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Biomedical subjects

M Laude

Publications and source records attributed to M Laude.

At least 19 recordsLinked to original sources

Relationship between ultrastructure and biomechanical properties of the knee meniscus.

The purpose of this study was to determine the biomechanical properties of the knee meniscus and to relate them to its ultrastructure. The knee joint menisci are semicircular, fibrocartilaginous structures interposed between the femoral and tibial condyles. For a long time, they were considered to be embryologic vestiges. This study describes the response of the knee joint meniscus to circumferential, radial and axial compressive forces. The results show an anisotropic response of the knee joint meniscus to unconfined compression. The Young's modulus increased approximately twofold between vertical and circumferential or radial directions with a 10 mm/min-compression rate. This response is probably a direct consequence of the orientation of collagen fibres.

Animals↗

[Anatomical basis of the extraspinal cord compression].

Knowledge of anatomical landmarks of the spinal cord within the vertebral foramen is essential to understand the pathogenesis of spinal cord compression by tumor growth. The spinal cord can spread in the intervertebral foramen, the epidural space, the vertebral body, and the posterior neural arch. The morphology of the spinal cord, the relations of the spinal roots with the vertebrae, the principal fiber tracts, the spinal membranes, and the arterial and venous distribution are described in order to explain and analyze signs and disorders caused by the most frequent tumors involved in spinal cord compression.

Humans↗

Relationships of the palmar cutaneous branch of the median nerve: a morphometric study.

Treatment of carpal tunnel syndrome consists in decompression of the median nerve by section of the flexor retinaculum. Usually, this surgery improves the disease with disappearance of the symptoms. However, some painful sequelae may remain such as painful discharges, paresthesiae or permanent anesthesia of the base of the thumb or of the scar related to an injury of the palmar cutaneous branch of the median nerve (PCBm). This study was performed to define the accurate emergence and the anatomic characteristics of this nerve in relation to stable landmarks. Moreover, it assessed the importance of the visual identification of the branch during section of the flexor retinaculum. Thirty-five hands were dissected under macroscopic examination and under magnification of the thinnest branches. Measurements were performed with a caliper and the forearm in supination. Determination of the bistyloid line showed variability in the location of the distal wrist crease. Thus, it could not be used as a landmark to locate the PCBm. The palmar cutaneous branch is the distal collateral branch of the median nerve in the forearm. It emerges on its radial side, on average 44.3 mm before the bistyloid line. It courses in line with the third finger and perforates the antebrachial aponeurosis about 5.7 mm from the bistyloid line. This emergence can be located in the palm, where it can be injured if the incision is performed in line with the third finger. The PCBm usually ends in the palm by division into two or three branches. The lateral branch supplies the skin of the thenar eminence while the medial, usually shorter branch supplies the midline part of the palm. This study has shown the importance of performing the cutaneous incision in line with the fourth finger to avoid injury to the PCBm.

Carpal Tunnel Syndrome↗

[Anatomy of the external laryngeal nerve: surgical implications. Report of 30 dissections].

OBJECTIVES: This anatomic study aimed to detail the anatomy of the external laryngeal nerve and to determine the possible variations of nerves at risk. MATERIAL AND METHOD: Fifteen cadavers (30 nerves) were dissected. The peri pharyngo laryngeal route, the anatomic rapports, the branches of division and the distal penetration point of the external laryngeal nerve were noted. RESULTS: The external laryngeal nerve gave branches to the inferior pharyngeal constrictor muscle in 90% of cases and to the thyroid gland in 70% of cases. There was an adherence between the nerve and the trunk of the superior thyroid artery in 13.33% of cases. The nerve had a distal superficial route even on the cricothyroid muscle in 6.67% of cases. In one case the nerve was situated close to the medial face of the superior thyroid lobe. DISCUSSION/CONCLUSION: The external laryngeal nerve has numerous anatomic variations. The anatomic variations at risk during thyroid surgery are: an adherence between the nerve and the thyroid artery (or a course of the nerve between the branches of the superior thyroid artery); a superficial distal route; a distal situation close to the medial face of the thyroid lobe. In this study, 7 nerves were considered at risk (23.33% of cases).

