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PubMed1988

Protein adsorption at the interface between charged polymer substrata and migrating osteoblasts.

The in vitro migratory morphology of neonate rat calvarial osteoblasts on positively or negatively-charged polymer substrata was observed using scanning (SEM) and transmission electron microscopy (TEM). Proteins adsorbed from the culture medium onto these charged substrata were desorbed using 2% SDS and separated using polyacrylamide gel electrophoresis (PAGE). The charge sign of the substrata affected both protein adsorption and osteoblast migratory morphology. Cells flattened and adapted so closely to positively-charged substrata that the ventral cell membrane could not be distinguished at TEM. On negatively-charged substrata the ventral cell membrane was readily visible, with only focal areas of close contact with the substratum. The depth of the ventral extracellular space varied with the surface charge-carrier species on the negative substrata. Two desorbed protein fractions (MW 220 and 30 kDaltons, respectively) were correlated with osteoblast spreading on positive and negatively-charged surfaces respectively. Another protein fraction was uniquely present on PAGE profiles desorbed from negatively-charged substrata. It was concluded that the migratory morphology of osteoblasts was influenced via the intermediary of specifically adsorbed proteins.

Adsorption↗
PubMed2004

Thin film MRI-high resolution depth imaging with a local surface coil and spin echo SPI.

A multiple echo, single point imaging technique, employing a local surface coil probe, is presented for examination of thin film samples. Depth images with a nominal resolution of 5 microm were acquired with acquisition times on the order of 10 min. The method may be used to observe dynamic phenomenon such as polymerization, wetting, and drying in thin film samples. It is readily adapted to spatially resolved diffusion coefficient and T2 relaxation time mapping.

Algorithms↗
PubMed2004

Tensile and compressive behaviour of the bovine periodontal ligament.

The mechanical response of the bovine periodontal ligament (PDL) subjected to uniaxial tension and compression is reported. Several sections normal to the longitudinal axis of bovine incisors and molars were extracted from different depths. Specimens with dimensions 10 x 5 x 2 mm including dentine, PDL and alveolar bone were obtained from these sections. Scanning electron microscopy suggested a strong similarity between the bovine PDL and the human PDL microstructure described in the literature. The prepared specimens were tested in a custom made uniaxial testing machine. They were clamped on their bone and dentine extremities and immersed in a saline solution at 37 degrees C. Stress-strain curves indicated that the PDL is characterized by a non-linear and time-dependent mechanical behaviour with the typical features of collagenous soft tissues. The curves exhibited hysteresis and preconditioning effects. The mechanical parameters evaluated in tension were maximum tangent modulus, strength, maximizer strain and strain energy density. For the molars, all these parameters increased with depth except for the apical region. For the incisors, all parameters increased with depth except ultimate strain which decreased. It was assumed that collagen fibre density and orientation were responsible for these findings.

Adaptation, Physiological↗
PubMed1997

The new Italian code of medical ethics.

In June 1995, the Italian code of medical ethics was revised in order that its principles should reflect the ever-changing relationship between the medical profession and society and between physicians and patients. The updated code is also a response to new ethical problems created by scientific progress; the discussion of such problems often shows up a need for better understanding on the part of the medical profession itself. Medical deontology is defined as the discipline for the study of norms of conduct for the health care professions, including moral and legal norms as well as those pertaining more strictly to professional performance. The aim of deontology is therefore, the in-depth investigation and revision of the code of medical ethics. It is in the light of this conceptual definition that one should interpret a review of the different codes which have attempted, throughout the various periods of Italy's recent history, to adapt ethical norms to particular social and health care climates.

Advisory Committees↗
PubMedDate not supplied

Sexuality after spinal cord injury: the Greek male's perspective.

OBJECTIVE: This study explored how Greek men with spinal cord injury experience sexuality. METHODS: Six men with spinal cord injury acted as key informants and data collection consisted of in-depth unstructured interviews, field notes, and a reflective log. The transcribed interviews were analyzed thematically. RESULTS: The themes that emerged were: Barriers, Metamorphoses, and Enjoying. Sexuality was important in the life of the informants and they were engaged in various patterns of adaptation. Rather than impairment as such, certain social beliefs and values prevalent in Greek society were found to act upon the informants in compromising ways. CONCLUSION: The results suggest that the process of reclaiming one's sexuality is a process of meaning-finding. The data support a conclusion that occupational therapists should respect the cultural nature of sexuality. Moreover, the topic of sexuality should be approached in a holistic manner, perceiving it as extending in a continuum, which may be positively or negatively affected as a result of an acquired impairment.

