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Biomedical subjects

R Fleischmann

Publications and source records attributed to R Fleischmann.

At least 37 records · Page 2Linked to original sources
PubMed1995

[Do proton pump inhibitors after endoscopic control of acute ulcer hemorrhage have an advantage over H2 receptor antagonists?].

During a two year period (1992-1993) we investigated whether or not, after endoscopic therapy of bleeding ulcers, the suppression of gastric acid secretion with an administration of a proton pump blocker (Omeprazol) is more effective than the administration of H2-receptor antagonist (Ranitidin) with respect to prevention of recurrent bleeding episodes, frequency of surgical intervention and mortality. 106 patients (64 men, 42 women) were treated with the proton pump blocker and 126 patients (82 men, 44 women) received the H2-receptor antagonist. Patients were treated either with an initial dose of 80 mg Omeprazol followed by 3 x 40 mg Omeprazol i.v. or with a daily dose of 3 mg/kg body weight Ranitidin i.v. No significant differences could be detected between the two treatment regimes with respect to the parameters mentioned above. Rebleeding which could be controlled by endoscopic hemostasis occurred in 19.8% vs. 17.5% (Omeprazol/Ranitidin) of patients. Surgical intervention because of rebleeding was necessary on 8.5% vs. 8.7% of the patients. Mortality due to hemorrhage was 5.7% vs. 4.0%. From these results we conclude that, following endoscopic hemostasis of bleeding ulcers, Omeprazol has no advantage over Ranitidin using our dosage regimes.

Adult↗
PubMed1994

Bacterial expression of Chinese hamster regulatory type-I and catalytic subunits of cyclic AMP-dependent protein kinase and mutational analysis of the type-I regulatory subunit.

The type-I regulatory subunit (RI) of the cyclic AMP-dependent protein kinase (PKA) from Chinese hamster ovary (CHO) cells has been cloned and expressed in a strain of BL21(DE3) Escherichia coli lacking adenylate cyclase [BL21(DE3)/delta cya]. RI expressed in this bacterial system free of cyclic AMP is soluble and can reconstitute functional PKA. Recombinant CHO C alpha is predominantly insoluble with some active soluble protein. C beta is entirely insoluble and inactive. Soluble recombinant RI and soluble recombinant C alpha can associate in vitro and be activated by cyclic AMP. Six site-directed mutations of RI were generated to study the interaction of cyclic AMP with RI and RI-C alpha subunit interactions. Four cyclic AMP-binding-site point mutants were generated [W261R (tryptophan to arginine at position 261), a novel mutation in site A; V376G, a novel mutation in site B; G200E (site A), and Y370F (site B), previously described in bovine RI were introduced into the CHO RI for comparison purposes]. Mutants W261R, Y370F, and G200E demonstrated decreased 8-N3-[3H]cyclic AMP binding as well as 5-fold reduced affinity for [3H]cyclic AMP, with threefold increased EC50 values for cyclic AMP activation of kinase activity from reconstituted mutant holoenzymes. The mutation at V376G did not alter cyclic AMP binding or activation by cyclic AMP of mutant holoenzyme. A truncation mutant, G200Stop, which lacks both cyclic AMP-binding sites, did not bind cyclic AMP but can inhibit C alpha subunit activity. A novel mutation outside the cyclic AMP-binding regions of RI (V89A) weakened the interaction with C alpha indicated by a 7-fold lower EC50 for mutant holoenzyme activation by cyclic AMP.

Amino Acid Sequence↗
PubMed1994

Healing of NSAID-induced gastric ulcers with a synthetic prostaglandin analog (enprostil).

