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Biomedical subjects

S Schroeder

Publications and source records attributed to S Schroeder.

At least 55 records · Page 3Linked to original sources

Case of synovitis potentially caused by Dolosigranulum pigrum.

We report a case of synovitis in a 64-year-old man who developed the infection while on steroid therapy for rheumatoid arthritis. Dolosigranulum pigrum, a gram-positive catalase-negative coccus, was isolated from two sets of blood cultures prior to antibiotic therapy. The patient was treated with 4 weeks of appropriate antibiotics, and the synovial inflammation resolved. Although synovial aspirates were never positive for any bacteria or fungi, the timing of positive blood cultures and absence of other pathogens suggest the possible etiology as D. pigrum.

Blood↗

Weissella confusa (basonym: Lactobacillus confusus) bacteremia: a case report.

Infection with Lactobacillus is rare, and only a handful of species have been identified as being clinically significant: Lactobacillus casei, Lactobacillus rhamnosus, and Lactobacillus leichmannii. The literature contains one case report of bacteremia caused by Weissella confusa (basonym: Lactobacillus confusus), but the clinical significance of the infection was unclear. We describe a case of W. confusa bacteremia in a 46-year-old man with a history of abdominal aortic dissection and repair. This procedure was complicated by gut ischemia, which necessitated massive small bowel resection. He subsequently developed short-bowel syndrome, which required him to have total parenteral nutrition. He later developed an Enterococcus faecalis aortic valve endocarditis that required a coronary artery bypass graft and aortic root replacement with homograft and 6 weeks of intravenous ampicillin and gentamicin. Three months prior to his most recent admission, he was diagnosed with Klebsiella pneumoniae bacteremia and candidemia. At the present admission, he had fever (T(max), 39.5 degrees C) and chills of 2 days' duration and was admitted to the intensive care unit because of hemodynamic instability. Blood cultures grew K. pneumoniae and W. confusa in four of four blood culture bottles (both aerobe and anaerobe bottles). Imaging studies failed to find any foci of infection. A transesophageal echocardiogram revealed no vegetations. A culture of the patient's Hickman catheter tip was negative. The patient was treated with piperacillin-tazobactam and gentamicin. His condition improved, and he was discharged home, where he completed 4 weeks of piperacillin-tazobactam therapy. Lactobacillemia seldom results in mortality; however, it may be a marker of a serious underlying disease. It is usually seen in patients who have a complex medical history or in patients who receive multiple antibiotics. Lactobacillus spp. are generally associated with polymicrobial infections, and when isolated from the blood, they need to be considered possible pathogens. The presence of a vancomycin-resistant, gram-positive coccobacilli on a blood culture should alert clinicians to the possibility of bacteremia caused by W. confusa or other small gram-positive rods.

Bacteremia↗

Coronary arteries: retrospectively ECG-gated multi-detector row CT angiography with selective optimization of the image reconstruction window.

PURPOSE: To investigate how the technique of retrospective gating can be used to optimize reconstruction of multi-detector row computed tomographic (CT) images for each of the three major coronary arteries during the cardiac cycle. MATERIALS AND METHODS: Multi-detector row coronary CT angiograms obtained in 50 patients were reconstructed at 20%-80% of the cardiac cycle in increments of 10%. Two blinded independent reviewers assessed the image quality, in terms of artifacts and visibility, obtained with three-dimensional postprocessing for segments 1-3 (right coronary artery), segments 5-8 (left main and left anterior descending coronary arteries), and segments 11 and 12 (left circumflex artery). The following grades were assigned: 1, very poor; 2, poor; 3, fair; 4, good; and 5, excellent. RESULTS: The left anterior descending artery was best visualized in middiastole at 60%-70% of the cardiac cycle, and the left circumflex artery was best visualized at 50%. The optimal reconstruction window for the right coronary artery was significantly different at 40% (P < .05). Although there was good agreement (kappa = 0.75) between the two reviewers, there was a high degree of variation in the patient population. CONCLUSION: The image reconstruction window for CT angiography of the coronary arteries should be adapted to each coronary artery. The use of one fixed time point in the cardiac cycle for image reconstruction does not provide optimal image quality.

Aged↗

Decreased immunogenicity of recombinant hepatitis B vaccine in chronic hepatitis C.

