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Biomedical subjects

N Kitamura

Publications and source records attributed to N Kitamura.

At least 415 records · Page 23Linked to original sources
PubMed1988

An immunohistochemical study of gut endocrine cells in two species of insectivorous vespertilinid bats (Chiroptera: Pipistrellus abramus and Plecotus auritus sacrimontis).

11 endocrine cell types immunoreactive for either 5-hydroxytryptamine (5-HT), somatostatin, gastrin, cholecystokinin (CCK), gastric inhibitory peptide (GIP), motilin, secretin, neurotensin, pancreatic glucagon, enteroglucagon or bovine pancreatic polypeptide (BPP) were found in gastrointestinal tract of 2 species of insectivorous bats. 5 of these 11 types of endocrine cells were located in the stomach and all 11 types of endocrine cells were found in the intestine. However, the distribution and relative frequency of each immunoreactive endocrine cell varied among the cell types and between the 2 species of bats examined. In Brunner's glands, gastrin- and 5-HT-immunoreactive cells were detected very rarely in Pipistrellus and only occasionally in Plecotus. The present results obtained from the insectivorous bats were compared with those of the sanguivorous vampire bats.

Animals↗
PubMed1987

Immunohistochemical study on the distribution of neuron-specific enolase- and peptide-containing nerves in the omasum of cattle.

The distribution of nerves containing immunoreactivity for substance P (SP), vasoactive intestinal polypeptide (VIP), leucine-enkephalin (LENK), and gastrin-releasing polypeptide (GRP) in the margin of the reticulo-omasal orifice, omasum, and omasal pillar of calves and cows was studied by immunohistochemistry. The general distribution of nerves was determined by means of neuron-specific enolase (NSE) antiserum and then compared to the distribution of immunoreactive (IR) nerves stained for the four peptides. Marked differences in the distribution of immunoreactive nerves were associated with age and the segment examined. SP-IR fibers were abundant in the musculature of the ungulate papillae at the reticulo-omasal orifice and in the smooth muscle of the omasal leaves, moderately dense in the omasal pillar, and low in density in the inner muscle layer of the reticulo-omasal orifice and in the muscle of the omasal wall. In order of decreasing abundance, the cell bodies of SP-IR nerves were found at the reticulo-omasal orifice, in the omasal wall, and in the omasal pillar. LENK-IR fibers, though less abundant, showed a pattern of distribution that was similar to that of SP-IR fibers. Nerve cell bodies showing weak immunoreactivity for LENK were detected rarely. Abundant VIP-IR fibers were present in the inner muscle layer of the reticulo-omasal orifice and in the omasal wall, while moderate numbers were seen in the omasal pillar: they were low in density in the ungulate papillae and omasal leaves. Cell bodies of VIP-IR nerves decreased in number through the omasum, reticulo-omasal orifice, and omasal pillar. The distribution of GRP-IR nerve fibers was similar to that of VIP-IR fibers, although GRP-IR fibers were less abundant. Nerve cell bodies showing weak immunoreactivity for GRP were detected rarely. The individual distribution of peptide-IR nerves was similar in the calf and cow, but immunoreactive nerves were far more abundant in the calf. The present study provides valuable information for discussion of the possible role of nerves in the regulation of omasal function.

Animals↗
PubMed1987

Differing expression patterns and evolution of the rat kininogen gene family.

The present investigation using molecular cloning and sequence analysis concerns the examination of the molecular basis for different expression patterns of two types of the rat kininogen genes. We show that the low molecular weight and high molecular weight forms of K kininogens are produced from a single gene through alternative usage of two 3'-coding regions, whereas only the low molecular weight forms of T kininogens are generated as a result of several mutational changes in the high molecular weight-specifying regions of both T-I and T-II kininogen genes. The mutational changes include a nucleotide substitution at the polyadenylation/processing signal site, nucleotide deletions resulting in the frame-shift mutation, and an insertion of the type 2 Alu-equivalent sequence. Because kininogens represent a multifunctional protein comprising the proteinase-inhibitory activity, the kinin moiety, and the clotting activity, these results present evidence indicating the molecular basis for the disappearance of a part of the gene functions. We also show that the K and T kininogen genes as well as the two T kininogen genes are extremely homologous, excluding and including the above mutational changes, respectively. These structural relationships allow us to envisage evolutionary processes for the generation of the rat kininogen gene family, particularly for the disappearance of a part of the gene functions.

