Biomedical subjects

T Hiraga

Publications and source records attributed to T Hiraga.

At least 55 records · Page 3Linked to original sources

PubMed1996

Inositol 1,4,5-trisphosphate- and caffeine-sensitive Ca(2+)-storing organelle in bovine adrenal chromaffin cells.

The uptake and release properties of Ca2+ by several subcellular fractions of the bovine adrenal medulla were investigated. Investigation by the 45Ca2+ tracer method showed that permeabilized cells and the fractions of mitochondria (MT) and microsomes (MC) caused ATP-dependent Ca2+ uptake in a Ca2+ concentration-dependent manner (pCa 8-4), whereas permeabilized cells and the fractions of secretory granules (SG) were able to accumulate a significant amount of Ca2+ even in the absence of ATP, which was completed by the addition of hexokinase and glucose. In these organelle fractions, Ca2+ uptake in the presence of ATP at pCa 7 and pCa 5.8 was well-correlated with the activity of the NADPH cytochrome c reductase (marker enzyme for the endoplasmic reticulum) and cytochrome c oxidase (marker enzyme for mitochondria), respectively. As detected by Fura-2 ratiometry, both inositol 1,4,5-trisphosphate (IP3) and caffeine caused concentration-dependent Ca2+ releases from permeabilized cells and MC, but not from MT and SG. In an ATP-depleted condition, homogenates still took up a significant amount of Ca2+ but was not able to respond to IP3 and caffeine. These results suggest that the endoplasmic reticulum is a major Ca(2+)-storing organelle, which releases Ca2+ in response to IP3 and caffeine in bovine adrenal chromaffin cells.

Adrenal Glands↗

PubMed1996

Immunohistochemical analysis of the endocrine cells in the pancreatic islets of cattle.

The distribution of endocrine cells and the areas of islets in the bovine pancreas were investigated by immunohistochemical methods. The islets in the A-region, which consisted of the left lobe, the ventral portion of the body, and the ventral and distal portions of the right lobe, contained a central core of insulin-containing (B-) cells surrounded by glucagon containing (A-) cells, a few somatostatin-containing (D-) cells and sporadic pancreatic polypeptide-containing (PP-) cells. The islets in the B-region, which consisted of the uncinate process, and the dorsal and proximal portions of the body and the right lobe, contained a central mass of B-cells, and peripheral cells which were predominantly PP-cells with a few D-cells but no A-cells. The areas of islets in the B-region were small as compared with those in the A-region. From these findings it is suggested that A- and PP-cells have a complementary relationship to one another. In view of this hypothesis, two types of islet, A-cell-rich and PP-cell-rich islets, were identified. The A-region contained A-cell-rich islets derived from the dorsal pancreatic primordium, while the B-region contained PP-cell-rich islets that originated from the ventral primordium. In the bovine pancreas, the areas containing PP-cell-rich islets are greater than those in previously examined species.

Animals↗

PubMed1995

Bone resorption induced by a metastatic human melanoma cell line.

Bone resorption resulting from the metastatic human melanoma cell line (A375) was investigated morphologically using an experimental model of bone metastases in nude mice. An injection of A375 (1 x 10(5)) in the left ventricle produced multiple osteolytic lesions. Many TRAPase-positive multinucleated cells, identified by EM as osteoclasts, were observed on the bone surface at the site of metastases. The findings suggest that bone resorption was caused by osteoclasts developed in the presence of tumor cells. Even where tumor cells were juxtaposed to bone surface, small and flat TRAPase-positive cells were shown to exist on the bone surface. Thus, bone resorption was mainly associated with the occurrence of osteoclasts. A large number of osteoclast progenitor cells were also observed adjacent to tumor cells and/or stromal cells located apart from bone, indicating possible participation of tumor cells and/or stromal cells in the differentiation of osteoclasts. Ultrastructurally, stromal cells and/or extracellular matrices were present between tumor cells and osteoclast progenitor cells. Immunohistochemical observation clarified the localization of heparan sulfate proteoglycan (HSPG) and fibronectin (FN) around osteoclast progenitor cells. These findings suggest that they play an important role in providing a microenvironment favorable for osteoclast differentiation and activation. The immunohistochemical localization of IL-6, PGE2, and TGF-alpha also indicates that they are involved in osteoclast differentiation and activation. In conclusion, bone resorption at the metastatic sites of A375 is mediated via osteoclasts and A375 cells may be involved in the differentiation and activation of osteoclasts in association with stromal cells, extracellular matrices (HSPG, FN) and osteotropic cytokines (IL-6, PGE2, TGF-alpha).

