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Biomedical subjects

F Jacobs

Publications and source records attributed to F Jacobs.

At least 55 records · Page 3Linked to original sources
PubMed1996

Immunohistochemical manifestations of unilateral kidney ischemia.

Events in the early post-transplant period have been correlated with increased renal allograft loss. Immunologic reactions and ischemic injury have been implicated in this process. While the immunologic aspects of allograft injury have been studied extensively, ischemic effects remain less well understood. To study the effects of ischemia in rats with different genetic backgrounds without the introduction of an alloimmune response, a clamp was placed on the vascular pedicle of the left kidney for 60 min. The short-term effects (1 wk) of ischemia were studied in groups of PVG (RT1c), LEW (RT1), DA (RT1a) and WR (RT1u) rats, Immunoperoxidase staining demonstrated limited infiltration of monocytes, macrophages, and T-cells accompanied by upregulation of low levels of MHC class II antigens on tubular epithelial cells, peritubular capillaries, and interstitial cells in kidneys of PVG and WF rats. Kidneys of LEW and DA rats had greater influxes of monocytes, macrophages, and T cells in addition to higher amounts of MHC class II antigens upregulation on tubular epithelium and interstitial cells. The long-term effects of ischemia were studied in kidneys of WF rats. These kidneys had a progressive increase in infiltrating T cells, monocytes, macrophages and MHC class II expression on the tubular epithelium and the interstitial cells at 14, 30, and 90 d after the ischemic insult. The differences in MHC class II expression between ischemic kidneys of PVG and LEW rats were not associated with differences in production of mRNA for IL-2, IFN-gamma, and TNF-alpha. In summary, transient renal ischemia in the absence of an allogeneic immune response triggers a progression of inflammatory responses, including leukocyte infiltration, cytokine production and MHC class II antigen upregulation which appears to be strain-dependent.

Animals↗
PubMed1995

Candida albicans septic thrombosis of the right atrium is associated with a central venous catheter.

Right atrial thrombus formation is a rare complication of central venous catheterization in adults. Infection of this thrombus is exceptional. A case of a right atrial thrombus associated with Candida albicans infection is described. Surgical thrombectomy, withdrawal of the catheter, and long-term antiinfectious therapy seem the only appropriate treatment. The literature on this unusual condition is reviewed.

Amphotericin B↗
PubMed1995

Vl-linker-Vh orientation-dependent expression of single chain Fv-containing an engineered disulfide-stabilized bond in the framework regions.

Single chain Fv fragments (scFv) derived from an antibody, MAb 174H.64 (Tru-ScintRSQ kit, Biomira), were constructed in both orientations, i.e. Vh-linker-Vl and Vl-linker-Vh, but only the latter form could be expressed and secreted in the recombinant Pichia pastoris system. The secreted scFv protein showed specific anti-idiotype binding activity. Additionally, the molecular graphic modeling has been used to identify a possible site for the introduction of an interchain disulfide bond in the framework region of Fv. These Cys-modifications of the sites were done using a method of PCR-mediated mutagenesis. The engineered protein (disulfide-stabilized Fv: dsFv) was expressed and tested for its binding activity. It was found that dsFv was as active as the corresponding scFv and more stable as determined by competitive radioimmunoassay.

Amino Acid Sequence↗
PubMed1994

Prevotella bivia as an unusual cause of endocarditis.

A case of monomicrobial endocarditis due to Prevotella bivia in a 60-year-old man without previous cardiac lesions is reported. The extremely indolent course with multiple systemic emboli as the only clinical manifestation occurring at least seven months before diagnosis and the persistently negative blood cultures were remarkable features of this case. The incidence, clinical characteristics, treatment and outcome of published cases of infective endocarditis due to anaerobic bacteria are briefly reviewed.

Bacteroides↗
PubMed1994

Toxocara canis infection presenting as eosinophilic ascites and gastroenteritis.

Eosinophilic ascites is rarely observed in clinical practice. It may be associated with the serosal type of eosinophilic gastroenteritis, abdominal lymphoma, hypereosinophilic syndrome, or peritoneal dialysis but is uncommonly related to parasitic infections. We report a case of a previously healthy young patient who developed diarrhea and exudative eosinophilic ascites. The final diagnosis was consistent with a parasitic infection due to Toxocara canis, while the clinical and radiological findings suggested an eosinophilic gastroenteritis. The diagnostic approach, especially parasitic serological data, which must be carefully interpreted, are discussed; in addition, the possible pathophysiological mechanisms involved in the production of ascites are evoked.

Adult↗
PubMed1994

Microbiological specimen collection in the emergency room.

