[Quantitation of human immunodeficiency virus type 1 RNA by ultrasensitive method in the analysis of samples with low viral load].

With the introduction of combination therapy to the patients with Human Immunodeficiency Virus Type 1(HIV-1) infection, HIV-1 RNA levels in plasma have been reduced, frequently to less than limit of quantitation(400 copies/ml). To achieve enhanced sensitivity, a modified specimen preparation procedure that allows the quantitation of plasma HIV-1 RNA levels as low as 50 copies/ml was developed. Of 67 samples with less than 400 copies/ml of HIV-1 RNA by standard method, 39(58.2%) were not detected by the "ultrasensitive" method. Among 5 samples obtained from patients who were treated with 2 nucleoside reverse transcriptase inhibitors, 4 samples still had detectable copies of HIV-1 RNA. Those suggest that the ultrasensitive assay for HIV-1 RNA has advantage for clinical practice.

[Pulmonary thromboembolism accompanied by abnormal plasminogen].

A 38-year-old man was admitted to our hospital because of sudden chest pain and bloody sputum. Lung perfusion scintigraphy disclosed segmental defects in both lungs. An enhanced thin-section computed tomographic scan of the chest showed a low-density area in the right main pulmonary artery. These findings yielded a diagnosis of pulmonary thromboembolism. Serum plasminogen activity was low, not only in the patient but in his elder brother and daughter. Gene analysis revealed a point mutation at exon 15 of the plasminogen gene, suggesting abnormal plasminogen. Abnormal plasminogen is more prevalent in Japan than in the USA or Europe, and is usually asymptomatic. Thromboembolism in patients with abnormal plasminogen is very rare. Further studies are needed to elucidate the relationship between plasminogen abnormalities and pulmonary thromboembolism.

A novel mutation Gly 1672-->Arg in type 2A and a homozygous mutation in type 2B von Willebrand disease.

Genetic materials from 16 unrelated Japanese patients with von Willebrand disease (vWD) were analyzed for mutations. Exon 28 of the von Willebrand factor (vWF) gene, where point mutations have been found most frequent, was screened by various restriction-enzyme analyses. Six patients were observed to have abnormal restriction patterns. By sequence analyses of the polymerase chain-reaction products, we identified a homozygous R1308C missense mutation in a patient with type 2B vWD; R1597W, R1597Q, G1609R and G1672R missense mutations in five patients with type 2A; and a G1659ter nonsense mutation in a patient with type 3 vWD. The G1672R was a novel missense mutation of the carboxyl-terminal end of the A2 domain. In addition, we detected an A/C polymorphism at nucleotide 4915 with HaeIII. There was no particular linkage disequilibrium of the A/C polymorphism, either with the G/A polymorphism at nucleotide 4391 detected with Hphl or with the C/T at 4891 detected with BstEII.

[Fluctuations of tissue-type plasminogen activator.plasminogen activator inhibitor-1 complex in patients with DIC].

Plasma levels of tissue-type plasminogen activator antigen (t-PA:Ag), plasminogen activator inhibitor-1 antigen (PAI-1:Ag), the active form of PAI-1 (active PAI) and t-PA.PAI-1 complex (PAI-C) were analyzed in 7 patients with disseminated intravascular coagulation (DIC) syndrome. The levels of t-PA:Ag and PAI-C decreased after amelioration of DIC in 6 patients whose underlying disease improved, but their PAI-1:Ag and active PAI showed various fluctuations. The levels of t-PA:Ag and PAI-C showed a good correlation of r = 0.885. The levels of t-PA:Ag or PAI-C showed an inversed correlation with platelet counts, and correlations with the levels of plasmin.alpha 2PI complex, D dimer and E fragments of FDP. It was considered that plasma levels of PAI-C reflected levels of t-PA released from the endothelial cells, which was related to acceleration of fibrinolysis in DIC patients with improved underlying disease. On the other hand, these levels remained high in a patient whose underlying disease did not improve after recovering from DIC. It was considered that the stimulation of endothelial cells by cancer cells continued to exert an effect.