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Biomedical subjects

M F Basle

Publications and source records attributed to M F Basle.

At least 19 recordsLinked to original sources
PubMed2004

[Study of two types of dental implants for immediate loading (expansion implants and locking pin implants) in the Beagle dog].

Titanium implants have become a treatment of choice for total or partially edentulous patients. The method, however, requires a double surgical time and the placement of the dental prosthesis after a healing phase of 3 to 6 months during which the patients have a toothless mandible with the top of the implants emerging at the gengiva. Immediate loading of standard implants is responsible for micromotions which induce implant failure. New designs of implants would allow an immediate anchoring in the bone, would prevent the shearing forces and would precociously authorize the setting of the prosthesis. We made an experimental study in the Beagle dog. After partial tooth removal, two types of implants were placed (expansion implants and locking pin implants). After 2 weeks, the implants were covered with a gold-palladium prosthesis and left in place during 12 weeks. After sacrifice, a study by resonance frequency (ISQ) and histomorphometry was done. The two types of implants were covered by the same quantity with bone (volume and interface) without interposition of fibrous tissue. The locking pin implants were associated with an increase in the ISQ parameter of stability, higher than that of the expansion implants. The locking pin implant, tested in the dog which has a chewing function close to man, appears interesting for the immediate loading with dental prosthesis.

Animals↗
PubMed2002

Non-connected versus interconnected macroporosity in poly(2-hydroxyethyl methacrylate) polymers. An X-ray microtomographic and histomorphometric study.

Poly(2-hydroxyethyl methacrylate) (pHEMA) has potentially broad biomedical applications: it is biocompatible and has a hardness comparable to bone when bulk polymerized. Porous biomaterials allow bone integration to be increased, especially when the pores are interconnected. In this study, three types of porogens (sugar fibers, sucrose crystals, and urea beads) have been used to prepare macroporous pHEMA. The pore volume and interconnectivity parameters of the porosity were measured by X-ray microtomography and image analysis. Sucrose crystals, having a high volumetric mass, gave large pores that were located on the block sides. Urea beads and sugar fibers provided pores with the same star volume (2.65 +/- 0.46 mm3 and 2.48 +/- 0.52 mm3, respectively) but which differed in interconnectivity index, fractal dimension, and Euler-Poincarés number. Urea beads caused non-connected porosity, while sugar fibers created a dense labyrinth within the polymer. Interconnectivity was proved by carrying out surface treatment of the pHEMA (carboxymethylation in water), followed by von Kossà staining, which detected the carboxylic groups. Carboxymethylated surfaces were observed on the sides of the blocks and on the opened or interconnected pores. The disconnected pores were unstained. Macroporous polymers can be prepared with water-soluble porogens. X-ray microtomography appears a useful tool to measure porosity and interconnectedness.

Biocompatible Materials↗
PubMed2001

Texture analysis of X-ray radiographs is a more reliable descriptor of bone loss than mineral content in a rat model of localized disuse induced by the Clostridium botulinum toxin.

Botulism is a generalized paralyzing disease caused by the toxin of Clostridium botulinum (BTX). The toxin acts 3-4 days after injection by blocking the release of acetylcholine to the muscle. Six Wistar rats received a 2-U injection of BTX in the right quadriceps. Six rats were similarly injected with saline and were used as control. Paralysis of the quadriceps was obtained 4-5 days after the injection. Animals were killed 4 weeks after the BTX injection. The bone mineral content (BMC) was measured by dual-energy X-ray absorptiometry (DXA) on the femur and tibia. No side-to-side difference was observed for BMC on the whole tibia and femur in the BTX group. When subregions were selected in the bones, a significant decrease in BMC was obtained on the proximal tibia (-17.4 +/- 2.5%, p < 0.02). No significant difference could be observed on the proximal or distal femur, nor on the diaphyseal shafts. Numeric X-rays were done and a region of interest was transferred to an image analyzer. The texture of the trabecular bone was analyzed by the run length and fractal methods (skyscrapers and blanket). Significant differences were obtained on the proximal tibia for all methods except with fractal skyscrapers. On the distal femur, significant differences were obtained with the run length method, and the skyscrapers and the blanket method in the vertical direction. No differences were obtained with any method on the tibia and femur from control animals. Bone is a highly anisotropic material and its architecture at the microscopic level is conditioned by strains. The trabecular pattern differs in the proximal tibia than in the distal femural. Depending on the trabecular anisotropy, the algorithms can be more or less pertinent. BTX induced a significant bone loss on the bony subparts that are directly influenced by disuse. Texture analysis of X-ray images can reveal differences that were not evidenced by naked eyes. However, a combination of several methods appears necessary to appreciate the bone loss.

