[An unusual case of hepatic abscess]. / Ungewöhnliche Ursache eines Leberabszesses.

Right upper quadrant pain with chronic malaise and fever can be the clinical manifestation of a hepatic infection. An uncommon cause for the disease is hepatic actinomycosis. Actinomycosis was common in the preantibiotic era but is less frequent nowadays; consequently its timely recognition has become more difficult. The clinical and radiological findings often resemble other inflammatory and neoplastic lesions. We report a case of a mixed anaerobic liver abscess including fusobacteria and actinomycetes, without apparent predisposing factor. The diagnosis was obtained by CT-guided percutaneous aspiration of the hepatic mass, where microscopy revealed the presence of fusiform gramnegative bacteria and gram-positive branching filamentous rods consistent with Actinomyces species. The latter did not grow in culture, while the gram negatives were identified as fusobacterium nucleatum. The diagnosis of actinomycosis of the liver is confirmed in only a minority of cases by culture. The disease is usually treated with an extended course of antibiotics. Penicillin is the preferred choice.

Towards defining the urinary proteome using liquid chromatography-tandem mass spectrometry. II. Limitations of complex mixture analyses.

With an emphasis on obtaining a multitude of high quality tandem mass spectrometry spectra for protein identification, instrumental parameters are described for the liquid chromatography-tandem mass spectrometry analysis of trypsin digested unfractionated urine using a hybrid quadrupole-time-of-flight (Q-TOF) mass spectrometer. Precursor acquisition rates of up to 20 distinct precursors/minute in a single analysis were obtained through the use of parallel precursor selection (four precursors/survey period) and variable collision induced dissociation integration time (1 to 6 periods summed). Maximal exploitation of the gas phase fractionated ions was obtained through the use of narrow survey scans and iterative data-dependent analyses incorporating dynamic exclusion. The impact on data fidelity as a product of data-dependent selection of precursor ions from a dynamically excluded field is discussed with regards to sample complexity, precursor selection rates, survey scan range and facile chemical modifications. Operational and post-analysis strategies are presented to restore data confidence and reconcile the greatest number of matched spectra.

Towards defining the urinary proteome using liquid chromatography-tandem mass spectrometry. I. Profiling an unfractionated tryptic digest.

The proteome of normal male urine from a commercial pooled source has been examined using direct liquid chromatography-tandem mass spectrometry (LC-MS/MS). The entire urinary protein mixture was denatured, reduced and enzymatically digested prior to LC-MS/MS analysis using a hybrid-quadrupole time-of-flight mass spectrometer (Q-TOF) to perform data-dependent ion selection and fragmentation. To fragment as many peptides as possible, the mixture was analyzed four separate times, with the mass spectrometer selecting ions for fragmentation from a subset of the entire mass range for each run. This approach requires only an autosampler on the HPLC for automation (i.e, unattended operation). Across these four analyses, 1.450 peptide MS/MS spectra were matched to 751 sequences to identify 124 gene products (proteins and translations of expressed sequence tags). Interestingly, the experimental time for these analyses was less than that required to run a single two-dimensional gel.

Automated LC-LC-MS-MS platform using binary ion-exchange and gradient reversed-phase chromatography for improved proteomic analyses.

A simple multidimensional liquid chromatography system utilizing an isocratic pump and a HPLC system is described for the comprehensive proteomic analysis of complex peptide digest mixtures by coupled LC-LC-MS-MS techniques. A binary ion-exchange separation was achieved through the use of a strong cation-exchange column followed by a reversed-phase column for data-dependent LC-MS-MS analysis of the unbound analytes, and following salt elution (and concomitant column reequilibration), the bound analytes. Off-line validation of the platform showed near quantitative recovery of fractionated peptides and essentially complete ion-exchange partitioning. In comparative analyses of a highly complex peptide digest mixture a >40% increase in the number of peptide and protein identifications was achieved using this multidimensional platform compared to an unfractionated control.

Phase I clinical trial with HIV-1 gp160 plasmid vaccine in HIV-1-infected asymptomatic subjects.

The aim of the study was to investigate the safety of an HIV-1 gp160 plasmid vaccine. Four asymptomatic HIV-1-infected subjects with CD4+ lymphocyte counts >500/microl were injected with four times 400 microg of HIV-1 modified gp160 env and rev coding DNA vaccine at 0, 4, 10 and 28 weeks. Safety parameters, including autoimmune antibodies as well as CD4+/CD8+ cell counts and HIV-1 plasma concentrations, were monitored for 52 weeks after the first vaccine application. Follow-up data for more than 3 years are now available. The DNA vaccine proved to be safe and, specifically, did not induce anti-DNA autoimmune antibodies. Vaccination had no long-term effects on the CD4+/CD8+ lymphocyte counts, plasma HIV-1 RNA concentrations or disease progression. The present data supplement published data from Philadelphia, USA, where a dose-escalating study (30-300 microg) with the same HIV-1 DNA vaccine was performed.

