Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C1275122 (TEM)
 21,810 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A technique for the formation of sheep erythrocyte (E) rosettes in frozen human tissue sections is reported. The labile nature of the receptor for E rosettes on lymphocytes requires the use of controlled conditions for tissue processing and the reaction with indicator cells. The distribution of E rosettes in sections of normal human thymus, lymph nodes, tonsils, and spleens was comparable to that of the T marker-positive cells identified by immunofluorescence with the specific anti-human T cell serum. There with no overlap with areas positive for 19S EAC and 7S EA rosettes. Erythrocytes treated with a sulfhydryl reagent, 2-aminoethylisothiuronium bromide (AET), and with neuraminidase formed better rosettes in sections than did untreated erythrocytes. E rosettes in tissue sections can determine changes in the distribution of T cells in different lymphoproliferative and infiltrating disorders.
 ...
PMID:Localization of human T lymphocytes in tissue sections by a rosetting technique. 32 25

A dimethylbarbituric acid reagent has been used to follow the kinetics of loss of two water-soluble carbodiimides, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and the structurally related 1-ethyl-3-(4-azonia-4,4-dimethylpentyl) carbodiimide (EAC), in aqueous solution as a function of pH and added chemical reagents. In 50 mM 2-(N-morpholino)ethanesulfonic acid at 25 degrees C, EDC has t1/2 values of 37, 20, and 3.9 h at pH 7.0, 6.0, and 5.0, respectively, while the corresponding values for EAC are 12, 2.9, and 0.32 h. Iodide, bromide, or chloride, at 0.1 M, has very little or no effect on carbodiimide stability. However, 0.1 M glycine methyl ester or 0.1 M ethylenediamine causes a significant increase in the rate of loss of EAC and EDC, while the presence of 0.1 M phosphate, 0.1 M hydroxylamine, or 0.01 M ATP decreases the half-lives to less than or equal to 0.4 h at all pH values.
 ...
PMID:Stability of water-soluble carbodiimides in aqueous solution. 215 46

Multiresistant Klebsiella pneumoniae strains isolated from three patients in the same intensive care unit were more resistant to ceftazidime than to cefotaxime and aztreonam but remained susceptible to moxalactam and imipenem. Resistance to beta-lactams, kanamycin, streptomycin, sulfonamides, and tetracyclines was transferable to Escherichia coli by conjugation and was lost en bloc after treatment with ethidium bromide. Agarose gel electrophoresis of wild types and transconjugants indicated that these resistances were mediated by a 150-kilobase plasmid, pCFF14. The strains constitutively produced a beta-lactamase with isoelectric point close to 5.6 and which had a higher Vmax for ceftazidime and cephalothin than for cefotaxime. The substrate profile and isoelectric point of this enzyme thus differ from those of other known plasmid-mediated beta-lactamases, including the broad-spectrum enzyme CTX-1. Hybridization studies support the derivation of the novel enzyme from a TEM-type beta-lactamase.
 ...
PMID:Novel plasmid-mediated beta-lactamase in clinical isolates of Klebsiella pneumoniae more resistant to ceftazidime than to other broad-spectrum cephalosporins. 329 23

Sacs of the stripped and everted, isolated descending rat colon were incubated for 2 hours in presence of the following surfactants at the mucosal side: Dodecylsulphate (DDS), dioctylsulphosuccinate (DOSS), cetrimonium bromide (CTMAB), Triton X100 and deoxycholic acid (DOC). After tissue fixation, the sacs were processed for light microscopy (LM) and for scanning (SEM) and transmission (TEM) electron microscopy. All three methods revealed that DOSS (1.3 X 10(-4) and 2.6 X 10(-4) mol/l, CTMAB (5 X 10(-5) and 1 X 10(-4) ) and Triton (2 X 10(-5), 5 X 10(-5) and 1 X 10(-4) ) caused only minor or moderate changes compared to parallel controls, as did also DDS at 1 X 10(-5) and 2 X 10(-5) mol/l. DDS at 2 X 10(-4) and 4 X 10(-4) mol/l and DOC at 1.5 X 10(-4) and 3 X 10(-4) mol/l caused more prominent changes. LM showed swollen, vacuolated cells with pycnotic nuclei; many of these cells seemed to be extruded. According to SEM, cells thus affected were most abundantly localized to the normal extrusion zone at the borders of the crypt-surface epithelial cell units. DOC tended to cause a more generalized affection within the units than DDS. In spite of these deleterious effects, gaps corresponding to missing epithelial cells were not observed. TEM indicated the mechanism responsible for restoration of epithelial continuity in spite of extensive cell loss: The remaining epithelial cells seemed to flatten out and re-establish cell-to-cell contact by pseudopod formation along the basement lamina. This repair mechanism seemed to operate at a rapid rate; however, incomplete closure of cellular gaps i.e. small denuded parts of the basement lamina were occasionally observed. The results of this study are discussed in relation to a functional study under identical experimental conditions (Gastroenterol. Clin. Biol. 1981, 5, 124), in which these surfactants caused a significant alteration of normal colonic transport function.
 ...
PMID:Studies on hydragogue drugs: light and electron microscopic examination of the isolated rat colonic mucosa exposed to deoxycholic acid and synthetic surfactants. 670 65

