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Biomedical subjects

Y Kamiyama

Publications and source records attributed to Y Kamiyama.

At least 199 records · Page 11Linked to original sources
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

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↗
PubMed1984

Caudal anaesthesia for upper abdominal surgery in infants and children: a simple calculation of the volume of local anaesthetic.

Where the use of non-depolarizing muscle relaxants and antagonists is undesirable in infants and children undergoing abdominal surgery, caudal anaesthesia is frequently adopted, combined with light general anaesthesia. A simple calculation has been derived to determine the volume of local anaesthetic needed to obtain a higher effective anaesthetic level (up to T4-5) for upper abdominal operations using caudal anaesthesia. Clinically, a linear correlation was found between an empirically injected volume of local anaesthetic and the distance from C7 to the sacral hiatus in 21 infants and children. A similar relationship was also demonstrated radiographically in 16 cadavers by studying the spread of radio-opaque solution in the epidural space introduced by the caudal technique. From both statistical studies, a simple formula to determine the required volume of local anaesthetic for upper abdominal surgery was derived: V = D-13, where V is the volume of local anaesthetic in ml and D is the distance from C7 to the sacral hiatus in cm.

Abdomen↗
PubMed1983

Metabolic abnormalities associated with postoperative organ failure. A redox theory.

We studied metabolic abnormalities of postoperative organ failure in 55 patients and classified them into four groups according to the postoperative changes in the arterial blood-ketone body ratio (acetoacetic acid-beta-hydroxybutyric acid) reflecting hepatic mitochondrial redox potential: patients in group A had no decrease below 0.7, patients in group B had a transient decrease to 0.4, patients in group C had a progressive decrease to below 0.4, and patients in group D (terminal stage) had a decrease to below 0.25. All group A and B patients tolerated their operations well; the group C and D patients had multiple organ failure. In groups B, C, and D, plasma concentrations of alanine, proline, phenylalanine, and tyrosine were negatively correlated with the blood--ketone body ratio and the molar ratios between the plasma concentrations of branched-chain amino acids and aromatic amino acids were positively correlated with the blood--ketone body ratio. Hepatic energy deficit associated with decreasing blood-ketone body ratio may be the metabolic basis of postoperative organ failure.

3-Hydroxybutyric Acid↗
PubMed1983

Relationship between initial hepatic uptake of indocyanine green and hepatic energy status in hepatectomized rabbits.

The relationship between initial hepatic uptake of indocyanine green (ICG) and hepatic energy status was studied in about 70% hepatectomized rabbits. At 24 h after hepatectomy, the initial plasma disappearance rate (K) and the maximal removal rate (Rmax) of ICG fell to 27 and 26%, respectively, and the mitochondrial phosphorylative activity was enhanced maximally with a concomitant decrease in the energy charge ( (ATP+1/2ADP)/(ATP+ADP+AMP) ) level. Afterward, the initial reduction of ICG removal rate was followed by a rapid increase in week 1 and more gradual return to preoperative values by week 6 after hepatectomy. In the early period after hepatectomy (1-7 days), the mitochondrial phosphorylative activity was the higher the smaller the %K value was, while in the late period after hepatectomy (1-6 weeks), the mitochondrial phosphorylative activity remained unchanged irrespective of increasing %K. It is suggested that the mitochondrial phosphorylative activity may be a better guide to evaluate the functional status of the remnant liver than the initial hepatic uptake of ICG, especially in the early period after hepatoctomy.

Adenosine Triphosphate↗
PubMed1983

Contribution of the arterial blood ketone body ratio to elevate plasma amino acids in hepatic encephalopathy of surgical patients.

To clarify the role of hepatic metabolic derangements in elevated plasma amino acid levels, the patterns of plasma amino acids in 17 surgical patients with hepatic failure were analyzed in relation to the blood ketone body ratio (acetoacetate to beta-hydroxybutyrate), which reflects the mitochondrial redox potential. The blood ketone body ratios were 0.49 in eight alert patients with hepatic failure and 0.28 in nine patients with grade IV hepatic coma, compared with values of 0.79 to 6.42 in patients with healthy livers. The plasma concentrations of alanine, proline, phenylalanine, and tyrosine were negatively correlated with the blood ketone body ratio. Elevations of alanine, phenylalanine, tyrosine, and glutamate were greater in comatose patients than in alert patients. Also, the molar ratios between the plasma concentrations of the branched-chain amino acid and the aromatic amino acids were positively correlated with the blood ketone body ratio (r = 0.78, p less than 0.0001). We suggest that a reduced mitochondrial redox potential, coupled with enhanced muscle breakdown, results in inhibition in the entrance of the amino acids into the Krebs' cycle and then the characteristic changes in the free amino acid patterns which result in hepatic coma.

Adult↗
PubMed1983

Mechanism of suppressed renin-angiotensin system in spontaneously hypertensive rat (SHR).

Plasma renin concentration (PRC) of SHR decreased with the elevation of blood pressure. In addition in vitro study of basal renin release from kidney slices obtained from SHR produced similar results. However kidney renin activity and total renin content in kidney of SHR were not less than those of Wistar rats. These results indicate that the decreased renin release from kidney might be responsible for the suppression of renin-angiotensin system of SHR after the development of hypertension. Administration of fusaric acid, a dopamine-beta-hydroxylase inhibitor markedly decreased urinary excretion of catecholamine and prostaglandin E in both SHR and Wistar rat and abolished the development of hypertension in SHR. PRC of SHR which became normotensive by fusaric acid administration (normotensive SHR), increased up to the level of control Wistar rats. Therefore suppressed renin-angiotensin system was not observed in normotensive SHR. Nevertheless basal renin release from kidney slices obtained from normotensive SHR was still less than that from control Wistar rats. As urinary catecholamine and prostaglandin E excretion were decreased by fusaric acid administration, these well-known renin stimulators could not be responsible for the reversal of suppressed renin-angiotensin system in normotensive SHR. Rather decreased arterial blood pressure in normotensive SHR lowered renal perfusion pressure, and led to the stimulation of renin release up to the levels of control Wistar rats by the activation of renal arteriolar baroreceptors.

