Structure and developmental expression of the mouse CCK-B receptor gene.

Cholecystokinin (CCK) and gastrin exert their effects through two receptors, the CCK-A and CCK-B receptors. We have cloned the mouse CCK-B receptor gene (Cckbr) and determined its complete genomic structure, nucleotide sequence, and tissue-specific expression pattern. Cckbr is divided into five exons spanning 11 kb.

Microbiological transformation of enrofloxacin by the fungus Mucor ramannianus.

Enrofloxacin metabolism by Mucor ramannianus was investigated as a model for the biotransformation of veterinary fluoroquinolones. Cultures grown in sucrose-peptone broth were dosed with enrofloxacin. After 21 days, 22% of the enrofloxacin remained.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometric detection of bacterial biomarker proteins isolated from contaminated water, lettuce and cotton cloth.

Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectra of bacterial proteins were obtained from water, lettuce and cloth samples contaminated with Shigella flexneri, Escherichia coli, and Aeromonas hydrophila. Spectra were obtained using proteins directly isolated from water (or water used for rinsing samples) without culturing the bacteria. For S.

Liquid chromatographic analysis of incurred amoxicillin residues in catfish muscle following oral administration of the drug.

Improper application of antibiotic chemicals to livestock and aquaculture species may lead to the occurrence of residues in food supplies. An appropriate depletion period is needed after the administration of drugs to animals for ensuring that residues in edible tissues are below established tolerance levels. This study was conducted to determine incurred amoxicillin residues in catfish muscle following oral administration.

Modeling and optimization of anaerobic digested sludge converting starch to hydrogen.

The pH and hydraulic retention time (HRT) of a chemostat reactor were varied according to a central composite design methodology with the aim of modeling and optimizing the conversion of starch into hydrogen by microorganisms in an anaerobic digested sludge. Experimental results from 23 runs indicate that a maximum hydrogen production rate of 1600 L/m(3)/d under the organic loading rate of 6 kg starch m(3)/d obtained at pH = 5.2 and HRT = 17 h.

Development of methods for evaluating toxicity to freshwater ecosystems.

This article presents a summary of a collaborative research program involving five European research groups, that was partly funded by the European Commission under its Environmental Research Program. The objective of the program was to develop aquatic toxicity tests that could be used to obtain data for inclusion at Level 2 of the Risk Evaluation Scheme for the Notification of Substances as required by the 7th Amendment to EC Directive 79/831/EEC. Currently only a very limited number of test methods have been described that can be used for this purpose and these are based on an even smaller number of test species.

Murine prenatal expression of cholecystokinin in neural crest, enteric neurons, and enteroendocrine cells.

Cholecystokinin (CCK) is a regulatory peptide that is primarily expressed in two adult cell types: endocrine cells of the intestine and neurons of the central nervous system. To determine the ontogeny of CCK expression during intestinal organogenesis, we created a mouse strain in which the CCK gene was replaced by a lacZ reporter cassette using homologous recombination in embryonic stem cells. Initially, CCK expression in the developing intestine was limited to the myenteric plexus of the enteric nervous system.

Paradoxical pulmonary embolism secondary to aortocaval fistula: diagnosis by helical CT.

Spontaneous aortocaval fistula is an unusual but well recognized complication of abdominal aortic aneurysm. Reports of aortocaval fistula as the source of pulmonary embolism are rare. We report a case of paradoxical pulmonary embolism secondary to an aortocaval fistula.

Identification of bacterial proteins observed in MALDI TOF mass spectra from whole cells.

Characteristic ions in the MALDI TOF mass spectra from bacterial cells have been associated with four known proteins. The proteins, observed both from cells and in filtered cellular suspensions, were isolated by HPLC and identified on the basis of their mass spectra and their partial amino acid sequence, determined using the Edman method (10-15 residues). The acid resistance proteins HdeA and HdeB give rise to ions near m/z 9735 and 9060 in MALDI TOF mass spectra from cells and from extracts of both Escherichia coli 1090 and Shigella flexneri PHS-1059.

