbits were prepared and randomly divided into two groups of 10 animals each. An intra-articular fibro-adhesive scar was created in the right knee joint of the hind paw of each rabbit using a standardized surgical procedure, and Hyaloglide was administered into the joint cavity of the knee at the end of intervention in the animals belonging to the treatment group. No anti-adhesive treatment was applied in the control group. Additionally, immobilization using a Kirschner wire was applied in order to increase the risk of adhesions. Six weeks after surgery the animals were euthanized and after removal of the immobilization system, adhesions were evaluated both macroscopically and histologically. Results of gross observations using a specific adhesion scoring system showed a significant reduction (p<0.01) of both incidence and severity of adhesions in the hyaluronan-treated group compared to the control group. Histologically, adhesions in the treated group were thinner with less collagenic fibers. In conclusion, Hyaloglide may be considered as a promising absorbable barrier for prevention of post-operative fibrotic adhesions after knee surgery.

Brachial plexus surgery (honorary lecture).

Brachial plexus injuries (B.p.i.) are lesions occurring more and more frequently due to high velocity road and sport traumas. They are severe lesions with disabling sequelae. Surgical procedures and results could greatly be improved in the last 2 decades. Although the anatomy of brachial plexus is well known, less known are the functional maps of the various brachial plexus elements. In this paper treatment modalities for obstetrical, traumatic (adult) and actinic B.p.i. are being described too.

Clonazepam serum protein binding during development.

Clonazepam protein binding was investigated in sera from five different umbilical cords, 45 children (aged 2 mo to 12 yr), and five adults (aged 27 to 40 yr). The unbound fraction (means +/- SE) of clonazepam was 17.3% +/- 0.7% in umbilical cord serum and 13.9% +/- 0.2% in adult serum (P less than 0.01). In children, the unbound fraction of clonazepam reached the adult values during the first year of life. The kinetics of clonazepam serum protein binding were studied in three umbilical cord serum and three adult serum specimens. The number of binding sites (n, reported as moles per gram protein) and the association constant (K, reported as M-1) were estimated from double reciprocal plots of 1/r against 1/D (r is the number of moles bound per gram plasma protein; D is the molar concentration of unbound drug). In umbilical cord sera, the mean values (+/- SE) of n and K were 8.4 +/- 0.6 X 10(-7) mol/gm and 8.3 +/- 0.9 X 10(4) M-1. In adult serum samples the corresponding values were 3.0 +/- 0.8 X 10(-7) mol/gm and 2.7 +/- 0.6 X 10(5) M-1, which indicated lower binding capacity but higher affinity for clonazepam of plasma proteins in adults than in children.

Coupling between "hand" primary sensorimotor cortex and lower limb muscles after ulnar nerve surgical transfer in paraplegia.

Previous neuroimaging evidence revealed an "invasion" of "hand" over "lower limb" primary sensorimotor cortex in paraplegic subjects, with the exception of a rare patient who received a surgical motor reinnervation of hip-thigh muscles by the ulnar nerve. Here, the authors show that a functional reorganization of cortico-muscular and cortico-cortical oscillatory coupling was related to the recovery of the rare patient, as a paradigmatic case of long-term plasticity in human sensorimotor cortex after motor reinnervation of paraplegic muscles. This conclusion was based on electroencephalographic and electromyographic data collected while the patient and normal control subjects performed isometric muscle contraction of the left hand or lower limb. Cortico-muscular and cortico-cortical coupling was estimated by electroencephalographic-electromyographic coherence and directed transfer function of a multivariate autoregressive model.

Bradykinin and substance P potentiate acetylcholine-induced bronchospasm in guinea-pig.

The interaction of threshold doses of bradykinin (BK) and substance P (SP) with acetylcholine (ACh)-induced bronchospasm was investigated in anaesthetized guinea-pigs. The two peptides potentiated the ACh-induced bronchospasm, an effect which did not seem to depend on prostaglandin release. On the other hand, vagotomy abolished the capacity of BK and SP to potentiate the ACh-induced bronchospasm. The present data suggest a possible involvement of BK and SP in the genesis of airway hyperreactivity.

