Yasuhiko Hashimoto

Inhalation anesthetics induce apoptosis in normal peripheral lymphocytes in vitro

Background The authors hypothesized that perioperative lymphocytopenia is partially caused by apoptosis of lymphocytes induced by inhalation anesthetics. Therefore, they evaluated whether sevoflurane and isoflurane induce apoptosis of normal peripheral lymphocytes. Methods Normal peripheral blood mononuclear cells were exposed to sevoflurane and isoflurane, and the percentages of apoptotic lymphocytes was measured by Annexin V-fluorescein isothiocyanate–7-amino actinomycin D flow cytometry after 24 h of exposure (0.5, 1.0, and 1.5 mm) and after 6, 12, and 24 h of exposure (1.5 mm). The percentages of lymphocytes with caspase 3–like activity were also measured after 24 h of exposure (1.5 mm). Results The percentages of apoptotic lymhocytes were increased in a dose-dependent manner (controls: 5.1 ± 1.4%; sevo-flurane: 7.3 ± 1.3% [0.5 mm], 9.1 ± 1.5% [1.0 mm], 12.6 ± 2.1% [1.5 mm]; isoflurane: 7.5 ± 1.6% [0.5 mm], 10.5 ± 1.5% [1.0 mm], 16.3 ± 2.7% [1.5 mm]) after 24 h of exposure and in a time-dependent manner (controls: 1.2 ± 0.4% [6 h], 3.4 ± 0.7% [12 h], 5.6 ± 1.2% [24 h]; sevoflurane: 1.8 ± 0.4% [6 h], 6.4 ± 1.2% [12 h], 11.3 ± 2.2% [24 h]; isoflurane: 2.6 ± 0.5% [6 h], 8.8 ± 1.5% [12 h],16.0 ± 1.9% [24 h]) at the concentration of 1.5 mm. The percentages of lymphocytes with caspase 3–like activity were increased (controls: 10.0 ± 1.1%; sevoflurane: 13.8 ± 1.2%; isoflurane: 17.0 ± 1.3%). Conclusions Both sevoflurane and isoflurane induced apoptosis in peripheral lymphocytes in dose-dependent and time-dependent manners in vitro.

Role of histamine H1 receptor in pain perception: a study of the receptor gene knockout mice

To study the participation of histamine H(1) receptors in pain perception, histamine H(1) receptor knockout mice were examined for pain threshold by means of three different kinds of nociceptive tasks. These included assays for thermal nociception (hot-plate, tail-flick, paw-withdrawal), mechanical nociception (tail-pressure), and chemical nociception (abdominal constriction, formalin test, capsaicin test) which evoked pain by the activation in nociceptive Adelta and C fibers. The mutant mice lacking histamine H(1) receptors showed significantly fewer nociceptive responses to the hot-plate, tail-flick, tail-pressure, paw-withdrawal, formalin, capsaicin, and abdominal constriction tests. Sensitivity to noxious stimuli in histamine H(1) receptor knockout mice significantly decreased when compared to wild-type mice. This data indicates that histamine plays an important role in both somatic and visceral pain perceptions through histamine H(1) receptors. The difference in the effect of histamine H(1) receptors antagonist, the active (D-) and inactive (L-) isomers of chlorpheniramine on ICR mice further substantiates the evidence of the role of histamine H(1) receptors on pain threshold.