Adult↗
PubMed2000

[Standards, Options and Recommendations (SOR) for the surveillance and the prevention of cross infections in oncology. Fédération Nationale des Centres de Lutte Contre le Cancer].

CONTEXT: The "Standards, Options and Recommendations" (SOR) project, started in 1993, is a collaboration between the Federation of the French Cancer Centres (FNCLCC), the 20 French Cancer Centres and specialists from French Public Universities, General Hospitals and Private Clinics. The main objective is the development of clinical practice guidelines to improve the quality of health care and outcome for cancer patients. The methodology is based on literature review and critical appraisal by a multidisciplinary group of experts, with feedback from specialists in cancer care delivery. OBJECTIVES: To develop clinical practice guidelines according to the definitions of the Standards, Options and Recommendations project for the prevention and the surveillance of cross infection in oncology. METHODS: Data were identified by searching Medline and the personal reference lists of members of the expert groups. Once the guidelines were defined, the document was submitted for review to 106 independent reviewers, and to the medical committees of the 20 French Cancer Centres. RESULTS: 1) Criteria of infection status and nosocomiality defined by the Centers for Infectious Diseases (CDC) and Prevention and the Superior Council of Public Hygiene (CSHPF) are not adapted and have to be redefined in oncology. 2) The epidemiology of nosocomial infections in oncology is not well known but their incidence seems to be higher. Numerous risk factors of cross infections coexist in cancer patients, among which the duration and depth of neutropenia. 3) Surveillance and prevention of cross infection are compulsory and were taken into account in the accreditation of hospitals. Obligation is expressed in terms of means and results. 4) The objectives of the cross infection surveillance are to detect major problems and critic situations, to guide probabilistic antibiotic therapy and to assess the effectiveness of the infections control. The surveillance means consist in prevalence and incidence survey, punctually and continuously conducted. 5) The three specific behaviors to be adopted to prevent cross infections are to control: all the patients, infected patients carrying multiresistant bacteria, immunodepressed patients. 6) Standards of care have to be applied to a/l patients with cancer. 7) It is necessary to add particular septic cares for the patients infected with micro-organisms indicated on reference lists or carrying multiresistant bacteria. 8) The only objective of the protective isolation of immunodepressed cancer patients is to reduce the cross infection. There is no standard behavior for the indications and the modalities of protective isolation. The prevention behaviors to be taken are defined by expert agreements.

Algorithms↗
PubMedDate not supplied

In situ lactate dehydrogenase patterns as markers of tumour oxygenation.

The histochemical patterns of lactate dehydrogenase, LDH, are here proposed as indicators of the local levels of oxygenation of malignant tissue. This parameter has outstanding importance in determining the tumour aggressiveness and response to treatment. The tetrazolium salt reaction previously proposed for the mapping of hypoxia has been improved by the use of polyvinyl alcohol as a tissue stabilizer. The intracellular coloured products of this reaction appear in two distinct forms, diffuse and granular, which we previously postulated to be indicative of LDH isoenzymes soluble and bound, respectively. Solubility is promoted by H-LDH subunits preferentially synthesized under good oxygenation; binding to membranes is favoured by the presence of M-LDH subunits preferentially active under poor oxygeneration. A reversible shift between the two forms apparently regulates the cells' metabolic adaptation to different stress situations. We assume that the anoxic shock protein LDHk exists exclusively in the bound form. In the Ehrlich carcinoma model previously employed, we verify a drift towards the exclusive presence of the granular form as the section's depth increases and/or when the cuff width decreases. This trend is ascribed to a progressive worsening of the local oxygenation levels. At the tumour interface, a chronic inflammatory tissue (notoriously highly hypoxic) is characterized by a granular LDH activity. New models of hypoxia are proposed and discussed for explaining the patterns here described and observed also in other studies, namely those derived from hyperviscosaemia, damaged endothelia, fibrosis, anaemia, poor ventilation and impaired cardio-vascular system.

