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1.
Detection of the center of the hip joint in computer-assisted surgery: an evaluation study of the Surgetics algorithm. 总被引:4,自引:0,他引:4
Eric Stindel Daniel Gil Jean-Louis Briard Philippe Merloz Frédéric Dubrana Christian Lefevre 《Computer aided surgery》2005,10(3):133-139
OBJECTIVE: The aim of this paper is to assess the accuracy of an algorithm implemented by PRAXIM in the SURGETICS navigation station for detection of the hip center. This study will assess the robustness and accuracy of the algorithm in various clinical situations such as those involving non-sphericity of the femoral head, motion of the pelvis during hip center detection, and restricted range of motion. MATERIALS AND METHODS: The localization of the hip center, based on kinematics, relies on the recording of n successive positions of the femoral rigid body in the localizer reference system during a passive circumduction motion of the hip joint. Therefore, the shape of the clouds of points acquired may vary from one acquisition to the next. To allow a comprehensive study of the consequences of these variations for hip center detection, we developed a simulator to generate numerous clouds of points. Results given subsequently for each test are the values of the difference between the femoral mechanical axis computed with C(c), the computed hip center, and the same axis computed with C(o), the reference hip center. RESULTS: Test 1: Sensitivity to noise. The errors ranged from 3.33 E - 12 (SD 3.29E - 12) for a noise of 0 mm to 8.18E - 1 (SD - 7.05E - 1) for a noise of 15 mm. Test 2: Sensitivity to the shape of the acquisition motion. All trajectories gave an error < 1 degrees . Test 3: Sensitivity to restricted range of motion. No value > 1 degrees was found during this test. Test 4: Sensitivity to the distance between two points of the cloud. No value > 0.5 degrees was found during this test. Test 5: Sensitivity to the number of points included in the cloud. No value > 1 degrees was found during this test. CONCLUSIONS: The Surgetics algorithm is robust to noise, can compensate for pelvic motion, and can be used even in the case of restricted range of motion. 相似文献
2.
Jean-Marie Danion Marie-Agathe Zimmermann Dominique Willard-Schroeder Danielle Grangé Marie Welsch Jean-Louis Imbs Léonard Singer 《Psychopharmacology》1990,102(3):422-424
The effects of scopolamine, an anticholinergic drug, of trimipramine, a tricyclic antidepressant with both anticholinergic and sedative properties, of diazepam and a placebo, on explicit memory and repetition priming were assessed using a free-recall task and a word-stem completion task. Forty-eight healthy volunteers took part in this double-blind study. Diazepam provoked a dissociation between free recall, which was profoundly impaired, and word completion, which was spared. No significant changes in memory performances were observed in the scopolamine group; however, a significant correlation between explicit and implicit memory performances was observed in this group. At the low dose used, the effects of trimipramine on memory were mild. The results suggest that the cholinergic system is involved in the priming effect. 相似文献
3.
Claude Linassier Pascale Poumier-Gaschard Jean-Louis Bremond Carole Barin Oliver Haillot Jean Pierre Lamagnere Philippe Colombat 《Cancer chemotherapy and pharmacology》1992,30(3):233-234
Summary Simultaneous tumors are rarely encountered during the course of acute leukemias. We report on a case of seminoma of the testis that occurred during the evolution of acute myelogenous leukemia. To our knowledge, this stimultaneous association has not previously been described, but a causal relationship was not apparent in the present case. The likelihood of a common carcinogenesis existed, but direct exposure to carcinogens could not be established. Although the results of a physical examination and echography were normal at the time of diagnosis, we cannot exclude the presence of microscopic cancer of the testis. Since the dissemination pattern of seminoma is usually slower than that observed in this case and the disease remains limited to the lymph nodes for long periods following dissemination, the rapid development of the present case might have been attributable to the immunosuppression and the scrotal sepsis that occurred during the induction therapy. Immunosuppression might have stimulated the progression of a primary microscopic seminoma and the development of metastasis, whereas the scrotal sepsis and inflammation might have favored the occurrence of metastasis through bypass of the lymphatic barrier. 相似文献
4.
5.
Jean-Louis Schlienger 《Cahiers de Nutrition et de Diététique》2007,42(4):225-228
May garlic have beneficial effects on cardiovascular and metabolic diseases?Some data support that garlic may have benefical medicinal functions on dyslipidemia, hypertension and diabetes mellitus. However the results of clinical trials are controversial. Several metaanalysis and a systematic review didn’t confirm that garlic or its compounds had significant effects on plasma lipids or on blood pressure. The hypoglycaemic effect was supported by any randomised clinical study. Contrary to the assertion of many physicians and patients, consumption of garlic can’t be considered as an alternative treatment for dyslipidemia or hypertension. 相似文献
6.
A significant increase of cutaneous laser Doppler flowmetry was found before blood flow decreases with increasing pressure during a 5 mmHg min−1 increase of pressure strain on the finger. Pre-treatment with a local anaesthetic or chronically applied capsaicin, resulted in the disappearance of the vasodilatory response. These results suggest an original vasodilatory axon reflex response to non-noxious pressure strain which is initiated by capsaicin-sensitive nerve terminals in the human skin. 相似文献
7.
