Search PubMed⌕ Search

Biomedical subjects

A Kikuta

Publications and source records attributed to A Kikuta.

88 records · Page 5Linked to original sources
PubMed1985

Multiple efferent arterioles of the human kidney glomerulus as observed by scanning electron microscopy of vascular casts.

About three thousand resin vascular casts of human renal glomeruli were examined with a scanning electron microscope, and two extremely rare glomeruli with quadruple or quintuple efferent arterioles were found. Each of these multiple efferent arterioles arose independently from the glomerular capillary tuft supplied by a single afferent arteriole. In addition, 34 glomeruli possessed double or triple efferent arterioles and two showed double afferent arterioles. In one of the former cases, one of the double efferent arterioles had a heterotopic origin near the urinary pole of the glomerulus. No glomerulus with triple or more afferent arterioles was noted.

Arterioles↗
PubMed1985

Blood vascular bed of the rat pituitary intermediate lobe, with special reference to its development and portal drainage into the anterior lobe. A scanning electron microscope study of vascular casts.

Blood vascular beds of the rat pituitary intermediate lobes were reproduced by injection of low viscosity methacrylate media, and then observed with a scanning electron microscope. Although the intermediate lobes of newborn and pubescent rat were poorly vascularized, the adult rat intermediate lobe contained numerous capillaries forming a fairly independent network whose density, however, was not so great as in the anterior and posterior lobes. The vascular network of the intermediate lobe could be divided into two parts: a superficial plexus close to the anterior lobe, and a deep one close to the posterior lobe, though the two plexuses were continuous with each other. The superficial plexus consisted of anastomosing capillaries, and the deep one of non-anastomosing capillaries with a palisade-fashioned arrangement. The superficial plexus seemed crucially important for the blood supply of the intermediate lobe since it developed or thickened as the animals aged. The superficial plexus received its proper afferent vessels from the middle and posterior hypophyseal arteries and emitted its proper efferent vessels continuous with the sinusoidal capillaries of the anterior lobe. The capillaries of the deep plexus usually communicated with the arterial capillaries of the posterior lobe and possibly represented another afferent route to the superficial plexus. This paper, thus, strongly suggests a portal circulation from the intermediate lobe to the anterior lobe though its functional significance is unknown.

Aging↗
PubMed1984

Relationship between chromaffin cells and blood vessels in the rat adrenal medulla: a transmission electron microscopic study combined with blood vessel reconstructions.

The rat adrenal medulla architecture was examined using a combination of medullary blood vessel reconstructions and transmission electron microscopy. The peripheral radicles of the central vein and the medullary capillaries of the medullary arteries were thus precisely identified in the electron microscopic observations. The observations confirmed that the peripheral segments of the central vein were sinusoidal vessels with an attenuated and fenestrated endothelial wall. No ultrastructural differences were observed between segments lined by epinephrine-storing cells and those lined by norepinephrine-storing cells. The findings suggest that these peripheral segments of the adrenal central vein were sites of cortical hormonal effects on the adrenal medulla. The vessel structure does not support the hypothesis that medullary chromaffin-cell development is controlled by selective distribution of adrenal blood vessels.

Adrenal Medulla↗
PubMed1983

Microvasculature as studied by the microvascular corrosion casting/scanning electron microscope method. I. Endocrine and digestive system.

This paper reviews firstly the microvascular corrosion casting/scanning electron microscope method and secondly the microvascular organization of endocrine and digestive system as revealed by this technique. Detailed descriptions of the microvascular arrangement of the hypophysis, pineal body, thyroid gland, pancreas, adrenal gland, salivary gland, liver, stomach and small intestine are given. Various hypotheses are also proposed regarding the physiological significance of the microcirculatory patterns observed.

Adrenal Glands↗
PubMed1983

Conductive staining of biological specimens for scanning electron microscopy with special reference to ligand-mediated osmium impregnation.

Biological specimens for scanning electron microscopy are made electron-conductive and non-charging by intense osmication with tannic acid, thiocarbohydrazide, hydrazine hydrate or other bifunctional ligands (or mordants). Such osmication also minimizes tissue shrinkage during dehydration and drying, reduces tissue damage during metal coating and scanning observations, and circumvents the use of a thick metal coating which hinders high resolution. Intense osmication when repeated eliminates the need for a metal coating and produces a well-contrasted scanning image with good resolution. Moreover, such osmication reduces tissue damage during ion implanting, enhances the depth of imaging, allows x-ray microanalysis without coated metals, and permits resin-embedded observations, as well as continuous or repeated microdissections in the scanning electron microscope without charging. Intense osmication forms a surface coat or thickens the cell membrane. This surface coat consists of electron dense deposits of 4-20 nm thickness. The hydrazine hydrate-osmium method can be used in the vapor phase. The vapor phase application has the advantage of staining even plastic samples for non-metal-coated scanning electron microscopy.

Animals↗
PubMed1982

Microcirculation of the rat adrenal gland: a scanning electron microscope study of vascular casts.

