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Biomedical subjects

F Nakamura

Publications and source records attributed to F Nakamura.

At least 217 records · Page 12Linked to original sources
PubMed1989

Systemic lupus erythematosus in a patient with refractory anemia.

A 69-year-old man was diagnosed as having refractory anemia (RA), accompanied by pancytopenia of two years' duration, myelodysplasia in all three cell lines, abnormal karyotype of 46, XY, 20q--in bone marrow cells, and positive antinuclear and DNA antibody tests. One year after his first visit, he developed arthritis and maculopapular erythematous rashes. The histologic features of the skin lesions were similar to those of in discoid lupus erythematosus. He was diagnosed as having systemic lupus erythematosus supervening refractory anemia.

Aged↗
PubMed1989

[Empirical antibiotic therapy in febrile neutropenic patients with acute leukemia].

One hundred and ninety-five episodes of fever during the neutropenic phase of chemotherapy in 49 patients with acute leukemia from 1984 to 1987 were analyzed with the following results: 1) Febrile episodes occurred in 80 percent of the neutropenic (less than 500/microliters) phase lasting more than 7 days after chemotherapy. 2) Febrile episodes consisted of 44 (22%) of established septicemia and 111 (57%) of suspected septicemia. 3) The pathogens causing septicemia were 8 GPC, 38 GNB (22 Pseudomonas species) and 6 fungi. Fungemia was confirmed on an average of 4.8 days after the onset of fever. The mortality of septic events was 10 out of 17 episodes (59%) when treated with antibiotics alone, while 8 out 27 (30%) with the combination of antibiotics plus antifungal drugs. 4) The mortality of suspected sepsis was only 2 out of 111 episodes. Eighty-three (75%) of these 111 episodes responded to antibiotics alone, while 26 (23%) cases needed antibiotics plus antifungal drugs. Our results suggest that in febrile neutropenic patient empiric broad-spectrum antibiotic therapy should be initiated which is especially effective for Pseudomonas species, but if fever persists despite more than 4 or 5 days of antibiotic therapy, additional antifungal therapy should be considered.

Acute Disease↗
PubMed1988

Dome formation of keratin-containing agranular cells from rat anterior pituitary gland in vitro.

A certain kind of cell in the pituitary gland exhibited immunoreactive keratin and dome formations in vitro. We obtained epithelial cells, which were able to subculture, from the outgrowth of anterior pituitary organ cultures. These cells lacked hormone secretory granules and exhibited immunoreactive keratin. Furthermore, they produced dome formations or cystic structures in monolayer culture and under three-dimensional culture condition using type I collagen gel. Dome formation was stimulated by dibutyryl cyclic AMP (dbcAMP, 10(-3) to 10(-5) M). Their responsiveness to dbcAMP is similar to that of several other epithelial cells that possess transport functions in vivo and in vitro. Although the origin of our cultured cells is unknown, these cells formed dome formations that possessed transport function and were related to cystic structures in the pituitary gland in vivo.

Animals↗
PubMed1988

Fiberoptic angioscopy of cardiac chambers, valves, and great vessels using a guiding balloon catheter in dogs.

The applicability of fiberoptic angioscopy with a guiding balloon catheter to observe the cardiac chambers, valves and the great vessels was examined in anesthetized dogs. A No. 11 French guiding balloon catheter (balloon diameter 50 French) was introduced through either the right jugular vein or the right femoral vein into the right heart, and then a fiberscope (4.3 French in diameter) was introduced through the catheter into the right heart in 10 dogs. The balloon was inflated with air and gently pushed against the luminal surface, warm saline was infused through the catheter to displace the blood, and the luminal surfaces were photographed on 16 mm color cinefilms. Pulmonary angioscopy was also performed in these dogs. Similarly, the guiding catheter and fiberscope were introduced through the right common carotid artery into the left ventricle for observation of the luminal changes in the other 10 dogs. The luminal surfaces of the superior vena cava, right atrium, right ventricle, and pulmonary artery could be observed in all dogs. The trabeculae of the left ventricle, contracting and relaxing synchronously with the cardiac beat, could also be observed in all dogs. However, observations of the tricuspid valve, aortic valve, papillary muscle, and chordae were successful in only some dogs. Postmortem examinations revealed no obvious endocardial or intimal damage. The results indicate the applicability and safety of angioscopy guided by a balloon catheter for observations of the luminal changes in the cardiac chambers and great vessels.