OBJECTIVE: Conventional ulcer therapy has not been proven effective in healing gastric ulcers caused by nonsteroidal anti-inflammatory drugs (NSAIDs) if the NSAIDs are continued. Our objective in this study was to determine whether a prostaglandin analog is an effective treatment for such NSAID-induced lesions. METHODS: To make this determination, we conducted a 9-wk double-blind trial comparing placebo with enprostil 35 micrograms twice daily and three times daily. Use of antacids was not allowed. Three centers entered 145 patients with chronic inflammatory arthritis and osteoarthritis, mean age 63 yr, who required continuous fixed-dose NSAID therapy within the range of therapeutic dosage. The minimum entrance criterion was the presence of either four gastric erosions or one gastric ulcer. Two pretreatment endoscopies within a 2-wk interval were performed to establish the presence of stable baseline gastric lesions. Endoscopy was repeated at wk 6 and 9 during treatment. All groups were similar with regard to age distribution, sex, weight, height, smoking usage, and alcohol consumption. RESULTS: The ulcer healing rates were 14%, 57%, and 68% at 6 wk and 19%, 68%, and 74% at 9 wk for the groups receiving placebo, enprostil twice daily, and enprostil three times daily, respectively (p < 0.01). Complete mucosal healing of all erosions and ulcers at 9 wk occurred in 59% of enprostil-treated patients and in 10% of placebo-treated patients. Additional gastric erosions and gastric ulcers developed in 16% of placebo patients and 4% of the enprostil patients. Eighteen percent of enprostil patients withdrew early from the study due to adverse experiences, such as diarrhea and abdominal pain. CONCLUSION: We concluded that during continued NSAID therapy 1) enprostil 35 micrograms (taken either twice daily or three times daily) heals NSAID-induced gastric ulcers and erosions and protects the mucosa from further NSAID-induced gastric injury; 2) gastric ulcers and erosions rarely heal spontaneously, and 3) enprostil results in a high incidence of diarrhea.

Aged↗
PubMed1993

Cloning, genomic organization, and chromosomal localization of human cathepsin L.

Cathepsin L is a lysosomal cysteine protease whose expression and secretion is induced by malignant transformation, growth factors, and tumor promoters. Many human tumors express high levels of cathepsin L, which is a broad spectrum protease with potent elastase and collagenase activities. Two published human cathepsin L cDNA sequences differ only in their 5'-untranslated regions. In this study, we demonstrate the concurrent expression of two distinct human cathepsin L mRNAs (hCATL-A and hCATL-B) in adenocarcinoma, hepatoma, and renal cancer cell lines. Cloning of the human cathepsin L gene by polymerase chain reaction amplification of genomic DNA and subsequent sequencing reveals that hCATL-A and hCATL-B mRNAs are encoded by a single gene. The 3' end of the first intron contains the 5' portion of hCATL-B and is contiguous to the second exon of the gene. These data suggest either the possibility of alternative splicing or the presence of a second promoter within the first intron of the hCATL gene. We mapped the hCATL gene to chromosome 9q21-22. Sequencing of both the mouse and human cathepsin L genes demonstrates almost complete conservation of exon and intron position, but significant divergence in intron structure, possibly reflecting differences in regulation of expression of the mouse and human cathepsin L genes.

Amino Acid Sequence↗
PubMed1993

Analysis of the primary structure of insulin-like growth factor binding protein-3 cDNA from Werner syndrome fibroblasts.

The mRNA encoding insulin-like growth factor binding protein-3 (IGFBP-3) is equally overexpressed in late-passage (old) normal human diploid fibroblasts (HDF) and in HDF derived from individuals with the premature aging disorder Werner syndrome (WS), relative to early-passage (young) normal HDF. However, the accumulation of IGFBP-3 protein in medium conditioned by WS cells is substantially less than in medium of old cells. In an attempt to understand this disparity between mRNA levels and protein output, we determined the nucleotide sequence of IGFBP-3 cDNA isolated from a WS cDNA library derived from mRNA of WS HDF, and compared it to three published normal IGFBP-3 DNA sequences. In the open reading frame, our results differed from one of the three sequences by a glycine substitution for alanine at residue 32. Minor differences in the 3'-untranslated region between the WS cDNA sequence and all three of the normal DNA sequences were also detected as 12 individual base substitutions and one adenine insertion. Thus, dampened accumulation of IGFBP-3 in medium conditioned by WS cells is not due to significant alterations in the sequence of the cognate mRNA.

Amino Acid Sequence↗
PubMed1991

The long-term U.S. study--a report on outcome and tolerance.

Altogether 1,912 patients have been enrolled in studies of nabumetone in the United States. They were all patients with osteoarthritis or rheumatoid arthritis. After completing participation within randomised studies patients were entered into an open study which continued for up to five years. These cases provide longterm efficacy and safety data for the use of nabumetone. About 25% of patients were withdrawn because of lack of efficacy; most of these withdrawals were in the first year of therapy. There was a similar picture with side-effects. About 12% of patients were withdrawn, mostly in the first year. Many patients continued to take nabumetone for five years without adverse effects and with continuing efficacy. The numbers of patients in whom nabumetone was stopped due to lack of efficacy or an adverse reaction was similar in those aged over 65 years and in patients aged less than 65 years. These results show that nabumetone is a safe and effective anti-inflammatory drug in long term clinical use.

