Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A study was conducted to evaluate using SEM the earliest events of initial blood clot formation on periodontally diseased root surfaces given various treatments. Six teeth with periodontal disease were extracted from six different subjects and were studied in two individual groups. In the first group the root surfaces were divided into three individual treatment areas: (a) intact periodontal ligament, (b) planed, (c) planed and also treated with 1% citric acid. The root surfaces in the second group were likewise divided into three treatment areas: (a) intact periodontal ligament, (b) planed, (c) planed and topically conditioned with tetracycline HCl. All the roots were reinserted into the original extraction sites, and then removed at either "zero" (less than 5 s), one or 3 min and prepared for SEM evaluation. It was observed that organized clot formation occurred more rapidly in the treatment areas where both root planing and topical conditioning with tetracycline HCl had been done.
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PMID:Effects of various root surface treatments on initial clot formation: a scanning electron microscope study. 207 97

The adsorption of 2-hydroxyethyl methacrylate (HEMA) on bovine dentin from aqueous solution was examined to clarify the priming effects of HEMA on dentin bonding. HEMA adsorption was characterized by: (1) slow attainment of equilibrium at higher concentrations (after 72 h); (2) a linear isotherm with a maximum possible adsorption, where an abrupt horizontal plateau occurred; (3) the large adsorption of ca. 2.5% by weight at the plateau; and (4) a vertical initial slope of the isotherm. The morphological difference between dentin powder surfaces before and after adsorption could not be determined. After heating, however, dentin powder which adsorbed HEMA was more resistant to demineralization with 6N HCl than the powder which did not adsorb. SEM examinations demonstrated that there was a demineralization-resistant dentin layer in tooth which adsorbed HEMA. The results indicated that HEMA infiltrated into intertubular dentin during adsorption.
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PMID:Adsorption of 2-hydroxyethyl methacrylate on dentin from aqueous solution. 209 9

We tested the hypothesis that amino acids in a parenteral nutrition (PN) solution would result in the decreased metabolism of a model compound, lidocaine. One bolus infusion of lidocaine HCl (1 mg/kg) was administered to seven healthy subjects in association with each of three nutrient regimens: (a) a standard PN solution, (b) 10% dextrose water (D10W), and (c) a meal (control) containing similar fluid volume and caloric, protein, and sodium content as the PN solution. Intravenous nutrients were infused consecutively in a random order at 1 L/12 h. Intravenous and control studies were performed 28 days apart. There was no significant difference in the means (+/- SEM) of total body clearance [7.70 +/- 0.70 (PN) versus 6.78 +/- 0.79 (D10W) versus 7.86 +/- 0.93 (control) ml/min kg], half-life [74.0 +/- 12.2 (PN) versus 89.6 +/- 4.35 (D10W) versus 79.2 +/- 7.22 (control) min], volume of distribution [0.82 +/- 0.15 (PN) versus 0.88 +/- 0.13 (D10W) versus 0.78 +/- 0.13 (control) L/kg], and the fraction of unbound lidocaine in the serum [0.34 +/- 0.025 (PN) versus 0.36 +/- 0.019 (D10W) versus 0.33 +/- 0.020 (control)] among the three nutrient regimens. The concentration-time course of the active metabolite, N-ethylglycyl-2,6-xylidide, did not differ significantly regardless of the nutritional regimen used. Our study indicates that amino acids used for PN do not have any acute effect on lidocaine pharmacokinetics in healthy subjects.
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PMID:Lack of acute effect on lidocaine pharmacokinetics from parenteral nutrition. 210 8

