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Biomedical subjects

E Jacobs

Publications and source records attributed to E Jacobs.

At least 19 recordsLinked to original sources
PubMed1996

Are outbreaks and sporadic respiratory infections by Mycoplasma pneumoniae due to two distinct subtypes?

Thirty-seven clinical isolates of Mycoplasma pneumoniae, cultured from patients' respiratory material between 1986 and 1994, were typed by immunological methods and by polymerase chain reaction (PCR). For immunological typing two monoclonal antibodies (mAb) were used that recognized the P1 adhesion of Mycoplasma pneumoniae strain FH but differed in their ability to inhibit the adherence of Mycoplasma pneumoniae to erythrocytes. The mAb P1.58, which was not able to inhibit adherence, showed reactions with all patients' isolates in immunoblots, whereas the adherence-inhibiting mAb P1.62 reacted with only seven patients' isolates. Due to variations within the P1-adhesin genome of Mycoplasma pneumoniae group 1 (Mycoplasma pneumoniae type strain M129) and group 2 (Mycoplasma pneumoniae type strain FH), two primer sets were designed. According to the size of the PCR-amplification products, all clinical isolates that showed no mAb P1.62 reactivity belonged to Mycoplasma pneumoniae group 1, whereas mAb P1.62-positive-reacting mycoplasma isolates were characterized as group 2 strains. During an outbreak of Mycoplasma pneumoniae diseases in 1992, all 19 clinical isolates showed no cross-reactivity in immunoblots with the mAb P1.62 and were typed by PCR as Mycoplasma pneumoniae group 1 strains. Furthermore, 206 Mycoplasma pneumoniae complement fixation test-positive patient sera (titer > 1:40) from the study period were tested for adherence-inhibiting antibodies towards both type strains. Thirty-two sera showed adherence-inhibiting antibodies towards group 1 and 22 towards group 2 mycoplasmas. In only seven sera were adherence-inhibiting antibodies directed to both Mycoplasma pneumoniae groups. The serological data of the outbreak in 1992 revealed that patients with Mycoplasma pneumoniae group 1 infections developed adherence-inhibiting antibodies more frequently than did patients infected with group 2, which might have implications for the pathogenesis of Mycoplasma pneumoniae diseases and subsequent infections.

Adolescent↗
PubMed1995

Production of lipidated meningococcal transferrin binding protein 2 in Escherichia coli.

Neisseria meningitidis strains grown under iron starvation conditions produce transferrin binding proteins (Tbp1 and Tbp2) which have been shown to play a major role in iron acquisition. Recent studies performed with Tbp2 purified from N. meningitidis suggest that this surface protein is a potential vaccine component. In order to further evaluate the immunogenicity of Tbp2, it was essential to develop a heterologous expression system to generate high amounts of purified protein. Tbp2 is produced in Neisseria as a precursor with a signal peptide whose cleavage follows a lipidation step on a cysteine residue which is the first amino acid in the mature protein. When produced in Escherichia coli with its natural signal peptide, a high amount of Tbp2 (about 10% of total cell proteins) was detected. However, most of the protein was nonlipidated precursor and only a small fraction was mature Tbp2. In order to optimize the maturation of the precursor, the natural signal sequence was replaced by several E. coli lipoprotein signal peptides. Expression levels and maturation of the precursor were highly variable depending on the signal peptide used. With one of these, an efficient maturation and a high amount of mature lipidated Tbp2 were obtained (about 3% of total cell proteins). A large-scale production process was then established for this E. coli-produced Tbp2.

Amino Acid Sequence↗
PubMed1995

Molecular mimicry by Mycoplasma pneumoniae to evade the induction of adherence inhibiting antibodies.

