The Rivalta's test as a diagnostic variable in feline effusions--evaluation of optimum reaction and storage conditions.

OBJECTIVE: The Rivalta's test is used to diagnose feline infectious peritonitis (FIP) in cats with effusion. Only little information on the influence of sample storage and reaction conditions on test results is available, and diagnostic sensitivity and specificity to diagnose FIP vary considerably between few available studies. This study determined the influence of storage of effusion, modifications on reaction conditions, and inter-observer variation. MATERIAL AND METHODS: The Rivalta's test was repeated up to 21 days after storage at room temperature, in the refrigerator, or freezer. The test was performed by two independent, blinded investigators. It was also performed using different volumes of acetic acid, different acids, and different kinds of water. RESULTS: Even after storage for 21 days, test results were comparable. While inter-observer variation revealed substantial disagreement, different modifications in performance showed no major influence on test outcome. CONCLUSION: The Rivalta's test seems to be a very robust test concerning storage conditions. Modifications in reaction condition also do not substantially influence outcome. However, the test is subjective and depends on the evaluating person.

Randomized, placebo controlled study of the effect of propentofylline on survival time and quality of life of cats with feline infectious peritonitis.

BACKGROUND: Currently there is no drug proven to effectively treat cats with feline infectious peritonitis (FIP). HYPOTHESIS: Propentofylline (PPF) can decrease vasculitis, and therefore prolong survival time in cats with FIP, and increase their quality of life. ANIMALS: Twenty-three privately owned cats with FIP. METHODS: Placebo-controlled double-blind trial. FIP was confirmed by histology or immunostaining of feline coronavirus (FCoV) antigen in effusion or tissue macrophages or both. The cats were randomly selected for treatment with either PPF or placebo. All cats received additional treatment with glucocorticoids, antibiotics, and low molecular weight heparin according to methods. RESULTS: There was no statistically significant difference in the survival time of cats treated with PPF (8 days, 95% CI 5.4-10.6) versus placebo (7.5 days, 95% CI 4.4-9.6). The median survival time of all cats was 8 days (4-36 days). There was neither a difference in quality of life (day 7, P = .892), in the amount of effusion (day 7, P = .710), the tumor necrosis factor-alpha (TNF-α) concentration (day 7, P = .355), nor in any other variable investigated in this study, including a complete blood count, and a small animal biochemistry profile. CONCLUSIONS AND CLINICAL IMPORTANCE: This study did not detect an effect of PPF on the survival time, the quality of life, or any clinical or laboratory parameter in cats with FIP. Therefore, PPF does not appear to be an effective treatment option in cats with a late stage of the disease FIP.

[Quality of life in children with obstructive sleeping disorder after tonsillectomy, tonsillotomy or adenotomy]. / Lebensqualität bei kindlichem obstruktiven Schlafapnoesyndrom nach Tonsillektomie, Tonsillotomie und/oder Adenotomie.

BACKGROUND: To study the effectiveness of adenotomy (AT), adenotonsillectomy (ATE) and adenotonsillotomy (ATT) with respect to the quality of life improvement in children with obstructive sleep disorders (OSD), OSA 18 survey and Brouillette score were used. METHODS: Prospectively, 92 children with an age ranging from 2 to 6 years with OSD underwent AT, ATE or ATT at the University hospital of Ulm (Germany), respectively. 30 age-matched children served as controls. Caregivers were requested to complete the Brouillette score and the OSA 18 survey, which are validated instruments for detecting symptoms and quality of life change in children with OSDs, at the initial office visit prior to surgery (BS/1 and OSA 18/1) and 7 - 14 months after surgery (BS/2 and OSA 18/2). RESULTS: The mean total score of the OSA 18 survey for AT, ATE and ATT was reduced significantly after these operations (p < 0.001). Similar results were also observed in the Brouillette score (p < 0.002). The improvement of life quality in the AT group was less effective than in the ATE and ATT group. CONCLUSION: ATE and ATT have about the same effectiveness to improve life quality for children with OSD. Children after ATE or ATT have a comparable life quality as healthy children (Mann Whitney U-test; p approximately 0.15), while children who only received AT have a slightly lower life quality after the operation. In summary, ATT was recommend.

