[Development of a methodological guide on the implementation of a pharmaceutical decision support system: Feedback from a French university hospital]. / Élaboration d'un guide méthodologique sur l'implantation d'un système d'aide à la décision pharmaceutique : retour d'expérience d'un centre hospitalier universitaire français.

OBJECTIVE: Develop a methodological guide on the implementation of a PDSS (pharmaceutical decision support system). METHOD: Observational study, retrospective conducted at Lille University Hospital from May 2017 to December 2020, corresponding to the period of implementation and then use of the software. The different phases of the project are described as well as the methodology at each stage. RESULTS: Four stages seem necessary for the establishment of the PDSS: reflection and preparation of the project, contracting, implementation, use and evaluation. Based on these results and our experience, in particular the difficulties encountered, a methodological diagram of the various steps necessary for the implementation of a PDSS is proposed. CONCLUSION: The establishment of a PDSS, especially in the field of clinical pharmacy, is a long multidisciplinary process. Several steps, from project preparation to production start-up are necessary. Planning the different stages is essential for the proper implementation of the SADP so that the installation is as efficient as possible.

[Selection and optimal sequence of critical elements for medication review: A simulation with hospital pharmacy residents]. / Sélection et séquence optimale des éléments critiques de validation des ordonnances : une simulation avec des résidents en pharmacie hospitalière.

OBJECTIVES: The main objective of this study was to compare the responses of pharmacy residents regarding critical steps for medication order review, in the presence or absence of clinical pharmacists on patient care units, to describe the sequence of these steps and to compare them to an optimal sequence. The secondary objectives were to test this sequence in a simulation and to assess the residents' level of agreement on medication order review. METHODS: Twenty-two validation steps were selected from guidelines. A simulation on order review was organized in three steps: selecting elements judged to be necessary or not for the order review critical path, then organizing this sequence in chronological order, implementation of this critical path on two simulated practical cases, resident perceptions about order review in their training. RESULTS: Forty-one residents participated in the activity. Responses were heterogeneous regarding the elements' sequence and the time required for the review of a simulated case (3-13minutes). A majority of residents considered that their training was insufficient (29/41), that pharmacists validated differently (27/41), and that it was impossible to review the 22 proposed items for each prescription (30/41). CONCLUSIONS: This article highlights heterogeneous medication order review practices among pharmacy residents, due to a lack of training in their curriculum according to them. It is essential to acquire medication order review standard both locally and nationally.

Transverse approach between tunnel environment and corrosion: particulate matter in the Grand Mare tunnel.

A tunnel-type semi-enclosed atmosphere is characterized by a higher particulate pollution than urban zones and highlights the particulate species having an impact on material degradation. Therefore, a transverse approach between air composition and its consequences upon longevity of materials is necessary, requiring a better knowledge of tunnel atmosphere and a better understanding of material degradation inside a tunnel for operating administration. The characterization of particulate matter collected inside a road tunnel in Rouen (France) allows us to set up the features of the particle characteristics of the real conditions of field exposure. Two sampling campaigns include analyses of organic and water-soluble ionic fractions. The current work shows that organic species, grouped into two sets derived primarily from engine exhaust and debris with wear particles resuspended by the traffic, are divided into two groups: a majority comprising n-alkanes, alkanoic acids, phthalates, ketones, and benzothiazole and a minority one composed of BTEX (benzene, toluene, ethylbenzene, and xylenes), polycyclic aromatic hydrocarbons (PAHs), fatty acid methyl esters (FAMEs), furans, phenols, and alkenes. As regards the water-soluble ionic fraction, the ionic species such as Cl(-), SO4(2-), CH3COO(-), HCOO(-), NO3(-), NH4+, and Na+ are involved in the degradation process. The inorganic particles (insoluble and slightly soluble), debris and wear particles, organic acids, and relative humidity play a key role and are important factors to consider in the degradation process.

The relationship between anti-idursulfase antibody status and safety and efficacy outcomes in attenuated mucopolysaccharidosis II patients aged 5 years and older treated with intravenous idursulfase.

