Two SARS-CoV-2 IgG immunoassays comparison and time-course profile of antibodies response

INTRODUCTION

The persistence of circulating antibodies to SARS-CoV-2 infection is not yet well known. We compare the results of 2 automated systems for the determination of IgG against SARS CoV-2 and assess the time-course of the IgG response.

METHODS

IgG were measured in 103 specimens of 55 patients with COVID-19 (time from the symptoms' onset: 3-187 days) using the automated tests "Abbott SARS-COV-2 IgG" and "MAGLUMI 2019-nCoV IgG".

RESULTS

The 2 methods had a concordance of 90.3%, but the quantitative correlation, although significant, showed dispersed results. All the specimens resulted positive after 17 days. However, the median concentrations of IgG rapidly increased up to 20 days and decreased for Maglumi IgG while Abbott IgG showed a constant trend up to 85 days, and then slowly declined.

CONCLUSIONS

The titer of IgG against SARS-CoV-2 may significantly and rapidly decrease, but with a very different time-course depending on the method used for the determination.

Corneal transplantation during the COVID-19 pandemic: An operational guide

PURPOSE

To provide an operational guide for corneal transplantation during the COVID-19 pandemic aimed to maintain surgery and avoid spreading of SARS-CoV-2.

METHODS

Prospective observational case series study in patients requiring corneal graft manage toward separate free and restricted pathways for those COVID-19 negative or positive, respectively.

RESULTS

During the national lockdown, 30 consecutive patients underwent endothelial (n = 16), penetrating (n = 9), and anterior lamellar keratoplasty (n = 5). Two patients followed the COVID-19 restricted pathway, as they were considered positive while waiting for test results. Nine patients were hospitalized one night in the hospital. On admission to the hospital before surgery, at surgery, the day after surgery and at 7 and 30 days all patients and health-care personnel showed no symptoms and resulted negative at risks factors/exposure to the SARS-CoV-2 infection and occurrence of COVID-19. Nucleic acid testing resulted not detectable in all patients and SARS-CoV-2 antibodies quantification showed IgG and IgM below the positive predicted value in 29 patients. One patient showed IgM above the cut-off of significance (1.21 and 1.03 preoperative and 1-month postoperative, respectively) that were considered irrelevant because of the absence of symptoms and exposure risks.

CONCLUSIONS

The concept of donor emergency (i.e. short-term availability of transplant tissues), makes corneal transplantation an always-urgent activity because it is related to the availability of the corneal tissue from a donor. Modest adjustments to ophthalmic clinic and eye surgery organization are required to maintain surgery and care of eye patients in a safe environment.

The point-of-care testing in the emergency department

The decentralization of analysis at the emergency room is a well-established practice, in particular for the use of blood gas analysis. Recently, many other analyzers have been proposed, with rapid methods that can potentially reduce the response time of the tests. Here we consider the various analyzers that can be used at the bedside, their advantages and limits, the related scientific evidences. Finally, we discuss their impact both on patient care and on accelerating the patient’s flow in the emergency room.

Comparison of Pig, Human and Rat Hepatocytes as a Source of Liver Specific Metabolic Functions in Culture Systems - Implications for Use in Bioartificial Liver Devices

The limited availability of human hepatocytes results in the use of animal cells in most bioartificial liver support devices. In the present work, clinically relevant liver specific metabolic activities were compared in rat, pig and human hepatocytes cultured on liver-derived biomatrix to optimize the expression of differentiated functions. Pig hepatocytes showed higher rates of diazepam metabolism (2.549±0.821 μg/h/million cells vs. 0.474±0.079 μg/h/million cells rats, p<0.005, and vs. 0.704±0.171 μg/h/million cells in man, p<0.005) and of bilirubin conjugation (21.60116±8.433237 μmoles/l/24 h vs. 6.786809±2.983758 in man, p<0.001 and vs. 9.956538±1.781016 μmoles/l/24 h in rats, p<0.005). Urea synthesis was similar in pig and in human hepatocytes (150±46.3 vs. 144.8±21.46 nmoles/h/million cells) and it was lower in rats (84.38±35.2; p<0.001 vs. man, p<0.02 vs. pig). High liver specific metabolic activities in cultured pig hepatocytes further support their use as a substitue for human cells in bioartificial liver devices

Combined use of the multidimensional prognostic index (MPI) and procalcitonin serum levels in predicting 1-month mortality risk in older patients hospitalized with community-acquired pneumonia (CAP): a prospective study

BACKGROUND

Several scores and biomarkers, i.e., procalcitonin (PCT), were proposed to stratify the mortality risk in community-acquired pneumonia (CAP).

AIM

Evaluating prognostic accuracy of PCT and Multidimensional Prognostic Index (MPI) for 1-month mortality risk in older patients with CAP.

METHODS

At hospital admission and at discharge, patients were evaluated by a Comprehensive Geriatric Assessment to calculate MPI. Serum PCT was measured at admission and 1, 3, and 5 days after hospital admission.

RESULTS

49 patients were enrolled. The overall 1-month mortality was 44.5 for 100-persons year. Mortality rates were higher with the increasing of MPI. In survived patients, MPI at discharge showed higher predictive accuracy than MPI at admission. Adding PCT levels to admission MPI prognostic accuracy for 1-month mortality significantly increased.

CONCLUSION

In older patients with CAP, MPI significantly predicted 1 month mortality. PCT levels significantly improved the accuracy of MPI at admission in predicting 1-month mortality.

Peripheral artery disease in type 2 diabetes: the role of fibrinolysis

The aim of the present study is to verify the relationship between peripheral artery disease (PAD) and some coagulation/fibrinolysis parameters in type 2 diabetic patients.

Sixty-three type 2 diabetic patients, without PAD, were studied at baseline and after 4 years. Assessments included tissue-Plasminogen Activator (t-PA), Plasminogen Activator Inhibitor-1 antigen (PAI-1 Ag), Plasminogen Activator Inhibitor-1 activity (PAI-1 Act), Plasminogen (Pl), Fibrin peptide A (FPA), Fibrinogen (Fr), and the ankle/brachial pressure index (ABI).

We observed a significant difference between diabetic patients and controls as regards tPA (11.8 ± 5.4 vs. 6.6 ± 3.0 ng/ml; p <0.05 ) and PAI-1 Act (17.8 ± 9.2 vs. 11.7 ± 6.6 ng/dl; p <0.005). After 4 years 13 diabetic patients became vasculo-pathic and, at baseline, had significantly lower tPA (8.9 ± 4.8 vs. 12.5 ± 5.3; p <0.011), and higher PAI-1 Ag (50.8 ± 22.2 vs. 32 ± 22.2; p <0.006), and PAI-1 Act values (24.1 ± 9.5 vs. 16.1 ± 8.4; p <0.014), compared with 50 diabetic patients who did not develop PAD after 4 years.