[Efficacy and longterm compliance of the vest preventing the supine position in patients with obstructive sleep apnea]. / Effektivität und Langzeit-Compliance der Therapie mit Rückenlage-Verhinderungsweste bei obstruktiver Schlafapnoe.

BACKGROUND: Treating the positional obstructive sleep apnea with a vest preventing the supine position is well known to be riskless and inexpensive. It was the aim of this study to test the efficacy and, for the first time, the longterm compliance of this treatment. METHODS: 14 patients with positional obstructive sleep apnea (age 48.2 +/- 12.1 years; body-mass-index: 28.1 +/- 4.6 kg/m2 mean, +/- SD) were investigated polysomnographically without and with a vest preventing the supine position. 13.7 +/- 15.9 months later the patients were asked about the comfort of the vest and the nocturnal using time using the Likert-scale, and data about the latest Epworth Sleepiness Scale (ESS) was collected. RESULTS: The respiratory disturbance index (RDI) was reduced statistically significant from 31.3 +/- 12.9/h to 13.8 +/- 9.0/h by wearing the vest (p < 0.001). Total sleep time at an oxygen saturation below 90% decreased from 8.2 +/- 7.1% to 3.8 +/- 4.5% (p < 0.001), the snoring time from 15.4 +/-19.6 % to 9.8 +/-13.1% (p < 0.05) of the total sleep time (TST) and the arousal index from 23.1 +/-16.0/h to 18.6 +/-11.4/h (p < 0.05). 24 +/-28.8 months later 28.6% of the patients were still using the vest. Of these patients the ESS decreased from 8.5 +/-3.2 to 6.5 +/-2.9 (p < 0.05). 72.4% of the patients refused the longterm therapy with the vest because of its low wearing comfort. CONCLUSIONS: Although the vest approved to be effective against positional obstructive sleep apnea, the longterm compliance is low because of its need getting used to.

The adenosine A1 receptor antagonist SLV320 reduces myocardial fibrosis in rats with 5/6 nephrectomy without affecting blood pressure.

BACKGROUND AND PURPOSE: Myocardial fibrosis is an unwanted effect associated with chronic renal failure. The adenosine system is involved in cardiac and renal function. Therefore, we investigated the novel selective adenosine A(1) receptor antagonist SLV320 focusing on its potential in preventing cardiomyopathy in rats with 5/6 nephrectomy. EXPERIMENTAL APPROACH: Male Sprague-Dawley rats were allocated to 4 groups of 12 rats each: 5/6 nephrectomy (5/6 NX), 5/6 NX plus SLV320 (10 mg kg(-1) d(-1) mixed with food), sham and sham plus SLV320. Study duration was 12 weeks, blood pressure was assessed repeatedly. At study end kidney function was assessed, blood samples and hearts were taken for histology/immunohistochemistry. Pharmacological properties of SLV320 were assessed using receptor binding and enzyme assays and in vivo. KEY RESULTS: SLV320 is a selective and potent adenosine A(1) antagonist in vitro (Ki=1 nM) with a selectivity factor of at least 200 versus other adenosine receptor subtypes. Functional A(1) antagonism was demonstrated in vivo. In rats with 5/6 NX SLV320 significantly decreased albuminuria by about 50%, but did not alter glomerular filtration rate (GFR). SLV320 normalized cardiac collagen I+III contents in 5/6 NX rats. SLV320 prevented nephrectomy-dependent rise in plasma levels of creatinine kinase (CK), ALT and AST. Blood pressure did not differ between study groups. CONCLUSION: SLV320 suppresses cardiac fibrosis and attenuates albuminuria without affecting blood pressure in rats with 5/6 nephrectomy, indicating that selective A(1) receptor antagonists may be beneficial in uraemic cardiomyopathy.

[Examiner variability of clinical findings in patients with sleep related breathing disorders]. / Variabilität klinischer Befunde bei Patienten mit schlafbezogenen Atmungsstörungen in Abhängigkeit vom Untersucher.

