[The changes in cochlear blood flow and auditory brainstem response in the pressure-induced animal model of acoustic neuroma]

Changes in cochlear blood flow (CoBF) and auditory brainstem response (ABR) in a pressure-induced animal model of acoustic neuroma were examined. A suboccipital approach was used to expose the right cerebello-pontine angle in guinea pigs. Under surgical microscope, the bundle of nerves and vessels at the entrance of the internal auditory meatus was exposed without retraction. The two pressure points, one anterior to and the other posterior to the center of the bundle were separately compressed by a pressure probe (1mm in diameter). CoBF from the basal turn or second turn of the right cochlea was measured with a laser Doppler flowmeter. ABR was recorded from the electrodes placed on the vertex and the right mastoid process. With compression, the changes in CoBF and ABR were found in a total of 19 animals. We classified these changes into three types based mainly on CoBF. In type I (n = 9), an increase rather than a decrease of CoBF was noted, and an increase in the I-II inter-peak latency with a decrease in the amplitudes of wave II-IV in ABR were observed. Those changes were mainly attributed to the blockage of cochlear nerve. In type II (n = 6), CoBF was completely stopped and all waves of ABR disappeared during compression. This suggested the presence of cochlear ischemia. After relaxation of compression both CoBF and ABR recovered, but I-II inter-peak latency remained delayed. CoBF in type III (n = 4) decreased and then slowly recovered. In type III, all waves transiently disappeared, and wave I reappeared with recovery of CoBF. The changes in type III were caused by damage to both the artery and the nerve. In addition, the changes in CoBF and ABR were closely related to the pressure points. The changes in type I were often found in compression of the anterior pressure point, whereas the changes in type II are associated with the posterior pressuring point (p < 0.05). The results indicate that the cochlear nerve or the internal auditory artery is more susceptible to damage by compression of an anterior or posterior pressure point, and that the compression position is an important determinant in the type of auditory dysfunction and the degree of hearing loss.

[Cochlear ischemia and changes in compound action potentials in the guinea pig]

To determine the degree of decrease in cochlear blood flow (CoBF) which causes compound action potentials (CAPs) to disappear, a cochlear ischemic model was created by compressing the internal auditory artery in guinea pig. CoBF was measured with a laser Doppler flowmeter, and CAPs were recorded with an electrode placed on the round window membrane. The amplitude and latency of the N1 wave of CAPs changed as CoBF decreased. When CoBF diminished to as much as 70% below the original level, N1 disappeared. In this study, we also observed the N1 recovery process following CoBF reperfusion after 20 minutes of cochlear ischemia. N1 recovery in the group with an incomplete decrease in CoBF was better than in the group with a complete decrease in CoBF. These findings suggest that both the degree of compromise of CoBF and the duration of ischemia are important factors affecting the recovery of auditory function.

The role of nitric oxide in dizocilpine-induced impairment of spontaneous alternation behavior in mice

We investigated the role played by nitric oxide in the dizocilpine-induced impairment of both spontaneous alternation behavior in a Y-maze and of performance in a multiple-trial passive avoidance task in mice. Dizocilpine (0.1 mg/kg) impaired the spontaneous alternation behavior and the retention of passive avoidance without affecting acquisition in the multiple-trial passive avoidance task. NG-nitro-L-arginine methylester (L-NAME), an inhibitor of nitric oxide (NO) synthase, dose-dependently impaired the spontaneous alternation behavior, but had no effect on either the acquisition or retention of passive avoidance. NG-nitro-D-arginine methylester had no effect on either task. The inhibitory effect of L-NAME on the spontaneous alternation behavior was completely reversed by the coadministration of L-arginine. Pretreatment with L-arginine ameliorated the dizocilpine-induced impairment of spontaneous alternation behavior, but not the impairment of the retention of passive avoidance. S-Nitroso-N-acetylpenicillamine, a generator of NO, completely inhibited the dizocilpine-induced impairment of spontaneous alternation behavior. Finally, the impairment of spontaneous alternation behavior caused by dizocilpine was significantly diminished by pretreatment with dibutyryl cyclic GMP. These results suggest that, although N-methyl-D-aspartate receptors play a critical role in both spatial working memory and long-term memory processes assessed by spontaneous alternation behavior and the passive avoidance, respectively, different neuronal mechanisms may be involved in these two processes. Further, it is suggested that the NO/cyclic GMP system may play a role in spatial working memory.

