Biomedical subjects

A Jikko

Publications and source records attributed to A Jikko.

35 records · Page 2Linked to original sources

PubMed1994

Changes in parathyroid hormone receptors during chondrocyte cytodifferentiation.

The purpose of this study was to investigate the relationship between changes in parathyroid hormone (PTH) receptor levels and chondrocyte maturation during endochondral ossification. Chondrocytes were isolated from the growth plate of rabbit ribs and maintained in the presence of 10% serum in mass cultures. Treatment with PTH-(1-84) and a PTH-(1-34) fragment suppressed the increases in alkaline phosphatase activity and in type X collagen and 1 alpha,25-dihydroxyvitamin D3 receptor levels and abolished 45Ca incorporation into mineral, all of which occurred in parallel untreated cultures in the hypertrophic (terminal) stage. These effects of PTH were observed at low concentrations (10(-10) to 10(-9) M) and within 24-48 h of treatment. PTH-(1-84) and PTH-(1-34) also increased [35S]sulfate incorporation into newly synthesized proteoglycans. In contrast, the middle and carboxyl-terminal fragments of PTH tested had little effect on proteoglycan synthesis or terminal differentiation. The binding of 125I-PTH-(1-34) to cells in the growth plate was greater than that to cells in liver, skin, muscle, brain, or kidney. When the correlation between binding levels and stage of maturation was examined, we found that 125I-PTH-(1-34) binding to its 72-kDa receptor was low in resting and proliferating chondrocytes, increased 10-fold in matrix-forming chondrocytes, and thereafter decreased in hypertrophic chondrocytes both in vitro and in situ. Scatchard analysis revealed that the changes in PTH binding were due to changes in the number, and not in the affinity, of the receptor. The changes in PTH-(1-34) binding paralleled those in [35S]sulfate incorporation into proteoglycans. These findings suggest that stage-dependent increases in PTH/PTH-related peptide receptor levels localize the hormone stimulation of proteoglycan synthesis and inhibition of precocious hypertrophy in the matrix-forming zone of growth plates.

Alkaline Phosphatase↗

PubMed1993

Effects of hyaluronic acid on the release of proteoglycan from the cell matrix in rabbit chondrocyte cultures in the presence and absence of cytokines.

OBJECTIVE: To investigate the effects of hyaluronic acid (HA) on the release of proteoglycan by cultured rabbit chondrocytes. METHODS: Articular cartilage chondrocytes were isolated from the knee joints of New Zealand white rabbits. Proteoglycan synthesis after incubation with HA was determined by measuring 35S-sulfate incorporation. Cells incubated with HA were labeled with 3H-glucosamine and applied to a Sepharose CL-2B column. After incubation of confluent cells with 35S-sulfate and then with HA in various concentrations in the presence or absence of cytokines, proteoglycan release from the cell matrix layer was measured. RESULTS: HA (M(r) 3 x 10(5) to 19 x 10(5)), at 10 micrograms/ml to 1 mg/ml, had little effect on the incorporation of 35S-sulfate or 3H-glucosamine into cartilage matrix proteoglycans, or on the hydrodynamic size of proteoglycan monomers, in rabbit chondrocyte cultures. However, at 10-1,000 micrograms/ml, HA suppressed the release of 35S-proteoglycans from the cell matrix layer into the medium in the presence and absence of interleukin-1, tumor necrosis factor alpha, or basic fibroblast growth factor. CONCLUSION: These results suggest that HA is a potent inhibitor of the displacement of matrix proteoglycan into culture medium.

Animals↗

PubMed1993

Characterization of the mineralization process in cultures of rabbit growth plate chondrocytes.

The present study was undertaken to investigate the mineralization process in chondrocyte cultures. Chondrocytes were isolated from the growth plate of ribs of 4-week-old rabbits. The nature and properties of mineral crystals precipitated in chondrocyte cultures were compared with those of crystals formed in the hypertrophic zone and bone of rabbit rib growth plates in vivo. The chondrocytes were maintained at high density on type II collagen-coated dishes in Eagle's medium, alpha-modification, with 10% fetal bovine serum and 50 micrograms/ml of ascorbic acid. These cells differentiated into hypertrophic cells 10 days after seeding and produced alkaline phosphatase and 1,25-dihydroxyvitamin D3 receptors on Days 30-70 at levels as high as those in the lower hypertrophic zone in vivo. Mineralization was initiated between Days 20 and 30 and advanced progressively throughout the culture period. However, mineralization was suppressed by the addition of parathyroid hormone (2 x 10(-8) M) or by the presence of fibroblasts. Examination by electron microscopy and Fourier transform infrared (FTIR) spectroscopy verified that mineralized nodules formed in vitro were composed of small apatite crystals. Importantly, FTIR spectral features of the apatite crystals (e.g., the prominent PO4 bands at 1125 and 1032 cm-1) were similar to those of cartilage apatites formed in vivo and differed markedly from those of carbonated bone apatites. These results suggest that growth plate chondrocytes cultured on collagen-coated dishes are an appropriate model for studies on cartilage mineralization.