BACKGROUND: Clinical findings in sleep related breathing disorders (SRBD) and primary snoring are not only of diagnostic but also of therapeutic relevance because clinical findings may be used for the selection of surgical interventions such as uvulopalatopharyngoplasty (UPPP), maxillofacial surgery or radiofrequency induced surgical alternatives. We developed a standardized protocol for clinical examination of the upper airway using pictograms. MATERIAL AND METHODS: To determine the interinvestigators variability various parameters such as length of the uvula, position of tongue base, Angle-classification, webbing of posterior pillar and tonsil size were assessed by a number of residents and an assistant professor for Otorhinolaryngology and sleep medicine simultaneously. RESULTS: 95 patients (81 male and 14 female) with a mean age of 47.0 +/- 1.21 years, a Body-Mass-Index (BMI) of 27.2 +/- 0.46 kg/m2, and an Apnea-Hypopnea-Index (AHI) of 17.7 +/- 2.4 were examined. The appearance of the uvula has only little variations between different investigators (corr.: 0.943). The interinvestigator variability is also low for position of tongue base (corr.: 0.931) and Angle-classification (corr.: 0.893). The results of tonsil size and webbing assessment seems to have a higher variability (corr.: 0.880 and 0.693). Statistical significance for all parameters was p=<0.0001. CONCLUSION: As to our knowledge, this is the first controlled study to record intraobserver variations of clinical findings of the upper airway. Standardized protocols are mandatory, and the variability of the measurements must be taken into account if results of different investigations must be compared or if changes after therapeutic interventions are to be investigated.

[Long term change in quality of life after adenotonsillectomy for pediatric obstructive sleep disorders]. / Anderung der Lebensqualität nach Adenotonsillektomie bei Kindern mit obstruktiven schlafbezogenen Atmungsstörungen.

BACKGROUND: To study short-term and long-term changes in quality of life (QOL) in children before and after adenotonsillectomy (T and A) for obstructive sleep disorders (OSDs). MATERIALS AND METHODS: Prospective study of 20 children underwent T and A for OSDs at the University hospital of Ulm/Germany. Caregivers were asked to complete the Brouillette-Score (BS) and OSA-18 survey, validated instruments for detecting symptoms and QOL change in children with OSDs, at the initial office visit prior to surgery (BS/1 and OSA-18/1) within 7.5 +/- 1.14 weeks after surgery (BS/2 and OSA-18/2), and 14.8 +/- 1.98 months after surgery (BS/3 and OSA-18/3). The BS comprises 3 items including: difficulty breathing during sleep, apnea observed by the caregivers and snoring. The OSA-18 survey comprises 18 items in 5 domains of sleep disturbance, physical suffering, emotional distress, daytime problems, and caregiver concerns. Scores from the preoperative and postoperative surveys were compared using the paired T-test and SPEARMAN-RANK test. RESULTS: 13 children were male (65 %). The mean age at the time of inclusion in the study was 6.2 +/- 1.63 years, mean preoperative body mass index (BMI) was 17.4 +/- 1.24 kg/m(2). Brouillette-Score: The mean Brouillette-Score before T and A (2.72) was significantly higher ( P = or < .001) than in the short-term (- 2.19) and in the long-term. (- 3.54). OSA-18 SURVEY: The mean total score for OSA-18/1 (83.4) was significantly higher ( P = or < .001) than the mean total score for OSA-18/2 (29.8) and OSA-18/3 (25.6). The overall correlation between BS and OSA-18 was R = .887 ( P = or < .001). CONCLUSION: Children with suspicious OSDs demonstrate significant short term and long-term improvement in the Brouillette-Score and OSA-18 survey. Caregivers perceive a long-term improvement for a minimum of one year in QOL after T and A for OSDs, although these improvements are not uniform across all domains of the OSA-18 survey. Use of the Brouillette-Score and the OSA-18 survey should decrease the need for polysomnographic monitoring and facilitate selection of children for T and A, whereas the OSA-18 questionnaire permits the more differentiated finding.

An autologous system for culturing head and neck squamous cell carcinomas for the assessment of cellular therapies on the chorioallantois membrane.