The first step in the accurate diagnosis of infectious diseases is to provide the laboratory with adequate specimens for microbiological examination. The sample must be representative of the disease process: samples collected on body surfaces, harbouring saprophytic germ are less reliable than aspiration of closed body areas. A sufficient quantity of infectious material, preferably sampled with a syringe aspiration than with a swab, must be transported rapidly to the laboratory. Finally, close collaboration between the clinician and the microbiologist is essential for appropriate collection of selected specimens and corrected interpretation of the bacteriological results. Gram-stained smear examination of the samples is extremely useful and can provide immediate information for initiation of rational empiric antibiotic treatment. The indications for blood cultures sampling are reviewed. Number of blood cultures and volume of blood per culture are important. Screening of the sputum to discard samples too contaminated by the saliva is mandatory: if only screened samples are considered, a sputum Gram stain is a reliable guide to empiric therapy. Gram stain is also essential in the examination of the cerebrospinal fluid as well as is the detection of bacterial antigens. Cytological and chemical characteristics of this exudate are useful in differentiating bacterial meningitis from other diseases but there is considerable overlap between the laboratory parameters of bacterial meningitis and infections of other etiologies.

Blood↗
PubMed1993

Functional and chemical characterization of Hymenoptaecin, an antibacterial polypeptide that is infection-inducible in the honeybee (Apis mellifera).

As part of our ongoing search for novel antimicrobial agents and their use in singular or combined drug therapy, we have isolated a series of polypeptides from the lymph fluid of honeybees. These polypeptides are synthesized de novo, following experimental infection of the insect with live Escherichia coli cells, and confer a broad-spectrum antibacterial defense to the host. We have dissected this humoral "immune" system into its constituent components. In addition to the previously characterized apidaecins and abaecin, we also isolated a member of the defensin family of peptide antibiotics and, now, a novel 93-amino acid long, cationic polypeptide, termed hymenoptaecin. Detailed analysis established the complete chemical structure, including a 2-pyrrolidone-5-carboxylic acid at the N terminus, and indicated major differences with all known antibacterial polypeptides. Under physiological conditions, it inhibits viability of Gram-negative and Gram-positive bacteria, including several human pathogens. Lethal effects against E. coli are secondary to sequential permeabilization of outer and inner membrane. In combination, the six-constituent "peptide antibiotics" of bee lymph provide wide-spectrum antibacterial protection in vitro by virtue of complementarity rather than synergism.

Amino Acid Sequence↗
PubMed1993

Listeria monocytogenes hepatitis in a liver transplant recipient: a case report and review of the literature.

Listeria is an uncommon cause of hepatitis in adults. We report the case of a liver transplant recipient who presented with a clinical picture of acute hepatitis, 8 months after grafting. Blood cultures yielded Listeria monocytogenes. The patient made a full clinical recovery after adequate antimicrobial therapy (ampicillin and gentamicin intravenously for 4 weeks). Hepatitis was attributed to the Listeria infection. We believe this is the first reported case of Listeria hepatitis in an organ transplant recipient.

Hepatitis↗
PubMed1992

Genotypic and phenotypic methods for the investigation of a nosocomial Legionella pneumophila outbreak and efficacy of control measures.

To determine the source of a nosocomial outbreak of Legionella pneumophila serogroup 1 infection and the efficacy of control measures, clinical and environmental isolates were characterized by molecular subtyping and disease surveillance was conducted. The outbreak involved 32 cases (relative risk, 4.0; P less than .001 vs. previous period). Water colonization with L. pneumophila serogroup 1 and patients' exposure to faucet use incriminated the water system as the environmental source. Monoclonal antibody typing showed that patient isolates belonged mainly to type Pontiac and water isolates mainly to type Bellingham (P less than .001). By four genotypic techniques, outbreak-related isolates from patients and the water system were found to be clonally related and distinct from control strains (P less than .001). Heat and UV light treatment of the water system showed a protective efficacy of 88% (95% confidence interval, 75%-94%). These findings indicate that phenotypic variation may interfere with monoclonal antibody typing of legionellae and that waterborne legionellosis can be controlled by physical disinfection.

Belgium↗
PubMed1992

Cell-bound peptidase activities of Treponema denticola ATCC 33520 in continuous culture.

