Keys to success in lingual therapy. Part 1.
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Dental Bonding↗
Biomedical subjects
J R Smith
Publications and source records attributed to J R Smith.
Glucocorticoid receptors in human leukemias and related diseases.
The evidence to date is compelling that steroid initiated cell lysis involves participation of the glucocorticoid receptor. Not only do the concentrations and specificity of hormones for cell lysis and receptor occupancy correspond, but also steroid resistant cells selected with or without prior mutagenesis often have altered receptors. The glucocorticoid receptor protein from humans and other species is a approximately 95,000 d, thiol group-containing monomer, prone to aggregation when "unactivated." After having bound steroid and been "activated," the monomeric steroid-receptor complex is altered in charge and shape so that its binding to chromatin and DNA is greatly enhanced. Simple measurement of numbers of receptor sites in cells from patients with various blood dyscrasias has given, in some disease, good correlations between high numbers of receptor sites and good therapeutic response. These correlations are strongest for childhood acute lymphoblastic leukemia (ALL) and for non Hodgkins' lymphoma. In other diseases, notably acute myelogenous leukemia, such correlations have not been found. The CEM human ALL line has been used in vitro to study mechanisms of glucocorticoid action and resistance. The requirement for "activated" steroid-receptor complex for cell lysis is shown in these cells by the spontaneous occurrence of steroid resistant, activation-labile receptor mutants. A second category of resistant cells with normal receptors has been defined. Treatment of these "lysis defective" resistant cells with compounds which result in DNA demethylation can render them steroid sensitive. Since DNA demethylation can allow formerly silent genes to become transcribed, it is possible that one or more genes specific for lysis has been "opened" in such cells. Alternatively, DNA demethylation may produce a general biochemical effect on the cell which renders it susceptible to lysis. Mutagenized CEM cells selected for steroid resistance give rise to a third class of mutants, which are deficient in receptor quantity. Each of these classes of steroid resistant cells contains information pertinent to understanding the use of glucocorticoids and the role of glucocorticoid receptors in human leukopathic disease.
Animals↗
Obstructive jaundice from hepatic amyloidosis in a patient with multiple myeloma.
A patient with multiple myeloma is described who developed severe intrahepatic cholestasis secondary to hepatic deposition of amyloid. This is the first reported case of this complication's developing in a patient with multiple myeloma.
Amyloidosis↗
Copper exposure and ciliary function in gill tissue of Mytilus californianus.
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Animals↗
Senescent and quiescent cell inhibitors of DNA synthesis. Membrane-associated proteins.
Cytoplasts derived from senescent and quiescent human diploid cells inhibit DNA synthesis initiation when fused with cells capable of proliferation. When the cytoplasts were subjected to a variety of conditions (trypsin and cycloheximide treatment and growth on fibronectin), this inhibitory activity was lost, suggesting that the inhibitors involved were proteins associated with the surface membranes of the cells. We have studied the quiescent cell inhibitor in greater detail and determined that surface membrane-enriched preparations isolated from quiescent cells and proteins extracted from these membrane preparations have DNA synthesis-inhibitory activity.
Cell Division↗
Entry into S phase is inhibited in human fibroblasts by rat liver poly(A)+RNA.
Initiation of DNA synthesis was inhibited in human fibroblasts following microinjection with poly(A)+RNA derived from normal rat liver. After sucrose gradient sedimentation of the RNA, the inhibitory activity was found to be limited to two adjacent fractions. Dilution experiments suggest a minimum abundance level of 0.015% for this mRNA(s). Studies on the kinetics of this inhibition indicate a reversible inhibition with a duration of approx. 10 h.
Animals↗
Intramitotic variation in proliferative potential: stochastic events in cellular aging.
A series of mitotic pairs of cells were isolated and the proliferative potential of each cell determined. Although the proliferative potentials of the two cells of a single pair were similar for most pairs examined, in a significant proportion large differences were observed. These results suggest a strong stochastic component in the somatic inheritance of proliferative potential. This observation provides the basis for refinement of a mathematical model for in vitro cellular aging.
Cell Division↗
CGS 12970: a novel, long acting thromboxane synthetase inhibitor.
