[Prolonged anticoagulation following chlorophacinone poisoning]

In 1985 and 1986 the Swiss Toxicologic Information Center registered 152 cases of rodenticide poisoning. Among those substances chlorophacinone, an indanedione derivative, has a prolonged antivitamin K effect. We report here the case of an eighteen-year-old female hospitalized 3 days after deliberately ingesting some 100 mg chlorophacinone. Her Quick time at admission was less than 10% (Prothrombin time 79 sec., normal control 12 sec.). Under high dose vitamin K therapy the Quick was rapidly corrected but fell again on each vitamin K withdrawal. In a search for a relation between the variations of prothrombin time and chlorophacinone plasma levels, these were assessed by HPLC. Prothrombin time (and vitamin K dependent factors VII and X) finally normalized only 7 weeks after chlorophacinone ingestion. Clinical condition remained satisfactory throughout and other biological parameters unaffected. This case emphasizes the need for prolonged clinical and laboratory follow-up for rodenticide intoxications and for vitamin K administration for several weeks.

[Acquired hemophilia. Apropos of a case report with a fatal course]

We report the case of an 86-year-old female with an unremarkable past history who suddenly developed severe and generalized bleeding. Laboratory work-up revealed prolonged aPTT, a factor VIII level of 7% and the presence of a factor VIII inhibitor. In spite of whole blood, factor VIII concentrates and immunoglobulin administration, the patient died of multiple hemorrhages on the third day after admission. At autopsy no causal or associated pathology could be found. Chromatographic separation of plasma immunoglobulins showed that the anti-factor VIII activity was associated with the patient's IgG. This inhibition was partially corrected in vitro by injectable immunoglobulin preparation. The case report stresses the discrepancy between the measured levels of inhibitor and the severity of the bleeding; our in vitro results may shed light on the mode of action of intravenous immunoglobulins.

Determination of S-carboxymethylcysteine in serum by reversed-phase ion-pair liquid chromatography with column switching following pre-column derivatization with o-phthalaldehyde

A method is described for the determination of S-(carboxymethyl)-L-cysteine in serum. After addition of S-(carboxyethyl)-L-cysteine as internal standard, both compounds are extracted into methanol, converted into fluorescent derivatives with o-phthalaldehyde and quantitatively determined by reversed-phase high-performance liquid chromatography. Chromatography of unwanted amino acid derivatives is avoided by column switching, thereby shortening analysis time and increasing column lifetime. The technique was applied in a study of the bioavailability of S-(carboxymethyl)-L-cysteine after oral administration to humans. The concentration-response curve was linear from 2 to 16 micrograms/ml; mean serum concentrations are reported.

Comparison between a low molecular weight and standard heparin for anticoagulation during extracorporeal CO2 removal in the dog

Anticoagulant properties towards an artificial surface of a chemically depolymerized low molecular weight heparin (LMWH) have been compared to those of a standard heparin (SH). The experimental model consisted in a seven hours extracorporeal veno-venous bypass for CO2 removal (EC-CO2R) using a membrane lung. Four animals received 150 anti-FXa U/kg followed by 40 anti-FXa U/kg/h of LMWH or 300 IU/kg followed by 100 IU/kg/h of SH. Mean Factor Xa inhibition was 49% in LMWH group and 28.5% in SH group. Mean Factor IIa inhibition was 31% and 49% respectively. After three hours of bypass fibrin deposition occurred in the reservoir in three out of four dogs receiving LMWH while none was observed under SH. No statistically significant difference between the two groups was found for any of the coagulation parameters tested (fibrinogen, factor V, antithrombin III, plasminogen, alpha 2-antiplasmin, platelet counts). At the end of bypass 5000 U protamine abolished both anti-FXa and anti-FIIa activities in the SH group but failed to neutralize more than half of the anti-FXa activity in the LMWH group. These results suggest that high anti-FIIa activities are required to prevent fibrin formation induced by artificial surfaces and that equivalent amounts of anti-FXa activities are ineffective for this purpose. In addition the use of LMWH may raise problems when emergency neutralization procedures are required.

