Showing papers by "University of Texas Health Science Center at Houston published in 1969"
TL;DR: The idea that chromosome damage may not be the major cause of cell killing is suggested by the observations that frequency of first division lethal sectoring showed no age dependence and multipolar mitosis appeared to account for a significant proportion of non-surviving clones at low doses.
Abstract: SummaryProliferation kinetics of x-irradiated mouse L-P59 fibroblasts were studied by constructing cell pedigrees from photographic records. Parameters of proliferation showed marked age dependence; early G1 cells were most resistant and late S-G2 cells were most sensitive in terms of reduction in probability of division, increase in generation time, and induction of abnormal mitotic figures (multipolar and incomplete mitoses). Division probabilities were higher at first division than at subsequent divisions, and cell death in some pedigrees was absent until the fourth generation or later. Prolongation in generation time occurred during several post-irradiation divisions, most noticeably in abortive clones. The idea that chromosome damage may not be the major cause of cell killing is suggested by the observations that (1) frequency of first division lethal sectoring showed no age dependence; (2) multipolar mitosis appeared to account for a significant proportion of non-surviving clones at low doses.
189 citations
TL;DR: The phenomenon of leukopedesis in gingival and periodontal tissues was measured by counting the number of orogranulocytes migrating into the mouth during repeated intervals of 30 seconds and classified as a non-subjective laboratory routine for indexing oral inflammation.
Abstract: The phenomenon of leukopedesis in gingival and periodontal tissues was measured by counting the number of orogranulocytes migrating into the mouth during repeated intervals of 30 seconds. Measurements were carried out with a computerized electronic cell grading system and classified as a non-subjective laboratory routine for indexing oral inflammation. For orogranulocytic migratory rate (OMR) readings above 1.2 X 106/30 sec, a minimum of three determinations is required for reliability. Single readings suffice for OMR's below 0.5 X 106/30 sec, which indicates that the system is suitable for mass screening purposes.
47 citations
TL;DR: Three dentists independently diagnosed subjects as bruxist or nonbruxist and intense masseter electromyographic activity was found to be associated with diagnosis of severe bruxism.
Abstract: Three dentists independently diagnosed subjects as bruxist or nonbruxist. Ratings were compared with polygraph recordings made in the sleep laboratory. Intense masseter electromyographic activity was found to be associated with diagnosis of severe bruxism.
28 citations
15 citations
TL;DR: Radioisotopes of riboflavin, biotin, and folic acid were parenterally administered to marmosets to determine whether the salivary glands contribute to the vitamin content of saliva.
Abstract: Radioisotopes of riboflavin, biotin, and folic acid were parenterally administered to marmosets to determine whether the salivary glands contribute to the vitamin content of saliva. Examination after injection showed that there were measurable amounts of each test vitamin in all samples of pilocarpine-stimulated saliva obtained from the test animals.
6 citations
TL;DR: It can be concluded on the basis of the data presented that the functional integrity of the mouse embryo cell genome is required for the replication of polyoma virus, but not for EMC virus.
Abstract: Ultraviolet irradiation and actinomycin D impair the capacity of mouse embryo (ME) cells to support the replication of polyoma virus, but not of encephalomyocarditis (EMC) virus. The loss in capacity for polyoma virus synthesis was an "all-or-none" effect and followed closely upon the loss in cellular capacity for clone formation. Cells treated with either agent produced polyoma "T" antigen, but did not synthesize polyoma structural protein. Infection of untreated ME cells with polyoma virus produced marked stimulation of both deoxyribonucleic acid (DNA) synthesis and ribonucleic acid (RNA) synthesis. ME cell cultures irradiated with ultraviolet for 30 sec at 60 muw/cm(2) or treated with actinomycin D at 0.1 mug/ml for 6 hr prior to infection were incapable of synthesizing DNA or RNA, even after infection with polyoma virus. Irradiation of cells during infection produced cessation of synthesis of both RNA and DNA. Addition of actinomycin D during infection did not inhibit DNA synthesis but abolished RNA synthesis and reduced the yield of polyoma virus to 10% of that in untreated infected cultures. Both agents lost the ability to prevent replication of a full yield of polyoma virus when administered 30 hr after infection or later. The period after which neither agent inhibited polyoma replication corresponded with the period at which maximal RNA synthesis in untreated infected cultures had subsided. It can be concluded on the basis of the data presented that the functional integrity of the mouse embryo cell genome is required for the replication of polyoma virus, but not for EMC virus. Whereas the requirement for cellular DNA-dependent RNA synthesis for polyoma virus replication has been demonstrated, the exact nature of the host-cell function remains to be elucidated.
1 citations