These data show that the physiological equilibrium which exists between t-PA and PAI-1 moves towards higher levels in our diabetic patients compared with controls, at baseline, whereas diabetic patients who developed PAD showed a shift towards an antifibrinolytic pathway with diminished t-PA, increased PAI-1 Ag and PAI-1 Act and consequently procoagulant activity. Our study suggests that hypofibrinolysis may be involved in the future onset of PAD in type 2 diabetic patients.

Abnormalities in the 24-hour rhythm of skin temperature in cirrhosis: Sleep-wake and general clinical implications

BACKGROUND & AIMS

Sleep preparation/onset are associated with peripheral vasodilatation and a decrease in body temperature. The hyperdynamic syndrome exhibited by patients with cirrhosis may impinge on sleep preparation, thus contributing to their difficulties falling asleep. The aim of this study was the assessment of skin temperature, in relation to sleep-wake patterns, in patients with cirrhosis.

METHODS

Fifty-three subjects were initially recruited, and 46 completed the study. Of the final 46, 12 were outpatients with cirrhosis, 13 inpatients with cirrhosis, 11 inpatients without cirrhosis and 10 healthy volunteers. All underwent baseline sleep-wake evaluation and blood sampling for inflammatory markers and morning melatonin levels. Distal/proximal skin temperature and their gradient (DPG) were recorded for 24 hours by a wireless device. Over this period subjects kept a sleep-wake diary.

RESULTS

Inpatients with cirrhosis slept significantly less well than the other groups. Inpatients and outpatients with cirrhosis had higher proximal temperature and blunted rhythmicity compared to the other groups. Inpatients with/without cirrhosis had higher distal temperature values and blunted rhythmicity compared to the other groups. Inpatients and outpatients with cirrhosis had significantly lower DPG values compared to the other groups, and DPG reached near-zero values several hours later. Significant correlations were observed between temperature and sleep-wake variables and inflammatory markers.

CONCLUSIONS

Alterations of distal/proximal skin temperature, their gradient and their time-course were observed in patients with cirrhosis, which may contribute to their sleep disturbances.

Laboratory testing in the emergency department: An Italian Society of Clinical Biochemistry and Clinical Molecular Biology (SIBioC) and Academy of Emergency Medicine and Care (AcEMC) consensus report

The mainstay of patient-oriented laboratory testing in emergency settings entails selecting number and type of tests according to valid criteria of appropriateness. Since the pattern of urgent tests requesting is variable across different institutions, we designed a joined survey between the Academy of Emergency Medicine and Care (AcEMC) and the Italian Society of Clinical Biochemistry and Clinical Molecular Biology (SIBioC) for reaching tentative consensus about the most informative diagnostic tests in emergency settings. A survey, containing the most commonly performed urgent laboratory tests and the relative clinical indications, was disseminated to eight relevant members of AcEMC and eight relevant members of SIBioC. All contributors were asked to provide numerical scores for the different laboratory parameters, where 1 indicated <em>strongly recommended</em>, 2 <em>recommended in specific circumstances</em>, and 3 <em>strongly discouraged</em>. The mean results of the survey were presented as the mean of responders’ values, and the parameters were finally classified as <em>strongly recommended</em> (mean value, 1.0-1.5), <em>somehow recommended</em> (mean value, 1.5-2.0), <em>discouraged</em> (mean value, 2.0-2.5) and <em>strongly discouraged</em> (mean value, 2.5-3.0). The results of the survey allowed defining a hierarchy of priority, wherein 24 tests were <em>strongly recommended</em>. The use of 5 common tests was instead <em>strongly discouraged</em>. For 16 additional parameters in the list, the consensus ranged between <em>somehow recommended</em> and <em>discouraged</em>. We hope that results presented in this joint AcEMC-SIBioC consensus document may help harmonizing panel of tests and requesting patters in emergency setting, at least at a national level.

Laboratory testing in the emergency department: an Italian Society of Clinical Biochemistry and Clinical Molecular Biology (SIBioC) and Academy of Emergency Medicine and Care (AcEMC) consensus report

Background:

The mainstay of patient-oriented laboratory testing in emergency settings entails selecting a number and the type of tests according to valid criteria of appropriateness. Since the pattern of urgent tests requesting is variable across different institutions, we designed a joined survey between the Academy of Emergency Medicine and Care (AcEMC) and the Italian Society of Clinical Biochemistry and Clinical Molecular Biology (SIBioC) for reaching tentative consensus about the most informative diagnostic tests in emergency settings.

Methods:

A survey, containing the most commonly ordered urgent laboratory tests and the relative clinical indications, was disseminated to eight relevant members of AcEMC and eight relevant members of SIBioC. All contributors were asked to provide numerical scores for the different laboratory parameters, where 1 indicated “strongly recommended”, 2 “recommended in specific circumstances”, and 3 “strongly discouraged”. The mean results of the survey were presented as the mean of responders’ values, and the parameters were finally classified as “strongly recommended” (mean value, 1.00–1.49), “weakly recommended” (mean value, 1.50–1.99), “discouraged” (mean value, 2.00–2.49) and “strongly discouraged” (mean value, 2.50–3.00).

Results:

The results of the survey allowed defining a hierarchy of priority, wherein 24 tests were “strongly recommended”. The use of five common tests was instead “strongly discouraged”. For 16 additional parameters in the list, the consensus ranged between “weakly recommended” and “discouraged”.

Conclusions:

We hope that results presented in this joint AcEMC-SIBioC consensus document may help harmonizing panel of tests and requesting patterns in emergency setting, at least at a national level.

Poor comparability of coagulation screening test with specific measurement in patients receiving direct oral anticoagulants: results from a multicenter/multiplatform study

Essentials Prothrombin and partial thromboplastin time (PT/PTT) measure direct oral anticoagulants (DOACs). PT, PTT and specific tests for DOACs were performed on patients treated for atrial fibrillation. Normal PT/PTT don't exclude DOAC activity and their prolongation doesn't confirm DOAC action. The use of PT or PTT to evaluate DOAC activity could cause dangerous misinterpretations.

