Combined effect of acute altitude exposure and vigorous exercise on platelet activation.

Exposure to high altitudes and exercise alters body's physiology and may cause acute cardiovascular events. Platelet activation is one of the key players in these events. Therefore, we investigated the effect of vigorous exercise at higher altitude (2650 m) on platelet aggregation and serum markers of platelet activation. 14 healthy subjects performed a step incremental ergometer test until exhaustion at the Environmental Research Station (UFS, 2650 m) at Zugspitze. Platelet aggregation and serum levels of endothelin-1, soluble p-selectin, platelet factor 4 and Chromogranin A were measured. Platelet activation was significantly enhanced after exercise at high altitude compared to measures immediately prior exercise. We detected significantly enhanced serum levels of endothelin-1 and soluble p-selectin whereas chromogranin A and platelet factor 4 remained unchanged. This effect might be due to increased endothelin-1 levels causing pulmonary vasoconstriction, rheological changes and direct platelet activation. This might be of clinical relevance, especially in patients with pre-existing diseases.

Soluble Vascular Cell Adhesion Molecule-1 (VCAM-1) as a Biomarker in the Mouse Model of Experimental Autoimmune Myocarditis (EAM).

Vascular cell adhesion molecule-1 (VCAM-1) is strongly upregulated in hearts of mice with coxsackie virus-induced as well as in patients with viral infection-triggered dilated cardiomyopathy. Nevertheless, the role of its soluble form as a biomarker in inflammatory heart diseases remains unclear. Therefore, we investigated whether plasma levels of soluble VCAM-1 (sVCAM-1) directly correlated with disease activity and progression of cardiac dysfunction in the mouse model of experimental autoimmune myocarditis (EAM). EAM was induced by immunization of BALB/c mice with heart-specific myosin-alpha heavy chain peptide together with complete Freund`s adjuvant. ELISA revealed strong expression of cardiac VCAM-1 (cVCAM-1) throughout the course of EAM in immunized mice compared to control animals. Furthermore, sVCAM-1 was elevated in the plasma of immunized compared to control mice at acute and chronic stages of the disease. sVCAM-1 did not correlate with the degree of acute cardiac inflammation analyzed by histology or cardiac cytokine expression investigated by ELISA. Nevertheless, heart to body weight ratio correlated significantly with sVCAM-1 at chronic stages of EAM. Cardiac systolic dysfunction studied with positron emission tomography indicated a weak relationship with sVCAM-1 at the chronic stage of the disease. Our data provide evidence that plasma levels of sVCAM-1 are elevated throughout all stages of the disease but showed no strong correlation with the severity of EAM.

Retrospective analysis of circulatory support with the Impella CP® device in patients with therapy refractory cardiogenic shock.

BACKGROUND: In cardiogenic shock (CS) the Impella CP® device provides a fast available left ventricular circulatory support of up to 4.0L/min. However, the use of the Impella CP® device was not systematically analysed yet. METHODS: We performed a retrospective analysis of 28 consecutive patients suffering from severe therapy refractory CS treated with Impella CP®. Mortality was estimated using the SAPS II-Score. Primary outcome was 30-day survival. We compared the different aetiologies of CS and the effect of additional extracorporeal life support (ECLS). RESULTS: Aetiology of CS was acute coronary syndrome (ACS) in 15 patients, 9 patients received additional therapy with ECLS. SAPS II was 73±14, representing an estimated mortality of 87.1%. 18 patients deceased representing a 30-day survival of 36%. Comparing the different aetiologies, ACS-CS patients show a trend towards better survival. Additional therapy with ECLS did not change 30-day survival. In 3 cases, vascular complication needing surgical treatment occurred. All other patients showed no relevant complications except for the commonly seen haemolysis with consecutive need of transfusion. CONCLUSION: Our data could demonstrate that the Impella CP® application in these severely diseased patients is feasible and safe. Compared to the estimated mortality, the 30-day survival seems to be improved.

Multicenter evaluation of four methods for Clostridium difficile detection: ImmunoCard C. difficile, cytotoxin assay, culture, and latex agglutination.

