Role of plasminogen activator inhibitor-1 in promoting fibrin deposition in rabbits infused with ancrod or thrombin

The role of defective fibrinolysis caused by elevated activity of plasminogen activator inhibitor-1 (PAI-1) in promoting fibrin deposition in vivo has not been well established. The present study compared the efficacy of thrombin or ancrod, a venom-derived enzyme that clots fibrinogen, to induce fibrin formation in rabbits with elevated PAI-1 levels. One set of male New Zealand rabbits received intravenous endotoxin to increase endogenous PAI-1 activity followed by a 1-hour infusion of ancrod or thrombin; another set of normal rabbits received intravenous human recombinant PAI-1 (rPAI-1) during an infusion of ancrod or thrombin. Thirty minutes after the end of the infusion, renal fibrin deposition was assessed by histopathology. Animals receiving endotoxin, rPAI-1, ancrod, or thrombin alone did not develop renal thrombi. All endotoxin-treated rabbits developed fibrin deposition when infused with ancrod (n = 4) or thrombin (n = 6). Fibrin deposition occurred in 7 of 7 rabbits receiving both rPAI-1 and ancrod and in only 1 of 6 receiving rPAI-1 and thrombin (P < .01). In vitro, thrombin but not ancrod was inactivated by normal rabbit plasma and by purified antithrombin III or thrombomodulin. The data indicate that elevated levels of PAI-1 promote fibrin deposition in rabbits infused with ancrod but not with thrombin. In endotoxin-treated rabbits, fibrin deposition that occurs with thrombin infusion may be caused by decreased inhibition of procoagulant activity and not increased PAI-1 activity.     

Identification of T lymphocytes in human mixed hemopoietic colonies

The addition of a T-cell growth-promoting medium (PHA-TCM) to culture conditions that support growth of multi-lineage hemopoietic colonies enhances the proliferation of cells with lymphoid morphology within these colonies. These cells were identified as T lymphocytes by their ability to form rosettes with SRBC and their reaction with monoclonal antibodies (OKT3, OKT4) directed against T-cell-specific surface components. They continue to proliferate extensively under the influence of PHA-TCM after transfer of mixed colonies into liquid suspension culture. Supportive evidence for a common progenitor of myeloid and lymphoid cells within single mixed colonies is provided by Y-chromatin body analysis of E-rosette positive and negative cells in colonies grown in cocultures of male and female bone marrow cells.     

Efficacy of the Za self-expandable metal stent for palliation of malignant biliary obstruction

BACKGROUND: The efficacy and safety of the uncoated self-expandable Za metal stent for palliation of malignant distal biliary obstruction was prospectively analyzed. METHODS: Twenty-one patients with unresectable malignant tumors involving mid to distal common bile duct who presented with obstructive jaundice underwent endoscopic implantation of an uncoated self-expandable metal stent. Technical success with stent placement, adverse events, patient survival, duration of stent patency, and device performance were analyzed. RESULTS: Endoscopic biliary stenting was successful in all patients. No adverse events were encountered. The mean follow-up period of the 21 patients was 128 days (range, 3-263): 14 died of progressive disease at mean of 81 days (range, 3-210), 3 remain alive (at days 239, 250, and 263), and 4 were lost to follow-up (at days 90, 91, 92, and 116). The mean duration of stent patency was 249 days. Tumor ingrowth was observed in one patient (5%). Minor technical problems were encountered in 3 patients: 1 proximal deployment, 1 distal deployment, and difficulty associated with the delivery system in 1. CONCLUSIONS: The Za-metal stent provided effective palliation for patients with inoperable malignant biliary tumors. Although minor technical problems were encountered with stent deployment, the overall stent patency, efficacy, and safety profile appear satisfactory.     

Clinically significant differences between point-of-care analysers and a standard analyser for monitoring the International Normalized Ratio in oral anticoagulant therapy: a multi-instrument evaluation in a hospital outpatient setting.