SUMMARY

Background Prothrombin time (PT) and activated partial thromboplastin time (APTT) have been proposed to measure the effect of oral anti-activated factor X (FXa) or anti-activated FII drugs, respectively. Aims To evaluate the relationships and responsiveness of PT and APTT versus direct oral anticoagulant (DOAC) concentrations measured with specific coagulation tests performed with different platforms in four Italian anticoagulation clinics. Methods Six hundred and thirty-five patients with atrial fibrillation participated in the study: 240 were receiving dabigatran, 264 were receiving rivaroxaban, and 131 were receiving apixaban. Blood was taken at trough and peak within the first month (15-25 days) of treatment. PT, APTT, diluted thrombin time (dTT) calibrated for dabigatran and anti-FXa calibrated for rivaroxaban or apixaban were determined. Results For dabigatran, the correlation between APTT and dTT ranged from r = 0.80 to r = 0.62. For rivaroxaban, the correlation between the anti-FXa assay and PT ranged from r = 0.91 to r = 0.73. For apixaban, the correlation between the anti-FXa assay and PT was lower than for the two other drugs (r = 0.81 to r = 0.54). Despite the above significant correlations, the responsiveness of PT or APTT was relatively poor. A discrepancy between global testing and DOAC plasma concentrations was shown in a considerable proportion of patients, depending on the platform and drug, with values ranging from 6% to 62%. Conclusions Overall, poor responsiveness of the screening tests to DOAC concentrations was observed. PT and APTT normal values cannot exclude DOAC anticoagulant activity, and PT or APTT prolongation is not always associated with DOAC anticoagulant effect as determined with specific tests.

Urgent Thyroid-Stimulating Hormone Testing in Emergency Medicine: A Useful Tool?

BACKGROUND

Thyroid-stimulating hormone (TSH) has recently been introduced among the tests available to the Emergency Department (ED) of our hospital.

OBJECTIVE

To evaluate the prevalence of TSH-level-dependent thyroid dysfunction and to assess the usefulness of urgent TSH testing in a series of emergency patients.

METHODS

We planned a single-center observational cross-sectional clinical study. We divided patients in groups according to their thyroid status using defined TSH decision levels. Previously diagnosed history of thyroid dysfunction and newly diagnosed thyroid dysfunctions were differentiated. Further, we analyzed the subset of emergency patients affected by atrial fibrillation (AF) due to the role of hyperthyroidism in AF pathogenesis. For each TSH request, we made a retrospective chart review to assess the usefulness of the test based on clinical efficacy and management efficiency indicators.

RESULTS

The present study showed that, although the overall thyroid dysfunction rate was higher than in the general population, only a few newly diagnosed thyroid dysfunctions were found with limited clinical utility. We categorized urgent TSH requests as useful and not useful, by retrospective evaluation, and we identified and compared the main TSH testing clinical indications in the two groups.

CONCLUSION

We found a positive impact of urgent TSH determination in emergency decision-making. Nevertheless, a stronger clinical impact could be achieved by improving request appropriateness and by targeting TSH testing to some clinical indications identified by the study. The work was considered a quality-improvement project by the Hospital Committee for Quality Management.

An international study of how laboratories handle and evaluate patient samples after detecting an unexpected APTT prolongation

An unexpectedly detected prolonged activated partial thromboplastin time (APTT) can be a harmless laboratory finding, but can also reflect a thrombotic tendency or a bleeding disorder. The assistance of laboratory professionals in the interpretation of an unexpectedly detected prolonged APTT (uAPTT) is often required. The way in which uAPTTs are evaluated in laboratories was assessed in this international study with the aim of determining whether laboratory professionals are able to fulfill this need.

Postanalytical practices after uAPTT were investigated and the mixing study methodology (if used) was studied by circulating a case report with a questionnaire to staff in the invited laboratories. In addition, the interpretations of those staff regarding the presence or absence of inhibitors in three APTT mixing study scenarios were examined.

Large within- and between-country variations were detected in both postanalytical practices and mixing study methodologies among the 990 responding laboratories, 90% of which were in 13 countries. Shortcomings regarding the investigation of uAPTTs leading to potentially incorrect or delayed clinical diagnoses were found in 88% of the laboratories. Of the laboratories to which the interpretative questions were sent, 49% interpreted all mixing study scenarios correctly. uAPTTs were investigated appropriately and all mixing study scenarios interpreted correctly in parallel in only 9.6% of the participating laboratories.

The clinical requirement for the assistance of laboratory professionals in the interpretation of uAPTTs cannot be met at most of the participating laboratories. Laboratory professionals should be trained in the evaluation of ordinary laboratory tests, such as that for uAPTTs.

Age and gender specific cut-off values to improve the performance of D-dimer assays to predict the risk of venous thromboembolism recurrence

The Prolong study shows that continuing vitamin K antagonists (VKA) in patients with abnormal D-dimer (evaluated by a qualitative assay, Clearview Simplify D-dimer) results in a significant reduction of venous thromboembolism (VTE) recurrence. The present study retrospectively analyzes a subgroup of patients enrolled in the Prolong study with a view to calculate cut-off values for six quantitative D-dimer methods to predict the risk of VTE recurrence. We measured D-dimer levels by VIDAS D-dimer Exclusion (bioMerieux), STA Liatest D-dimer (DiagnosticaStago), HemosIL D-dimer and HemosIL D-dimer HS (Instrumentation Laboratory), Innovance D-dimer (Siemens) and AutoDimer (Trinity Biotech) in frozen plasma aliquots sampled 30 ± 10 days after VKA cessation in 390 patients enrolled in the Prolong study. During follow-up (562.7 years), 28 patients had recurrent VTE (7.2%, 5.0% person-years). Since D-dimer levels are positively correlated with age and significantly lower in men, we calculated method-specific cut-off values according to age and gender. The HRs for VTE recurrence calculated using method-specific cut-off values based on age and gender are higher than those using cut-off values indicated by the manufacturers for VTE exclusion in symptomatic outpatients. These data suggest that method-specific cut-off values calculated according to patient age and gender can be more accurate in identifying patients at a higher risk for VTE recurrence. These method-specific cut-off values are being evaluated in the ongoing prospective management multicenter DULCIS study.

Increased anticoagulant response to low-molecular-weight heparin in plasma from patients with advanced cirrhosis

INTRODUCTION

Cirrhotic patients may present thrombotic complications that warrant anticoagulant therapy. However, the efficacy of low-molecular-weight heparin (LMWH) in this clinical setting is still unclear.

AIMS/METHODS

To evaluate the in vitro effect of LMWH on thrombin generation (TG) in cirrhotic patients at different stages of liver disease. Thirty cirrhotics (10 Child Pugh A, 10 Child Pugh B and 10 Child Pugh C), 10 subjects with inherited type 1 antithrombin (AT) defect and 10 healthy controls were studied. TG was determined at baseline and with anti-Xa levels after the addition of enoxaparin at 0.35 and 0.7 U anti-Xa mL. The endogenous thrombin potential (ETP) ratio at 0.35 and 0.7 U anti-Xa mL was obtained by dividing ETP with LMWH by ETP at baseline.