The bioavailability and pharmacokinetics of phenylpropanolamine hydrochloride (PPA HCl) from a Dexatrim controlled-release (CR) caplet and solution was studied. Each subject (n = 12) received either a 75 mg PPA HCl CR caplet once daily or a 25 mg PPA HCl solution given three times a day. All subjects received the medication for 4 consecutive days. On Day 1, the mean +/- SEM, AUC, tmax, and Cmax values were 1651 +/- 127 ng x h ml-1, 4.5 +/- 0.26 h and 143 +/- 13.5 ng ml-1, respectively, for the CR caplet and 1716 +/- 90.3 ng x h ml-1, 1.25 +/- 0.08 h and 126 +/- 5.8 ng ml-1 for the solution, respectively. At steady state (Day 4), the mean +/- SEM, AUC, tmax, and Cmax values were 1832 +/- 101 ng x h ml-1, 4.17 +/- 0.17 h and 151 +/- 6.5 ng ml-1, respectively, for the CR caplet and 2014 +/- 116 ng x h ml-1, 1.33 +/- 0.09 h and 143 +/- 8.7 ng ml-1, respectively, for the solution. The data from Day 1 were fitted to an oral one compartment model with a first order absorption rate constant, kA, first order elimination rate constant, k and lag time. The mean +/- SEM, kA, elimination half-life and lag time for PPA HCl from the CR caplet were 0.488 +/- 0.182 ng h ml-1, 5.84 +/- 1.66 h and 0.394 +/- 0.224 h, respectively. The mean +/- SEM, kA, elimination half-life and lag time for PPA HCl from the solution were 2.87 +/- 1.51 ng x h ml-1, 3.73 +/- 1.21 h, and 0.325 +/- 0.101 h, respectively. The smaller apparent kA and longer elimination half-life for PPA HCl from the CR caplet is due to the slow release of PPA HCl, thereby slowing its absorption producing sustained plasma drug concentrations. Blood pressures (supine and sitting) and heart rates measured at the time of blood sampling after the administration of the PPA HCl dosage forms demonstrated no clinically significant relationship between cardiovascular response and PPA HCl plasma concentration. These data demonstrate the bioavailability and pharmacokinetics of PPA HCl from a CR caplet and an immediate release solution.
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PMID:Bioavailability and cardiovascular safety of Dexatrim (phenylpropanolamine hydrochloride) from a controlled-release caplet. 226 37

The purpose of this study was to determine the intrinsic functions of the feline pylorus in vitro. The myoelectric and pressure characteristics of the intact pylorus, antrum, and duodenum, free of extrinsic hormonal or neural influences, were studied in an in vitro bath that allowed separation of the bathing medium surrounding the different bowel segments. Basal recordings revealed a zone of tonic high pressure of 28.4 +/- 3.5 mmHg (mean +/- SEM) at the pylorus. The basal slow wave frequencies in the pylorus and duodenum were 2.8 +/- 1.4 and 12.6 +/- 0.6 cycles/min, respectively. Spontaneous action potential-associated phasic contractions of the pylorus were noted in 38% of preparations. Enteric nerve stimulation with direct electric current (10 Hz, 1 ms, 10-50 V) applied proximal to the pylorus gave relaxation of the pylorus at the lower voltages and rebound excitation at higher voltages. Electrical stimulation distal to the pylorus yielded phasic contractile pyloric response during the entire stimulus. The duodenal instillation of 0.5 N HCl produced action potential-associated phasic contractions of the pylorus and duodenum but not the antrum. Pyloric responses to electrical stimulation or acidification were abolished by tetrodotoxin (10(-5) M). Bethanechol (10(-6) M) or substance P (10(-7) M) produced a contractile response at the site of stimulation but this response was not transmitted to include adjacent bowel segments. These studies suggest that the pyloric sphincter with its intrinsic reflex properties can be studied in vitro.
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PMID:Properties of the feline pyloric sphincter in vitro. 243 69

The purpose of this study was to investigate the state of the natural secondary caries and in vitro artificial secondary caries, associated with cast restorations cemented with zinc phosphate cement, histopathologically. For this study, the method of making and staining ground serial sections of teeth with cemented cast restorations was established. The material consisted of 50 extracted human permanent teeth with cemented cast restorations, and 12 human premolar teeth with in vitro secondary caries produced by the acid-gelatin system (pH 4.0). These specimens were embedded in MMA resin and then they were sliced to serial thin sections. Each section was etched by 0.1 N HCl, and stained with methylene blue fuchsin, and then observed with optical microscope, microradiography, and SEM. The result were as follows: 1. When the margin of restoration was set on dentine (cementum), the typical shape of natural secondary caries was found out. 2. The rate of natural secondary caries in case of margin set on dentine was about four times as many as the rate in case of margin set on enamel. 3. The shape of artificial secondary caries was very similar to the shape of natural secondary caries. 4. The resistance to secondary caries in case of the margin set on enamel was higher than the resistance in case of the margin set on dentine.
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PMID:[A study of secondary caries in cast restored teeth]. 248 74

Rat stomachs were studied after intragastrically administered, repeated doses of 0.1 N HCl, 100 mmol/l NaF, 50 mmol/l CaF2 in 0.1 N HCl, respectively. NaF produced extensive desquamation and cell injury, while CaF2 caused some desquamation and a slight decrease in secretory activity as revealed by light microscopic, SEM and TEM examinations.
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PMID:Comparison of the effects of NaF and CaF2 on rat gastric mucosa. A light-, scanning- and transmission electron microscopic study. 251 44

