Shiro Tsujimoto

Role of bacterial capsule in local and systemic inflammatory responses of mice during pulmonary infection with Klebsiella pneumoniae.

The role of bacterial capsule in inflammatory responses in experimentally induced pneumonia caused by Klebsiella pneumoniae was evaluated by comparing the host immunological responses in mice infected with capsulate strain DT-S and non-capsulate mutant strain DT-X. Anaesthetised ICR mice were infected intranasally with inocula of strain DT-S or DT-X. Mice infected with strain DT-X survived significantly longer than those inoculated with strain DT-S. Viable bacterial counts in lungs and blood increased rapidly in mice infected with strain DT-S, in contrast to the gradual decrease in their density in lungs and intermittent bacteraemia in mice infected with strain DT-X. The number of broncho-alveolar lavage (BAL) cells in mice infected with strain DT-X at 24 h after inoculation was significantly higher than in those infected with strain DT-S. In the early stages of infection, the levels of tumour necrosis factor-a and interleukin-6 in BAL fluid of mice infected with strain DT-X were significantly higher than those of mice infected with strain DT-S. In contrast, in the late stage of infection, the levels of these cytokines in serum of mice infected with strain DT-S were significantly higher than in mice infected with strain DT-X. These results suggest that K. pneumoniae capsule may suppress the host immunological responses,thus allowing the bacteria to grow, causing pneumonia, septicaemia and death.

Induction of interleukin-10 and down-regulation of cytokine production by Klebsiella pneumoniae capsule in mice with pulmonary infection.

The role of the capsule of Klebsiella pneumoniae in inducing cytokine production was investigated by comparing the responses of mice with experimentally induced pneumonia caused by capsulate (strain DT-S) or non-capsulate (mutant strain DT-X) K. pneumoniae. Anaesthetised ICR mice were inoculated intranasally. Whereas all DT-S-infected mice died within 3 days, no deaths were observed in DT-X-infected mice by 14 days after infection. During the early stage of infection, interferon-gamma (IFN-gamma) levels in bronchoalveolar lavage fluid (BALF) of DT-X-infected mice were significantly higher than those in DT-S-infected mice. In contrast, in the late stage of infection, serum levels of granulocyte macrophage-colony stimulating factor (GM-CSF) and IFN-gamma in DT-S-infected mice were significantly higher than those in DT-X-infected mice. Levels of interleukin10 (IL-10) in BALF and serum of DT-S-infected mice were significantly and persistently higher than those of DT-X-infected mice. The IL-10/TNF-alpha (tumour necrosis factor-a) ratios in BALF and serum indicated that higher levels of IL-10 production were induced in mice infected with strain DT-S than in those infected with strain DT-X. The results suggest that the capsule of K. pneumoniae may induce IL-10 production at the site of infection and, thereafter, these high IL-10 levels may serve to down-regulate the expression of pro-inflammatory cytokines.

A case of pulmonary arteritis with stenosis of the main pulmonary arteries with positive myeloperoxidase-antineutrophil cytoplasmic autoantibodies

A 53‐year‐old woman was referred to our hospital with the main symptoms of productive cough, fever and exertional dyspnoea. Chest X‐ray revealed enlargement of the left hilar shadow and cavitary infiltration in the right upper lobe. 99mTechnetium‐macroaggregated albumin (99mTc‐MAA) perfusion scintigram showed complete hypoperfusion through the entire right lung. A pulmonary angiogram revealed stenotic lesions in the right and left main pulmonary arteries. Right cardiac catheterization showed an elevated right ventricular systolic pressure. There was no evidence of systemic arterial lesions nor vasculitis. The patient was positive for myeloperoxidase (MPO)antineutrophil cytoplasmic autoantibodies (ANCA) (168 EU). The Mycobacterium avium complex sputum culture was positive. The pulmonary stenotic lesions were surgically resected. The resected pulmonary arterial lesions were pathologically diagnosed as non‐specific vasculitis. The cavitary lesion disappeared 6 months after the surgery. Two years after the surgery, although the MPO‐ANCA level had decreased to 12 EU, stenosis of the pulmonary arteries reappeared. It is suggested that the patient became positive for MPO‐ANCA in association with the Mycobacterium avium complex infection, and that the presence of MPO‐ANCA may not be related to the development of pulmonary stenosis of the main pulmonary arteries.

Collision carcinoma at the esophagogastric junction.

Atrue collision carcinoma at the esophagogastric junction is rare. In this article, we report colliding double primary cancers of the esophagus and the stomach in a 68-year-old man and discuss this entity. Pathological analysis after total gastrectomy and partial esophagectomy showed the following findings. Areas of squamous differentiation were found on the esophageal side of the tumor and were adjacent to normal mucosa, and areas of glandular differentiation were found to the gastric side of the tumor and adjacent to normal mucosa. These two tumors collided at the esophago-cardiac junction, but there was no intermingling. In one lymph node, an independent non-intermingled metastatic adenocarcinoma and squamous cell carcinoma were observed. The pathological findings of this case satisfy rigorous criteria for collision carcinoma.

A case of intrarenal benign cystic teratoma.

A 6 year-old boy was diagnosed with infected renal cysts that were removed in pieces. Cytological examination of purulent fluid from the cysts during surgery contained a few isolated keratinizing aquamous cells and hair shafts with inflammatory background. Intrarenal cystic teratoma is very rare. Differential diagnosis of intrarenal cysts is paramount, especially in children, to ensure the correct choice of therapy. In our case, we found cytologic examination duning surgery to be useful in dianosis.