FGF-18, a novel member of the fibroblast growth factor family, stimulates hepatic and intestinal proliferation.

The fibroblast growth factors (FGFs) play key roles in controlling tissue growth, morphogenesis, and repair in animals. We have cloned a novel member of the FGF family, designated FGF-18, that is expressed primarily in the lungs and kidneys and at lower levels in the heart, testes, spleen, skeletal muscle, and brain. Sequence comparison indicates that FGF-18 is highly conserved between humans and mice and is most homologous to FGF-8 among the FGF family members. FGF-18 has a typical signal sequence and was glycosylated and secreted when it was transfected into 293-EBNA cells. Recombinant murine FGF-18 protein (rMuFGF-18) stimulated proliferation in the fibroblast cell line NIH 3T3 in vitro in a heparan sulfate-dependent manner. To examine its biological activity in vivo, rMuFGF-18 was injected into normal mice and ectopically overexpressed in transgenic mice by using a liver-specific promoter. Injection of rMuFGF-18 induced proliferation in a wide variety of tissues, including tissues of both epithelial and mesenchymal origin. The two tissues which appeared to be the primary targets of FGF-18 were the liver and small intestine, both of which exhibited histologic evidence of proliferation and showed significant gains in organ weight following 7 (sometimes 3) days of FGF-18 treatment. Transgenic mice that overexpressed FGF-18 in the liver also exhibited an increase in liver weight and hepatocellular proliferation. These results suggest that FGF-18 is a pleiotropic growth factor that stimulates proliferation in a number of tissues, most notably the liver and small intestine.

Optimization of capillary chromatography ion trap-mass spectrometry for identification of gel-separated proteins.

The current paradigm for protein identification using mass spectrometric derived peptide-mass and fragment-ion data employs computer algorithms which match uninterpreted or partially interpreted fragment-ion data to sequence databases, both protein and translated nucleotide sequence databases. Nucleotide sequence databases continue to grow at a rapid rate for some species, providing an unsurpassed resource for protein identification in those species. Ion-trap mass spectrometers with their ability to rapidly generate fragment-ion spectra in a data-dependent manner with high sensitivity and accuracy has led to their increased use for protein identification. We have investigated various parameters on a commercial ion trap-mass spectrometer to enhance our ability to identify peptides separated by capillary reversed phase-high performance liquid chromatography (RP-HPLC) coupled on-line to the mass spectrometer. By systematically evaluating the standard parameters (ion injection time and number of microscans) together with selection of multiple ions from the full mass range, improved tandem mass spectrometry (MS/MS) spectra were generated, facilitating identification of proteins at a low pmol level. Application of this technology to the identification of a standard protein and an unknown from an affinity-enriched mixture are shown.

Alignment algorithm for homology modeling and threading.

A DNA/protein sequence comparison is a popular computational tool for molecular biologists. Finding a good alignment implies an evolutionary and/or functional relationship between proteins or genomic loci. Sequential similarity between two proteins indicates their structural resemblance, providing a practical approach for structural modeling, when structure of one of these proteins is known. The first step in the homology modeling is a construction of an accurate sequence alignment. The commonly used alignment algorithms do not provide an adequate treatment of the structurally mismatched residues in locally dissimilar regions. We propose a simple modification of the existing alignment algorithm which treats these regions properly and demonstrate how this modification improves sequence alignments in real proteins.

Comparison of in-gel and on-membrane digestion methods at low to sub-pmol level for subsequent peptide and fragment-ion mass analysis using matrix-assisted laser-desorption/ionization mass spectrometry.

The success of the mass spectrometric-based approaches for the identification of gel-separated proteins relies upon recovery of peptides, without high levels of ionization-suppressing contaminants, in solvents compatible with the mass spectrometer being employed. We sought to determine whether in-gel or on-membrane digestion provided a significant advantage when low to sub-pmol quantities of gel-separated proteins were analyzed by matrix-assisted laser-desorption/ionization mass spectrometry (MALDI-MS) with respect to the number and size of released peptides. Serial dilutions of five standard proteins of M(r) 17,000 to 97,000 (from 16 pmol to 125 fmol) were electrophoresed and subjected to in-gel digestion (using a microcolumn clean-up protocol, Courchesne, P.L. and Patterson, S. D., BioTechniques, 1997, in press) or on-membrane digestion following blotting to the PVDF-based membranes, Immobilon-P and Immobilon-CD. Peptide maps were able to be obtained for all proteins at the detection limit of each method (Immobilon-P and Immobilon-CD, 0.5 pmol; and in-gel, 125 fmol), and searches of Swiss-Prot or a non-redundant database (> 193000 entries) successfully identified all of the proteins, except beta-casein. Fragment-ion spectra using a curved-field reflector MALDI-MS were obtained from more than one peptide per protein at loads down to 250 fmol (except beta-casein). Using the uninterpreted data, a search of the nonredundant database and a six-way translation of GenBank dbEST (> 2,208,000 entries total) was able to identify myoglobin, carbonic anhydrase II, and phosphorylase b.

