Yoichi Shirakawa

Memory Facilitation by Posttraining Exposure to Halothane, Enflurane, and Isoflurane in ddN Mice

The effect of low and high concentrations of halothane, enflurane, and isoflurane on posttraining memory function was studied in male ddN mice. Mice were trained to escape an aversive electric foot shock as an unconditioned stimulus within 3 s after being exposed to light and a buzzer as a conditioned stimulus. Immediately after training (first session: 30 trials), the animals were exposed to halothane, enflurane, or isoflurane avoidance task (second session: 30 trials) 22 h after cessation of exposure. The performance ratios, [B/A] (i.e., A is the score in the first session, and the score in the second) were compared between the anesthetized and for min and then were tested again On the groups and their respective control (nonanesthetized) groups. Mean performance ratios in the control groups ([B/A]c) ranged from 136.8% to 163.9% and those in the aesthetized groups ([B/A]a) ranged from 151.4% to 174.7%. [B/A] in each anesthetized group exceeded [B/A] in its corresponding control group. [B/A]a significantly exceeded [B/A]c by 13.1% in the 1.23 minimum alveolar concentration (MAC) enflurane group (P < 0.05). These results suggest that posttraining exposure to volatile anesthetics facilitates memory.

Differences in antithrombin III activities by administration method in critical patients with disseminated intravascular coagulation: a pharmacokinetic study.

Pharmacokinetic (PK) data for antithrombin III (AT) are limited in the critical patients. We therefore performed PK analysis using a two-compartment model and also examined whether plasma AT activity would change depending on two administration methods, AT agent at 500 U/8 h (divided group) or 1,500 U/24 h (combined group) for 3 days, a regulated dosage for disseminated intravascular coagulation (DIC) treatment in Japan, in critical patients with DIC. Clinical prospective randomized study. A high care unit in a university hospital. Twenty-four consecutive critical patients with DIC. Ages ranged from 34 to 91 years. Acute physiology age and chronic health evaluation II scores were 25 to 35. Antithrombin III activities in the combined group caused remarkable transient increases but returned to near the preadministration level 24 h after the infusion. Antithrombin III level in the divided group showed small elevations on each session; therefore, steady increases were found after serial administrations of the agent. On the third day, AT trough activities in the divided group were significantly higher than those in the combined group (P = 0.005). However, peak AT activities in the combined group after AT administration were higher than those in the divided group throughout the study (P = 0.024). Aggravation of bleeding tendency occurred more frequently in the combined group (P = 0.03). Half-life times on the distribution phase in both groups were remarkably shorter than those of previously reported control in congenital AT deficiency. This suggests an increased vascular permeability in the critical patients in this study. Distribution volume in the patients here increased significantly as compared with the previous controls. This is the first PK report using a two-compartment model to demonstrate that remarkable increases in vascular permeability and distribution volume occur in critical patients with DIC, and if the same dose is administered intermittently in such PK situation, AT administration in divided manner can maintain plasma AT trough activity higher than that in the combined method.

Interactions between volatile anesthetics and dipalmitoyl phosphatidylcholine liposomes as studied by fluorometry with a thiacarbocyanine dye

The effects of volatile anesthetics on the properties of dipalmitoyl phosphatidylcholine liposome were investigated by fluorescence spectroscopy with a thiacarbocyanine dye (3,3′-dioctadecyl-2,2′-thiacarbocyanine) which is sensitive to the viscosity and the dielectric constant of the environment. Seven volatile anesthetics, halothane, enflurane, isoflurane, methoxyflurane, sevoflurane, diethylether and chloroform were used. All anesthetics decreased the phase transition temperature of the liposome and increased the effective dielectric constant of the water-liposome interface. The increase of the effective dielectric constant was attributed to the release of the hydrated water molecules from the membrane surface. The increment of the effective dielectric constant depended on the thermodynamic activity of anesthetics in the solution, and was not affected seriously by the kind of anesthetics. On the other hand, the degree of the depression of the phase transition temperature depended on the molar concentrations of anesthetics. Considering from the Ferguson’s report, which is dealt with the relationship between the physiological effect and the thermodynamic activity, the effect of anesthetics on the effective dielectric constant of the membrane surface is more correlated to the anesthetic action than the effect on the phase transition temperature.

Fourier Transform Infrared (FTIR) Analysis of Volatile Compounds in Expired Gas for the Monitoring of Poisonings 1.Ethanol

Many chemical compounds in the environment can cause poisonings. To determine and evaluate medical treatments, and to prevent poisonings, qualitative and quantitative analyses of chemical compounds are necessary. In practical poisoning cases, analyses are usually performed using urine and/or blood of patients. GC and HPLC are the most popular methods for this purpose. In patients poisoned with volatile compounds, some of the compounds are usually eliminated in the expired gas. Therefore, expired gas can be a useful sample, but is rarely used clinically. As the method of obtaining expired gas is the least invasive, it could be the most practical material in such cases if an appropriate analysis technique is developed. Infrared (IR) spectroscopy is a useful instrument for the qualitative and quantitative analysis of gases, liquids and solid samples. However, it was previously very difficult to apply this method to biological samples due to interference by the strong absorption of water. Recently, the introduction of the Fourier transform infrared system (FTIR) overcame this problem, and now FTIR is applicable to biological samples. However, clinical use of FTIR is rare. Setiawan et al. (1) measured the concentration of boron compounds in human blood using FTIR. The practical application of FTIR to monitor inhalational compounds is mainly limited to industrial hygienic approaches. Some studies (2–5) dealt with the application of FTIR for monitoring volatile organic compounds in the workspace. Among them, Franzblau et al. (2) examined human exposures to methanol vapor using a 47 m stainless steel chamber. They measured the concentrations of methanol in the chamber, expired gas and blood using transportable FTIR and HS-GC. We examined the availability of FTIR to the clinical analysis of expired gas for monitoring volatile compounds poisonings. In the present study, we used ethanol as a volatile compound. For the human study using volunteers, ethanol is the most suitable volatile compound. With respect to other organic compounds, many ethical problems would occur to administer. For ethanol, many sensitive alcohol checkers are working worldwide (6,7), because it is the most common organic compound and its poisoning is sometimes a serious problem. We did not use alcohol checkers but used a common FTIR spectrometer. This instrument was laboratory based, not so expensive, and can detect most organic compounds while alcohol checkers can detect only ethanol. The method described here with ethanol could be easily applied to other organic compounds. Using human volunteers and rabbits, ethanol concentrations in expired gas after oral administration were measured by FTIR. The obtained data were compared with the reported values, and the applicability of this method was discussed. To evaluate the correlation between concentrations in expired gas and blood, the concentration in blood was also measured with GC.

Non-specific hyperamylasemia in shosin beri-beri

Several reports demonstrate non-specific hyperamylasemia in cardiac surgery or diabetic ketoacidosis. We report here for the first time non-specific hyperamylasemia in a cardiovascular beri-beri case who showed shock with severe metabolic acidosis. Her echocardiography revealed hyperkinetic wall motion of the small left ventricle. Despite intravascular volume expansion in parallel with dopamine administration, her blood pressure did not recover. Abdominal computed tomography (CT) did not reveal pancreatic swelling or any other signs of acute pancreatitis. Her history suggested a possibility of cardiovascular beri-beri due to chronic alcoholism. Thiamine administration dramatically reversed her haemodynamic derangements, metabolic acidosis and even relieved her abdominal pain. Isozyme examinations for hyperamylasemia showed that most of the serum amylase consisted of salivary type. This case report expands our information on non-specific hyperamylasemia encountered in the emergency setting.