Animals↗
PubMed1987

Chromosome aberrations and sister chromatid exchanges in Chinese hamster ovary cells: evaluations of 108 chemicals.

Results from the testing of 108 coded chemicals in Chinese hamster ovary (CHO) cells for the induction of chromosome aberrations and sister chromatid exchanges (SCEs) are presented. All chemicals were tested with and without exogenous metabolic activation, using protocols designed to allow testing up to toxic doses. Cell harvest times could also be extended if chemical-induced cell cycle delay was seen. Chromosome aberrations were induced by 43 of the chemicals, and 66 induced SCEs; 37 of the chemicals were positive for both endpoints.

Animals↗
PubMed1987

Cystlike structures derived from the marginal cells of Rathke's cleft in rat pituitary grafts.

Hemipituitary glands from 30 rats were isotransplanted under renal capsules. At 1, 2, 4, 7 and 20 days after transplantation, the grafts were examined by light and electron microscopy. Two days after transplantation, the central area of graft showed necrosis; however, the peripheral area, where marginal cells of Rathke's cleft were ingesting the remnants of necrotic glandular cells, survived. Four days after transplantation, mitotic figures of marginal cells were observed. Seven days after transplantation, the damaged area of the graft disappeared, and Rathke's cleft was completely lined by marginal cells. Remnants of necrotic glandular cells were not seen in intercellular spaces or in the cytoplasm of marginal cells. Cystlike structures formed in the grafts; some were connected to Rathke's cleft by narrow cavities. The cavity-lining cells of the cysts were agranular and similar to those that lined Rathke's cleft. At 20 days after transplantation, granular cavity-lining cells appeared. It is suggested that marginal cells of immature rats can differentiate into granular cells.

Animals↗
PubMed1987

Angiographic and angioscopic observations of the arterial luminal changes induced by vasospasm.

Angiography and angioscopy were used to examine arterial luminal changes induced by experimental vasospasm. The right common carotid artery of the dog was perfused with Krebs-Henseleit solution at a constant pressure, 3,4-diaminopyridine (DAP), a selective potassium channel blocker was applied on the adventitia, and the luminal changes were observed with angiography and angioscopy. Angiographically vasospasm (defined as a reduction in the internal diameter to less than 50% of the control value) was always induced by the topical application of 5 X 10(-1) mol/L DAP. The internal diameter decreased to 25% +/- 7% (mean +/- standard error, n = 6) 15 minutes after the application. The vasospasms propagated 2.7 +/- 0.6 and 1.1 +/- 0.3 cm downstream and upstream, respectively. Angioscopy showed that the lumen narrowed gradually and concentrically. Perfusion of the artery during vasospasm for 15 minutes with a backflow of blood from the contralateral artery resulted in thrombosis at the spastic segment. The results indicate that carotid vasospasm can be constantly induced by DAP, thrombosis occurs in the spastic artery, and angioscopy is useful for serial observation of the luminal changes induced by vasospasm.

4-Aminopyridine↗
PubMed1987

Percutaneous coronary angioscopy in patients with ischemic heart disease.

Percutaneous transluminal coronary angioscopy was performed during routine coronary angiography in seven patients and during PTCA in one patient with ischemic heart disease. A flexible fiberscope with an external diameter of 1.4 mm was introduced through an 8F or 9F guiding catheter used for PTCA into the coronary arteries. Warmed saline solution (15 to 20 ml) was injected through the guiding catheter into the coronary arteries for replacement of blood. Twenty-one of the 31 coronary segments were visualized and photographed on color cinefilms. The lumen of the atherosclerotic segment showed narrowing with smooth surface or with spiral folds. PTCA caused dilatation of the stenosed segment with scattered thin thrombi. These findings indicate the usefulness of angioscopy to observe luminal changes in the coronary arteries of patients with ischemic heart disease.

