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Biomedical subjects

M Akira

Publications and source records attributed to M Akira.

At least 55 records · Page 3Linked to original sources

Characterization of a cDNA for human protein C inhibitor. A new member of the plasma serine protease inhibitor superfamily.

A cDNA library in lambda-phage lambda gt11 containing DNA inserts prepared from human liver mRNA was screened with monoclonal antibodies to human protein C inhibitor. Six positive clones were isolated from 6 X 10(6) phages and plaque purified. The cDNA in the phage containing the largest insert, which hybridized to a DNA probe prepared on the basis of the amino-terminal amino acid sequence of the mature inhibitor, was sequenced. This cDNA insert contained 2106 base pairs coding for a 5'-noncoding region, a 19-amino acid signal peptide, a 387-amino acid mature protein, a stop codon, and a long 3'-noncoding region of 839 base pairs. Based on the amino acid sequence of the carboxyl-terminal peptide released by cleavage of protein C inhibitor by activated protein C as well as by thrombin, the reactive site peptide bond of protein C inhibitor is Arg354-Ser355. Five potential carbohydrate-binding sites were found in the mature protein. The high homology of the amino acid sequence of protein C inhibitor to the other known inhibitors clearly demonstrates that protein C inhibitor is a member of the superfamily of serine protease inhibitors including alpha 1-antichymotrypsin, alpha 1-antitrypsin, antithrombin III, ovalbumin, and angiotensinogen. Based on the difference matrices for these proteins, we present possible phylogenetic trees for these proteins.

Amino Acid Sequence↗

Ultrasonography of mediastinal teratoma.

We have studied real-time sonograms of 11 surgically proven benign mediastinal teratomas. Eight cystic teratomas were sonographically visualized as various kinds of masses: four complex, two solid, and two cystic. The echo patterns of cystic teratomas were determined by the serous or nonserous nature of the cysts. In the presence of serous fluid, the tumor was visualized as a cystic mass. If, on the other hand, the cyst of the tumor was nonserous or was sebaceous, it appeared as a solid or complex tumor. The remaining three solid teratomas, which had some small cysts, appeared as complex tumors.

Adult↗

Molecular cloning of the gene encoding rabbit tumor necrosis factor.

A rabbit genomic DNA library was screened using a cloned cDNA encoding rabbit tumor necrosis factor (TNF) as a probe. The entire gene sequence appears to be contained within a 3.2-kb Eco RI fragment. Comparison of the nucleotide sequence of the gene with that of the cDNA showed that the gene consists of four exons. The nucleotide sequence of the rabbit TNF gene is very homologous to that of the human TNF gene. Southern hybridization of the genomic DNAs showed that there is likely only a single TNF gene in each of the rabbit and human genomes.

Animals↗

Functioning parathyroid cyst extending from neck to anterior mediastinum. Diagnosis by sonography and computed tomography.

A parathyroid cyst was evaluated by sonography and computed tomography (CT) in a patient with hyperparathyroidism. Sonography demonstrated a cystic lesion near the left lower pole of the thyroid, extending into the anterior mediastinum. On CT, the parathyroid cyst had a slightly high attenuation (30 H), with a smooth wall demonstrated after intravenous administration of contrast material. Fine-needle aspiration biopsy of the cyst showed elevated parathyroid hormone (PTH) level. The lesion probably represents cystic degeneration of an adenoma.

Aged↗

Optimal dose of hepatobiliary contrast agent for MR cholangiography: experimental study in rats.

The purpose of this study is to clarify the optimal dose of gadolinium-ethoxybenzyl-diethylenetriaminepentaacetic acid (Gd-EOB-DTPA) for cholangiography in conventional T1-weighted imaging. We divided 30 rats into three dose groups (3, 10, and 30 micromol/kg). For the in vitro study, we collected bile and measured the concentration of gadolinium in bile after Gd-EOB-DTPA injection. T1-weighted images of the collected bile were obtained for measurement of signal intensity. For the in vivo study, we obtained T1-weighted images before and after injection and evaluated bile duct/liver contrast by the signal intensity ratio and visual assessment of the images. The gadolinium concentration had an early peak; however, the signal intensity of the bile had a later peak because of the high gadolinium concentration during the early phase, which induced a T2-shortening effect. Optimal bile duct/liver contrast was obtained in the 10-micromol/kg groups at all time points. We conclude that the optimal dose of Gd-EOB-DTPA for MR cholangiography in rats is 10 micromol/kg, one-third of the dose used in liver imaging.

Animals↗

CT findings in "pseudoalveolar" sarcoidosis.

To determine the specific high resolution CT (HRCT) features for "pseudoalveolar" sarcoidosis, we reviewed HRCT of 10 patients with pathologically proven sarcoidosis. On HRCT the lesions of pseudoalveolar sarcoidosis were shown as homogeneous or inhomogeneous opacities 1-4 cm in diameter located either along the bronchovascular bundles or in the lung periphery adjacent to the pleural surface. The margin was irregular, and numerous nodules 1-2 mm in diameter were observed in the surrounding lung. Air bronchograms were observed in 6 patients. In addition to these lesions, other CT abnormalities such as nodules, groundglass opacities, thickened bronchovascular bundles, and interlobular septa were found in all 10 cases. Good response of pseudoalveolar sarcoid lesions to administration of corticosteroid was observed in all three cases in which follow-up CT was available.

Adult↗

Thin-section CT findings in rheumatoid arthritis-associated lung disease: CT patterns and their courses.