Alkaline Phosphatase↗

PubMed1990

Effects of parathyroid hormone and calcitonin on alkaline phosphatase activity and matrix calcification in rabbit growth-plate chondrocyte cultures.

The effects of PTH and calcitonin (CT) on the expression of mineralization-related phenotypes by chondrocytes were examined. In cultures of pelleted growth-plate chondrocytes. PTH caused 60-90% decreases in alkaline phosphatase activity, the incorporation of 45Ca into insoluble material, and the calcium content during the post-mitotic stage. These effects of PTH were dose-dependent and reversible. In contrast, CT increased alkaline phosphatase activity, 45Ca incorporation into insoluble material, and the calcium content by 1.4- to 1.8-fold. These observations suggest that PTH directly inhibits the expression of the mineralization-related phenotypes by growth-plate chondrocytes, and that CT has the opposite effects.

Alkaline Phosphatase↗

PubMed1989

[A case of mediastinal neurilemmoma diagnosed by X-ray guided needle biopsy].

A 70-year-old female was admitted to our hospital complaining of general lassitude. She had been treated for duodenal ulcer. A routine chest X-ray film at admission showed a large tumorous shadow in the right apical field. A computed tomographic scan revealed that it was a posterior mediastinal tumor containing multiple cystic lesions. After medical treatment for duodenal ulcer, a needle biopsy was performed for histological diagnosis. Under local anesthesia a small skin incision was made in the supraclavicular region to avoid parietal pleura and great vessels and a specimen was obtained by a needle guided by X-ray fluoroscopy. The tumor was diagnosed as neurilemmoma histologically. She was discharged because the complaint subsided. Five months later, however, she was again admitted complaining of righ nuchal pain. Thoracotomy was performed under general anesthesia and the tumor growing from the second intercostal nerve was resected. It was 5 x 4 x 5.5 cm in size, encapsulated and consisted of multiple cystic lesions macroscopically. It was confirmed as Antoni B type neurilemmoma histologically. The nuchal pain subsided and she has been doing well for more than three years after discharge. Recently computed tomography (CT) and ultrasonography (US) have been widely used as a guiding device for needle biopsy. In this case, however, CT guided needle biopsy was not applied for fear of possible complications such as pneumothorax. It was also impossible to perform US guided needle biopsy because the tumor was behind the costal and sternal bones and could not be visualized.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1989

[Analysis of complications following double contrast arthrotomography of the temporomandibular joint].

Temporomandibular joint (TMJ) arthrography is a valuable diagnostic method to evaluate the pathology of soft tissue components of the TMJ. However, arthrography is more or less invasive technique. The aim of this study was to investigate the sort and content of injury following TMJ arthrography. The symptoms before and after the arthrography were compared. In 90 joints that underwent TMJ arthrography, complications such as pain and/or trismus were encountered in 39 joints within one month. Twenty six patients complained of the change of pain conditions including the discomfort. The most common one was the pain on mouth opening. In every joint the pain disappeared within one month without any treatment. There was a high frequency of exacerbated pain in patients with some pain before the arthrography. The change of the degree of maximum opening was recognized in 11 patients. The duration of that condition was somewhat longer than that of pain conditions. In 5 joints with late clicking, 3 developed closed lock. Other complications were swelling, disability of mastication, eczema, hearing impairment and facial paresthesia. All the symptoms disappeared within 1 week without any treatment. From these results it was suggested that TMJ arthrography has low possibility of severe damage to the TMJ although there is some possibility of injury to the bone and soft tissue by arthrographic procedures.

Arthrography↗

PubMed1988

Effects of partial ischemia and reflow on mitochondrial metabolism in rat liver.

