Ex vivo high resolution MR imaging of the human lip with a dedicated low field system.

Histological correlations of the human lip with corresponding magnetic resonance (MR) images obtained ex vivo are presented. MR images were acquired with a dedicated low-field (0.1 T) MR system, with a resolution of 100 x 100 micron2 and a slice thickness of 1 mm using 3D-FLASH sequences. The outermost tissues visible on images are of high signal intensity, while the innermost connective tissues are of low signal intensity, both for skin and oral mucosa. It is possible to use a low-field system to obtain high resolution images of small biological samples.

Microvascularisation of the lips in the fetus and neonate.

The differences observed in the microvascularisation of the lips in the perinatal period correspond to the differences in the histological structures of the cutaneous, glabra, intermediate cutaneous, villous, intermediate mucosal and mucosal parts. A basic pattern is found in each part: on the surface, a papillary or mucosal network, at a deeper level, reticular or submucosal networks and their pedicles. The vascular changes correspond to the transition of tissue (mucocutaneous junction) and are indicative of the functional aspect. The same histological and microcirculatory structures were found in all the preparations, irrespective of the subject's age. Knowledge of the microvascularisation makes it possible to interpret magnetic resonance imaging of the lip better and finds its application in the surgery of the lips.

Vascular networks of the periphery of the fingernail.

The vascular networks of the periphery of the fingernail have been studied on fingers of adults, foetuses and neonates, by injecting the vascular system with gelatinous Indian ink. The nail is an avascular structure, partially covered by the nail wall. It is lying on the nail bed which is prolonged forwards with the hyponychium. Each part of the nail apparatus presents a characteristic vascular network derived from dorsal collaterals arising from the palmar digital vessels and from their arcades. These networks are papillary, pseudopapillary, reticular and subdermal. Their morphology and density vary according to their localization and correspond with histological variations of the different parts of the nail apparatus. Thus, the germinal part of the nail bed shows poor vascularization. It is responsible for the colour of the lunula. The sterile part and the hyponychium have dense vascular networks with glomus bodies.

[Extra-osseous and intra-osseous microvascularization of the sternum of the child]. / La microvascularisation extra-osseuse et intra-osseuse du sternum de l'enfant.

The microvascularization of the sternum of the child has been studied by a method of India ink injection and by histology. Extra-osseous vasculature includes vascular pedicles and sternal vascular networks. Vascular anterior and posterior pedicles issue from internal mammary vessels. Sternal anterior and posterior networks are disposed on the faces of the sternum and are divided in a superficial one and a deep one; both are included in the perichondrium. In newborns and in young infants, vascular structures looking like baskets are affixed to the deep sternal network. It is unlikely that they intervene in the constitution of the adult pattern of the sternal vasculature. The early complete development of sternal networks contrasts with the existence of evolutive characteristics of the intra-osseous vasculature. Intra-osseous vasculature includes the cartilage canal vessels and the vessels of the ossification centers. Cartilage canals are provided with an axial artery, issued from the deep sternal network, which produces short capillaries which continue in peripheral sinuses. Cartilage canals permit the penetration of perichondral tissue deep in the cartilage of the developing sternum, allowing the formation of the ossification center. The ossification center is vascularized by centrifugal arteries, issued from the cartilage canal artery, and disposed in a radiant pattern. They continue, through a conical progressive dilatation, into a sinusoid network, which presents a convergent disposition towards the center of the ossification point. Vascular events precede ossification. Hematopoietic development is consecutive to the vascular events too. The slenderness of vascular pedicles contrasts in neonates with the wide development of the sinusoid network. Adipose tissue is rare in the bone marrow sternum of the child. Secondary evolution of the ossification center vasculature permits its connections with the deep sternal vascular network, with adjacent cartilage canals, and with adjacent ossification centers. Progressively, the number and the importance of the peripheral pedicles of the ossification centers increase. Thus, a multiple and centripetal vascular provision takes the place of the initial, unique, centrifugal one. These modifications correspond to the transition from the vascular pattern of an expanding structure (the ossification center) to the one which is adapted to the full expression of its hematopoietic function.

Continuous gas-depletion technique for measuring O2-dissociation curves of high-affinity hemoglobins.

The O2-depletion technique allows a continuous measurement of the complete O2-dissociation curve of high-affinity hemoglobins in the O2-partial pressure range of 700 to 10(-4) mm Hg. With this technique p50 values greater than or equal to 0.01 mm Hg (approximately equal to 1.3 Pa) can be determined for 3-microliter hemoglobin samples. As examples, O2-dissociation curves of sperm whale myoglobin (p50 = 0.9 mm Hg, 25 degrees C, pH 8.0) and Dicrocoelium hemoglobin (p50 = 0.06 mm Hg, 25 degrees C, pH 4.9) are demonstrated which show Hill coefficients of n = 1.0 over the complete O2-saturation range.

