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Biomedical subjects

A Okada

Publications and source records attributed to A Okada.

At least 343 records · Page 19Linked to original sources
PubMed1990

Congenital dilatation of the bile duct in 100 instances and its relationship with anomalous junction.

Congenital dilatation of the bile duct (CDBD) or choledochal cyst has been demonstrated to be associated with an anomalous junction of the pancreaticobiliary ductal system. Multifarious clinical signs and symptoms of CDBD have been shown to be closely related with the presence of this anomalous junction. In the present study, 100 instances of CDBD treated surgically at our institutions during a 30 year period were classified into two types according to the morphologic features of dilatation of the bile duct; there were 77 instances of the cystic type and 23 of the cylindric type. Morphologic features of the lesion, clinical signs and symptoms and laboratory findings in these 100 instances were clinically analyzed. In almost all of the patients who were less than one year of age, the disease was of the cystic type and patients presented with either a palpable mass or jaundice as the main symptom. In patients more than one year of age, the disease was of either the cystic or cylindric type. A history of episodes of characteristic abdominal pain accompanied by elevated levels of serum amylase was present in 70 of the patients with the cystic type of disease and in all of the patients with the cylindric type. Histologic sections from the patients showed glandular formation with chronic inflammation, possibly a result of refluxed activated pancreatic juice; in contrast, histologic sections from the remaining patients of all ages showed only thickening of the fibrous layer. Thus, such variable morphologic features and clinical signs and symptoms in CDBD are highly dependent on two factors--the age at onset and the reflux of pancreatic juice into the bile duct through the common channel.

Abdominal Pain↗
PubMed1990

Contribution to the morphology of mitochondria with prismatic cristae in astrocytes of the inferior olivary nucleus of the cat.

The internal structure of mitochondria with prismatic cristae in astrocytes of the inferior olivary nucleus of the adult cat was examined. The interior of the mitochondria with prismatic cristae cut in cross-section can be divided into 2 areas: (1) a peripheral, rather structureless area, and (2) a central, highly organized area. The former is composed of the inner mitochondrial membrane and a small number of peripheral cristae protruding from the membrane and scattered dots. The latter is composed of numerous prismatic cristae arranged in almost hexagonal spacing and many dots which probably represent the transverse configuration of filaments oriented parallel to the cristae embedded in the matrix. For future comparative analysis, various quantitative observations on the fine structure of the central, highly organized area are described and discussed.

Animals↗
PubMed1989

Cell death of motoneurons in the chick embryo spinal cord. X. Synapse formation on motoneurons following the reduction of cell death by neuromuscular blockade.

Chronic treatment of chick embryos with neuromuscular blocking agents, such as curare, rescues motoneurons from naturally occurring cell death. In the present study, embryos treated with curare from E6 to E9 had 35% more motoneurons than controls on E10 and 42% more than controls on E16. Previous studies have shown that several aspects of motoneuron differentiation occur normally in curare-treated embryos. We report here that dendrite growth and arborization is also unaltered on E10 and E16 following curare treatment. A quantitative analysis of afferent synapses on motoneurons shows that the packing density of both axosomatic and axodendritic synapses is also normal on E10 in curare-treated embryos, despite the greater number of motoneurons present. This indicates that the interneurons that provide presynaptic input to motoneurons are able to compensate for the increased number of synaptic sites made available by curare treatment. However, by E16 the packing density of synapses is reduced by about half. Because motoneurons and their dendrites continue to grow between E10 and E16, the further increase in synaptic sites made available in curare-treated embryos apparently exceeds the compensatory capacity of presynaptic interneurons on E16. One can conclude from these results that the increased survival of motoneurons in curare-treated embryos is not owing to an increase in afferent synapses. Motoneurons in these embryos continue to survive in the face of either no change (E10) or a reduction (E16) in the number of axodendritic and axosomatic synapses. Therefore, increased motoneuron survival in this situation is very likely regulated primarily by motoneuron-target interactions.

Animals↗
PubMed1989

Comparison of phospholipid N-methylation activity in rat submandibular salivary gland and liver.

Successive phospholipid N-methylation from phosphatidylcholine to phosphatidylethanolamine in submandibular gland and liver microsomes proceeded without the addition of exogenous phospholipid substrate. Methylation activity in the submandibular microsomes showed different susceptibilities to various detergents than the liver enzyme and also partially required Mg2+. However, the three methylation steps could not be distinguished by their Mg2+ requirements. Ca2+ had no effect on the activity. The methylation activity in submandibular gland was much lower than in liver. Chronic administration of isoproterenol, which causes an increase of phosphatidylcholine in membrane phospholipids of salivary glands, decreased methylation activity in the submandibular gland. Thus the increase in phosphatidylcholine in isoproterenol-treated rat salivary glands may not be derived from the phospholipid methylation pathway, but may be due to stimulation of other routes of phosphatidylcholine metabolism.

