Point-of-care testing in the cardiovascular operating theatre

Point-of-care testing (POCT) remains under scrutiny by healthcare professionals because of its ill-tried, young history. POCT methods are being developed by a few major equipment companies based on rapid progress in informatics and nanotechnology. Issues as POCT quality control, comparability with standard laboratory procedures, standardisation, traceability and round robin testing are being left to hospitals. As a result, the clinical and operational benefits of POCT were first evident for patients on the operating table. For the management of cardiovascular surgery patients, POCT technology is an indispensable aid. Improvement of the technology has meant that clinical laboratory pathologists now recognise the need for POCT beyond their high-throughput areas. Clin Chem Lab Med 2006;44:1060-

Granulocyte Neutral Proteases and Pseudomonas Elastase as Possible Causes of Airway Damage in Patients with Cystic Fibrosis

We studied the possible role of granulocyte neutral proteases as mediators of airway destruction in patients with cystic fibrosis (CF) who were infected with Pseudomonas aeruginosa. We measured the enzymatic activities of bronchial secretions on purified radioactively labeled complement component three (C3), elastin, and a granulocyte elastase-specific substrate. Bronchial secretions from 18 patients with CF who were infected with P aeruginosa had a significantly higher mean value for C3 cleaving, elastolytic, and granulocyte elastase-like activity than did two control groups. High enzymatic activities were observed in patients with CF who have advanced bronchial disease (that had been determined by a clinical scoring system). Kinetics of proteolysis of radioactively labeled C3 and inhibition profiles of the activities of the three enzymatic activities studied suggest that they are mainly derived from granulocytes. In addition, 20 of 31 strains of P aeruginosa isolated from patients with CF inactivated purified α1-antiprotease in vitro. We postulate that granulocyte neutral proteases and P aeruginosa may act synergistically in the airways of patients with CF and may contribute to the destruction of elastin and inactivation of C

Pathogenesis of Foreign Body Infection: Description and Characteristics of an Animal Model

An animal model involving the subcutaneous implantation of tissue cages into guinea pigs and subsequent infection with Staphylococcus aureus was used to study factors pertinent to foreign body infection. Whereas 108 colony-forming units (cfu) of S. aureus strain Wood 46 did not produce any abscesses in the absence of foreign material, 102 cfu was sufficient to infect 95% of the tissue cages despite the presence of polymorphonuclear leukocytes (PMNLs) in sterile tissue cage fluid. Opsonization of S. aureus by tissue cage fluid was adequate during the first hour of infection, but opsonic coating of the organisms decreased at 20 hr after the induction of infection. PMNLs from sterile tissue cage fluid showed decreased phagocytic and bactericidal activities when compared with PMNLs from either blood or peritoneal exudate obtained after short- or long-term stimulation (P < 0.001

Complement-Mediated Opsonic Activity in Normal and Infected Human Cerebrospinal Fluid: Early Response During Bacterial Meningitis

A local defense mechanism in bacterial meningitis was evaluated in humans by measuring complement-mediated opsonic activity (CMOA) in normal and infected cerebrospinal fluid (CSF) with a complement-dependent phagocytic bactericidal assay. CMOA was absent in normal untreated CSF and remained undetectable in 20 samples of CSF from patients with viral meningitis and five samples from patients with acute meningococcemia. In contrast, 15 of 27 samples of CSF from patients with acute bacterial meningitis had a measurable CMOA, which was correlated with protein concentrations (P < 0.01) and C4 hemolytic activity (P < 0.001) in the CSF. A favorable outcome of bacterial meningitis was associated with the presence of CMOA in CSF (P < 0.005). Recovery was also correlated with higher levels of C4 (P < 0.01) and C3 (P < 0.05) in CSF and with lower concentrations of microorganisms in the sample of CSF collected at the time of admission (P < 0.01). Thus, CMOA, although absent in normal CSF, can appear in CSF during acute bacterial meningitis, particularly in patients who recover completel

Glycaemic patterns in healthy elderly individuals and in those with impaired glucose metabolism - exploring the relationship with nonglycaemic variables.

OBJECTIVE The SENIORLABOR study data were explored (i) to examine the evolution during senescence of the differences between measured glycated haemoglobin (HbA1c) values and the values predicted by using regression to extrapolate from measured fructosamine levels; (ii) to scrutinise the relationship between the glycation gap and insulin resistance using a homeostasis model assessment, and between the glycation gap and a low-grade inflammation marker (C-reactive protein serum concentration); and (iii) to investigate the glycation gap ranges in relation to triglyceride levels and kidney function. SUBJECTS AND METHODS A total of 1432 Swiss individuals aged &gt;60 years and classified as healthy (547), prediabetic (701) or diabetic (184) based on their fasting plasma glucose and HbA1c values were included in the study. The glycation gap was evaluated and assigned to one of four categories: &lt;&minus;0.5; &minus;0.5 to &lt;0.0; 0.0 to &le;0.5; &gt;0.5. RESULTS In healthy and prediabetic participants, the homeostasis model assessment for estimation of insulin resistance (p &lt;0.01), high-sensitivity C-reactive protein (p &lt;0.001) and triglyceride (p = 0.02) values tended to increase with increasing glycation gap category and were highest in the glycation gap category &gt;0.5. Homeostasis model assessment for estimation of insulin resistance, high-sensitivity C-reactive protein and triglyceride levels tended to increase with increasing glycation gap category and were highest in the glycation gap category &gt;0.5. Significant differences (p &lt;0.01) between glycation gap categories were seen among different high-sensitivity C-reactive protein concentration groups. Interestingly, in diabetic participants, homeostasis model assessment for estimation of insulin resistance values, triglyceride concentrations and estimation of glomerular filtration values all decreased with decreasing glycation gap category. In the group of participants with a glycation gap &gt;0.5, high-sensitivity C-reactive protein values tended to increase with increasing glycation gap, whereas for participants with type 2 diabetes and in the glycation gap group &gt;0.5, high-sensitivity C-reactive protein levels tended to decrease as the glycation gap increased. The percentage of participants with type 2 diabetes mellitus increased from 2% in the glycation gap category &lt;&minus;0.5 to 76% in the glycation gap category &gt;0.5. In contrast, the percentage of healthy participants fell from 85% to 7%. CONCLUSION This is the first time that a direct comparison of healthy, prediabetic and diabetic participants, all assessed under identical conditions and using identical methodology, has clearly demonstrated a different glycation gap pattern. Thus, we contribute evidence that the glycation gap might be of interest in the care of diabetic patients and their prophylaxis, while acknowledging that more studies are needed to confirm our findings. (Trial registration number ISRCTN53778569)

