Nacre initiates biomineralization by human osteoblasts maintained in vitro

When nacreous shell produced by the marine oyster Pinctada maxima, used as a biomaterial in oral surgery, is implanted in human bone, new bone formation occurs, resulting in a tight welding of the bone to the nacre [16]. These findings are consistent with the possibility that nacre adjacent to bone can locally stimulate osteogenic activity. To test this hypothesis, we have evaluated the effect of the simultaneous presence of bone and nacre on human osteoblasts in vitro. Nacre chips (1 mm3) were placed at approximately 1 mm distance from a similarly sized bone chip on a layer of first passage human osteoblasts. None of the chemical inducers generally required to obtain bone mineralization in vitro (in particular, beta-glycerophosphate) was added to the cultures. Mineralized sections of the cultures were evaluated by light and electron microscopy, contact microradiography, and Laser Raman Spectroscopy. The results demonstrated that nacre has strong osteogenic effects on human osteoblasts when placed in proximity to bone in vitro. New bone formation occurred by both appositional growth on the existing bone and by the formation of mineralized nodules within the matrix adjacent to the bone explant. Electron microscopic evaluation of these sites demonstrated findings typical of those described in the course of bone formation in vivo, and no evidence of toxicity was observed. In addition, under the conditions of culture used, nacre can also promote the formation by osteoblasts of a structure with characteristics similar to nacre (e.g., lamellar organic matrix mineralized with aragonite, as demonstrated by Laser Raman Spectroscopy).(ABSTRACT TRUNCATED AT 250 WORDS)

Kirkpatrick-Baez microscope based on a Bragg-Fresnel x-ray multilayer focusing system

We demonstrate how to use a cylindrical Bragg-Fresnel multilayer focusing system instead of spherical mirrors for two-dimensional focalization. We performed our tests at 8 keV with a collimated x-ray tube having an apparent anode source size of 75 microm x 100 microm. These tests demonstrate that focalization can be obtained within <20 microm. This offers new possibilities in optical systems for collimators and fine focusing of x-rays, especially for synchrotron radiation sources.

Demonstration of the capacity of nacre to induce bone formation by human osteoblasts maintained in vitro

Nacre implanted in vivo in bone is osteogenic suggesting that it may possess factor(s) which stimulate bone formation. The present study was undertaken to test the hypothesis that nacre can induce mineralization by human osteoblasts in vitro. Nacre chips were placed on a layer of first passage human osteoblasts. None of the chemical inducers generally required to obtain bone formation in vitro was added to the cultures. Osteoblasts proliferated and were clearly attracted by nacre chips to which they attached. Induction of mineralization appeared preferentially in bundles of osteoblasts surrounding the nacre chips. Three-dimensional nodules were formed by a dense osteoid matrix with cuboidal osteoblasts at the periphery and osteocytic-like cells in the center. These nodules contained foci with features of mineralized structures and bone-like structures, both radiodense to X-ray. Active osteoblasts (e.m.) with abundant rough endoplasmic reticulum, extrusion of collagen fibrils and budding of vesicles were observed. Matrix vesicles induced mineral deposition. Extracellular collagen fibrils appeared cross-banded and electrodense indicating mineralization. These results demonstrate that a complete sequence of bone formation is reproduced when human osteoblasts are cultured in the presence of nacre. This model provides a new approach to study the steps of osteoblastic differentiation and the mechanisms of induction of mineralization.

[Automatic voice recognition for radiologic reports. Experiment with a prototype in an operational environment]

Large vocabulary speech recognition, its techniques and its software and hardware technology, are being developed, aimed at providing the office user with a tool that could significantly improve both quantity and quality of his work: the dictation machine, which allows memos and documents to be input using voice and a microphone instead of fingers and a keyboard. The IBM Rome Science Center, together with the IBM Research Division, has built a prototype recognizer that accepts sentences in natural language from a 20,000-word Italian vocabulary. The unit runs on a personal computer equipped with a special hardware capable of giving all the necessary computing power. The first laboratory experiments yielded very interesting results and pointed out such system characteristics to make its use possible in operational environments. To this purpose, the dictation of medical reports was considered as a suitable application. In cooperation with the 2nd Radiology Department of S. Maria della Misericordia Hospital (Udine, Italy), a system was experimented by radiology department doctors during their everyday work. The doctors were able to directly dictate their reports to the unit. The text appeared immediately on the screen, and eventual errors could be corrected either by voice or by using the keyboard. At the end of report dictation, the doctors could both print and archive the text. The report could also be forwarded to hospital information system, when the latter was available. Our results have been very encouraging: the system proved to be robust, simple to use, and accurate (over 95% average recognition rate). The experiment was precious for suggestions and comments, and its results are useful for system evolution towards improved system management and efficiency.