Animals↗
PubMed1987

Differing utilization of homologous transcription initiation sites of rat K and T kininogen genes under inflammation condition.

Two types of rat kininogen mRNAs exhibit marked differences in the regulation of their expressions. The two T kininogen (T) mRNAs considerably increase under acute inflammation conditions, although no such increase occurs in the high molecular weight and low molecular weight K kininogen (K) mRNAs encoded by the same gene. This investigation examines the sequences of the 5' portions of the K and the two T genes and analyzes transcription initiation sites and their utilization at differently regulated conditions of the K and T genes. The sequence analysis indicates that the K and the two T genes are extremely homologous at the 5' portions as well as the 5'-flanking regions of at least 1.0 kilobase pairs. The S1 nuclease and primer extension analyses show that both T and K mRNAs start with three sets of the homologous initiation sites, and the utilization of the two 3'-side initiation sites of the T genes markedly increases under inflammation conditions. In contrast, no such elevation is observed for the three initiation sites of the K gene. Thus, although the sequences involved as transcription initiation sites are extremely homologous, their utilizations in the expressions of the K and T genes are regulated differently under inflammation conditions.

Amino Acid Sequence↗
PubMed1987

Reactive endosteal bone formation.

The microstructure of reactive endosteal new bone was examined using undecalcified ground sections in five pathologic conditions (bone metastasis from prostate cancer in seven cases, intervertebral osteochondrosis in five, Paget disease in four, chronic suppurative osteomyelitis in two, and fracture healing in one). To determine a basic form of rapid intramembranous bone formation, fetal rat calvaria and primitive bones made in clonal osteogenic cell culture were also observed. In slow bone-forming conditions, lamellar new bone was deposited on pre-existing trabecular surface and caused trabecular thickening on radiographs. In contrast, in rapid bone-forming conditions, woven bone was deposited as spicules extending from trabecular surface so as to form new networks in intertrabecular space. This causes obscurity of trabecular margins radiographically. Reactive endosteal bone formation may be nonspecific and have a significance for assessing the virulence of underlying pathologic conditions like periosteal reactions.

Aged↗
PubMed1987

Molecular biology of the angiotensinogen and kininogen genes.

In order to investigate the structures and expressions of the angiotensinogen and kininogen genes, we have isolated cDNA and genomic clones and characterized their structures. The following results were obtained. (a) The primary structures of rat and human angiotensinogens and bovine, human, and rat kininogens were determined, and they exhibit characteristic features. (b) Angiotensinogen and alpha 1-antitrypsin are related in not only protein structures but also gene organizations. (c) Angiotensinogen mRNA is synthesized not only in the liver but also in the brain, kidney, lung, adrenal gland, and ovary. (d) Angiotensinogen mRNA markedly increased in the liver but not in the brain after induction of acute inflammation. (e) Low molecular weight (LMW) and high molecular weight (HMW) kininogen mRNAs are generated from a single gene by alternative RNA processing events. (f) At least four types of kininogen mRNAs exist in rat liver. Two of them are LMW and HMW kininogen mRNAs, while the other two encode additional forms of kininogens (T-kininogens). (g) Two T-kininogen mRNAs but not LMW and HMW kininogen mRNAs dramatically increased after induction of acute inflammation, and T-kininogen turned out to be identical to alpha 1-major acute phase protein. (h) Kininogens have multifunctional domains; an amino-terminal domain for cystein proteinase inhibitor, a bradykinin moiety, and in the case of HMW kininogen a carboxyl-terminal domain for a cofactor of blood coagulation.

Angiotensinogen↗
PubMed1987

End plate of the discovertebral joint: degenerative change in the elderly adult.

Degenerative change at the end plate of the discovertebral joint was studied in the elderly adult by correlating the histologic and radiographic findings. Undecalcified ground sections were made from 21 autopsied lumbar spines that demonstrated no evidence of disease except age-related osteoporosis. Histologic examination showed that the cartilaginous end plates were degenerated to various extents and were replaced by subchondral bone proliferation (endochondral bone formation) in the direction of the joint space. In advanced cases, this histologic finding was reflected in radiographs as a subchondral sclerotic zone protruding toward the disk space. The degree of end-plate change was positively correlated with disk-space narrowing and the vacuum phenomenon (degeneration of the nucleus pulposus) but not with osteoporosis and vertebral compression. Anatomically and functionally, this may be the most common form of degeneration at the discovertebral joint end plate. Further study will be necessary to clarify the process.

