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Biomedical subjects

S Palle

Publications and source records attributed to S Palle.

26 records · Page 2Linked to original sources
PubMed1987

Bone embedding in pure methyl methacrylate at low temperature preserves enzyme activities.

Pure Methyl Methacrylate (MMA), a widely used embedding medium for undecalcified bone studies, was polymerized at low temperature (4 degrees C). MMA was prepared by a new purification procedure yielding a absolutely anhydrous and catalysed resin. The redox system benzoyle peroxide/NN-Dimethylanilin was used as the catalyzer-initiator system providing free radicals for the MMA chemical polymerization. Since the reaction is inhibited at -20 degrees C, complete infiltration of blocks is achieved within 3 d. Polymerization took place at +4 degrees C. The method provides undecalcified bone sections suitable for histomorphometric analysis of osteoid tissue, tetracycline bone labeling and Tartrate Resistant Acid Phosphatase. Enzyme histochemistry was shown to be possible in pure MMA embedded bones, when this low temperature embedding was used.

Alkaline Phosphatase↗
PubMed1987

Effects of a 120 day period of bed-rest on bone mass and bone cell activities in man: attempts at countermeasure.

The effects of immobilization on bone mass and bone remodeling in patients with spinal cord injuries are known to simulate weightlessness-induced bone changes in astronauts. Nevertheless, immobilization has never been investigated using histomorphometric studies in healthy volunteers. Twenty healthy male volunteers participated in a '120 day bed-rest' experiment in the USSR. Bone biopsy cores of iliac crest were taken before and at the end of the period of bed-rest. The subjects were divided into five groups. Five subjects underwent a normal ambulatory life (control subjects); three subjects were placed on continuous bed-rest for 120 days (complete immobilization); four subjects were immobilized and underwent a controlled training program; four subjects were immobilized and received treatment with potassium diphosphonate (ethane-1,hydroxy-1,diphosphonate 900 mg/day, per os); and four subjects were immobilized and received diphosphonate plus physical exercise. Parameters of bone mass and bone cellular activities (osteoblastic formation and osteoclastic resorption) were measured using automatic and semi-automatic image analysis systems. Bone mass remained constant in each group. Cellular activity measurements showed that in completely immobilized men, the mineralization rate was lower than in controls without change in osteoid parameters; in contrast, osteoclastic parameters were increased. In immobilized men given the training program, bone formation was normal and bone resorption was increased. In immobilized men treated with diphosphonate, osteoid parameters and resorption activity were decreased. In immobilized men with diphosphonate plus training, the osteoid parameters and the resorption activity were reduced but to a lesser degree than in immobilized men with diphosphonate alone. Failure of bone loss in normal immobilized subjects differed from results found in paraplegic patients. However, a decrease in mineralization rate and an increase in bone resorption activity were found in both studies. Exercise stimulated bone resorption and diphosphonate inhibited the osteoclastic activity. These data emphasize the difficulties in finding good models to stimulate spaceflight conditions on earth. Comparative studies must be done using bone biopsies to determine more precisely the effects of weightlessness on the human skeleton.

Adult↗
PubMed1987

[Effects of weightlessness on osseous tissue of the rat after a space flight of 5 days (Cosmos 1514)].

Five pregnant female growing rats have been orbited for five days aboard the Cosmos 1514 soviet biological satellite. They were compared to five female rats kept in vivarium and five female conditioned rats in synchronised way. Histomorphometric studies were performed in order to investigate: 1. The early effects of weightlessness on the bone mass in loading (tibiae and femur) and unloading bones (thoracic and lumbar vertebrae). 2. The changes of osteoblastic and osteoclastic activities. A short exposure does not induce changes in the bone mass and the inner structure of loading and unloading bones. These results fit in well with human data available in the literature: they show that weightlessness doesn't change bone mass in the early phase of a spaceflight. However extrapolation of animal results to men is discussed. In unloading bones (vertebrae) osteoblastic activity was not measurable. Osteoclasts detected by histoenzymologic method don't change as far as their number per mm3 of trabecular bone is concerned. However the number per mm2 of trabecular area increases. It seems likely that an increase of the osteoclastic population occurs in trabecular bone. In loading bones, formation activity (appreciated by the measurement of osteoid seam thickness) and total osteoclastic resorption surfaces were not modified. These results are different from those of longer flights.

Animals↗
PubMed1987

[Quantitative histological study of the bone mass and cellular activity after 120-days decubitus. Trial of preventive protocols].

Bone biopsies of iliac crests, performed at the beginning and the end of a decubitus period of 120 days, were studied in 20 healthy volunteers men. The purpose of this experiment is to simulate the bony alterations of astronauts. The bony mass of all bed-ridden patients remained constant. In strictly immobilized patients, the rate of bony mineralization is decreased and the osteoclastic resorption activity is stimulated. In bed-ridden patients subjected to preventive physical exercises, the bony formation and resorption are increased. When prevention is administered with the use of a diphosphonate, the osteoid and osteoclastic parameters are decreased. When both types of prevention are administered, the osteoid parameters and the resorption activity are decreased but less markedly than in patients treated with diphosphonate alone.

Adult↗
PubMed1986

Permanent preservation of whole alizarin red S skeletons by clearing and embedding in polyester resins.

A one-step clearing and embedding procedure for alizarin red S stained skeletons is described. Embryos are fixed in formalin, skinned and eviscerated. After staining in a 10 mg/liter solution of alizarin red S in 5% aqueous KOH, specimens are dehydrated in a graded series of acetone-polyester monomer solutions. Finally, the specimens are embedded at room temperature in the polyester resin. A special reusable metallic mold is described for embedment of large fetuses. Specimens previously cleared in glycerol can be processed with this method.

Anthraquinones↗