RESULTS

Mean AT levels in all cirrhotic subgroups and in patients with AT deficiency were significantly lower than in controls. The 0.35 ETP ratio was significantly lower in cirrhotic patients than in controls (0.26 ± 0.1 vs. 0.48 ± 0.1, P < 0.001) and the reduction paralleled the severity of liver disease, in spite of the concomitant decrease in AT and anti-Xa activity. AT-deficient subjects showed a significantly increased 0.35 ETP ratio compared with both cirrhotic patients and controls (0.69 ± 1 vs. 0.26 ± 0.1, P < 0.001, and vs. 0.48 ± 0.1, P = 0.04 respectively). LMWH at 0.7 U anti-Xa mL completely inhibited TG in 9/30 cirrhosis patients with more advanced liver disease (Child Pugh B and C), whereas complete TG abolition was seen in only 1/10 controls.

CONCLUSIONS

Cirrhotic patients show an increased response to LMWH, which correlates with the severity of liver disease, in spite of reduced AT and anti-Xa activity levels. Thrombin generation may be a useful tool to monitor the response to LMWH in cirrhotic patients.

Exploring the Initial Steps of the Testing Process: Frequency and Nature of Pre-Preanalytic Errors

BACKGROUND

Few data are available on the nature of errors in the so-called pre-preanalytic phase, the initial steps of the testing process. We therefore sought to evaluate pre-preanalytic errors using a study design that enabled us to observe the initial procedures performed in the ward, from the physician's test request to the delivery of specimens in the clinical laboratory.

METHODS

After a 1-week direct observational phase designed to identify the operating procedures followed in 3 clinical wards, we recorded all nonconformities and errors occurring over a 6-month period. Overall, the study considered 8547 test requests, for which 15 917 blood sample tubes were collected and 52 982 tests undertaken.

RESULTS

No significant differences in error rates were found between the observational phase and the overall study period, but underfilling of coagulation tubes was found to occur more frequently in the direct observational phase (P = 0.043). In the overall study period, the frequency of errors was found to be particularly high regarding order transmission [29 916 parts per million (ppm)] and hemolysed samples (2537 ppm). The frequency of patient misidentification was 352 ppm, and the most frequent nonconformities were test requests recorded in the diary without the patient's name and failure to check the patient's identity at the time of blood draw.

CONCLUSION

The data collected in our study confirm the relative frequency of pre-preanalytic errors and underline the need to consensually prepare and adopt effective standard operating procedures in the initial steps of laboratory testing and to monitor compliance with these procedures over time.

Different biochemical correlates for different neuropsychiatric abnormalities in patients with cirrhosis

The diagnosis of hepatic encephalopathy (HE) relies on clinical, neurophysiological, psychometric and laboratory variables. The relationships between such tests remain debated. The aim of this study was to determine the laboratory correlates/prognostic value of neurophysiological/psychometric abnormalities in patients with cirrhosis. Seventy-two patients and 14 healthy volunteers underwent EEG and paper-and-pencil psychometry (PHES). Blood was obtained for C reactive protein (CRP), interleukin 6 (IL6), tumor necrosis factor (TNF)α, ammonia and indole/oxindole. Patients were followed prospectively for a median of 22 months in relation to the occurrence of death, transplantation and HE-related hospitalizations. Thirty-three patients had normal PHES and EEG, 6 had abnormal PHES, 18 abnormal EEG and 13 abnormal PHES and EEG. Patients with abnormal PHES had higher CRP (17 ± 22 vs 7 ± 6, P < 0.01), IL6 (32 ± 54 vs 12 ± 13, P < 0.05) and TNFα (17 ± 8 vs 11 ± 7, P < 0.001) levels than those with normal PHES. Patients with abnormal EEG had higher indole (430 ± 270 vs 258 ± 255, P < 0.01) and ammonia (66 ± 35 vs 45 ± 27, P < 0.05) levels than those with normal EEG. Psychometric test scores showed significant correlations with CRP, TNFα and IL6; EEG indices with ammonia and IL6. CRP and TNFα concentrations were independent predictors of abnormal PHES, ammonia and indole of abnormal EEG on multivariate analysis. Seven patients were lost to follow-up; of the remaining 65, 20 died and 14 underwent transplantation; 15 developed HE requiring hospitalization. PHES and EEG performance were independent predictors of HE and death (P < 0.05).

CONCLUSION

PHES and EEG abnormalities in patients with cirrhosis have partially different biochemical correlates and independently predict outcome.

Post-analytical errors with portable glucose meters in the hospital setting

Point-of-care testing (POCT) for blood glucose is widely used in different clinical settings and, thanks to its rapid turnaround time (TAT), it is commonly recommended in patients with critical conditions calling for urgent monitoring. However data in the literature on its reliability and safety are scarce. The aim of the present study was therefore to investigate the type, frequency and clinical risks associated with POCT using portable glucose meters in the hospital setting by evaluating the post-analytical phase when the data are manually transcribed in patients' record. We checked all registrations performed by nurses of 2 selected wards of the hospital during a period of 30 consecutive days, identifying 1966 blood glucose determinations. We found that data obtained were often not reported in patients' files (12.1% of results are missed), the time of blood sampling was recorded in imprecise manner in 7.2% of cases and the glucose concentration was incorrectly reported in 3.2% of results. Although in the post-analytical phase the frequency of incomplete or incorrect data was high, no adverse events were found to be related to this type of error.

Clinical impact of false-negative sentinel lymph nodes in breast cancer

AIMS

To evaluate the incidence of false-negative (FN) sentinel lymph node (SLN) cases, their correlation with a series of clinico-pathologic parameters and their impact on adjuvant treatment indications and on clinical axillary relapse in the setting of a multicentric clinical trial comparing SLN biopsy with axillary lymph node dissection (ALND).

METHODS

A series of 697 patients with primary breast cancer < or = 3 cm were randomized to SLN biopsy associated with ALND (ALND arm) or to SLN biopsy followed by ALND only if the SLN was metastatic (SLN arm). The FN SLN rate was assessed in the ALND arm. A series of 11 clinico-pathological parameters were tested for a possible association with FN results. The indications for adjuvant treatments were evaluated by considering both the FN nodal stages, as indicated by the SLN, and the true positive axillary status, as indicated by completion ALND. The occurrence of clinically evident axillary recurrences was evaluated in the two arms.

RESULTS

The FN rate was 16.7%. Of the clinico-pathologic parameters tested, only a tumour size < or = 2 cm and the presence of a single metastatic axillary node was significantly associated with a risk of FN (p = 0.033 and p = 0.018, respectively). The FN SLN would have led to different adjuvant therapy indications in 12/18 cases. At 56 months, no clinically evident axillary nodal recurrences were present in the ALND arm patients, whereas one case of axillary recurrence was detected in the SLN arm patients.