Geometry of Some Strained Oxygen Ring Compounds: 1,3-Benzodioxole and 2,3-Dihydro-1,4-benzodioxin (Benzodioxan). Application to the Geometry of (6aR-cis)-3-Methoxy-6a,12a-dihydro-6h-[1,3]dioxolo-[5,6]benzofuro[3,2-C] [1]benzopyran (Pterocarpin)

The geometry of benzodioxole, benzodioxan and the strained five- membered rings of pterocarpin are studied by the MNDO method. We show that in benzodioxole there is bond alternation towards a Kekule -like structure such as in indan (Mills-Nixon effect). In benzodioxole, owing to the smaller perimeter of the fused ring and enhanced strain, alternation is more pronounced than in indan . An explanation is offered for the strong distortion in ring angles in benzodioxole compared with indan. The effect of strain in benzodioxan and pterocarpin is discussed.

Co-localization and secretion of parathyrin of Stannius corpuscles (immunoreactive parathyroid hormone) and of secretory glycoproteins including secretory protein-I in the European eel (Anguilla anguilla L.)

Until recently, teleosts were considered to be devoid of parathyroids. We showed recently that the corpuscles of Stannius, that structurally have features in common with the parathyroid gland, produce a molecule resembling mammalian parathyroid hormone (PTH). We refer to this molecule as parathyrin of corpuscles of Stannius (PCS). Parathyroid secretory protein-I (SP-I) is an acidic glycoprotein, probably identical to adrenal chromogranin A, that is co-stored and co-secreted with PTH. In the present study, PCS was localized in secretory granules of fresh water eels by immunocytochemistry. In addition, several glycoproteins were identified in these granules by periodic acid-Schiff staining and/or concanavalin A lectin binding. One of the glycoproteins that was positive with periodic acid-Schiff, but not with concanavalin A, cross-reacted with antisera to bovine parathyroid secretory protein-I. When the eels were made hypercalcemic by injecting calcium or pituitary extract, there was a coincidental translocation of the PCS, immunoreactive SP-I and the glycoproteins, suggestive that these granules were undergoing exocytosis. Immunoblot analysis of saline extract of the corpuscles of Stannius confirmed that immunoreactive SP-I was present in the tissue. It exhibited a molecular mass of about 55 kDa compared to about 70-80 kDa exhibited by mammalian SP-I when analyzed by sodium dodecylsulfate-polyacrylamide gel electrophoresis.

[Tricuspid endocarditis. Value of echocardiography. Developmental data. Apropos of 11 cases]

Clinical and echocardiographic data of 11 patients with tricuspid valve endocarditis (TE) were analysed to determine diagnostic criteria and to study the outcome of this condition. The study population comprised 6 men and 5 women (average age 38.4 +/- 18 years). TE was the only lesion in 9 cases; there was 1 case of associated pulmonary and aortic valve endocarditis, and in the other patient mitral and aortic valve endocarditis was also present. Five patients were heroin addicts. In 5 cases, the causative organism was Staphylococcus aureus. The clinical presentation was usually atypical with a systolic murmur rarely characteristic in 9 patients and signs of right ventricular failure in only 3 patients. On the other hand, 8 patients had one or more episodes of acute pneumonia or typical pulmonary embolism. The diagnosis was established by echocardiography which demonstrated the valvular vegetations. The outcome was favourable in 10 patients, only one of whom required surgical intervention. Two dimensional echocardiography provided valuable information about the evolution of the valvular vegetations, frequently showing regression after medical therapy.

