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Biomedical subjects

J Sudo

Publications and source records attributed to J Sudo.

At least 19 recordsLinked to original sources

[Periodontal disease and implant-supported prostheses].

Periodontal disease is one of the most common dental pathologies which is found in more than 80% of the Japanese adult population. It is also one of the major causes of tooth loss where more than 50% of the tooth are lost due to the periodontal disease. To reconstruct the dental defects, and re-establish the lost functions due to the periodontal disease are very important aspects of the clinical dentistry. Because of the aging society, these services will become even more critical. To lose a tooth not only means a compromised masticatory efficiency, but it has a profound effect on the patient's QOL and ADL. That is why the rehabilitation of the dental function becomes so important. There are two major clinical procedures for the reconstruction of the lost dental functions. They are (1) bridge or partial denture, and (2) implant-supported prostheses. Among other problems, the crown-root ratio of the periodontally involved teeth are less than adequate to serve as an abutment tooth for a bridge, or a clasped tooth for a partial denture. Their prognosis is questionable because of an excessive load over the diseased tooth. Implant-supported prostheses, in contrast, have an excellent long term prognosis because the prosthetic appliances are directly supported by the jaw bone.

English Abstract↗

Assay of ATPase and Na,K-ATPase activity using high-performance liquid chromatographic determination of ADP derived from ATP.

An HPLC assay for determination of ATPase activity was developed and validated. After stopping the enzyme reaction of the enzyme source (rat renal cortical basolateral membranes) with ATP, products derived from ATP were analyzed by two methods; HPLC determination of ADP derived from ATP, and colorimetry of inorganic phosphorus (Pi) released from ATP. This HPLC procedure was precise and linear over the range of protein amount of the enzyme source studied, and the intra-and inter-assay variations were lower than 10%. The values that were obtained by the two methods revealed a significant correlation. Also, even when the samples contained Pi or were contaminated with Pi, this HPLC method allowed determination of ATPase activity. In addition, when ouabain was used as an inhibitor, the HPLC method was found to be applicable for Na,K-ATPase determination. This indicated that this HPLC assay would enable determination of ATPases other than Na,K-ATPase, when other inhibitors are employed instead of ouabain.

Adenosine Diphosphate↗

Transdermal absorption of L-dopa from a new system composed of two separate layers of L-dopa and hydrogel in rats.

To maintain the stability of L-dopa in hydrogel, a new system composed of two separate layers of L-dopa and hydrogel was developed. L-Dopa sheets were made by immersing L-dopa solution into wiper sheets and by lyophilizing them. Examination for stability of L-dopa in the L-dopa sheet revealed that its stability was maintained for at least 12 weeks, providing the sheet was kept at room temperature in a dark box. In a cutaneous absorption study of L-dopa in rats, an L-dopa sheet was attached to the shaved abdominal skin. A hydrogel composed of cutaneous absorption enhancers, water and ethanol, was spread on vinyl tape (hydrogel sheet), and this sheet was placed over the L-dopa sheet. L-Dopa that was administered transdermally effectively penetrated through the skin: The plasma level of L-dopa peaked at 30 min and remained high between 60 and 180 min after the cutaneous application. Our system, composed of two separated layers of L-dopa and hydrogel, enabled the stability of L-dopa to be maintained without losing transdermal absorption of L-dopa.

Administration, Cutaneous↗

Transdermal absorption of L-dopa from hydrogel in rats.

To improve compliance in administration of l-dopa, transdermal absorption of the agent was investigated in rats in vitro employing two-chamber diffusion cells in which the excised rat abdominal skin was mounted, and in vivo using an alcoholic hydrogel containing l-menthol. The in vitro study revealed that in presence of l-menthol (2%, W/W), ethanol (20 and 40%, V/V) accelerated transdermal penetration of l-dopa with an increase of its percentages. The in vivo study showed that when the l-dopa-hydrogel containing 2% l-menthol and 40% ethanol was attached on the skin, plasma levels of l-dopa and norepinephrine increased with the time elapsed; the level of dopamine increased and reached a plateau thereafter; and the level of epinephrine was unchanged. These in vitro and in vivo findings indicated that the hydrogel formulation of l-dopa provides new direction in treating Parkinson's disease.

