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1.
Gynecol Obstet Fertil Senol ; 51(9): 393-399, 2023 09.
Artículo en Francés | MEDLINE | ID: mdl-37295716

RESUMEN

OBJECTIVES: To evaluate the use of simulation among French Obstetrics and Gynecology residency programs. METHODS: A survey was conducted with all 28 French residency program directors. The questionnaire covered equipment and human resources, training programs, types of simulation tools and time spent. RESULTS: Of the cities hosting a residency program, 93% (26/28) responded regarding equipment and human resources, and 75% (21/28) responded regarding training program details. All respondents declared having at least one structure dedicated to simulation. A formal training program was reported by 81% (21/26) of cities. This training program was mandatory in 73% of the cases. There was a median number of seven senior trainers involved, three of whom had received a specific training in medical education. Most of declared simulation activities concerned technical skills in obstetrics and surgery. Simulations to practice breaking bad news were offered by 62% (13/21) of cities. The median number of half-days spent annually on simulation training was 55 (IQR: 38-83). CONCLUSION: Simulation training is now widely available among French residency programs. There remains heterogeneity between centers regarding equipment, time spent and content of simulation curricula. The French College of Teachers of Gynecology and Obstetrics has proposed a roadmap for the content of simulation-based training based on the results of this survey. An inventory of all existing "train the trainers" simulation programs in France is also provided.


Asunto(s)
Ginecología , Internado y Residencia , Obstetricia , Entrenamiento Simulado , Femenino , Embarazo , Humanos , Obstetricia/educación , Ginecología/educación , Encuestas y Cuestionarios
2.
Eur J Med Genet ; 66(6): 104748, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-36948288

RESUMEN

Differences of sex development (DSDs) are a group of congenital conditions characterized by a discrepancy between chromosomal, gonadal, and genital sex development of an individual, with significant impact on medical, psychological and reproductive life. The genetic heterogeneity of DSDs complicates the diagnosis and almost half of the patients remains undiagnosed. In this context, chromosomal imbalances in syndromic DSD patients may help to identify new genes implicated in DSDs. In this study, we aimed at describing the burden of chromosomal imbalances including submicroscopic ones (copy number variants or CNVs) in a cohort of prenatal syndromic DSD patients, and review their role in DSDs. Our patients carried at least one pathogenic or likely pathogenic chromosomal imbalance/CNV or low-level mosaicism for aneuploidy. Almost half of the cases resulted from an unbalanced chromosomal rearrangement. Chromosome 9p/q, 4p/q, 3q and 11q anomalies were more frequently observed. Review of the literature confirmed the causative role of CNVs in DSDs, either in disruption of known DSD-causing genes (SOX9, NR0B1, NR5A1, AR, ATRX, …) or as a tool to suspect new genes in DSDs (HOXD cluster, ADCY2, EMX2, CAMK1D, …). Recurrent CNVs of regulatory elements without coding sequence content (i.e. duplications/deletions upstream of SOX3 or SOX9) confirm detection of CNVs as a mean to explore our non-coding genome. Thus, CNV detection remains a powerful tool to explore undiagnosed DSDs, either through routine techniques or through emerging technologies such as long-read whole genome sequencing or optical genome mapping.


Asunto(s)
Aneuploidia , Translocación Genética , Embarazo , Femenino , Humanos , Estudios Retrospectivos , Mosaicismo , Variaciones en el Número de Copia de ADN , Cromosomas , Diagnóstico Prenatal/métodos
3.
Eur J Obstet Gynecol Reprod Biol ; 252: 198-205, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32622104

RESUMEN

OBJECTIVE: To report complications of Acute Fatty Liver of pregnancy (AFLP), a rare liver disease of pregnancy, and identify prognostic factors for mothers and children. STUDY DESIGN: We conducted a retrospective descriptive study over 18 years in three French maternities. Demographic, clinical, biological data, and outcomes of patients and their infants were reviewed. RESULTS: 142,450 pregnancies from centers were studied. Eighteen patients with AFLP were identified The prevalence of AFLP was estimated as 1/7,914 pregnancies. Prolonged prothrombin time was identified as a risk factor of maternal complications (OR = 0.86, p = 0.0493). Gestational age at delivery was the only risk factor associated with fetal or neonate complications (OR = 0.37, p = 0.0417). One boy died of previously undiagnosed ß-oxidation deficiency at eight months. CONCLUSION: In AFLP, prothrombin time must be carefully monitored to anticipate major maternal complications. Infants born to mothers with ALFP should be screened as early as possible for mitochondrial fatty acid oxidation deficiency.


