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Biomedical subjects

J Ueda

Publications and source records attributed to J Ueda.

At least 109 records · Page 6Linked to original sources
PubMed1993

Effect of intravenous contrast media on proximal and distal tubular hydrostatic pressure in the rat kidney.

The effect of i.v. injection of contrast media (CM, 1,600 mg I/kg b.w.) on proximal and distal tubular hydrostatic pressure (PTHP, DTHP) in the rat was investigated using a micropuncture technique. The PTHP and DTHP after injection of diatrizoate, iohexol, ioxaglate, or mannitol returned to control values within approximately 20 min. However, following iotrolan injection PTHP was still elevated above control levels after 35 min while DTHP remained elevated throughout the experiment (50 min). Iotrolan has a lower osmotic potential than the other CM when given in equivalent iodine doses. The concentration of iotrolan may thus increase more along the tubules than the other CM and consequently lead to a higher viscosity of urine, resulting in increases in PTHP and DTHP. The high intratubular pressure induced by iotrolan may explain our previous findings of reduced single nephron glomerular filtration rate caused by this CM.

Animals↗
PubMed1992

The coordination of copper(II) to 1-hydroxy-4-(glycyl-histidyl-lysine)-anthraquinone; a synthetic model of anthraquinone anti-cancer drugs.

Results are reported of a pH-metric and spectroscopic (CD and ESR) study of the complexes formed between the pseudo-peptide 1-hydroxy-4-(Gly-His-Lys)-anthraquinone (Q-GHK) since, when complexed to copper ions, Q-GHK has been shown to be very effective in promoting the formation of free radicals and inducing DNA cleavage. Q-GHK forms very stable complexes with copper, the major species being bonded to three nitrogen donors in the coordination plane: an imidazole-N of the His residue and the peptide nitrogens of the Gly and His residues. This species is probably stabilized through bonding of the fourth planar coordination site of Cu(II) to the 9-anthraquinone oxygen. At high Q-GHK:copper ratios a second Q-GHK molecule is coordinated through its imidazole-N donor.

Anthraquinones↗
PubMed1992

A prolongation of hepatic vascular exclusion by in situ hypothermic perfusion in dogs.

In situ hypothermic hepatic perfusion was performed in dogs to explore whether the time limit of hepatic vascular exclusion could be prolonged. During hepatic vascular exclusion, hepatic hypothermic perfusion was performed via portal vein using various perfusates under active bypass from the portal vein and infrahepatic inferior vena cava area to the superior vena cava system. Dogs receiving hepatic hypothermic perfusion for 1 hour died when given Ringer's solution but survived more than 7 days when given Euro-Collins' and University of Wisconsin solutions. Although dogs tolerated 2 hours of hepatic hypothermic perfusion when give University of Wisconsin solution, all dogs died by 2 hours of hepatic hypothermic perfusion when given Euro-Collins' solution. The hepatic energy charge and arterial ketone body ratio of dogs that died were significantly lower than for those that survived. This suggests that the regimen of hepatic hypothermic perfusion with University of Wisconsin solution is able to maintain the energy metabolism of the liver under hepatic vascular exclusion for prolonged periods, hence, its possible clinical application.

Adenosine↗
PubMed1992

[Determination of sennoside A in oriental pharmaceutical decoctions containing Rhei Rhizoma by ion-pair high-performance liquid chromatography].

A simple method using ion-pair high-performance liquid chromatography was established for the rapid and precise determination of sennoside A in oriental pharmaceutical decoctions containing Rhei Rhizoma. This method was compared with other two methods, i.e. ion-suppression and phosphate buffer methods. Sennoside A was eluted without interference in this ion-pair method, while the determination of sennoside A was interfered by co-existing components in the other two methods.

Anthraquinones↗
PubMed1992

Influence of contrast media on single nephron glomerular filtration rate in rat kidney. A comparison between diatrizoate, iohexol, ioxaglate, and iotrolan.

The effects of slow (10 min) i.v. infusions of contrast media (CM, 1,600 mg I/kg b.w.) on single nephron glomerular filtration rate (SNGFR) in the rat kidney were investigated using a micropuncture technique. Diatrizoate, iohexol, or ioxaglate did not change SNGFR, although a tendency towards a transient suppression was seen during the infusion phase. Iotrolan infusion, however, decreased SNGFR (p < 0.05) and the value still remained below the control value 25 min after the start of infusion. Iotrolan is a nonionic dimeric CM and has a lower osmotic effect in the tubules than the ionic dimeric CM and the monomeric CM when given in iodine equivalent doses. These characteristics of iotrolan have probably some influence on the depression of SNGFR after iotrolan injection.