Aged↗
PubMed1990

A report of three multiclinic trials evaluating arbaprostil in arthritic patients with ASA/NSAID gastric mucosal damage. The Upjohn Company Arbaprostil ASA/NSAID Gastric Mucosal Damage Treatment Study Groups.

Three randomized, placebo-controlled multiclinic trials involving arbaprostil dosages of (a) 10 micrograms; (b) 25 micrograms; and (c) 10, 25, or 50 micrograms orally for 4 wk in patients older than 18 yr with rheumatoid arthritis or osteoarthritis who had endoscopically documented nonsteroidal antiinflammatory drug-associated gastric mucosal damage were conducted in the United States. All patients continued taking the nonsteroidal antiinflammatory drugs and were reendoscoped after 4 wk of therapy. Success at that time was defined as complete resolution of all gastric mucosal damage. Six hundred fifty-eight patients were enrolled in the three trials. Significantly more patients experienced healing in the arbaprostil treatment groups in all trials compared with those who received placebo. The healing rates in the various trials were 68% and 32% (10 micrograms vs. placebo; p = 0.007); 77% and 23% (25 micrograms vs. placebo; p less than 0.001); and 52%, 46%, 35%, and 16% (50, 25, and 10 micrograms vs. placebo; p less than 0.001, less than 0.001, and 0.002, respectively). Diarrhea, mostly of a mild nature, was the only arbaprostil-associated side effect and was found with the 25- and 50-microgram dosages (33% and 59%, respectively). No exacerbation of arthritis signs or symptoms was found. Arbaprostil at doses with varying effects on gastric acid secretion (25 and 50 micrograms) was documented in these trials to be an effective and safe agent for healing gastric mucosal damage associated with aspirin or other nonsteroidal antiinflammatory drugs in patients with either rheumatoid arthritis or osteoarthritis without adversely affecting joint symptomatology.

Administration, Oral↗
PubMed1990

A missing consideration: the psychiatric patient classification for scheduling-staffing systems.

The psychiatric nursing department at a university teaching hospital identified the need to develop a management tool to systematically and objectively determine resource requirements (staffing) for unique psychiatric patient populations. A classification methodology was needed for budget development, trending, productivity monitoring, and potentially developing a rich data base for nursing research. A study of existing classification systems found them to be limited for use in psychiatric settings. The psychiatric nursing department designed and implemented a patient classification tool based on biopsychosocial needs manifested by psychiatric patients in acute care settings.

Hospitals, Teaching↗
PubMed1989

T-cells inhibit Friend murine leukemia virus infection of B-cells in vitro.

The ability of splenic T-cells to regulate Friend murine leukemia virus replication in lipopolysaccharide-activated target B-cells infected in vitro was investigated. Removal of the T-cell fraction from spleen cells resulted in an 8- to 10-fold enhancement in the number of productively infected cells in the remaining B-cell-enriched fraction, as compared with unseparated spleen cells, and the addition of increasing numbers of purified T-cells to isolated B-cells prior to infection resulted in a directly proportional reduction in the number of B-cells releasing infectious progeny virus. Separation of splenic T-cells into Lyt 2- and Lyt 2+ T-cells before addition to infected B-cell cultures resulted in inhibition of infection only with the Lyt 2- T-cells; Lyt 2+ T-cells did not inhibit infection, even at high 1:1 ratios. Similarly, separation of splenic T-cells into L3T4+ and L3T4- T-cells before addition resulted in inhibition by L3T4+ but not L3T4- T-cells. Also, cytotoxic treatment of splenic T-cells with monoclonal anti-L3T4 antibody and complement before addition to B-cell cultures destroyed the regulatory effects. Finally, depletion of macrophages from both T-cells and B-cells before infection and coculture had no effect on the ability of T-cells to regulate B-cell infection. Collectively these results demonstrate that L3T4+ T-cells can inhibit Friend murine leukemia virus replication in target B-cells. Culture of isolated splenic T-cells with Friend murine leukemia virus in vitro resulted in the induction of alpha/beta but not interferon-gamma synthesis and in some experiments interferon-containing supernatants from T-cell-virus cultures were able to mediate suppression of B-cell infection with Friend helper virus; the addition of antibody specific for interferon-alpha/beta to cultures inhibited the ability of T-cells to regulate B-cell infection.

Animals↗
PubMed1986

Induction of cytochrome P-448 iso-enzymes and related glucuronyltransferases in the human liver by cigarette smoking.

