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Biomedical subjects

O Richard

Publications and source records attributed to O Richard.

At least 19 recordsLinked to original sources
PubMed2006

An anthropometric study of relationships between the clival angle and craniofacial measurements in adult human skulls.

UNLABELLED: STATING BACKGROUND: The clival angle, between the ethmoidal plane and the clival plane, measures the cranial base angulation. Relations between cranial base angulation and facial patterns have been discussed and present contradictory evidence. The aim of this study is to determine whether correlations could be found between the clival angle and craniofacial measurements. METHODS: This study was carried out on a sample of 235 human skulls. Twenty landmarks were marked. The clival angle and 16 other variables were measured and compared using analysis of variance. RESULTS: Statistical analysis showed a relationship between the clival angle and six measurements (P < 0.05). There was a positive correlation between the clival angle and the cranial lengths, the nasomaxillary sagittal measurements and palatal length but the width of the foramen magnum had a negative correlation. No significant relationship was found between the clival angle and the cranial height and widths, the palatal width, the length of the foramen magnum and the mandibular measurements. CONCLUSIONS: The trends found in this study with regard to the craniofacial lengths show that the nasomaxillary complex in humans has a stable position lying beneath the anterior cranial base. Transversal, vertical and mandibular variables have a more independent relationship.

Adolescent↗
PubMed2006

A probable stellar solution to the cosmological lithium discrepancy.

The measurement of the cosmic microwave background has strongly constrained the cosmological parameters of the Universe. When the measured density of baryons (ordinary matter) is combined with standard Big Bang nucleosynthesis calculations, the amounts of hydrogen, helium and lithium produced shortly after the Big Bang can be predicted with unprecedented precision. The predicted primordial lithium abundance is a factor of two to three higher than the value measured in the atmospheres of old stars. With estimated errors of 10 to 25%, this cosmological lithium discrepancy seriously challenges our understanding of stellar physics, Big Bang nucleosynthesis or both. Certain modifications to nucleosynthesis have been proposed, but found experimentally not to be viable. Diffusion theory, however, predicts atmospheric abundances of stars to vary with time, which offers a possible explanation of the discrepancy. Here we report spectroscopic observations of stars in the metal-poor globular cluster NGC 6397 that reveal trends of atmospheric abundance with evolutionary stage for various elements. These element-specific trends are reproduced by stellar-evolution models with diffusion and turbulent mixing. We thus conclude that diffusion is predominantly responsible for the low apparent stellar lithium abundance in the atmospheres of old stars by transporting the lithium deep into the star.

Journal Article↗
PubMed2006

[Patient perception of functional and cosmetic outcome of orthognathic surgery. Retrospective analysis of 45 patients].

INTRODUCTION: Orthognathic surgery is generally indicated for the treatment of maxillo-mandibular deformities. Surgery is performed to repair functional abnormalities, but also has a cosmetic impact. MATERIAL AND METHODS: We conducted a retrospective study of 60 patients who underwent orthognathic surgery in 1996 and 1997 in order to assess patient perception of functional and cosmetic outcome. A questionnaire was sent to all patients one year after their surgery; 45 responded. RESULTS: We noted cosmetic, functional, and psychological changes. Patients considered that the changes were for the better. For functional abnormalities, 88.9% considered their occlusion had improved and 80% their chewing; 73.4% reported psychological improvement stating they had more self-confidence; 97.8% considered their cosmetic aspect had improved. DISCUSSION: This study enabled us to assess patients' perception of surgical outcome. It must be recalled that the patient basically decides to undertake surgery for cosmetic reasons while the surgeon proposes surgery to improve function. The psychological consequences of orthognathic surgery must be taken into account because the impact is considerable.

Attitude to Health↗
PubMed2005

[Malar valgisation in narrow face patients].

Most of the "narrow faces" are secondary to a maxillo-malar hypoplasia consecutive to chronic nasal obstruction. Functional malar valgisation by transmalar osteotomy allows a simple and safe correction of this dysmorphic aspect. Interpositional bone graft and osteosynthesis by miniplate avoid mucous inflammation, maxillary sinusitis and/or relapse observed with use of biomaterials. Correction of "narrow faces" by malar osteotomy is natural and long term results are stable. Functional and esthetic rhinoplasty is often associated. Our clinical experience in 15 cases is reported.