Acid Phosphatase↗

PubMed1995

Malignant schwannoma arising in patients with von Recklinghausen's disease: report of two cases and the comparison of mast cells between benign and malignant portions.

We described two cases of malignant schwannoma arising in patients with von Recklinghausen's disease and examined the mast cells infiltrated into histologic sections. One of the two cases histologically revealed apparent mast cell infiltration in some areas of malignant schwannoma as well as in the benign neurofibroma. The malignant lesion demonstrated significantly increased percentages of degranulated mast cells over the benign lesion using FITC-avidin staining. In an electron microscopic study, mast cells in the malignant lesion displayed empty granules, piecemeal degranulation, and canaliculi structures suggesting activation. These findings were not observed in the benign lesion. The other patient histologically showed no mast cells in the malignant lesion, although the benign neurofibroma in the patient disclosed numerous mast cells. The first patient had neither recurrence nor distant metastasis. On the other hand, the second patient without mast cells in the histology had multiple distant metastases.

Cell Count↗

PubMed1995

Fine structure of podocytes in the bovine renal corpuscle.

Thick primary processes issued from the hemispherical or plate-like cell bodies of podocytes in bovine renal corpuscles. These processes branched into secondary and tertiary ones, but no fine pedicels were observed on the outer surface of the podocytes by scanning electron microscopy, because each primary process closely interdigitated with those of adjacent cells. Many pedicels, however, were observed under the processes by using the freeze-fractograph and a transmission electron microscope.

Aging↗

PubMed1995

Microvascular changes in the bovine corpus luteum during pregnancy.

The microvasculature of bovine corpora lutea during pregnancy was studied by scanning electron microscopy using corrosion casts. Only one spiral arteriole branched directly from the ovarian artery entered the blood vascular bed of the pregnant corpora lutea. The bed consisted of numerous lobular sinusoidal capillary plexuses during pregnancy, and were characteristic to the microvasculature of a large corpus luteum. At the late stage of pregnancy, arteriovenous anastomoses were situated within the lobular sinusoidal capillary plexus composed of thin sinusoidal capillaries. These anastomoses may induce a decrease in blood flow to the lobular sinusoidal capillary plexus, suggesting that they may have an important role to induce the initial degeneration of the bovine pregnant corpora lutea.

Animals↗

PubMed1995

Microvascular changes during the development of follicles in bovine ovaries: a study of corrosion casts by scanning electron microscopy.

Microvascular changes during the development of follicles in bovine ovaries were studied by scanning electron microscopy of corrosion casts. A clear vascular plexus of ovarian follicles appeared at the stage when secondary follicles were 200-400 microns in diameter. The plexus consisted initially of a thin, roughly structured and single-layered capillary network. During follicular development, the microvascular architecture of antral follicles was arranged as two independent vascular plexuses. The inner plexus, which received a spiral arteriole, consisted of a dense sinusoidal capillary network with an arterial and a venous layer; it functioned as an independent microcirculatory unit. The inner plexus developed from the capillary plexus of the theca interna of the secondary follicles. The outer plexus, which anastomosed with several stromal capillaries, consisted of a thin, coarse and basket-like capillary plexus. The outer plexus was formed from the stromal capillary plexus as a consequence of the rapid enlargement of developing antral follicles.

Animals↗

PubMed1995

Prospective study of lipoprotein(a) as a risk factor for atherosclerotic cardiovascular disease in patients with diabetes.

OBJECTIVE: To assess whether lipoprotein(a) [Lp(a)] is a risk factor for atherosclerotic cardiovascular disease in diabetes. RESEARCH DESIGN AND METHODS: We studied 221 patients with non-insulin-dependent diabetes mellitus (NIDDM) without diabetic complications who were followed for 2.2-3.1 years. Their serum Lp(a) levels were semiquantified by a rapid electrophoretic method that accurately discriminates high from low serum Lp(a) at the 20 mg/dl level. RESULTS: Seven of 105 diabetic patients with a high serum Lp(a) experienced a clinical event related to atherosclerotic cardiovascular disease. This incidence was significantly higher than that of the 110 diabetic patients with a low serum Lp(a). The logistic regression analysis revealed that Lp(a) was an independent risk factor for the event. CONCLUSIONS: Lp(a) is a significant risk factor for atherosclerotic cardiovascular disease in NIDDM.