Specific regions of adherence binding sites and epitopes of the P1 adhesin of Mycoplasma pneumoniae were synthesised as octapeptides and used as targets in a modified enzyme-linked immunosorbent assay. Acute phase and convalescent sera from 10 patients with M. pneumoniae infection were tested for antibody reactivity to these octapeptides. In convalescent sera, antibody activities were directed against octapeptides of the epitope regions, whereas no antibody activity was found in acute or convalescent sera to octapeptides of adherence-mediating binding sites could be explained partially from the results of cross-reactivity experiments with adherence-inhibiting anti-P1 adhesin monoclonal antibodies (MAbs). Two of these MAbs showed cross-reactions with intracellular antigens of eukaryotic cell lines in immunofluorescence microscopy experiments. The cross-reacting antigens were isolated and characterised as glyceraldehyde-3-phosphate dehydrogenase and 2-phospho-D-glycerate hydrolyase. Antigenic mimicry of eukaryotic structures by functional sites of the P1 adhesin of M. pneumoniae may influence the pathogenesis of M. pneumoniae infection.

Adhesins, Bacterial↗
PubMed1995

The satellite laboratory and point-of-care testing. Integration of information.

Laboratory testing is returning to the point of care, where it started in the 19th century. This decentralization of testing is occurring because of the many advantages it brings to the practice of critical care medicine, such as faster turn-around time and better patient management in inpatient and outpatient settings. However, decentralization of testing is decentralizing laboratory information. In addition, bedside analytical systems are causing a quality assurance dilemma in which data can be seen and acted on before the appropriate quality checks are completed. Current information technology allows these data to be integrated and thus patient care processes to be enhanced through tracking of clinical outcomes and reducing costs. Because the goal of point-of-care testing is to provide data in a timely manner, the future success of any point-of-care/satellite testing system will depend on the ease with which it can be integrated into the medical information system.

Clinical Laboratory Information Systems↗
PubMed1995

Intraperitoneal micro-organisms and the severity of peritonitis.

OBJECTIVE: To find out if there was any correlation between the type or number of pathogenic bacteria in peritoneal exudate, the values of various prognostic scores, the inflammatory response, and the outcome, in patients with peritonitis. DESIGN: Prospective open study. SETTING: University hospital, Germany. SUBJECTS: 51 Consecutive patients with secondary peritonitis. INTERVENTIONS: Laparotomy within 12 hours of admission or within 8 hours of diagnosis in 9 patients with postoperative peritonitis. MAIN OUTCOME MEASURES: Correlation between the severity of the disease (APACHE II score, Septic Severity Score, Mannheim Peritonitis Index, Peritonitis Index Altona II, and outcome), the intraperitoneal and the systemic inflammatory response, intraperitoneal and systemic endotoxin concentrations, and type and number of micro-organisms grown from peritoneal fluid. RESULTS: Intra-abdominal microbiological findings did not correlate with severity of illness judged by the scoring systems, the later incidence of infective complications, or the final outcome. The presence of intra-abdominal microbes was associated with signs of a systemic inflammatory response (median activation index 3 (range 1-3) compared with 2 (range 1-3)), the length of history (median 52 hours (range 3-72) compared with 16 hours (range 3-56), and local and systemic concentrations of endotoxin (peritoneal exudate: median 4800 EU/ml (range 0.06-136674) compared with 220 EU/ml (range 0.00-1800); plasma: median 0.05 EU/ml (range 0.00-1.32) compared with 0.04 EU/ml (range 0.00-0.13)). The sensitivity of the organisms to the antibiotics given (cefuroxime and metronidazole) did not influence the incidence of later infective complications or the outcome. CONCLUSIONS: These results do not suggest micro-organisms invading the peritoneal cavity and respective antibiotic treatment to be major determinants of the clinical course of peritonitis.

APACHE↗
PubMed1995

Effects of peritonitis exudates on chemotaxis and phagocytosis of human neutrophils.

