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At least 19 recordsLinked to original sources
PubMed1986

Percutaneous transplantation of pulverized bone in rabbits.

The effects of percutaneous injection of the pulverized bone on osteogenesis at the site of bone defect were investigated in rabbits. Although the ceramic bone mixed with blood coagula showed the osteogenic capacity in fresh bone defects, it did not show this capacity in old bone defect. Injection of pulverized bone mixed with blood coagula resulted in greater bone formation than did pulverized bone mixed with saline. Three types of pulverized bone were used: ceramic bone, Kiel bone and autologous corticocancellous bone. Ceramic bone showed the greatest capacity in osteogenesis. These results suggest that the percutaneous injection of pulverized ceramic bone is effective in the treatment of fresh bone defects.

Animals↗
PubMed1972

Chromosome pulverization in micronuclei induced by tritiated thymidine.

Cultures of a pseudodiploid cell line (Don) of Chinese hamster origin were exposed to varying doses of tritiated thymidine (TdR-(3)H) for relatively long periods of time. In addition to previously observed chromosomal aberrations) such as breaks and reunions, a substantial number of interphasic cells with micronuclei and of metaphases associated with pulverized chromosomes was found; both phenomena were dependent on exposure time to and concentration of TdR-(3)H. The former phenomenon appeared to result from the effects of the beta-emissions originating in the TdR-(3)H. A possible interpretation for chromosome pulverization induction is presented, emphasizing the derivation of the pulverized material from micronuclei in a common cytoplasm with a metaphase nucleus. These observations further substantiate our previously advanced hypothesis regarding the essential role played by substances present in a mitotic cell in the induction of chromosome pulverization and nuclear membrane dissolution.

Animals↗
PubMed1986

Pulverized bone matrix as an injectable bone graft in rabbit radius defects.

A segment of the rabbit radius diaphysis was excised, demineralized, and pulverized. The demineralized matrix particles were mixed with autologous bone marrow from the femoral canal and injected into the defect from which it had been excised. On the contralateral side, the demineralized bone was reimplanted without pulverization, but with bone marrow. The bone yield was measured by radiographic planimetry and Tc99m MDP scintimetry. The forearms of the rabbits were sectioned into transverse segments, including the middle of the radius defect. The ash weights and the Ca45 content of these segments were measured. After two weeks, the ash weight was greater on the pulverized than on the unpulverized side; but by four weeks, measurements showed no difference. In general, the injectable bone matrix preparation did not interfere with bone repair. In comparing the Tc99m and Ca45 methods, the latter provided high-precision data with respect to the biologic variation.

Animals↗
PubMed1978

Some comments regarding chromosome pulverization (premature chromosome condensation or PCC, prophasing).

Premature chromosome pulverization (PCC) or prophasing is a much misunderstood cytological entity. It must be separated from chromosome damage caused by a number of chemical, physical and biological agents. Prophasing is observed in fused cells in which one of the constituent cells must be in metaphase and another in interphase. The morphology of the "pulverized" interphase nucleus will depend on the phase of the cell cycle in which the interphase cell was in when exposed to a substance present in the cytoplasm of the metaphase cell leading to "prophasing". Prophasing is a normal cellular phenomenon occurring prematurely or under abnormal conditions (fusion of cells) and its demonstration in human cells or tumors may be indicative of the presence of a virus (or its products) which leads to cell fusion, but does not play a role in prophasing.

Animals↗
PubMed1972

Laboratory mill for pulverizing and homogenizing nail specimens as an aid to microscopy and culture confirmation of onychomycosis.

A small mill has been developed for reducing nail clippings to a convenient size for microscopy and inoculation onto isolation media. The milling process acts to pulverize and homogenize the specimen. The use of a homogeneous sample in microscopy increases the opportunity for the discovery of fungal hyphae in a specimen. The use of a pulverized specimen increases the possibility of culture isolation by permitting greater numbers of potentially viable fungal cells to come into direct contact with the isolation medium.

Candida albicans↗
PubMed1976

Effect of pulverized implantation materials (plastic and glass ceramic) on growth and metabolism of mammalian cell cultures.