Adult↗

PubMed1994

Characteristics of porcine coronary artery endothelial cells in culture: comparison with aortic endothelium.

In the present study we compared the characteristics of porcine coronary artery endothelial cells in culture with the characteristics of aortic endothelium. Morphologically, coronary artery endothelial cells were larger than aortic endothelial cells. Under basal culture conditions, both coronary artery and aortic endothelial cells secreted significant amounts of prostacyclin and endothelin-1. The outstanding findings is that coronary artery endothelial cells secreted larger amounts of endothelin-1 than aortic endothelial cells. Immunofluorescence staining revealed that individual endothelial cells synthesize both substances. This comparative study provides important evidence indicating that the characteristics of coronary artery endothelial cells differ from those of aortic endothelial cells.

Animals↗

PubMed1994

Electrospray ionization mass spectrometry of pyridylaminated oligosaccharide derivatives: sensitivity and in-source fragmentation.

Oligosaccharide chains fluorescence-labelled at their reducing end with 2-aminopyridine were analysed by electrospray ionization mass spectrometry (ESIMS). Protonated molecules of complex type oligosaccharides were detectable at a level of 1 pmol. Fragmentation at the glycosidic bonds occurred in the electrospray ion source when the voltage between the capillary nozzle and the first skimmer was elevated, referred to as "in-source fragmentation". Most fragment ions observed had retained the pyridylaminated (PA) site of the molecule and gave significant information on the saccharide sequence. In conjunction with the accumulating data of reversed-phase chromatography of PA oligosaccharides, ESIMS of PA oligosaccharide will be useful as a sensitive method in the structural study of oligosaccharides from various biological sources.

Carbohydrate Sequence↗

PubMed1994

Congenital defects in the llama.

When faced with the question of what you should do as a veterinary practitioner, when presented with a congenital defect in a llama, one answer is to seek qualified help from your state veterinary diagnostic laboratory. But most importantly, encourage the owners of such animals to report the defect to their llama association, including pedigree information. The better we understand the pathogenesis of such defects, the better we will be able to control their incidence.

Animals↗

PubMed1994

Ultracytochemistry of glycoconjugates in pig duodenal gland.

To elucidate the ultrastructure, glycoprotein profile and site of glycosylation of glandular cells in relation to the functional polarity of the organelles, swine duodenal tissue was embedded in glycol methacrylate and subsequently stained for periodic acid thiocarbohydrazide silver proteinate (PA-TCH-SP), high iron diamine (HID)-TCH-SP, low iron diamine (LID)-TCH-SP, ninhydrin T-TCH-SP and five peroxidase-labeled lectins. The secretory granules in the duodenal gland cells were electron lucent with a 200 nm to 500 nm electrondense core. Glycoconjugates were confined to the secretory granules and elements of the Golgi complex. Protein activity was located only in the electron dense core. Achivementestic staining pattern for Concanavalin A (Con A), peanut agglutinin (PNA), Ulex europaeus agglutinin-I (UEA-I), wheat germ agglutinin (WGA) and soybean agglutinin (SBA) was observed in stained secretory granules and the Golgi apparatus. A few cis cisternae were stained with SBA and UEA-I. Trans cisternae were stained with WGA and PNA. Con A reacted with seromucous granules and rough endoplasmic reticulum. These observational findings suggest that these are seromucous cells. The Golgi apparatus is the site of glycosylation and can be divided into two distinct compartments.

Animals↗

PubMed1994

Two distinct types of reticular cells in the pig sheathed artery.

The morphology of reticular cells of the sheathed arteries, in the red pulp of pig spleen, was studied by using transmission electron microscopy; and their histochemical reactivity with periodic acid-thiocarbohydrazide-silver proteinate (PA-TCH-SP). The phagocytic ability was evaluated by injecting colloidal carbon into the splenic artery. Reticular cells of the sheathed arteries were classified as type I and type II cells. Type I cells have a nucleus with scanty chromatin, and the cytoplasm reacts positively to PA-TCH-SP. The PA-TCH-SP-positive granules are considered to be subunits of beta-glycogen particles based on their morphological features. Type II cells have a nucleus with abundant chromatin and are not stained by PA-TCH-SP. Both types of reticular cells are connected with reticular fibers. Results of the colloidal carbon injection showed that type I reticular cells did not ingest carbon particles during the time frame of the experiment, whereas type II reticular cells are phagocytic and ingested carbon.