Blood vascular beds of the rat adrenal gland were filled with methacrylate resin and observed with a scanning electron microscope. The classical findings on mammalian adrenal glands of Flint (1900), Bennett and Kilham (1940), and Gersh and Grollman (1941) were confirmed. The cortical capillaries arise from the cortical arteries and converge at the corticomedullary junction into the peripheral venous radicles which flow into the tributaries of the central vein. The medullary capillaries originate from the medullary arteries and drain through the deep venous radicles into the tributaries of the central vein. No direct connection between the cortical and medullary capillaries was noted except for rare communications via the peripheral venous radicles. These findings show that most of the cortical blood, rich in glucocorticoids, flows in the medulla, not through the medullary capillary plexus but exclusively through the radicles of the central vein. Evidence for adrenal portal vessels could not be found.

Adrenal Cortex↗
PubMedDate not supplied

Sarcoid reaction in primary neuroblastoma: case report.

We present a unique case of a 9-month-old infant with a left adrenal neuroblastoma with sarcoid reaction, detected by mass screening. There was no clinical evidence indicating systemic sarcoidosis or pulmonary mycobacterial infection. Histological examination of the resected adrenal tumor revealed many noncaseating epithelioid granulomas with lymphocytic infiltrate, composed of epithelioid cells and few giant cells, arising in tumor parenchyma and fibrovascular stroma. Most of the lymphocytes in the granulomas were CD3- or CD45RO-positive T cells, with fewer being CD20-positive B cells. The lymphocytes in the epithelioid granulomas expressed CD4 or CD8, but not CD56 and CD57. CD4-positive cells were observed more within the granulomas (internal area) than in the surrounding area (external area) of the same granulomas, while most of the CD8-positive cells were seen consistently at the outer margin of the granulomas (marginal zone). CD45RA-positive T cells were observed predominantly in the external area. The results of immunostaining demonstrated that lymphocytes in granulomas of this case showed the same distribution pattern as that seen in systemic sarcoidosis. Although the sarcoid reaction is a phenomenon known to be associated with the region of cancer, granuloma within the primary neuroblastoma is extremely rare. The sarcoid reaction in the present case of neuroblastoma may be associated with a delayed-type hypersensitivity reaction, and its significance and relevance still remain obscure.

Adrenal Gland Neoplasms↗
PubMedDate not supplied

Diagnosis of congenital glucose-galactose malabsorption by measuring sugar- and amino acid-evoked potential differences in jejunum in vivo.

A girl who was clinically suspected of having congenital glucose-galactose malabsorption was investigated for sugar- and amino acid-evoked potential differences in the jejunum in vivo using a jejunal perfusion technique. She was fed an ordinary diet without suffering diarrhea at the time (at age 2) of this study. Her nutritional condition and development were normal. The disaccharidase activities of a biopsy specimen of the jejunal mucosa, which were assayed at 1 year of age when she was not having diarrhea, were normal. Jejunal perfusion of 100-mM solutions of D-glucose or D-maltose evoked no significant change in the electrical potential difference. On the other hand, 100 mM of L-glycine or L-leucine solution evoked a normal increase of the lumen negative potential difference (4.4 mV and 3.6 mV, respectively). Therefore, the patient was diagnosed as having congenital glucose-galactose malabsorption due to a defect of Na-dependent glucose-galactose active transport. These findings indicate that the measurement of sugar- and amino acid-evoked potential differences is a simple and reliable method for the diagnosis of congenital glucose-galactose malabsorption.

Amino Acids↗
PubMedDate not supplied

Overview of clinical studies of childhood acute lymphoblastic leukemia for more than ten years by the Japanese Children's Cancer and Leukemia Study Group.

Since 1981, the Children's Cancer and Leukemia Study Group (CCLSG) has developed a series of protocols for treatment of acute lymphoblastic leukemia (ALL) in childhood. In the first randomized controlled study of the 811 protocol (1981-1983) a comparison of conventional daily 6-mercaptopurine and methotrexate with a pulsed regimen of the two drugs was performed. The superiority of the pulsed regimen was shown. In the next 841 protocol (1984-1987) a comparison of two drugs and three drugs during induction therapy was conducted. The three-drug regimen resulted in a significantly higher event-free survival (EFS) rate. In the 874 protocol (1987-1990) two regimens with or without cranial irradiation were randomly compared, and there was no significant difference between the two regimens for the standard-risk group. To further improve the EFS rate a risk group-directed protocol 911 was conducted starting in January 1991. Life-table analysis of serial CCLSG protocols revealed that the outcome of overall ALL has gradually improved with an increase of the EFS rate; 41.4% +/- 3.6% at 14 years for the 811 protocol, 51.3% +/- 3.5% at 11 years for the 841 protocol, 56.7% +/- 3.1% at 8 years for the 874 protocol, and 78.2% +/- 3.1% at 4 years for the more recent 911 protocol.

Antineoplastic Combined Chemotherapy Protocols↗