Animals↗
PubMed1976

Exercise tolerance at 4 and 6 ATA.

Seven normal male subjects performed 5-min bicycle exercise ranging from 50-100% maximum oxygen uptake at 4 ATA and three were also studied at 6 ATA. At all pressures, the subjects breathed 0.2 ATA O2 plus nitrogen. All subjects were able to perform maximum work at all pressures. No pressure-dependent variations in heart rate, O2 uptake, or CO2 output were noted. At both 4 and 6 ATA, ventilation was decreased at exercise levels greater than 80% maximum O2 uptake. The magnitude of the decrease was not great, however, and signified only minor CO2 retention. In some instances exercise ventilation closely approached the 15-S maximum breathing capacity and these subjects noted severe dyspnea, possibly due to dynamic compression of large airways. In three subjects, respiratory frequency was measured as well as minute ventilation; this relationship did not change with depth. Subjects performing heavy exercise at 6 ATA noted disturbances of consciousness, presumably due to N2 narcosis.

Adaptation, Physiological↗
PubMed1999

Developing a culture of lifelong learning in a library environment.

Between 1995 and 1996, the Annette and Irwin Eskind Biomedical Library (EBL) at Vanderbilt University Medical Center (VUMC) radically revised the model of service it provides to the VUMC community. An in-depth training program was developed for librarians, who began to migrate to clinical settings and establish clinical librarianship and information brokerage services beyond the library's walls. To ensure that excellent service would continue within the library, EBL's training program was adapted for library assistants, providing them with access to information about a wide variety of work roles and processes over a four to eight-month training period. Concurrently, customer service areas were reorganized so that any question--whether reference or circulation--could be answered at any of four service points, eliminating the practice of passing customers from person to person between the reference and circulation desks. To provide an incentive for highly trained library assistants to remain at EBL, management and library assistants worked together to redesign the career pathway based on defined stages of achievement, self-directed participation in library-wide projects, and demonstrated commitment to lifelong learning. Education and training were the fundamental principles at the center of all this activity.

Career Mobility↗
PubMed2001

[Quantitative 3D anatomy of the lumbar spine].

PURPOSE OF THE STUDY: There are many anatomic descriptions of the spine, but most concentrate on qualitative information. Quantitative data is however important to achieve a better clinical approach, to adapt implant size and to construct geometric models of spine mechanics. MATERIAL AND METHODS: We examined 32 dry spines (160 lumbar vertebrae) obtained from the Orfila Museum anatomy laboratory at the Saints-Pères School of Medicine in Paris. We drew 178 landmarks on the surface of each vertebra and recorded the 3D spatial coordinates of each point using a Fastrack electromagnetic system operating with +/- 0.2 mm precision. The coordinates of the digitalized points were expressed in a local x-y-z axis field (x=posteroanterior axis, y=right-left axis, z=caudocranial axis). The origin O was half way between the "centers" of the vertebral plates. After calculating 112 linear, angular and surface parameters, results were analyzed with the Statview statistics system. RESULTS: All parameters exhibited gaussian distribution. The transpedicular vertebral depth, corresponding to the maximal penetration of a pedicular screw before touching the anterior wall, was nearly constant: 48 mm (mean). The mean height of the pedicle was approximately 16 mm for L1 to L4 and 21 mm for L5. Pedicle width was 7 mm for L1 and L2 then rapidly widened to reach 10 mm for L5. It was noteworthy that the narrowest pedicle (4 mm) was found in 10% of the L1 vertebrae. There was an exponential rise in the sagittal tilt of the pedicles from L1 to L5, measuring approximately 8 degrees for L1 and rising to 24 degrees for L5. DISCUSSION: Our sample of human spines with unknown clinical characteristics (age, sex) is representative of anatomy laboratory populations, generally composed of subjects over 40 years of age, and is thus adapted for studies of the degenerative spine. Our findings are generally in agreement with data reported in the literature and also provided complementary quantitative data concerning the transpedicular vertebral depth that was found to be a rather constant feature of the lumbar spine. It measured between 40 and 56 mm for 95% of the study population. The dimensions of the pedicle is particularly important: the width must be known to determine the size of pedicle screws; it measured between 7 and 12 mm in 95% of the population. The largest mean cross section of the pedicle was found for L5 (82mm(2)), but measured less than 60 mm(2) in 10% of the vertebrae, suggesting predisposition to spondylolysis.

