A novel STK11 germline mutation in two siblings with Peutz-Jeghers syndrome complicated by primary gastric cancer

Patients with Peutz-Jeghers syndrome (PJS) are known to be at risk of gastric cancer (GC), and the STK11 gene is a susceptibility gene for PJS. However, as no cases of PJS with GC in which a STK11 germline mutation has been identified have ever been reported and other susceptibility genes have also been suggested to be involved in PJS, the relation between STK11 germline mutations and GC in PJS is still unknown. In this study, we used sequencing analysis to investigate the STK11, CDH1, and TP53 loci for a germline mutation in two siblings with PJS with primary GC. A novel type of the STK11 germline mutation, c.890delG, encoding a truncated protein (p.Arg297fsX38) was identified, but no germline mutations of the CDH1 and TP53 genes were detected. No inactivation of the wild-type allele by somatic mutation or chromosomal deletion or hypermethylation at the 5'-CpG site of STK11 was detected in the GC. This is the first report of a STK11 germline mutation in a PJS patient with GC and should contribute to establishing correlations between the STK11 germline mutations and GC in PJS patients.

The region from phenylalanine-17 to phenylalanine-28 of a yeast mitochondrial ATPase inhibitor is essential for its ATPase inhibitory activity

Mitochondrial ATP synthase (F(1)F(o)-ATPase) is regulated by an intrinsic ATPase inhibitor protein. In the present study, we investigated the structure-function relationship of the yeast ATPase inhibitor by amino acid replacement. A total of 22 mutants were isolated and characterized. Five mutants (F17S, R20G, R22G, E25A, and F28S) were entirely inactive, indicating that the residues, Phe17, Arg20, Arg22, Glu25, and Phe28, are essential for the ATPase inhibitory activity of the protein. The activity of 7 mutants (A23G, R30G, R32G, Q36G, L37G, L40S, and L44G) decreased, indicating that the residues, Ala23, Arg30, Arg32, Gln36, Leu37, Leu40, and Leu44, are also involved in the activity. Three mutants, V29G, K34Q, and K41Q, retained normal activity at pH 6.5, but were less active at pH 7.2, indicating that the residues, Val29, Lys34, and Lys41, are required for the protein's action at higher pH. The effects of 6 mutants (D26A, E35V, H39N, H39R, K46Q, and K49Q) were slight or undetectable, and the residues Asp26, Glu35, His39, Lys46, and Lys49 thus appear to be dispensable. The mutant E21A retained normal ATPase inhibitory activity but lacked pH-sensitivity. Competition experiments suggested that the 5 inactivated mutants (F17S, R20G, R22G, E25A, and F28S) could still bind to the inhibitory site on F(1)F(o)-ATPase. These results show that the region from the position 17 to 28 of the yeast inhibitor is the most important for its activity and is required for the inhibition of F(1), rather than binding to the enzyme.

Nucleotide sequence of cDNA coding the mitochondrial precursor protein of the ATPase inhibitor from humans

Mitochondrial ATP synthase (F1Fo-ATPase) is regulated by an intrinsic ATPase inhibitor protein. In the present study, cDNA coding the human homolog of the inhibitor protein was isolated and sequenced. The deduced protein sequence shows that the protein was composed of 106 amino acids and had a molecular weight of 12248. The structural features of the protein show that the cDNA isolated in this study codes the human ATPase inhibitor.

Possible cause of unnatural mass death of wild birds in a pond in Nishinomiya, Japan: sudden appearance of toxic cyanobacteria

During the summer of 1995, about 20 spot-billed ducks died unnaturally in a pond (Shin-ike) in Nishinomiya, Hyogo Prefecture, Japan. The suspected cause was the sudden appearance of toxic freshwater bloom of cyanobacteria. However, no birds died in a nearby pond (Oo-ike) in which the cyanobacteria was also present. Morphological observation of these cyanobacteria by microscope revealed that they were almost unialgal and were both Microcystis aeruginosa. The lyophilized algal cell powder from Shin-ike contained large amounts of microcystins which showed acute toxicity for mouse, while that from Oo-ike had only a very small amount of microcystin-RR which did not show acute toxicity. Autopsy of one of the birds revealed that the liver was necrotic and severely jaundiced with a dark green color, suggesting the toxicity of the microcystins. These results point to the cause of the unnatural death of spot-billed ducks in Shin-ike as being the sudden appearance of toxic Microcystis aeruginosa. This was due to eutrophication of the pond, following the influx of untreated sewage related to damage from the Great Hanshinn Earthquake of January 1995. This is the first experimental report of toxic cyanobacteria being implicated in the mass death of wild birds in Japan.