In the pivotal phase II/III trial of idursulfase administered intravenously to treat mucopolysaccharidosis II, approximately half of the patients developed antibodies to idursulfase. This post-hoc analysis of data from the phase II/III trial and extension study examined the relationship between antibody status and outcomes. A total of 63 treatment-naïve patients received 0.5 mg/kg of intravenous idursulfase weekly for two years. Thirty-two patients (51%) were positive for anti-idursulfase IgG antibodies, 23 of whom (37%) became persistently positive. All patients who developed an antibody response did so by their scheduled Week 27 study visit. Positive antibody status appeared to have no statistically significant effect upon changes in six-minute walk test distance, percent predicted forced vital capacity, or liver and spleen volume. All patients showed significant decreases in urinary GAG levels, although the antibody positive group maintained somewhat higher urinary GAG levels than their antibody-negative counterparts at the end of study (138.7 vs. 94.7 µg/mg creatinine, p = 0.001). Antibody positivity was not associated with a higher event rate for serious adverse events. Among patients who had no prior infusion-related reactions, antibody positive patients were 2.3 times more likely to have a first infusion-related reaction than those who would remain negative (p = 0.017); the risk increased to 2.5 times more likely for those who were persistently positive (p = 0.009). These differences in risk disappeared among patients with a previous infusion-related reaction, likely because of preventive measures. A genotype analysis for the 36 patients with available data found that patients with nonsense or frameshift mutations may be more likely to develop antibodies, to experience infusion-related reactions, and to have a reduced uGAG response than those with missense mutations, suggesting the possibility that antibodies are not a driver of clinical outcomes but rather a marker for genotype.

Inhaled mRNA therapy for treatment of cystic fibrosis: Interim results of a randomized, double-blind, placebo-controlled phase 1/2 clinical study.

BACKGROUND: MRT5005, a codon-optimized CFTR mRNA, delivered by aerosol in lipid nanoparticles, was designed as a genotype-agnostic treatment for CF lung disease. METHODS: This was a randomized, double-blind, placebo-controlled Phase 1/2 study performed in the US. Adults with 2 severe class I and/or II CFTR mutations and baseline ppFEV1 values between 50 and 90% were randomized 3:1 (MRT5005: placebo). Six dose levels of MRT5005 (4, 8, 12, 16, 20, and 24 mg) or placebo (0.9% Sodium Chloride) were administered by nebulization. The single ascending dose cohort was treated over a range from 8 to 24 mg; the multiple ascending dose cohort received five weekly doses (range 8-20 mg); and the daily dosing cohort received five daily doses (4 mg). RESULTS: A total of 42 subjects were assigned to MRT5005 [31] or placebo [11]. A total of 14 febrile reactions were observed in 10 MRT5005-treated participants, which were mild [3] or moderate [11] in severity; two subjects discontinued related to these events. Additionally, two MRT5005-treated patients experienced hypersensitivity reactions, which were managed conservatively. The most common treatment emergent adverse events were cough and headache. No consistent effects on FEV1 were noted. CONCLUSIONS: MRT5005 was generally safe and well tolerated through 28 days of follow-up after the last dose, though febrile and hypersensitivity reactions were noted. The majority of these reactions resolved within 1-2 days with supportive care allowing continued treatment with MRT5005 and careful monitoring. In this small first-in-human study, FEV1 remained stable after treatment, but no beneficial effects on FEV1 were observed.

Transverse approach between real world concentrations of SO2, NO2, BTEX, aldehyde emissions and corrosion in the Grand Mare tunnel.

