Activation of EDTA-resistant gelatinases in malignant human tumors.

Among the many proteases associated with human cancer, seprase or fibroblast activation protein alpha, a type II transmembrane glycoprotein, has two types of EDTA-resistant protease activities: dipeptidyl peptidase and a 170-kDa gelatinase activity. To test if activation of gelatinases associated with seprase could be involved in malignant tumors, we used a mammalian expression system to generate a soluble recombinant seprase (r-seprase). In the presence of putative EDTA-sensitive activators, r-seprase was converted into 70- to 50-kDa shortened forms of seprase (s-seprase), which exhibited a 7-fold increase in gelatinase activity, whereas levels of dipeptidyl peptidase activity remained unchanged. In malignant human tumors, seprase is expressed predominantly in tumor cells as shown by in situ hybridization and immunohistochemistry. Proteins purified from experimental xenografts and malignant tumors using antibody- or lectin-affinity columns in the presence of 5 mmol/L EDTA were assayed for seprase activation in vivo. Seprase expression and activation occur most prevalently in ovarian carcinoma but were also detected in four other malignant tumor types, including adenocarcinoma of the colon and stomach, invasive ductal carcinoma of the breast, and malignant melanoma. Together, these data show that, in malignant tumors, seprase is proteolytically activated to confer its substrate specificity in collagen proteolysis and tumor invasion.

Inhalation of tobramycin in a patient with aspiration pneumonia as a result of medullary stroke.

A 78-year-old man suffered from refractory aspiration pneumonia as a result of a minor medullary stroke. The only neurological symptom observed in this patient was difficulty in swallowing. He was managed with i.v. hyperalimentation with termination of oral intake, including water. However, he still experienced several episodes of aspiration pneumonia. As he was considered to have a bacterial infection because of silent aspiration of colonized oropharyngeal material, inhalation of tobramycin was introduced and successful control of airway infection was attained.

Adult-onset familial pulmonary fibrosis in Japanese brothers.

Two Japanese brothers were diagnosed in their 20s with familial pulmonary fibrosis, the pathological findings of which were consistent with usual interstitial pneumonia (UIP). However, an atypical characteristic was observed in the lungs of these brothers; 2-mm areas of 'honeycomb' were identified throughout the lungs, which is smaller than the generally observed 5-10 mm honeycombing seen in UIP. Fibroblastic foci were demonstrated in the second eldest brother, but not in the eldest, which indicates that the lungs of the eldest brother was in a more advanced stage of fibrosis. Their youngest brother and parents have no clinical evidence of pulmonary fibrosis. All five family members had low values for the diffusion capacity of the lung for carbon monoxide (DLCO), suggesting the presence of an inheritable disease and the existence of different phenotypes. The genomic DNA of the affected brothers was sequenced for the reported surfactant protein C (SP-C) gene mutations in patients with familial pulmonary fibrosis, but none was documented. It is necessary to clarify the presence of novel gene mutations of SP-C or other genes to explain these particular pathological findings and the low DLCO observed in this family.