OBJECTIVE: To elucidate the in vitro effects of peritoneal exudate in patients with peritonitis on the functions of normal neutrophils (chemotaxis and phagocytosis) and to correlate these findings with constituents of the exudate, severity of disease, and clinical course. DESIGN: Open study. SETTING: University hospital, Germany. SUBJECTS: Fifty consecutive patients with secondary peritonitis and healthy volunteers. INTERVENTIONS: Samples of peritoneal exudate were taken during operation and tested for their ability to stimulate or inhibit chemotaxis and phagocytosis of polymorphonuclear neutrophils (PMN). MAIN OUTCOME MEASURES: Correlation between chemotaxis and phagocytosis and concentrations of constituents of peritoneal exudate. RESULTS: Mean (SD) exudate-induced chemotaxis was 102.5 (22.8) microns compared with 62.3 (4) in the buffer control and 116 (17) in the 1 ng/ml C5a buffer control. The mean (SD) phagocytic index (uptake of zymosan and Candida albicans) was 68.8 (28.1) % of the respective serum control. There were correlations between chemotaxis and concentrations of C3a, endotoxin, and white cell count in the exudates; between phagocytosis and concentrations of C3a, IgG, IgM, protein and granulocyte elastase activity (GE and GE-alpha 1 proteinase inhibitor complex) in the peritoneal exudate; concentrations of endotoxin, and tumour necrosis factor alpha (TNF alpha), and granulocyte elastase activity in the exudate; and concentrations of C3a, IgG, IgM, and fibrinopeptide A in the exudate. There were no differences in chemotaxis and phagocytosis between patients who survived and those who died, and only the APACHE II score, the Sepsis Severity Score and the Mannheim Peritonitis Index correlated with mortality. CONCLUSION: It is still not clear whether other constituents of the exudate, variable conditions of resorption, inflammatory conditions within the peritoneal lining, or the individual patient's capacity to limit the systemic response, may have a critical role.

APACHE↗
PubMed1994

Involvement of SRE element of Ty1 transposon in TEC1-dependent transcriptional activation.

Some Ty1 transposable element insertion mutations of Saccharomyces cerevisiae activate transcription of adjacent genes in a cell-type dependent manner. This activation requires at least STE12 and TEC1 gene products. The binding site for the STE12 protein is located in the sterile responsive element (SRE), which is just downstream the 5' LTR of Ty1 and contains one copy of the pheromone response element (PRE). This report defines the sequences in Ty1 required for TEC1-dependent activation using a TDH3::lacZ reporter gene in which the UAS was replaced by different portions of a Ty1 or Ty2 element. The Ty1 SRE seems to be sufficient to ensure the TEC1 and STE12-mediated activation whereas Ty2 SRE can activate the expression of the adjacent genes in the absence of both proteins. Adjacent to the PRE element, there is a region (PAE) with extensive sequence divergence in Ty1 and Ty2 SREs. Swapping experiments between Ty1 and Ty2 sequences show that Ty1 PAE is required for the activation of adjacent gene expression in a TEC1 and STE12-dependent manner. The use of a LexA::TEC1 construct indicates that the chimeric protein has no activation ability suggesting that TEC1 could act in conjunction with another factor.

Base Sequence↗
PubMed1994

Production of monoclonal antibodies recognising the peptide core of MUC2 intestinal mucin.

A peptide based on the tandem repeat sequence of MUC2 mucin was used to produce a series of monoclonal antibodies (MAb). The fine specificity of these antibodies and their implications for MUC2 expression are presented. Three of the MAbs, 996/1, 996/7 and 995/25, were specific to the MUC2p and failed to bind to peptides based on the MUC1,3,4 tandem repeat sequences whereas three others, 994/152, 994/91 and 996/36, cross reacted with the MUC2p and the MUC3 tandem repeat peptide but not the MUC1 and MUC4 peptides. An antigen, affinity purified from a colorectal tumour on one of the MUC2p-specific MAbs, 996/1, was shown to be a high molecular weight polydisperse, mucin-like antigen. Two of the MAbs, 996/1 and 994/152, recognised MUC2 in tissue sections, although the fine specificity varied between the two MAbs, with 994/152 strongly staining gastric, ileum and kidney epithelia, and MAb 996/1 intensely staining colon, liver and prostate tissues. These antibodies also stained a colorectal cell line, and MAb 994/152 also stained a gastric and an ovarian cell line. Six of the MAbs were used to stain colorectal tumour and adjacent 'normal' colonic mucosa sections. All six stained normal mucosa, but only two of the MAbs, 996/1 and 994/91, stained tumour tissue. The staining probably reflects exposure of cryptic epitopes due to varying levels of glycosylation in different tissues. These anti-MUC2p MAbs may help in determining the normal role of MUC2 mucin and how it is subverted in malignancy.