Administration, Cutaneous↗

Mechanism of nephrotoxicity induced by repeated administration of cadmium chloride in rats.

To explore the mechanism of Cd nephrotoxicity, CdCl2 was subcutaneously injected to rats, at 3 mg Cd/kg body weight once a day, for 8 d. In the liver, Cd bound to metallothioneins (MTs-Cd) rose from d 1 after the initiation of CdCl2 administration, and reached a plateau after the administration ceased. In the plasma, MTs-Cd rose from d 4, peaked on d 8, and gradually fell thereafter. In the kidneys, leucine aminopeptidase (LAP) and N-acetyl beta-D-glucosaminidase (NAG) fell during d 6-20, and Cd bound to cellular membranes (Mem-Cd) rose from d 1 and reached a plateau during d 6-20. The Mem-Cd levels were significantly correlated with the reduction in the LAP and NAG activity; the values of MTs-Cd plus Mem-Cd were almost equivalent to those of total Cd. These findings showed that the hepatic synthesis of MTs-Cd occurred followed by its release into plasma; the extent of renal injury was aggravated as the plasma level of MTs-Cd rose; and a greater part of the renal Cd distributed intracellularly as the MTs-binding form, while the residual Cd distributed as the cellular membrane-binding form. Also, it was suggested that Cd that occurred as the cellular membrane- binding form in the kidneys was involved in manifestation of renal injury.

Acetylglucosaminidase↗

Higher dopamine level in lymph from the cervical lymph trunk than in plasma following intravenous bolus injection of L-dopa in rats.

To clarify the mechanism(s) responsible for nausea and vomiting induced by L-dopa administration, dopamine levels in the plasma and lymph of rats were investigated in the 60-min period following an intravenous bolus of L-dopa (2.5 mg/kg body weight). The dopamine level in plasma from the femoral artery was the highest at 5 min immediately after the L-dopa injection, and was eliminated thereafter. Showing the same tendency as the plasma, the lymph from the thoracic duct showed a maximal increase of dopamine at 0 to 10 min, and a rapid decrease later. In contrast, the dopamine level in the lymph from the cervical lymph trunk increased, peaked at 10 to 20 min, and fell gradually thereafter. The dopamine level in the cervical lymph was higher than that in the thoracic lymph. When these data were kinetically analyzed, the cervical lymph had a larger area under the dopamine concentration-time curve than the thoracic lymph. Both the cervical lymph and the thoracic lymph had longer values of dopamine mean residence time than the plasma. Our findings revealed that when L-dopa was administered with an intravenous bolus, dopamine was higher and remained longer in the cervical lymph than in the rest of the body.

Animals↗

Kinetics of Cd2+ in plasma, liver and kidneys after single intravenous injection of Cd-metallothionein-II.

To explore the kinetics of Cd2+ in the body, rats received a single intravenous injection of CdCl2 or Cd-saturated metallothionein-II at 0.3 mg Cd/kg body weight. Cd2+ in the two agents was biexponentially eliminated from plasma: rapidly in the first 5 min, and gradually later. Compared with CdCl2, Cd-saturated metallothionein-II showed lower Cd2+ concentrations in plasma during the first 30 min; larger values for parameters concerning distribution of Cd2+, its total body clearance and half-life time in the beta phase. Cd2+ uptake in the liver was higher with CdCl2, and, conversely, in the kidneys it was higher with Cd-saturated metallothionein-II. In Cd-saturated metallothionein-II, the renal content of Cd2+ reached a maximum (8 micrograms Cd2+/g tissue) on day 1, gradually decreasing thereafter; there was a higher area under the Cd2+ content-time curve, and a lower mean residence time of Cd2+; the kidneys showed severe necrosis and defluxion of proximal tubular cells at days 1 and 5, although there were regenerative and reversion signs on day 5. These findings suggested that, in the case of Cd-saturated metallothionein-II, Cd2+ being taken into the cells of proximal tubules was excluded predominantly due to cellular death and the resultant defluxion.

Animals↗

Proteinuric potentials of angiotensin II, [des-Asp1]-angiotensin II, and [des-Asp1, des-Arg2]-angiotensin II in rats.