Animals↗
PubMed1991

Hepatic vascular exclusion as a model for complete and stable hepatic ischemia in dogs.

In order to confirm a complete ischemia model, 1-hour warm hepatic ischemia by hepatic vascular exclusion (HVE) was studied in dogs, in comparison with that by inflow occlusion (IOC) only. The splanchnic venous bed and/or infrahepatic inferior vena cava were decompressed by a centripetal pump-driven venovenous bypass. Indocyanine green retention test revealed no hepatic blood flow in the HVE model during ischemia, while hepatic blood perfusion was still present in the IOC model. All 5 of the IOC dogs survived more than 7 days after revascularization, while 4 of the 5 HVE dogs died within 9 h. After the induction of hepatic ischemia, lactate increased in both HVE and IOC dogs. After revascularization, transaminases and guanase were elevated, the arterial ketone body ratio (acetoacetate/3-hydroxybutyrate) decreased and the serum lactate accumulated more in HVE dogs than in IOC dogs. The hepatic redox state of IOC dogs was significantly decreased by additional clamping of the inferior vena cava. It is concluded that the HVE model with a pump-driven active bypass provides complete and stable hepatic ischemia, resulting in greater deterioration of hepatic cellular functions; hence it is more suitable as a model of complete hepatic ischemia than the IOC one.

Animals↗
PubMed1990

Evaluation of temporary portal vein arterialization: the minimum arterialized blood flow for maintaining liver viability.

The effect of temporary portal vein arterialization (PVA) on hepatic energy metabolism was investigated by changes in the arterial blood ketone body ratio (KBR) and hepatic energy charge (EC) level in 17 dogs. The KBR decreased markedly after clamping the hepatic hilar vessels combining mesocaval shunt and remained at a low level throughout hepatic ischemia. After PVA, the KBR was rapidly restored and maintained at sufficient levels. EC at 60 min after arterialization also recovered to the preclamping level. By reducing the arterial shunt flow, the critical point of arterialized blood flow for maintaining the KBR at high levels was assessed to be about 10% of the total hepatic blood flow (THBF). These findings demonstrate that temporary PVA is an effective method for maintaining the functional capacity of the liver, and that the minimum arterialized blood flow needed to preserve liver viability is only about 10% of the total hepatic blood flow.

3-Hydroxybutyric Acid↗
PubMed1990

Computed tomography evaluation of high-density bile in the gallbladder.

On computed tomograms obtained during a seven-year period, 27 patients were found to have high-density bile in the gallbladder. Serial computed tomography (CT) examinations showed that gradual narrowing of common bile duct is a causative factor. This has not been reported previously. The density of the bile in the gallbladder of patients with such obstruction was almost equal to that of normal liver on CT. In some of the patients in whom obstruction of the cystic duct was the factor of high-density bile and continued for a long time, the density of the bile decreased and hydrops developed.

Bile↗
PubMed1990

Influence of verapamil on regional renal blood flow: a study using multichannel laser-Doppler flowmetry.

In anaesthetized male Sprague-Dawley rats the influence of the calcium entry blocker verapamil (2.4 mg h-1 kg-1, i.v.) on renal superficial cortical (CO) and outer medullary (OM) blood flow was investigated with the aim of elucidating further the intrarenal heterogeneity in vasoreactivity. The blood flow of the two regions was monitored simultaneously with a laser-Doppler flowmeter, using fibre probes with an outer diameter of 0.75 mm. One probe was directed towards the cortex and a second probe was inserted through the cortex and positioned in the outer medulla, measuring the flow within a hemisphere with a depth of 0.5-1.0 mm. The OM probe position was verified by dissecting the kidneys after each experiment. Insertion of the OM probe did not affect whole-kidney glomerular filtration rate, renal plasma flow or electrolyte excretion. Thirty minutes of verapamil infusion increased OM blood flow by 26%, but did not change CO blood flow (-1%). In spite of the increase in OM blood flow, the urine osmolality remained unaltered. Sodium excretion increased by 39%, while potassium excretion was unchanged. Mean arterial blood pressure decreased by 13%. In conclusion, this study has further supported the suggestion that the vasoreactivity is higher in the juxtamedullary than in the superficial cortical vasculature. The heterogeneity of the response is most probably due to the previously documented pressure drop along the interlobular arteries, which will create different haemodynamic conditions for the juxtamedullary and superficial afferent arterioles.

Animals↗
PubMed1990

Influence of dopamine on the liver assessed by changes in arterial ketone body ratio in brain-dead dogs.