A catalytic antibody isomerizing a delta 5-3-cétostéroïde

Antibodies were raised against 3-fluoro-4-aza-estradiol-17-hemisuccinate to elicit abzymes capable of isomerizing delta 5-3-ketosteroids. The hapten was designed to present a planar A ring showing some analogy with the intermediate dienol and a polarity capable of inducing catalytic groups. Antibodies binding the hapten tightly were cloned and purified from either ascites or hybridoma supernatants. Catalytic activity was tested with androst-5-ene-3,17-dione. Among the five different monoclonal antibodies binding the hapten, one proved to enhance significantly the substrate isomerization rate (kcat/kuncat = 830). Initial rates followed Michaelis kinetics and the activity was competitively inhibited by the hapten.

[A case of pulmonary nocardiosis diagnosed by percutaneous aspiration]

A 71-year-old man complained of mild dyspnea, and his chest X-ray showed a cavitating lesion accompanied by infiltrative changes in the right middle lobe. Percutaneous aspiration revealed numerous gram-positive and acid-fast branching rods. Morphological examination and biochemical tests of the colonies confirmed the diagnosis of pulmonary nocardiosis caused by nocardia asteroides. The patient was treated successfully with sulfamethoxazole-trimethoprim. It has been reported that approximately half of the patients with pulmonary nocardiosis have immunodeficiency, but our patient had no underlying disease. This disease has no characteristic clinical features, so diagnosis is difficult. As nocardia may involve the central nervous system leading to a poor prognosis, early diagnosis and prompt treatment are required to improve survival.

[A case of hypereosinophilic syndrome associated with eosinophilic endocarditis]

A 66-year-old woman, who had had bronchial asthma, was admitted to our hospital because she suffered from fever, productive cough, wheezing, dyspnea, and chest pressure sensation. Her chest X-ray showed migrating infiltration and marked cardiomegaly. Her ECG at the admission revealed abnormal Q wave and T wave inversion, though that of 3 years before had been almost normal. Hematology showed leukocytosis and eosinophilia of 8,000/mm3 without abnormal cells. All immunological tests were negative and the specific cause of the eosinophilia was unknown. 2 weeks after admission, she complained of severe chest pain suddenly and her ECG showed ST elevation on V1-4 and serum CPK level was elevated to 290 IU/l. By the thrombolytic agent and anticoagulant therapy, her symptom was lightened immediately. 2 months later, we made her cardiac catheterization and myocardial biopsy. Her LVG showed a small aneurysm of the apex, though her CAG was normal finding. The biopsy revealed moderate fibrosis and cellular infiltration including a few eosinophils. We thought that eosinophilic endocarditis had existed first, and secondary embolism continued led to the small infarction. The hypereosinophilia was spontaneously normalized 2 months after admission, but the patient complained of myalgia and sensory disturbance of extremities. The biopsy of quadriceps muscle could prove neither infiltration of eosinophils nor vasculitis. But we diagnosed mononeuritis multiplex due to hypereosinophilia. Judging from various symptoms and laboratory findings, this case was included to the hypereosinophilic syndrome. We also thought allergic granulomatosis and angitis as one of the differential diagnoses, but histologically vasculitis was not proved. In this case, eosinophilia was disappeared without using corticosteroids.(ABSTRACT TRUNCATED AT 250 WORDS)

Spontaneous regression of pulmonary metastasis from renal pelvic cancer

A case of spontaneous regression of multiple pulmonary metastases of transitional cell carcinoma is reported. Spontaneous regression of metastatic pulmonary lesions seldom occurs in transitional cell cancer, and only 3 such cases have been reported in the literature. A 42-year-old male with multiple pulmonary metastases which had regressed spontaneously for a significant period of time is herein reported. The lesions were shown to be transitional cell carcinoma, originating from the left renal pelvis. The serial immunological examinations suggest that the phenomenon might be attributed to the augmented immune response of the patient.