To compare proteinuric potentials among angiotensin II (ANG II) and its fragments, [des-Asp1]-angiotensin II (ANG III) and [des-Asp1, des-Arg2]-angiotensin II (ANG IV), the peptide was intravenously infused for 30 min at doses of 0.015, 0.05, 0.15, 0.45 and 1.45 nmol/kg body weight/min. The infusion of ANG II and ANG III increased the fractional clearance of albumin in a dose-dependent manner: most extensively for ANG II, and moderately for ANG III. In contrast, the infusion of ANG IV hardly showed any proteinuric action, even at the maximal dose of 1.45 nmol/kg body weight/min. These results denoted that the cleaving of the N-terminal aspartic acid1 from ANG II weakened the proteinuric action in the glomeruli, and the further cleaving of the N-terminal arginine from ANG III led to a complete loss of proteinuric action in the glomeruli.

Angiotensin II↗

Clearance study for the estimation of glomerular filtration of Cd following the intravenous bolus of CdCl2 and Cd-saturated metallothionein-II in rats.

A clearance study of Cd was carried out in rats that had received an intravenous bolus of CdCl2 or Cd-saturated metallothionein-II (Cd-MT-II) at 0.3 mg Cd/kg body weight. Urinary concentrations of Cd, and those corrected by the urine-plasma inulin ratio, were higher, by 2 or 3 orders of magnitude, for Cd-MT-II than for CdCl2. Fractional clearance of Cd was 0.0006 to 0.0029 for CdCl2, and 0.130 to 0.487 for Cd-MT-II. These findings denoted that the glomerular filtration of Cd was greater in the Cd-MT-II administration than in CdCl2 administration. This difference in the glomerular filtration of Cd gave a clear explanation for the greater nephrotoxic potential of Cd-MT-II. Also, our data revealed that when Cd was administered as Cd-MT-II, the concentration of Cd was 20 to 70 times higher at the end-point of the renal tubules than at its starting-point. This and the histopathological reports so far strongly suggest that the distally located tubules are highly resistant to intraluminal Cd.

Animals↗

Alterations of metal content in the kidneys of puromycin aminonucleoside-administered rats.

To explore the mechanism responsible for puromycin aminonucleoside induced-nephrotoxicity, metal content was preliminarily investigated in the kidneys of rats that had received a single subcutaneous injection of the agent (80 mg/kg body weight). In the group that received this agent, the renal content of Fe rose on days 5, 10, and 15; that of Cu fell on days 10 and 15; that of Zn rose on day 5; that of Se fell on day 10; there were no changes in Mn throughout the experimental period. Providing that these findings directly involved the renal activities of superoxide dismutases and glutathione peroxidase, the renal reduction of Cu and Se gave proof counter to previous findings of an enzymatic protective system against possible attacks by the oxygen radicals.

Analysis of Variance↗

Interrelations of cadmium contents and histopathological changes in kidneys following single intravenous injection of cadmium-saturated metallothionein II in rats.

An interrelation of Cd-contents with hepato- and nephrotoxicities, and a mechanism for Cd-exclusion from kidneys were investigated in rats that received a single intravenous injection of either CdCl2 or Cd-saturated metallothionein II (Cd-MT-II) with doses of 0.1 and 0.3 mg Cd/kg body weight (b.w.). Between the livers and kidneys, higher uptake of Cd was observed in the liver in terms of CdCl2, and in the kidney in terms of Cd-MT-II. The CdCl2 at the two doses hardly showed any histopathological alterations in the livers and kidneys. The 0.1 mg Cd/kg b.w. of Cd-MT-II showed a slight injury in the kidneys, while hardly in the livers. At Day 1 of the 0.3 mg Cd/kg b.w. of Cd-MT-II, the renal Cd-contents reached the maximal value of 8.22 +/- 0.36 microgram/g wet tissue, and degeneration including necrosis and defluxion of proximal tubular cells were most highly observed. At Day 5 of the 0.3 mg Cd/kg b.w., the renal Cd-contents were lowered to 2.40 +/- 0.24 micrograms/g wet tissue, and fibrosis and regeneration of the proximal tubular cells were remarkably found. These findings strongly suggested that, in the case of administration of Cd-MT-II, the Cd taken into the kidneys was eliminated from there mainly by cellular death of the proximal tubulus and by their resultant defluxion.

