Synchrotron ultraviolet microspectroscopy on rat cortical bone: involvement of tyrosine and tryptophan in the osteocyte and its environment

Alcohol induced osteoporosis is characterized by a bone mass decrease and microarchitecture alterations. Having observed an excess in osteocyte apoptosis, we aimed to assess the bone tissue biochemistry, particularly in the osteocyte and its environment. For this purpose, we used a model of alcohol induced osteoporosis in rats. Bone sections of cortical bone were investigated using synchrotron UV-microspectrofluorescence at subcellular resolution. We show that bone present three fluorescence peaks at 305, 333 and 385 nm, respectively corresponding to tyrosine, tryptophan and collagen. We have determined that tyrosine/collagen and tryptophan/collagen ratios were higher in the strong alcohol consumption group. Tryptophan is related to the serotonin metabolism involved in bone formation, while tyrosine is involved in the activity of tyrosine kinases and phosphatases in osteocytes. Our experiment represents the first combined synchrotron UV microspectroscopy analysis of bone tissue with a quantitative biochemical characterization in the osteocyte and surrounding matrix performed separately.     

Home Non-Invasive Ventilation Fails to Improve Quality of Life in the Elderly: Results from a Multicenter Cohort Study

BackgroundHome non-invasive ventilation (NIV) is a widely used treatment for chronic hypoventilation but little is known on its impact in the elderly. In a multicenter prospective cohort study, we studied tolerance and efficacy of domiciliary NIV in patients aged 75 or more compared to younger ones.ConclusionNIV was efficient in the elderly while evaluation at 6 months showed a good adherence but failed to improve HRQL.     

Aerial flow of barley yellow dwarf viruses and of their vectors in western France

During the years 1989–1992 cereal aphids were caught alive in a low level (1.5 m high) suction trap operated in Le Rheu (Brittany, France) and tested for BYDV transmission. In most cases comparisons with data collected simultaneously by a 12.2 m suction trap operating in the same site resulted in good relationships between weekly catches at both heights. Results from transmission tests showed that: (i) the two main BYDV vectors were Rhopalosiphum padi and Metopolophium dirhodum during the years of experiment; (ii) PAV and MAV were the commonest viruses and RPV was relatively scarce; (iii) during spring M. dirhodum appeared to be the most important MAV vector and nearly as good a PAV vector as R. padi; (iv) during autumn R. padi was the only vector of the three viruses with mixed transmission allowing it to transmit also MAV probably by heteroencapsidation. To give an indication of the risk of infection, infectivity indices were calculated by multiplying the numbers of aphids caught by the 12.2 m suction trap by the proportion that were infective. These infectivity indices agreed with field records of primary infections.     

Elemental levels and relationships in the Flacourtiaceae of New Caledonia and their significance for the evaluation of the ‘serpentine problem’

Summary Sixteen elements were determined in 156 specimens of 47 species of New Caledonian Flacourtiaceae including the genera Casearia, Homalium, Lasiochlamys and Xylosma. The data were used to study inter-elemental relationships, particularly those involving nutrient elements, magnesium and phytotoxic elements such as chromium, cobalt and nickel. Phytotoxic chromium was not accumulated to any marked degree by any taxon. Cobalt was inversely correlated with boron and sodium, and nickel with both nutrients as well as manganese. The data seemed to indicate the overriding controlling factor of reduced nutrient uptake caused by elements present in high concentrations in serpentinic substrates. It would seem that this reduced uptake is a major factor in the serpentine problem, at least as far as the Flacourtiaceae and the New Caledonian environment is concerned. By contrast, the toxic effects of elements such as nickel, cobalt and chromium seems less important.     

Plant extinction in New Caledonia: protection of sclerophyll forests urgently needed

The sclerophyll forests which once extended over the lowlands of the west coast of New Caledonia are now reduced to small fragments representing about 2% (10 000 ha) of their original area. Much of the remaining forests are degraded. Threats to sclerophyll forests come from land clearance, grazing by cattle or deer, and fire. In sclerophyll forests, 223 endemic phanerogam species occur and 59 of these are specific to this forest type. Several of the 59 specific species are known only from a few plants at a single locality and are critically endangered. Pittosporum tanianum sp. nov. became extinct shortly after its discovery in 1988, and becomes the first documented plant extinction in New Caledonia. A further 15 species of New Caledonian plants, not recorded for several decades, are discussed, and it is concluded that between 4 and 9 of them may be extinct. The existing reserves containing sclerophyll forests are inadequate to protect the remaining biodiversity of the forests. Four immediate steps needed to protect sclerophyll forests are (i) restoration of Leprédour Island; (ii) purchase and restoration of selected privately owned forests; (iii) management of publicly owned forest near Népoui; and (iv) ex situ conservation of certain species.