Absorptiometry, Photon↗
PubMed2000

Trabecular bone microarchitecture, bone mineral density, and vertebral fractures in male osteoporosis.

Some studies have indicated that the risk of fragility fractures in men increases as bone mineral levels decrease, but there is an overlap in the bone mineral density (BMD) measurements between patients with or without fractures. Furthermore, it has been suggested that the biomechanical competence of trabecular bone is dependent not only on the absolute amount of bone present but also on the trabecular microarchitecture. In the present study, 108 men (mean age 52.1 years) with lumbar osteopenia (T score < -2.5) were recruited to examine the relationships between BMD, architectural changes in trabecular bone, and the presence of vertebral fractures. Lumbar BMD was assessed from L2 to L4 in the anteroposterior view with dual-energy X-ray absorptiometry. At the upper left femur, hip BMD was measured at the transcervical site. Spinal X-ray films were analyzed independently by two trained investigators, and vertebral fracture was defined as a reduction of at least 20% in the anterior, middle, or posterior vertebral height. Transiliac bone biopsy specimens were obtained for all patients. Histomorphometric studies were performed on an image analyzer, and the following parameters were determined: trabecular bone volume (BV/TV), trabecular thickness (Tb.Th), number (Tb.N), and separation (Tb.Sp), interconnectivity index (ICI), characterization of the trabecular network (node count and strut analysis), and star volume of the marrow spaces. Spinal radiographs evidenced at least one vertebral crush fracture in 62 patients (group II) and none in 46 patients (group I). After adjusting for age, body mass index, and BMD, there were no significant differences between the two groups in BV/TV, Tb.Th, or star volume. In contrast, the mean values of ICI, free end-to-free end struts (FF/TSL), and Tb.Sp were significantly higher, whereas Tb.N and node-to-node struts (NN/TSL) were lower in patients with at least one vertebral fracture. Logistic regression analysis showed that only ICI, FF/TSL, NN/TSL, and Tb.N were significant predictors of the presence of vertebral fracture: odds ratios for an alteration of 1 SD ranged from 1.7 (1.0-3.2) for NN/TSL to 3.2 (1.1-10.1) for ICI. Patients with at least three vertebral fractures (n = 23) were categorized as "multiple fractures." The results of logistic regression showed that spine BMD, BV/TV, and all architectural parameters were significant predictors of multiple vertebral fractures: odds ratios for an alteration of 1 SD ranged from 2.2 (1.1-4.6) for star volume to 3.7 (1.4-9.7) for ICI. These results strongly suggest that bone trabecular microarchitecture is a major and independent determinant of vertebral fractures in middle-aged men with osteopenia.

Absorptiometry, Photon↗
PubMed2000

[Osteoporosis in males].

A shorter life expectancy, a higher peak bone mass and the absence of distinct menopause equivalent explain the lower incidence of osteoporotic fractures in men. In contrast to women, osteoporosis in younger men is in most cases secondary. Causes such as prolonged glucocorticoid therapy, ethanol abuse, hypogonadism and gastrointestinal disorders are now well recognized. The impact of cigarette smoking, low calcium intake, vitamin D deficiency, hypercalciuria and thyrotoxicosis is more controversial but seems to constitute real risk factors for bone loss. Furthermore increased propensity to fall also plays a major role in fracture risk, particularly in alcoholic patients and in elderly men with neurologic disorders.