PURPOSE: The purpose of this study was to describe the long-term follow-up CT evaluation in rheumatoid arthritis (RA)-associated lung disease. METHOD: Thin-section CT scans from 29 patients with RA and suspected associated lung disease were reviewed. Twenty-two patients underwent sequential CT evaluation during 3 to 108 months of follow-up (mean 28 months). Histologic comfirmation of pulmonary involvement was available in 19 patients. RESULTS: Three major patterns were identified: reticulation with or without honey-combing (n = 19), centrilobular branching lines with or without bronchial dilatation (n = 5), and consolidation (n = 5). Reticulation and centrilobular branching lines corresponded to usual interstitial pneumonia (n = 14) and bronchiolitis obliterans (n = 1), respectively. Consolidation corresponded to bronchiolitis obliterans organizing pneumonia (BOOP; n = 3) and coexistent chronic eosinophilic pneumonia (CEP) and BOOP (n = 1). Patients with reticulation had rapid deterioration when there was new appearance of multifocal areas of ground-glass attenuation. Centrilobular branching lines progressed to bronchiectasis in one case. There was mild progression of existing bronchiectasis associated with centrilobular branching lines in one case. Area of consolidation in two patients with BOOP and one with coexistent CEP and BOOP evolved into honeycombing at serial CT. CONCLUSION: Thin-section CT is a noninvasive technique for monitoring disease morphology in RA-associated lung disease. Initial CT findings and their evolution on sequential examinations may be useful in evaluating prognosis.

Adult↗

Transient radiographic progression during initial treatment of pulmonary tuberculosis: CT findings.

PURPOSE: A study was undertaken to describe the thin-section CT features of transient radiographic progression during initial treatment of active pulmonary tuberculosis. METHOD: The CT scans of 13 patients who developed transient radiographic progression during initial treatment of pulmonary tuberculosis were evaluated and compared with those of 10 patients with true progression of pulmonary tuberculosis. Two patients underwent transbronchial lung biopsy for pathologic evaluation of new lesion. RESULTS: Eight patients had increased opacity at the site of their original lesion, whereas five had new opacities elsewhere: ipsilateral (n = 3) or contralateral (n = 1) to the original lesion or both (n = 1). Relatively extensive areas of ground-glass attenuation were concomitantly depicted in three of the eight patients with progression in the area of the original lesion. In those with progression ipsilateral or contralateral to the lesion, the character of the new lesions was ground-glass opacity and/or consolidation mainly in the subpleural region. Transbronchial lung biopsy specimens obtained from two patients showed intraluminal organizing exudates and thickened alveolar septa with lymphocyte infiltration, whereas the dominant CT findings of true progression of pulmonary tuberculosis were nodules (n = 8) or centrilobular nodules (n = 7). CONCLUSION: Thin-section CT may be useful to differentiate transient radiographic progression from true progression of pulmonary tuberculosis.

Adult↗

Acute respiratory distress syndrome and acute interstitial pneumonia: comparison of thin-section CT findings.

PURPOSE: The purpose of this work was to compare the thin-section CT findings of acute respiratory distress syndrome (ARDS) with those of acute interstitial pneumonia (AIP). METHOD: The thin-section CT scans from 25 patients with ARDS and 25 with AIP were independently assessed by two observers without knowledge of clinical and pathologic data. The presence, extent, and distribution of various CT findings were independently analyzed. RESULTS: Honeycombing was seen more frequently in lobes of patients with AIP (26%) than in lobes with ARDS (8%) (p < 0.001). Compared with patients with ARDS, a greater number of patients with AIP had a predominantly lower lung zone distribution (p < 0.05) and a symmetric distribution (p < 0.05) of the parenchymal abnormalities. CONCLUSION: Patients with AIP have a greater prevalence of honeycombing and are more likely to have a symmetric bilateral distribution and a lower lung zone predominance than patients with ARDS. However, significant overlap exists among the CT findings.

Acute Disease↗

Can acute interstitial pneumonia be differentiated from bronchiolitis obliterans organizing pneumonia by high-resolution CT?

PURPOSE: In the early stages, clinical and chest radiographic findings of acute interstitial pneumonia (AIP) are often similar to those of bronchiolitis obliterans organizing pneumonia (BOOP). However, patients with AIP have a poor prognosis, while those with BOOP can achieve a complete recovery after corticosteroid therapy. The objective of this study was to identify differences in high-resolution CT (HRCT) findings between the two diseases. METHODS: The study included 27 patients with AIP and 14 with BOOP who were histologically diagnosed [open-lung biopsy (n=7), autopsy (n=17), transbronchial lung biopsy (n=17)]. The frequency and distribution of various HRCT findings for each disease were retrospectively evaluated. RESULTS: Traction bronchiectasis, interlobular septal thickening, and intralobular reticular opacities were significantly more prevalent in AIP (92.6%, 85.2%, and 59.3%, respectively) than in BOOP (42.9%, 35.7%, and 14.3%, respectively) (p<0.01). Parenchymal nodules and peripheral distribution were more prevalent in BOOP (28.6% and 57.1%, respectively) than in AIP (7.4% and 14.8%, respectively) (p<0.01). Areas with ground-glass attenuation, air-space consolidation, and architectural distortion were common in both AIP and BOOP. CONCLUSION: For a differential diagnosis of AIP and BOOP, special attention should be given to the following HRCT findings: traction bronchiectasis, interlobular septal thickening, intralobular reticular opacities, parenchymal nodules, pleural effusion, and peripheral zone predominance.

Acute Disease↗