With regard to automotive traffic, a tunnel-type semi enclosed atmosphere is characterized by a higher concentration of gaseous pollutants than on urban traffic roads and highlights the gaseous effluent species having an impact on material degradation. Therefore, a transverse approach between air quality and its consequences upon the longevity of materials is necessary, implying better knowledge of tunnel atmosphere and a better understanding of material degradation inside a tunnel for operating administration. Gaseous pollutant measurements carried out in a road tunnel in Rouen (Normandy) give the real world traffic concentrations of experimental exposure conditions. The sampling campaigns, achieved in summer and winter include SO2, NO2, BTEX and aldehyde analyses. Effluent profiles in the upward and downward tubes have been established. The current work shows that SO2, NO2, formaldehyde, acetaldehyde, propanal and butanal must be considered in the degradation process of materials in a stuffy environment. As regards NO2, its concentration depends on the modification of the automotive fleet. The total aldehyde concentrations indicate no particular trend between the two bores. Formaldehyde, acetaldehyde, propanal, butanal and acrolein species are the most abundant species emitted by vehicles and represent 90% to 95% of the total aldehyde emissions.

Implementation of less-invasive surfactant administration in a Canadian neonatal intensive care unit.

BACKGROUND: Less-invasive surfactant administration (LISA) is a recent technique used extensively in Europe but rarely used in North America. The aim of this study was to describe our experience following LISA implementation using poractant in a Canadian neonatal intensive care (NICU). METHODS: A retrospective analysis was conducted from June 2017 to April 2021 of LISA procedures in preterm infants. Data were collected on patient characteristics, outcomes following LISA, laryngoscopy, and adverse events. The primary outcome was the rate of successful LISA procedures. SETTING: Level IIIa academic NICU. RESULTS: LISA was successful in 93 of 101 infants (92%). Median gestational age was 30.9 weeks (interquartile range [IQR]: 29.4-33.0). All infants received atropine and fentanyl premedication. Eight LISA procedures were unsuccessful: five because of thoracic rigidity and three because of inability to expose the vocal cords. In the 93 successful procedures, a second dose of surfactant was needed for 15 of 93 infants (16.1%), either by repeated LISA (7/15; 7.5%) or by endotracheal intubation (8/15; 8.6%). In 63.4% of successful procedures, one laryngoscopy attempt was made. The median duration of laryngoscopy attempts was 60 s (IQR: 52-110). Two types of catheters were used: the multi-access catheter (MAC) or the Angiocath in 67% and 33% of procedures, respectively. One infant had bradycardia and 30.6% had profound desaturation of <75%. CONCLUSION: LISA with poractant alfa was implemented in a Canadian NICU with a high degree of procedural success. Fentanyl may lead to more adverse events with a risk of interrupting LISA and may not be the ideal agent for this procedure. These results may encourage wider dissemination of LISA in North America.

Beyond the magnetic domain matching in magnetic exchange coupling.

We report a new macroscopic first-field-induced magnetic anisotropy for Co/α-Fe2O3(0001) layers, a prototypical ferromagnetic-antiferromagnetic interface for which the antiferromagnetic film has small in-plane magnetic anisotropy as compared to the interface coupling. We demonstrate that the effect is due to a first-field-induced irreversible magnetic domain motion in the antiferromagnetic layer, dragged by the ferromagnetic Co one. Whereas the initial domain matching is lost, the macroscopic manifestations of the exchange coupling remain stable. Therefore, the initial domain matching probably has only a marginal role in the explanation of the magnetic exchange coupling.

[Interferences by a monoclonal IgM in biochemical analyses: detection and recommendations]. / Interférences par une IgM monoclonale dans un bilan biochimique : détection et recommandations.

We present a case of analytical interference on three parameters (lactate dehydrogenase, uric acid and alkalin phosphatase), caused by a monoclonal IgM, evidenced in a patient with Waldenström disease. Mechanism of interference was probably related to the formation of complexes between paraprotein and lithium heparin, which result in precipitation during clinical chemistry assays, inducing a bias in the results. Management recommendations in case of suspicion of interference in clinical chemistry analysis are detailed. Are discussed for the case report, clinical consequences, possible mechanisms and evolution of interference under treatment, according to the concentration of the monoclonal protein.

[Is primiparity, the only risk factor for type 3 and 4 perineal injury, during delivery?]. / La primiparité est-elle le seul facteur de risque des lésions du sphincter anal en cours d'accouchement?