[Bernard-Soulier syndrome in a Swiss family]

We report the case of a 38-year-old woman with hemorrhagic diathesis. Since early childhood she has suffered from epistaxis, gingival bleeding, ecchymoses and, since puberty, very frequent menorrhagia. Prolongation of bleeding time and thrombocytopenia (100,000 platelets/microliter) with giant platelets were observed. Since idiopathic thrombopenic purpura was suspected, splenectomy was performed. Neither this nor steroid treatment caused any improvement. The patient was able to give birth to an unaffected child, but delivery was followed by a major hemorrhage. In 1986, hysterectomy was considered because of frequent menorrhagia and, therefore, the patient's hemostasis was reinvestigated. The aforementioned abnormalities were confirmed and complementary examinations by electron microscope revealed giant platelets without granular abnormalities. While von Willebrand factor was normal, ristocetin agglutination was defective and analysis of platelet membrane glycoproteins showed absence of glycoprotein Ib. - These observations prompted the diagnosis of Bernard-Soulier syndrome. The study of the family demonstrated that 6 family members were heterozygote. This is believed to be the first large Bernard-Soulier family reported in Switzerland.

[Femoral artery thrombosis associated with heparin-induced thrombopenia]

We report a case of acute thrombosis of the common femoral artery which occurred on the tenth day of postoperative prophylactic heparin therapy. Platelet count was 14,000/mm3 at the time of the acute event. Cessation of heparin administration resulted in progressive normalization of the platelet count. Iliofemoral thrombectomy, followed by popliteal thromboembolectomy, allowed successful recanalization of the occluded arteries, after failure of local thrombolysis with low-dose streptokinase. The pathogenesis, diagnosis and treatment of heparin-induced thrombocytopenia associated with thromboembolic complications are discussed.

Evidence for an HLA-linked resistance gene in Buerger's disease

The incidence of Thromboangiitis Obliterans in brothers and the high prevalence in some ethnic groups have led us to investigate the histocompatibility HLA-A, B and DR antigens of 46 Buerger's disease patients. The main result indicates a marked decreased freqeuncy of the B12 antigen: 2.2% vs 28% in controls. Our study suggests that Buerger's disease is, on the basis of HLA antigens, a distinct immunogenetic entity and not a particular form of arteriosclerosis. Moreover, this disorder may represent a clue to the existence of resistance genes linked to HLA.

Increased frequency of HLA--DRw2 and DRw3 in multiple sclerosis

Previous studies of multiple sclerosis patients showed the existence of a positive association between multiple sclerosis and HLA--A3 and --B7, as well as a negative association with B12. These observations have been confirmed. In addition, a more marked association has been observed with two recently identified B-cell antigens, DRw2 and DRw3, closely related to the HLA--D locus. The presence of cold lymphocytotoxic antibodies was found to bear no relationship with those two specificities. These results suggest that two genes of the HLA--DR region may play a role in the pathogenesis of multiple sclerosis.

A screening program for anti-DR typing reagents

A total of 694 sera have been tested in a screening program aimed at identifying monospecific reagents for HLA--DR typing. All sera were first tested on a panel of enriched B and T cells without absorption on platelets. Only sera reacting more frequently on B than on T lymphocytes were absorbed on platelets and retested on the panel. This procedure saved a considerable amount of platelets and proved to be reasonably efficient. One-hundred-and-fifty sera were found to contain an anti-B cell antibody. Significantly less frequent B cell reactivity was found when HLA--A, --B, --C antibodies could not be detected. Twenty-five sera were demonstrated to be specific for well-defined DR antigens.

HLA and glioma

HLA typing of 80 glioma patients was determined and the antigen frequencies were compared with 176 normal controls. Increased phenotypic frequencies of Bw35 and DRw1 were observed, but when P values were corrected by the number of antigens tested (35), the results were no longer significant.

[HL-A D antigens from B-lymphocytes and susceptibility to certain diseases]

The discovery of many associations between HLA and human diseases has emphasized the biologic importance of the main histocompatibility system in man. The recent findings from specific immune response genes (Ir locus) mapping within the H2 region of the mouse have led to systematic study of the similar D locus mapping within the HLA region in man. In this study the frequency of a number of HLA-D antigens has been determined in normal individuals and in patients with four diseases selected in view of their genetic background: juvenile diabetes, multiple sclerosis, grass pollinosis and acute leukemia. In each a significant association has been found with a specific HLA-D antigen: DW3 in juvenile diabetes and grass pollinosis, DW2 in multiple sclerosis, and DW7 in acute lymphoblastic leukemia.