Asunto(s)
Hígado Graso , Complicaciones del Embarazo , Hígado Graso/epidemiología , Femenino , Humanos , Recién Nacido , Masculino , Embarazo , Complicaciones del Embarazo/epidemiología , Pronóstico , Estudios Retrospectivos
4.
J Gynecol Obstet Hum Reprod ; 49(8): 101847, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-32619725

RESUMEN

OBJECTIVES: To provide up-to-date evidence-based guidelines for the management of smoking cessation during pregnancy and the post-partum period. STUDY DESIGN: A systematic review of the international literature was undertaken between January 2003 and April 2019. MEDLINE, EMBASE databases and the Cochrane library were searched for a range of predefined key words. All relevant reports in English and French were classified according to their level of evidence ranging from 1(highest) to 4(lowest). The strength of each recommendation was classified according to the Haute Autorité de Santé (French National Authority for Health) ranging from A (highest) to C (lowest). RESULTS: "Counselling", including all types of non-pharmacological interventions, has a moderate benefit on smoking cessation, birth weight and prematurity. The systematic use of measuring expired air CO concentration does not influence smoking abstinence, however, it may be useful in assessing smoked tobacco exposure prior to and after quitting. The use of self-help therapies and health education are recommended in helping pregnant smokers quit and should be advised by healthcare professionals. Nicotine replacement therapies (NRT) may be prescribed to pregnant women who have failed to stop smoking after trying non-pharmacological interventions. Different modes of delivery and dosages can be used in optimizing their efficacy. Smoking in the postpartum period is essential to consider. The same treatment options as during pregnancy can be used. CONCLUSION: Smoking during pregnancy concerns more than a hundred thousand women each year in France resulting in a major public health burden. Healthcare professionals should be mobilised to employ a range of methods to reduce or even eradicate it.


Asunto(s)
Atención Prenatal/métodos , Cese del Hábito de Fumar , Fumar , Dispositivos para Dejar de Fumar Tabaco , Adulto , Consejo , Femenino , Francia , Educación en Salud , Humanos , Recién Nacido , Periodo Posparto , Embarazo , Complicaciones del Embarazo/epidemiología , Factores de Riesgo , Fumar/efectos adversos , Cese del Hábito de Fumar/métodos
5.
Gynecol Obstet Fertil Senol ; 48(7-8): 567-577, 2020.
Artículo en Francés | MEDLINE | ID: mdl-32247092

RESUMEN

INTRODUCTION: Smoking during pregnancy leads to fetal passive smoking. It is associated with several obstetrical complications and is a major modifiable factor of maternal and fetal morbidity. Long-term consequences also exist but are less well known to health professionals and in the general population. METHODS: Consultation of the Medline® database. RESULTS: Maternal smoking during pregnancy is associated in the offspring with sudden infant death syndrome (NP2), impaired lung function (NP2), lower respiratory infections and asthma (NP2), overweight and obesity (NP2), cancers (NP3), risk of tobacco use, nicotine dependence and early smoking initiation (NP2). Unadjusted analyses show associations between in utero tobacco exposure and cognitive deficits (NP3), impaired school performance (NP3) and behavioral disorders in children (NP2), which are in a large part explained by environmental factors. There is a cross-generational effect of smoking during pregnancy. For example, an increased risk of asthma is observed in the grandchildren of smoking women (NP4). The respective roles of ante- and post-natal smoking remain difficult to assess. CONCLUSION: These results highlight the importance of prevention measures against tobacco use in the general population, as well as screening measures and support for smoking cessation before or at the beginning of the pregnancy.