The surface structure of the connective tissue papillae (CP) of Suncus murinus tongue was observed by SEM after fixing with Karnovsky's fixative and removal of the epithelial cell layer with 3N or 8N HCl. On the surface of the slender conical tongue, there are densely distributed filiform papillae among which fungiform papillae are seen sporadically. A pair of vallate papillae are situated in the posterior region of the tongue. Filiform papillae appear somewhat different externally depending on the dorsal surface of the anterior tongue. At the tip of the tongue, filiform papillae are of a slender conical shape and have a slight depression in the anterior basal portion. The CP of these is seen as a spherical protrusion on which a shallow groove runs in the anteroposterior direction. In the middle region, somewhat large filiform papillae contain CP having one or two small round head-like structures on each spherical protrusion. These head-like structures are increased in number in the posterior region. In the most posterior region of the anterior tongue, there are distributed large filiform papillae having several slender protrusions that surround a basal anterior depression. These large branched filiform papillae have a glove finger like CP. Small conical filiform papillae are distributed in the posterior marginal region of the anterior tongue which have CP of a horse-shoe like protrusion that opens in the anterior direction. Spherical fungiform papillae have CP which are thick columnar in shape with many lateral thin folds running vertically and having a round depression on the top of each. CP of the vallate papillae appear as a beehive like structure.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Three dimensional structure of the connective tissue papillae of the tongue in Suncus murinus]. 251 78

Responsiveness of gonadotropes to GnRH depends, in part, on the number of plasma membrane GnRH receptors. Since the steady state level of these plasma membrane receptors is a function of the rates of both receptor generation (synthesis, unmasking, and recycling) and loss (internalization, degradation, and inactivation) we have sought to quantify the rate of synthesis of GnRH receptors in pituitary cell cultures. Further, since the protein kinase-C activator phorbol 12-myristate 13-acetate (PMA) has been shown to unmask a class of GnRH receptors that appear to be uncoupled from phosphoinositide turnover, we have measured the rate of synthesis of this second receptor population. The present studies use the density shift technique; incorporation of densely labeled amino acids confers a higher density to newly synthesized proteins and allows their separation by physical means. Cultures of pituitary cells were prepared from female weanling rats. After cells had attached to the culture dishes, medium was replaced at 12-h intervals with medium containing either densely labeled or normal amino acids. After the incubation, GnRH receptors were covalently linked to a photoaffinity receptor agonist [( 125I]Tyr5-[azido-benzoyl-D-Lys6-GnRH]), then solubilized with 1+ sodium dodecyl sulfate. In some cultures PMA (50 nM) was included during the photoaffinity agonist-binding step. Newly synthesized (dense) receptors were separated from previously synthesized receptors by velocity sedimentation (0-20% sucrose in 1% sodium dodecyl sulfate-10 mM Tris-HCl, pH 7.0; centrifuged at 156,000 x g for 24 h). Gradients were fractionated, and the radioactivity contained in each fraction was quantified. Newly synthesized GnRH receptors exhibited a higher density, as evidenced by further migration into the gradient, than did normal GnRH receptors. There was a delay of approximately 6 h between exposure to dense amino acids and the appearance of densely labeled GnRH receptors at the plasma membrane. Equilibrium for incorporation of dense amino acids into GnRH receptors was 48 h of exposure to dense amino acids. The time required for synthesis of half the entire population of GnRH receptors was 28 +/- 2 h (mean +/- SEM; n = 4). Scatchard analysis and the pattern of GnRH-stimulated LH release from densely labeled cells indicated that they bound the photoaffinity label (Kd = 0.4 nM; approximately 1 fmol receptor/microgram DNA) and secreted gonadotropin normally. Additionally, treatment with PMA caused a significant increase (181 +/- 24%) in photoaffinity agonist binding, consistent with previous observations.
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PMID:Synthesis of gonadotropin-releasing hormone receptors by gonadotrope cell cultures: both preexisting receptors and those unmasked by protein kinase-C activators show a similar synthetic rate. 254 92

To evaluate their chemical durability, samples of posterior composite resins were stored in NaOH (0.1 mol, 1 mol), HCl (0.1 mol, 1 mol), acetone (99%), and distilled water at 37 degrees C for a week and subjected to the direct tensile test, measurement of surface roughness and SEM observation. NaOH caused the degradation of composite resins, decrease of tensile strength and increase of surface roughness. The SEM photograph of fractured surface of tensile specimens revealed the degradation zone under the surface. It was considered that NaOH caused the hydrolysis of silan coupling of composite resins. HCl also caused the degradation of composite resins, but some resins showed the durability in this condition. More examination is needed to clarify the mechanism of degradation. Acetone caused the degradation of matrix resin and some composite resins. It was considered to dissolve the low degree of polymerized matrix resin of composite resins. Immersion in chemicals of composite resins was thought to be useful to evaluate the chemical durability and to accelerate the degradation in water.
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PMID:[Chemical durability of composite resins]. 260 92


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