The use of the bio-pump with an interposed soft reservoir in replacement of descending thoracic aortic aneurysms

The centrifugal pump (bio-pump) as a temporary shunt during the operation of the descending thoracic aortic aneurysms was used as effective means of providing adequate circulation to the lower body. But in the acute excessive bleeding, estimates of the flow to the abdominal viscera as well as spinal cord are variable. We employed bio-pump with an interposed soft reservoir under low dose systemic heparinization in 2 cases of the descending thoracic aortic aneurysms. Both cases had been maintained adequate flow and perfusion pressure in the time of acute excessive hemorrhage, and there were no evidence of the organ failures due to microembolism. Furthermore, postoperative hemorrhage by using low dose heparin seemed to be unrisky. Compared with the previous method, bio-pump with an interposed soft reservoir provides adequate circulation to the lower body even if acute excessive bleeding occurred.     

Effect of induced hypotension on arterial blood ketone body ratio (AKBR)

Arterial blood ketone body ratio (AKBR; acetoacetate/beta-hydroxybutyrate) is known as a parameter to indicate the function of the liver cells. We evaluated the effects of induced hypotension with prostaglandin E1 (PGE1) or trimetaphan (TMP) on AKBR in patients without liver disease undergoing mastectomy. Almost no change was observed in AKBR before, during and after hypotension with PGE1, but slight diminution was observed during hypotension with TMP. No hepatic dysfunction, however, developed in these patients postoperatively. These findings suggest that usual hypotension with TMP may provoke no postoperative hepatic dysfunction in patients without liver disease. For the patient who required either hypotension of long duration or hypotension with other factors affecting function of liver (surgical procedures, drugs and others), we prefer PGE1 to TMP as a hypotensive drug. We should also adopt PGE1 when cardiovascular control with hypotensive drug is necessary in patients with liver disease.     

Research review: DNA polymerases as molecular markers of the regenerating capacity of hepatocytes

Hepatocyte regeneration has been widely investigated, with the mitotic index and the incorporation of [³H]thymidine being used as regeneration markers. We focused on the induction of DNA replication enzymes, particularly DNA polymerases (pol) α, δ, and ε. Using rat models, we have shown that the activity of pol α in crude liver extract well represents the regenerating capacity of hepatocytes. Using pol α as an indicator, we analyzed liver regeneration in rat models under various conditions: obstructive jaundice, external or internal biliary drainage, and the obstruction of portal vein branches. It has been revealed that the ligation of the common bile duct alone induces a certain amount of hepatocyte proliferation. It was striking that external biliary drainage suppressed regeneration capacity in cholestatic rat liver after partial hepatectomy. The strong regeneration in nonligated lobes induced by portal branch ligation was similar to the liver regeneration seen after partial hepatectomy with respect to the induction of DNA polymerases. Taken together, the aspects of DNA replication, particularly the induction of DNA polymerases, may contribute to shedding new light on the regeneration of human liver. This work was supported in part by a Grant-in-Aid for General Scientific Research and for Cancer Research from the Ministry of Education, Science and Culture, Japan, and by grants from the Uehara Memorial Foundation     

Modifications of temporal lobectomy according to the extent of epileptic foci and speech-related areas

The authors applied combined depth and subdural electrodes in patients with intractable complex partial seizures to detect the precise extent of epileptic foci and functionally map speech-related areas. The medial temporal structures were explored with depth electrodes and the lateral temporal cortex with subdural electrodes. On the speech-dominant side, electrical stimulation was given to demarcate the speech-related areas in the lateral temporal cortex. Based on these data, the extent of surgical resections was tailored to include as much of the epileptogenic areas as possible while preserving the functionally essential zones of the lateral cortex. According to the range of resection, three different approaches were employed for en bloc ablation of the lateral cortex and opening of the inferior ventricle. The results thus acquired have been satisfactory in terms of seizure control and the preservation of speech function.     

Possible mechanisms related to contraction of the bovine iris sphincter in the presence of acetylcholine and carbachol

Using tension-recording methods, we compared the effects of acetylcholine (Ach) and carbachol on the bovine iris sphincter. The isolated muscle strips were mounted in a 0.2 ml organ bath, through which Krebs solution at 36 °C flowed continuously. There was a tenthousandfold difference in potency between carbachol and Ach in this tissue. Neostigmine or eserine, acetylcholinesterase (AchE) inhibitors, produced a larger contraction of the muscle than did Ach. Ach-induced contractions were potentiated by low doses of anti-AchEs and were inhibited by atropine.This in vitro study suggests that Ach and/or endogenous chemical agents may be spontaneously released from tissues and that AchE activities in this tissue strongly inhibit or mask the Ach action, probably in order to protect the nerve terminals from released Ach.     

Involvement of enzymatic degradation in the inactivation of tachykinin neurotransmitters in neonatal rat spinal cord.

1. The possible involvement of enzymatic degradation in the inactivation of tachykinin neurotransmitters was examined in the spinal cord of the neonatal rat. 2. The magnitude of substance P (SP)- or neurokinin A (NKA)-evoked depolarization of a lumbar ventral root in the isolated spinal cord preparation was increased by a mixture of peptidase inhibitors, consisting of actinonin (6 microM), arphamenine B (6 microM), bestatin (10 microM), captopril (10 microM) and thiorphan (0.3 microM). The mixture augmented the response to NKA more markedly than that to SP. 3. In the isolated spinal cord-cutaneous nerve preparation, the saphenous nerve-evoked slow depolarization of the L3 ventral root was augmented by the mixture of peptidase inhibitors in the presence of naloxone (0.5 microM) but not in the presence of both naloxone and a tachykinin receptor antagonist, GR71251 (5 microM). 4. Application of capsaicin (0.5 microM) for 6 min to the spinal cord evoked an increase in the release of SP from the spinal cord. The amount of SP released was significantly augmented by the mixture of peptidase inhibitors. 5. Synaptic membrane fractions were prepared from neonatal rat spinal cords. These fractions showed degrading activities for SP and NKA and the activities were inhibited by the mixture of peptidase inhibitors. The degrading activity for NKA was higher than that for SP and the inhibitory effect of the mixture for NKA was more marked than that for SP. Although some other fractions obtained from homogenates of spinal cords showed higher degrading activities for SP, these activities were insensitive to the mixture of peptidase inhibitors.(ABSTRACT TRUNCATED AT 250 WORDS)