Adult↗
PubMed2005

Severe bone alterations under beta2 agonist treatments: bone mass, microarchitecture and strength analyses in female rats.

AIMS: Beta2 adrenergic agonists are widely used in therapeutics and as doping agents by athletes. However, their effects on bone tissue, especially bone microarchitecture, remain poorly understood. Using three-dimensional (3D) microtomography, dual-energy X-ray absorptiometry, biomechanical testing and enzyme-linked immunosorbent assay, we evaluated the effects of two beta2 agonists, clenbuterol and salbutamol, on bone in growing rats. METHODS: Twelve-week-old Wistar female rats (N = 39), divided in 3 groups, received during 6 weeks either salbutamol (4 mg/kg/day), clenbuterol (2 mg/kg/day) or normal saline (0.5 ml/kg/day) by subcutaneous injections. RESULTS: After 6 weeks, the salbutamol and clenbuterol groups displayed lower bone mineral content (BMC), femoral length and cortical width than controls. Clenbuterol treatment further reduced bone mineral density. Bone microarchitecture was clearly altered by clenbuterol, as evidenced by lower trabecular number (-40.40%; P < 0.001), connectivity and trabecular bone volume (-42.85%; P < 0.001), leading to lower ultimate force. Clenbuterol significantly increased muscle mass (P < 0.01) and reduced fat mass when compared to controls. Salbutamol did not seem to have any effect on bone microarchitecture or body composition. Both beta2 agonists increased the bone resorption marker (C-terminal collagen crosslinks) without any change of a bone formation marker. At the end of the treatment, a drop in leptin was seen in the clenbuterol group only. Leptin levels were correlated with BMC (r = 0.69, P = 0.003). CONCLUSION: These results confirm the deleterious effect of beta2 agonists on bone mass and show the negative effects of clenbuterol on trabecular bone microarchitecture. Bone loss occurred independently from muscle mass but was related to fat mass. A leptin-mediated effect on bone tissue seems likely. These pathophysiological effects may have important consequences in human therapeutics and doping.

Adrenergic beta-Agonists↗
PubMed2005

Submandibular gland endoscopic resection: a cadaveric study.

Recent advancement of head and neck surgery has been marked by the development of endoscopic and video-assisted minimally invasive surgery. This study reports the feasibility of endoscopic submandibular gland resection in human cadavers. Twelve submandibular gland resections were performed in six human cadavers. A 30 degrees angle endoscope and conventional surgical instruments were inserted through two 15 mm submandibular incisions. Dissection was carried out bluntly with scissors in an avascular plane superficial to the gland. No insufflation was needed since transcutaneous sutures lead to effective retraction. Facial vessels, the lingual nerve and Wharton's duct were identified and protected. Vascular ligatures were performed using surgical miniclips. After the procedure, an open submandibular dissection was performed to control the integrity of the anatomical structures. In all cases, the resection of the submandibular gland was successful without the need for an additional incision. Injuries of the facial artery and lingual nerve occurred when the procedure was carried out initially. The operative time decreased with training, from 120 min for the first cases to 35 min for the later ones. In conclusion, endoscopic submandibular gland resection is possible without major difficulty. Training and experience reduce the operative time and the complication rate.

Aged↗
PubMed2005

[Adrenal hypoplasia congenita: four new cases in children].

Adrenal hypoplasia congenita (AHC) is an extremely uncommon disease of early onset. This condition can be lethal in the absence of adapted treatment. Some of these diseases are related to changes in the gene DAX1 that encodes a member of the superfamily of hormone nuclear receptors. It is a transcriptional repressor that is central in the morphogenesis of the adrenals and the gonadic differentiation. Here we report on four cases of X- linked AHC. In the first two familial cases, mutations were identified and mothers were heterozygotes. Abnormally low levels of estriol were evidenced during the pregnancy leading to an early diagnosis and adapted care of the affected male neonates. These children are doing well with a 21-and 20 months follow-up with hormone replacement at the present time. The two last cases corresponded to a contiguous gene syndrome associating AHC to glycerol-kinase deficiency that was revealed respectively at six days and seven years of age by acute adrenal insufficiency.

Adolescent↗
PubMed2005

[Current data and perspectives in minimally invasive video-assisted head and neck surgery: example of endoscopic exploration of the submandibular region].