A three-center study was undertaken to compare several test methods for the detection of Clostridium difficile, associated toxin, or related markers by using 927 stool specimens. Methods included direct assay of cytotoxin in stool by tissue culture, C. difficile bacterial culture followed by cytotoxin assay, bacterial culture alone, latex agglutination assay, and the ImmunoCard C. difficile test (Meridian Diagnostics, Inc.). The sensitivities, as determined against direct cytotoxin assay results, of the ImmunoCard C. difficile and latex agglutination assays were 84 and 67%, respectively (92 and 77%, respectively, when adjusted for bacterial culture outcomes). Evaluation for C. difficile-associated disease (CDAD) among 864 patients was based on clinical criteria for antibiotic-associated diarrhea combined with laboratory evidence of toxin or toxin-producing C. difficile in stool specimens. The sensitivity of each test method for screening of CDAD was as follows: bacterial culture, 95%; culture with cytotoxin assay of isolates, 90%; ImmunoCard C. difficile test, 83%; cytotoxin assay 82%; and latex agglutination assay, 67% (P < or = 0.05 versus all other methods). The standard deviations of the test sensitivity statistics between study sites were ranked as follows: cytotoxin assay (+/- 3.1%) < ImmunoCard C. difficile test (+/- 5.7%) < latex agglutination assay (+/- 12.3%) < culture (+/- 24.7%) < culture with cytotoxin assay (+/- 28.0%). The data support the use of the ImmunoCard C. difficile test as an adjunct for the diagnosis of CDAD.

Collaborative evaluation of the Radiometer Sensititre AP80 for identification of gram-negative bacilli.

A multicenter trial of the Sensititre AP80 panel read on the Sensititre AutoReader (Radiometer America, Westlake, Ohio) for the automated identification of gram-negative bacilli was conducted with 1,023 clinical isolates (879 members of the family Enterobacteriaceae plus 144 nonenteric organisms). Assignment of taxa was based on the computer-assisted interpretation of the results of a series of reactions with fluorogenic enzyme substrates after 5 h of incubation, with an incubation interval of approximately 18 h used when indicated. Accuracy was determined initially by comparison with the results obtained with the API 20E or Rapid NFT system (Analytab Products, Plainview, N.Y.). Isolates showing discrepancies were identified by using conventional biochemical profiles. Identifications were available after 5 h of incubation for 918 isolates (90%). Agreements with reference results for members of the family Enterobacteriaceae were 95.3 and 92.5% at the genus and species levels, respectively, and for the nonmembers of the family Enterobacteriaceae, the agreements with reference results were 95.1 and 84.7%, respectively. The Sensititre AP80 panel was found to be simple and convenient to use, allowed for the testing of three isolates per panel, required minimal supplementary testing for completion of identification, performed in a reproducible fashion, and demonstrated an accuracy of same-day identification comparable to that reported for other automated systems. The AP80 panel appears well suited for routine use in the clinical microbiology laboratory as an automated means of identifying both members of the family Enterobacteriaceae and nonenteric gram-negative bacilli.

Colonization by enteroaggregative Escherichia coli in travelers with and without diarrhea.

Enteroaggregative Escherichia coli (EAggEC) has been found to be associated with pediatric diarrhea in developing countries. In order to determine the role of EAggEC as an agent of traveler's diarrhea, we used a sensitive and specific DNA probe for EAggEC to screen bacterial colony blots from 278 volunteers before and after travel. Colonization with EAggEC was infrequent (2.5%) prior to travel but rose to 27 to 33% after travel in volunteers who took either placebo or trimethoprim-sulfamethoxazole. Travelers who took trimethoprimsulfamethoxazole were colonized with organisms that were uniformly resistant to that antimicrobial agent; when volunteers received ciprofloxacin, colonization with EAggEC was prevented (2.0%). Although colonization rates were high in the placebo and trimethoprim-sulfamethoxazole groups, only a minority of travelers who were colonized with EAggEC experienced diarrhea. On the basis of our data, we suggest that colonization with EAggEC alone is not sufficient to cause traveler's diarrhea.

Survival of Streptococcus pneumoniae in corneal storage media.

The Cincinnati Eye Bank had six corneoscleral rims in which Streptococcus pneumoniae was cultured after preservation in corneal storage media. To determine the survival of this organism under conditions common for corneal storage, gentamicin-supplemented McCarey-Kaufman (M-K) medium and chondroitin sulfate/Dextran medium (Dexsol, Ciron Ophthalmics, Irvine, CA, U.S.A.) were inoculated with S. pneumoniae and kept at 4 degrees C. Thioglycollate broth plus 10% rabbit serum (Thio-S) and tryptic soy broth (TSB) served as growth controls. At day 14 after inoculation of 10(5) colony-forming units (CFU)/ml, Dexsol showed a 1-log decrease in bacterial concentration, the M-K medium a 2-log decrease and Thio-S a 4-log decrease, whereas TSB showed no detectable organisms. By day 21 Dexsol had only a 2-log decrease in bacteria. These data suggest that corneal storage medium supplemented with gentamicin does not exert bactericidal activity against S. pneumoniae and may actually support its survival at 4 degrees C.

Management of radiation-induced moist skin desquamation using hydrocolloid dressing.