Elevated plasma levels of interleukin-6, interleukin-8, and granulocyte colony-stimulating factor during and after major abdominal surgery

STUDY OBJECTIVE To evaluate the influence of major abdominal surgery on the plasma levels of inflammatory cytokines interleukin-6 (IL-6), interleukin-8 (IL-8) and granulocyte colony-stimulating factor (G-CSF). DESIGN Prospective study. SETTING University hospital. PATIENTS 10 ASA physical status I and II patients undergoing upper abdominal surgery. INTERVENTIONS All patients received combined general-epidural anesthesia with isoflurane and nitrous oxide, after insertion of an epidural catheter at T7-T9 dosed with 1.5% lidocaine. MEASUREMENTS AND MAIN RESULTS Plasma cytokine (IL-6, IL-8, G-CSF) levels were determined with an enzyme-linked immunosorbent assay (ELISA) at pre-anesthesia, 0, 2, and 4 hours during surgery, and at the end of surgery, followed by sampling on the morning of postoperative days 1 (POD1) and 3 (POD3). Plasma cortisol levels were also determined. The plasma levels of IL-6 increased gradually after skin incision and reached the maximal value at the end of surgery (p < 0.001). IL-8 levels also increased from the baseline value to their maximum at the end of surgery (p < 0.05). G-CSF levels were elevated from the pre-anesthesia value to their maximum by the end of operation (p < 0.005). Plasma cortisol levels were increased after skin incision (p < 0.001). Postoperative cytokine levels correlated significantly with each other (r = 0.68, p < 0.05 for IL-6 vs. IL-8; r = 0.81, p < 0.005 for IL-6 vs. G-CSF; and r = 0.84, p < 0.005 for IL-8 vs. G-CSF). Postoperative IL-6 levels and intraoperative blood loss correlated significantly (r = 0.64, p < 0.05). CONCLUSIONS These results suggest that major upper abdominal surgery stimulates the release of inflammatory cytokines presumably from the operation site. Further study is warranted to evaluate the modulation of inflammatory responses in the perioperative period.

Interleukin-10 Production During and After Upper Abdominal Surgery

STUDY OBJECTIVE To evaluate the influence of major abdominal surgery on the plasma levels of interleukin-10 (IL-10). DESIGN Prospective study. SETTING University hospital. PATIENTS 10 ASA physical status I and II patients undergoing upper abdominal surgery. INTERVENTIONS All patients received combined general-epidural anesthesia with isoflurane and nitrous oxide, after insertion of an epidural catheter at T8-T9 dosed with 1.5% lidocaine. MEASUREMENTS AND MAIN RESULTS Plasma interleukin-6 (IL-6), interleukin-8 (IL-8), and IL-10 levels were determined with an enzyme-linked immunosorbent assay at preanesthesia, 0, 2, and 4 hours during surgery, and at the end of surgery, followed by sampling on the morning of postoperative days 1 (POD1) and 3 (POD3). Before anesthesia and at 0 hours of surgery, IL-10 was not detected. In all ten patients, the plasma levels of IL-10 showed significant elevations and achieved their maximal value 4 hours after the skin incision (p < 0.05 vs. baseline). The plasma IL-10 levels returned to preanesthesia levels on POD3. The plasma levels of IL-6 and IL-8 also increased in the perioperative period. The peak cytokine levels correlated (r = 0. 915, p = 0.0001 for IL-6 vs. IL-8; r = 0.82, p = 0.025 for IL-6 vs. IL-10; and r = 0.641, p = 0.06 for IL-8 vs. IL-10). The peak plasma IL-10 levels significantly correlated with the amount of intraoperative blood loss (r = 0.69, p < 0.05). CONCLUSIONS In patients undergoing major abdominal surgery, plasma IL-10 levels were elevated during and after operation. IL-10 may modulate the inflammatory responses in the perioperative period.