Animals↗
PubMed1989

Perioperative change of plasma endotoxin levels in early infants.

As a preliminary study to elucidate the relationship of endotoxemia to postoperative morbidity, the plasma endotoxin levels in 64 surgical neonates were quantitated by the chromogenic limulus test (Toxicolor test; Seikagaku Kogyo, Tokyo, Japan). The preoperative levels of plasma endotoxin were 64 +/- 59 pg/mL in the group of infants with perforated peritonitis (n = 9), 63 +/- 51 pg/mL in the group of infants with gastroschisis (n = 7), and 15 +/- 16 pg/mL in the group of infants with ileus (n = 28), while the mean level was 6 +/- 5 pg/mL in the remaining 20 surgical neonates who had no signs of ileus or peritonitis. In the serial determination of plasma endotoxin in 28 neonates, the levels on the first postoperative day increased significantly compared with the preoperative levels (16 +/- 18 pg/mL to 46 +/- 25 pg/mL, P less than .01). They decreased gradually to 8 +/- 5 pg/mL within a week in 15 neonates who had no postoperative complications. However, in 13 neonates who had postoperative complications such as wound infection or postoperative ileus, the postoperative levels of plasma endotoxin increased to a much higher level and remained there. In this article the relationship of clinical endotoxemia to postoperative thrombocytopenia and hyperbilirubinemia is analyzed, and the usefulness of evaluating endotoxemia in surgical neonates is discussed.

Bacterial Infections↗
PubMed1989

[Surgical treatment of stage III and IV thymoma].

During past 15 years, 39 cases of thymoma were underwent surgical intervention. In these cases, invasive type, so called stage III and IV in Masaoka's classification were 19 cases. This report documents the results of extended operation in 19 patients treated for malignant thymoma. All patients had neoplasm which invaded adjacent structures; superior vena cava, pericardium, and lung. Eight patients had disseminated lesions in the pleural or pericardial cavities. All patients were underwent surgical exploration through median sternotomy (18 patients) or left thoracotomy (1 patient). Our surgical management to malignant thymoma is to have complete resection, even if tumor invades the great veins. Of 8 patients, superior vena cava and left innominate vein were resected with tumor and reconstructed with ringed PTFE. Mediastinal pleura and pericardium should be widely opened and intrapericardial or intrapleural disseminated lesions should be removed as far as possible. Malignant thymoma could be resected completely applying technique of vascular surgery. Good results were expected when tumor was resected with invading adjacent structures completely. Reoperation to the recurrent tumor is also important.

Humans↗
PubMed1989

[A case of bronchopulmonary aspergillosis recurring in a residual tuberculous cavity].

A 52-year-old man, who had undergone right upper lobectomy because of active tuberculosis 29 years before, was admitted with complaints of severe cough and expectation. Two years ago, he had pulmonary aspergillosis and was successfully treated with some anti-mycotic agents. This time his chest X-P showed fungus ball in a residual tuberculous cavity in the right upper field and he was diagnosed as pulmonary aspergilloma from the results of radiological findings, sputum culture, and serologic test. By bronchofiberscopy fungus ball was observed. With transbronchial infusion of Amphotericin B, intravenous administration of Miconazole and oral administration of Flucytosine, clinical symptoms have improved and lysis of fungus ball was observed. Sputum culture revealed Aspergillus flavipes group. Bronchopulmonary aspergillosis, which was incurable by surgical treatment because of underlying disease, was successfully treated with transbronchial infusion of Amphotericin B and administration of some anti-mycotic agents.

Amphotericin B↗
PubMed1988

Structure of the gamma/delta T cell receptor of a human thymocyte clone.

The CD3+, IL-2-dependent normal human thymocyte clone, CII, expresses on its surface a CD3-associated gamma/delta TCR. We have further elucidated the structure of this receptor from the nucleotide sequence of cDNA and genomic clones from CII that encode functional TCR-gamma and -delta chains. We find that the CII line expresses a C gamma 2 constant region that is a polymorphic form lacking a copy of an internal exon; the sequence of this constant region accounts for the size of the gamma chain and noncovalent linkage of gamma and delta chains in the CII TCR. The V gamma region used for the CII TCR is identical to the several previously characterized expressed human V gamma segments. Possible implications of this finding are discussed.

Base Sequence↗