Humans↗

The external laryngeal nerve: surgical and anatomic considerations. Report of 50 total thyroidectomies.

This surgical anatomy study aimed to evaluate the possibility of identifying the external laryngeal nerve during thyroid surgery and the possible variations of nerves at risk. Fifty patients underwent total thyroidectomies during a period of 12 months. Using a neurostimulator, the distal motor branch of the external laryngeal nerve was searched. Electrical stimulation of a nervous branch aimed to provoke a global contraction of the cricothyroid in order to identify with certitude the external laryngeal nerve. The external laryngeal nerve was identified in 20% of cases. Its course was, with almost equal frequency, either (1) between the vessels of the superior thyroid pedicle or (2) superficial and anterior to the fascia of the cricothyroid muscle. The external laryngeal nerve is hard to find during thyroid surgery, even with a neurostimulator. It can be vulnerable during thyroid surgery but only in cases of anatomic variations. Searching for the nerve systematically during thyroid surgery does not seem to be useful. Several precautions when dissecting the superior pole of the thyroid gland seem to be necessary and sufficient to respect the external laryngeal nerve.

Adult↗

Comparative histological and biometric study of the coronary, radial and left internal thoracic arteries.

In an attempt to elucidate the causes of occlusion of radial arteries used for coronary artery bypass grafts and to improve the results of these procedures, we studied the biometry and histology of the coronary, radial and left internal thoracic arteries. These arteries were harvested from 20 cadavers (13 males, 7 females). The specimens were calibrated to the various bypass graft sites using coronary calibrators, and were then submitted to histological examination to determine the structure and innervation of the vessel wall. No correlation was observed between the internal calibers of these various arteries, with the exception of the anterior interventricular and right coronary arteries. Intimal changes and the presence of atheromatous plaque were observed in coronary and radial arteries, but never in the internal thoracic artery. Like the coronary arteries and their branches, the radial artery is a muscular artery. Aging of muscular arteries results in thickening of the intima, which becomes fibrotic due to migration of myocytes from the media and duplication of the internal elastic lamina. The media becomes fibrous, hypertrophic or atrophic. The walls of the radial and coronary arteries contain several adventitial nerves (sympathetic and parasympathetic nerve fibers), but these nerve fibers were not observed in the wall of the left internal thoracic artery. In contrast, the internal thoracic artery, like the aorta, is an elastic artery. Aging of elastic arteries is first observed between the ages of 20 and 29 years and is characterized by loss of one or several elastic laminae of the media and more marked intimal thickening, over a variable length. Even if a radial artery's caliber is similar to that of the coronary artery, histological evolution and graft patency depend on its muscular identity.

Aged↗

[Biometry and structure of the left internal thoracic and radial coronary arteries].

In an attempt to elucidate the causes of occlusion of radial arteries for coronary artery bypass grafts, we studied the biometry and histology of the coronary, radial and left internal thoracic arteries of 20 anatomical subjects (13 males and 7 females). These specimens were calibrated to the various bypass graft sites using coronary calibrators, and were then submitted to histological examination to determine the structure of the vessel wall. Our preliminary results show no correlation between the internal calibres of these various arteries. Like the coronary arteries and their branches, the radial artery is a muscular artery. In contrast, the left internal thoracic artery like the aorta, is an elastic artery.

Aged↗

Abuse during and before pregnancy: prevalence and cultural correlates.