The immunogenicity of hepatitis B vaccine is unknown for patients with chronic hepatitis C, although hepatitis B vaccination is highly recommended in these patients. We therefore studied in a prospective open trial of 59 patients with chronic hepatitis C (mean age 42 years, hepatitis C for >10 years, Child-Pugh score < or = 5) and 58 healthy hospital staff persons the rate of nonresponse (anti-HBs <10 mIU/mL at 9 months) to recombinant hepatitis B vaccine (Gen H-B-Vax(R),10 microg intradeltoidal at month 0, 1, and 6). Nonresponse was observed in 18/59 (31%) patients with chronic hepatitis C and 5/58 (9%) healthy staff persons (P <.005) (vs. 7% in historical controls; P <.005), low response (anti-HBs 10-99 mIU/mL) in 19% of patients with chronic hepatitis C and 17% of staff persons. High-dose booster vaccination led to seroconversion in 12/15 (80%) of primary nonresponders. Primary nonresponse to HB vaccine was related neither to presence of early-stage liver cirrhosis nor magnitude of serum hepatitis C virus (HCV) RNA concentration, nor explained by the presence of human leukocyte antigen (HLA) types (B8 DR3, B44, DR7, DQ2) predisposing to low antibody response to hepatitis B surface antigen. The rate of primary nonresponse to the standard regimen of recombinant hepatitis B vaccine is surprisingly high in patients with longstanding chronic hepatitis C. Therefore, the antibody to HBV surface antigen (anti-HBs) titer response should be determined in these patients. Depending on the response titer, higher booster doses may be required to achieve and maintain seroprotection in these patients.

Adult↗

The Pstl polymorphism of the endotoxin-inducible heat-shock protein 70-2 gene does not affect messenger RNA level in human whole-blood cultures.

OBJECTIVE: To determine whether the human leukocyte antigen linked biallelic heat-shock protein 70-2 (HSP70-2) gene polymorphism is associated with variable HSP70-2 messenger RNA expression. DESIGN: Prospective observational study in consecutive healthy blood donors. SETTING: Department of Anesthesiology, laboratory for molecular biology in a university hospital. PARTICIPANTS: 24 healthy blood donors. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: We studied the functional implication of the HSP70-2 (G/A) PstI gene polymorphism in 24 healthy, white blood donors with various HSP70-2 (G/A) genotypes by analyzing the endotoxin-inducible HSP70-2 mRNA expression by means of the reverse transcription-polymerase chain reaction. HSP70 expression was expressed semiquantitatively by calculating the ratio of HSP70-2 mRNA and the constitutively expressed glutaraldehyde 3-phosphate dehydrogenase mRNA. No significant differences in HSP70-2 mRNA expression after lipopolysaccharide (from Salmonella minnesota Re 595) stimulation were detected in individuals homozygous for the allele A (0.68, range 0.38-1, n = 10), in individuals homozygous for the allele G (0.79, range 0.42-1.1, n = 8), and in heterozygotes (HSP70-2 G/A; 0.52, range 0.4-0.67, n = 6; p > 0.05). CONCLUSIONS: The PstI polymorphism of the endotoxin-inducible HSP70-2 gene is not associated with variable HSP70-2 mRNA expression ex vivo. This finding is in accordance with the observation that HSP70-2 genotypes do not affect clinical outcome in human systemic inflammation.

Adult↗

Agrobacterium-mediated sorghum transformation.

Agrobacterium tumefaciens was used to genetically transform sorghum. Immature embryos of a public (P898012) and a commercial line (PHI391) of sorghum were used as the target explants. The Agrobacterium strain used was LBA4404 carrying a 'Super-binary' vector with a bar gene as a selectable marker for herbicide resistance in the plant cells. A series of parameter tests was used to establish a baseline for conditions to be used in stable transformation experiments. A number of different transformation conditions were tested and a total of 131 stably transformed events were produced from 6175 embryos in these two sorghum lines. Statistical analysis showed that the source of the embryos had a very significant impact on transformation efficiency, with field-grown embryos producing a higher transformation frequency than greenhouse-grown embryos. Southern blot analysis of DNA from leaf tissues of T0 plants confirmed the integration of the T-DNA into the sorghum genome. Mendelian segregation in the T1 generation was confirmed by herbicide resistance screening. This is the first report of successful use of Agrobacterium for production of stably transformed sorghum plants. The Agrobacterium method we used yields a higher frequency of stable transformation that other methods reported previously.