The evaluation of novel immunotherapeutic anti-cancer strategies requires target and effector cells from the autologous host to avoid false positive results because of allo-reactivity. Head and neck squamous cell carcinoma cells (HNSCC) do not proliferate under standard culture conditions in plastic ware. To create an autologous model, the chorioallantois membrane (CAM) of chicken embryos was employed to culture HNSCC and peripheral blood mononuclear cells (PBMC). Separated tumor cells were co-incubated with a cytostatic agent, PBMC, or mere cell culture medium as a control. Tumor cell lysis was assessed by acridine orange staining or by flow cytometry analysis of iodide marked cells after 24 and 48 h of co-incubation. Incubation with cisplatin resulted in a decrease of viable cells by 49% after 24 h and 48 h. In contrast, incubation with mere culture medium resulted in an increase of viable tumor cells by 5% after 24 h and a decrease of 4% after 48 h; the incubation of tumor cells and PBMC led to a non-significant decrease by 14% after 24 h and 16% after 48 h. Taken together, the CAM supports a favorable environment for the co-culture of HNSCC and PBMC, thus providing an approximated in vivo autologous model to assess the efficacy of new cell-therapeutical approaches.

[Sleep-related breathing disorders. Sleep anamnesis questionnaire and determination of clinical results within the framework of staged diagnostics]. / Schlafbezogene Atmungsstörungen. Schlafanamnesebögen und klinische Befunderhebung im Rahmen der Stufendiagnostik.

Sleep-related breathing disorders (SBAS) affect approximately 8% of the population of middle aged adults. At the age of 20 years, approximately 10% of the population snore, while at the age of 60 about 50% of men snore. Some 9% of middle aged women and 24% of middle aged men have an apnea hypopnea index (AHI) of >5 (number of nocturnal apnea and hypopnea per hour of sleep). Sleep apnea hypopnea syndrome is found in 2% of the women and 4% of the men, i.e. they have an AHI>5 associated with daytime sleepiness. Forms, check lists, summaries and patient-readable questionnaires have proved helpful in the evaluation of SBAS.

The use of an ambulatory, automatic sleep recording device (QUISI version 1.0) in the evaluation of primary snoring and obstructive sleep apnoea.

Electroencephalogram (EEG) evaluation with polysomnography (PSG) according to the Rechtschaffen & Kales (R&K) rules is time and cost consumptive, but ambulatory polygraphy systems do not allow EEG recording routinely. As a consequence, the number of sleep disordered events cannot be calculated exactly. QUISI is a one-channel, self-applicable ambulatory EEG recording device. The present study was designed as a prospective, non-randomized clinical trial. This investigation evaluated the results of 40 patients with primary snoring and obstructive sleep apnoea measured with level 1 PSG and QUISI simultaneously. Fifteen patients (37.5%) were primary snorers with normal sleep profiles, whereas 25 patients (62.5%) suffered from obstructive sleep apnoea (OSA) with a Respiratory Disturbance Index (RDI) of 38.6 +/- 23.8. The mean total sleeping time (TST) was underestimated by 4.5%, while Sleep Efficiency Index (SEI) was understimated by 4.6% by the QUISI device compared with PSG. The correlation between the QUISI and the PSG estimates for single sleep stages demonstrated only moderate correlation. The statistical significance for sleep stage 2 was r = 0.42, P = 0.002; for sleep stage 3/4, r = 0.31, P = 0.02; and for WAKE, r = 0.33, P = 0.01. Sleep stage 2 as well as sleep stage 3/4 were underestimated by QUISI substantially (difference: -5.6% and -10.3%), while WAKE was overestimated by QUISI to a larger amount (difference: +10.4%). Sensitivity and specificity of QUISI to recognize pathological sleep profiles compared with PSG/R&K were 0.92 and 0.96 respectively. QUISI is able to evaluate normal versus altered sleep profiles in patients with primary snoring and OSA. Comparing the quartile ranges, we found substantial differences between QUISI and PSG/R&K. QUISI gives an impression of sleep architecture and objective verification of a sleep disturbance in an ambulant setting but cannot replace the sleep laboratory-based PSG.