To clarify the effects of partial ischemia and reflow on the mitochondrial metabolism of the rat liver, the afferent vessels supplying the left lateral and left half of medial lobes were occluded and then reperfused after given time periods of ischemia (30, 60, 90 and 120 min, groups A, B, C and D, respectively). Samplings were taken at 0, 10 and 60 min after reperfusion. The energy charge levels of ischemic lobes decreased rapidly from 0.85 +/- 0.01 in the sham group to 0.38 +/- 0.11, 0.35 +/- 0.07 and 0.34 +/- 0.06 in groups B, C and D, respectively. The phosphorylative activities of mitochondria isolated from ischemic lobes decreased gradually along with the time of ischemia. The reversal of mitochondrial function and energy charge levels following reperfusion was noted in groups A and B. In nonischemic lobes, the phosphorylation rate (nmol ATP/mg/min) increased from 90 +/- 6 in sham group to 125 +/- 12 and 130 +/- 9; 131 +/- 5 and 130 +/- 6; 123 +/- 6 and 122 +/- 17, and 138 +/- 6 and 138 +/- 13 at 10 and 60 min after reflow in groups A, B, C and D, respectively (p less than 0.05). The energy charge level of nonischemic lobes decreased from 0.85 +/- 0.01 of sham group to 0.80 +/- 0.03 in group D (p less than 0.05). From these results, it is concluded that the transitional zone for the reversal of mitochondria function and energy metabolism following prolonged liver ischemia appears at around 60 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenine Nucleotides↗

PubMed1986

Effect of hepatic artery embolization on the adenylate energy charge level and the redox state of the cirrhotic liver.

Hepatic energy charge ((ATP + 1/2ADP)/(ATP + ADP + AMP)) and arterial blood ketone body ratio (acetoacetate/3-hydroxybutyrate) were measured after hepatic artery embolization in carbon-tetrachloride-induced cirrhotic rats. In normal livers, energy charge slightly decreased at 3 h and returned to normal levels at 6 h. By contrast, in cirrhotic livers, energy charge was drastically decreased at 3 h after embolization and was not completely recovered at 6 h. Blood ketone body ratio, reflecting hepatic mitochondrial redox (NAD+/NADH) state, also decreased at 3 h after embolization in both groups, and its recovery was not observed in cirrhotic group at 6 h.

Adenine Nucleotides↗

PubMed1986

Short-term changes in blood ketone body ratios in the phase immediately after hepatic artery embolization: their clinical significance.

Changes in arterial and hepatic venous blood ketone bodies were investigated following transcatheter hepatic artery embolization (THAE) in patients with hepatocellular carcinoma. Acetoacetate/ beta-hydroxybutyrate ratio (ketone body ratio) in arterial blood was positively correlated with those of hepatic venous blood (r = 0.960, p less than 0.001), which reflects the mitochondrial redox potential in the embolized lobe. Nine cirrhotic patients were classified into three groups according to the changes in arterial blood ketone body ratio following THAE: Type A without decrease to below 0.7; Type B with a transient decrease to below 0.7, followed by its restoration within 5 hours; and Type C with decrease to below 0.7 without recovery within 5 hours. There were no serious complications in Type A and B patients. By contrast, severe sepsis and hepatic failure developed in Type C patients, possibly due to the extended embolization of both lobes. It is suggested that THAE can be successfully performed even in severely cirrhotic patients, as long as the embolized area is restricted to one lobe. In addition, changes in arterial blood ketone body ratios can give early information about the likely consequences of the THAE procedure just performed.

3-Hydroxybutyric Acid↗

PubMed1986

Changes in oxidative phosphorylation, adenylate energy charge, and respiratory components in chloramphenicol-treated regenerating rat liver.

To clarify the functional adaptability of mitochondria in the regenerating liver, the concentrations of respiratory components, hepatic energy charge levels, cytochrome oxidase activity, and phosphorylative activity were studied in mitochondria obtained from regenerating liver of rats treated with chloramphenicol (CAP). In the hepatectomized groups with CAP treatment, a dose-dependent decrease occurred in the concentrations of cytochrome a(+ a3), cytochrome b, cytochrome c + c1, flavoprotein, and pyridine nucleotide. Cytochrome oxidase activity and phosphorylative activity per milligram of mitochondrial protein also decreased dose dependently in CAP-treated hepatectomized groups, with a significant increase in these values per unit of cytochrome a(+ a3). Hepatic energy charge levels significantly decreased in the hepatectomized groups. However, no significant differences were seen among the hepatectomized groups. However, no significant differences were seen among the hepatectomized groups with or without CAP treatment. Our results suggest that hepatic energy charge is maintained at the same relative level by a compensatory enhancement in phosphorylative capacity associated with cytochrome oxidase activity per unit of cytochrome a(+ a3), in spite of a remarkable decrease in the concentrations of respiratory components.