Agrobacterium tumefaciens↗

The impact of untreated coronary dissections on acute and long-term outcome after intravascular ultrasound guided PTCA.

AIM: Vessel size adapted PTCA results in the use of larger balloons with an increased incidence of severe vascular dissections. The aim of our trial was (a) to evaluate the effect of severe dissections on the acute outcome and (b) to study the natural history of dissections after 1 year. METHODS AND RESULTS: One hundred and seventy-eight patients with 195 lesions underwent vessel size adapted PTCA using intravascular ultrasound. Clinical and angiographic 1 year follow-up was obtained for all patients. Intravascular ultrasound was performed before PTCA to measure the external elastic membrane diameter at the lesion site so that the balloon size could be adopted (external elastic membrane-10%) and post-interventionally to determine the procedural success and the incidence of intracoronary dissections. Stent implantation was reduced to persistently flow limiting dissections (TIMI I, II). Dissections were detected by intravascular ultrasound in 128/195 (66%) lesions (by angiography in 111/195 [58%] lesions) and classified by intravascular ultrasound criteria into four groups: group I: no dissection (67 lesions [34%]), group II: mild dissections (21 lesions [11%]), group III: medium dissections (19 lesions [10%]) and group IV: severe dissections (88 lesions [45%]). Because of threatened vessel closure, GPIIb/IIIa antagonists were used in eight (4.5%) patients and a stent was implanted in two (1. 1%) patients. The cumulative event rate after 1 year was 12% and the global angiographic restenosis rate was 19%. The post-interventional evidence of severe dissections was associated with a decrease in clinical events during long-term follow up (group I: 13 events [19%] vs group IV: seven events [7%];P=0.03). This was also true for the occurrence of restenosis which was significantly lower in patients with severe dissections (group I: 19 [28%] lesions vs group IV:10 [11%] lesions;P=0.01). CONCLUSIONS: According to the theory of 'therapeutic dissections', our data suggest that substantial dissections following PTCA, which do not diminish antegrade blood flow, do not lead to an increase in acute or long-term events. The natural history of vessel injury seems to provide favourable wound healing without increase of restenosis. Thus, stenting for treatment of large dissections without flow limitation does not seem to be mandatory.

Acute Disease↗

Reduction of restenosis by vessel size adapted percutaneous transluminal coronary angioplasty using intravascular ultrasound.

Restenosis following percutaneous transluminal coronary angioplasty (PTCA) remains a serious problem in interventional cardiology. Recent trials using stent implantation have proposed a reduction in restenosis, presumably due to a higher initial luminal gain. This study was conducted to evaluate if the short- and long-term results following conventional PTCA may be favorable, if balloon dilation was performed according to measurements gained by intravascular ultrasound (IVUS) (vessel size adapted PTCA). The use of intracoronary stents might be omitted if comparable long-term results could be achieved by this modified technique of balloon angioplasty. This unicenter and nonrandomized pilot trial was initiated in January 1995 with 252 patients who had 271 lesions. IVUS was performed before and after intervention to determine the external elastic membrane (EEM) diameter at the lesion site. The balloon catheter was sized according to the EEM diameter measured by IVUS (EEM 10%). The mean balloon diameter was 4.1 +/- 0.5 mm, the dilation time 130 +/- 60 seconds with a balloon pressure of 7.0 +/- 2.0 atm. Clinical acute and 1-year long-term follow-up were obtained for all patients and follow-up angiography in 71% of patients. Acute events occurred postinterventionally in 5 patients (2%). The cumulative event rate during long-term follow-up was 14%. The angiographic restenosis rate (diameter stenosis >50%) after 1 year was 19%. Vessel size adapted PTCA using IVUS led to favorable acute and long-term results with a low restenosis rate and a low 1-year clinical event rate. Despite dissections that occur frequently using large balloon sizes, an increased rate of major complications did not occur, indicating a safe procedure and substantiating the philosophy of "therapeutic dissections." The results need to be verified in a randomized trial.

Angioplasty, Balloon, Coronary↗

T lymphocyte costimulation mediated by reorganization of membrane microdomains.

Although dispensable, costimulation through CD28 facilitates activation of naïve T lymphocytes. CD28 engagement led to the redistribution and clustering of membrane and intracellular kinase-rich raft microdomains at the site of T cell receptor (TCR) engagements. Although not affecting TCR down-regulation, this process led to higher and more stable tyrosine phosphorylation of several substrates and higher consumption of Lck. These results may provide a general mechanism for amplifying receptor signaling by reorganization of membrane microdomains.