Age Distribution↗
PubMed1999

Bone mineral density and vertebral fractures in men.

In women, many studies indicate that the risk of vertebral fragility fractures increases as bone mineral density (BMD) declines. In contrast, few studies are available for BMD and vertebral fractures in men. It is uncertain that the strength of the relationship between BMD and fractures is similar in magnitude in middle-aged men and in postmenopausal women. In the present study, 200 men (mean age 54.7 years) with lumbar osteopenia (T-score < -1.5) were recruited to examine the relationships between spine BMD and hip BMD and the associations of BMD with vertebral fractures. Lumbar BMD was assessed from L2 to L4, in the anteroposterior view, using dual-energy X-ray densitometry. At the upper left femur, hip BMD was measured at five regions of interest: femoral neck, trochanter, intertrochanter, Ward's triangle and total hip. Spinal radiographs were analyzed independently by two trained investigators and vertebral fracture was defined as a reduction of at least 20% in the anterior, middle or posterior vertebral height. Spinal radiographs evidenced at least one vertebral crush fracture in 119 patients (59.5%). The results of logistic regression showed that age, femoral and spine BMDs were significant predictors of the presence of a vertebral fracture. Odds ratios for a decrease of 1 standard deviation ranged from 1.8 (1.3-2.8) for spine BMD to 2.3 (1.5-3.6) for total hip BMD. For multiple fractures odds ratios ranged from 1.7 (1.1-2.5) for spine BMD to 2.6 (1.7-4.3) for total hip BMD. In all models, odds ratios were higher for hip BMD than for spine BMD, particularly in younger men, under 50 years. A T-score < -2.5 in the femur (total femoral site) was associated with a 2.7-fold increase in the risk of vertebral fracture while a T-score < -2.5 in the spine was associated with only a 2-fold increase in risk. This study confirms the strong association of age and BMD with vertebral fractures in middle-aged men, shows that the femoral area is the best site of BMD measurement and suggests that a low femoral BMD could be considered as an index of severity in young men with lumbar osteopenia.

Absorptiometry, Photon↗
PubMed1999

[Histomorphometric measurement of the architecture of the trabecular bone in osteoporosis: comparative study of several methods].

Osteoporosis is now defined as a disease characterized by a decreased bone mass associated with micro-architectural modification of trabecular bone leading to an increased fragility and to bone fractures. Various histomorphometric methods have been described to measure bone architecture on histological sections. However, not all of methods are strictly equivalent and some of them appear able to detect differences earlier in the course of the disease. We have compared 8 histomorphometric methods known to characterize the architecture of trabecular bone in 55 male osteoporotic patients. Measurements were done on transiliac bone biopsies: Trabecular number, thickness and separation (Tb.N, Tb.Th, Tb.Sp); Trabecular Bone Pattern Factor (TBPf); Euler-Poincaré's number (E); Interconnectivity Index (ICI); strut analysis of the trabecular network with the ratio of nodes/free-end (N/F); star volume of the bone marrow (Vm) and trabeculae (Vtrab) and the Kolmogorov fractal dimension of the trabecular boundaries (D). Relationships between the various architectural parameters were studied by hierarchical cluster analysis. Linear, hyperbolic and exponential correlations were found between trabecular bone volume (BV/TV) and architectural parameters. Cluster analysis demonstrates the link between these architectural parameters. ICI, E and TBPf which reflect the amount of open/closed marrow cavities clustered together and appeared related to Tb.Sp, which are indicators of the mean size of marrow cavities. Tb.Th, Vm and N/F flocked together as they reflect the trabecular size. Tb.N and D segregated together and seemed to best describe the trabecular network complexity. These histomorphometric techniques are correlated but correlations may be linear or non linear. Several histomorphometric techniques need to be used in parallel to appreciate the pathophysiological mechanisms of osteoporotic states.