Aged↗
PubMed1987

Circulating 1,25-dihydroxyvitamin D concentrations in patients with renal cell carcinoma-associated hypercalcemia are rarely suppressed.

We measured serum 1,25-dihydroxyvitamin D concentrations in 18 patients with renal cell carcinoma-associated hypercalcemia. Only 2 patients (11%) had low serum 1,25-dihydroxyvitamin D (less than 15 pg/ml) levels, and the mean 1,25-dihydroxyvitamin D level in the 18 patients was 44 +/- 30 (+/- SD) pg/ml, not different from the value of 42 +/- 22 pg/ml in 75 age-matched normocalcemic patients with various malignancies. Eighty-seven percent (26 of 30) of the hypercalcemic patients with extensive skeletal metastases due to other malignancies or with hematological malignancies had suppressed serum 1,25-dihydroxyvitamin D levels (less than 15 pg/ml). In hypercalcemic patients with other malignancies and no skeletal metastases, only 54% (21 of 39) had low serum 1,25-dihydroxyvitamin D levels. The mean serum 1,25-dihydroxyvitamin D level in the latter group was 21 +/- 26 pg/ml, significantly lower than that in normocalcemic patients. In renal cell carcinoma-associated hypercalcemia, suppression of circulating 1,25-dihydroxyvitamin D concentrations is uncommon.

Adult↗
PubMed1987

An immunohistochemical study of the endocrine cells in the gastrointestinal mucosa of the Caiman latirostris.

Twelve endocrine cell types immunoreactive for either 5-hydroxytryptamine (5-HT), somatostatin, gastrin, motilin, neurotensin, bovine pancreatic polypeptide (BPP), avian pancreatic polypeptide (APP), pancreatic glucagon, enteroglucagon, glicentin, secretin or cholecystokinin (CCK) were found in gastrointestinal mucosa of Caiman latirostris. Moderate numbers of enteroglucagon-immunoreactive cells, a few 5-HT-, somatostatin- and motilin-immunoreactive cells and rare pancreatic glucagon-immunoreactive cells were found in the fundic stomach. Numerous gastrin-immunoreactive cells and moderate numbers of somatostatin- and motilin-immunoreactive cells were seen in the pyloric stomach. Moderate numbers of 5-HT-, gastrin-, motilin- and enteroglucagon-immunoreactive cells, a few somatostatin-, neurotensin- and BPP-immunoreactive cells, and rare APP-, pancreatic glucagon-, glicentin-, secretin- and CCK-immunoreactive cells were observed in the proximal intestine. Moderate numbers of 5-HT-immunoreactive cells, small to moderate numbers of neurotensin- and enteroglucagon-immunoreactive cells and occasional somatostatin-, motilin- and BPP-immunoreactive cells were seen in the distal intestine. Moderate numbers of neurotensin-immunoreactive cells and a few 5-HT-immunoreactive cells were found also in the cloaca. Cells immunoreactive for gastrin releasing polypeptide, bombesin and gastric inhibitory peptide were not observed in the caiman gastrointestinal epithelium. The differences in endocrine cell types between the caiman and alligator are discussed in terms of their topographic distribution.

Alligators and Crocodiles↗
PubMed1987

Histological and immunohistochemical study on ontogeny of the endocrine cells in the quail gizzard.

The pre- and post-hatching development and differentiation of the endocrine cells in quail gizzard were examined histologically and immunohistochemically. A total of 158 heads (from 5th d of incubation to adult) were used in this study. The formation of gizzard tubular glands began from 11th d of incubation. 8 kinds of endocrine cells, argyrophil cells, and gastrin releasing polypeptide (GRP)-, 5-hydroxytryptamine (5-HT)-, somatostatin-, glucagon-, avian pancreatic polypeptide (APP)-, neurotensin-, and gastrin-immunoreactive cells were detected in the gizzard. These endocrine cells began to appear from 10th d of incubation. Argyrophil cells and GRP-immunoreactive cells in the gizzard were increased with age. Other kinds of immunoreactive cells were found rarely and irregularly, and some of them were found transitory in the embryonic stage.

Animals↗