[Prevalence of obstructive sleep apnea syndrome (OSA) in patients with sudden hearing loss. A pilot study]. / Zur Prävalenz der obstruktiven Schlafapnoe (OSA) bei Patienten mit Hörsturz. Eine Pilotstudie.

BACKGROUND: It is estimated that in patients with sleep-related breathing disorders the probability of a cerebral vascular infarction (CVI) is 3.1 times that in patients without sleep apnea and that 25-50% of all patients who have a stroke suffer from sleep apnea (OSA) and have a respiratory disturbance index (RDI) higher than 10. CVI may be caused by variations in intracranial pressure or in intracranial hemodynamics owing to decreasing pO(2) and increasing pCO(2) during cessation of airflow. It is suspected that the most common causes of sudden deafness are vasospasm, thrombosis, embolism, hypercoagulation and sludging. The present study analyzed the prevalence of sleep apnea in patients with sudden hearing loss. PATIENTS AND METHODS: A 7-channel polygraph was used to test 33 subjects with normal hearing and 27 patients suffering from sudden hearing loss. Statistical analyses were performed with a Chi-square test and the Mann-Whitney test. RESULTS: We found that 29.6% of the patient group and 21.2% of those in the study control group were suffering from OSA and had RDI >10; this difference was not significant ( p=0.554). Sudden hearing loss may also be an indicator of arteriosclerosis secondary to such risk factors as hypertension ( p=0.005), diabetes ( p=0.003), and hyperlipidemia ( p=0.004), which were highly significant for the patient group. CONCLUSION: Patients who develop sudden hearing loss tend to have OSA more frequently than those in the control group owing to the similar risk factors for cerebral infarction and sudden hearing loss.

The endosomal compartment is an insulin-sensitive recruitment site for GLUT4 and GLUT1 glucose transporters in cardiac myocytes.

In nonstimulated cardiomyocytes, the glucose transporter GLUT4 is confined to intracellular vesicles forming at least two populations: a storage pool enriched in GLUT4 (pool 1) and an endosomal pool containing both GLUT4 and GLUT1 (pool 2). We have now studied the dynamics of these pools in response to insulin or the mitochondrial inhibitor rotenone in rat cardiomyocytes. Rotenone recruited GLUT4 and GLUT1 to the cell surface from endosomal pool 2 without affecting pool 1. Kinetic experiments were consistent with rotenone acting on an intracellular compartment that is in close connection with the plasma membrane. In contrast, insulin caused rapid, complete depletion of GLUT4 from pool 1 and reduced the GLUT1 content of pool 2 by approximately 50%, whereas, surprisingly, no net decrease in GLUT4 occurred in this pool. Subsequent insulin withdrawal resulted in slow replenishment of pool 2 with GLUT1 and of pool 1 with GLUT4. When pool 1 was still largely depleted of GLUT4, a second insulin challenge did reduce GLUT4 in pool 2 and stimulated glucose transport to the same extent as the first insulin treatment. In conclusion, the storage pool is the primary source of GLUT4 in response to insulin, but not to rotenone. In addition, the endosomal compartment is an important recruitment site of both GLUT1 and GLUT4 when the storage pool is either unaffected (rotenone) or depleted (by a previous insulin challenge). GLUT4 mobilized by insulin from the storage pool may pass through an intermediary (possibly endosomal) compartment on its way to the cell surface.

Inhibition of glucose transport by cyclic GMP in cardiomyocytes.