Asunto(s)
Efectos Tardíos de la Exposición Prenatal , Fumar , Adulto , Niño , Femenino , Humanos , Embarazo , Efectos Tardíos de la Exposición Prenatal/epidemiología , Fumar/efectos adversos
6.
Gynecol Obstet Fertil Senol ; 48(7-8): 612-618, 2020.
Artículo en Francés | MEDLINE | ID: mdl-32247096

RESUMEN

INTRODUCTION: The consequences of smoking have been studied more during pregnancy than during breastfeeding. There is a passage of nicotine and other substances in breast milk and some modifications of milk composition. The objectives of this chapter are to study the benefits of breastfeeding in women who smoke, and the adaptation of smoking, medication and behavioral habits in case of incomplete withdrawal to better guide women. METHODS: The Medline database, the Cochrane Library and foreign guidelines from 1999 to 2019 have been consulted. RESULTS: The conservation of the benefit of breastfeeding in smokers with regard to the prevention of respiratory infections, infantile colic, cognitive deficits, obesity, sudden infant death, is not known to date. It is therefore not recommended to include smoking status in the choice of feeding mode for the newborn (professional agreement). However, since breastfeeding is a factor associated with a reduction in smoking and/or withdrawal (NP2), it is recommended to promote breastfeeding in non-weaned women in order to limit smoking (grade B). The use of nicotine replacement therapy is possible during breastfeeding (professional agreement). In the absence of data, bupropion (Zyban®) and varenicline (Champix®) are not recommended for women who are breastfeeding (professional agreement). A free interval between smoking and breastfeeding reduces the concentration of nicotine in milk (NP4). For non-weaned women who are breastfeeding, it is therefore recommended not to smoke just before breastfeeding (professional agreement). CONCLUSION: The results indicate that breastfeeding is possible in smokers, although less often initiated by them. If the conservation of its benefits for the child is not demonstrated to date, breastfeeding allows the mother to limit smoking.


Asunto(s)
Lactancia Materna , Cese del Hábito de Fumar , Niño , Femenino , Humanos , Lactante , Recién Nacido , Nicotina , Embarazo , Fumar/efectos adversos , Dispositivos para Dejar de Fumar Tabaco
7.
Gynecol Obstet Fertil Senol ; 48(7-8): 539-545, 2020.
Artículo en Francés | MEDLINE | ID: mdl-32289497

RESUMEN

OBJECTIVES: To provide up-to-date evidence-based guidelines for the management of smoking cessation during pregnancy. METHODS: Systematic review of the international literature. We identified papers published between January 2003 and April 2019 in Cochrane PubMed, and Embase databases with predefined keywords. All reports published in French and English relevant to the areas of focus were included and classified according the level of evidence ranging from 1 (highest) to 4 (lowest). The strength of the recommendations was classified according to the Haute Autorité de santé, France (ranging from A, highest to C, lowest). RESULTS: "Counseling", involving globally all kind of non-pharmacological interventions, has a modest benefit on smoking cessation, birth weight and prematurity. Moderate physical activity did not show a significant effect on smoking cessation. The systematic use of feedback by measuring the expired air carbon monoxide concentration do not influence smoking abstinence but it may be used in establishing a therapeutic alliance. The use of self-help interventions and health education are recommended in helping pregnant smokers quit. The prescription of nicotine replacement therapies (NRT) may be offered to any pregnant woman who has failed stopping smoking without medication This prescription can be initiated by the health care professional taking care of the pregnant woman in early pregnancy. There is no scientific evidence to propose the electronic cigarette for smoking cessation to pregnant smokers; it is recommended to provide the same advice and to use methods that have already been evaluated. The use of waterpipe (shisha/narghile) during pregnancy is associated with decreased fetal growth. It is recommended not to use waterpipe during pregnancy. Breastfeeding is possible in smokers, but less often initiated by them. Although its benefit for the child's development is not demonstrated to date, breastfeeding allows the mother to reduce or stop smoking. The risk of postpartum relapse is high (up to 82% at 1 year). The main factors associated with postpartum abstinence are breastfeeding, not having a smoker at home, and having no symptoms of postpartum depression. CONCLUSIONS: Smoking during pregnancy concerns more than hundred thousand women and their children per year in France. It is a major public health burden. Health care professionals should be mobilized for reducing or even eradicating it.