Aged↗
PubMed1986

Immunohistochemical and ultrastructural study of anterior pituitary cells in the female Afghan pika, Ochotona rufescens rufescens.

An immunohistochemical study of the anterior pituitary gland of the female Afghan pika was carried out to distinguish the ultrastructural features of GH, PRL, ACTH, TSH and LH cells. The histochemically identified GH cells resembled ultrastructurally oval or round GH cells of the rat laden with large, dense secretory granules. PRL cells were divided into three subtypes based on differences in the diameter of their spherical secretory granules. They lacked polymorphic or irregularly shaped secretory granules. ACTH cells resembled ultrastructurally, in some respects, Siperstein's "corticotrophs" of the rat with peripheral arrangement of secretory granules. However, they were not always stellate, but elongate or angular in shape. The dense secretory granules were concentrated in the peripheral area of cytoplasm. TSH cells were non-stellate, but usually oval in shape, containing the smallest spherical secretory granules (100-200 nm in diameter). Almost all LH cells reacted also with FSH antiserum. They were irregular in shape, sometimes in contact with or surrounded the GH cells. They contained an abundance of medium-sized secretory granules (140-260 nm in diameter) which were larger than those in the LH cells of the female rat throughout the estrous cycle. Large secretory granules in the LH cells of the female pika seemed to be related to the endocrine state of persistent estrus.

Adrenocorticotropic Hormone↗
PubMed1986

Hymenolepis nana: passive transfer of mouse immunity by T-cell subset of phenotype Lyt-1.

Mesenteric lymph node cells obtained from donor mice (BALB/c strain) actively immunized by oral inoculation with Hymenolepis nana eggs were syngeneically transferred by intravenous injection into athymic nude mice previously uninfected. The adoptively immunized recipients were then challenged with 1000 H. nana eggs 2 days after cell transfer. The degree of immunity transferred was assessed by examining cysticercoids developed in the intestinal villi of the recipients on Day 4 of challenge infection. The criterion for success in cell transfer of immunity was the complete rejection of cysticercoids as was generally expected in mice infected previously. The transfer of 1.5 X 10(8) immune mesenteric lymph node cells obtained from donors immunized 4 days before cell collection resulted invariably in the complete rejection of cysticercoids, though not less than this cell dosage. The immunity was passively transferable to recipients by T cells, especially by T-cell subset of phenotype Lyt-1 but not those of phenotype Lyt-2.3 and Lyt-1.2.3. However, 1.5 X 10(8) immune mesenteric lymph node cells obtained from donors immunized 21 days before cell transfer and 1.5 X 10(8) immune spleen cells obtained from donors immunized 4 days before cell transfer had little or no effect on the rejection of cysticercoids.

Animals↗
PubMed1986

Morphological characterization of LH secretory granule response to LHRH and calmodulin inhibitor.

A quantitative electron microscopy study was carried out to characterize the luteinizing hormone (LH) contained secretory granules in response to exogenous luteinizing hormone releasing hormone (LHRH) alone or in combination with calmodulin inhibitor (W13) in orchidectomized rats pretreated with estrogen. The plasma LH concentration rose quickly 30 min after a single large LHRH injection, and then gradually increased further until 150 min. However, the rise was attenuated by supplemental administration of W13 30 min after LHRH exposure. The mean diameter of secretory granules quickly decreased inversely to the increase of plasma LH concentration after LHRH injection. However, the mean diameter increased significantly in accordance with the complete attenuation of the increase in LH release caused by administration of W13. There was an inverse correlation between the diameter of secretory granules and plasma LH concentration. Small secretory granules with low electron density frequently appeared in castration cells after LHRH injection. It is concluded that reduced size and density of secretory granules is the main morphological standard responsible for extraordinary LH secretion from gonadotrophs.

Animals↗