Antigen-Presenting Cells↗

Endotoxin inhibits heat shock protein 70 (HSP70) expression in peripheral blood mononuclear cells of patients with severe sepsis.

OBJECTIVE: To investigate the ex vivo endotoxin-inducible heat shock protein 70 (HSP70) expression in the peripheral blood mononuclear cells (PBMC) of patients with severe sepsis in order to assess the capacity of this potentially protective response during systemic inflammation. DESIGN: Prospective observational study in consecutive patients with severe sepsis and healthy blood donors. SETTING: Surgical intensive care unit in a university hospital. PATIENTS AND PARTICIPANTS: Eleven patients with the diagnosis of severe sepsis, one patient who had recovered from severe sepsis and 13 healthy blood donors. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: We studied the inducibility of HSP70 expression in the PBMC of patients with severe sepsis and healthy blood donors ex vivo. Human whole blood was incubated with variable lipopolysaccharide (LPS from Salmonella minnesota Re 595) concentrations (0; 0.1; 10; 100 ng/ml) for different periods of time (0.5; 2; 4; 10 h). The PBMC were separated by Ficoll density gradient and then disrupted by hypotonic lysis. HSP70 was measured by means of enzyme-linked immunosorbent assay (ELISA). We found a LPS dose- and time-dependent inhibition of ex vivo HSP70 expression in the PBMC of both patients with severe sepsis and healthy individuals. However, the levels of HSP70 expression in patients were significantly lower compared to those of healthy individuals at all LPS concentrations and incubation times. On average, HSP70 expression in the PBMC of healthy controls was 2.8 (range 1.2-3.9) times higher than in patients. HSP70 expression was inducible by thermal heat shock in the PBMC of both patients and healthy individuals. CONCLUSIONS: Endotoxin inhibits HSP70 expression in PBMC ex vivo. In vivo, the suppression of HSP70 expression induced by endotoxin and high levels of proinflammatory cytokines may contribute to the cellular dysfunction of immunocompetent cells concerning antigen presentation, phagocytosis and antibody production associated with decreased resistance to infectious insults during severe sepsis.

Adult↗

Noninvasive determination of endothelium-mediated vasodilation as a screening test for coronary artery disease: pilot study to assess the predictive value in comparison with angina pectoris, exercise electrocardiography, and myocardial perfusion imaging.

BACKGROUND: Peripheral endothelial dysfunction (ED) quantified by the determination of flow-mediated dilation (FMD%) of the brachial artery with the use of high-resolution ultrasound is an early marker of atherosclerosis. Although a positive correlation with coronary artery disease (CAD) has been reported, the unanswered clinical question is the validity of FMD% as a screening test in patients with clinical suspicion of CAD. Thus the aim of this study was to determine the predictive value of FMD% compared with angina pectoris, exercise electrocardiography, and myocardial perfusion imaging. METHODS AND RESULTS: In this pilot study, we measured ED in 122 patients scheduled for coronary angiography by using high-resolution ultrasound (13 MHz). We defined ED as FMD% </=4.5%. The presence of CAD was defined as angiographically detectable atherosclerotic vessel alterations of any degree. Exercise electrocardiography and myocardial perfusion imaging had been performed on an outpatient basis. Statistical analysis was conducted by analysis of variance and Mantel-Haenszel chi-square test. Patients with CAD (n = 101) had a significantly lower FMD% than patients without CAD (n = 21; 3.7% +/- 4.1% vs 7.01% +/- 3.5%, P <.001). A sensitivity of 71%, a specificity of 81% with a positive predictive value of 0.95 (72 of 76), and a negative predictive value of 0.41 (17 of 46) was calculated. In comparison to angina pectoris (sensitivity 95%, specificity 47.6%), exercise electrocardiography (sensitivity 82.4%, specificity 57.1%) and myocardial perfusion imaging (sensitivity in our study group 100%) had the best specificity, and a high sensitivity for FMD% was found. CONCLUSIONS: The determination of ED was found to be a sensitive and specific screening test to predict the presence of CAD. Because this is a noninvasive, nonradioactive, and cost-effective approach, it warrants further evaluation to determine its value in daily clinical practice as an additional screening test in the diagnosis of CAD.