Human liver 10-20 mg from biopsy samples removed for diagnostic purposes from selected patients has been used for the preparation of microsomes. The activity of certain mono-oxygenases and UDP-glucuronyltransferases, as well as certain other enzymes involved in drug metabolism, has been determined using different substrates as indicators. Smokers oxidized benzo(a)pyrene and 7-ethoxyresorufin and also conjugated alpha-naphthol at a significantly increased rate compared to non-smokers. This indicates induction of certain mono-oxygenases and glucuronyltransferases which differs from the induction produced by phenobarbital. The findings can account for the reduced activity and increased elimination rate of certain drugs prescribed to smokers.

Benzopyrene Hydroxylase↗
PubMed1986

Independent regulation of the antiviral states induced by MuIFN-alpha/beta and by MuIFN-gamma.

The stability profiles of the antiviral states induced in L-929 cells against mengovirus by murine interferons MuIFN-alpha/beta and by MuIFN-gamma were shown to be different. Treatment of cells with combinations of IFN-alpha/beta and IFN-gamma have previously been shown to result in a potentiated expression of the antiviral state. Here we report studies of the stabilities of the antiviral states induced by various combinations of IFN-alpha/beta and IFN-gamma and that the regulation of the antiviral states induced by IFN-alpha/beta and IFN-gamma were independent of each other.

Animals↗
PubMed1986

Molecular genetic analysis of cAMP-dependent protein kinase.

Genetic evidence has been obtained indicating that the responsiveness of CHO cells to cAMP requires an intact cADepPK system. DNA carrying mutant RI and C subunit genes has been transferred to wild-type cells. Recipient cells carrying the DNA have been detected by selecting for expression of the phenotype for cAMP resistance. We are in the process of cloning a functional mutant RI subunit to use as a moveable genetic element that can confer cAMP resistance on recipient cells. This cloned gene should allow us to test hypotheses concerning the mechanism of cAMP regulation of transcription in mammalian cells.

Animals↗
PubMed1985

DNA-mediated gene transfer of a mutant regulatory subunit of cAMP-dependent protein kinase.

We have used DNA-mediated gene transfer of genomic DNA to introduce into wild-type Chinese hamster ovary (CHO) cells a mutant gene that confers resistance to the growth inhibitory effect of cAMP. This dominant mutation in CHO cell line 10248 is responsible for an alteration in the RI subunit (RI*) of the type I cAMP-dependent protein kinase (Singh, T. J., Hochman, J., Verna, R., Chapman, M., Abraham, I., Pastan, I.H., and Gottesman, M.M. (1985) J. Biol. Chem. 260, 13927-13933). The transformant 11564 which was studied in detail, has the same characteristics as the original mutant 10248 including continued growth in medium containing 8-Br-cAMP, an increase in the Ka for cAMP activation of the kinase, a greatly reduced amount of type II protein kinase activity, an altered incorporation of the photoaffinity label 8-N3[32P]cAMP into the RI* subunit of PKI, and an absence of cAMP-dependent phosphorylation of a Mr = 52,000 protein in intact cells. In addition, analysis of the DNA of the transformant indicates the presence of an increased amount of DNA for the RI gene. These results are consistent with the transfer of a mutant gene for the RI* subunit of the cAMP-dependent protein kinase and its phenotypic expression in the transformant and also support the hypothesis that the mutation responsible for the defect in cell line 10248 is due to an alteration in the gene for RI.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1985

Interindividual variations in the activities of cytosolic and microsomal epoxide hydrolase in human liver.

Mammals have at least two epoxide hydrolases (EHs) with a broad significance in drug metabolism. One enzyme is localized in the endoplasmic reticulum and other membranes (EHm), and the other is in the cytosol (EHc). In the present study we found that humans differ greatly in the activities of these enzymes in liver. The specific activities in microsomes from 166 subjects (most of them patients suffering from hepatic diseases), measured with benzo[a]pyrene 4,5-oxide as the substrate, varied by a factor of 63. The activities in the cytosol, determined with trans-stilbene oxide as substrate varied 539-fold among 135 subjects. A subdivision into different diagnostic groups showed an increase in EHm activity (1.7-fold control) but not EHc activity in tuberculosis patients treated with rifampicin, ethambutol and isoniazid. No other diagnostic group showed significantly altered EH activities. Furthermore the activities did not differ between females and males, alcoholics and non-alcoholics or smokers and non-smokers. In the 77 subjects where both EHc and EHm activities were determined, no correlation between them was observed, indicating separate biological control.