The increasing number of patients requiring oral anticoagulant therapy has lead to an expansion in the use of point-of-care test (POCT) analysers for measuring the International Normalized Ratio (INR) for monitoring purposes. Availability of new technology inevitably leads to comparisons with standard methodologies, and studies to date have reached varying conclusions about the comparability of POCT INRs with conventional testing. We compared the performance of five POCT instruments (Hemochron Junior Signature, ProTime, CoaguChek S, INRatio and TAS) against Innovin thromboplastin on a Sysmex CA1500 automated analyser. The Hemochron Junior Signature, ProTime and CoaguChek S demonstrated strong correlation with the laboratory method (R2 > 0.94). These three analysers demonstrated higher percentages of paired results within 0.5 INR units (81.5, 92.0 and 74.0%, respectively); the INRatio and TAS demonstrated 54.2 and 62.2%, respectively. Within INR ranges of up to 2.0, 2.1-3.0, 3.1-4.0 and above 4.0, none of the POCT analysers demonstrated significant agreement with the standard method in every range. All POCT instruments showed a degree of bias and greater variation from the standard method at INR values above 3.0. These data indicate the potential for POCT analysers to generate INR values sufficiently different from conventional methods that they may impact on clinical decision-making.     

GSTM1 null polymorphism at the glutathione S-transferase M1 locus: phenotype and genotype studies in patients with primary biliary cirrhosis.

Studies were carried out to test the hypothesis that the GSTM1 null phenotype at the mu (mu) class glutathione S-transferase 1 locus is associated with an increased predisposition to primary biliary cirrhosis. Starch gel electrophoresis was used to compare the prevalence of GSTM1 null phenotype 0 in patients with end stage primary biliary cirrhosis and a group of controls without evidence of liver disease. The prevalence of GSTM1 null phenotype in the primary biliary cirrhosis and control groups was similar; 39% and 45% respectively. In the primary biliary cirrhosis group all subjects were of the common GSTM1 0, GSTM1 A, GSTM1 B or GSTM1 A, B phenotypes while in the controls, one subject showed an isoform with an anodal mobility compatible with it being a product of the putative GSTM1*3 allele. As the GSTM1 phenotype might be changed by the disease process, the polymerase chain reaction was used to amplify the exon 4-exon 5 region of GSTM1 and show that in 13 control subjects and 11 patients with primary biliary cirrhosis, GSTM1 positive and negative genotypes were associated with corresponding GSTM1 expressing and non-expressing phenotypes respectively. The control subject with GSTM1 3 phenotype showed a positive genotype.     

Reversal of granulocyte adherence to nylon fibers using local anesthetic agents: possible application to filtration leukapheresis

The effects of the cationic anesthetic agents tetracaine and lidocaine on granulocyte function, morphology, and adherence to nylon fibers were studied in an attempt to improve current methods of granulocyte collection by filtration leukapheresis (FL). When dissolved in acid- citrate-dextrose (ACD) plasma, these drugs significantly increased granulocyte elution from the fibers in a dose-related fashion. Granulocytes exposed to tetracaine and lidocaine remained more than 95% viable, retained normal bactericidal capacity after the drugs were washed from the cells, and had preserved membrane integrity, as evidenced by the normal ultrastructural appearance of tetracaine- exposed cells and an absence of leakage of lysozyme or lactic dehydrogenase. Granulocytes eluted with the anesthetic agents were rounded in shape with a reduction in the number of filopodial cytoplasmic projections and a relative absence of cytoplasmic vacuolization when compared to granulocytes eluted with ACD plasma alone. Dose-related inhibition of phagocytosis and adherence, which was largely reversible after washing the granulocytes, was noted. Greater than 95% of the lidocaine could be removed from the eluate with a single centrifugation and resuspension, indicating that granulocytes prepared by FL with anesthetic-enhanced elution could be potentially transfusable.     