OBJECTIVE: Primiparity has been identified as the main risk factor of type 3 and 4 perineal injuries The purpose of our study, according to a population-based observational study, was to identify other clinical risk factors for lesions during vaginal delivery. PATIENTS AND METHODS: Two groups have been compared. Group A or study group (n=63) was defined as parturients with three or four-degree perineal tears. Group B or control group (n=67) included women who delivered vaginally without any perineal lesion during the same period. Characteristics of the population were compared: maternal age, race, maternal weight, BMI (Body Mass Index), parity, mode of anaesthesia, gestational age, post maturity, length of labor, fetal weight, mode of delivery (assisted or not). Specific characteristics were also compared, obesity, shoulder dystocia, type of presentation, episiotomy and dose of ocytocin. RESULTS: Primiparity was significantly associated with higher frequency of sphincter lacerations (71 vs 43%, p=0.001). The patients of group A were with significantly higher weight than the patients of control group (67 vs 63 kg, p=0.036). Futhermore the BMI was different in the two groups (25,6 vs 23,4, p=0.003). There was a significant difference according to the length of the second part of labor (68 vs 48 min, p=0.037) and the posterior variety (32 vs 4%, p<0.001). The occurrence of shoulder dystocia was only just significant (6 vs 0%, p=0.052). Assisted-extraction is highly associated with perineal injuries (44 vs 1%, p<0.001). Futhermore the instrument has been concerned by the difference: Tarnier's forceps-assisted extraction (14 vs 1%, p=0.003), Suzor's forceps-assisted extraction (16 vs 0%, p=0.0005), Thierry's spatula-assisted extraction (14 vs 0%, p=0,0005). The association forceps and episiotomy has been found with higher frequency of perineal injury (43 vs 1%, p<0,0001). There were no difference between the 2 groups according fetal characteristics, type of analgesia, maternal age, gestational age, post-maturity or dose of ocytocin. DISCUSSION AND CONCLUSION: Primiparity is not the only risk factor of perineal injuries. Other risk factors have been found: assisted-extraction, occiput posterior fetal head position, and association episiotomy and assisted-extraction. Black origin seems to be protective.

Predicted coreceptor usage at end-stage HIV disease in tissues derived from subjects on antiretroviral therapy with an undetectable plasma viral load.

HIV cure research is increasingly focused on anatomical tissues as sites for residual HIV replication during combined antiretroviral therapy (cART). Tissue-based HIV could contribute to low-level immune activation and viral rebound over the course of infection and could also influence the development of diseases, such as atherosclerosis, neurological disorders and cancers. cART-treated subjects have a decreased and irregular presence of HIV among tissues, which has resulted in a paucity of actual evidence concerning how or if HIV persists, replicates and evolves in various anatomical sites during therapy. In this study, we pooled 1806 HIV envelope V3 loop sequences from twenty-six tissue types (seventy-one total tissues) of six pre-cART subjects, four subjects with an unknown cART history who died with profound AIDS, and five subjects who died while on cART with an undetectable plasma viral load. A computational approach was used to assess sequences for their ability to utilize specific cellular coreceptors (R5, R5 and X4, or X4). We found that autopsied tissues obtained from virally suppressed cART+ subjects harbored both integrated and expressed viruses with similar coreceptor usage profiles to subjects with no or ineffective cART therapy (i.e., significant plasma viral load at death). The study suggests that tissue microenvironments provide a sanctuary for the continued evolution of HIV despite cART.

Glycation of apolipoprotein E impairs its binding to heparin: identification of the major glycation site.