The effect of pulverized plastic and glass-ceramic materials (methylmetacrylate, MNA), which are used as implantation materials in surgical medicine, on cell growth, DNA synthesis rate (adjudged by incorporation of 3H-thymidine into DNA), glucose consumption and lactate production (glycolytic rate) was studied in asynchronous monolayer cultures of rather fast proliferating Ehrlich ascites tumor cells and rather slowly proliferating diploid human fibroblasts. Exposure of Ehrlich ascites cells to high concentrations (2 mg/ml; 10 ml medium per culture) of ceramic or plastic material resulted in a gradual inhibition of cell growth and DNA synthesis rate. Protein synthesis, as measured by the incorporation of 3H-leucine, was somewhat less affected than DNA synthesis. Also, the glycolytic rate of Ehrlich ascites cells was slightly but significantly decreased in the presence of 2 mg/ml ceramics or MMA. Exposure of Ehrlich ascites cells to 0.2 or 0.02 mg/ml over a period of 46 h revealed none or only slight inhibitory effects on growth, DNA synthesis or glycolytic rate. On the other side, growth, DNA synthesis and glycolytic rates of human fibroblasts were nearly not affected by the presence of the same concentrations (up to 2 mg/ml, incubation period: 92 h) of pulverized ceramic or plastic material (MMA). It is suggested that this differential cellular sensitivity might be related to differences in the binding (to the cell surface) or uptake of these substances and possibly to differential intracellular lysosomal activation.

Animals↗
PubMed1979

Degradation of bone matrix morphogenetic activity by pulverization.

The yield of new bone from implants of pulverized demineralized whole matrix and bone matrix gelatin declines as the particle size decreases in diameter below 125 microns. The corresponding increase in surface area and mechanically-induced free radicals is associated with an increase in solubility of bone matrix proteins. These changes in physiocochemical properties and the concomitant reduction in bone yield suggest that prolonged pulverization denatures a bone morphogenetic protein (BMP).

Animals↗
PubMed1978

Induction of pulmonary carcinoma in rats by chronic inhalation of dust from pulverized asbestos pipe covering.

Rats and hamsters were exposed to the dust of pulverized asbestos pipe covering at an average concentration of 85 mg/m(3) for 6 h/d, 5 d/wk, for 7 mo, followed by a lifetime observation period. In rats, the pulmonary responses were alveolar adenomatous proliferation, nonprogressive fibrosis, squamous metaplasia, and a substantial incidence of pulmonary carcinoma formation. A smaller group of hamsters exposed under these conditions experienced an earlier onset of mortality than control hamsters, which were not subjected to the exposure regimen. Although this prevented conclusive evaluation of the pulmonary response in this species, no pulmonary neoplasms were noted in the surviving hamsters.

Animals↗
PubMed1978

Preliminary results of phage typing of coagulase-negative staphylococci with the set of typing phages of Pulverer and co-workers.

120 strains of Staphylococcus epidermidis isolated from clinical material were typed with the set of 16 test phages described by Pulverer et al. (1975). 58 (48%) strains were typable with RTD and additionally 12 strains with 100 times RTD. The pattern Ph10/U14/U16 was observed most common (36 strains), followed by the pattern U14/U16 (11 strains). One strain showed lysis reactions with all typing phages. With 61 strains phage U14 gave a lysis whereas phage U20 reacted only with 4 strains. The S. epidermidis phages were not specific for this species, at least some of these showed lysis reactions with S. aureus strains. The lysis pattern most often observed was Ph10/U14/U16. There was no correlation between the patterns given by the S. aureus test phages and those by the S. epidermidis phages.

Bacteriophage Typing↗
PubMed1992

Electron spin resonance studies of dental composites: effects of irradiation time, decay over time, pulverization, and temperature variations.

Polymerization induced by UV-VIS light of composite dental materials produces a solid matrix within which terminal radicals of non-polymerized monomers remain trapped. Electron Spin Resonance (ESR) allowed three different types of radicals to be identified. The analysis of ten normally available commercial products gave information on: (1) the propagation of the conversion reaction as a result of exposure to light; (2) the time necessary for the decay of each type of radical; and (3) the variations with temperature and the effects of shattering on the materials under study. The presence of inorganic filling material slowed the process of polymerization, while it accelerated the decay of radicals. It was suggested that the nature of these processes depended on the composition of the base resin materials, whereas it did not depend on the sizes of the filler particles. Moreover, the complete propagation of the conversion reaction needed a period of light exposure greater than that currently suggested by the manufacturers. The structural stability and the resistance of the composites were confirmed by both the long period of decay and the high temperatures needed to overcome the potential barrier for starting the radical decay process. Finally, the composite shattering investigation indicated that particles removed by surface abrasion experience rapid radical decay, thus reducing the possibility of harmful effects on internal organs.

Composite Resins↗