CONCLUSIONS

FN SLN biopsy is not uncommon, especially in the presence of a small primary tumour with a single nodal metastasis. An FN finding can lead to less than optimal adjuvant treatment. However, the clinical impact of FN in terms of axillary recurrence at 56 months was minimal.

Morbidity comparison of sentinel lymph node biopsy versus conventional axillary lymph node dissection for breast cancer patients: Results of the sentinella–GIVOM Italian randomised clinical trial

AIMS

To compare physical morbidity and health-related quality of life (HRQOL) in breast cancer patients who received standard axillary dissection (ALND) or sentinel lymph node biopsy (SLNB), followed by axillary dissection only in the case of sentinel-node positivity, within a randomised clinical trial.

PATIENTS AND METHODS

Patients with early breast cancer < or =3cm and clinically negative axilla were randomly allocated to ALND or SLNB. All patients underwent physical examination every 6 months in order to assess any arm-related symptoms. A subset of patients completed the SF-36 quality of life questionnaire and the Psychological General Well Being Index (PGWBI) before randomisation, at 6 and 12 months after surgery and yearly thereafter. Results of the first 24 months are reported.

RESULTS

Six-hundred and seventy-seven patients were available for analysis: 341 patients randomised to the ALND group and 336 to the SLNB group. Six months after surgery, the SLNB group had significantly less lymph-oedema, movement restrictions, pain and numbness with respect to the ALND group. Lymph-oedema was also significantly reduced at 12 months and numbness remained significantly less frequent in the SLNB arm at all time points. Three-hundred and ten patients participated in the HRQOL assessment. The mean scores of the PGWB questionnaire general index and anxiety domain were significantly better in the SLNB group than in the ALND group but the difference ceased to be significant at 24 months.

CONCLUSIONS

The SLNB is associated with reduced arm morbidity without evidence of a negative impact on psychological well being. While waiting for long-term results of ongoing randomised clinical trials, the SLNB may be proposed for early stage breast cancer patients after adequate information on the expected advantages and the possible risks.

Errors in a Stat Laboratory: Types and Frequencies 10 Years Later

Background: In view of increasing attention focused on patient safety and the need to reduce laboratory errors, it is important that clinical laboratories collect statistics on error occurrence rates over the whole testing cycle, including pre-, intra-, and postanalytical phases.

Methods: The present study was conducted in 2006 according to the design we previously used in 1996 to monitor the error rates for laboratory testing in 4 different departments (internal medicine, nephrology, surgery, and intensive care). For 3 months, physicians and nurses were asked to pay careful attention to all test results. Any suspected laboratory error was recorded with associated pertinent clinical information. Every day, a laboratory physician visited the 4 departments and a critical appraisal was made of any suspect results.

Results: Among a total of 51 746 analyses, clinicians notified us of 393 questionable findings, 160 of which were confirmed as laboratory errors. The overall frequency of errors, 3092 ppm, was significantly lower (P &lt;0.05) than in 1996 (4700 ppm). Of the 160 confirmed errors, 61.9% were preanalytical errors, 15% were analytical, and 23.1% were postanalytical.

Conclusions: During the last decade the error rates in our stat laboratory have been reduced significantly. As demonstrated by the distribution pattern, the pre- and postanalytical steps still have the highest error prevalences, but changes have occurred in the types and frequencies of errors in these phases of testing.

Metabolic activity of rat hepatocytes cultured on homologous acellular matrix and transplanted into Gunn rats

The metabolic activity of hepatocytes cultured on homologous acellular matrix (HAM) and transplanted into rats genetically incapable of bilirubin conjugation (Gunn rats) has been investigated. Hepatocytes from Wistar male rats were seeded on HAM and cultured for 9 days, and the proliferation rate and albumin mRNA expression were assayed daily. HAM alone or HAM plus hepatocytes (cultured for 3 days) were implanted in a subcutaneous pocket of the dorsal region of Gunn rats. No immunosuppression therapy was used. Blood samples were collected weekly and rats were sacrificed 10 weeks after surgery. Hepatocytes cultured on HAM displayed a higher proliferation rate than those cultured on plastic, and albumin mRNA expression was detected in hepatocytes seeded on HAM, but not on plastic. Serum bilirubin concentrations did not differ from baseline values in both the sham-operated control and HAM transplanted rats. On the contrary, in rats transplanted with HAM plus hepatocytes, circulating bilirubin levels decreased from week 4-7, and then plateaued until week 10. Histology did not evidence signs of rejection, but only a mild degree of inflammation around the implanted patches. It is concluded that hepatocytes seeded on HAM and transplanted into Gunn rats are able to metabolize bilirubin for at least two months, without signs of rejection even in the absence of immunosuppressive therapy.

Effects of Long-term Administration of High-dose Recombinant Human Antithrombin in Immunosuppressed Primate Recipients of Porcine Xenografts

BACKGROUND

Fibrin deposition is central to the acute humoral rejection process occurring in the presence of consumptive coagulopathy when pig organs are transplanted into primates.

METHODS

To assess whether strategies aimed at preventing fibrin formation may extend xenograft survival, we administered high daily doses of recombinant human antithrombin (rhAT) (500 U/kg twice daily) to obtain both anticoagulant and anti-inflammatory effects in immunosuppressed primate recipients of porcine kidneys.

RESULTS

Some degree of consumptive coagulopathy developed in both rhAT-treated (n=3) and untreated (n=3) primates. No major differences in the coagulation parameters analyzed were observed between the 2 groups. Similarly, no difference in survival was seen between rhAT-treated (20.6+/-4 days; range: 15-23 days) and untreated animals (17.3+/-11.6 days; range: 7-30 days), although the rhAT-treated primates had a higher bleeding tendency. Despite the high daily dose of rhAT, considerable fibrin deposition was observed in the graft as early as 2 weeks after transplantation.

CONCLUSIONS

These results suggest that a high daily dose of rhAT fails to influence survival or prevent fibrin formation and deposition in the graft in our pig-to-primate model. However, the potential role of rhAT administered in combination with heparins or other clotting inhibitor concentrates in this model remains to be determined.