Prospective evaluation of a prognostic score for Pneumocystis carinii pneumonia in HIV-infected patients.

Serum lactate dehydrogenase levels, alveolar-arterial oxygen gradient, and percentage of neutrophils in bronchoalveolar lavage correlate most strongly with early mortality in Pneumocystis carinii pneumonia (PCP) in HIV-infected patients. However, the individual outcome can not be predicted by these parameters due to a considerable overlap between survivors and nonsurvivors. We prospectively investigated a PCP severity score, which has been developed earlier based on a retrospective analysis. Seven of 94 consecutively examined HIV-infected patients died within 14 days after diagnosis of PCP. A PCP severity score greater than 7 had a positive predictive value for early fatal outcome of 66.7 percent (6/9) and a negative predictive value of 98.8 percent (84/85). The overall diagnostic accuracy was 95.7 percent (90/94). The positive predictive value for early fatal outcome of a P(A-a)O2 > 35 mm Hg was 24 percent (6/25); the negative predictive value was 98.6 percent (68/69). However, the overall diagnostic accuracy was only 78.7 percent (74/94). The PCP severity score is a valuable tool for clinical decision making, for the early identification of patients with a prognostic unfavorable course, and for the comparison of patient populations in future studies of HIV-associated PCP.

An exogenous mouse mammary tumor virus with properties of Mls-1a (Mtv-7).

The classical minor lymphocyte stimulating (Mls) antigens, which induce a strong primary T cell response in vitro, are closely linked to endogenous copies of mouse mammary tumor viruses (MMTV). Expression of Mls genes leads to clonal deletion of T cell subsets expressing specific T cell receptor (TCR) V beta chains. We describe the isolation and characterization of a new exogenous (infectious) MMTV with biological properties similar to the Mls antigen Mls-1a. In vivo administration of either Mls-1a-expressing B cells or the infectious MMTV (SW) led to an increase of T cells expressing V beta 6 followed by their deletion. Surprisingly, different kinetics of deletion were observed with the exogenous virus depending upon the route of infection. Infection through the mucosa led to a slow deletion of V beta 6+ T cells, whereas deletion was rapid after subcutaneous infection. Sequence analysis of the open reading frames in the 3' long terminal repeat of both this exogenous MMTV (SW) and of Mtv-7 (which is closely linked to Mls-1a) revealed striking similarities, particularly in the COOH terminus, which has been implicated in TCR V beta recognition. The identification of an infectious MMTV with the properties of a strong Mls antigen provides a new, powerful tool to study immunity and tolerance in vivo.

Prevention of gram-negative shock and death in surgical patients by antibody to endotoxin core glycolipid.

The prophylactic effect of antibody to endotoxin core glycolipid was studied in surgical patients at high risk of gram-negative infection. At randomisation (on admission to intensive care unit), every 5 days thereafter, and at onset of septic shock, patients received plasma taken from donors before (control) or after immunisation with Escherichia coli J5, a mutant with only core determinants in its endotoxin. Gram-negative shock occurred in 15 of 136 controls and 6 of 126 J5 antibody recipients and related deaths in 9 of 136 and 2 of 126, respectively. J5 antibody was most effective in abdominal surgery patients, in whom shock occurred in 13 of 83 controls and 2 of 71 antibody recipients. Although antibody prophylaxis did not lower the infection rate, it prevented the serious consequences of gram-negative infections and thus improved the overall prognosis.

Variability of ceftriaxone pharmacokinetics in hospitalized patients with severe infections.

The pharmacokinetic behavior of ceftriaxone was studied in 60 patients with severe community- or hospital-acquired infections. Serum concentrations one to three hours after a 30-minute intravenous infusion appeared to be dose related. The mean two-hour levels were 110, 138, and 146 mg/liter, and trough values averaged 54.9, 28.5, and 16.1 mg/liter after doses of 1.0, 2.0, and 3.0 g, respectively. At 24 hours, values were at least 10 mg/liter in all but seven patients. The serum half-life of ceftriaxone in all patients and for all dosage regimens varied from 3.5 to 59.4 hours. In patients with normal renal function (serum creatinine 1.30 mg/dl or less) the mean half-life was 8.2 hours. In patients with moderate (creatinine 1.34 to 1.83 mg/dl) and severe (creatinine 2.40 mg/dl or greater) renal insufficiency, the mean serum half-lives were 12.8 and 12.4 hours, respectively. In six patients who had severe renal failure and concomitant hepatic dysfunction, half-lives ranged from 23.7 to 59.4 hours. Single daily doses of 2.0 g of ceftriaxone produced adequate serum concentrations. Dose reductions are recommended in patients with both renal and hepatic dysfunction.