Moist skin desquamation has been of concern to radiation oncologists, nurses and patients since the inception of this mode of therapy. As radiation treatment machines became more sophisticated, severe reactions became less of a problem. However, with the increasing use of chemotherapy and radiation as combined modalities, moist skin reaction is occurring with greater frequency. A noncomparative study of 20 patients using a hydrocolloid occlusive dressing (Duoderm) was initiated. The purpose of the study was to determine whether moist occlusive healing would be beneficial. The dressing was evaluated on the basis of healing time, safety, wound temperature, bacterial growth, and comfort. Data were collected using photographs, bacterial cultures, temperature probes, and patient evaluations. Eighteen patients completed the study. All patients' skin reactions healed. There were no wound infections evident. Mean healing time was 12 days, with mean wound temperature relative to body core -0.8 degree C on day 1 and -1.2 degrees C on the healed site. Patient results on comfort were: 8 of 18 excellent, 7 of 18 good, 3 of 18 fair, and 0 of 18 poor. The results of this study indicate that a hydrocolloid occlusive dressing can be effective in the healing process of moist skin reaction that is due to radiation therapy.

Bioassay of teicoplanin in serum containing rifampin or a beta-lactam antibiotic.

The purpose of this study was to develop bioassays for the measurement of teicoplanin in serum containing rifampin or a beta-lactam antibiotic. Use of rifampin-resistant Bacillus subtilis as indicator organism or pretreatment of the serum sample with Bacillus cereus penicillinase Type I (nafcillin, ticarcillin, mezlocillin) or Type II (cefazolin, cefuroxime, ceftazidime, ceftriaxone) effectively eliminated assay interference. Validation bioassays performed on two separate days utilizing triplicate coded serum samples containing 0 to 200 micrograms teicoplanin in combination with 40 micrograms/ml rifampin or 200 to 500 micrograms/ml beta-lactam showed no significant differences (p greater than 0.05, two-way analysis of variance) in analyte recovery between assay days. Regression analysis of each teicoplanin/rifampin or teicoplanin/beta-lactam data set yielded slope values of 0.92 to 1.01, intercept values of -0.45 to 0.84 and correlation coefficients of 0.9925 to 0.9990. Thus, serum teicoplanin can be quantitated accurately, precisely, and reproducibly in patients receiving concomitant rifampin or beta-lactam chemotherapy.

Distribution and expression of toxic shock syndrome toxin 1 gene among Staphylococcus aureus isolates of toxic shock syndrome and non-toxic shock syndrome origin.

Toxic shock syndrome toxin 1 (TSST-1), plays a significant role in the pathogenesis of TSS. TSST-1 production is subject to physiologic and environmental constraints. Thus, DNA probes that detect the chromosomal gene encoding the toxin are of value diagnostically, epidemiologically, and for studies of gene expression. Several synthetic oligonucleotide probes complementary to two regions of the TSST-1 gene were used to ascertain the presence of this gene in the chromosomal DNA of 261 strains of S. aureus from various TSS-related and non-TSS-related sources. Isolates were from clinically confirmed menstrual and nonmenstrual cases of TSS and from healthy vaginal carriers of S. aureus. Other strains tested included clinical non-TSS isolates and food poisoning-associated staphylococcal isolates. Detection of the TSST-1 gene by the labeled gene probes correlated in all but two cases with production of TSST-1. Ten Centers for Disease Control (CDC) strains that were isolated from TSS patients and did not produce TSST-1 were also examined, as were several strains of Staphylococcus epidermidis isolated from patients with suspected TSS. Neither group of strains possessed the TSST-1 gene. Finally, a 7-kilobase DNA restriction fragment of S. aureus containing the entire TSST-1 gene was transformed into Escherichia coli strains HB101 and DH5 alpha via a plasmid vector.

Performance characteristics of a commercially prepared biphasic blood culture bottle.

A biphasic blood culture bottle (BiPB: GIBCO Laboratories, North Andover, Mass.) with an architectural design that physically separates the agar slant from the broth was compared with a conventional vented monophasic bottle (MPB-A) for use in the routine culture of blood. Both bottles contained tryptic soy broth. Tryptic soy agar was used for the BiPB slant. A third unvented bottle (MPB-N) with Columbia broth was included as part of the blood culture set. Of 3,537 sets collected, 444 were positive; 57 of these 444 sets were positive by virtue of an exclusively positive anaerobic bottle. Both BiPB and MPB-A were positive in 235 of the remaining 387 positive sets. A total of 521 isolates was recovered during the study. Of these isolates, 252 were recovered in both the BiPB and the MPB-A from the same set; 105 isolates grew in the BIPB but not in MPB-A, 95 isolates grew only in the MPB-A but not in BiPB, and 69 grew exclusively in the MPB-N. The BiPB allowed more rapid recovery of Candida spp., J-K diphtheroids, Pseudomonas spp. Making BiPB subcultures was easy enough to permit both early and daily subculture, which provided isolated colonies sooner than could be done by using the MPB-A. Isolated colonies and, therefore, identification and susceptibility results were available at least 1 day earlier for the BiPB isolates in approximately 50% of instances when both the BiPB and the MPB-A were positive. Staphylococcus epidermidis and streptococci were recovered more frequently in the BiPB, while gram-positive anaerobes were detected at a significantly (P less than 0.025) more frequent rate in the MPB-A than in the BiPB. Either bottle, however, should be used in conjunction with an anaerobic bottle for optimal recovery of anaerobic bacteria.