Angina Pectoris↗

Impaired inducibility of heat shock protein 70 in peripheral blood lymphocytes of patients with severe sepsis.

OBJECTIVE: To determine the extent of the potentially protective heat shock protein 70 response in peripheral blood lymphocytes of patients with severe sepsis after ex vivo lipopolysaccharide stimulation. DESIGN: Entry study of consecutive patients with severe sepsis, those who were critically ill or nonseptic after major surgery, and healthy blood donors. SETTING: Surgical intensive care unit in a university hospital. PATIENTS: Ten patients with diagnoses of severe sepsis; ten critically ill, nonseptic patients after major surgery; and ten healthy blood donors. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We investigated the ex vivo endotoxin-inducible expression of heat shock protein 70 in peripheral blood lymphocytes of patients with severe sepsis by means of flow cytometry. Only negligible amounts of inducible intracellular heat shock protein 70 accumulation (<4.2% of lymphocytes) could be detected in peripheral blood lymphocytes without lipopolysaccharide stimulation. The proportion of cells accumulating heat shock protein 70 after treatment with lipopolysaccharide was distinctly lower in patients with severe sepsis (p < .05) than in critically ill, nonseptic patients after major surgery and healthy blood donors (38.3+/-3.3%, 82.2+/-4.5%, and 70.9+/-3.9%, respectively; mean +/- SEM; n = 10). Patients with clinical signs of recovery from severe sepsis showed an increase in heat shock protein 70 expression. CONCLUSIONS: Inducibility of ex vivo heat shock protein 70 was impaired in peripheral blood lymphocytes of patients with severe sepsis. The impaired expression of the potentially protective heat shock protein 70 may contribute in vivo to immune dysfunction, because intact functioning of T and B lymphocyte responses is of central importance in resisting infection in severe sepsis. Monitoring of inducible heat shock protein 70 in peripheral blood lymphocytes may contribute to the evaluation of the immune consequences of severe sepsis.

APACHE↗

Analysis of two human leukocyte antigen-linked polymorphic heat shock protein 70 genes in patients with severe sepsis.

OBJECTIVE: To determine whether the genotype and allelic frequencies of two human leukocyte antigen-linked bi-allelic 70-kilodalton heat shock protein (HSP70) gene polymorphisms are associated with susceptibility to and outcome of severe sepsis. Furthermore, we investigated a possible linkage between HSP70 gene polymorphisms and the previously reported and mortality-related tumor necrosis factor-beta (TNF-beta) NcoI gene polymorphism. DESIGN: Consecutive entry study of patients with severe sepsis. SETTING: Surgical intensive care unit in a university hospital. PATIENTS: Eighty-seven patients with a diagnosis of severe sepsis. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We studied two bi-allelic polymorphisms within the coding region of the constitutively expressed HSP70-HOM C/T, and the stress-inducible HSP70-2 G/A in patients with severe sepsis. The HSP70-HOM Ncol, HSP70-2 Pstl, and TNF-beta NcoI polymorphisms were identified by means of the polymerase chain reaction followed by restriction analysis of the polymerase chain reaction product. No significant differences in genotype and allelic frequencies were observed for both HSP70 gene polymorphisms between the 87 patients and the 110 healthy Caucasians serving as the control group. In addition, no differences in genotype and allelic frequencies between surviving and nonsurviving patients were detected. The allelic frequencies in the group of nonsurvivors were 0.8 for the HSP70-HOM C allele and 0.2 for the HSP70-HOM T allele vs. 0.87 and 0.13 for the survivors (p > .05). The frequency for the HSP70-2 G allele was 0.36 and 0.64 for the HSP70-2 A allele in the group of nonsurvivors vs. 0.41 and 0.59 for the survivors (p > .05). Analysis of a possible linkage between HSP70 and TNF-beta genotypes resulted in a significant association (odds ratio, 4.15; p < .01) of the HSP70-2 A/A homozygous genotype and the TNFB2/B2 homozygous genotype, which is reported to be a genomic marker for a poor prognosis in severe sepsis. CONCLUSIONS: Our data show that the bi-allelic NcoI and PstI polymorphisms within the HSP70-HOM and HSP70-2 locus, respectively, are associated with neither susceptibility to nor outcome of severe sepsis. Moreover, we found a linkage between HSP70-2 A homozygotes and the previously reported and mortality-related homozygous genotype, TNFB2/B2, in patients suffering from severe sepsis.

Case-Control Studies↗