Immunocytochemical detection in eel corpuscles of Stannius of a mammalian parathyroid-like hormone

Stannius corpuscles of the eel synthesize and secrete a mammalian parathyroid-like hormone called parathyrin of CS (PCS). PCS has been localized in the cytoplasm of all cells in the corpuscles, detection being by indirect immunofluorescence with an antiserum anti-1-84 bovine hormone (PTH). The specificity of the reaction was demonstrated by inhibition of the fluorescent staining with 1-84 bovine PTH and the active fragment 1-34 of human PTH. Variations of the cellular localization of the PCS or a complete depletion of the hormonal content, in all cells, were observed in eels made hypercalcemic by Ca overloading. The secretory activity of the two types of CS cells may be regulated by the plasma Ca2+ concentration.

Evidence for the presence of osseous tissue in dogfish vertebrae

The calcified cartilage of the dogfish vertebra has been studied by means of an undecalcified hard tissue method, including microradiography and tetracycline labelling, and electron microscopy. The transversely sectioned vertebra shows a centrum and neural and hemal arches. The mineralized area consists of a narrow but continuous band, which touches the perichondrium, and is formed by chondrocytes that participate in the mineralizaton of the surrounding matrix. The neural arches appear quite different; the upper parts contain an hypertrophied cartilage and, close to it, an inner zone formed by crescent shaped lamellar bone tissue containing osteoblasts and osteocytes. Tetracycline labelling of these two types of hard tissue reveals a globular calcification with calcospherites and Liesegang rings, at the level of the calcified cartilage, and a strong and linear label of the inner border of the osseous tissue. Transmission electron microscopy shows Type I collagen in the crescent shape area and Type II collagen in calcified cartilage area. The presence of osseous tissue in elasmobranch endoskeleton is discussed in relation to the evolution of the gnathostomes skeleton and the endocrinological control of calcium metabolism.

[Immunocytochemical detection in Stannius corpuscles of the eel (Anguilla anguilla L.) of a hormone similar to the mammalian parathyroid hormone]

In eels the parathyrin of the corpuscles of Stannius (PCS), mammalian parathyroid-like hormone, has been localized in the cytoplasm of all the cells in the corpuscles. This detection was done by indirect immunofluorescence with an antiserum anti 1-84 bovine parathormone. The specificity of the reaction was demonstrated by inhibition of the coloration obtained with the 1-84 bovine parathormone and the active fragment 1-34 of human parathormone. Variations of the cellular localization of the PCS or a complete depletion of the hormonal content were observed in eels made hypercalcaemic by calcium overloading.

[Demonstration of bone tissue in the axial skeleton of a chondrichthian: the dogfish (Scyliorhinus canicula)]

Dogfish vertebra have been studied by means of an undecalcified hard tissue method, including microradiography and tetracycline labelling. The transversal section of Dogfish vertebra shows a centrum and two couples of neural and hemal arches. The mineralized area consists of a narrow but continuous band, just against the perichondrium, formed by chondrocytes that participate in the surrounding matrix mineralization. The neural arches appear quite different: the upper parts contain hypertrophied cartilage and, close to it, the inner zones are formed by a crescent-shaped lamellar bone containing osteoblasts and osteocytes. A tetracycline label of these two types of hard tissue reveals a globular calcification with calcospherites and Liesegang rings, at the level of calcified cartilage and a strong and linear label of the inner border of the osseous tissue. The presence of osseous tissue in Elasmobranch endoskeleton is discussed in relation to, on one hand the evolution of the Gnathostomes skeleton and on an other hand the endocrinological point of view of calcium metabolism regulation in this group.

[The phalanges. Notes on the radiographic semeiology of osseous metabolism]

The hand, and the phalanges in particular, offer a privileged observation ground for the study of some features of bone metabolism. An account is given of the cell alterations from which the various disturbances associated with osteogenesis and osteolysis can be recognized, particular attention being devoted to changes in bone density, cortex thickness, and the structure of the spongy substance. Evaluation of these three parameters will lead to the recognition of porosis, malacia, hyperosteolysis, and osteomyelosclerosis. When combined with certain clinical and laboratory data, the findings can readily be used to reach an exact diagnosis.