The increased glycation of plasma apolipoproteins represents a possible major factor for lipid disturbances and accelerated atherogenesis in diabetic patients. The glycation of apolipoprotein E (apoE), a key lipid-transport protein in plasma, was studied both in vivo and in vitro. ApoE was shown to be glycated in plasma very low density lipoproteins of both normal subjects and hyperglycemic, diabetic patients. However, diabetic patients with hyperglycemia showed a 2-3-fold increased level of apoE glycation. ApoE from diabetic plasma showed decreased binding to heparin compared to normal plasma apoE. The rate of Amadori product formation in apoE in vitro was similar to that for albumin and apolipoproteins A-I and A-II. The glycation of apoE in vitro significantly decreased its ability to bind to heparin, a critical process in the sequestration and uptake of apoE-containing lipoproteins by cells. Diethylenetriaminepentaacetic acid, a transition metal chelator, had no effect on the loss of apoE heparin-binding activity, suggesting that glycation rather than glycoxidation is responsible for this effect. In contrast, glycation had no effect on the interaction of apoE with amyloid beta-peptide. ApoE glycation was demonstrated to be isoform-specific. ApoE(2) showed a higher glycation rate and the following order was observed: apoE(2)>apoE(4)>apoE(3). The major glycated site of apoE was found to be Lys-75. These findings suggest that apoE is glycated in an isoform-specific manner and that the glycation, in turn, significantly decreases apoE heparin-binding activity. We propose that apoE glycation impairs lipoprotein-cell interactions, which are mediated via heparan sulfate proteoglycans and may result in the enhancement of lipid abnormalities in hyperglycemic, diabetic patients.

The bisphosphonate tiludronate is a potent inhibitor of the osteoclast vacuolar H(+)-ATPase.

Although bisphosphonates have been shown to be potent inhibitors of osteoclast-mediated bone resorption in vivo and in vitro and are used as therapeutic agents in hyper-resorptive bone diseases such as Paget disease or hypercalcemia of malignancy, their exact biochemical target(s) and mode(s) of action are for the most part still unknown. The resorption of bone requires solubilization of the mineral component of the matrix, achieved by acidification of the resorbing compartment by a vacuolar-type proton ATPase (V-ATPase) present in the ruffled border membrane of osteoclasts. Since we have shown that the V-ATPase is inhibited by both ADP and phosphate, which share structural characteristics with bisphosphonates, we hypothesized that inhibition of the osteoclast V-ATPase could be one of the mechanism(s) by which bisphosphonates inhibit bone resorption. Pyrophosphate and the bisphosphonates etidronate, alendronate, and YM-175 inhibited proton transport in membrane vesicles derived from chicken kidney and osteoclasts but with very low potency (IC50 > or = 5 mM). In contrast, the ability of tiludronate to inhibit proton transport was 5-fold higher in kidney-derived vesicles (IC50 = 1.1 mM) and 10,000-fold higher in vesicles derived from osteoclasts (IC50 = 466 nM). Tiludronate also potently inhibited proton transport in yeast microsomal preparations (IC50 = 3.5 microM) and inhibited the activity of purified yeast V-ATPase. The inhibition of the osteoclast V-ATPase-mediated proton transport by tiludronate was rapid, pH-dependent, and reversible. No change in membrane vesicle permeability to protons was detected. The inhibition was noncompetitive with respect to ATP, and tiludronate did not protect the pump from inactivation by N-ethylmaleimide, strongly suggesting that tiludronate does not bind to the catalytic site of the enzyme. It is concluded that tiludronate is a significantly more potent inhibitor of V-ATPase than other bisphosphonates and that it has a significant degree of selectivity for the avian osteoclast V-ATPase relative to the avian kidney V-ATPase.

Effects of tiludronate on bone mass, structure, and turnover at the epiphyseal, primary, and secondary spongiosa in the proximal tibia of growing rats after sciatic neurectomy.