Anthropometry↗
PubMed2002

Preparative two-dimensional gel electrophoresis at alkaline pH using narrow range immobilized pH gradients.

A reproducible high-resolution protein separation method is the basis for a successful differential proteome analysis. Of the techniques currently available, two-dimensional gel electrophoresis is most widely used, because of its robustness under various experimental conditions. With the introduction of narrow range immobilized pH gradient (IPG) strips (also referred to as ultra-zoom gels) in the first dimension, the depth of analysis, i.e. the number of proteins that can be resolved, has increased substantially. However, for poorly understood reasons isoelectric focusing on ultra-zoom gels in the alkaline region above pH 7 has suffered from problems with resolution and reproducibility. To tackle these difficulties we have optimized the separation of semipreparative amounts of proteins on alkaline IPG strips by focusing on two important phenomena: counteracting water transport during isoelectric focusing and migration of dithiothreitol (DTT) in alkaline pH gradients. The first problem was alleviated by the addition of glycerol and isopropanol to the focusing medium, leading to a significant improvement in the resolution above pH 7. Even better results were obtained by the introduction of excess of the reducing agent DTT at the cathode. With these adaptations together with an optimized composition of the IPG strip, separation efficiency in the pH 6.2-8.2 range is now comparable to the widely used acidic ultra-zoom gels. We further demonstrated the usefulness of these modifications up to pH 9.5, although further improvements are still needed in that range. Thus, by extending the range covered by conventional ultra-zoom gels, the depth of analysis of two-dimensional gel electrophoresis can be significantly increased, underlining the importance of this method in differential proteomics.

2-Propanol↗
PubMed2001

Immunobiology of dendritic cells in the rat.

Dendritic cells (DC) are crucial orchestrators of the adaptive immune response. They are highly effective antigen samplers and have a unique ability amongst antigen presenting cells to activate naïve T lymphocytes and subsequently direct the quality of the immune response. Understanding how DC initiate and regulate immune responses requires in-depth knowledge of DC function at cellular and molecular levels. Research on the biology of DC has predominantly used in vitro-generated and ex vivo-isolated DC from mice and humans. It is, however, often difficult to relate such DC to those that actually exist in vivo. The model we have developed in the rat permits analysis of DC in a near-physiological setting, and provides a description of DC biology that other systems must take into account. In this review we focus on our own research on DC in the gastro-intestinal tract, covering a variety of concepts in DC biology, and relate our findings to the work of others, to provide an overall picture of what is known regarding the nature of this complex cell type in the rat.

Animals↗
PubMed2004

Dislocation creep in MgSiO3 perovskite at conditions of the Earth's uppermost lower mantle.

Seismic anisotropy provides an important observational constraint on flow in the Earth's deep interior. The quantitative interpretation of anisotropy, however, requires knowledge of the slip geometry of the constitutive minerals that are responsible for producing rock fabrics. The Earth's lower mantle is mostly composed of (Mg, Fe)SiO3 perovskite, but as MgSiO3 perovskite is not stable at high temperature under ambient pressure, it has not been possible to investigate its mechanical behaviour with conventional laboratory deformation experiments. To overcome this limitation, several attempts were made to infer the mechanical properties of MgSiO3 perovskite on the basis of analogue materials. But perovskites do not constitute an analogue series for plastic deformation, and therefore the direct investigation of MgSiO3 perovskite is necessary. Here we have taken advantage of recent advances in experimental high-pressure rheology to perform deformation experiments on coarse-grained MgSiO3 polycrystals under pressure and temperature conditions of the uppermost lower mantle. We show that X-ray peak broadening measurements developed in metallurgy can be adapted to low-symmetry minerals to identify the elementary deformation mechanisms activated under these conditions. We conclude that, under uppermost lower-mantle conditions, MgSiO3 perovskite deforms by dislocation creep and may therefore contribute to producing seismic anisotropy in rocks at such depths.

Journal Article↗
PubMed2006

An ab initio investigation of the O(3P)-H2(1sigma(g)+) van der Waals well.