RFLPs of the phenylalanine hydroxylase gene in the Italian population

Summary Different mutations of the phenylalanine hydroxylase (PAH) gene leading to phenylketonuria (PKU) have been described associated with specific haplotypes in several European countries. In order to investigate the distribution of DNA haplotypes in Italy, restriction fragment length polymorphism (RFLP) analysis of the PAH gene was performed in nine Italian PKU patients from eight unrelated families, and in the available relatives. The analysis of eight polymorphic sites revealed haplotypes 1 and 6 in association with PKU. This pattern appears to differ from those reported for other European populations.The majority of the 14 PKU subjects studied showed compound heterozygosity for different haplotypes, as observed for other European series.RFLP analysis at the PAH locus allowed us to offer the possibility of prenatal diagnosis to six of the studied families. One prenatal diagnosis was performed and a normal fetus was diagnosed.     

Endoscopic biliary therapy using the combined percutaneous and endoscopic technique

Between September 1985 and December 1987, 74 patients underwent attempted endoscopic biliary therapy using a combined percutaneous transhepatic and endoscopic transpapillary approach (combined procedure). All patients had had failed endoscopy-alone procedures and had contraindications to surgery. The indication was palliation of malignant biliary obstruction in 66 cases (41 common bile duct, 25 hilar), assistance with sphincterotomy for the removal of common bile duct stones in 6 cases, and management of benign biliary stenosis in 2 cases. The initial procedure was percutaneous transhepatic access to the biliary tree, which was successful in all but 1 case (99%). The bile duct was drained externally for an average of 3.4 days before the combined procedure. One patient died during this period from hemorrhage associated with liver puncture. Combined procedure was performed in 72 cases and was successful in 60 [53 malignant stricture (53/66 = 80%), five common duct stone (5/6 = 83%), two benign stricture (2/2 = 100%)]. Procedure-related morbidity and mortality, respectively, were 12.5% and 0% for benign disease and 36% and 3% for malignant disease. The total (initial endoscopy included) morbidity and 30-day mortality were 33% and 0%, respectively, for benign disease and 62% and 27% for malignant disease. Subsequently, stent change has been required on 16 occasions, with endoscopy-only successful in 13 (81%) and repeat combined procedure being required in three (19%). The combined procedure improves the ability of endoscopy to offer nonsurgical therapy to poor risk patients with both malignant and benign biliary disease but is associated with significant morbidity and disease-related mortality.     

Homozygous and compound heterozygous mutations in the ATP6V1B1 gene in patients with renal tubular acidosis and sensorineural hearing loss

Mohebbi N, Vargas‐Poussou R, Hegemann SCA, Schuknecht B, Kistler AD, Wüthrich RP, Wagner CA. Homozygous and compound heterozygous mutations in the ATP6V1B1 gene in patients with renal tubular acidosis and sensorineural hearing loss. Distal renal tubular acidosis (dRTA) is characterized by the inability to excrete acid in the renal collecting ducts resulting in inappropriately alkaline urine and hyperchloremic (normal anion gap) metabolic acidosis in the context of a normal (or near‐normal) glomerular filtration rate. Inborn dRTA can be due to autosomal dominant or recessive gene defects. Clinical symptoms vary from mild acidosis, incidental detection of kidney stones or renal tract calcification to severe findings such as failure to thrive, severe metabolic acidosis, and nephrocalcinosis. The majority of patients with recessive dRTA present with sensorineural hearing loss (SNHL). Few cases with abnormal widening of the vestibular aqueduct have been described with dRTA. Mutations in three different genes have been identified, namely SLC4A1, ATP6V1B1, and ATP6V0A4. Patients with mutations in the ATP6V1B1 proton pump subunit develop dRTA and in most of the cases sensorineural hearing loss early in childhood. We present two patients from two different and non‐consanguineous families with dRTA and SNHL. Direct sequencing of the ATP6V1B1 gene revealed that one patient harbors two homozygous mutations and the other one is a compound heterozygous. To our knowledge, this is the first case in the literature describing homozygosity in the same dRTA gene on both alleles.