To evaluate the effects of tiludronate on the mass, structure, and turnover of cancellous bone regions in immobilized rat tibiae, we performed a 4 week dosing experiment. The right hindlimbs of 84 Sprague-Dawley rats (5 weeks old) wee neurectomized or sham operated. Animals were assigned to seven groups (n = 12 each); group 1 was sham operated, and groups 2-7 were neurectomized. Groups 1 and 2 were given vehicle only (distilled water), and groups 3, 4, and 5 were given tiludronate orally at doses of 25, 50, and 100 mg/kg body weight (BW)/day, respectively, throughout the experimental period. Group 6 was given 100 mg/kg BW/day of the agent for the first 2 weeks only, and group 7 received vehicle only for the first 2 weeks and then 100 mg/kg BW/day of the agent for the last 2 weeks. After tetracycline labeling was performed, the right tibiae were removed from the animals and processed to yield undecalcified sections. Histomorphometry was performed in the epiphyseal, primary, and secondary spongiosa of the proximal tibia. In group 2, trabecular bone volume (BV/TV) and trabecular number (Tb.N) were significantly decreased in the primary and secondary spongiosae, but this did not occur in the epiphyseal spongiosa. Osteoid surface (OS/BS) was decreased and osteoclast surface (Oc.S/BS) was increased in the secondary spongiosa. Tiludronate increased BV/TV and Tb.N in the primary spongiosa by reducing the values for the parameters of osteoclast surface (Oc.S/BS) and osteoclast number (Oc.N/BS). Osteoid surface in this region was not decreased by the agent. In groups 4 and 5, tiludronate prevented bone loss in the secondary spongiosa by reducing both OS/BS and Oc.S/BS. In group 6, BV/TV in the primary spongiosa was maintained at the level of group 1, but Oc.S/BS and Oc.N/BS were elevated. In the secondary spongiosa, bone mass was preserved and the reduction in these parameters was maintained. In group 7, however, BV/TV was increased in the primary spongiosa as a result of a reduction in osteoclastic resorption; in the secondary spongiosa, however, BV/TV was decreased and trabecular turnover was not reduced at the end of the experiment in these growing animals. Mineral apposition rates were not reduced by tiludronate. This study clearly demonstrated that this agent prevented immobilization bone loss by inhibiting resorption.(ABSTRACT TRUNCATED AT 400 WORDS)

Longitudinal effect of tiludronate on bone mineral density, resonant frequency, and strength in monkeys.

The effect of Tiludronate on bone was studied in 72 growing monkeys (Papio papio), 36 males and 36 females, aged 4-7 years. They were randomly allocated into four groups (18 animals per group, 9 males and 9 females): group I, controls; group II, 10 mg/kg/day; group III, 20 mg/kg/day; and group IV, 40 mg/kg/day of Tiludronate. A total of 12 animals (6 males and 6 females) in each group were sacrificed at the end of treatment (1 year) and 6 animals (3 males and 3 females) per group 1 year later. Bone mineral density (BMD) was measured by dual-photon absorptiometry. Biomechanical properties were evaluated by an impact torsion test and by resonant frequency analysis. Bone mineral measurements indicated that at the end of 1 year of treatment BMD was significantly higher, especially at the distal epiphysis of the radius, than in controls. No significant differences between groups were found in BMD 1 year after stopping treatment. Biomechanical analyses indicated that torsional stiffness increased after treatment. No differences between groups were found 1 year after stopping treatment. Results of resonant frequencies indicated an increased calculated transversal stiffness after treatment and 1 year later and an increased buckling strength 1 year after stopping treatment. In conclusion, the results on the effect of Tiludronate in growing monkeys indicate a profound effect of this drug on bone density and biomechanical properties. The biomechanical results indicate that this drug is safe, with conservation of bone strength despite a change in intrinsic mechanical properties of the bone.

Recovery of monkey brain after prolonged ischemia. II. Protein synthesis and morphological alterations.