Asunto(s)
Sistemas Electrónicos de Liberación de Nicotina , Cese del Hábito de Fumar , Niño , Femenino , Humanos , Nicotina , Embarazo , Fumar , Prevención del Hábito de Fumar , Dispositivos para Dejar de Fumar Tabaco
9.
J Neonatal Perinatal Med ; 12(4): 457-464, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31282431

RESUMEN

BACKGROUND: The objective of the study was to assess perinatal grief experienced after continuing pregnancy and comfort care in women diagnosed with lethal fetal condition compared with termination of pregnancy for fetal anomaly (TOPFA). METHODS: This was a retrospective observational study which included women who chose to continue their pregnancy after the diagnosis of lethal fetal condition with comfort care support at birth at the Prenatal Diagnosis Center of Rennes Hospital from January 2007 to January 2017. Women were matched with controls who underwent TOPFA for the same type of fetal anomaly, gestational age at diagnosis and year. Women were evaluated by a questionnaire including the Perinatal Grief Scale. RESULTS: There were 28 patients in the continuing pregnancy group matched with 56 patients in the TOPFA group. Interval between fetal loss and completion of questionnaire was 6±3 years. Perinatal grief score was similar at 61±22 vs 58±18 (p = 0.729) in the continuing pregnancy and TOPFA groups, respectively. Women in the TOPFA group expressed more guilt. The cesarean-section rate in the continuing pregnancy group was 25%. CONCLUSION: Perinatal grief experienced by women opting for continuing pregnancy and comfort care after diagnosis of a potentially lethal fetal anomaly is not more severe than for those choosing TOPFA.


Asunto(s)
Aborto Inducido/estadística & datos numéricos , Conducta de Elección , Enfermedades Fetales/diagnóstico , Pesar , Cuidados Paliativos/métodos , Diagnóstico Prenatal/psicología , Aborto Inducido/psicología , Adulto , Femenino , Enfermedades Fetales/psicología , Edad Gestacional , Humanos , Recién Nacido , Comodidad del Paciente , Embarazo , Escalas de Valoración Psiquiátrica , Estudios Retrospectivos
10.
J Gynecol Obstet Hum Reprod ; 46(5): 439-443, 2017 May.
Artículo en Inglés | MEDLINE | ID: mdl-28412314

RESUMEN

OBJECTIVE: The objective of this study is to assess progress made in the ultrasound (US) measurement of femur length (FL) by students after one hour of training on US obstetric simulators. MATERIALS AND METHODS: Medical residents and midwives registered for the 2016 French national foetal US diploma were invited to a 1-hour US training course with simulators. The time to acquire the FL plane with changing foetal presentation was prospectively measured before and after the training. Every image was recorded, and quality criteria were assessed. RESULTS: Thirty new learners trained in foetal US were evaluated. The time needed to measure the FL was significantly shorter in the post-test versus the pre-test (86s versus 125, P=0.015). The quality criteria were statistically similar before and after training regarding the angle to horizontal (10.0° versus 9.6°, P=0.84) and FL (31.3mm versus 32.0mm, P=0.15). CONCLUSION: The time needed to obtain the FL plane was reduced by 30% after a 1-hour US simulation training session.


Asunto(s)
Pesos y Medidas Corporales/métodos , Partería , Obstetricia/educación , Entrenamiento Simulado , Estudiantes de Medicina , Ultrasonografía Prenatal/métodos , Ultrasonografía Prenatal/normas , Adulto , Pesos y Medidas Corporales/normas , Desarrollo Óseo , Competencia Clínica , Evaluación Educacional , Femenino , Fémur/anatomía & histología , Fémur/diagnóstico por imagen , Peso Fetal , Feto , Francia , Humanos , Internado y Residencia , Presentación en Trabajo de Parto , Masculino , Embarazo , Estándares de Referencia
11.
Adv Simul (Lond) ; 2: 24, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-29450025