Remodelling of sensorimotor maps in paraplegia: a functional magnetic resonance imaging study after a surgical nerve transfer.

The adult mammalian brain has the capacity of reorganising its neural connections in response to lesions/modifications of the peripheral and central nervous system. We show in vivo, using functional magnetic resonance imaging (fMRI), that in paraplegics the lower-limb sensorimotor cortex is invaded by the arm representation. This functional reshaping appears to be reversible. Indeed, surgical transfer of the ulnar nerve to the ipsilateral quadriceps and hip muscles allowed their contraction in a paraplegic patient. During fMRI, these voluntary movements activated the hip and thigh representation in sensorimotor cortex. We suggest that the functional recovery of the lower-limb functional maps might have been driven by the restored somatosensory inputs from the reactivated periphery. The voluntary movements of the lower-limbs are regained through the 're-awakening' of the corresponding sensorimotor cortex.

Acute cholecystitis: ultrasonographic staging and percutaneous cholecystostomy.

Experience in the treatment of acute cholecystitis with percutaneous cholecystostomy in 29 high-risk and elderly patients is reported. The treatment group included 14 men and 15 women, 21 of whom were over 70 years of age. The suspected clinical diagnosis of acute cholecystitis was confirmed in all cases by ultrasonography (accuracy: 95.6%). The percutaneous cholecystostomy was successful in 27 of 29 cases and these patients had a sudden improvement in their clinical condition; failure of the procedure was due in one patient to dislodgement of the catheter and in another patient to the guide-wire slipping out of the gallbladder. Six patients complained of pain radiating to the right shoulder which disappeared within 30-60 minutes after the procedure. Twenty-three of the 27 patients subsequently underwent elective cholecystectomy. In 22 patients the ultrasonographic findings were compared with the histology; thus enabling us to establish an ultrasonographic staging of acute cholecystitis related to the seriousness of the disease. Percutaneous cholecystostomy is the treatment of choice in high-risk patients, in the elderly, as well as in young patients with impending perforation.

Neurotization of avulsed roots of brachial plexus by means of anterior nerves of cervical plexus.

In summary, this technique provides a number of well-differentiated sensory and voluntary motor fibers. This number is certainly less than that of a normal plexus but is much more and of much better quality than that of intercostal nerves. If we distribute these fibers to well-chosen branches of the brachial plexus, limiting the neurotization to few selective components, we have the possibility of a useful recovery of essential movements of the shoulder and elbow. Sensation to the hand will also recover to a certain extent. Subsequent palliative operations (as for instance different kinds of arthrodesis) can supply a limb that, although paralyzed and severely impaired, can still be useful.

Restoration of locomotion in paraplegics with aid of autologous bypass grafts for direct neurotisation of muscles by upper motor neurons--the future: surgery of the spinal cord?

OBJECTIVES: Paraplegia means a lifelong sentence of sensory loss, paralysis and dependence. Complete spinal cord lesions cannot heal up to now despite intensive experimental research, remarkable efforts and recent achievements in bio-technology and re-engineering. Traumatic paraplegia due to spinal cord injury (SCI) is a quite frequent condition and related to the socio-economical situation of the population. It is experienced disproportionately by young people. The rise in gunshot wounds is dramatic. SCI has appeared refractory to treatment. PATIENTS AND METHODS: Since 1980 G.A.B. had tried surgical repair of the spinal cord (SC) after experimental bisection in rats, and since 1993 research was done on monkeys (macaca fascicularis) to be closer to human physiology. The sciatic nerve was removed and used as an autologous graft from the lateral bundle of the spinal cord (tractus corticospinalis ventro lateralis) to the three muscles of both legs being known to be most important for locomotion: M. gluteus maximus, M. gluteus medius and M. quadriceps femoris. The first fruitful transplantation in a human being was performed in July 2000. RESULTS: The results in rats were promising and fulfilled the requirements of the American Task Force of the National Institute of Neurological and Communicative Disorders and Stroke of the US. The results in monkeys confirmed the paradigm so that we performed the first operation in a young lady suffering for four months from complete SC lesion T9 after approval by the ethical committee. First voluntary movements of the connected muscles after 17 months. 27 months after op she was able to walk up to 60 steps with the help of a walker and to climb steps in the water. Improvement is still continuing. DISCUSSION: SCI has appeared refractory to any kind of treatment. Compensatory strategies are still experimental in human beings. Autologous nerve grafts from the spinal cord tissue (the lateral spinal bundle) connected to peripheral muscle nerves seem promising in paraplegics. But the physiology is still unclear when the glutamatergic upper motor neuron connected to motor end-plates (cholinergic) does work like in our patient. CONCLUSION: Further studies in primates and paraplegic patients are necessary to clarify the bypass grafting of the SC to muscle groups distal to the complete SCI to restore locomotion.