We report an ab initio study of the van der Waals region of the O(3P)-H2 potential energy surface based on RCCSD(T) calculations with an aug-cc-pVQZ basis supplemented by bond functions. In addition, an open-shell implementation of symmetry-adapted perturbation theory (SAPT) is used to corroborate the RCCSD(T) calculations and to investigate the relative magnitudes of the various contributions to the van der Waals interaction. We also investigate the effect of the spin-orbit coupling on the position and depth of the van der Waals well. We predict the van der Waals minimum to occur in perpendicular geometry, and located at a closer distance than a secondary well in colinear geometry. The potentials obtained in the present study confirm the previous calculations of Alexander [M. H. Alexander, J. Chem. Phys., 1998, 108, 4467], but disagree with the earlier work of Harding and co-workers [Z. Li, V. A. Apkarian and L. B. Harding, J. Chem. Phys., 1997, 106, 942] as well as with recently refitted surfaces of Brandão and coworkers [J. Brandão, C. Mogo and B. C. Silva, J. Chem. Phys., 2004, 121, 8861]. Inclusion of spin-orbit coupling reduces the depth of the van der Waals minimum without causing a change in its position.

Energy Transfer↗
PubMed2005

An application of nanoindentation technique to measure bone tissue Lamellae properties.

Measuring the microscopic mechanical properties of bone tissue is important in support of understanding the etiology and pathogenesis of many bone diseases. Knowledge about these properties provides a context for estimating the local mechanical environment of bone related cells thait coordinate the adaptation to loads experienced at the whole organ level. The objective of this study was to determine the effects of experimental testing parameters on nanoindentation measures of lamellar-level bone mechanical properties. Specifically, we examined the effect of specimen preparation condition, indentation depth, repetitive loading, time delay, and displacement rate. The nanoindentation experiments produced measures of lamellar elastic moduli for human cortical bone (average value of 17.7 +/- 4.0 GPa for osteons and 19.3 +/- 4.7 GPa for interstitial bone tissue). In addition, the hardness measurements produced results consistent with data in the literature (average 0.52 +/- 0.15 GPa for osteons and 0.59 +/- 0.20 GPa for interstitial bone tissue). Consistent modulus values can be obtained from a 500-nm-deep indent. The results also indicated that the moduli and hardnesses of the dry specimens are significantly greater (22.6% and 56.9%, respectively) than those of the wet and wet and embedded specimens. The latter two groups were not different. The moduli obtained at a 5-nm/s loading rate were significantly lower than the values at the 10- and 20-nm/s loading rates while the 10- and 20-nm/s rates were not significantly different. The hardness measurements showed similar rate-dependent results. The preliminary results indicated that interstitial bone tissue has significantly higher modulus and hardness than osteonal bone tissue. In addition, a significant correlation between hardness and elastic modulus was observed.

Aged↗
PubMed1985

[Use of galascorbin as a fixative of histological material for light and electron microscopy].

A complex of sodium salts of gallic and ascorbic acids (galascorbin) is recommended as an additive to the fixative for improving the quality of histological material fixation. Its main advantage as compared to natural tannids is an easiness of penetration into the depth of tissues and, in comparison to other fixatives (aldehydes, alcohol), a more efficient fixation and retention of intra- and extracellular substances in tissues. Prescriptions of the galascorbic fixatives for light and electron microscopy are given. A method of staining of preparations specifically adapted for galascorbic fixation is suggested for light microscopy. Methods of both fixation and staining are intended for scientific purposes and for use by prosectors.

Acetates↗
PubMed1994

[In vivo fluorescence spectroscopy of human skin: principles and application to penetration measurements].

The fluorescence properties of untreated human skin and the penetration of topically applied drugs were measured in vivo using a commercially available fluorescence spectrometer which was adapted to in vivo-measurements on skin by means of optical fibres and a remote viewing head. The intensity and characteristics of the intrinsic fluorescences of human skin and their dependences upon several parameters like pigmentation, water content of the skin or depth of the horny layer are shown. The principles of the penetration measurements based on the fluorescence of the skin or the fluorescence of the drug topically applied to the skin are described and measurements of the penetration of some drugs are reported.

Fiber Optic Technology↗