Amino Acid Sequence↗
PubMed1994

Isolation and characterization of Saccharomyces cerevisiae mRNA transport-defective (mtr) mutants.

To understand the mechanisms of mRNA transport in eukaryotes, we have isolated Saccharomyces cerevisiae temperature-sensitive (ts) mutants which accumulate poly(A)+ RNA in the nucleus at the restrictive temperature. A total of 21 recessive mutants were isolated and classified into 16 complementation groups. Backcrossed mRNA transport-defective strains from each complementation group have been analyzed. A strain which is ts for heat shock transcription factor was also analyzed since it also shows nuclear accumulation of poly(A)+ RNA at 37 degrees C. At 37 degrees C the mRNA of each mutant is characterized by atypically long polyA tails. Unlike ts pre-mRNA splicing mutants, these strains do not interrupt splicing of pre-mRNA at 37 degrees C; however four strains accumulate oversized RNA polymerase II transcripts. Some show inhibition of rRNA processing and a further subset of these strains is also characterized by inhibition of tRNA maturation. Several strains accumulate nuclear proteins in the cytoplasm when incubated at semipermissive temperature. Remarkably, many strains exhibit nucleolar fragmentation or enlargement at the restrictive temperature. Most strains show dramatic ultrastructural alterations of the nucleoplasm or nuclear membrane. Distinct mutants accumulate poly(A)+ RNA in characteristic patterns in the nucleus.

Biological Transport↗
PubMed1994

A comparative study of intravenous versus intralymphatic interleukin-2, with assessment of effects of interleukin-2 on both peripheral blood and thoracic-duct lymph.

Recombinant human interleukin-2 (IL-2) was administered by the intravenous (i.v.) or intralymphatic (i.l.) route to 14 patients with advanced malignancy. IL-2 was given in doses of 600,000 IU/kg or 1,050,000 IU/kg daily x 5. Thoracic duct (TD) catheters were placed, and both TD lymphocytes (TDL) and peripheral blood lymphocytes (PBL) were studied. Five of eight patients at the 600,000 IU/kg dose experienced grade III toxicity as did five of six patients at the 1,050,000 IU/kg dose. Two episodes of grade IV toxicity were seen at the higher dose. The i.l. and i.v. routes had a similar toxicity profile excepting lymphangitis/pedal infection, seen only with i.l. administration. One partial response was seen in a patient with renal cell carcinoma. Lymphopenia was seen early in therapy, with lymphocytosis by day 6. Lymphoid yield of the TD catheter fell early in therapy, then increased over baseline by the end of treatment. Intralymphatic administration resulted in a prolonged serum t1/2 and lower serum levels than did i.v. administration, but resulted in higher TD levels. Antibodies against IL-2 were ubiquitous but had no clear effects. Lymphocyte trafficking studies suggested that IL-2 affected lymphocyte redistribution to liver, spleen, bone marrow, and lymph nodes. NK activity and phenotype and LAK activity increased in response to IL-2, with no advantage for TDL. Tumor necrosis factor-alpha and gamma-interferon levels increased sporadically with treatment. The i.l. route offered no advantage over the i.v. route, and TDL offered no advantage over PBL.

Adult↗
PubMed1994

Cytokine gene expression in the lungs of BALB/c mice during primary and secondary intranasal infection with Mycoplasma pneumoniae.