Regioselective transformation of ciprofloxacin to N-acetylciprofloxacin by the fungus Mucor ramannianus.

A strain of the saprobic fungus Mucor ramannianus, isolated from a forest, was used to demonstrate the potential for ciprofloxacin biotransformation by zygomycetes in the environment. The fungus carried out the regioselective N-acetylation of ciprofloxacin to a single product, which was purified from culture extracts by high-performance liquid chromatography. The metabolite was identified by mass and nuclear magnetic resonance spectrometry as 1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-(4-acetyl-1-piperazinyl)-3- quinolinecarboxylic acid.

Cellular and biochemical response of the human lung after intrapulmonary instillation of ferric oxide particles.

Bronchoalveolar lavage (BAL) was used to sample lung cells and biochemical components in the lung air spaces at various times from 1 to 91 d after intrapulmonary instillation of 2.6 microm-diameter iron oxide particles in human subjects. The instillation of particles induced transient acute inflammation during the first day post instillation (PI), characterized by increased numbers of neutrophils and alveolar macrophages as well as increased amounts of protein, lactate dehydrogenase, and interleukin-8 in BAL fluids.

A simple procedure for solid-phase synthesis of peptide nucleic acids with N-terminal cysteine.

Problems were encountered during attempts to prepare N-terminal cysteine-substituted peptide nucleic acids (PNAs) from commercially available, Fmoc-protected monomers. These problems have been surmounted by the use of an S-t-butylmercapto protecting group on the cysteine moiety. The solid-phase syntheses are carried out via a simplified procedure which should be generally useful for manual PNA synthesis.

Altered expression of selectable marker URA3 in gene-disrupted Candida albicans strains complicates interpretation of virulence studies.

The ura-blaster technique for the disruption of Candida albicans genes has been employed in a number of studies to identify possible genes encoding virulence factors of this fungal pathogen. In this study, the URA3-encoded orotidine 5'-monophosphate (OMP) decarboxylase enzyme activities of C. albicans strains with ura-blaster-mediated genetic disruptions were measured.

Result of angioplasty of brescia-cimino haemodialysis fistulae: medium-term follow-up.

Aim: To determine the results of transluminal angioplasty in patients with Brescia-Cimino arteriovenous fistulae.

Patients And Methods: Thirty-one patients underwent transluminal angioplasty of 36 stenotic lesions related to Brescia-Cimino arteriovenous fistulae over a 5-year period. The lesions treated were characterized by review of pre-angioplasty fistulograms.

Retention and intracellular distribution of instilled iron oxide particles in human alveolar macrophages.

Bronchoalveolar lavage (BAL) was used to sample retention of particles within the alveolar macrophage (AM) compartment at various times from 1 to 91 d following intrapulmonary instillation of 2. 6-microm-diameter iron oxide (Fe2O3) particles in human subjects. Particles were cleared from the lavagable AM compartment in a biphasic pattern, with a rapid-phase clearance half-time of 0.

Rapid confirmation of gene targeting in embryonic stem cells using two long-range PCR techniques.

Gene targeting in mouse embryonic stem (ES) cells generally includes the analysis of numerous colonies to identify a few with mutations resulting from homologous recombination with a targeting vector. Thus, simple and efficient screening methods are needed to identify targeted clones. Optimal screening approaches require probes from outside of the region included in the targeting vector to avoid detection of the more common random insertions.

Disruption of normal iron homeostasis after bronchial instillation of an iron-containing particle.

The atmosphere constitutes a prime vehicle for the movement and redistribution of metals. Metal exposure can be associated with an oxidative stress. We tested the hypothesis that, in response to an iron-containing particle, the human respiratory tract will demonstrate an increased expression of both lactoferrin and ferritin as the host attempts to transport and store the metal in a chemically less-reactive form and therefore diminish the oxidative stress the particle presents.