RESUMEN

BACKGROUND: Ultrasonography (US) is an essential tool for the diagnosis of acute gynecological conditions. General practice (GP) residents are involved in the first-line management of gynecologic emergencies. They are not familiar with US equipment. Initial training on simulators was conducted.The aim of this study was to evaluate the impact of simulation-based training on the quality of the sonographic images achieved by GP residents 2 months after the simulation training versus clinical training alone. METHODS: Young GP residents assigned to emergency gynecology departments were invited to a one-day simulation-based US training session. A prospective controlled trial aiming to assess the impact of such training on TVS (transvaginal ultrasound scan) image quality was conducted. The first group included GP residents who attended the simulation training course. The second group included GP residents who did not attend the course. Written consent to participate was obtained from all participants. Images achieved 2 months after the training were scored using standardized quality criteria and compared in both groups. The stress generated by this examination was also assessed with a simple numeric scale. RESULTS: A total of 137 residents attended the simulation training, 26 consented to participate in the controlled trial. Sonographic image quality was significantly better in the simulation group for the sagittal view of the uterus (3.6 vs 2.7, p = 0.01), for the longitudinal view of the right ovary (2.8 vs 1.4, p = 0.027), and for the Morrison space (1.7 vs 0.4, p = 0.034), but the difference was not significant for the left ovary (2.9 vs 1.7, p = 0.189). The stress generated by TVS after 2 months was not different between the groups (6.0 vs 4.8, p = 0.4). CONCLUSION: Simulation-based training improved the quality of pelvic US images in GP residents assessed after 2 months of experience in gynecology compared to clinical training alone.

12.
Connect Tissue Res ; 13(3): 261-7, 1985.
Artículo en Inglés | MEDLINE | ID: mdl-3159543

RESUMEN

Leg immobilization with or without soleus muscle denervation was studied in young rabbits. Muscle and tendon were maintained in extension, i.e., in the most lengthened position. Length measurements performed on sarcomeres, muscle fibers and tendon-plus-muscle complexes suggest the following progression in tendon growth rates: normal less than denervated-extended less than innervated-extended. Collagen reticulation was studied as a function of fiber location along these tendons by measuring hydrothermal isometric tension (HIT). Large variations were observed depending on fiber location, and significant modifications were induced by immobilization in extension. The results are discussed in relation to stress as a possible factor controlling collagen maturation in connective tissues.


Asunto(s)
Adaptación Fisiológica , Colágeno/metabolismo , Músculos/fisiología , Tendones/fisiología , Animales , Pierna , Músculos/anatomía & histología , Conejos , Restricción Física , Estrés Mecánico , Tendones/anatomía & histología
13.
Connect Tissue Res ; 13(2): 145-55, 1985.
Artículo en Inglés | MEDLINE | ID: mdl-3157542

RESUMEN

The relaxation time of hydrothermal isometric tensions (HIT) was measured in different tissues during collagen hydrolysis. This hydrolysis was shown to have the same activation energy in all skin samples studied, whatever the species and age. Therefore, variations in the HIT relaxation half-time at the boiling point, exclusively reflected variations in the reticulation degree of the stable infinite network of denatured collagen. Stable collagen reticulation was studied in human skin from birth to 70 yrs of age in 113 biopsies, by measuring the relaxation half-time of hydrothermal isometric tension (HIT) at boiling point. This time was observed to vary in three different ways as a function of age: 1) from birth to eight or 10 yrs and from 14-15 yrs until adulthood, it increased constantly, and at the same rate; 2) during early puberty, the striking observation was the dramatic decrease of relaxation time value which remained low for 4-5 yrs thereafter, and 3) from adulthood to 70 yrs of age, relaxation time values were scattered along several plateaux, apparently separated by similar incremental steps. A parallel study on rat and pig skin showed a similar age-related evolution for collagen stable reticulation i.e., a sudden drop of reticulation at puberty, and low values for several months thereafter, followed by a linear increase, at the same rate as that observed for human skin. The study of collagen reticulation in various pathological situations may help to clarify and increase our understanding of the different mechanisms involved in collagen modifications during in vivo growth and aging.