Cytokine gene expression was determined in vivo in the lungs and spleens of Mycoplasma pneumoniae-infected BALB/c mice by means of qualitative and semiquantitative PCR-mediated mRNA amplification. During the acute phase of both primary and secondary infections, cytokines commonly associated with innate resistance, TNF alpha, IFN gamma, IL-1 beta and IL-6, were expressed. In contrast, early expression of the genes for IL-2 and IL-2 receptor was detected only during reinfection. Expression was greater in the lungs than in the spleen, attesting to the rapid accumulation of lymphocytes at the infected site. Interestingly, IL-2 mRNA expression declined rapidly and was no longer detectable after 24 h, whereas IL-10 mRNA levels rose sharply during the same period. During reinfection, mRNAs for TNF alpha and IL-6 were 10-fold and for IFN gamma about 50-fold higher than during primary challenge. The results suggest that the pathogenesis of M. pneumoniae diseases may be associated with elevated expression of proinflammatory cytokines.

Acute Disease↗
PubMed1994

Characterization of a highly structured domain in Tbp2 from Neisseria meningitidis involved in binding to human transferrin.

The binding of iron-loaded human transferrin at the surface of Neisseria meningitidis is mediated by two polypeptides, Tbp1 and Tbp2. Predicted Tbp amino acid sequences from N. meningitidis strains are highly divergent. This variability is particularly pronounced throughout the Tbp2 polypeptide. In this study, a highly structured and extremely stable Tbp2 domain of about 270 to 290 amino acids which is involved in the binding to transferrin and whose position is well conserved has been characterized. The conservation of such a remarkable structure in a very divergent protein domain (there is only 43% amino acid identity within this region) suggests that is plays an essential biological role and raises a number of questions regarding tbp2 evolution.

Amino Acid Sequence↗
PubMed1994

Continuous measurements of changes in pulmonary capillary surface area with 201Tl infusions.

The impact of physiological and pathological processes on metabolism and transport of a variety of substances traversing the pulmonary vasculature depends in part on the capillary surface area available for exchange, and a reliable method for detecting changes in this parameter is needed. In this study, a continuous-infusion approach was used to investigate the response of the pulmonary capillary surface area to increases in flow and left atrial pressure. Isolated rat lungs were perfused with an acellular perfusion solution containing 125I-labeled albumin (an intravascular indicator) and 201Tl, a K+ analogue which is concentrated within lung cells. The extraction of 201Tl from the perfusate was 61% greater at low flow (8.5 ml/min) than at high flow (26 ml/min), and rapid changes in extraction were observed when flow was altered. In contrast, the permeability-surface area product was 76% greater when lungs were perfused at high flow than at low flow, suggesting comparable increases in pulmonary capillary surface area in these zone 2 lungs (airway pressure = 5 cmH2O, left atrial pressure < 0 cmH2O). In a second group of experiments, increases in left atrial pressure to 14 cmH2O (zone 3 lungs) at a constant flow of 8.5 ml/min increased the permeability-surface area product by only 18% despite increases in average intravascular pressure that were at least as high as those associated with high perfusion rates. 201Tl infusions provide a useful method for detecting and quantifying changes in pulmonary capillary surface area.

Animals↗
PubMed1994

Flushing with autologous blood improves intraoperative hemodynamic stability and early graft function in clinical hepatic transplantation.

Hemodynamic instability and hyperkalemia are common after reperfusion and may cause ischemic damage on the hepatic allograft. Two techniques for flushing hepatic grafts before reperfusion were studied to evaluate their effects on intraoperative hemodynamic and metabolic status and on early graft function in 83 consecutive adult hepatic transplantations. In the first 41 patients (group 1), the hepatic grafts were rinsed with 500 milliliters of lactated Ringer's solution (LR). In the subsequent 42 patients (group 2), in addition to LR rinse, the first 500 milliliters of portal blood to flush and reperfuse the liver were drained through the cannula inserted into the donor vena cava before unclamping the vena cava. After reperfusion, the mean arterial pressure decreased 30 +/- 4 percent in group 1 versus 17 +/- 2 percent in group 2 (p < 0.02), and serum K+ increased by 1.9 +/- 0.2 in group 1 versus 0.8 +/- 0.2 milliequivalents per liter in group 2 (p < 0.01). Hyperkalemic cardiac arrest was only seen in two patients in group 1. The K+ concentration in the first 100 milliliters of discarded blood was found to be 40 +/- 2 milliequivalents per liter. The 500 milliliters of discarded blood contained 8.3 +/- 0.4 milliequivalents, which was correlated with graft liver weight (p < 0.001). Early graft function, as measured by serum glutamic-oxaloacetic transaminase, serum glutamic pyruvic transaminase, total bilirubin and prothrombin time on postoperative day No. 2, was significantly better in group 2 than in group 1 (p < 0.05). The six-month graft and patient survival rates in group 1 were 66 and 75 percent, versus 90 and 95 percent in group 2 (p < 0.01 and p < 0.02, respectively). Further flushing with 500 milliliters of autologous portal blood resulted in smaller intraoperative shifts in serum K+, greater hemodynamic stability, better graft function and improved graft and patient survival.