The influence of dopamine on liver metabolism in the state of brain death was assessed by measuring arterial ketone body ratio (AKBR) in dogs. Mean arterial blood pressure (MABP) was significantly decreased, from 137.4 +/- 3.7 to 64.7 +/- 2.8 mm Hg, 1 hour after completion of brain death (p less than 0.01). In the control group AKBR was maintained at the near control value of 1.07 thereafter, concomitant with a significant decrease in serum lactate levels, despite marked hypotension (p less than 0.05). Dopamine infusion at rates of 5 and 10 micrograms/kg/min sustained both AKBR and MABP at near control values. In contrast, dopamine given at doses greater than 15 micrograms/kg/min caused a significant reduction of AKBR, to less than 0.66 +/- 0.12 (p less than 0.01), although MABP was restored to near-normal levels. In addition, serum levels of alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase were significantly elevated, reflecting liver cell injury. It is suggested that the liver is primarily tolerant to hypotension in the state of brain death and that dopamine administered at a rate of 15 micrograms/kg/min or more impairs liver metabolism by reducing the redox state (free nicotinamide-adenine dinucleotide/reduced nicotinamide-adenine dinucleotide) of liver mitochondria.

Animals↗
PubMed1989

Hepatic tolerance to hypotension as assessed by the changes in arterial ketone body ratio in the state of brain death.

Hepatic tolerance to hypotension was assessed by changes in arterial ketone body ratio (KBR) and hepatic energy charge levels in experimental brain death induced by epidural ballooning in dogs, and compared with the hemorrhagic shock model. Systolic arterial blood pressure was significantly decreased from 182 mmHg to 67 mmHg after completion of brain death (P less than 0.01), but KBR was maintained at near the control value of 1.098 +/- 0.051 in spite of marked hypotension. Hepatic energy charge was 0.846 +/- 0.016 and remained at normal level. No significant changes were observed in lactate level, total bilirubin, SGPT, and LDH. SGOT was slightly elevated but was still within normal limits (P less than 0.05). Light microscopic examination revealed no apparent ischemic change in the centrilobular region under hematoxylin and eosin staining. By contrast, KBR decreased from 0.975 +/- 0.054 to 0.273 +/- 0.060 following hypotension in the Wiggers' shock model (P less than 0.01). Lactate levels were gradually elevated significantly (P less than 0.05), but no significant increases were observed in total bilirubin, SGOT, SGPT, and LDH. It is suggested that the hepatic energy status is well maintained in the state of brain death, in which state the liver has high tolerance to marked hypotension until shortly before stoppage of the heart.

Animals↗
PubMed1989

Orthotopic partial liver transplantation in dogs can be performed without cold perfusion of the donor liver. Evaluation of its feasibility in terms of energy metabolism.

To investigate the feasibility of obtaining grafts from living, genetically related adult donors without any complicated harvesting techniques, orthotopic partial liver transplantation (PLT) without cold perfusion of the donor graft was evaluated in beagles by assessing the graft viability using ketone body ratio (KBR). Ten PLT were performed under venovenous bypass. The left half of the donor liver was transected in situ followed by systemic heparinization, and immediately implanted with care taken to leave the recipient's inferior vena cava intact, and to maintain the normothermic state without cold perfusion. Four of ten dogs survived for 5 days or longer (longest survival was 9 days) and died of other causes than graft dysfunction. Four others died of thromboembolitic episode, accidental bleeding or technical failure. Two dogs died of graft dysfunction. The changes in KBR in 5 dogs without fatal complications after transplantation were maintained within normal range thereafter. These results suggest that the PLT without cold perfusion of donor graft is possible from the viewpoint of energy metabolism.

Animals↗
PubMed1988

Graft transection and warm perfusion in situ in canine partial orthotopic liver transplantation.

Liver transplantation is now proven therapy for various forms of end-stage liver disease in children; however, the problem of donor liver shortage remains. To investigate the feasibility of graft procurement from living, genetically related adult donors without injury to either donor or recipient, partial orthotopic liver transplantation (PLT) using a graft transected and warm perfused in situ was evaluated in beagles; the viability of the graft was assessed in terms of energy metabolism, including blood ketone body ratio (KBR), as well as of recipient survival. PLT was performed in two groups with venovenous bypass. The left half of the donor liver was transected in situ, flush perfused with 2 l lactated Ringer's solution (4 degrees C in group A, 20 degrees C in group B), and immediately implanted into the recipient, who was totally hepatectomized, care having been taken to leave the inferior vena cava intact. Four of seven dogs survived for 5 days or longer (longest, 8 days) in group A and six of eight dogs (longest, 20 days) in group B. Causes of death were gastrointestinal bleeding, intussusception, or infection but not graft dysfunction. In both groups the KBR decreased significantly during the anhepatic period, recovered rapidly to the pre-anhepatic level after revascularization, and was maintained within a normal range thereafter. No significant differences in the time course of changes in KBR were seen between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