Asunto(s)
Envejecimiento , Colágeno/metabolismo , Piel/metabolismo , Adolescente , Adulto , Anciano , Animales , Niño , Preescolar , Femenino , Humanos , Hidrólisis , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Ratas , Ratas Endogámicas , Porcinos
14.
Connect Tissue Res ; 11(2-3): 199-206, 1983.
Artículo en Inglés | MEDLINE | ID: mdl-6224643

RESUMEN

Variations in hydrothermal isometric tension (HIT) were recorded in tendons, ligaments, skin, blood vessels, nerves, palatal mucosa, lungs, muscles, cartilages, demineralized bones and dentine from donors of different ages and species. The curves obtained during a linear rise in temperature from 37 degrees C to 100 degrees C at a rate of 1.15 degrees C/min were classified into three major families, A, B and C, depending on whether these curves displayed an early maximum, two shoulders or a late maximum. The ratio of heat-labile to heat-stable cross-links in the tissue's collagen network was shown to determine the type of curve obtained, but the genetic types of collagen in the tissue and the amount and quality of its noncollagenous components were not important in this respect. These results are discussed in the light of the accepted view that HIT variations are due to the rubber-elastic properties of gelatin.


Asunto(s)
Colágeno/fisiología , Tejido Conectivo/fisiología , Animales , Aorta/fisiología , Fenómenos Biofísicos , Biofisica , Huesos/fisiología , Cartílago/fisiología , Colágeno/genética , Peces , Cobayas , Humanos , Ligamentos/fisiología , Músculos/fisiología , Ratas , Fenómenos Fisiológicos de la Piel , Estrés Mecánico , Tendones/fisiología
15.
Connect Tissue Res ; 11(1): 35-44, 1983.
Artículo en Inglés | MEDLINE | ID: mdl-6221878

RESUMEN

The ability of tendon to adapt its length to imposed conditions was tested in rat soleus. Shortening of one tibia left tendon insertions intact, but reduced the distance between them. Tendon lengths were found to decrease after a short period of recovery (1 or 2 months) whether surgery was performed in young or adult animals. Comparison of tibia and tendon length correlation in control rats of different ages and in experimental animals showed that adaptation was more complete in young rats than in adult rats. A long period of recovery seemed to improve adaptation only in young rats. Hydrothermal isometric tension measurements indicated that collagen remodeling occurred during tendon adaptation to bone length, with the process being more marked at the muscle-tendon junction.


Asunto(s)
Adaptación Fisiológica , Diferencia de Longitud de las Piernas/fisiopatología , Músculos/fisiopatología , Tendones/fisiopatología , Factores de Edad , Animales , Miembro Posterior , Contracción Isométrica , Masculino , Ratas , Ratas Endogámicas , Tendones/anatomía & histología , Resistencia a la Tracción , Tibia/cirugía
16.
Biochim Biophys Acta ; 717(2): 295-300, 1982 Aug 06.
Artículo en Inglés | MEDLINE | ID: mdl-7115770

RESUMEN

The curves obtained for skin samples of different ages and species by hydrothermal isometric tension ("HIT") measurement are compared to those obtained by differential scanning calorimetry (DSC) under the same thermal conditions (for a rise in temperature at a rate of 1.0 degrees C/min). Collagen denaturation, observed by DSC, directly affects the kinetics of the tension variations in the first part of the "HIT" curves, including the early peak due to the presence and destruction of the heat-labile cross-links in the collagen network. The presence of cross-links is in term shown to delay collagen denaturation to an extent which depends in part on their heat-stability. The final part of the "HIT" curves reflecting the effects of heat in the stable polymeric collagen network is no longer affected by collagen denaturation. Thus, both "HIT" and DSC are useful methods to evaluate collagen reticulation in connective tissues.


