Publications

Aluminum-related osteomalacia has been a topic of major interest for some time. Patients on dialysis who are affected exhibit reduced parathyroid function and osteomalacia associated with high levels of aluminum in the extracellular fluid and tissues. In bone, aluminum is found in the interface between mineralized and nonmineralized osteoid. In the present study we attempted treatment of the aluminum-related bone disease with DFO, a potent chelating agent. A thyroparathyroidectomized patient on hemodialysis with proven osteomalacia and aluminum deposits in bone received DFO 3 times/week for 1 year. Consequently, there was a marked improvement in his skeletal status, both clinically and histologically. This was associated with aluminum deposits within the mineralized component of bone as well as elevated parathyroid function measured in blood and bone. These findings suggest that calcification may occur despite the presence of aluminum in the mineralizing front. The main beneficial effect of DFO could be relief of the inhibitory action of aluminum on parathyroid cells and osteoblasts.

A review with 33 refs. discussing biomodels of photosynthesis (composites of artificial photosystems linked to biocatalysts) and artificial models of photosynthesis (artificially tailored systems that mimic natural photosynthesis). [on SciFinder(R)]

Two major immunocross-reactive polypeptides of the Drosophila nuclear envelope, distinguishable in interphase cells on the basis of one-dimensional SDS-PAGE mobility, have been localized to the nuclear lamina by immunoelectron microscopy. These have been designated lamins Dm1 and Dm2. Both lamins are apparently derived posttranslationally from a single, primary translation product, lamin Dm0. A pathway has been established whereby lamin Dm0 is processed almost immediately upon synthesis in the cytoplasm to lamin Dm1. Processing occurs posttranslationally, is apparently proteolytic, and has been reconstituted from cell-free extracts in vitro. Processing in vitro is ATP dependent. Once assembled into the nuclear envelope, a portion of lamin Dm1 is converted into lamin Dm2 by differential phosphorylation. Throughout most stages of development and in Schneider 2 tissue culture cells, both lamin isoforms are present in approximately equal abundance. However, during heat shock, lamin Dm2 is converted nearly quantitatively into lamin Dm1. Implications for understanding the regulation of nuclear lamina plasticity through normal growth and in response to heat shock are discussed.

Mechanical load influences the remodelling of skeletal tissues. In the mandibular condyle, occlusal alterations and the consequent mechanical stimulus induce changes in chondrocytes and cartilage mineralization. In the present study we quantified in the mandibular condyle the effect of occlusal interference on remodelling of the subchondral bone. Computerized histomorphometry after 5-21-day exposure to the influence of a unilateral occlusal splint revealed an increased rate of trabecular remodelling, consisting of enhancement in osteoblast and osteoclast numbers and activities. The bone formation parameters reached their high values on Days 5 or 9 and remained stable thereafter. Bone resorption showed a gradual increase throughout the experimental period. These results further characterize the temporomandibular joint reaction to occlusal alterations. It is suggested that the present increase in bone turnover together with the known enhancement in chondrogenesis are part of a process of functional adaptation in response to mechanical stimulus.

The photoredn. of CO2/HCO3- in aq. soln. contg. deazariboflavin as photosensitizer, Me viologen as primary electron acceptor, and oxalate as electron donor is studied. Visible light was used to induce photoredn., and Pd colloid stabilized by β-cyclodextrin was used as redn. catalyst. Examn. of the mechanism of CO2/HCO3- photoredn. to formate indicates that Pd-β-cyclodextrin is extremely important as catalyst in the redn. and appears to activate bicarbonate toward the photoredn. process. [on SciFinder(R)]

A Portuguese translation appeared as 'Portugueses em Amesterdão 1600-1680' (1988).