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Biomedical subjects

N Sakuma

Publications and source records attributed to N Sakuma.

80 records · Page 5Linked to original sources
PubMedDate not supplied

Ultrastructure of pleural mesothelioma and pulmonary adenocarcinoma in malignant effusions as compared with reactive mesothelial cells.

OBJECTIVE: To determine the ultrastructural features of diffuse malignant pleural mesothelioma cells in cytologic specimens from pleural effusions. STUDY DESIGN: We retrospectively studied 35 pleural effusions: 12 diffuse malignant pleural mesotheliomas (8 epithelial type, 4 biphasic type), 12 pulmonary adenocarcinomas and 11 cases of reactive mesothelial cells. RESULTS: In the cytoplasm, reactive and malignant mesothelial cells had more-abundant intermediate filaments (P < .05, P < .01) and fewer free ribosomes (P < .001, P < .001) than adenocarcinoma cells. Reactive mesothelial cells had fewer mitochondria than mesothelioma cells (P < .05). Mesothelioma cells had longer, thinner microvilli on the cell surfaces (P < .001); length/diameter ratios of microvilli were 19.1 +/- 7.0 (mesothelioma) vs. 9.1 +/- 2.2 (adenocarcinoma) and 9.2 +/- 2.4 (mesothelial cells). Giant intercellular junctions (desmosomes or desmosomelike structures > 1 micron in length) were found in eight cases of mesothelioma. Core filaments or rootlets in microvilli were present in two cases of adenocarcinoma. CONCLUSION: Because cytologic specimens from pleural effusions were easy to obtain, we think ultrastructural cytology is useful in distinguishing mesothelioma from adenocarcinoma and benign effusions.

Adenocarcinoma↗
PubMedDate not supplied

Morphologic changes in intercostal muscle tissue associated with a viper (Agkistrodon halys blomhoffi) bite.

This study examined a 73-year-old woman who had been bitten in the right thumb by a viper (Agkistrodon halys blomhoffi). She suffered acute renal failure and respiratory failure after the bite. On the 20th day, respiratory failure persisted, although she had recovered from renal failure. Intercostal muscles were obtained by biopsy on the 40th day after the bite. Specimens were observed with enzyme-histochemical and electron microscopic techniques. The size of muscle fibers varied. Most of the smaller muscle fibers were enzyme-histochemically type 2C fibers. This was considered to be the regenerative stage of acute rhabdomyolysis. Ultrastructurally, two opposite types of changes, degeneration and regeneration, were mixed in the same areas. Muscle fibers might be continuously degenerated, and the regenerative fibers might also be degenerated. This study suggests that some slow allergic reactions to snake venom might bear some relation to the degenerative changes.

Aged↗
PubMedDate not supplied

Transport of acetaminophen conjugates in isolated rat hepatocytes.

The membrane permeabilities of acetaminophen glucuronide and sulfate produced through conjugative metabolism were examined in isolated rat hepatocytes. The glucuronide formed in hepatocytes was gradually released into the medium and its intracellular level decreased. Release of the sulfate formed in hepatocytes occurred more rapidly and its intracellular level remained almost constant. The permeability of acetaminophen was so rapid that it caused instantaneous equilibrium between hepatocytes and the medium. Its intracellular level thus decreased by conjugation reactions, but compensation for this decrease from the medium was soon made so that a constant intracellular level was resumed. The uptake of both preformed glucuronide and sulfate into hepatocytes indicated carrier-mediated transport. From these results, a pharmacokinetic model is proposed in which conjugative metabolism occurs in two consecutive steps: conjugative reactions of the parent compound taken up instantaneously into hepatocytes and membrane transport of conjugates into the medium. Changes in the amount of acetaminophen, its glucuronide, and its sulfate in the hepatocytes and medium as a function of time simulated according to the model closely agreed with those actually observed. Consequently, membrane permeability of the conjugates was concluded to be essential for conjugative metabolism.

Acetaminophen↗
PubMedDate not supplied

Adrenal catecholamine secretory responses in young and adult dogs.

To elucidate the secretory sensitivity of the adrenal medulla in young animals, a comparative study of the adrenal secretory reactivity in young and adult dogs was made. In the isolated perfused adrenal gland, acetylcholine, nicotine, muscarine (10(-6)-10(-4) M) and high K+ (15-45 mM) enhanced catecholamine release. The release of catecholamines, expressed per weight of adrenal gland and caused by cholinergic secretagogues, was significantly higher in young dogs than in adult dogs. The proportion of noradrenaline to adrenaline plus noradrenaline in the tissue was higher in young dogs. The proportion of noradrenaline in the effluent was higher by increasing the concentrations of the stimulants, up to a similar level of the tissue noradrenaline/noradrenaline+adrenaline ratio. In in vivo studies, the increase in catecholamine concentration, especially of noradrenaline, in the plasma of femoral arteries, induced by intravenous injection of nicotine, was higher in young dogs than in adult dogs. We also measured the catecholamine-synthesizing enzymes activities in the adrenal medulla. Tyrosine hydroxylase and phenylethanolamine-N-methyltransferase activities were lower in young dogs, but there was no difference in dopamine-beta-hydroxylase activity between young and adult dogs. These results may suggest that young dogs are more sensitive to cholinergic stimulation in spite of their low catecholamine-synthesizing enzyme activity.

Adrenal Medulla↗
PubMedDate not supplied

Changes in urinary excretion of catecholamines and their metabolites in pediatric dental patients.

To explain the changes in urinary excretion of catecholamines and their metabolites in pediatric dental patients, comparative measurements of three catecholamines (dopamine, noradrenaline and adrenaline), and five metabolites (3, 4-dihydroxyphenylacetic acid, normetanephrine, metanephrine, homovanillic acid, and vanillylmandelic acid) were made before and after dental treatment. The investigations were carried out in seven healthy young children between three and five years of age. All these children had previously displayed negative behavior in dental treatment. There were statistically significant increases (P < 0.05) in urinary noradrenaline, adrenaline, and normetanephrine levels during dental treatment. These results suggest that these three substances could be a useful tool for determining the occurrence of dental stress in children.

3,4-Dihydroxyphenylacetic Acid↗