Recovery of protein synthesis following 1 h of complete ischemia of the monkey brain was assessed by 3H-labeled amino acid incorporation in vivo at various postischemic periods between 1.5 and 24 h. The regional autoradiographic patterns obtained were compared on the basis of precursor-product relationships determined biochemically at the end of the tracer incorporation studies. Shortly after ischemia, protein synthesis was severely inhibited, but it gradually recovered with increasing recirculation times. In the cerebellum it returned to almost normal levels within 3 h and in the cortex within 24 h. Hippocampal and thalamic regions, however, did not recover control levels of protein synthesis at 24 h. Histoautoradiographic evaluation of amino acid incorporation in individual neurons revealed recovery of pyramidal neurons in the CA1 and CA3 sectors of the hippocampus within 6 h of recirculation, which, however, was followed by secondary inhibition after longer recirculation. Neurons in cortical layer 5 steadily recovered to near control within 24 h, with the exception of those located in arterial border zones, which returned to only 50% of control at 24 h. Incomplete recovery was also observed in thalamic neurons and Purkinje cells. The regional and histoautoradiographic pattern of protein synthesis correlated with the morphological appearance of cells. Ischemic cell changes (mainly of the dark type with microvacuolization and perineuronal glial swelling) were marked after short recirculation times but gradually disappeared in parallel with the return of protein synthesis in most regions of the brain. Only in pyramidal cells of the hippocampus, thalamic neurons, and Purkinje cells were changes not reversed during the observation period. The results obtained corroborate the electrophysiological observations reported in the first part of this investigation and support the notion that the majority of the neurons of monkey brain survive complete cerebrocirculatory arrest of 1 h for at least 1 day.

Tiludronate: bone pharmacology and safety.

The pharmacological properties of tiludronate (4-chlorophenyl)thiomethylene bisphosphonate), a sulfured bisphosphonate, have been characterized in a series of preclinical in vivo and in vitro studies. In vivo, tiludronate exerts a dose-dependent inhibitory activity on bone resorption. This property was demonstrated in several animal models, including rats, ewes, and dogs, when bone resorption was induced by administration of retinoid acid or parathyroid hormone, or by immobilization, ovariectomy or orchidectomy. By uncoupling bone resorption from bone formation, tiludronate can induce a positive calcium and phosphate balance. When administered either continuously or intermittently to ovariectomized osteoporotic rats, tiludronate promotes a significant increase in bone mass. This positive effect is associated with an increase in mechanical resistance. Bone tolerance studies indicate that tiludronate is a safe compound with an appreciable therapeutic margin since it can effectively inhibit bone resorption without reducing bone mineralization and strength. In vitro, tiludronate added to bone tissue culture inhibits calcium release, lysosomal enzyme secretion and collagen matrix degradation when induced by various stimulators of bone resorption. At the cellular level, tiludronate does not appear to exert its inhibitory effect on bone resorption by impairing either the recruitment, the migration or the fusion of osteoclast precursors. Tiludronate could act on mature osteoclasts by reducing their capacity to secrete proton into the resorption space and also by favoring their detachment from the bone matrix. The available preclinical data indicate that tiludronate should be an efficacious bisphosphonate in the management of clinical conditions characterized by excessive bone resorption.

Characterization of the trabecular rat bone mineral: effect of ovariectomy and bisphosphonate treatment.

Bisphosphonates, potent inhibitors of bone resorption, have been used clinically to correct the continued loss of bone mass in osteoporosis and in other conditions. However, there has been some concern that long-term treatment with these compounds, as well as more recently developed drugs, may also decrease the rate of bone formation. Bisphosphonates, which are strongly bound to hydroxyapatite crystals, may alter the structure and reactivity of the crystals, interfere with new crystal nucleation and growth, as well as alter the short-range order of newly formed crystals. We have investigated the chemistry and structure of the solid calcium-phosphate mineral phase of lumbar vertebrae of ovariectomized, 6.5-month-old rats treated with bisphosphonates for 1 year after onset of osteopenia. Appropriate control groups were used for comparison. The techniques used to assess the mineral phase were chemical analyses, Fourier transform-infrared (FT-IR) and FT-Raman spectroscopy, FT-IR microspectroscopy, and phosphorus-31 magic-angle-sample spinning nuclear magnetic resonance spectroscopy ((31)P MAS NMR). The (31)P MAS NMR spectra of trabecular bone of lumbar vertebrae of control, ovariectomized, and treated animals were similar. However, there were several significant differences in the results obtained by FT-IR spectroscopy of the whole tissue samples, FT-IR microspectroscopy of sections of bone, and chemical analyses. For example, whereas chemical analyses demonstrated that the CO(3) content of the mineral phase of the ovariectomized animals was decreased compared with controls, FT-IR microspectroscopy of bone sections showed no changes in the relative CO(3) content, but some changes in the environment of the CO(3) groups. However, chemical analyses of the crystals, combined with data from all three spectroscopic methods and with data from serum analysis, did indicate small changes in the mineral phase after ovariectomy, corrected after treatment with bisphosphonates. In any event, the chemical and structural data in the present studies demonstrate that the bisphosphonate, tiludronate, does not significantly alter the mineral components of bone after 1 year of treatment during the course of which bone loss was reversed.