The purpose of this study was to review the current status of research in this field and to describe the endoscopic technique for resection of the submandibular gland: a 15-mm incision is sufficient for the endoscopic material and gland resection without insufflation. The wound is minimal and the dissection is not traumatic. This innovating technique enables a magnified view of the structures providing an excellent teaching method.

Animals↗
PubMed2005

[Normal mouth opening in the adult French population].

INTRODUCTION: Limitation of mouth opening is a frequent symptom in the pathologies of the temporomandibular joint. The aim of this study is to establish normative basis for this criterion in the French population. MATERIALS AND METHODS: Maximal mouth opening was measured by an electronic goniometric device. Measurements were taken in 228 people (110 men and 126 women) aged between 18 to 84 years, representative of the French population. RESULTS: The average mouth opening is 50.7 7 mm, but it was greater in the male population. It was also greater in tall patients and in younger patients (under 50 years). DISCUSSION: Our study is original because it is based on normal subjects and because our population sample age is the same as that of the French population. Men have a greater mouth opening than women, but this can be due to the fact that they are taller. Mouth opening is wider in young subjects, under 50, because they are younger and because they are taller. Mouth opening is wider in tall patients, whatever their sex or their age.

Adolescent↗
PubMed2005

Late thyroid toxicity in 153 long-term survivors of allogeneic bone marrow transplantation for acute lymphoblastic leukaemia.

The purpose of this study was to identify risk factors for hypothyroidism after bone marrow transplantation (BMT) for high-risk or relapsed acute lymphoblastic leukaemia (ALL) in children. In all, 388 children with acute lymphoblastic leukaemia underwent allogeneic bone marrow transplantation between 1984 and 1994. Overall 5-year survival was 54.6%. Thyroid function was assessed in the 153 patients with more than 5 years of follow-up. In total, 16 patients developed uncompensated hypothyroidism (UH) and 46 compensated hypothyroidism (CH) a median of 2.9 and 2.7 years, respectively, after BMT. Thyroid dysfunction-free survival rates were 73.2% after 5 years and 59.2% after 10 years. Three factors were significantly associated with the onset of hypothyroidism, namely age, bone marrow transplantation in second remission, and single-dose total body irradiation (TBI). Ultrasonography of the thyroid showed nodules in 10 of 35 patients. The median time from BMT to nodule detection was 7.8 years. Cytology (n=5) and surgery (n=4) showed no evidence of thyroid cancer. Four of the 14 patients who received cytoreduction without TBI but with busulphan and cyclophosphamide developed UH (n=2) or CH (n=2). We concluded that children who undergo BMT for ALL are at a high risk of subsequent thyroid dysfunction.

Adolescent↗
PubMed2005

[Impacted canine tooth and the eyebrow: the orbit-eyelid impact of occlusal dysfunction].

The orbital region and the dental occlusion are biomechanicaly interdependant. The maxillary basal bone is located in the orbital region due to the presence of the maxillary sinus. Any trouble of the dental occlusion such as a retained canine can involve a lack of projection of the supra and the infra-orbital rim. This lack of projection of the infra-orbital rim is responsible of lower eyelid fat pad; the lack of projection of the supra-orbital rim is responsible of an eyebrow-forehead ptosis. Clinical variations can be observed according to the side of the preeminent eye.

Adipose Tissue↗
PubMed2005

Effects of acute salbutamol intake during a Wingate test.

To investigate the impact of acute salbutamol intake on performance and selected hormonal and metabolic variables during supramaximal exercise, 13 recreational male athletes performed two 30-second Wingate tests after either placebo (PLA, lactose) or salbutamol (SAL, 4 mg) oral administration, according to a double-blind and randomized protocol. Blood samples collected at rest, end of the Wingate test, recovery (5, 10, 15 min) were tested for growth hormone (GH), insulin (INS), blood glucose (GLU), and lactate determination. We found the peak and mean power performed significantly increased after SAL vs. PLA (PPSAL: 896 +/- 46; PPPLA: 819 +/- 57 W; MPSAL: 585 +/- 27; MPPLA: 534 +/- 35 W, p < 0.05), whereas no change was observed in the fatigue index. Blood glucose and INS were significantly increased by SAL at rest, at the end of the Wingate test, and during the 5 first minutes of recovery (p < 0.05). Plasma GH was significantly decreased by SAL (p < 0.05) during the recovery whereas end-exercise and recovery blood lactate tended but were not significantly increased after SAL vs. PLA. From these data, acute salbutamol intake at therapeutical dosage did appear to improve peak power and mean power during a supramaximal exercise, but the mechanisms involved need further investigation.