This study examined the prevalence of abuse during pregnancy and the influence of cultural norms and acculturation on abuse in 1,004 Mexican American, Puerto Rican, Cuban American, Central American, African American and Anglo American women. Women were recruited from consecutive delivery logs in general community hospitals in Florida and Massachusetts. The Index of Spouse Abuse and the Abuse Assessment Screen ascertained history of adult physical, sexual, and emotional abuse, abuse during pregnancy, and childhood sexual abuse. An Interview Protocol assessed cultural attitudes, acculturation, and demographic information. Hispanic American women, as a whole, did not differ significantly from Anglo American women in their prevalence of abuse during pregnancy, after controlling for sociodemographic variables. However, Cuban American and Central American partners were significantly less likely to abuse their pregnant partners than were other groups even after adjustment. Women who spoke only Spanish (less acculturated) were less likely to report physical abuse from their partners both before and during pregnancy. Cultural norms, such as a partner's belief in wife/mother role supremacy and cultural group acceptability of men hitting women, were significantly positively related to both physical and emotional abuse. Other risk factors for abuse were the abuser not being the biological father of the baby, low income and little education, and being unmarried.

Acculturation↗

Assessment of nutritional status, cognitive development, and mother-child interaction in Central American refugee children.

A cross-sectional study was conducted between July and December 1992 to assess the nutritional status, cognitive development, and mother-child interactions in a group of 153 Nicaraguan refugee children living in Costa Rica. Nutritional status was assessed using anthropometric indices. Cognitive development was assessed with the Bayley Scale of Mental Development. Mother-child interaction was assessed with the Nursing Child Assessment Teaching Scale and Caldwell's Home Observation and Measurement of the Environment Inventory. Correlational analysis was performed to examine the relationship between child cognitive development scores and mother-child interaction measures and also between anthropometric measures and child cognitive development scores. Multiple regression analysis was performed to evaluate the relationship between the mother-child interaction measures and cognitive development scores, after adjusting by anthropometric measures. Thirty-three percent of the children were below the 10th percentile for height-for-age. There was no significant correlation between the total amount of mother-child interaction and child cognitive development. However, certain aspects of the home environment correlated with cognitive development, specifically the manner in which the mother responded emotionally and verbally to her child, and the organization of the child's physical and temporal environment. Multiple regression analysis revealed that the manner in which the mother responded and the child's weight-for-height were important in predicting child cognitive development. The child's weight-for-height and certain aspects of the home environment played an important role in the cognitive development of this refugee population. The findings indicate the importance of assessing nutritional status in this refugee population.

Adult↗

[A novel approach to the biomechanical study of the talocrural joint in man using MRI. Contribution of dynamic images].

A cineradiographic study of the talocrural joint allows a new biomechanical approach of the ankle: MRI with axial and coronal slides were realized: for volume reconstruction in passive movement; scanner was used for axial slides in active movement. There is evidently neither distosis of the bimalleolar grip in dorso- and plantar flexion, nor movement of the lateral malleolus of the fibula, in opposition to the classical description. An anatomical rotation is discussed.

Adult↗

The influence of senescence on craniofacial and cervical morphology in humans.

This study discusses the morphologic evolution of the cranio-facial and cervical bone structures throughout life. A cephalometric study was made on lateral radiographs. The population studied included 84 males and 102 females. Ages ranged from 21 to 101. The cranial structures, superior facial structure, mandible and cervical vertebral column were successively examined. The anteroposterior diameter of the calvarium does not seem to undergo any modification during life. On the other hand, a highly significant increase of the thickness of this structure can be noted. The upper facial structure presents some modification, namely a significant increase of its posterior height. The palatine processus seems to change direction and pivot downwards and forwards. The maxillary sinus does not undergo any changes. The mandible, which is stable in its major axes, shows more malleable sectors which are more especially situated at the level of its body. The study of the cervical vertebral column reveals a loss of overall height, and an increase in the lordosis. The most numerous and most evident morphologic modifications were observed around the age of fifty in both males and females. The fact that these transformations are always commoned and greater in the latter reveals the plausible influence of the menopause. It appears that bone structures of membranous origin are the site of significant modifications compared with structures of endochondral origin, which benefit from a greater stability.

Adult↗

Viscoelastic properties of human arteries. Methodology and preliminary results.