Angiotensin II↗
PubMed1982

Clinical experience of postoperative hepatic failure treatment with pig or baboon liver cross-hemodialysis with an interposed membrane.

The present study emphasizes the principle of using liver support to restore the blood ketone body ratio (acetoacetate/beta-hydroxybutyrate), which reflects the redox potential of liver mitochondria and correlates with hepatic energy charge (ATP + 0.5ADP/ATP + ADP + AMP). Eleven surgical patients with grade IV hepatic coma were treated by an ex vivo pig or baboon liver cross-hemodialysis with an interposed Cuprophan membrane when their blood ketone body ratios had decreased to below 0.4 compared with the normal of above 0.7. Three patients were treated by cross-hemodialysis using a standard Cuprophan membrane dialyzer without increase of blood ketone body ratio and without marked beneficial effect. However, five of eight patients who had blood ketone body ratios of above 0.25 became fully alert after treatment by cross-hemodialysis using the larger pore size and greater surface area Cuprophan membrane, concurrent with a rise in the decreased blood ketone body ratio, and three of them were later discharged. By contrast, in the three patients with blood ketone body ratios below 0.25, there was no restoration of consciousness and no improvement in their blood ketone body ratios by this liver support. It is suggested that, as long as the blood ketone body ratio remained over 0.25, this metabolic liver support is effective in restoring grade IV hepatic coma.

Aged↗
PubMed1982

The effects of heterologous liver cross-hemodialysis on adenylate energy charge of the remnant liver after major hepatic resection.

The effect of liver support on the adenylate energy charge (ATP + 0.5ADP)/(ATP + ADP + AMP) of the remnant liver after major hepatic resection was studied in rabbits. The present study emphasized the principle of restoring the decreased energy charge level of the remnant liver after major hepatic resection by use of an ex vivo heterologous liver cross-hemodialysis with an interposed Cuprophan membrane. The energy charge level provides the cell with a very sensitive intracellular control mechanism. Regulatory enzymes from biosynthetic sequences exhibit very little activity at low levels of energy charge, and their activities increase sharply at high-energy charge levels. The energy charge level of the remnant liver maximally decreased from the control level of 0.860 to 0.767 at 24 hours after 70% hepatectomy. The energy charge level increased from 0.767 to 0.857 after two hours of cross-hemodialysis with an interposed Cuprophan membrane between the 24-hour, 70% hepatectomized rabbit and an ex vivo pig liver with high energy charge. The above results suggest that this ex vivo pig cross-hemodialysis may be effective for biosynthesis in the regenerative processes of the remnant liver.

Adenosine Monophosphate↗
PubMed1981

Effects of hypothermia on energy metabolism of metabolically loaded liver.

The effects of hypothermia on adenine nucleotide level, mitochondrial metabolism and redox state of the remnant liver were studied in 25, 50, 70 and 93% hepatectomized rabbits. In 25% of the hepatectomized rabbits, energy charge levels and mitochondrial phosphorylative activities remained unchanged, while in 50 and 70% hepatectomized rabbits, the energy charge levels decreased maximally at 24 hours after hepatectomy with a concomitant rise of mitochondrial phosphorylative activity. In 93% hepatectomized rabbits, the energy charge levels decreased rapidly without enhancement in mitochondrial phosphorylative activity and these rabbits died within 12 hours after hepatectomy. Body cooling significantly increased the energy charge of the remnant liver with further enhancement in mitochondrial phosphorylative activity in 25, 50 and 70% hepatectomized rabbits, but did not increase the energy charge in 93% hepatectomized rabbits. On the other hand, during body rewarming, the energy charge levels of the remnant liver decreased. More than 60% of 70% hepatectomized rabbits died during body rewarming, while all of 50% or less hepatectomized rabbits remained alive. Thus, body cooling may provide remarkable protection for the remnant liver from an energy crisis under the condition that compensatory mitochondrial enhancements are present.

Adenine Nucleotides↗
PubMed1981

Circulating hepatodepressant factors decreasing the energy charge levels of the remnant liver after hepatectomy.

In 25% hepatectomized rabbits, the mitochondrial phosphorylative activity and the energy charge [(ATP + 1/2 ADP)/(ATP + ADP + AMP)] levels of the remnant liver remained unchanged after hepatectomy. In 70% hepatectomized rabbits, the energy charge levels of the remnant liver decreased maximally 24 h after hepatectomy (p less than 0.001), simultaneously with a marked enhancement of mitochondrial phosphorylative activity (P less than 0.001). Afterward, both returned to normal levels within 4 days. In 93% hepatectomized rabbits, the energy charge levels fell rapidly, with an inhibition of mitochondrial phosphorylative activity, within 6 h after hepatectomy. When a 24-hour 70% hepatectomized rabbit was cross-circulated with a normal rabbit, the energy charge in the liver of the normal partner decreased to 0.732 at 30 min after the blood exchange and then returned to 0.855 while that in the remnant liver of the hepatectomized partner increased from 0.767 to 0.820 (p less than 0.001). Also, the energy charge values of a 24-hour 70% hepatectomized rabbit were increased by the extracorporeal normal liver perfusion. It is suggested that a decrease in the energy charge of the remnant liver is due, at least partly, to the accumulation of the substances consuming hepatic energy (hepatodepressant factors) in the systemic blood of hepatectomized rabbits.

Adenine Nucleotides↗