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Biomedical subjects

E Reich

Publications and source records attributed to E Reich.

At least 91 records · Page 5Linked to original sources
PubMed1989

[In vivo contact angle measurements on filling materials before and after surface polishing].

The adhesion of oral bacteria on teeth and filling materials is a function of the surface energy and consequently the contact angle of a drop of fluid on the respective material. This study determines the contact angle on various filling materials (composites, glass ionomere cement) before and after surface polishing. Thirty and sixty minutes after application of the filling materials composites demonstrated contact angles which partly were significantly smaller than on natural enamel. Glass ionomere cements did not show any significant differences from enamel. After surface polishing, one composite material and one glass ionomere cement showed significantly larger contact angles than before. Further studies are required to elucidate the clinical relevance of different contact angles.

Chemical Phenomena↗
PubMed1989

[Efficiency of follow-up programs in periodontal patients--review of the literature].

Follow-up programs for periodontally treated patients may largely prevent loss of teeth and attachment. Consequently they are an indispensable part of periodontal treatment. The success of treatment hinges on the recall interval which should be determined individually (to 6 month for most patients), as well as on diagnosis and treatment, which need to be modified in accordance with the specific requirements of the follow-up. It is under discussion whether individual parts of the follow-up program should be handled by adequately trained assistant staff.

Follow-Up Studies↗
PubMed1989

Fission 99Mo/99mTc Generators--a study of their quality.

Quality was controlled of seven different 99Mo/99mTc generators sold in the Federal Republic of Germany, which were all loaded with fission molybdenum. Aim of the work was to test the 99mTc eluates for their radionuclidic and radiochemical purity. Furthermore, the 99Mo content of the aluminium oxide column was measured. Determination of the elution efficiency, measurement of the pH-value of the eluate as well as a test to detect soluble aluminium in the eluate were also performed. In addition to the chemical and physical examinations, application, quality of accessories and their practicability were tested at all generators. The methods of analysis chosen were, among others, gamma spectrometry and thin-layer chromatography; the measuring methods were a site-sensitive proportional counter (measurement of the distribution of radioactivity of the chromatograms) and atomic absorption spectrometry (Al content of the eluates). The quality control of the 99mTc eluates had satisfying results. The eluates showed - with one exception - high and sufficient radionuclidic purity and very good radiochemical purity. A considerable overload of the columns with 99Mo at the time of reference was not found. The elution yields with values between 85 and 122% were in good agreement with the requirements. All eluates had pH-values between 5.0 and 6.5, and an aluminium content below 1 microgram/ml. The generators had good performance and proved generally to be a reliable source of 99mTc-pertechnetate. The application was safe and, with some exceptions, fulfilled the requirements.

Germany, West↗
PubMed1987

The murine urokinase-type plasminogen activator gene.

The murine urokinase-type plasminogen activator (uPA) gene has been isolated from a BALB/c liver DNA cosmid library and its nucleotide sequence established. The gene is organized into 11 exons comprising 34.7% of the 6710 base pair (bp) region spanning the interval between the presumed transcription initiation and polyadenylation sites. The transcription initiation site is flanked by common RNA polymerase II promoter elements, including a TATA box and a potential transcription factor Sp1 binding site. A large polypurine tract of the structure (AG)22(AGGG)16(AG)28 is located 79 bp upstream of the 5'-terminus. It was highly sensitive to the single-strand-specific nuclease S1, suggesting a non-B-DNA conformation of unknown significance. Consistent with the well-documented influence of adenosine cyclic 3',5'-phosphate (cAMP) on uPA gene expression, there is a dodecanucleotide homologous to proposed regulatory sequences identified in other cAMP-modulated genes. Comparison of the murine uPA gene to the previously described porcine and human uPA genes revealed an unusually high degree of evolutionary (interspecies) sequence conservation that was not limited to exons but included introns and flanking sequences as well.

Amino Acid Sequence↗
PubMed1987

An inhibitor of plasminogen activation from human placenta. Purification and characterization.