Asunto(s)
Colágeno/metabolismo , Fenómenos Fisiológicos de la Piel , Envejecimiento , Animales , Rastreo Diferencial de Calorimetría , Humanos , Cinética , Masculino , Persona de Mediana Edad , Ratas , Ratas Endogámicas , Piel/crecimiento & desarrollo , Estrés Mecánico
17.
Connect Tissue Res ; 9(4): 253-62, 1982.
Artículo en Inglés | MEDLINE | ID: mdl-6215209

RESUMEN

Hydrothermal Isometric Tension (HIT) relaxation was observed at the boiling point in rat, cat and human skin samples of different ages, after raising the temperature from 37 degrees to 100 degrees C at a rate of 1.15 degrees C/min. A Maxwellian relaxation to nearly zero was observed at the boiling point. A given velocity constant characterized a given tissue whether experiments were performed under pressure or under tensile stress. However, the velocity constant of the relaxation decreased as a function of age for all three species during the period studied. Moreover, the velocity constant decreased at the same constant rate for skin samples of cats aged 1 to nearly 5 years, of rats aged from 9 to 28 months and of children from birth to 10 years. We propose a model, based on the well known rubber-elastic properties of the denatured collagen network. In this model (1) HIT decreases as an exponential function of time during bond scission along the polymeric chains; (2) the velocity constant of the relaxation process is proportional to the rate of bond rupture and inversely proportional to the number of stable polymeric chains originally present per unit volume; (3) the evolution of the velocity constant as a function of aging finds an explanation. The HIT test should find useful applications in pathology and pharmacology, since it provides rapid, precise information on the stable state of collagen reticulation in small biopsies.


Asunto(s)
Colágeno/metabolismo , Piel/metabolismo , Factores de Edad , Animales , Gatos , Niño , Preescolar , Elasticidad , Femenino , Humanos , Lactante , Recién Nacido , Modelos Biológicos , Conformación Proteica , Desnaturalización Proteica , Ratas , Ratas Endogámicas , Temperatura , Resistencia a la Tracción
19.
Calcif Tissue Int ; 33(4): 403-7, 1981.
Artículo en Inglés | MEDLINE | ID: mdl-6794879

RESUMEN

Chondrocytes from articular and growth plate cartilage were grown in primary culture. The lipid content, distribution into different types, as well as the fatty acid patterns of these lipids were compared when the cells had reached stationary phase and were synthesizing maximal amounts of proteoglycans. Numerous significant differences were observed, depending on the origin of the chondrocytes. In particular, growth plate chondrocytes showed increased dry weight, increased lipid content (phosphatides and triglycerides), and decreased cholesterol to phosphatide ratio when compared to articular chondrocytes; they also incorporated more of C18:1 and less C16:0 into their major lipid types. Whether these differences arise from specific metabolic regulation or are a consequence of chondrocyte organization in primary culture remains unclear.


Asunto(s)
Cartílago/análisis , Lípidos/análisis , Animales , Cartílago Articular/análisis , Células Cultivadas , Colesterol/análisis , Ácidos Grasos/análisis , Glicéridos/análisis , Fosfolípidos/análisis , Conejos
20.
Ann Biol Clin (Paris) ; 39(4): 165-73, 1981.
Artículo en Francés | MEDLINE | ID: mdl-7305085

RESUMEN

The type of collagen reticulation exerts an influence on biological, physiological and mechanical properties of tissues, thus the utility of its study. Chemical techniques allow both localization and evaluation of levels and origin (Schiff base or aldol) of reducible bonds in collagen. Physical techniques allow evaluation of the thermolability or thermostability, as well as the degree of collagen reticulation in a given tissue for all collagen bridges. Results by these methods have shown that the mode of tissular collagen reticulation evolves from the embryonic phase to senescence, the rate varying as a function of the tissue and species of the donor. Thus, during tissular reparation, the newly formed collagen network itself undergoes transformations. Cicatricial tissue thus gives rise to an anisotropic zone in particular in terms of mechanical properties, in the organ. This can have grave pathological consequences. In addition to these wide areas of study, a certain number of specific diseases, frequently genetic, show pathological changes in collagen polymerization, the molecular mechanisms for which are now becoming better known.


Asunto(s)
Colágeno/metabolismo , Enfermedades Óseas/metabolismo , Estabilidad de Medicamentos , Humanos , Sustancias Macromoleculares , Bases de Schiff , Termodinámica
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