Bone and Bones↗
PubMed1999

[Trabecular bone microarchitecture and male osteoporosis].

In men the risk of fragility fractures increases as bone mineral density (BMD) declines but the mechanical strength of vertebrae is also dependent on the trabecular architecture. We have examined the relationships between architectural changes of trabecular bone and vertebral crush fractures in 44 male patients with osteoporosis (bone mineral density more than 2.5 SD below the young adult value). Spine radiographs, hip and lumbar spine BMD and transiliac bone biopsies were obtained for all subjects. Histomorphometric study was done on an image analyzer and the following parameters were determined: trabecular bone volume (BV/TV), trabecular thickness (Tb.Th) and number (Tb.N), Trabecular Bone Pattern factor (TBPf), Inter Connectivity Index (ICI), characterization of the trabecular network (Node count and Strut analysis) and Star volume of the marrow space. Eleven male patients, who were referred to our unit for the diagnosis a monoclonal gammopathy of undetermined significance, were selected as controls. The mean values of Tb.Th, Tb.N and Node count were found lower while TBPf, ICI and Star Volume were significantly higher in men with osteoporosis. Exponential regressions were found to best describe the relationships between BV/TV and the architectural parameters: TBPf (r = 0.94 p = 0.01), ICI (r = 0.63 p = 0.001), Star volume (r = 0.79 p = 0.001). There were no significant differences in age, vertebral and hip BMD, BV/TV and Tb.Th between patients with or without fracture. In contrast, in patients with at least one vertebral fracture, ICI and TBPf were significantly higher while Nodecount was lower. Our data suggest that an altered trabecular bone architecture is a major determinant of osteoporotic fractures in men.

Adult↗
PubMed1996

Expression of prolactin receptors in human osteosarcoma cells.

The expression of prolactin receptor (PRL-R) mRNA was demonstrated by reverse transcription-polymerase chain reaction (RT-PCR) combined with Southern analysis in total RNA extracts from two human osteosarcoma cell lines (MG-63 and Saos-2). The level of PRL-R transcript was significantly enhanced in cells cultured in the presence of 1,25-(OH)2 vitaminD3 (10(-7)M) and to a lesser extent in the presence of dexamethasone (10(-6)M). This first demonstration of PRL-R gene expression in osteoblast-like cells supports the hypothesis of a direct action of prolactin in bone cells, which is further strongly suggested by the stimulatory effect of 1,25-(OH)2 vitaminD3 and dexamethasone on PRL-R mRNA level in these cells.

Bone and Bones↗
PubMed1996

Quantifiable excess of bone resorption in monoclonal gammopathy is an early symptom of malignancy: a prospective study of 87 bone biopsies.

To determine if excessive osteoclastic-mediated bone resorption (BR) is an early tumor-induced event in multiple myeloma (MM), BR was assessed at first presentation on quantitative bone biopsy in 87 individuals evaluated for monoclonal gammopathy of undetermined significance (MGUS) and reinterpreted according to the presenting features and subsequent follow-up evaluation. As a reference population, 48 patients with previously untreated overt MM were evaluated under similar conditions. The median level of BR was significantly higher in 48 overt MM versus 87 MGUS patients (12.2% v 5.1% [normal level, <6%], P <.01). Actually, 93% of overt MM patients had an excessive BR versus 45% of MGUS patients at presentation (P <.01) According to simple presenting parameters (> or <5% plasma cells within the bone marrow, presence or absence of mild anemia/neutropenia), 31 individuals were classified as low-risk MGUS, 32 high-risk MGUS, and 24 indolent MM. An excessive BR was observed in 16% of low-risk MGUS, 46% of high-risk MGUS (P <.01 v low-risk MGUS), 79% of indolent MM (P <.05 v high-risk MGUS), and 93% of overt MM patients. Of major interest, the level of BR in indolent MM (11.2%) was identical to that in overt MM (12.2%) but significantly higher than in both low-risk (4%, P <.01) and high-risk (5.6%, P <.01) MGUS. When considering the follow-up evaluation of MGUS patients, an excessive BR at presentation was observed in 52% of MGUS cases that turned out to be unstable or developed subsequent MM, but in only 4% of stable MGUS (P <.01). More precisely the level of BR of low-risk MGUS that either turned out to be unstable or that developed into MM was significantly higher at presentation than that of subsequent stable MGUS (4.4% v 2.9%, P <.05). The same difference was observed in both high-risk MGUS and indolent MM according to subsequent follow-up studies (8.1% v 3.4% and 11.7% v 6%, respectively, P <.05). Of major interest, the level of BR in 11 stable high-risk MGUS cases actually fulfilling the diagnostic criteria of smoldering MM was very low (3.4%) and similar to that in stable low-risk MGUS (2.9%). We conclude that a quantifiable excess of BR in MGUS is significantly associated with progression and thus is an early symptom of malignancy in these individuals.