Histamine H1 receptor-mediated inhibition of potassium-evoked release of 5-hydroxytryptamine from mouse forebrains

The release of endogenous serotonin and dopamine from slices of mouse forebrains induced by high extracellular K(+) was examined in histamine H1 receptor knockout mice. The release of 5-hydroxytryptamine (5-HT) evoked by 30 mM K(+) significantly decreased in the presence of 10-50 microM histamine in wild-type mice, but was not inhibited in the mutant mice. Histamine H1 receptor-mediated inhibition of serotonin release in wild-type mice was also observed in the presence of thioperamide, an H3 antagonist. From these data, we postulate that endogenous histamine indirectly inhibits the release of 5-HT through H1 receptors in addition to H3 receptors. The treatment of 2 microM tetrodotoxin could partly abolish the effects of histamine on K(+)-evoked 5-HT release. Bicuculline, a GABA(A) antagonist, could reverse the histamine-induced inhibition of 5-HT release in wild-type mice, suggesting that H1 receptors facilitate the release of GABA, which in turn inhibits 5-HT release through GABA(A) receptors. The difference in the effects of d- and l-chlorpheniramine on K(+)-evoked 5-HT release in wild-type mice further supports the evidence of the function of H1 receptor modulating 5-HT release.

Comparison between in vivo and in vitro pharmacokinetics of succinylcholine in humans.

AbstractPurpose. To compare the in vivo and in vitro pharma-cokinetics of succinylcholine (SCh) in humans. Methods. A bolus of SCh 1 mg·kg−1 (n = 7) or 2 mg·kg−1 (n = 11) was given to 18 patients anesthetized with thiopental. Arterial blood samples for determination of in vivo SCh concentrations were collected every 30 s for 5 min. Another 20-ml blood sample was obtained before induction of anes-thesia for determination of in vitro SCh. Concentrations of SCh were measured by high-performance liquid chromato-graphy. In vivo and in vitro concentrations of SCh vs time data were analyzed by the one-compartment model. Results. The respective in vivo and in vitro pharmacokinetic parameters (SCh 1 mg·kg−1vs SCh 2 mg·kg−1) were as follows: Plasma clearance was 4.17 ± 2.37 and 1.85 ± 0.28 l·min−1, P < 0.05, vs 2.91 ± 2.01 and 1.27 ± 0.43 l·min−1, P < 0.05. Elimination half-life was 25.4 ± 10.6 and 47.4 ± 5.4 s, P < 0.002 vs 26.3 ± 10.0 and 75.2 ± 21.8 s, P < 0.00005. Conclusion. These results suggest that the rapid disap-pearance of SCh from the circulation is due to diffusion out of the blood vessels rather than to enzymatic hydrolysis.

Effects of unilateral vagotomy on nitric oxide synthase and histamine H3 receptors in the rat dorsal vagal complex

Nitric oxide synthase (NOS) and histamine H3 receptors are both markedly increased by neuronal injuries. To examine whether peripheral axotomy produced differential changes in NOS and H3 receptors, both NOS and H3 receptors were measured in the dorsal vagal complex after unilateral vagotomy. The presence of NOS-positive neurons was examined using both NADPH-diaphorase histochemistry and neuronal NOS-immunohistochemistry in rats vagotomized at the mid-cervical level. NADPH-diaphorase activity and NOS-immunoreactivity were markedly enhanced on the dorsal motor nucleus of the vagus (DMX) and in the ambiguous nucleus at the denervated side. Intraperitoneal injection of NOS inhibitors, N omega-nitro-L-arginine (10 mg/kg) or dexamethasone (0.5 mg/kg) attenuated the increase in NADPH-diaphorase activity. Glial fibrillary acidic protein (GFAP) was similarly induced 2 weeks after vagotomy in the vagal complex and surrounding area. Histamine H3 receptors in the vagal complex were visualized with [3H]N alpha-methylhistamine. The ligand-labeled H3 receptors were mainly located at the nucleus of the solitary tract (NST). The densities of H3 receptors did not change in the NST after unilateral vagotomy. These results suggest that peripheral axotomy such as mid-cervical vagotomy preferentially induces NOS in damaged neurons without affecting the level of H3 receptors.

Effect of surfactant on respiratory failure associated with thoracic aneurysm surgery.