CGS 12970 is a potent selective inhibitor of human platelet thromboxane synthetase in vitro (IC50 = 12 nM). It is four orders of magnitude less potent as an inhibitor of sheep seminal vesicle cyclooxygenase, bovine aorta prostacyclin synthetase and human leucocyte 15-lipoxygenase. The compound inhibited collagen-induced thromboxane B2 production by human platelets in vitro without an effect on the accompanying platelet aggregation induced by collagen, ADP, platelet activating factor, thrombin, arachidonic acid or the prostaglandin mimetic, U 46619. Administration of CGS 12970 to rats inhibited collagen-induced thromboxane B2 production but had no effect on platelet aggregation ex vivo. It also had no effect on platelet aggregation induced by thrombin or on plasma clotting times. A single oral dose of 1 or 3 mg kg-1 to rabbits inhibited thromboxane B2 production in clotting blood ex vivo for 12 or 24 h respectively. CGS 12970 inhibited thromboxane B2 production in vivo induced by intravenous administration of collagen to rats or calcium ionophore to guinea-pigs. In both cases there was a concomitant elevation of immunoreactive 6-keto-prostaglandin F1 alpha but no effect on the induced thrombocytopenia. As with other thromboxane synthetase inhibitors, CGS 12970 prolonged tail bleeding time in the rat. However, CGS 12970 was not as potent as other thromboxane synthetase inhibitors in this test. In addition to these usual effects of thromboxane synthetase inhibitors, CGS 12970 inhibited the thrombocytopenia induced by the Forssman reaction or ADP administration. In these tests the effect of the compound was of short duration. 8 CGS 12970 had no effect on the thrombocytopenia associated with the Arthus reaction which distinguishes it from cyclo-oxygenase inhibitors. It also had no effect on thrombus formation on a cotton thread in an arteriovenous shunt in the rat.
Animals↗
Genetic amniocentesis: significance of intraamniotic bleeding and placental location.
Simultaneous ultrasound was used to determine if there was a correlation between visualized intraamniotic bleeding, placental location, and fetal-maternal hemorrhage. It was hoped to then determine which Rh-negative patients should receive Rh immunoglobulin. Visualized intraamniotic bleeding showed no correlation to fetal-maternal hemorrhage. Intraamniotic bleeding was commonly associated with needle insertion through an anterior placenta, but also occurred regardless of placental location and in the absence of placental needle traversal. No correlation was found between placental location and fetal-maternal hemorrhage as evidenced by evaluation of maternal serum alpha-fetoprotein. The Kleihauer test was not as sensitive as alpha-fetoprotein.
Amniocentesis↗
Automatic recognition of spike and wave bursts.
This paper reviews previous methods and describes a new method for the detection of spike and wave bursts in a single EEG channel. The complete detector is readily implemented in a 16-bit microprocessor. The burst detection relies on the detection of both spikes and waves and also imposes a requirement on the repetition rate of the slow waves. The system agreement with electroencephalographers was over 90% for spike and wave bursts longer than 3 sec in duration, with a false detection rate of one error in 5.8 h for bursts of the same length. The system also computes the mean value and variance of the amplitude and duration of the spikes and slow waves as well as the period of the spike and wave complexes. The EEGs of 6 patients suffering from petit mal epilepsy were analyzed. The variance of the amplitude measures was found to be much greater than that of the period measurements. For all patients the repetition period of the waves decreased for longer bursts, as did the variability of the repetition period. The difficult problem of false detections due to artifacts is discussed in detail.
Action Potentials↗
Expression of the platelet procoagulant activity in vivo in thrombus formation in an extracorporeal shunt in the rat.
The interaction of platelets and the coagulation system has been investigated in vivo on a cotton thread implanted in an arteriovenous shunt in the rat. Depletion of the circulating platelet count with anti-platelet antibody reduces both thrombus deposition and 125I-labelled fibrinogen incorporation demonstrating the platelet behaviour with either anagrelide or prostacyclin decreases thrombus deposition by a greater extent than that expected from the platelet content of the thrombus. Treatment with warfarin also dramatically decreases both formation and 51Cr-labelled platelet deposition demonstrating the important role of the coagulation system in platelet aggregation in this model. Treatment with Arvin or with heparin also reduced the thrombus weight. It is concluded that this is a model of bidirectional platelet interaction with the coagulation system and may have similarities with thrombosis which occurs in extracorporeal shunts in man.