Inhibition of the membrane translocation and activation of protein kinase C, and potentiation of doxorubicin-induced apoptosis of hepatocellular carcinoma cells by tamoxifen.

Hepatocellular carcinoma (HCC) is characterized by high drug resistance to currently available chemotherapeutic agents. In a prospective clinical study, we have demonstrated that high-dose tamoxifen significantly enhanced the therapeutic efficacy of doxorubicin in patients with far-advanced HCC. In a search for a possible mechanism, we found that tamoxifen at a clinically achievable concentration (2.

Upregulation of tumor necrosis factor-alpha gene by Epstein-Barr virus and activation of macrophages in Epstein-Barr virus-infected T cells in the pathogenesis of hemophagocytic syndrome.

A potentially fatal hemophagocytic syndrome has been noted in patients with malignant lymphomas, particularly in EBV-infected T cell lymphoma. Cytokines, such as interferon-gamma (IFN-gamma), TNF-alpha, and IL-1alpha, are elevated in patients' sera. To verify whether infection of T cells by EBV will upregulate specific cytokine genes and subsequently activate macrophages leading to hemophagocytic syndrome, we studied the transcripts of TNF-alpha, IFN-gamma, and IL-1alpha in EBV-infected and EBV-negative lymphoma tissues.

Immunochemical, 32P-postlabeling, and GC/MS detection of 4-aminobiphenyl-DNA adducts in human peripheral lung in relation to metabolic activation pathways involving pulmonary N-oxidation, conjugation, and peroxidation.

4-Aminobiphenyl (ABP) is a recognized human bladder carcinogen, whose presence in cigarette smoke results in DNA adduct formation in the human urothelium. Since preliminary studies indicated that even higher levels of ABP-DNA adducts may be present in human peripheral lung, we utilized a sensitive immunochemical assay, in combination with 32P-postlabeling, to quantify the major 4-aminobiphenyl (ABP)-DNA adduct, N-(guan-8-yl)-ABP, in surgical samples of peripheral lung tissue from smokers and ex-smokers. No differences in adduct levels were detected between smokers and ex-smokers by immunoassay.

Molecular structure of the mouse CCK-A receptor gene.

We have cloned the mouse CCK-A receptor gene (Cckar), determined its nucleotide sequence, and analyzed its expression. The receptor protein is encoded in five exons distributed over 9 kb of genomic DNA. Intron/exon borders were determined by comparing the genomic nucleotide sequence with the mouse cDNA sequence obtained by reverse transcriptase polymerase chain reaction.

Genomic analysis of Epstein-Barr virus in nasal and peripheral T-cell lymphoma: a comparison with nasopharyngeal carcinoma in an endemic area.

The Epstein-Barr virus (EBV) is prevalent in nasal and peripheral T-cell lymphoma (NPTL) in Taiwan, where nasopharyngeal carcinoma (NPC) is endemic. In order to understand the pathogenesis of these two malignancies in this endemic area, genomic analysis of EBV in NPTL with comparison to NPC is important. We investigated the EBV subtype (types A and B), BamH-I "f" variant, and the Xho-I site mutant of the latent membrane protein-1 (LMP-1) gene in 19 cases of EBV-associated NPTL and in 30 cases of NPC.

Detection and confirmation of N-nitrosodialkylamines using liquid chromatography-electrospray ionization coupled on-line with a photolysis reactor.

Simultaneous detection and confirmation of several N-nitrosodialkylamines are accomplished by on-line coupling of a photolysis reactor with an HPLC-electrospray ionization mass spectrometer. Several parameters such as irradiation wavelength, irradiation time, mobile-phase composition, and pH, as well as different organic acid modifiers are investigated, and their impact on the detection of the N-nitrosodialkylamine-acid complex and its dissociative photolysis products is presented here. Additionally, the type of structural information obtained from the photolytic processes of N-nitrosodialkylamines is compared to that obtained by using in-source collision-induced dissociation.