Adult↗
PubMed1993

Cloning and characterization of Neisseria meningitidis genes encoding the transferrin-binding proteins Tbp1 and Tbp2.

Genes tbp1 and tbp2, encoding the transferrin-binding proteins Tbp1 and Tbp2, have been isolated from two strains of Neisseria meningitidis. The tbp2 and tbp1 open reading frames are tandemly arranged in the genome with an 87-bp intergenic region, and the DNA region upstream from the tbp2-coding sequence contains domains homologous to Escherichia coli promoter consensus motives. Nucleotide sequence analysis suggests the existence of a Tbp1 precursor carrying an N-terminal signal peptide with a peptidase I cleavage site and of a Tbp2 precursor with N-terminal homology to lipoproteins, including a peptidase II cleavage site. Comparison of the Tbp1 deduced amino acid (aa) sequences from both strains showed about 76% aa homology, while those of Tbp2 revealed only about 47% aa homology. These comparisons should be extended to other Neisseria strains in order to evaluate further this genetic divergence further.

Amino Acid Sequence↗
PubMed1993

Characterization of the cellular response of spleen cells in BALB/c mice inoculated with Mycoplasma pneumoniae or the P1 protein.

BALB/c mice were intranasally infected or intraperitoneally inoculated with Mycoplasma pneumoniae whole cells or were immunized with the isolated adhesin (P1 protein). Spleen cells were isolated and tested in vitro for proliferation activity after stimulation with the P1 protein and sonicated M. pneumoniae whole antigen preparations. In frequency analysis experiments the P1 protein-specific proliferative response of spleen lymphocytes increased from 1/11494 in mice immunized once to 1/3246 in eightfold-inoculated mice, demonstrating that the P1 protein is a prominent immunogen of M. pneumoniae cells. Depletion experiments showed that T and B cells are activated in a 2:1 relation. Fluorescence-activated cells sorting analysis revealed a shift of the CD4/CD8 ratio from 2:1 in control mice up to 3:1 in M. pneumoniae-, and to 3.4:1 in P1 protein-immunized mice, as well as an increase in interleukin 2 receptor-bearing cells and macrophage cell populations. The results indicate that this animal model is appropriate to study host-M. pneumoniae interactions and vaccination schedules.

Adhesins, Bacterial↗
PubMed1993

Identification of Chlamydia pneumoniae-specific protein antigens in immunoblots.

The immunoblot patterns of 248 sera, all examined previously by the microimmunofluorescence test (MIF) for species-specific Chlamydia antibodies, were analyzed. Predominant specific antibody activity was directed to the 54 kDa protein of Chlamydia pneumoniae, which was recognized by 93% of sera positive for Chlamydia pneumoniae by MIF but by only 2% of sera positive for Chlamydia trachomatis and negative for Chlamydia pneumoniae and by 3% of sera negative for both Chlamydia pneumoniae and Chlamydia trachomatis. This antigen appears to be specific for Chlamydia pneumoniae. Other Chlamydia pneumoniae-specific protein antigens were recognized far less frequently. Absorption analysis indicated that the 54 kDa protein is located on the surface of the Chlamydia pneumoniae elementary bodies.

Antigens, Bacterial↗