Anemia↗
PubMed1996

[Viral origin of Paget's disease of bone?].

The viral aetiology of Paget's bone disease was suspected by the finding, in 1974, of microcylindric paramyxovirus nucleocapsid-like inclusions in nuclei and cytoplasm of pagetic osteoclast. Paramyxovirus antigens were detected, using monoclonal antibodies, in the osteoclasts of pagetic lesions. Paramyxovirus RNA sequences were identified in Paget's bone tissue, predominantly in osteoclasts, using specific hybridization. However, these last results are conflicting because some reports failed to reproduce hybridization with Paramyxovirus. Nevertheless, Paramyxovirus could be responsible for the cytopathologic aspect of multinucleated osteoclasts for the stimulation of hyperexpression, in Paget's disease, of interleukin 6 and of c-fos oncogene known to enhance osteoclastic resorption activity.

Humans↗
PubMed1996

Altered trabecular architecture induced by corticosteroids: a bone histomorphometric study.

Prolonged corticosteroid (CS) therapy induces osteoporosis and fractures. Osteoporosis is characterized at the histomorphometric level by reduced bone volume (BV/TV) and disruption of the three-dimensional (3D) trabecular architecture. Several stereological methods have been proposed to characterize these alterations: measurements of trabecular thickness and trabecular number, star volumes, interconnectivity index (ICI) of the bone marrow spaces, and trabecular bone pattern factor (TBP(f)). These methods were computerized with a single program running on an image analyzer to evaluate the bone changes in a series of iliac biopsies performed on 31 male patients. All of them were asthmatic and had received CS for a long period of time. BV/TV was reduced when compared with age-matched controls. In the CS-treated population, exponential relationships were obtained between bone volume and the different connectivity parameters. The various methods used to measure connectivity were well correlated. When the population was divided into two groups (BV/TV greater or less than an 11% threshold), the architectural disturbances were found to imply two mechanisms. A progressive decline in trabecular thickness was noted in both groups versus controls. Trabecular perforations were not established in the group with BV/TV> 11% with the star volume or ICI, although some alterations were detected by trabecular bone pattern factor measurement. However, perforations were revealed in the group with BV/TV < 11% by all the different methods. Perforations seemed to occur when the trabecular thickness was below 70 mu m. This strongly suggests that bone histomorphometry should take into consideration bone volume in combination with detailed 3D descriptors of the trabecular architecture. Several histological methods need to be used in combination to appreciate the 3D architecture of trabecular bone.

Adrenal Cortex Hormones↗
PubMed1996

Spontaneous multiple vertebral fractures revealed primary haemochromatosis.

The association of haemochromatosis and bone disease is well established, but osteoporotic fracture is an unusual presentation of the disease. We describe a male patient with osteoporotic fractures as a presenting feature of haemochromatosis. The bone histomorphometry showed a dramatic decrease in trabecular bone volume associated with a decrease in cortical bone thickness. Osteoblastic and osteoclastic activities were reduced without any sign of osteomalacia. Staining for iron with Perl's stain showed focal localization at the interface between mineralized trabecular bone and bone marrow. This observation leads us to review the possible mechanisms of osteoporosis.

