The Thermosensitive Lesion in the Replication of the Drug Resistance Factor, Rts1

The DNA of the thermosensitive R factor, Rts1, has been examined by the technique of sedimentation in alkaline sucrose density gradients. Rts1 DNA was found as closed covalent circles in only a few copies per cell in an Escherichia coli host at the permissive temperature. Rts1 DNA appears to be synthesized at the nonpermissive temperature, but was not found as closed covalent circles. However, circular DNA could be recovered upon shift down to the permissive temperature. The large number of plasmid-negative cells which accumulate after prolonged culture at non-permissive temperature may be due to a strong selective pressure favoring the growth of rare R(-) segregants.     

Surgical resection of malignant lymphoma in the right atrium after systemic chemotherapy

A 74-year-old man was referred to us for evaluation of a tumor in the right atrium (RA). Transesophageal echocardiography (TEE) showed an unmovable 50x60 mm mass in the RA. Based on histological findings of subcutaneous tumors in the right abdominal wall, he was diagnosed as malignant lymphoma (ML), and treated with a THP-COP regimen. Upon completion of first THO-COP therapy, TEE showed marked regression of the mass and division into 3 masses, one of which showed marked floating movement with a small stalk. To prevent the risk of embolic events, surgical resection was performed. Resected tumors were necrotic tissues. Serial imaging of cardiac tumor and surgical resection is desirable to decrease the possibility of embolic complication.     

Japanese family with congenital factor VII deficiency

Congenital factor VII (FVII) deficiency is a rare bleeding disorder with autosomal recessive inheritance. The present female patient was diagnosed with congenital FVII deficiency because of low hepaplastin test (HPT), although vitamin K was given. Heterozygous p.A191T mutation was detected in the peripheral blood, and the same mutation was also found in the mother and sister. To the best of our knowledge, this is the fourth reported case of p.A191T mutation of FVII in the literature and the first to be reported in Japan. FVII coagulation activity (FVII:C) in asymptomatic heterozygous carriers is mildly reduced. Therefore, some patients may not be accurately diagnosed with congenital FVII deficiency. In infants with low HPT without vitamin K deficiency, congenital FVII deficiency should be considered.     

Effects of gastric inhibitory polypeptide and glucagon on portal venous and hepatic arterial flow in conscious dogs

Gastric inhibitory polypeptide (GIP) has considerable structural homology with glucagon, which is known to increase liver blood flow. We compared the effects of GIP on portal venous and hepatic arterial flow with those of glucagon in conscious dogs. Injection of GIP significantly increased portal venous flow in a dose-related manner (by 7%, 15%, and 46% at doses of 1, 100, and 500 pmol/kg, respectively). The increase in portal venous flow induced by GIP and glucagon was comparable; however, the increase in portal venous flow after GIP injection reached its peak significantly earlier than that after glucagon injection. Hepatic arterial flow decreased after GIP injection (by 17%, 21%, and 35% at doses of 1, 100, and 500 pmol/kg, respectively), whereas it was not altered by glucagon. Thus, GIP causes significant changes in both portal venous and hepatic arterial flow in conscious dogs. Although structurally related, GIP and glucagon may influence liver blood flow through different mechanisms.Supported by a grant from the Ministry of Education, Japan (No. A-02404052)     

A case of endocapillary proliferative glomerulonephritis with macrophages phagocytosing monoclonal immunoglobulin lambda light chain

Multiple myeloma (MM) is a plasma‐cell neoplasm that can cause renal disorders. Renal lesions in MM can present with a very rare pathological manifestation involving a specific monoclonal immunoglobulin (Ig). We report the case of a 33‐year‐old woman who had edema, fatigue, elevated serum creatinine levels, hypoalbuminemia, and hypercholesterolemia. She had persistent hematuria and proteinuria lasting 3 years. Serum protein electrophoresis showed an M‐spike, and serum immunofixation demonstrated the presence of monoclonal IgG λ. She had proteinuria in the nephrotic range, and a monoclonal λ fragment was present on urine immunofixation. Renal biopsy showed proliferative glomerulonephritis with λ light chain and C3c deposition and inflammatory cell infiltration with CD68. Macrophage lysosomes contained λ light chains, suggesting their partial phagocytosis. She was diagnosed with symptomatic MM and was treated with bortezomib and dexamethasone and an autologous peripheral stem cell transplant conditioned with intravenous melphalan. She achieved a partial response with decreased serum monoclonal protein and improved renal function. This case may be categorized as a monoclonal gammopathy‐associated proliferative glomerulonephritis. The biopsy finding of partially phagocytosed Ig λ light chains by macrophages is very rare; this pathological condition is similar to crystal‐storing histiocytosis.     

Establishment of a leukaemic cell line from a patient with acquisition of chromosomal abnormalities during disease progression in myelodysplastic syndrome

Summary. A cell line designated SKM-1 was newly established from leukaemic cells of a 76-year-old Japanese male patient with monoblastic leukaemia following myelodysplastic syndrome (MDS). The cells were obtained from peripheral blood of the patient when he lost multiple point mutations of ras genes with acquisition of chromosomal abnormalities during disease progression in MDS. The cells grew as a single floating cell, and have been continuously growing with the morphological characteristics of immature monoblasts by serial passages during the past 42 months with a doubling time of about 48 h. By cytochemical analysis. the cloned cells were positive for butyrate esterase, but negative for the Epstein-Barr virus associated nuclear antigen. Phenotypic analysis revealed the expression of myelomonocyte specific antigens such as CD4, CD13, CD33 and HLA-DR. Cells from the primary peripheral blood and those from SO passages of the SKM-1 cell line both possessed no activated ras genes but showed karyotype abnormalities with 46.XY, del(9)(q13;q22), der(17) t(17:?)(p13:?). The SKM-1 cells have two mutations in p53 gene and overexpress the pS3 products. This cell line may contribute to a better understanding of molecular mechanisms in the progression from MDS to myelogenous leukaemia.