Mononuclear cell infiltrates in thyroid gland tissue sections from patients with drug-treated Graves' disease (n = 5), non-toxic nodular goiter (n = 12) and papillary carcinoma (n = 5) were characterized by immunological membrane receptors. T lymphocytes were identified using 2-aminoethylisothiouronium bromide hydrobromide (AET)-treated sheep erythrocytes (E) (E-AET). E sensitized with rabbit IgM antibodies (A) and human complement (C) (EAC) were used to detect receptors for C3b (B lymphocytes and monocytes) or C3d (B lymphocytes). E sensitized with rabbit IgG antibodies were used to detect receptors for the Fc portion of IgG (FcR; lymphocytes and monocytes). The results indicate that T and B lymphocytes infiltrate the thyroid gland in Graves' disease as well as in nodular goiter. T lymphocytes seemed to predominate in both disorders. In thyroid papillary carcinoma the number of B and T lymphocytes was negligible. However, EA absorbed strongly to sections from 3 of the 5 tumors studied, indicating the presence of FcR on tumor cells or infiltrating host cells. The percentage of active and total T lymphocytes in peripheral blood from the patients with drug-treated Graves' disease was markedly reduced (9 +/- 5 and 28 +/- 11%, controls 22 +/- 9 and 68 +/- 11%; p less than 0.01 and less than 0.001). In patients with nodular goiter the percentage of total T lymphocytes was slightly, but significantly decreased (p less than 0.05). We suggest that the marked decrease in blood T lymphocytes observed in Graves' disease might be caused by the drug therapy. In nodular goiter the predominance of T lymphocyte infiltration together with a slight decrease in blood T lymphocytes suggest that autoimmune mechanisms are involved in the pathogenesis.
 ...
PMID:Immunological characterization of mononuclear cells in thyroid gland and blood in Graves' disease, multinodular goiter and papillary carcinoma. 689 2

Lymphocytes from heparinized or defibrinated blood were separated on Lymphoprep and washed in phosphate-buffered saline (PBS) or Hanks' balanced salt solution (HBSS). Defibrination caused a decreased yield of lymphocytes compared to heparin treatment. The cell loss was probably non-selective, as only minor differences in lymphocyte subpopulations were found. However, lymphocytes from defibrinated blood, washed in PBS gave a lower percentage of rosette-forming cells (RFC) in most tests, and higher number of latex-phagocytizing cells. For the stabilization of sheep erythrocyte (E)-RFC, treatment of E with 2-amino-ethylisothiouronium bromide hydrobromide (AET), with addition of fetal calf serum (FCS), and E-RFC without FCS fixed with glutaraldehyde gave similar results, and higher percentages of RFC than the RFC test performed with FCS. Storage of whole blood or separated lymphocytes for 24 h at 4 degrees C generally resulted in a reduction in the percentages of E-RFC, particularly active E-RFC, but not of EA- or EAC-RFC. The ranges of the results were usually wider after storage.
 ...
PMID:Technical aspects of rosette tests for the demonstration of lymphocyte subpopulations. 708 Aug 38

The vesicle-to-micelle transformation has been investigated thus far in lipid + surfactant systems where the vesicle-forming lipid is chemically very different from the micelle-forming surfactant. The dimeric surfactants, alkanediyl-alpha, omega-bis(dimethyldodecylammonium bromide), are known to form vesicles when the alkanediyl spacer is long enough (for instance, spacer = eicosanediyl, referred to as 12-20-12) and spheroidal micelles for shorter spacers (spacer = decanediyl, referred to as 12-10-12). These surfactants together with the conventional surfactant dodecyltrimethylammonium bromide (DTAB) permitted us to study the transformation of the 12-20-12 vesicles into micelles on addition of the chemically similar micelle-forming DTAB and 12-10-12. Spectrophotometry (light absorbance measurements), video-enhanced light microscopy, and transmission electron microscopy at cryogenic temperatures (cryo-TEM) were used to study the transformation at different scales of aggregate size. Electrical conductivity, which probes the system at the atomic scale (free counterions), was also used. Absorbance measurements showed the transformation to occur between 1.8 and 2.8 wt% added surfactant at a constant 12-20-12 concentration of 1.4 wt%. Light microscopy showed the progressive solubilization of the larger vesicles. Cryo-TEM showed that the initial effect of DTAB addition was to reduce the size of the vesicles, whereas 12-10-12 addition resulted in the formation of multilamellar vesicles. Further additions of either surfactant reduced the size of the vesicles, then brought about the formation of spheroidal micelles until complete solubilization of the vesicles. The giant threadlike micelles seen in previous studies of vesicle-to-micelle transformation in lipid/surfactant systems were never observed with the systems investigated. The conductivity results also revealed differences in behavior on additions of DTAB and 12-10-12.
 ...
PMID:Vesicle-to-Micelle Transformation in Systems Containing Dimeric Surfactants 905 7