The oral spirochaete Treponema denticola ATCC 33520 was grown at a mean generation time of 10 h in anaerobic continuous culture in a serum- and carbohydrate-free medium at pH 7.0. The extracellular proteolytic activities of this spirochaete were then investigated by incubating washed cells with 68 2-naphthylamide derivatives of the Extended API System. Chymotrypsin-like, trypsin-like, elastase-like and iminopeptidase activities were demonstrated. The phenylalanine peptidase or chymotrypsin-like activity of T. denticola ATCC 33520, estimated with N-succinyl-L-phenylalanyl-L-leucyl-L-phenylalanine-thiobenzyl ester (SPLP) had a pH optimum at pH 8.5, a specific activity of 36.6 nmol min-1 (mg dry wt)-1 and was inhibited only slightly by HgCl2. The trypsin-like activity, estimated with benzoyl-DL-arginine-7-amido-4-methylcoumarin (BAMC), had a pH optimum at pH9, and a specific activity of 0.3 nmol min-1 (mg dry wt)-1; inhibition by HgCl2 indicated the involvement of active thiol groups. The activity should preferably be termed arginine peptidase activity, according to the carboxy-terminal amino acid of the test substrate. The extracellular proline peptidase activity, estimated with L-proline-7-amido-4-methylcoumarin. HBr (PRAMC), had an activity of 1.5 nmol min-1 (mg dry wt)-1, an optimum at pH 8.5 and the properties of a thiol protease. The main cell-bound and extracellular active peptidase activities of fast-growing cells of T. denticola ATCC 33520 are phenylalanine peptidase, proline peptidase, arginine peptidase and an oligopeptide-dependent alanine peptidase activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Aminopeptidases↗
PubMed1992

Spleen cell cytokine secretion in Mycobacterium bovis BCG-infected mice.

Three susceptible mouse strains, i.e., BALB/c (H-2d), C57BL/6 (H-2b), and major histocompatibility complex-congenic BALB.B10 (H-2b), were infected intravenously with 4 x 10(6) CFU of live Mycobacterium bovis BCG and analyzed 4 weeks later for in vitro spleen cell cytokine secretion in response to purified protein derivative (PPD), BCG culture filtrate (CF), BCG cellular extract, total BCG, the purified extracellular 30-32-kDa antigen (the fibronectin-binding antigen 85), or the intracellular 65-kDa heat shock protein. C57BL/6 and BALB.B10 mice produced 5- to 10-fold more gamma interferon and interleukin-2 (IL-2) when stimulated with CF, PPD, and antigen 85 than BALB/c mice did. When stimulated with BCG extract and whole BCG, gamma interferon and IL-2 levels were generally lower and comparable in the three strains. IL-4 was detected in spleen cell culture supernatants from infected BALB/c mice but not from C57BL/6 or BALB.B10 mice. IL-5 could not be detected. C57BL/6 and BALB.B10 spleen cells also produced more tumor necrosis factor alpha and IL-6 after stimulation with PPD and CF than BALB/c cells did. Finally, BCG vaccination generated efficient protective immunity in C57BL/6 and BALB.B10 mice but not in BALB/c mice. These data suggest that secreted mycobacterial CF antigens selectively induce a strong TH1 response in BCG-infected C57BL/6 and BALB.B10 mice, whereas in BALB/c mice this response is partly counterbalanced by TH2 cells.

Animals↗
PubMed1992

Mycoplasma hominis infection of perihepatic hematomas in a liver transplant recipient.

We report the case of a recipient of liver transplantation in whom postoperative perihepatic hematomas were infected by Mycoplasma hominis. Etiologic diagnosis was delayed because this organism is a rare cause of postoperative infection and usually does not grow on standard bacteriologic media. The role of M. hominis in postoperative infections and the diagnostic problems of this organism are discussed.

Hematoma↗
PubMed1991

Role of quinolones in the treatment of bronchopulmonary infections, particularly pneumococcal and community-acquired pneumonia.

In view of their antimicrobial activity and pharmacological properties, fluoroquinolones should be suitable for the treatment of lower respiratory tract infections. The overall clinical success rate using enoxacin, ofloxacin, pefloxacin, and ciprofloxacin ranges from 81% to 89%. Despite relatively high MICs of the fluoroquinolones for Streptococcus pneumoniae, the clinical success rate of these drugs in pneumococcal infections is 91%, but the eradication rate of this pathogen is lower (73%). In addition, fluoroquinolones appeared to be as effective as standard antibiotic regimens for treatment of bronchopulmonary infections in most of the comparative trials reported. The new quinolones could be a good alternative for treatment of acute exacerbations of chronic bronchitis, especially if examination of the sputum reveals gram-negative pathogens. In community-acquired pneumonia, drugs other than quinolones seem indicated because of the limited efficacy of the new quinolones in the treatment of severe pneumococcal infections and the poor activity of these drugs against the anaerobic flora causing aspiration pneumonia. In contrast, new quinolones should be very suitable for treatment of nosocomial pulmonary infections due to gram-negative pathogens. Quinolones used with or without erythromycin and rifampin, might be useful in the treatment of Legionnaires' disease. The role of these drugs in treatment of Chlamydia and Rickettsiae infections remains to be defined.

Anti-Infective Agents↗