Host Factors Selectively Increase Staphylococcal Adherence on Inserted Catheters: A Role for Fibronectin and Fibrinogen or Fibrin

Intravascular catheters are prone to staphylococcal infections. To study the role in staphylococcal adherence played by fibrinogen or fibrin and fibronectin deposited on inserted catheters, 187 peripheral or central cannulae were prospectively removed from hospitalized patients. Compared with uninserted catheters, which allowed only minimal adherence, previously inserted catheters promoted significant adherence of staphylococcal isolates from patients with intravenous device infections. Adhesion-promoting properties were studied with laboratory strains having well-defined affinities for either fibronectin or fibrinogen adherence of Staphylococcus aureus Cowan I, which has the highest affinity for both adhesins, was more strongly promoted (10- to 50-fold) on inserted cannulae than was that of S. aureus Wood 46 (4- to lO-fold) or Staphylococcus epidermidis Rp 12 (2.2-fold), which has no affinity for fibrinogen but does for fibronectin. Although all types of cannulae contained significant amounts of fibrin, which may promote adherence of coagulase-positive staphylococci, results obtained with coagulase-negative isolates suggested that in vivo-deposited fibronectin is also a critical determinant in this proces

Reference Intervals for Platelet Counts in the Elderly: Results from the Prospective SENIORLAB Study.

Currently, age- and sex-independent reference limits (RLs) are frequently used to interpret platelet counts in seniors. We aimed to define and validate reference intervals (RIs) for platelet counts within the framework of the prospective SENIORLAB study. Subjectively healthy Swiss individuals aged 60 years and older were prospectively included and followed for morbidity and mortality. Participants who had circumstances known to affect platelet counts were excluded. The obtained RIs were validated with indirect statistical methods. Frequencies of abnormal platelet counts in a population-based setting, including 41.5% of the entire age-specific population of the Principality of Liechtenstein, were compared by using age- and sex-independent RIs and the RLs obtained in the present study. For males (n = 542), 95% RIs for platelet counts were defined as follows: 150-300 × 109/L (60-69 years); 130-300 × 109/L (70-79 years); and 120-300 × 109/L (80 years and above). For females (n = 661), the consolidated age-independent 95% RI was 165-355 × 109/L. These RI values were validated by indirect RI determination of 51,687 (30,392 female/21,295 male) patients of the same age. Age- and sex-independent RIs exhibited imbalanced frequencies of abnormal platelet counts between the two sexes, which were corrected by introducing age- and sex-specific RLs. In conclusion, females have higher platelet counts than males. Whereas the upper RL for males remains constant, the lower RL decreases with age. We propose to abandon the practice of employing sex- and age-independent RL for platelet counts in the elderly

Geoepidemiology of autoimmune hemolytic anemia.

Autoantibodies against red blood cell antigens are considered the diagnostic hallmark of AIHA: Direct antiglobulin test (DAT) completed by cytofluorometry and specific diagnostic monoclonal antibodies (mAbs) allow for a better understanding of autoimmune hemolytic anemia (AIHA) triggers. Once B-cell tolerance checkpoints are bypassed, the patient loses self-tolerance, if the AIHA is not also caused by an possible variety of secondary pathogenic events such as viral, neoplastic and underlying autoimmune entities, such as SLE or post-transplantation drawbacks; treatment of underlying diseases in secondary AIHA guides ways to curative AIHA treatment. The acute phase of AIHA, often lethal in former times, if readily diagnosed, must be treated using plasma exchange, extracorporeal immunoadsorption and/or RBC transfusion with donor RBCs devoid of the auto-antibody target antigen. Genotyping blood groups (www.bloodgen.com) and narrowing down the blood type subspecificities with diagnostic mAbs help to define the triggering autoantigen and to select well compatible donor RBC concentrates, which thus escape recognition by the autoantibodies

Point-of-care testing in the cardiovascular operating theatre

Point-of-care testing (POCT) remains under scrutiny by healthcare professionals because of its ill-tried, young history. POCT methods are being developed by a few major equipment companies based on rapid progress in informatics and nanotechnology. Issues as POCT quality control, comparability with standard laboratory procedures, standardisation, traceability and round robin testing are being left to hospitals. As a result, the clinical and operational benefits of POCT were first evident for patients on the operating table. For the management of cardiovascular surgery patients, POCT technology is an indispensable aid. Improvement of the technology has meant that clinical laboratory pathologists now recognise the need for POCT beyond their high-throughput areas