Recent evidence points to a potential role of cyclic GMP (cGMP) in the control of cardiac glucose utilization. The present work examines whether the glucose transport system of cardiac myocyte is a site of this cGMP-dependent regulation. Treatment of isolated rat cardiomyocytes (for 10 min) with the membrane-permeant cGMP analogue 8-(4-chlorophenylthio)-cGMP (8-p-CPT-cGMP, 200 microM) caused a decrease in glucose transport in non-stimulated (basal) myocytes, as well as in cells stimulated with insulin or with the mitochondrial inhibitor oligomycin B by up to 40%. An inhibitory effect was also observed with another cGMP analogue (8-bromo-cGMP), and in cells stimulated by hydrogen peroxide or anoxia. In contrast, 8-p-CPT-cAMP (200 microM), or the beta-adrenergic agonist isoprenaline (which increases cAMP levels) did not depress glucose transport, and even potentiated the effect of insulin. Blockade of endogenous cGMP formation with the guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, 10 microM) significantly increased basal and insulin-dependent glucose transport (by 25%), whereas addition of the guanylate cyclase activator 3-(5'-hydroxymethyl-2'furyl)-1-benzylindazol (YC-1, 30 microM) produced a depression of glucose transport (by 20%). Confocal laser scanning microscopic studies revealed that cGMP partially prevents the insulin-induced redistribution of the glucose transporter GLUT4 from intracellular stores to the cell surface. These observations suggest that the glucose transport system of cardiomyocytes represents a metabolic target of inhibition by cGMP, and that this regulation occurs at the level of the trafficking of glucose transporters.

Heart-type fatty acid binding protein (hFABP) in the diagnosis of myocardial damage in coronary artery bypass grafting.

OBJECTIVES: Heart-type fatty acid binding protein (hFABP) is an intracellular molecule engaged in the transport of fatty acids through myocardial cytoplasm and has been used as a rapid marker of myocardial infarction. However, its value in the evaluation of perioperative myocardial injury has not yet been assessed. METHODS: 32 consecutive patients undergoing coronary artery bypass grafting were included in a prospective, randomized study using standardized operative procedures and myocardial protection. Three patients with perioperative myocardial infarction were added. Serial blood samples were taken preoperatively, before ischemia, 5 and 60 min after declamping, 1 and 6 h postoperatively and on postoperative days 1, 2 and 10 and were tested for hFABP, creatine kinase isoenzyme MB (CKMB) and troponin I (TnI). RESULTS: Hospital mortality was zero. The kinetics of the biochemical parameters revealed a typical pattern for each marker. In routine patients, hFABP levels peaked as early as 1 h after declamping, whereas CKMB and TnI peaked only 1 h after arrival in the intensive care unit. Patients with perioperative infarction displayed peak levels some hours later in all marker proteins. Peak serum levels of hFABP correlated significantly with peak levels of CKMB (r=0.436, P=0.011) and TnI (r=0.548, P=0.001), indicating the degree of myocardial damage. CONCLUSIONS: hFABP is a rapid marker of perioperative myocardial damage and peaks earlier than CKMB or TnI. The kinetics of marker proteins in serial samples immediately after reperfusion is more suitable for the detection of perioperative myocardial infarction than a fixed cut-off level.

Enhancing filtration rates by the use of blood flow around the capillaries of plasmafilters: an in vitro study.

As the low clearance rate of plasmaseparation limits its use in the treatment of patients suffering from liver failure, sepsis or MOF, we intend to develop strategies for a plasmaseparation unit which increases plasmafiltration rates. Our first question focused on whether commercially available plasmaseparation filters, and in particular their membranes, are suitable for the inversion of blood and plasma compartments. This experimental study was performed using in vitro systems. Commercially available plasmafilters PF2000N (Gambro) and Plasmaflo (Asahi) were compared in both their normal operating mode with blood flow through the capillary lumen, and in the inverse mode. Inverse mode means that blood flows through the outer space of the capillaries while plasma was obtained from the lumen. Heparinised porcine blood (5 I.U./ml) was used in a heated, recirculating in vitro circuit. Our main results were that the normal use of both filter types Plasmaflo and PF2000N enabled maximal blood flows (Qb) of 200 ml/min and filtration rates (Qf) of 25-40 ml/min. Operating the filters in the inverse mode enabled Qb up to 500 ml/min and Qf up to 100 ml/min. Hemolysis, platelet counts and coagulation parameters did not differ significantly regardless of whether the normal or inverse mode was used. The tested plasmafiltration membranes appear to be suitable for use in inverse mode. Although in our experiments, hemocompatibility tests did not indicate severe problems induced by the module geometry, the development of a module specially constructed for blood flow outside of the hollow fibers appears to be necessary in order to minimise shunts and low perfusion areas.