Syngeneic living-donor liver transplantation for hemangioendothelioma: a clinical model for studying liver regeneration

A 22-year-old Caucasian patient underwent living-donor liver transplantation (LDLT) for hepatic hemangioendothelioma in a healthy liver. The organ donor was his monozygotic twin brother. Surgery was uneventful in both donor and recipient, who received the same postoperative treatment (i.e. no immunosuppression for the recipient). Although both donor and recipient achieved a full liver function recovery, the volume of the recipient's graft increased much more than the donor's residual liver in the first postoperative month (1.6-fold vs. 1.2-fold). This different growth rate correlated with growth hormone (GH)/insulin growth factor (IGF) axis dynamics: the donor had significantly lower insulin-like growth factor 1 (IGF-1), insulin-like growth factor 2 (IGF-2) and insulin-like growth factor binding protein 3 (IGFBP-3) values than the recipient on postoperative days (POD) 3-30, although they had similar GH values. Other potential regenerative factors, e.g. tumor necrosis alpha, interleukin 6 (IL-6), insulin and C peptide did not correlate with liver regeneration rate. The particular endocrine picture of the graft may be explained by a modified GH-hepatocyte interaction due to cold ischemia during preservation resulting in a higher IGF production. Whether this is a potential molecular tool by means of which transplanted partial livers promote their regeneration remains to be seen in a larger number of patients.

Isolated hepatocyte transplantation for Crigler-Najjar syndrome type 1

Crigler-Najjar syndrome type 1 (CN1) is an inherited disorder characterized by the absence of hepatic uridine diphosphoglucuronate glucuronosyltransferase (UDPGT), the enzyme responsible for the conjugation and excretion of bilirubin. We performed allogenic hepatocyte transplantation (AHT) in a child with CN1, aiming to improve bilirubin glucuronidation in this condition. A 9-year-old boy with CN1 was prepared with plasmapheresis and immunosuppression with prednisolone and tacrolimus. When a graft was made available, 7.5 x 10(9) hepatocytes were isolated and infused into the portal vein percutaneously. After 2 weeks phenobarbitone was added to promote the enzymatic activity of UDPGT of the transplanted hepatocytes. Nocturnal phototherapy was continued throughout the studied period. Total bilirubin was considered a reliable marker of allogenic cell function. There was no significant variation of vital signs nor complications during the infusion. Mean +/- SD bilirubin level was 530 +/- 38 micromol/L before and 359 +/- 46 micromol/L after AHT (t-test, p < 0.001). However, the introduction of phenobarbitone was followed by a drop of tacrolimus level with increase of alanine aminotransferase (ALT) and increase of bilirubin. After standard treatment of cellular rejection bilirubin fell again but from then on it was maintained at a greater level. After discharge the patient experienced a further increase of bilirubin that returned to predischarge levels after readmission to the hospital. This was interpreted as poor compliance with phototherapy. Only partial correction of clinical jaundice and the poor tolerability to nocturnal phototherapy led the parents to refuse further hepatocyte infusions and request an orthotopic liver transplant. After 24 months the child is well, with good liver function on tacrolimus and prednisolone-based immunosuppression. Isolated AHT, though effective and safe, is not sufficient to correct CN1. Maintenance of adequate immunosuppression and family compliance are the main factors hampering the success of this procedure.

Clinical significance of alpha-fetoprotein mRNA in blood of patients with hepatocellular carcinoma

BACKGROUND

Alpha-fetoprotein (AFP) messenger RNA (mRNA) in the blood reflects the presence of circulating hepatocellular carcinoma (HCC) cells and is a sensitive marker of HCC extrahepatic metastases. The specificity of this molecular marker and its correlation with the main HCC clinical-pathological parameters remains controversial, however.

METHODS

AFPmRNA was determined in 50 HCC patients and in 50 patients with diagnosis of cirrhosis (6), or colon (24) or, pancreatic (20) carcinoma. HCC patients with clinically evident extrahepatic metastasis were excluded. HCC diagnosis was confirmed in all patients by histology on percutaneous biopsies or surgical specimens; pathological grading was assessed at the same time.

RESULTS

AFPmRNA was positive in 20 HCC patients (40%) and in 18 patients without HCC (36%). The presence of AFPmRNA in the blood correlated significantly with cholestatic indices (p<0.01), nodule size (p=0.03), vascular invasion (p=0.006) and moderately or poorly differentiated HCC (p<0.0001). Moreover, survival analysis showed a significant impact of AFPmRNA detection on overall (p=0.04) and recurrence-free survival (p=0.0007) after a median follow-up of 17 months.

CONCLUSIONS

Although AFPmRNA is frequently detected in the blood, even in benign liver diseases or gastroenteric tumors, in HCC patients without clinical evidence of extrahepatic metastases it seemed to identify the biologically more aggressive tumors.

An experimental swine model of small bowel cross transplantation

AIM

In this study we evaluated the possibility of performing a cross small bowel transplantation (CrSBTx) in which, at the same time, 2 pigs were both donors and later recipients of intestinal grafts. The hemodynamic and metabolic impact of this original transplantation model on the animals was determined.

METHODS

Ten large White adult female pigs underwent a 2 stage procedure. The principal intraoperative hemodynamic and metabolic parameters were measured at different times during the operation. In the 3 days that followed the operation, renal function, liver and pancreatic damage were investigated.

RESULTS

Our surgical model permits us to keep excellent hemodynamic and metabolic stability with low mortality.

CONCLUSION

The need of half of animals with respect to conventional models represents an ethical and economic advantage of CrSBTx and we propose it for intestinal transplant studies in large animals.

Hepatocyte transplantation in the treatment of acute liver failure: microencapsulated hepatocytes versus hepatocytes attached to an autologous biomatrix

A liver transplant is considered today to be the only effective therapeutic solution for many otherwise intractable hepatic disorders. However, liver transplantation is beset by shortage of donors. Over the years, many liver support systems have been developed to supply the liver functions, mostly as a bridge to transplantation. Transplantation of isolated hepatocytes (HcTx) instead of whole liver has constituted one of the most appealing possibilities to treat several diseases. We compared two different models of HcTx in a surgical model of acute liver failure in pigs, using microencapsulated hepatocytes (MHcTx) and hepatocytes attached to a porcine biomatrix (PBMHcTx), both transplanted into peritoneum. The collected data were survival, laboratory findings, hemodynamic parameters, light microscopy, histology, MTT, and glycogen content. The group with PBMHcTx has a better outcome than the group with MHcTx (p < 0.05). Histology showed normal morphology of the hepatocytes, high glycogen content, 75% viability, positive MTT, and 95% adhesion of the hepatocytes to the biomatrix. Our biomatrix (PBM) provides cell-to-cell contact and interaction with extracellular matrix, which have been shown to play major roles in hepatocyte survival and physiologic regulation of gene expression, and guarantee a prompt engraftment and an adequate neovascularization. PBMHcTx is a useful method to treat acute liver failure and it indicates a possible liver-direct gene therapy in the treatment of inherited and acquired disorders.

