In vivo delivery of fluoresceinated dextrans to the murine growth plate: imaging of three vascular routes by multiphoton microscopy.

Bone elongation by endochondral ossification occurs through the differentiation cascade of chondrocytes of cartilaginous growth plates. Molecules from the systemic vasculature reach the growth plate from three different directions: epiphyseal, metaphyseal, and a ring vessel and plexus associated with the perichondrium. This study is an analysis of the real-time dynamics of entrance of fluoresceinated tracers of different molecular weights into the growth plate from the systemic vasculature and tests the hypothesis that molecular weight is a key variable in the determination of both the directionality and the extent of tracer movement into the growth plate. Multiphoton microscopy was used for direct in vivo imaging of the murine proximal tibial growth plate in anesthetized 4- to 5-week-old transgenic mice with green fluorescent protein linked to the collagen II promoter. Mice were given an intracardiac injection of either fluorescein (332.3 Da) or fluoresceinated dextrans of 3, 10, 40, 70 kDa, singly or sequentially. For each tracer, directionality and rate of arrival, together with extent of movement within the growth plate, were imaged in real time. For small molecules (up to 10 kDa), vascular access from all three directions was observed and entrance was equally permissive from the metaphyseal and the epiphyseal sides. Within our detection limit (a few percent of vascular concentration), 40 kDa and larger dextrans did not enter. These results have implications both for understanding systemic and paracrine regulation of growth plate chondrocytic differentiation, as well as variables associated with effective drug delivery to growth plate chondrocytes.

[Innervation of the humerus metaepiphysis in newborn and one year old children]. / Innervatsiia metaépifiza plechevoi kosti novorozhdennykh i detei pervogo goda zhizni.

Analysis of home and foreign literature on metaepiphyseal cartilage innervation and blood supply was presented, data on these organ diseases substantiate theoretical and clinical significance of the study was performed. Using macro-microscopic preparation, histological study, automatic image analyzer branches of humerus proximal metaepiphysis were shown to originate from axillary and subscapulary nerves. Nerves and vessels penetrating in the cartilaginous canals form neurovascular complexes. Cartilaginous canals are located unevenly. Nervous structures were found in the canals and their characteristics was given.

Dolores musculoesquéleticos del crecimiento y desarrollo en niños / Growing pains in children

Se tomó una muestra significativa de 100 pacientes de la consulta externa del Servicio de Ortopedia del Hospital Tacuba, ISSSTE, del mes de julio al mes de octubre de 1998 con un rango de edad entre 3 y 12 años. El objetivo era descubrir la existencia del dolor en miembros inferiores, relacionados con el crecimiento y desarrollo, sin patología agregada suponiendo que se debe a un edema subclínico secundario a fatiga por ejercicio físico y demostrar su mejoría rehabilitación específica. Se tomaron estudios radiológicos (AP pelvis, AP y LAT e rodillas, tobillos, dorsoplantar, oblicua y lateral de ambos pies) del segmento afectado, se realizaron exámenes de laboratorio (biometría hemática, velocidad de sedimentación globular, factor reumatoide, proteína C reactiva, exudado faríngeo) y examen físico para descartar datos de otra patología. Posteriormente se entregó un instructivo de ejercicios de estiramiento y adiestramiento a los padres, para la realización de los mismos a los niños con algún problema ortopédico sencillo tal como pie plano, pie cavo, genu valgo o varo fisiológicos y defectos de la marcha, o clínicamente sanos. Se dió seguimiento para valoración de la mejoría. Se encontró que de los 100 pacientes estudiados 60 por ciento presentaban alteraciones ortopédicas. El 47 por ciento requirieron ortosis (zapatos ortopédico, plantillas, separador para Hallux, etc.); 40 por ciento se encontraban clínicamante sanos. Después de los ejercicios de estiramiento se encontró desaparición de los dolores en un 76 por ciento de los pacientes y disminución en la intensidad y frecuencia en el 24 por ciento restante

Immunocytochemical demonstration of pituitary adenylate cyclase activating polypeptide (PACAP) in the porcine epiphyseal cartilage canals.

Pituitary adenylate cyclase activating polypeptide (PACAP), a member of the vasoactive intestinal polypeptide (VIP)/secretin/glucagon family, is known to be a powerful stimulator of adenylate cyclase. Recently, PACAP has been shown to stimulate cAMP in osteoblast-like cells and mouse calvarian bones. In the present study, PACAP immunoreactivity (IR) was demonstrated in cartilage canals from newborn and 3-4-week-old pigs. In tissues from the femoral head and the patella with and without ossification centres, PACAP-IR nerve fibres were found in the cartilage canals innervating blood vessels. The pattern of distribution was not dependent on age or the occurrence of an ossification centre. Co-localization studies showed a high degree of co-localization with calcitonin gene-related peptide (CGRP) and substance P (SP) but little co-localization with VIP. Our findings support earlier findings of CGRP, SP and VIP in bone tissue and add PACAP to the group of neuropeptides with a sensory and/or modulatory function in bone tissue.

Nerves in human epiphyseal uncalcified cartilage.

Increasing evidence demonstrates clinical and neuroendocrine regulation of the skeletal system. We have demonstrated nerve fibers in cartilage canals in human fetal epiphyseal uncalcified cartilage. We investigated specimens from the femur, the proximal tibia, and the humerus from 12 human bodies with an age from the 22nd gestational week to 13 months after birth. We performed Bodian silver staining, Klüver-Barrera staining, and immunostaining for neurofilaments, myelin basic protein. S-100 protein, and vimentin. We observed positive Bodian staining and immunoreaction to neurofilaments in all specimens older than the 30th week of gestational age. Myelin or Schwann cells could not be demonstrated, nor could mechanoreceptors. This indicates a traditional classification as type C nerve fibers with sensory or sympathetic function. In skeletal nerves, an increasing number of neuropeptides influencing bone cells has been detected. The nerves in the cartilage canals may have functions such as regulation of developmental or pathological processes.

Innervation of bone from healthy and arthritic rats by substance P and calcitonin gene related peptide containing sensory fibers.

Mechanical stress causes remodelling of bone, a transformation of bone structure by physical forces through an unknown mechanism. Inflammation also affects bone structure, through altered use and the production of various inflammatory mediators. The peripheral nervous system may play both a sensory and an efferent role in the mechanical and inflammatory influences on bone structure. We studied the occurrence of substance P and calcitonin gene related peptide (CGRP) containing nerves in periosteal tissue, bone marrow, diaphysis and epiphysis of the ankle and knee joints of healthy and adjuvant arthritic rats. In arthritic animals, only ankle joints were affected by the inflammation. The periosteum was richly innervated both in healthy and arthritic animals. In arthritic rats few nerve fibers penetrated the woven, callous bone underlying the periosteum. Also bone marrow contained substance P and CGRP immunoreactive nerves in normal bone, whereas the hypercellular bone marrow of arthritic rats showed a decrease in the density of substance P and CGRP containing fibers. Epiphysis had a dense innervation compared to diaphysis. In contrast to large erosions, small peripheral erosions contained some CGRP immunoreactive fibers, perhaps as a sign of attempts of reactive repair. Our results suggest a local delivery system of potent peptide regulatory factors in bone, a system also affected by the pathophysiology of arthritis.