Hemochromatosis↗
PubMed1995

Effects of tiludronate on bone loss in paraplegic patients.

Immobilization secondary to spinal cord injury is associated with a marked and rapid atrophy of trabecular bone (disuse osteoporosis). This is due to an early increase of osteoclastic bone resorption associated with a pronounced decreased osteoblastic bone formation. Bisphosphonates are antiosteoclastic compounds and they have been effective in preventing disuse osteoporosis. However, some of them also depress osteoblastic activity and may impair the mineralization process. Tiludronate was shown effective in reducing bone resorption in several metabolic bone diseases without inducing mineralization defects. Twenty paraplegic patients (6 females and 14 males) were randomly assigned to three groups: 6 patients entered the placebo group; 7 patients received tiludronate 200 mg/day; and 7 received 400 mg/day. Histomorphometric analysis was performed on transiliac bone biopsies before and after 3 months treatment. An insignificant decrease of bone volume was observed in the placebo group and the 200 mg group. In patients receiving 400 mg/day, a slight increase was noted. Osteoid parameters changed nonsignificantly in three groups although the 400 mg group exhibited a slight tendency to decrease osteoid volume and thickness. Eroded surfaces increased in all groups. The number of osteoclasts (identified histochemically by TRAP staining) increased in the placebo group but decreased in groups receiving tiludronate. Tiludronate appears effective in reducing bone resorption without impairing bone formation in a manner that preserved bone mass and bone cell coupling.

Adolescent↗
PubMed1995

Direct effect of calcitriol on the regulation of parathyroid hormone secretion in a case of pseudo-hypoparathyroidism (a 24-month follow-up study).

The diagnosis of pseudohypoparathyroidism with osteitis fibrosa was made in a 51-year-old woman on the basis of hypocalcaemia, elevated plasma PTH (1-84) and blunted cAMP response to hPTH infusion. Radiologically, widespread signs of hyperparathyroidism were observed and quantitative histomorphometry confirmed the increased bone cellular turnover. Treatment with calcitriol (1,25 dihydroxyvitamin D3) induced a dramatic improvement of bone lesions. During treatment PTH (1-84) normalized with high dosage of calcitriol in spite of low or subnormal levels of serum calcium, and subsequently increased for each reduction of calcitriol dosage despite normal calcium levels. Our observations support a major and direct effect of 1,25 dihydroxyvitamin D3 on the regulation of parathyroid secretion of parathyroids glands.

Biopsy↗
PubMed1995

[Breast micro-opacities of lead origin mimicking microcalcifications].

After a surgical excision of focal mammary "microcalcification" we noticed that in fact they represented fine lead deposits (mean diameter: 100 microns) resulting from an attempted suicide (22 long rifle) 10 years previously. The leaded nature of these foreign microbodies was demonstrated by a micro-analysis by energy dispersion on histological slides.

Breast↗
PubMed1994

Bone histomorphometry in 50 normal Tunisian subjects.

Quantitative bone histomorphometry was done on undecalcified sections of iliac crest bone specimens obtained at autopsy from 50 normal subjects (24 males and 26 females). The following parameters were measured: cortical thickness (Ct.Th), trabecular bone volume (BV/TV), trabecular number (Tb.N), trabecular thickness (Tb.Th), osteoid volume (OV/BV), osteoid surfaces (OS/BS), osteoid thickness (O.Th) and eroded surfaces (ES/BS). There was a significant age-related decrease in BV/TV in both sexes which followed a x3 polynomial regression. A significant decrease of Tb.Th was noted in males after the fifth decade. In males, bone loss was 1.5% per decade, but in females it was 0.36% before menopausal period and 2% after. Other parameters were unrelated to age and sex.

Adolescent↗