Listeria monocytogenes Stimulates Mucus Exocytosis in Cultured Human Polarized Mucosecreting Intestinal Cells through Action of Listeriolysin O 总被引:4,自引:0,他引:4 下载免费PDF全文
Marie-Hlne Coconnier Elyess Dlissi Myriam Robard Christian L. Laboisse Jean-Louis Gaillard Alain L. Servin 《Infection and immunity》1998,66(8):3673-3681
When the intracellular pathogen Listeria monocytogenes infects cultured human mucosecreting polarized HT29-MTX cells apically, it induces the stimulation of mucus exocytosis without cell entry. Using a set of isogenic mutants and purified listeriolysin O (LLO), we identified the L. monocytogenes thiol-activated exotoxin LLO as the agonist of mucus secretion. We demonstrated that the LLO-induced mucus exocytosis did not result from the LLO membrane-damaging activity. We found that LLO-induced mucus exocytosis is an event requiring the binding of LLO to a brush border-associated receptor and membrane oligomerization of the exotoxin. By a pharmacological approach, we demonstrated that no regulatory system or intracellular transducing signal known to be involved in control of mucin exocytosis was activated by LLO. Based on the present data, the stimulatory action of LLO on mucin exocytosis could be accounted for either by an unknown signaling system which remains to be determined or by direct action of LLO with the membrane vesicle components involved in the intracellular vesicular transport of mucins. 相似文献
8.
The nonstructural protein 3 (NS3) of Dengue virus (DV) is a multifunctional enzyme carrying activities involved in viral RNA replication and capping: helicase, nucleoside 5'-triphosphatase (NTPase), and RNA 5'-triphosphatase (RTPase). Here, a 54-kDa C-terminal domain of NS3 (DeltaNS3) bearing all three activities was expressed as a recombinant protein. Structure-based sequence analysis in comparison with Hepatitis C virus (HCV) helicase indicates the presence of a HCV-helicase-like catalytic core domain in the N-terminal part of DeltaNS3, whereas the C-terminal part seems to be different. In this report, we show that the RTPase activity of DeltaNS3 is Mg2+-dependent as are both helicase and NTPase activities. Mutational analysis shows that the RTPase activity requires an intact NTPase/helicase Walker B motif in the helicase core, consistent with the fact that such motifs are involved in the coordination of Mg2+. The R513A substitution in the C-terminal domain of DeltaNS3 abrogates helicase activity and strongly diminishes RTPase activity, indicating that both activities are functionally coupled. DV RTPase seems to belong to a new class of Mg2+-dependent RTPases, which use the active center of the helicase/NTPase catalytic core in conjunction with elements in the C-terminal domain. 相似文献
9.
Plamont MA Chasseigneaux S Delasnerie-Lauprêtre N Beaudry P Peoc'h K Laplanche JL 《Neuroscience letters》2003,344(2):132-134
Prion diseases are characterized by the accumulation in the brain of a misfolded and protease-resistant form of the prion protein (PrP(c)). PrP(c) contains an amyloidogenic, neurotoxic sequence that is essential for conversion into PrP(Sc), the pathological isoform. During normal processing, PrP(c) is cleaved at a site within this sequence, and this cleavage is thought to destroy the amyloidogenic potential of the protein. ADAM10, a disintegrin and metalloprotease that plays a key role in the pathogenesis of Alzheimer's disease, was recently shown to use PrP(c) as a substrate. We investigated whether variability in the ADAM10 gene could contribute to the pathogenesis of Creutzfeldt-Jakob disease (CJD), by analyzing a single nucleotide polymorphism (SNP) within ADAM10, as a genetic marker potentially in linkage disequilibrium with a functional polymorphism, in patients with sporadic or variant CJD. We observed no significant differences in ADAM10 genotype or allele frequencies between CJD patients and healthy individuals. Moreover, the distribution of ADAM10 SNP genotypes and alleles did not differ between groups of patients based on genotype at the polymorphic codon 129 of the prion protein gene--the sole major genetic risk factor for CJD identified to date. Our data indicate that ADAM10 is unlikely to confer genetic susceptibility to CJD. 相似文献
10.
Impaired hair follicle morphogenesis and cycling with abnormal epidermal differentiation in nackt mice,a cathepsin L-deficient mutation 总被引:1,自引:0,他引:1 下载免费PDF全文
Benavides F Starost MF Flores M Gimenez-Conti IB Guénet JL Conti CJ 《The American journal of pathology》2002,161(2):693-703
We previously described an autosomal-recessive mutation named nackt (nkt) exhibiting partial alopecia associated with CD4(+) T-cell deficiency. Also, we recently reported that nkt (now Ctsl(nkt)) comprises a deletion in the cathepsin L (Ctsl) gene. Another recent study reported that Ctsl knockout mice have CD4(+) T-cell deficiency and periodic shedding of hair, which recapitulate the nkt mutation and the old furless (fs) mutation. The current study focuses on the dermatological aspects of the nkt mutation. Careful histological analysis of skin development of homozygous nkt mice revealed a delayed hair follicle morphogenesis and late onset of the first catagen stage. The skin of Ctsl(nkt)/Ctsl(nkt) mice showed mild epidermal hyperplasia and hyperkeratosis, severe hyperplasia of the sebaceous glands, and structural alterations of hair follicles. Epidermal differentiation seems to be affected in nkt skin, with overexpression of involucrin and profilaggrin/filaggrin along with focal areas of keratin 6 expression in the interfollicular epidermis. Severe epidermal hyperplasia, acanthosis, orthokeratosis, and hyperkeratosis were only observed in mice maintained in nonpathogen-free environments. The analysis of Rag2-/- Ctsl(nkt)/Ctsl(nkt) double-mutant mice indicates that the skin defect remains under the absence of T and B cells. This animal model provides in vivo evidence that cysteine protease cathepsin L plays a critical role in hair follicle morphogenesis and cycling, as well as epidermal differentiation. 相似文献