Adaptation, Physiological↗

PubMed1985

Sequential changes in blood concentrations of fuels in relation to arterial blood ketone body ratio after 70% hepatectomy in rabbits.

The changes in arterial blood levels of glucose, free fatty acids, ketone bodies, and amino acids were investigated after 70% hepatectomy in rabbits in relation to the changes in adenylate energy charge of the remnant liver and ketone body ratio of arterial blood. Hepatic energy charge decreased to 0.767 +/- 0.008 within 24 h (p less than 0.001), and arterial blood ketone body ratio decreased to 0.415 +/- 0.041 within 12 h (p less than 0.001). Plasma free fatty acid concentrations increased to about twice the original values within 12 h (p less than 0.01), total amino acid concentrations also doubled within 24 h (p less than 0.01), and blood glucose levels decreased to below 100 mg/dl at 12 and 24 h (p less than 0.05). Afterward, at 96 h postoperatively (p.o.), blood ketone body ratio and energy charge levels were restored to near normal levels with the normalization of blood glucose, plasma free fatty acids, and plasma amino acids. These findings suggest that the decreased energy charge of the remnant liver concomitant with a fall in blood ketone body ratio may be the basis of the sequential changes in the blood concentration of fuels after massive hepatectomy.

Alanine↗

PubMed1985

Relationship of glucose intolerance and indocyanine green clearance to respiratory enzyme levels in human cirrhotic liver.

The relationship of glucose intolerance and indocyanine green clearance to respiratory enzyme levels in liver mitochondria was studied along with standard liver function tests in 40 patients (8 cirrhosis, 19 cirrhosis with hepatoma, 13 non-cirrhotic with hepatoma). There was a negative correlation between cytochrome a(+a3) concentrations and phosphorylative activity per unit of cytochrome a(+a3) (r = -0.75, p less than 0.01), but no correlation between ICG-K and cytochrome a(+a3) concentrations. Cytochrome a(+a3) concentrations in cirrhotic patients with linear oral glucose tolerance pattern, characterized with no return toward normal glucose levels within 120 minutes after an oral glucose load, increased to 1.45 +/- 0.11 (10(-10) mol/mg of protein) compared with 0.90 +/- 0.07 in cirrhotic patients with parabolic OGTT pattern, characterized with a return toward normal glucose levels within 120 minutes (p less than 0.01) (0.82 +/- 0.02 in control patients without liver diseases). The former had high operative mortality regardless of ICG-K value and the latter had virtually uneventful clinical courses. It was suggested that increased cytochrome a(+a3) concentrations and impaired glucose tolerance might be responsible for decreased hepatic functional reserve and poor prognosis in cirrhotics.

ATP Synthetase Complexes↗

PubMed1985

Changes in the reticuloendothelial phagocytic function after partial hepatectomy.

The changes in the phagocytic function of the reticuloendothelial (RE) system after 67% hepatectomy in rats were studied by use of 51Cr-endotoxin as the phagocytable material. The humoral opsonic index was significantly increased to approximately 1.2 to 1.8 (control, 1.0 +/- 0.2, mean +/- SD) until the fourteenth postoperative day. In contrast, the phagocytic index was decreased to 0.068 +/- 0.016 (control, 0.103 +/- 0.015) on the first day, then returned to the normal level on the second day. In this early postoperative period, uptake rates of 51Cr-endotoxin in the liver were remarkably decreased to about 50% to 70% of control, whereas those in the spleen and lung were increased two- to threefold of control. From the third to the fourteenth day, the phagocytic index was significantly increased compared with the preoperative level. During this period, the uptake rates in the liver and spleen were within the normal range. These results suggest that the increases in the opsonic index of 67% hepatectomized rats represent the homeostatic response for maintaining or stimulating RE system phagocytic function, and that high or normal phagocytic index, concomitant with the increase in the opsonic index, implies an enhanced or compensatory stage, respectively. The decrease in the phagocytic index despite the high opsonic index is assumed to represent a compromised stage of the RE system.