Methotrexate for immunosuppression in life-supporting pig-to-cynomolgus monkey renal xenotransplantation

Methotrexate (MTX) has been used successfully as an immunosuppressant in rodent xenotransplantation models, but the data generated so far with MTX in pig-to-baboon cardiac transplantation studies have been disappointing. The potential of this agent was consequently explored in a life-supporting pig-to-primate renal model using the cynomolgus monkey as the recipient species. Introductory in vitro and in vivo pharmacokinetic and pharmacodynamic studies with MTX were conducted in three cynomolgus monkeys. Subsequently, 10 cynomolgus monkey recipients of a life-supporting kidney from human decay-accelerating factor transgenic pigs were administered MTX intravenously according to three different regimens. All the animals also received cyclosporine A and steroids. In addition, mycophenolate sodium (MPS) was administered post-operatively in two of the three groups of transplanted animals. At clinically relevant concentrations, MTX is able in vitro to inhibit the mixed lymphocyte reactions (MLR) in cynomolgus monkeys. After intravenous administration, moreover, exposure of cynomolgus monkeys to MTX appeared to be higher than had been previously reported in baboons. Graft function was observed in the transplanted animals, which survived from 0 to 41 days. All but two animals revealed acute humoral rejection in the explanted graft and developed diarrhea. Diarrhea was the cause of euthanasia in five cases. It was unrelated to the administration of MPS and associated with severe histopathological signs of enteritis. This study demonstrates that the pharmacokinetic and pharmacodynamic profiles if MTX vary substantially between non-human primate species. In vitro, MTX has immunosuppressive properties in the cynomolgus monkey at clinically relevant concentrations. In vivo, MTX has a very narrow therapeutic window in cynomolgus monkeys, however, as it does in baboons. We conclude that MTX is scarcely effective as an immunosuppressant, be it for induction or maintenance, in pig-to-cynomolgus monkey renal xenotransplantation.

Appropriateness of choice and interpretation of tests for thrombophilic defects: a practical experience

BACKGROUND

The use of laboratory coagulation tests in some fields of primary medicine is not well defined in available guidelines. In Italy, general practitioners tend to lack a thorough understanding of the utility of knowledge of coagulation inhibitors.

METHODS

We reviewed the clinical conditions for which outpatients have been referred to our laboratory for antithrombin testing or for inherited thrombophilia tests panels over a 3-week period. Evidence-based guidelines were used to identify the appropriate requests.

RESULTS

Numerous unnecessary tests were requested for both antithrombin and thrombophilia, particularly in obstetric and gynaecological situations in the setting of hormonal contraceptive treatment.

CONCLUSIONS

Laboratory specialists must improve upon their communication with physicians in order to achieve an appropriate use of coagulation tests.

Guidelines for the laboratory investigation of inherited thrombophilias. Recommendations for the first level clinical laboratories

Recent advances in the laboratory diagnostic approach to inherited thrombophilia call for an update on laboratory strategies and organization. The present paper therefore deals in particular with: the panel test choice, timing and test appropriateness, and analytical methods in several clinical conditions. Specific recommendations are supported by the state-of-the-art in this branch.

Peripheral artery disease in type 2 diabetes: the role of fibrinolysis

The aim of the present study is to verify the relationship between peripheral artery disease (PAD) and some coagulation/fibrinolysis parameters in type 2 diabetic patients. Sixty-three type 2 diabetic patients, without PAD, were studied at baseline and after 4 years. Assessments included tissue-Plasminogen Activator (t-PA), Plasminogen Activator Inhibitor-1 antigen (PAI-1 Ag), Plasminogen Activator Inhibitor-1 activity (PAI-1 Act), Plasminogen (Pl), Fibrin peptide A (FPA), Fibrinogen (Fr), and the ankle/brachial pressure index (ABI). We observed a significant difference between diabetic patients and controls as regards tPA (11.8 +/- 5.4 vs. 6.6 +/- 3.0 ng/ml; p <0.05) and PAI-1 Act (17.8 +/- 9.2 vs. 11.7 +/- 6.6 ng/dl; p <0.005). After 4 years 13 diabetic patients became vasculopathic and, at baseline, had significantly lower tPA (8.9 +/- 4.8 vs. 12.5 +/- 5.3; p <0.011), and higher PAI-1 Ag (50.8 +/- 22.2 vs. 32 +/- 22.2; p <0.006), and PAI-1 Act values (24.1 +/- 9.5 vs. 16.1 +/- 8.4; p <0.014), compared with 50 diabetic patients who did not develop PAD after 4 years. These data show that the physiological equilibrium which exists between t-PA and PAI-1 moves towards higher levels in our diabetic patients compared with controls, at baseline, whereas diabetic patients who developed PAD showed a shift towards an antifibrinolytic pathway with diminished t-PA, increased PAI-1 Ag and PAI-1 Act and consequently procoagulant activity. Our study suggests that hypofibrinolysis may be involved in the future onset of PAD in type 2 diabetic patients.

Cytokines and liver failure: modification of TNF- and IL-6 in patients with acute on chronic liver decompensation treated with Molecular Adsorbent Recycling System (MARS)

Liver transplantation, considered today as the most effective treatment for end-stage liver diseases, can not always be performed on every patient affected with a liver disease. Patients with end-stage liver diseases, usually have high bilirubin, encephalopathy and renal failure. In these situations cytokines play an important role in different processes, from apoptosis to regeneration. The aim of this clinical study has been to analyse the action of new artificial liver system, called Molecular Adsorbent Recycling System (MARS) on cytokines metabolism in patients affected with acute on chronic liver failure. The results are intriguing because an increase of IL-6 and a decrease of TNF-alpha observed during MARS treatment. The study confirms the efficacy of MARS therapy in terms of homeostasis of the cytokines network and suggests an usefulness of monitoring their level during liver failure.

Development of a new bioartificial liver using a porcine autologous biomatrix as hepatocyte support

Long-term maintenance of hepatocyte viability and differentiated function expression is crucial for bioartificial liver support. The maintenance of hepatocyte function in a bioreactor is still a problem. A major advance was the recognition that hepatocytes in attachment cultures can maintain their differentiation longer. To restore hepatocyte polarity and prolong their function, we developed a new bioreactor with a cross-flow geometry configuration and an original hepatocyte extracellular autologous biomatrix (Porcine Bio-Matrix) support. To test this new bioreactor, we compared it with a standard bioartificial liver cartridge in a suitable surgical model of acute liver failure in pigs. In our model, we performed a total hepatectomy, followed by partial liver transplantation after an 18 hour anhepatic phase. The results showed that the bioreactor containing the biomatrix was able to bridge the animal to transplantation and to sustain the transplanted liver until all function recovered (80% of animals survived, p = 0.0027). No animal survived more than 24 hours after liver transplantation in the group treated with the traditional bioartificial liver, whereas hepatocyte viability on the Porcine Bio-Matrix was 65% after 12 hours of treatment. The results suggest that our biomatrix is a suitable cell support and guarantees long-term maintenance of metabolic activity of hepatocytes. Further studies are needed, but the results obtained with this new three-dimensional bioreactor are promising, and its potential is attractive.