Animals↗

Urinary albumin determination by gel-filtration high-performance liquid chromatography.

To determine urinary albumin in a minute amount, a gel-filtration high-performance liquid chromatographic procedure was newly established. When urine of a normal rat was eluted isocratically at 0.6 ml/min by 100 mM Na sulfate in 20 mM Na, K-phosphate (pH 7.4), approximately 6 hrs for complete elution of urinary peak-forming substances was needed. Retention time of albumin was found to be 22.9 min. To shorten the analytic time, 100 mM Na sulfate in 20 mM Na, K-phosphate (pH 7.4) was first used during a 30 min period for separation of albumin. A mixture of acetonitrile/the above solvent = 3/7 (v/v) was then flushed to wash away the peak-forming substances. By this elution mode, the analytic time could be reduced to 3 hrs. When the validity of this procedure was tested, the detection limit of albumin was 0.04 microgram/injection, and a linearity was observed between 0.2 and 50 micrograms/injection. Rats then received single subcutaneous injections of puromycin aminonucleoside, which is a nephrotoxic agent. The plasma albumin concentrations fell at 5, 10 and 15 days after the administration, and the urinary excretions of albumin rose from the 1st day up to the 15th day. The results denoted that our procedure could be a good evaluative tool for nephrotoxicity studies where albuminuria was manifested.

Albumins↗

Thrombocytopenia and leukocytosis induced by single intravenous injections of cadmium-saturated metallothioneins-I and -II in rats.

To comparably investigate hemotoxic potentials of CdCl2, cadmium-saturated metallothioneins-I (Cd-MT-I) and -II (Cd-MT-II), rats received single intravenous injections of one of those dissolved in saline with equivalent concentrations of Cd (0, 0.1, 0.3 and 1.0 mg Cd/kg body weight), and blood for hematological examinations was sampled at 1 and 5 days (Days 1 and 5) after the administrations. The counts of white blood cells showed dose-dependent increments in the 0.3 and 1.0 mg Cd/kg groups in Cd-MT-I and Cd-MT-II at Day 1, and returned to the normal levels at Day 5. The counts of platelets showed dose-dependent decrements in the three-doses groups of Cd-MT-I and Cd-MT-II at Day 1, and did a returning- and further increasing tendency at Day 5. The counts of red blood cells, values of hematocrit, hemoglobin, mean corpuscular volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration, showed only slight and sporadic changes at Days 1 and 5. As to that thrombocytopenia and leukocytosis were dose-dependently brought by Cd-MTs and not by CdCl2, and as to that CdCl2 and Cd-MTs hardly affected erythrocytes regarding their counts, sizes, hemoglobin contents etc., etiological mechanism (s) remains to be explored. However, our findings should be clinically emphasized in relation to Itai-Itai disease and Cd-intoxication.

Animals↗

Application of biological samples treated by wet-digested mineralization to cation-exchange high-performance liquid chromatography with post-column reaction by 4-(2-pyridylazo)-resorcinol.

To quantify metals in biological samples, we tried to find good conditions for wet-digested mineralization of the samples and for separation of metal ions in chromatography. A 500 microliters volume of aliquot was transferred to a glass tube, and was evapolated at 100 degrees C for 2 hours. A 5.5 ml volume of a mixture of concentrated nitric acid-70% perchloric acid (10: 1, v/v) was added and heated, consecutively, at 80 degrees C for 12 hours, at 140 degrees C for 2 hours, at 180 degrees C for 2 hours, and finally at 190 degrees C for 1 hour to evapolate the residual acids. After addition of 500 microliters of 10 mM nitric acid, the metals were extracted by a suspension mixer (32 r.p.m., 1 hour). One hundred microliters of the extracted solution was applied to the chromatographic system: cation-exchange column, TSKgel IC-Cation SW (Tosoh Co.); eluent, 0.35 M lactic acid-0.35 M sodium lactate (pH 3.0); flow rate, 0.7 ml/minute; column temperature, 30 degrees C. After adding a color-forming reagent (100 mg/l 4-(2-pyridylazo)-resorcinol in 40 g/l Na2CO3; flow rate, 0.7 ml/minute) to the effluent, five different metal ions of Cd2+, Co2+, Cu2+, Ni2+ and Zn2+ were detected at 520 nm. The peaks were separated in approximately 25 minutes, and were quantified even at the 1-10 ppb levels. The present procedures were considered to provide simultaneous detection and accurate quantitation of the above five metals in the biological samples.