Liver storage iron in normal population of Cuba

One hundred sixty-one liver specimens from subjects who died acute traumatic deaths were studied. Of these, 127 came from male subjects and 34 from female subjects. The liver storage iron values of subjects in the persent study dying acutely from traumas and the differences found are in agreement with those expected according to the iron physiological needs and the prevalence of anemia reported by this cause in the world. This substantiates that the study of nonheme iron contents in subjects who died acute traumatic deaths is a good method for assessing iron nutritional status in a population. It is interesting to note the significant increase of hepatic storage iron found in men 61 to 70 years old, although it would be important to increase the number of cases to obtain more representative data. Liver storage iron in the Cuban population is not essentially different from that reported in the United States, Sweden, and Australia and the deficiency percentage is one of the lowest in Latin America.

Paradoxical effect of 1,25 dihydroxycholecalciferol on osteoblastic and osteoclastic activity in the skeleton of the eel Anguilla anguilla L

Female mature eels (300 to 500 g) received one intraperitoneal injection of 1.25(OH)2D3 (10 microgram). Their vertebral bone was compared, 8 h and 24 h after the injection, with vertebral bone of control mature female eels receiving solvent alone (ethanol). Sexual maturation in female eels induces a bone decalcification with hypercalcaemia and hyperphosphataemia. The control eels showed marked osteoclastic resorption and osteocytic osteolysis and the degree of mineralization of the intercellular substance decreased. Injection of 1.25 (OH)2D3 into these female mature eels provoked as early as 8 h: 1) an increase in hypercalcaemia and hyperphosphataemia; 2) a major conversion of lining cells to osteoblasts and a stimulation of osteoblastic activity with new bone formation; 3) diminished osteoclastic resorption without changing osteocytic osteolysis or bone matrix mineralization.

[Unilateral alveolar effusions (author's transl)]

The unilateral alveolar effusions can be divided into two groups: those which take place in an already diseased lung (ipsilateral), and those which take place in the healthy one (contralateral). Starting from the most recent literature, the causes of the two different radiological features are discussed. Some cases of alveolar effusions, both ipsilateral and contralateral, are reported.

Nonquarterwave multilayer filters: optical monitoring with a minicomputer allowing correction of thickness errors

Many spectral filtering problems require assemblies of layers having thicknesses that bear no obvious relationship to one another. After a brief review of the optical methods used to monitor deposition of multilayers containing nonintegral thicknesses, we show that the performance of monitoring systems can be improved further by including the real-time calculation of any necessary layer thickness changes that may be required to compensate any errors that might still occur. The apparatus described consists of a minicomputer coupled to a rapid-scanning spectrometer. Such a procedure working in real time avoids the cumulative effects of successive errors. The technique is demonstrated in the production of a beam splitter.

Wideband optical monitoring of nonquarterwave multilayer filters

The construction of optical filters, which are required to have optical properties well defined over wide spectral regions, demands the use of multilayer designs in which there are no simple relationships between the thicknesses of the layers. There are considerable difficulties in the manufacture of such multilayers. First, we must be able to reproduce, sufficiently accurately, the indices of refraction that have been used in the theoretical design. Then we must be able to control the optical thicknesses of each layer, which necessitates measurement of the optical properties of the multilayer during deposition. The apparatus described consists of a minicomputer coupled to a rapid-scanning spectrometer that continuously measures the spectral profile during deposition of each layer. The precise measurement of the evolution of the optical properties during actual construction of a filter allows us to control layer thickness with very good accuracy. The technique is demonstrated in the monitoring of a beam splitter made of a few layers.

Optical monitoring of nonquarterwave multilayer filters

Many spectral filtering problems require the use of assemblies of layers having thicknesses which bear no obvious relationship to each other. Successful production of these multilayers requires films with thicknesses approximating theoretical values. We show that the optical methods currently used in the production of film assemblies of quarterwave layer thicknesses, which are based on the use of just one single wavelength, are poorly adapted to monitoring the deposition of nonintegral thickness multilayers. In contrast we show that with an optical control system utilizing a broad spectral bandwidth, thickness errors can be reduced. Transmittance measurements with the precision necessary to achieve this improved thickness control are attainable with existing instrumentation. This result is established by a computer simulation of the construction of a specific multilayer and remains valid for other nonquarterwave multilayer filters.