Bisphosphonate tiludronate increases bone strength by improving mass and structure in established osteopenia after ovariectomy in rats.

We examined the mechanical properties of bone in ovariectomized rats treated with tiludronate. 186 Sprague-Dawley (SD) rats, 6 months of age, were assigned to 13 groups and were maintained for 3-9 months after surgery. Ovariectomy (ovx) groups were given tiludronate orally at the respective doses of 0 (vehicle), 12.5 (low), 25 (medium), and 50 (high) mg/kg body weight daily for 3 months beginning 3 months after surgery. Rats were killed at 0 (start), 3, 6, and 9 months. Whereas bone mineral density (BMD) values of the midfemur did not increase after ovx, the values in the sham-operated groups increased age-dependently. Bending moment to failure of the femur in the sham group was larger than that of the ovx control group at 9 months. In the ovx control groups, the ultimate compressive load values of the third lumbar body were reduced compared with those in the sham groups at 3 months and thereafter. Although serum osteocalcin levels were decreased in the medium- and high-dose tiludronate groups, both serum PTH and 1,25(OH)2D levels were increased only in the high-dose group. Femoral BMD, mechanical properties, and the cortical bone area were increased by the high dose at 9 months. Lumbar ultimate compressive load and the circumscribing cortical shell area in the high-dose group were increased at 6 months and thereafter. The trabecular number values were maintained at 6 and 9 months by the high dose. These data demonstrate that tiludronate administration increased the mechanical properties of bone by preserving the age-dependent increases in the cortical bone mass and three-dimensional structure of trabecular bone. These effects seemed to be due to reduced bone turnover by the agent.

A possible mechanism of the specific action of bisphosphonates on osteoclasts: tiludronate preferentially affects polarized osteoclasts having ruffled borders.

The mechanism of action of tiludronate [(4-chlorophenyl)-thiomethylene bisphosphonate] on osteoclastic bone resorption was examined in mouse culture systems. Tiludronate did not inhibit the formation of osteoclast-like multinucleated cells (OCLs) induced by 1 alpha,25-dihydroxyvitamin D3 in cocultures of mouse osteoblastic cells and bone marrow cells. OCLs obtained from cocultures on collagen gel-coated dishes, treated with tiludronate, formed as many resorption pits on dentine slices as those obtained from the control cocultures. However, pit formation by OCLs was dose-dependently inhibited when tiludronate was added directly to the pit formation assay. Other bisphosphonates such as alendronate and etidronate dose-dependently inhibited pit formation according to the in vivo potencies of the respective bisphosphonates to inhibit bone resorption. However, they had no inhibitory effect on the recruitment of OCLs induced by 1 alpha,25-dihydroxyvitamin D3 in the cocultures. When OCLs were placed on dentine slices, they formed the ringed structure of F-actin-containing podosomes and ruffled borders (polarized OCLs) even in the presence of tiludronate. However, the actin rings in OCLs were disrupted by the addition of tiludronate soon after they began to resorb dentine. In contrast, OCLs placed on collagen gel formed neither actin rings nor ruffled borders (nonpolarized OCLs), and showed no response to tiludronate. OCLs formed from the spleen cells of osteosclerotic (oc/oc) mice developed the ringed structure of podosomes, but not ruffled borders, on dentine slices. The actin ring in the oc/oc spleen cell-derived OCLs placed on dentine slices was not disrupted by the addition of tiludronate.(ABSTRACT TRUNCATED AT 250 WORDS)