Animals↗

Lipid peroxidation and generations of oxygen radicals induced by cephaloridine in renal cortical microsomes of rats.

To investigate whether oxygen radicals would be generated by cephaloridine (CER) in the renal cortical microsomes obtained from rats and whether the microsomal lipid peroxidation would be promoted by CER, the microsomes were incubated under a pure oxygen atmosphere in a medium containing the reduced nicotinamide adenine dinucleotide phosphate regenerating system, under various conditions. Generations of superoxide anion and hydrogen peroxide and malondialdehyde formation were all dependent on microsomal protein concentrations, incubation periods and CER concentrations. Scavengers of the microsomal lipid peroxidation induced by CER, (+)-cyanidanol-3, mannitol, sodium benzoate and N-acetyl tryptophan, which are scavengers of hydroxyl free radicals, inhibited the CER-stimulated lipid peroxidation in the microsomes. Histidine, a scavenger of hydroxyl free radicals and singlet oxygen, and alpha-tocopherol, reduced-glutathione and NN'-diphenyl-p-phenylenediamine, the three of which are non-specific antioxidants, also inhibited the CER-stimulated lipid peroxidation in the microsomes. Accordingly, our findings may strongly support that CER generates not only superoxide anions and hydrogen peroxide but also hydroxyl free radicals in the kidney, and these generated oxygen radicals react with the membrane lipids to induce peroxidation and nephrotoxicity.

Animals↗

Protective effects of adrenoceptor-blocking agents on myocardial injury induced by epinephrine in mice.

Employing propranolol as a non-selective beta-blocker, atenolol, acebutolol and metoprolol as selective beta 1-blockers, butoxamine as a selective beta 2-blocker, labetalol as an alpha- and beta-blocker, and phentolamine as an alpha-blocker, we compared the effects of these adrenoceptor-blocking agents to reduce the degree of the myocardial injury induced by epinephrine in mice. Epinephrine in a single dose of 4 mg/kg/day, s.c., daily for 7 days, caused widely extended lesions, necrosis and fibrosis in the myocardial fibers, and degeneration in the residual myocardial fibers. The adrenoceptor-blocking agents in a dose of 10 mg/kg/day, s.c., given 30 minutes prior to epinephrine to each mouse daily for 7 days, had reduced the degree of the myocardial injury induced by epinephrine. The blockers, all, effectively suppressed the injury. Although metoprolol and butoxamine were less effective on the protection of the cardiotoxicity than phentolamine, the other blockers prevented the cardiotoxicity with the same degree as phentolamine did. These findings suggest that not only alpha- but also beta 1- and beta 2-adrenoceptors play critical roles in producing the myocardial injury.

Adrenergic alpha-Antagonists↗

Interrelation of urinary and plasma levels of guanidinoacetic acid with alteration in renal activity of glycine amidinotransferase in acute renal failure rats.

The present study was undertaken to investigate the changes of plasma and urinary levels of guanidinoacetic acid (GAA) in relation to the alteration of renal activity of glycine amidinotransferase (GAT) in the acute stage of renal failure. Rats received cephaloridine at doses of 0 (control), 100 and 1000 mg/kg body weight. The 100 mg/kg group showed rises in the urinary excretion of GAA from the 2nd to the 4th day, but did not show any changes in the other items determined. The urinary excretion of GAA in the 1000 mg/kg group showed a rise on the 1st day, and a fall on the 3rd day. The renal arginine in the group fell from days 1 to 4. The renal activity of GAT in the group fell from day 2, reached the lowest level on day 3, and reverted to the control level after day 5. These results suggest that the rise in the urinary excretion of GAA on the 1st day was ascribable to an inhibitory effect of cephaloridine on renal reabsorption of GAA, and that the fall in its urinary excretion on the 3rd day was ascribable to the suppression in the renal GAA formation system including GAT, arginine and so on.

Acute Kidney Injury↗