Cytosol↗
PubMed1984

Drug metabolism in man and its relationship to that in three rodent species: monooxygenase, epoxide hydrolase, and glutathione S-transferase activities in subcellular fractions of lung and liver.

Activities of drug metabolizing enzymes were determined in subcellular fractions of lung biopsies from 12 human subjects and in liver biopsies from 15 other human subjects. Monooxygenase (MO) activity with 7-ethoxycoumarin as a substrate and epoxide hydrolase (EH) activity with benzo[a]pyrene 4,5-oxide as a substrate were measured in the microsomal fraction, glutathione S-transferase (GST) activity toward 2,4-dinitrochlorobenzene in the cytosolic fraction. MO activity was further characterized by the use of inhibitors known to act preferentially on different MO forms. To facilitate extrapolations from test results obtained in animals to man enzyme activities were also determined in corresponding fractions from commonly used laboratory animals, Sprague-Dawley rat, NMRI mouse, and Syrian golden hamster. All investigated specific activities were lower in lung than in liver preparations by factors ranging from 2.4 to 7 in the mouse, 4 to 18 in rat and hamster, and 11 to 697 in man. The high ratio between liver and lung activity in man occurred with MO and is due to an extremely low activity in human lung. It is not clear whether this low activity is predominantly due to low amounts of enzyme or to inhibitors known to be present in human lung preparations. With this exception of human lung MO, species differences in the investigated enzyme activities were moderate. Among the three rodent species, rat was most similar to man, with none of the investigated activities differing by a factor more than 2. The mouse differed from these two species by considerably higher MO and GST activities in both organs, and by a relatively low EH activity in liver for the investigated substrates, while the hamster displayed comparatively high lung GST and EH and liver GST and MO activities. MO inhibition patterns by different in vitro inhibitors were similar in the same organs of different species, but differed in lung and liver. Standard concentrations of the diagnostic inhibitors led to preferential inhibition of lung MO by metyrapone and considerably less by tetrahydrofuran, while for liver MO the reverse was true. In both organs, the standard concentration of alpha-naphthoflavone had only very weak effects. In conclusion, man and commonly used laboratory rodents are not grossly different with respect to the investigated enzyme activities with the possible exception of lung MO. For the substrates investigated, the rat represented clearly the best model for man among the studied animal species.

Adult↗
PubMed1984

Abnormality of insulin binding and receptor phosphorylation in an insulin-resistant melanoma cell line.

The insulin receptor possesses an insulin-stimulated tyrosine-kinase activity; however, the significance of receptor phosphorylation in terms of the binding and signaling function of the receptor is unclear. To help clarify this problem, we have studied insulin binding and receptor phosphorylation in a Cloudman S91 melanoma cell line and two of its variants: the wild type (1A) in which insulin inhibits cell growth, an insulin-resistant variant (111) in which insulin neither stimulates or inhibits growth, and a variant (46) in which insulin stimulates cell growth. 125I-insulin binding to intact cells was similar for the wild-type 1A and insulin-stimulated variant 46. The insulin-resistant variant 111, in contrast, showed approximately 30% decrease in insulin binding. This was due to a decrease of receptor affinity with no major difference in receptor number. When the melanoma cells were solubilized in 1% Triton X-100 and the insulin receptor was partially purified by chromatography on wheat germ agglutinin-agarose, a similar pattern of binding was observed. Phosphorylation was studied by incubation of the partially purified receptor with insulin and [gamma-32P]ATP, and the receptor was identified by immunoprecipitation and NaDodSO4 PAGE. Insulin stimulated phosphorylation of the 95,000-mol-wt beta-subunit of the receptor in all three cells types with similar kinetics. The amount of 32P incorporated into the beta-subunit in the insulin-resistant cell line 111 was approximately 50% of that observed with the two other cell lines. This difference was reflected throughout the entire dose-response curve (10(-9) M to 10(-6) M). Qualitatively similar results were obtained when phosphorylation was studied in the intact cell. Peptide mapping of the beta-subunit using tryptic digestion and reverse-phase high-performance liquid chromatography column separation indicated three sites of phosphorylation in receptor from the wild type and variant 46, but only two major sites of phosphorylation of variant 111. These data suggest that the insulin-resistant variant melanoma 111 possesses a specific defect in the insulin receptor which alters both its binding and autophosphorylation properties, and also suggests a possible role of receptor phosphorylation in both the binding and the signaling function of the insulin receptor.

Binding, Competitive↗