Placental extracts contain inhibitors of human urinary urokinase. These extracts form a heterogeneous population of complexes with 125I-urokinase that are recognizable by changes in gel filtration profile and mobility during sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Treatment with reducing agents eliminated the size heterogeneity without loss of activity, thereby allowing the placental inhibitor to be purified. Active inhibitor has been isolated in apparently homogeneous form after an eight-step procedure that included salt extraction, ammonium sulfate fractionation, column chromatography on CM-cellulose, DEAE-Sepharose, and hydroxylapatite, chromatofocusing, preparative gel electrophoresis, and hydrophobic chromatography. The purified inhibitor has Mr = 47,000. The inhibitor is relatively specific for plasminogen activators since it does not inhibit the action of plasmin, factor XIIa, plasma kallikrein, or thrombin. The inhibitor forms complexes with 1:1 stoichiometry that block the active sites of urokinase (but not prourokinase) and both one- and two-chain forms of tissue plasminogen activator. The stability of these complexes in sodium dodecyl sulfate-polyacrylamide gel electrophoresis suggest that they are based on covalently bonded structures. Although both types of plasminogen activator are inhibited, the rate of interaction is significantly faster with urokinase, tissue plasminogen activator being inhibited less efficiently. The complexes formed can be dissociated by mild alkali or hydroxylamine, thereby regenerating both enzymes and inhibitor at their original molecular weights. The results suggest that the complexes are stabilized by ester-like bonds; these might involve the hydroxyl of serine at the active site of the proteases and a carboxyl group in the inhibitor.

Amino Acids↗
PubMed1987

Laparoscopic treatment of tubal pregnancy.

Seventeen tubal pregnancies were treated successfully with a laparoscopic procedure over the past four years. Four different laparoscopic techniques were used: salpingectomy, partial salpingectomy (midtube resection), fimbrial expression, and salpingotomy. "Preventive hemostasis" using vasopressin has made salpingotomy our treatment method of choice. Ruptured tubal pregnancy was not considered a contraindication to laparoscopic treatment. Four of the six women who were trying to conceive and were followed for longer than six months have had documented intrauterine pregnancies; one woman subsequently developed a contralateral tubal pregnancy which was treated by laparoscopic salpingotomy. Tubal ectopic pregnancy, even in the presence of rupture, can be managed effectively by a variety of laparoscopic techniques with benefits including minimal incision, short hospitalization, early return to full activity, and in many cases, a patent tube.

Fallopian Tubes↗
PubMed1987

Prenatal diagnosis of minute 5p- deletion: a cytogenetic problem in detection.

An unbalanced translocation, 46,XX,der(5)t(5;11) (p15;q25)mat was ascertained by prenatal diagnosis. The mother previously had a liveborn child with cri du chat syndrome. The subtlety of the chromosome rearrangement in this case illustrates the need for the most detailed cytogenetic investigations in cri du chat cases when deletion or translocation are not immediately obvious.

Adult↗
PubMed1986

Isolation of a mutant LLC-PK1 cell line defective in hormonal responsiveness. A pleiotropic lesion in receptor function.

A mutant LLC-PK1 cell line, M18, was isolated after a single treatment of the parent culture with N-methyl-N'-nitro-N-nitroso-guanidine. In contrast to LLC-PK1 cells, the mutant did not exhibit production of urokinase-type plasminogen activator (uPA) in response to the hormones calcitonin and vasopressin, but produced the expected levels of uPA upon stimulation by the receptor-independent adenylate cyclase activators forskolin and cholera toxin, as well as by the phosphodiesterase inhibitor isobutylmethylxanthine and the 8-bromo analogue of adenosine cyclic monophosphate, Br8cAMP. The patterns of activation of cAMP-dependent protein kinase were identical to those of uPA induction: calcitonin and vasopressin were without effect, but the response to all other agents was normal. In similar fashion, mutant cell homogenates displayed normal activation of adenylate cyclase upon treatment with sodium fluoride, forskolin, or the non-hydrolyzable GTP analogue guanosine 5'-[beta, gamma-imino]triphosphate, but were unresponsive to calcitonin or vasopressin. The ability of M18 cells to bind radioactively labelled calcitonin and vasopressin was measured. The mutant possessed less than 4% of the normal levels of the receptor binding activity for both hormones. Somatic cell hybrids formed between M18 and LLC-PK1 cells were found to retain normal hormone binding activity and responsiveness to hormones, indicating that the defect in M18 cells was recessive. M18 was concluded most probably to contain a single mutation impairing the function of two distinct polypeptide hormone receptors.

Adenylyl Cyclases↗
PubMed1986

The human tissue plasminogen activator gene.