OBJECTIVE To study the effects of surfactant administration on the left lung after surgical repair of descending aortic aneurysms on postoperative respiratory failure. DESIGN Randomized, prospective, controlled study. SETTING Clinical investigation. PATIENTS Eleven patients with respiratory failure associated with thoracic aneurysm surgery. INTERVENTION Eleven adult patients with acute respiratory failure (PaO2/FIO2 <300 torr [<40 kPa]) after surgical repair of descending aortic aneurysms. The artificial surfactant (30 mg/kg) was given to the operated side of the lung by intrabronchial instillation in six patients (surfactant group), whereas nothing was instilled in the other five patients (control group). MEASUREMENTS AND MAIN RESULTS Hemodynamic parameters, blood gas, and peak inspiratory pressure were measured at the end of surgery, before surfactant instillation, and at 2, 6, 12, 24, and 48 hrs after surfactant instillation. At the end of surgery, the mean +/- SEM values of the PaO2/FIO2 ratio were 204 +/- 25 torr (27.2 +/- 3.3 kPa) in the surfactant group and 240 +/- 26 torr (32.0 +/- 3.5 kPa) in the control group. After 2, 6, 12, and 48 hrs, improvements in the PaO2/FIO2 ratios were observed in the surfactant group, whereas the control group showed no improvement. Two hours after surfactant instillation, the mean value in the PaO2/FIO2 ratio was significantly higher in the surfactant group (318 +/- 24 torr [42.4 +/- 3.2 kPa]) (p < .05) compared with the control group values (240 +/- 34 torr [32 +/- 4.5 kPa]). CONCLUSION Surfactant administration immediately after surgery restored gas exchange in postoperative respiratory failure associated with thoracic aneurysm surgery.

Effects of isoflurane on oxygenation during one‐lung ventilation in pulmonary emphysema patients

Background: Hypoxic pulmonary vasoconstriction has an important role in human one‐lung ventilation (OLV) in the lateral decubitus position under general anesthesia. During OLV, inhalational anesthesia may inhibit hypoxic pulmonary vasoconstriction and the decrease in arterial oxygenation. We studied the effect of isoflurane administration on arterial oxygen tension in chronic obstructive pulmonary disease patients.

Inotropic Effects of Non-depolarizing Muscle Relaxants in Isolated Canine Heart Muscle

The inotropic effects of five non-depolarizing muscle relaxants were examined using an isolated canine heart muscle preparation. Except for fazadinium, all drugs were studied in their commercially available forms. d-Tubocurarine chloride (dTc) and metocurine iodide (MTC) produced dose-dependent decreases in isometric force (F) and the maximum velocity of force development (dF/dt) at concentrations greater than 22.5 × 10−3 g/L for dTc and greater than 15.0 × 10−3 g/L for MTC, concentrations which are 3 and 6 times higher than estimated clinical serum concentrations, respectively. Myocardial depression was about 3 times less with MTC than with dTc at equipotent concentrations. The degree of depression in F and dF/dt produced by MTC was almost identical with that produced by phenol, a preservative of MTC, indicating that MTC-induced myocardial depression may be due to the effect of the preservative. Pancuronium bromide (PC) produced a dose-dependent increase in F and dF/dt and decrease in the time to peak force. PC-induced changes in F, dF/dt, and time to peak force were inhibited by administration of propranolol 10−6 M. The results indicate that PC possesses a positive inotropic effect mediated by beta-adrenergic stimulation. Alcuronium chloride did not change F or dF/dt at concentrations from 5.0 × 10−3 to 60.0 × 10−3 g/L. Fazadinium bromide increased F and dF/dt slightly at a low concentration (1.875 × 10−2 g/L), but further increases in its concentration returned the values of F and dF/dt to control levels. F and dF/dt were not altered in vitro by concentrations of relaxants that would be anticipated in plasma in vivo in patients given clinically effective doses of 0.3 mg/kg of dTc, 0.1 mg/kg of MTC or PC, 0.2 mg/kg of alcuronium chloride, or 0.75 mg/kg of fazadinium bromide.