Effects of intravenously administered lidocaine on pulmonary vagal afferents and phrenic nerve activity in cats

The ability of lidocaine to suppress activity of single vagal afferent fiber and that of phrenic nerve was studied in 20 cats anesthetized with pentobarbital. Slowly adapting stretch receptors (SAR, n = 16) and rapidly adapting stretch receptors (RAR, n = 7) were identified by their discharge pattern to pulmonary inflation. Intravenous lidocaine (1mg·kg^–1 or 2mg·kg^–1) produced a suppression of SAR activity but not of RAR activity. Suppression of phrenic nerve activity lasted much longer than that of SAR. These findings indicate that iv lidocaine acts more dominantly on CNS than on peripherals. We conclude that iv lidocaine prevents cough and hemodynamic changes caused by airway manipulation mainly through its action on CNS and not on peripherals (peripheral nerves or their receptor).(Aoki M, Harada Y, Namiki A, et al.: Effects of intravenously administered lidocaine of pulmonary vagal afferents and phrenic nerve activity in cats. J Anesth 6: 395–400, 1992)     

Epidural administration and analgesic spread: Comparison of injection with catheters and needles

This study was designed to investigate differences in epidural analgesic spread between catheter and needle injections in 48 patients with comparable physical characteristics. The spread of analgesia in the catheter injection group with a 0.24ml·sec^–1 injection rate (n = 16) was 16.8 ± 1.5 spinal segments and that in the needle injection group at the same injection rate (n = 16) was 12.5 ± 1.8 spinal segments (P 0.01). Needle injection at the faster rate of 1.2ml*237sec^–1 (n = 16) produced a significantly greater spread of analgesia than with the 0.24ml·sec^–1 rate through the needle (16.2 ± 1.6 vs 12.5 ± 1.8 spinal segments, P 0.01). Thirteen of 16 patients receiving the fast needle injection complained of back compression or discomfort during the injection.The injection through an epidural catheter and the fast (1.2ml·sec^–1) injection through a needle produced extensive and equivalent epidural analgesic spread. However, because of patients discomfort with fast injection through the needle, the authors conclude that when using continuous epidural anesthesia, the initial injection of local anesthetic should be administered through the epidural catheter not the needle.(Omote K, Namiki A, Iwasaki H: Epidural administration and analgesic spread: comparison of injection with catheters and needles. J Anesth 6: 289–293, 1992)     

Technical aspects of hepatic portal dissection in biliary atresia.

During the past 8 yr, 37 patients with a noncorrectable type of biliary atresia have undergone hepatic portoenterostomy or portocholecystostomy at the Kobe Children's Hospital. The hepatic portal dissections employed in this series were classified as "supraportal" (9 procedures), "portal" (25 procedures), and "infra-portal" (3 procedures) based on the level at which the fibrous mass at the porta hepatis was transsected as determined by the operative record and the pathologic findings. Successful biliary drainage was achieved in 19 out of 25 patients (76%) with a "portal" type of dissection, while 1 out of 9 with "supra-portal" and none out of 3 with "infra-portal" type dissections were successful in this respect. Of the 19 patients who achieved significant biliary flow, 8 have lived for 2--7 yr without jaundice and 3 others are jaundice-free for shorter intervals.     

Dynorphins directly inhibit neuronal nicotinic acetylcholine receptors in PC12 cells

The authors have previously reported that dynorphin A (1-17), an endogenous kappa opioid agonist, inhibits the current mediated through neuronal nicotinic acetylcholine receptors (nAChRs) without the involvement of opioid receptors or G-proteins. We have further characterized this action to elucidate the mechanisms. The nicotine-induced current was studied in PC12 cells using patch-clamp techniques. In the whole-cell configuration, four kinds of dynorphins with different lengths, dynorphin A (1-17) (1-13) (2-13) and (1-8), similarly inhibited the nicotine-induced inward current at 1 microM and accelerated the current decay. The inhibition by dynorphin A (1-17) was not antagonized by the increasing concentrations of nicotine. The current-voltage relationship revealed that dynorphin's inhibition was voltage independent at the membrane potentials from -30 to -70 mV. The inhibition was not affected by pretreatment with pertussis toxin (PTX) or inclusion of staurosporine into the pipette solution. The inhibitory effect of dynorphin A (1-17) was well preserved in the outside-out patch configuration. Analysis of the nicotine-induced noise and single-channel kinetics revealed that dynorphin A(1-17) reduced open time without changing the amplitude of the unitary current. We found that the inhibitory effect on neuronal nAChRs is shared by all four dynorphins studied. The inhibition appears to be non-competitive and voltage independent. The outside-out recording together with other experiments indicated that a major part of this inhibition is not mediated through cytoplasmic messengers, but based on the direct action of dynorphins on neuronal nAChRs leading to the reduction of open time.     