The nucleotide sequence of the human tissue plasminogen activator (t-PA) gene has been established. A total of 36,594 base pairs (bp) was sequenced; this included 32,720 bp from the site of initiation of transcription to the polyadenylation site, in addition to 3,530 and 344 bp of 5' and 3' flanking DNA, respectively. Thirteen intervening sequences divide the gene into 14 coding regions; the size range for exons is 43-914 bp, while that for introns is 111-14,257 bp. The gene and 5' flanking region contain 28 copies of Alu repetitive DNA and a single KpnI repeat. The transcription initiation site was identified by S1 nuclease, exonuclease VII, and primer extension analysis as an A residue; "TATA" and "CAAT" boxes are located in the expected positions upstream of this proposed site. Results of the analysis of the gene sequence and its comparison with data banks are described. The protein and gene structures of tissue and urokinase plasminogen activator are compared; based on these features the evolutionary relationship of the two human plasminogen activators appears to be close.

Amino Acid Sequence↗
PubMed1986

Chemical, radiochemical, and radionuclide purity of eluates from different commercial fission 99Mo/99mTc generators.

Seven 99Mo/99mTc generators (using fission 99Mo) obtained from seven different manufacturers were studied in 1984 and 1985 to test the quality of the eluates. We present the findings concerning the elution efficiency, radionuclide purity, 99Mo breakthrough, radiochemical purity, pH, and aluminium content of the eluates. One generator was overloaded with 99Mo by about 40%, while one generator had 99mTc yields of only about 80%. The eluates generally (although with some exceptions) exhibited a high and satisfactory radionuclidic purity and good radiochemical purity. The low-level determination of 99Mo breakthrough using a commercially available dose calibrator with a 99Mo assay shield indicated a misleadingly high 99Mo content. All of the eluates had pH values of between 5.0 and 5.5, and the aluminium content was always below the detection limit of 1 microgram per milliliter of eluate. The generators performed well and proved their capability of functioning as reliable sources of sodium pertechnetate Tc99m. In all cases, the pertechnetate produced met the requirements of the European Pharmacopeia.

Quality Control↗
PubMed1986

Radiochemical purity and in vitro stability of commercial hippurans.

Good radiochemical purity of hippuran is important regarding the patient's radiation dose, primarily because of the high thyroid exposure from free iodide. The radiochemical purity and in vitro stability of 11 commercially available 131I, 125I, and 123I hippurans were analyzed by means of thin layer chromatography. Three different radioactive impurities were found in all hippuran samples: (a) free radioiodide, (b) a radiochemical impurity that has been unknown up until now, and (c) labeled o-iodobenzoic acid. Quality control of several hippurans with regard to radiochemical purity gave evidence of considerable differences during storage. The lowest amount of free-iodide was 0-0.6% in a hippuran preparation from one manufacturer, the highest amount 0.8-4.6% in a sample from another manufacturer. Hippuran samples from four other manufacturers were found to contain greater than 2% of free iodide prior to their expiration date.

Aged↗
PubMed1985

Chromosomal locations of human tissue plasminogen activator and urokinase genes.

A panel of human-mouse somatic cell hybrids and specific complementary DNA probes were used to map the human tissue plasminogen activator and urokinase genes to human chromosomes 8 and 10, respectively. This result is in contrast to a previous assignment of a plasminogen activator gene to chromosome 6. As neoplastic cells produce high levels of plasminogen activator, it is of interest that aberrations of chromosome 8 have been linked to various leukemias and lymphomas and that two human oncogenes, c-mos and c-myc, have also been mapped to chromosome 8.

Animals↗
PubMed1985

Induction and desensitization of plasminogen activator gene expression by tumor promoters.

Tumor promoting phorbol esters and mezerein strongly induced plasminogen activator (urokinase, uPA) synthesis in porcine kidney cell cultures (LLC-PK1). Induction was due to increased uPA-mRNA levels which rose from 10 to 300 molecules/cell within 2 h of exposure to 16 nM phorbol myristate acetate. We have compared the action of tumor promoters with that of 8-bromo-cAMP, another potent inducer of uPA; the similarities between the two kinds of induction were: both involved transcriptional activation of the uPA gene; both were rapid in onset, changes in transcription rate being detectable within 10-20 min; the initial rates of transcription and uPA-mRNA accumulation were substantial and in the same order of magnitude; neither class of inducer required protein synthesis to stimulate uPA transcription. The main contrast between the two types of agents was that the uPA response to tumor promoters was transient whereas that to cAMP compounds was sustained: cultures rapidly lost their response to tumor promoters within 2 h after initial exposure while retaining responsiveness to cAMP-related agents. The cells developed a specific drug-induced desensitization which was slowly reversed after tumor promoters were removed from the culture medium. Since protein kinase C is now well established as the receptor for phorbol-derived and several other tumor promoters it will be of interest to determine whether desensitization occurs at the level of receptor.

8-Bromo Cyclic Adenosine Monophosphate↗