In order to study the biomechanical properties of the arterial wall and to compare arteries with different histologic structures, we designed a device that allows testing of arterial segments under near-physiologic conditions. A hydrodynamic generator simulates systolo-diastolic pressures in an open loop. An intraarterial pressure sensor and a sonomicrometer connected to two piezoelectric crystals placed in diametric opposition on the arterial wall allow computer calculation of compliance, stiffness, midwall radial arterial stress, Young modulus, and incremental modulus for a given arterial segment at a given pressure setting. Seven healthy common carotid artery (CCA) segments and seven healthy (superficial) femoral artery (FA) segments were studied immediately after removal from brain-dead donors between the ages of 18 and 35 years. Histologic examination was performed to determine the density of elastic fibers in the arterial wall. Hysteresis was observed in all segments regardless of pressure settings. Compliance was greater and modulus values and stiffness were lower in CCA than in FA. No evidence of structural change was noted after testing in the circulation loop. These preliminary results open the way to a wide variety of applications for our hydrodynamic circulation loop. Experiments will be undertaken to compare the mechanical properties of arteries before and after cryopreservation.

Adolescent↗

[Hepato-diaphragmatic venous anastomosis (report of a case)].

The authors are reporting an exceptional case of unexpected venous anastomosis between a right inferior diaphragmatic venous and a right hepatic venous discovered during a total hepatectomy before an orthotopic transplantation. Never described in the literature, this abnormality may be explained by the embryology of the transversum septum, junction of the hepatic draft and the draining tracts of the future diaphragm.

Arteriovenous Fistula↗

Two tumor models of curative adoptive chemoimmunotherapy using tumor-infiltrated spleen cells with potent antitumor cytotoxicity stimulated by antigen-sharing tumors.

Previously we have established curative protocols for adoptive chemoimmunotherapy (ACIT) of mice bearing different plasmacytomas that are known to bear cross-reacting antigens: (a) the cure of mice bearing an early-stage, nonpalpable MOPC-315 tumor by a very low dose of cyclophosphamide (10 mg/kg) and cultured MOPC-315-tumor-infiltrated (TI) spleen cells (25 x 10(6)) and (b) the cure of mice bearing a late-stage, relatively drug-resistant, highly metastatic RPC-5 tumor with cyclophosphamide (100 mg/kg) and cultured RPC-5 TI spleen cells (25 x 10(6) - 50 x 10(6)). In both models, the spleen cells were obtained from mice bearing a late-stage tumor and were cultured for 5 days in the presence of polyethyleneglycol 6000 and autochthonous tumor cells as a source of tumor antigen. Here we show that RPC-5 tumor cells could substitute for MOPC-315 tumor cells in the 5-day culture of MOPC-315 TI spleen cells so that they became curative in ACIT for mice bearing an early-stage MOPC-315 tumor. Similarly, MOPC-315 tumor cells could substitute for RPC-5 tumor cells in the 5-day culture of RPC-5 TI spleen cells so that they became curative in ACIT of mice bearing a late-stage RPC-5 tumor. In addition, RPC-5 TI spleen cells cultured with either MOPC-315 or RPC-5 tumor cells were effective in curing all mice bearing an early-stage MOPC-315 tumor by ACIT. However, MOPC-315 TI spleen cells whether cultured with MOPC-315 or RPC-5 tumor cells, were much less effective than cultured RPC-5 TI spleen cells in curing mice bearing a late-stage RPC-5 tumor by ACIT (although the survival of these mice was extended significantly). Interestingly, whereas RPC-5 TI spleen cells cultured with either MOPC-315 or RPC-5 tumor cells were as effective as MOPC-315 TI spleen cells cultured under the same conditions in lysing MOPC-315 tumor cells in vitro, MOPC-315 TI spleen cells that had been cultured with either MOPC-315 or RPC-5 tumor cells exerted a much weaker in vitro cytotoxic T lymphocyte activity against RPC-5 tumor cells than did RPC-5 TI spleen cells that had been cultured under the same conditions.

Animals↗