Computer added locomotion by implanted electrical stimulation in paraplegic patients (SUAW).

Paraplegia means a live long sentence of sensory loss, paralysis and dependence with approximately 1000 new victims in every European country every year and 11.500 new traumatic SCI cases in the US. respectively. Sixty percent are injured before age 30. More than 90% of SCI victims may survive with nearly normal experience of live. Most patients will recover somewhat from SCI over time but no patient who remained plegic for one year regains voluntary motor function after that time period. Despite remarkable efforts and recent achievements in rehabilitation no treatment can be recommended so far to enhance functional recovery and restoring locomotion in paraplegic humans. FES as a technical compensation has become therefore a challenging treatment to restore muscle function and to prevent atrophy and to improve mobility and quality of life at the same time. In paraplegics FES could be the basis to restore locomotion. One of the advantages of an implanted FES version (neuroprosthesis) is that the FES system, electrodes, and cables remain permanently implanted within the body, so that the patient can stay without cables, the programmer attached to the crutches. The SUAW project, supported under BIOMED II Programme by the European Community was aimed to finalize and to put into practice the results of previous research and development. The novel implant with an ASCI-Chip has 16 channels, 8 on each side, 20 mA for monopolar and 2 mA for bipolar stimulation, only one electrode can be stimulated at a given time. Stimulation of 6 muscle groups of both legs are known to be sufficient for locomotion: M. ileopsoas (erector of the body, hip flexor), M. gluteus maximus (hip extensor), M. gluteus medius (lateral hip stabilisator, knee abductor), Mm. hamstrings (knee flexor) stimulated by epimysial electrodes, Mm. sartorius and rectus femoris (knee extensor) stimulated by neural, bipolar electrodes. Patient's selection criteria were: stable spinal cord lesion between T7 and T11, minimum 1 year after the accident without deformity of the spine, the muscle groups for locomotion responding to external FES with the EXOSTIM programmer with the same programme used later for the neuroprosthesis. Two paraplegic male patients, T8, 38 and 31 years old respectively, were operated on by an international group of surgeons according to the protocol in 09/1999, respectively 7/2000. The postop. course was uneventful. Because the threshold of the primary implant was too low regarding scare tissue around the electrodes, this implant was changed in 01/2000 and worked perfectly. Both patients are happy with the success of the novel treatment modalities.

Tissue changes at different periods of ischemia.

A multidisciplinary study was done to examine the following: (a) pathophysiological changes in muscle and nerve response following different periods of normothermic and cold ischemia; (b) alterations in the release of enzymes (K, LDH), CA++, K=and lactate under these conditions; and (c) histological alterations of vessels, nerves and muscles after different periods of normothermic and cold ischemia. The results demonstrate that hypothermic ischemia greatly reduces both the leakage of enzymes, cellular damage and pathological responses. We infer that amputated parts containing muscular masses may be replanted with good prognosis for satisfactory functional results within 4-5 hours at room temperature. By reducing the temperature, the time between cooling and revascularization may be doubled. Parts without muscles may be replanted 10-12 hours after normothermic ischemia and up to 24 hours or even longer after cold ischemia.

A personal technique for treatment of scaphoid non-union.

We describe a personal technique for the treatment of scaphoid non-union, consisting of styloidectomy of the radius associated with axial perforation of the scaphoid, emptying of the bone, filling it again by cancellous bone taken from the styloid and securing it with a peg obtained from the cortex of the same styloid. 52 patients out of 77 operated on with this technique were reviewed. Results are shown and seem to be better than those found in literature.