Animals↗

PubMed1994

Scanning electron microscopical observation of the intramitochondrial body in the bovine corpus luteum during pregnancy and after parturition.

Large luteal cells of the bovine pregnant luteum can be characterized as steroid-producing cells. Mitochondria of these cells contained intramitochondrial bodies (IMB). The three-dimensional structure of the IMB and the degenerative process of luteal cells were as follows: 1) The IMBs were globular or oval, 0.1 to 1.5 microns in diameter. Their outer surfaces were coarse but their cut surfaces were uniform. Their outer surfaces changed from rough to smooth during pregnancy. 2) At the late stage of pregnancy, the large luteal cells lost their cytoplasmic processes, showing the first sign of degeneration at the cell level in such a way that their mitochondrial cristae transformed from tubular to laminar, and that they contained accumulated lipid droplets. 3) After parturition, the IMBs came out from degenerating large luteal cells, and were conveyed by lymphatic capillaries.

Animals↗

PubMed1994

[Glycosylated lipoprotein].

Diabetes is frequently associated with cardiovascular diseases (coronary heart disease, cerebrovascular disease, peripheral vascular disease), and several risk factors have been proposed. Recent studies have strengthened the importance of chronic hyperglycemia because this modifies a variety of circulating substances including lipoproteins, and the glycosylated ones can be involved in the process of accelerating atherosclerosis. In this review, previous studies indicating the significance of glycosylated lipoproteins in the progression of atherosclerosis were overviewed. We also discussed AGE (advanced glycation end products) which may play an important role of atherogenesis in diabetes.

Arteriosclerosis↗

PubMed1993

Reduced numbers and intense anti-ubiquitin immunostaining of bovine motor neurons affected with spinal muscular atrophy.

Motor neurons in the spinal cord affected with bovine spinal muscular atrophy (SMA) were investigated immunohistochemically using antibodies against bovine ubiquitin. Anti-ubiquitin immunostained many chromatolytic and swollen degenerating motor neurons in the ventral horn of the SMA-affected spinal cord. The most severely swollen cells showed a lightly-stained center and a strongly-stained periphery after immunostaining. However, there were many dark, shrunken neurons in a more advanced stage that showed a completely negative reaction when immunostained. Motor neuron counts differed significantly between SMA-affected and normal animals at the lumbar intumescence and at the fourth lumbar neuromere, but not at the brachial intumescence or the second cervical level.

Animals↗

PubMed1993

Serum lipoprotein(a) levels differ in different phenotypes of primary hyperlipoproteinemia.

Previous studies have indicated that serum lipoprotein(a) [Lp(a)] levels are mostly under genetic control. We have attempted to determine whether serum Lp(a) levels differ in different phenotypes of primary hyperlipoproteinemia (HL). A total of 129 subjects with HL (three with type I, 43 with familial hypercholesterolemia [FH], 17 with type IIa [non-FH], 11 with type IIb, six with type III [E2/2], 44 with type IV, and five with type V) and 18 normolipidemic controls were included in the study. Thirty-two FH subjects were being treated with hypolipidemic agents, but none of the other subjects were receiving any medication. Fasting blood samples were collected for determination of both serum lipid and Lp(a) levels. Lp(a) level was measured by enzyme-linked immunosorbent assay. The 18 controls had serum Lp(a) concentrations of 18.0 +/- 14.5 mg/dL (mean +/- SD), and four of them had high serum Lp(a) levels (> or = 25 mg/dL). Serum Lp(a) concentrations in FH subjects tended to be higher than in the controls (30.5 +/- 25.0 mg/dL), and the incidence of high Lp(a) levels in FH subjects was significantly higher than in the controls (51% v 22%, P < .01). There was no difference between serum Lp(a) levels of FH subjects depending on whether they were receiving medication. In contrast, most of the subjects with selective hypertriglyceridemia had very low serum Lp(a) levels (1.5 +/- 0.7, 8.1 +/- 8.3, and 3.5 +/- 5.3 mg/dL in type I, IV, and V, respectively; P < .01 v controls).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1993

Congenital defects of the bovine central nervous system.

What should you do if you observe a defective calf in a herd? Our suggestion is to seek qualified help to examine and diagnose the condition. Parentage should be verified by blood typing. But, most important, you can keep cattle genetically clean by having your clients report all defects in calves to their breed association and artificial insemination centers.

Animals↗