Animals↗

PubMed1984

Ketogenesis during sepsis in relation to hepatic energy metabolism.

The concentrations of acetoacetate, beta-hydroxybutyrate, and adenine nucleotides, and the mitochondrial phosphorylative activities, induced by cecal ligation and punctured in the liver of septic rats, were determined. The concentrations of glucose, free fatty acids (FFA), and free amino acids in arterial blood were also studied along with ketone body concentrations. Hepatic energy charge levels decreased from 0.84 to 0.77 at 12h after the induction of sepsis (P less than 0.01) and to 0.60 at 18h (P less than 0.001). Mitochondrial phosphorylative activity was enhanced at 6h (P less than 0.001) and decreased at 18h later. Ketone body concentrations in the liver and the arterial blood decreased concomitant with the decrease in hepatic energy charge. The mitochondrial redox state increased significantly at 12 and 18h after the induction of sepsis (P less than 0.01) concomitant with a marked decrease in the concentrations of ketone bodies (P less than 0.01). Blood glucose levels remained within normal limits except for a transient increase at 6h, but plasma FFA levels decreased (P less than 0.01). The plasma concentrations of aromatic amino acids (P less than 0.001), proline, and alanine (P less than 0.05) increased slightly at 18h. It is suggested that the ketogenic capacity of the liver is inhibited during sepsis, but that the liver maintains gluconeogenesis at relatively normal levels until a more advanced stage of sepsis.

Adenine Nucleotides↗

PubMed1984

Adenylate energy charge and cytochrome a (+a3) in the cirrhotic rat liver.

In the cirrhotic rat liver induced by phenobarbitone and carbon tetrachloride, adenylate energy charge, mitochondrial oxidative phosphorylation, and respiratory enzyme concentrations were studied along with serum albumin concentrations. Cytochrome a (+a3) concentrations of the liver increased with the severity of cirrhosis and were negatively correlated with the ATP-synthesizing ability per unit of cytochrome a (+a3). These changes were associated with the decrease in hepatic energy charge. Such decreased energy charge may be responsible for the decreased serum albumin level in the cirrhotic rat. It is suggested that such falls in hepatic energy charge may be one of the most important factors contributing to the decreased functional reserve of cirrhotic patients.

Adenosine Diphosphate↗

PubMedDate not supplied

Biological significance of enhanced mitochondrial membrane potential in regenerating liver.

Liver mitochondrial membrane potential was assessed during regeneration following partial hepatectomy in rabbits. Absorbance change of safranine O per milligram of mitochondrial protein was used to evaluate mitochondrial membrane potential. Absorbance change was calibrated to the membrane potential in millivolts produced by valinomycin-induced potassium diffusion potential. At 24 hr after hepatectomy, absorbance change of safranine O per milligram of mitochondrial protein increased from 15.0 +/- 2.2 X 10(-3) to 37.4 +/- 3.3 X 10(-3) per mg (p less than 0.005). This represents a mitochondrial membrane potential increase from 77.0 +/- 4.6 to 124.4 +/- 6.7 mV. Phosphorylative activity increased from 59.9 +/- 5.0 to 106.1 +/- 7.4 nmoles ATP synthesized per mg per min (p less than 0.005). The enhancement of phosphorylative activity was closely linked to the elevation in liver mitochondrial membrane potential (r = 0.77, p less than 0.005). We suggest that elevation of mitochondrial membrane potential, coupled with enhanced oxidative and phosphorylative activities, plays an important role in the regeneration process following hepatectomy.

Adenosine Triphosphate↗

PubMedDate not supplied

Differences in the biological effects of in vitro irradiation by 65 MeV protons and 137cesium gamma-rays.

Using the irradiation system constructed for research in radiation biology, we have investigated the differences in the biological effects of in vitro irradiation by 65 MeV protons and by 137Cs gamma-rays. Survival curves were generated using V79 cells. The effects on biological parameters (SF2, RBE) of protons were greater than gamma-rays. Furthermore, 3H-thymidine incorporation in KOSC-3 cells, which display the p53 gene mutation, was inhibited by protons much more than by gamma-rays. On the other hand, in bleomycin-sensitive SCCKN cells, 3H-thymidine incorporation decreased more than in bleomycin-resistant SCCTF cells, however, both were inhibited by protons much more than by gamma-rays. In this study, the biological parameters and 3H-thymidine incorporation caused by 65 MeV protons were more severe than those caused by 137Cs gamma-rays.

Animals↗