ALEX (artificial liver for extracorporeal xenoassistance): a new bioreactor containing a porcine autologous biomatrix as hepatocyte support. Preliminary results in an ex vivo experimental model

Long-term maintenance of viability and expression of differentiated hepatocyte function is crucial for bioartificial liver support. We developed a new bioreactor design (ALEX), associated with a new extracellular autologous hepatocyte biomatrix (Porcine Autologous Biomatrix - PBM) support. To test this new bioreactor, we compared it to a standard BAL (BioArtificial Liver) cartridge in a ex vivo model using human plasma added to bilirubin, ammonium and lidocaine. A pathology study was performed on both bioreactors. The results suggest that ALEX allows a maximal contact between the perfusing plasma and the liver cells and a proper hepatocyte support by a cell-to-matrix attachment. ALEX is a suitable cell support bioreactor, guaranteeing long-term maintenance of the metabolic activity of hepatocytes when compared to a standard BAL cartridge.

SiO(2) entrapment of animal cells: liver-specific metabolic activities in silicaoOverlaid hepatocytes

Rat hepatocytes in a collagen-gel sandwich configuration were exposed to silicon alkoxides in a gas phase, yielding a 0.05 to 0.15 microm porous silica layer on the gel surface. Cell viability was unaffected by the procedure. After 24 h, bilirubin conjugation, ammonia removal, urea synthesis, and diazepam metabolism were unaffected by the procedure. However, both the ammonia removal rate and diazepam metabolism were increased after 48 hr, whereas urea synthesis was unaffected. These data indicate that silica overlay allows efficient metabolic activity of collagen-gel entrapped hepatocytes. The fact that the KM of bilirubin conjugation was unaffected by the presence of the silica membrane suggests that the transport of albumin-bound substrates is not decreased. The enhancement in some metabolic activities found 48 h after the entrapment procedure may be the result of favorable changes in the hepatocyte microenvironment. These characteristics might be useful for the development of organotypical bioartificial liver devices.

Point-of-care testing of cardiac markers: results from an experience in an Emergency Department

AIM

An experimental approach to the use of point-of-care testing for cardiac markers in the Emergency Department (ED) of our Institution has been carried out using two devices (SCS, Dade Behring and Triage Cardiac Panel, Biosite Diagnostics) for the measurement of cardiac markers.

RESULTS

(1) From the analytical point of view, a fundamental tool for an efficient management of patients was the agreement between results from point-of-care testing and from the instruments located in STAT lab and/or central laboratory: in about 5% of patients, a lack of comparability of data, resulted in an inappropriate admission of patients (medical vs. intensive care unit). (2) The actual total turnaround time (TAT) in the management of samples sent to STAT lab was estimated to be equal to 82.5 min (50th percentile). (3) In the same organizational setting, the use of a point-of-care device produced a turnaround time equal to 17 min (50th percentile). (4) The reduction in turnaround time resulted in a faster discharge for five patients who had normal ECG findings and cardiac marker values, the Delta time (POCT-STAT lab) ranging from -10 to -70 min.

CONCLUSIONS

The point-of-care option evaluated also in relation to personnel issues for staff working in the ED, brought some interesting questions about the characteristics of POCT devices (easy to use 100%, safety for operator 91%) and the obtained results (quantitative and correlated to STAT lab, 91%), as well as the need of other options such as the implementation of rapid tube sample delivery.

Tissue factor pathway inhibitor release induced by defibrotide and heparins

We evaluated the release of tissue factor pathway inhibitor (TFPI) induced by defibrotide (DF), a single-stranded, negatively charged polydeoxyribonucleotide extracted from mammalian organ. Ten normal volunteers were injected with an intravenous bolus of 400 mg DF and 2,000 IU unfractionated heparin (UFH). In addition, three volunteers were also injected with an intravenous bolus of 2,000 anti-Xa U of two low-molecular-weight heparins (LMWHs), enoxaparin and nadroparin. UFH caused a 4-fold increase in plasma TFPI at 5 minutes, with a decrease that was parallel to the heparin level measured by the anti-Xa assay. However, at 80 minutes, although the plasma anti-Xa activity of UFH was almost undetectable, the level of TFPI remained 2-fold baseline. DF induced an increase of TFPI that was 2-fold higher than the baseline level, with a steady state achieved between 5 and 20 minutes. At 40 minutes, the TFPI levels returned to basal level. This pattern was not coincident with the clearance of DF and at 40 minutes, the concentration of DF was still one third of the levels at 5 minutes (25.4 +/- 4.04 microg/mL). Both of the LMWHs induced a similar TFPI peak level at 5 minutes (1.5-fold increase) and at 40 minutes the TFPI levels returned to the initial levels. At 5 minutes, both LMWHs showed a higher plasma anti-Xa activity than UFH, which was detectable even at 80 minutes. The current study demonstrated that one of the mechanisms of the antithrombotic activity of DF is mediated via TFPI. Furthermore, the release of TFPI by heparin is mediated by non-antithrombin III binding fragments. Thus, polyanionic electrolytes are capable of releasing TFPI irrespective of their antithrombin III effect.

Comparison of pig, human and rat hepatocytes as a source of liver specific metabolic functions in culture systems--implications for use in bioartificial liver devices

The limited availability of human hepatocytes results in the use of animal cells in most bioartificial liver support devices. In the present work, clinically relevant liver specific metabolic activities were compared in rat, pig and human hepatocytes cultured on liver-derived biomatrix to optimize the expression of differentiated functions. Pig hepatocytes showed higher rates of diazepam metabolism (2.549+/-0.821 microg/h/million cells vs. 0.474+/-0.079 microg/h/million cells rats, p<0.005, and vs. 0.704+/-0.171 microg/h/million cells in man, p<0.005) and of bilirubin conjugation (21.60116+/-8.433237 micromoles/l/24 h vs. 6.786809+/-2.983758 in man, p<0.001 and vs. 9.956538+/-1.781016 micromoles/l/24 h in rats, p<0.005). Urea synthesis was similar in pig and in human hepatocytes (150+/-46.3 vs. 144.8+/-21.46 nmoles/h/million cells) and it was lower in rats (84.38+/-35.2; p<0.001 vs. man, p<0.02 vs. pig). High liver specific metabolic activities in cultured pig hepatocytes further support their use as a substitue for human cells in bioartificial liver devices.