Effect of 3 mg melatonin on jet lag syndrome in an 8-h eastward flight

In order to assess the effect of melatonin on jet lag a field study was undertaken. The process of re-entrainment of circadian melatonin rhythm was investigated in six subjects. Except during 24-h blood sampling, the subjects were exposed to natural zeitgeber (time giver) outdoors and given 3 mg melatonin at 23:00 h. The subjects were exposed to bright sunlight from 3000 to 12000 lx. All of them showed orthodromic re-entrainment with taking melatonin, while two out of the six did not show orthodromic re-entrainment without taking melatonin. Melatonin accelerated the rate of the re-entrainment of the circadian melatonin rhythm. Melatonin was useful to jet travel from Tokyo to Los Angeles.     

Automatic detection of rapid eye movements by discrete wavelet transform

In order to detect rapid eye movements (REM) automatically, the Discrete Wavelet Transform was applied to each 8-s segment of electrooculogram (EOG) data for 30 min of 8 h of normal sleep. The Haar function was used as an analysing wavelet because this function is similar to the REM waveform. By shifting the phase of the analysing wavelet by pi/4 of the function, 96% of REM could be detected. The artifacts caused by body movements could be detected simultaneously by this method. Computing time required for the detection of REM was only 11 s for 30 min EOG data.     

Effects of near-infrared low-level laser irradiation on microcirculation

BACKGROUND AND OBJECTIVE: Recently, there has been an increase in the clinical application of low-level laser irradiation (LLLI) in various fields. The present study was conducted to explore the effects of LLLI on microcirculation. STUDY DESIGN/MATERIAL AND METHODS: We investigated the effects of LLLI on rat mesenteric microcirculation in vivo, and on cytosolic calcium concentration ([Ca2+]i) in rat vascular smooth muscle cells (VSMCs) in vitro. RESULTS: LLLI caused potent dilation in the laser-irradiated arteriole, which led to marked increases in the arteriolar blood flow. The changes were partly attenuated in the initial phase by the superfusion of 15 microM L-NAME, but they were not affected by local denervation. Furthermore, LLLI caused a power-dependent decrease in [Ca2+]i in VSMCs. CONCLUSION: The circulatory changes observed seemed to be mediated largely by LLLI-induced reduction of [Ca2+]i in VSMCs, in addition to the involvement of NO in the initial phase.     

Thoracic epidural desmoplastic fibroma

Desmoplastic fibroma is a relatively uncommon tumor and rarely involves the spine. The authors describe a 20-year-old woman with a thoracic epidural desmoplastic fibroma treated by complete resection and posterior spinal fusion. Four years after surgery, neither the tumor nor clinical symptoms have recurred. Thus, complete resection is considered necessary to treat this tumor.     

Primary Mitral Valve Sarcoma in Infancy

Primary cardiac sarcoma is a rare tumor, found especially in children, particularly in the left side of the heart. This report describes a rare case of primary mitral valve sarcoma in a 7-month-old male infant with hemiparesis and heart murmur who underwent mitral valve replacement because of excessive invasion of the mitral valve by the tumor. The patient remains well, free of recurrence and cerebral metastasis, and without adjuvant therapy 18 months after the operation.     

Pharmacokinetic study of low- versus high-dose medroxyprogesterone acetate (MPA) in women

The present study was conducted to compare the pharmacokinetics (PK) of low-dose versus high-dose medroxyprogesterone (MPA) as a once-daily oral administration. Of 32 patients, all women, enrolled in this PK study, 18 received 600 mg MPA daily and 14 received 1200 mg daily. Detailed PK data were obtained on day 1 and after more than 4 weeks of MPA treatment. In addition, multiple data for the minimum steady-state concentration (Css min) were analyzed. The MPA serum concentrations were measured by high-performance liquid chromatography. Wide interpatient variability was found in the PK parameters obtained both on day 1 and after more than 4 weeks. There were no clear relationships between the oral dose and the MPA peak concentration (Cmax), area under the time versus concentration curve (AUC), or mean Css min. Weight gains of 10% or more were demonstrated more frequently in the high-dose group (P<0.01). Liver dysfunction (n=5) did not influence the PK of MPA. Five patients demonstrated extremely low AUC and Cmax (<10 ng/ml) values on day 1. Phenobarbital, dexamethasone and betamethasone were being taken concomitantly with the MPA each by one patient. The serum MPA concentrations were markedly increased after the discontinuation of phenobarbital in that patient, suggesting a drug interaction. At present we cannot recommend the high dose of MPA, except in clinical studies, from a PK or a pharmacodynamic points of view. Received: 2 May 1997 / Accepted: 13 October 1997