Lower cardiac troponin T and I results in heparin-plasma than in serum.

BACKGROUND: The use of plasma rather than serum for determination of cardiac troponins can improve turnaround time and potentially avoid incomplete serum separation that may produce falsely increased results. We investigated the influence of incomplete serum separation and the effect of heparin-plasma on cardiac troponin concentrations. METHODS: Serum and heparin-plasma samples were drawn simultaneously from 100 patients (50 patients with acute coronary syndrome and 50 patients after open heart surgery) and measured on three different analytical systems, two for determination of cardiac troponin I (cTnI; Abbott AxSYM and Bayer ACS:Centaur) and one for cardiac troponin T (cTnT; Roche Elecsys cTnT STAT). Serum samples were reanalyzed after a second centrifugation to assess the influence of incomplete serum separation. RESULTS: Mean results (+/- 95% confidence interval) in heparin-plasma compared with serum were 101% +/- 2% (AxSYM cTnI), 94% +/- 3% (ACS:Centaur cTnI), and 99% +/- 3% (Elecsys cTnT). Differences >20% were seen in 11% of results on the ACS:Centaur, 9% of results on Elecsys cTnT, and 2% of results on the AxSYM. For the Elecsys cTnT assay, the magnitude of the difference between serum and plasma was independent of the absolute concentration and confined to individual samples, and was reversed by treatment with heparinase. A second centrifugation had no effect on serum results by any of the assays. CONCLUSION: The concentrations of troponins measured in heparin-plasma are markedly lower than in serum in some cases.

Novel mechanism for presynaptic inhibition: GABA(A) receptors affect the release machinery.

Presynaptic inhibition is produced by increasing Cl(-) conductance, resulting in an action potential of a smaller amplitude at the excitatory axon terminals. This, in turn, reduces Ca(2+) entry to produce a smaller release. For this mechanism to operate, the "inhibitory" effect of shunting should last during the arrival of the "excitatory" action potential to its terminals, and to achieve that, the inhibitory action potential should precede the excitatory action potential. Using the crayfish neuromuscular preparation which is innervated by one excitatory axon and one inhibitory axon, we found, at 12 degrees C, prominent presynaptic inhibition when the inhibitory action potential followed the excitatory action potential by 1, and even 2, ms. The presynaptic excitatory action potential and the excitatory nerve terminal current (ENTC) were not altered, and Ca(2+) imaging at single release boutons showed that this "late" presynaptic inhibition did not result from a reduction in Ca(2+) entry. Since 50 microM picrotoxin blocked this late component of presynaptic inhibition, we suggest that gamma-aminobutyric acid-A (GABA(A)) receptors reduce transmitter release also by a mechanism other than affecting Ca(2+) entry.

Sudden onset of EDTA-dependent pseudothrombocytopenia after therapy with the glycoprotein IIb/IIIa antagonist c7E3 Fab.

The development of thrombocytopenia following exposure to the platelet glycoprotein (GP) IIb/ IIIa receptor antagonist abciximab (c7E3 Fab, ReoPro) is associated with adverse clinical outcome and excessive bleeding. Pseudothrombocytopenia is an important differential diagnosis in sudden onset of thrombocytopenia in a patient treated with c7E3 Fab. We report on a case of documented sudden onset of EDTA-dependent pseudothrombocytopenia in a 63-year-old woman who was admitted for emergency coronary intervention. Four hours after bolus administration of c7E3 Fab, the platelet concentration in EDTA-anticoagulated blood decreased from 385 x 10(9)/l to 119 x 10(9)/l, and it showed a further decrease to 57 x 10(9)/l at the end of a 12-h infusion. Despite no warnings or abnormalities of the automated cell counter, platelet aggregates were observed by microscopic evaluation of the blood smear. Repeated platelet counts in citrate-anticoagulated samples revealed platelet concentrations within the reference range. EDTA-dependent pseudothrombocytopenia due to therapy with c7E3 Fab is an important differential diagnosis that needs to be excluded rapidly from other causes of thrombocytopenia to avoid unnecessary further examinations, discontinuation of therapy, or even initiation of inappropriate therapy.