Administration, Oral↗
PubMed2005

Effects of short-term salbutamol ingestion during a Wingate test.

The effects of a chronic salbutamol intake (SAL, 12 mg/d during 3 weeks) on changes in body composition, metabolic indices and performance during a 30-second Wingate test were determined in 8 strength-trained male athletes (T) and 7 sedentary male (UT) subjects, according to a double-blind, randomized, cross-over protocol. Blood samples were collected both at rest, at the end of the test, and during passive recovery (5 min, 10 min, 15 min) for leptin (at rest), and blood lactate measurements. No significant changes in lean body mass, fat mass, and leptin were observed with SAL treatment in either group during the trial. Peak power was significantly increased (p < 0.05) after SAL intake in all subjects (T: 11.9 %; UT: 8.3 %) with a decrease in time to peak power with SAL compared to placebo (PLA) (p < 0.05). There was no change in total work performed and in fatigue indices with SAL compared to PLA. Blood lactate was significantly increased after SAL vs. PLA during the recovery (p < 0.05) in all subjects. The data demonstrate that the chronic administration of therapeutic levels of salbutamol increases maximal anaerobic power in man, irrespective of the subjects' training status. This study also rules out any implication of an anabolic effect in this improvement in performance during supramaximal exercise. Further studies are necessary to clarify the mechanisms involved.

Administration, Oral↗
PubMed2004

[Whiplash lesions and temporomandibular joint disorders].

Attributing dysfunction of the temporomandibular joint (TMJ) to whiplash injury is a difficult problem to solve. TMJ disorders do not seem to be secondary to direct articular trauma but rather caused by a postural disorder of the cervical spine. Occlusal disorders and stress further complicate the picture. Four clinical cases illustrate a new hypothetical approach.

Adult↗
PubMed2004

[Basics of esthetic and functional cephalometric analysis of the profile].

We report a new cephalometric method for profile analysis, which uses strictly exobasicranial landmarks: 13 anatomic points, 9 bone points and 4 skin points. The analysis is based on phylogenetic, ontogenetic, anatomic and biomechanical data. Phylogenetic analysis reveals that the occipital plate belongs more to the cranial vault than the base of the skull. Embryology shows that on the midline the facial skull base ends at the spheno-occipital suture and that the overall skull base ends at the basion. The pre-maxillary fuses rapidly to the maxillary, while the pterygoid processes, which belong to the face and not the skull base, fusion very rapidly to the skull base. Revisiting the anatomy of the facial skull base shows that it is prolonged posteriorly medially to meast the synostosic creast and latterally to the glenoid fossae. Further anatomic analysis shows that the dentate and muscular part of the superior level of the facial mass correspond to equivalent parts of the inferior mandibular level. The biomechanical analysis reveals that the anterior pillar passes through the pre-maxillary, ending on the supra-orbital border and the glabella and as such belongs to the face. The posterior pillar follows the pterygoid process ending in the sphenoid. The glabella and these two pillars are taken into account in this new analysis technique.

Adult↗
PubMed2004

[Functional and esthetic cephalometric analysis of the profile].

We report a new cephalometric method for profile analysis, which uses strictly exobasicranial landmarks: 13 anatomic points, 9 bone points and 4 skin points. The analysis is based on phylogenetic, ontogenetic, anatomic and biomechanical data. The face is comprised between a new exobasicranial plane represented by the Nasion-Glenion (Na-Gl) and the classical mandibular plane. These two planes form the angle of facial divergence. Orthogonal projection of the axis of the maxillary incisors and the axis of facial growth on the new basicranial plane is then performed. The upper and lower levels of the facial mass are divided sagittally by four vertical anatomic planes perpendicular to the Francfort plane, accounting for the facial skin profile (cutaneous facial plane), the anterior and posterior facial pillars (premaxillary and postmaxillary planes), and the craniospinal postural plane. The ideal occlusion plane is undistinguishable from the curve of Spee. This new cephalometric method for functional and esthetic profile analysis enables simple rapid and efficient study of the main facial and cervical structures.

Adult↗