Phosphoprotein appears to play an important role in the mineralization of dentin during tooth development and remineralization after demineralization by dental caries. To better understand this role, we describe the extraction and characterization of phosphoprotein from immature, human root apex dentin during and after EDTA demineralization. The extraction procedure included dissociation of the demineralized dentin matrix by guanidine hydrochloride (Gdn.HCl) followed by subsequent digestion with cyanogen bromide (CNBr) and collagenase. Characterization of these extracts included 'Stains-All' staining of SDS polyacrylamide gels (SDS-PAGE) and amino acid, protein and phosphorus analyses. The ability of these matrices to remineralize was determined by TEM and measuring calcium levels in the remineralized tissue by atomic absorption spectroscopy. The staining of SDS-PAGE gels and amino acid analysis showed that an intact phosphophoryn was extracted from the dentin of the immature apices during EDTA demineralization and that it had an apparent Mr approximately 140,000. In the subsequent extracts and digests, the phosphoprotein has a range of molecular weights, some of which may have been degraded products of the intact phosphoprotein. A greater quantity of phosphoprotein was found in the EDTA-demineralized dentin matrices than in dentin after Gdn.HCl, CNBr and collagenase digests. These EDTA-demineralized matrices also remineralized to a greater extent than those dissociated with Gdn.HCl. The differences in both the quantity and the quality, as defined by the amino acid residue profile, of the phosphoprotein in the sequential extracts of the root apex dentin may be important in affecting the ability of this tissue to remineralize.
 ...
PMID:Phosphoprotein analysis of sequential extracts of human dentin and the determination of the subsequent remineralization potential of these dentin matrices. 970 61

The purpose of this study was to investigate the effects of 316L stainless steel (SS) corrosion products on the in vitro biomineralization process, because tissue necrosis, bone loss, impaired bone mineralization, and loosening of orthopedic implants are associated with ions and debris resulting from biodegradation. Rat bone marrow cells were cultured in experimental conditions that favored the proliferation and differentiation of osteoblastic cells and were exposed to SS corrosion products obtained by electrochemical means for periods ranging from 1 to 21 days. Quantification of total and ionized Ca and P, as well as Fe, Cr, and Ni, ions in the culture media of control and metal added cultures during the incubation period was performed to study the influence of corrosion products on the Ca and P consumption that occurs during the mineralization process. Control cultures and metal effects on cultures were evaluated concerning DNA content, enzymatic reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), and alkaline phosphatase (ALP) activity. Histochemical detection of ALP, Ca, and phosphate deposition, and examination of the cultures by scanning and transmission electron microscopy (SEM and TEM) were also performed. The presence of SS corrosion products resulted in impairment of the normal behavior of rat bone marrow cultures. Levels of Cr and Ni in the medium of cultures exposed to 316L SS corrosion products decreased throughout the incubation period, suggesting a regular deposition of these species; these results were supported by TEM observation of the cultures. Cultures exposed to the corrosion products presented lower DNA content, MTT reduction, and ALP activity and failed to form mineralized areas. These cultures showed negative staining on histochemical reactions for the identification of calcium and phosphate deposition and SEM and TEM examination did not show mineral globular structures or mineralization foci, respectively, which is characteristic of cultures grown in control conditions. These results suggest that metal ions associated with 316L SS are toxic to osteogenic cells, affecting their proliferation and differentiation.
 ...
PMID:Decreased consumption of Ca and P during in vitro biomineralization and biologically induced deposition of Ni and Cr in presence of stainless steel corrosion products. 977 16

Genetically engineered spider dragline silk protein was modified to incorporate methionines flanking the beta-sheet forming polyalanine regions. The methionines could be selectively chemically oxidized and reduced. This chemical change altered the bulkiness and charge of the sulfhydryl groups, and in turn, the beta-sheet forming tendencies of the polyalanine domains and solubility of the protein. The genes encoding these redesigned proteins were constructed, cloned and expressed in Escherichia coli. In the reduced state (beta-mercaptoethanol) the approximately 25 kDa protein behaved similarly to native spider dragline silk, crystallizing into beta-sheets based on diffraction analysis and appearing fibrous by TEM. The addition of the methionines into the consensus dragline silk sequence did not disrupt the normal macromolecular assembly behavior of the protein. In the oxidized state (phenacyl bromide) the protein did not form beta-sheet crystals and appeared morphologically featureless based on TEM. A reduction in beta-strand content was also observed upon oxidation based on FTIR and TEM analysis and confirmed by X-ray diffraction analysis. To further confirm changes in assembly behavior observed for the recombinant protein containing the methionines, a model peptide with the same repeat amino acid sequence was synthesized and characterized. Shifts in molecular weight, observed by MALDI, along with corresponding changes in crystallinity, by electron diffraction, agreed with the changes expected on activation and deactivation of the redox trigger. These results support the use of a redox trigger as a useful feature with which to control the assembly of beta-sheet forming proteins.
 ...
PMID:Reduction-oxidation control of beta-sheet assembly in genetically engineered silk. 1171 Jan 78


1 2 3 4 5 6 7 8 9 10 Next >>