Antibody responses to toxic-shock-syndrome (TSS) toxin by patients with TSS and by healthy staphylococcal carriers.

Serum samples taken from women with toxic-shock syndrome (TSS) and from women without a history of TSS were examined for the presence of antibodies to toxic-shock-syndrome toxin (TST). Serum samples from 38 women with TSS and from 70 women with no history of TSS were analyzed by radioimmunoassay (RIA) and by an enzyme-linked immunoadsorbent assay (ELISA). Antitoxin titers obtained by the assays were highly correlated. Antibody levels in sera of women with TSS, or a history of TSS, were significantly lower than levels in sera of women with no prior evidence of TSS. The mean level of antitoxin titers in the total sample of acute, convalescent, and recovered TSS groups was significantly lower than that of the control groups, which consisted of 31 carriers of genital Staphylococcus aureus and a similar number of age- and race-matched noncarriers. Although a trend toward elevated antitoxin titers was apparent after recovery, no vigorous immunologic response to TST was noted. In contrast, the majority of healthy women demonstrated measurable antitoxin titers, a finding indicative of current or prior colonization with TST-producing strains of S. aureus. The data suggest that absence of antibodies to the TSS toxin may be a predisposing factor in the development of clinical disease.

Rapid screening assay for toxic shock syndrome toxin production by Staphylococcus aureus.

A rapid immunoblot assay (TST-blot) was developed and used to screen Staphylococcus aureus isolates for toxic shock syndrome toxin (TST) production. Growth from an 18-h stab inoculum of S. aureus on brain heart infusion agar was transferred directly to a nitrocellulose sheet. Nonspecific protein binding sites were blocked with bovine serum albumin, and the nitrocellulose sheet was incubated with affinity-purified antibody to TST, followed by incubation with horseradish peroxidase-conjugated protein A. Toxin was visualized by detection of the peroxidase-conjugated protein A-anti TST-TST complex with 4-chloro-1-napthol. The sensitivities and specificities of the TST-blot and Ouchterlony microslide immunodiffusion assay were compared by screening 141 S. aureus isolates for TST production. In both assays, 53 of 141 isolates produced detectable levels of TST, whereas 88 isolates produced no toxin. A 100% concordance was found between the two assays. The TST-blot yielded the same results in less than 24 h as those yielded by the 3-day immunodiffusion assay. Thus, this rapid method for detection of TST in multiple samples appears to be well suited for diagnostic and epidemiological studies. Furthermore, it would appear to be ideal for use in TST genetics research.

Production of staphylococcal enterotoxin F and pyrogenic exotoxin C by Staphylococcus aureus isolates from toxic shock syndrome-associated sources.

A total of 136 isolates of Staphylococcus aureus were tested for production of staphylococcal enterotoxin F (SEF) and pyrogenic exotoxin C (PEC), both of which have been identified as reliable indicators of toxic shock syndrome (TSS)-associated strains. SEF and PEC production by isolates from TSS-associated and other sources was tested independently in two laboratories, after which the two sets of data were compared. A 100% concordance between SEF and PEC production was obtained. The TSS toxin candidates were produced by 30 of 136 isolates, and in all instances SEF and PEC were made concurrently by the same strains; in no case was one toxin made and not the other. In the five groups of S. aureus tested, toxins were detected as follows: 23 of 25 (92%) acute TSS isolates, 2 of 48 (4.2%) genital non-TSS isolates, 2 of 16 (12.5%) recovered TSS isolates, 1 of 23 (4.3%) clinical nongenital isolates, and 2 of 24 (8.3%) enterotoxigenic food outbreak isolates. Comparison of purified SEF and purified PEC by immunological and biochemical criteria by immunodiffusion, isoelectric focusing, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and Western blot analysis show that the toxins are immunologically identical and strongly suggest that the two nominal TSS toxins are in fact a single protein.

Aflatoxin production by Aspergillus parasiticus in a competitive environment.

Aspergillus parasiticus NRRL 2999 was grown in the presence of Rhizopus nigricans, Saccharomyces cerevisiae, Acetobacter aceti, or Brevibacterium linens and aflatoxin concentration was determined after 3,5,7, and 10 days of incubation at 28C. R. nigricans and S. cerevisiae inhibited growth and aflatoxin production by A. parasiticus. B. linens caused slight inhibition and A. aceti stimulated growth and aflatoxin production by A. parasiticus.