Co-binding studies on Hb M Iwate. Allostery of a T state haemoglobin.

The mutant haemoglobin Hb M Iwate alpha 2Mmet87His leads to Tyr beta 2, is characterized by a stable T structure and a low ligand affinity. Sigmoidal CO-binding isotherms of symmetrical shape with Hill coefficients of n = 1.4 at pH 6 to n = 1.9 at pH 10 and the differences in the mean affinity (PCO(1/2)) and the affinity of the first ligand-binding beta subunit (1/L1 greater than Pco(1/2)) are the evidence for the cooperativity. The comparison of the Bohr effects of the two valency hybrid states (alpha 2Mmet beta met beta deoxy alpha 2Mmet beta 2deoxy) in the absence of and in the presence of polyphosphates leads to an indirect proof of pH-dependent subunit-subunit interaction. Inositol hexaphosphate-binding suppresses cooperativity in the pH range 5.5-8 (n = 1). Above pH 8 hte cooperativity increases to a final value of n = 1.9 at pH greater than 10, which is identical to that of stripped Hb M Iwate. The CO binding to the first binding site exhibits a Bohr effect. Polyphosphate anions have no influence on the CO binding of the first binding site. The heterotropic effects are discussed as intrachain effects (Bohr effect of the first binding site) and interchain effects (Bohr effect of Pco(1/2); influence of polyphosphates).

Bone marrow necrosis. acute microcirculation failure in myelomonocytic leukemia.

We saw bone marrow necrosis in a case of acute myelomonocytic leukemia. The diagnosis was made during the patinet's life, and the bone marrow microcirculation was studied immediately postmortem. Histology and injection of the bone marrow arteries showed an acute microcirculation failure. The pathogenesis and possible relationship with soluble immune complexes was studied.

[Comparative study of the regeneration of the microcirculation of rabbit femur bone marrow after curetage and at the time of experimental myelosclerosis]. / Etude comparative de la regénération de la microvascularisation de la moelle osseuse du fémur de lapin après curetage et lors de la myélosclérose expérimentale.

Destruction and regeneration of the bone marrow microcirculation in rabbit femur have been studied after curetage and experimental myelosclerosis. Different lesions lead to comparable restoration processes such as: installation of supplying vascular networks, appearance of a neovascularisation progressively replaced by neighboring structures of normal interadipocytic networks.

[Medullary microcirculation in human primary and secondary myeloscloroses]. / La microcirculation médullaire au cours des myéloscléroses humaines primitives et secondaires

There are histological and experimental evidence for bone marrow microcirculation to play a role in histogenesis of myelosclerosis. Human sternal bone marrow microcirculation was studied after death using ink injection in two cases of primary myelofibrosis, two cases of secondary meylofibrosis (Hodgkin's disease) an one case of osteomyelosclerosis. Control material consisted of 30 previously studied normal human sternums. In all cases interadipocytic sinusoidal network has completely disappeared. Medullary vascularization is anarchic with a vascular and hypervascular areas. The significance of these modifications is discussed.

[Vascular regeneration of rabbit femoral bone marrow after curettage (author's transl)]. / La régénération de la vascularisation de la moelle osseuse du fémur de lapin après curetage

The curettage of a section of bone marrow in rabbit femur entails the destruction of the corresponding vascularization. Starting on the first day the undistroyed interadipocytic network is widely open. It is fed: 1. via those branches of the nutrient artery that stay connected; 2. via branches of the nutrient artery that become disconnected and then form anastomosis with the epiphysial arteries or compact bone arteries and thus become revascularized; 3. via the arteries vascularizing compact bone. By the thirds of fourth day after intervention, both poles of the hematoma are lined by vascular caps. This is composed of a rich network neo-vessels showing three distinct levels. After four or five weeks these networks will have come together and anastomosed. Between the hematoma and the compact bone tissue large vascular lacunae are formed. They receive blood from the arteries of the compact bone. The vascular networks drain into the veins of diaphyseal compact bone or are drained via intact vestiges of the central venous sinus. In those areas where the hematoma is reabsorbed, a partially reconstructed vascular tree appears. Peripheral longitudinal arteries send out centripetal rami towards the central vascular buds as well as centrifugal rami towards subcortical vascular buds. The interdipocytic network also regains its normal morphology. The central venous sinus extends from one epiphysis to the other and is usually drained into the veins of the trochanteric fossa proximally and into the popliteal veins and supra-trochlear veins distally.