Animals↗
Digital subtraction angiography in head and neck radiology.
Intravenous digital subtraction angiography (IVDSA) was used to evaluate 44 patients with suspected otolaryngologic abnormalities. Sixteen had IVDSA for pulsatile tinnitus or suspected glomus tumor of the petrous bone. Nine patients were evaluated because of pulsatile neck masses, and 12 others had suspected tumors of the neck, face, and paranasal sinuses. Seven had IVDSA following head and neck trauma. The technique of examination is described. The current indications of IVDSA in head and neck radiology are discussed. It is concluded that IVDSA is a suitable substitute for conventional angiography for many otolaryngologic conditions and, because of its safety, can be used more liberally.
Adult↗
Inhibition of DNA synthesis in senescent-proliferating human cybrids is mediated by endogenous proteins.
Cytoplasts were prepared from senescent human diploid fibroblasts. Brief treatments of the senescent cells with cycloheximide or puromycin prior to or after enucleation eliminated the ability of senescent cytoplasts to block initiation of DNA synthesis in senescent-young cybrids. Senescent cells treated with cycloheximide, enucleated and allowed to recover in complete medium without cycloheximide, regained the ability to block initiation of DNA synthesis in senescent-young cybrids. These results support the hypothesis that senescent cells synthesize an inhibitor of DNA synthesis which is either a protein(s) or its activity is mediated by a protein(s) found in the cytoplasm of the senescent cell.
Cell Division↗
The two-dimensional polypeptide profile of terminally non-dividing human diploid cells.
We have used high resolution two-dimensional polyacrylamide gel electrophoresis (PAGE) to compare the polypeptides synthesized by normal human diploid fibroblasts cells which have significant proliferative capacity with those of cells which are terminally non-dividing. Normal cells that are terminally non-dividing (i.e., have no remaining proliferative potential) synthesize two polypeptides that are not detected in young cells which are either actively proliferating or growth arrested by incubation in medium containing a low concentration of serum (0.3%) for 72 h. Continued maintenance of young cells in the growth-arrested state ultimately leads to the detectable synthesis of one of the polypeptides synthesized by terminally non-dividing cells. Some preliminary biochemical properties of these two polypeptides are examined.
Cell Cycle↗
Prostaglandin endoperoxides and thromboxane A2 in thrombus formation in the hamster cheek pouch in vivo.
Electrical stimulation in the presence of ADP of arterioles of the hamster cheek pouch caused endothelial damage and white thrombus formation. The thrombus formation was inhibited by cyclo-oxygenase inhibitors aspirin and sulphinpyrazone and its thioether derivative G 25671. Thromboxane synthetase inhibitors N-(7-carboxyheptyl) imidazole and butylimidazole failed to inhibit thrombus formation, although in the same doses both compounds inhibited serum levels of thromboxane. These results indicate that thromboxane is not important in thrombus formation in the hamster, but that prostaglandin endoperoxides are more significant. However, it is possible that the inhibition of white thrombus formation by aspirin, sulphinpyrazone and G 25671 may be mediated by a different mechanism altogether.
Animals↗
Aging of cells in culture.
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Cell Differentiation↗
Experimentally induced severe canine parvoviral enteritis.
Severe enteritis was produced in recently weaned, 8-week old pups 3 to 9 days after being given parvovirus by mouth. The most severe manifestations of disease were observed 7 days after infection, when one pup died. Viraemia was detected on days 4 and 5 and a severe leucopenia was present 6 to 8 days after infection. Antibody was demonstrated in serum 4 days after infection, high titres being present 3 days later. Sequential pathological studies revealed necrosis of Peyer's patches on day 3. Between days 5 and 7 typical lesions of the disease became widespread with necrosis of tonsil and thymus being prominent. By the fifth day after infection viral inclusion bodies were numerous. Virus isolation from tissues was greatest at this stage and had diminished by the seventh day. Although tissue repair was well advanced by the tenth day thymic necrosis remained prominent and villous atrophy was still present on day 13. Based on these findings a possible pathogenesis is discussed.
Acute Disease↗