[Anesthetic management of a pediatric patient with Cornelia de Lange syndrome]

We did anesthetic management on a pediatric patient with Cornelia de Lange syndrome presenting a peculiar look, variable physical deformities, and some growth and mental retardations. An 8-year-old male patient was scheduled for inguinal hernioplasty under general anesthesia. This patient had been suffering from dehydration for apodeisis and self-destructive tendency due to psychologic stress. Anesthesia was induced and maintained with sevoflurane and N2O in oxygen. The area of skin incision was infiltrated with 0.25 % bupivacaine for the purpose of post-operative analgesia, and as a result, psychologically and physically stable condition was obtained during post-operative periods. It is necessary to understand not only the patient's physical conditions but also mental ones in order to make the anesthetic management safer and more satisfactory.

Rhabdomyolysis following status asthmaticus

A case of rhabdomyolysis following an asthmatic attack is reported. A 71-year-old man was admitted because of wheezing and hypoxemia. Brown urine was present on admission. Although these symptoms completely disappeared with the treatment with aminophylline, salbutamol and corticosteroid, transiently elevated serum creatine phosphokinase and myoglobinuria were present. Rhabdomyolysis has rarely been reported in cases of bronchial asthma. This case represents an extremely rare case of rhabdomyolysis following status asthmaticus.

The phorbol 12-myristate 13-acetate (PMA)-induced oxidative burst in rat peritoneal neutrophils is increased by a 0.1 mT (60 Hz) magnetic field

Magnetic fields (MF) may affect biological systems by increasing free radical concentrations. To test this, we have investigated whether low frequency (60 Hz) low intensity (0.1 mT) MF can modulate the phorbol 12-myristate 13- acetate (PMA) induced respiratory burst in primed rat peritoneal neutrophils, followed in real time using the dye 2',7'-dichlorofluorescin (DCFH), which reacts with free radical-derived oxidants such as H2O2 (which is formed from the dismutation of superoxide) to become 2',7'-dichlorofluorecein (DCF), a highly fluorescent compound. In the presence of the MF, a 12.4% increase in the fluorescence signal was observed in PMA-stimulated neutrophils (n = 5, P < 0.02, 18 pairs of measurements). We believe this represents the first experimental observation of MF influencing events involving free radical species generated during signal transduction in living cells.

A new method of estimating the distribution of muscle fiber conduction velocities

A computer-assisted method of estimating the distribution of muscle fiber conduction velocities is described. An electrode array composed of 2 stimulating and 4 recording electrodes is used to record surface muscle action potentials (MAPs) in response to direct muscle stimulation. The velocity distribution and the single muscle fiber action potential (SFAP) are calculated from the recorded MAPs by an iterative method of estimation. The estimation is based on the assumption that the spatial orientation of each muscle fiber viewed from the recording electrodes is the same along the muscle fibers and a MAP is recorded as a linear summation of all SFAPs. The accuracy of this estimation is demonstrated using simulated MAPs. The method is also tested on MAPs containing simulated amplifier noise, stimulus artifact, and errors in distance between electrodes. Finally we applied this method to MAP recordings of the biceps brachii in 23 healthy subjects. The velocity distribution was successfully estimated in 20 cases. The average of the estimated distributions was smaller than that described by previous workers. The reasons for the difference are discussed.

Effects of RGH-2202 on behavioral deficits after focal cerebral ischemia in rats

We investigated the effects of RGH-2202 (posatirelin, (-)-(2S)-N-[(1S)-1-[[(2S)-2-carbamoyl-1-pyrrolidinyl[carbonyl]-3- methylbutyl]-6-oxopipecolamide), a thyrotropin-releasing hormone (TRH) analog, on behavioral changes during a chronic phase of focal ischemia in rats in comparison with the parent peptide. The left middle cerebral artery (MCA) was occluded under halothane anesthesia, and the subsequent behavioral changes were observed for 35 days. RGH-2202 (1, 3, and 10 mg/kg) and TRH (10 mg/kg) were given IP just after the operation and afterward once a day for 14 days. MCA-occluded rats exhibited neurologic symptoms including hemiplegia and abnormal posture and disturbance of passive avoidance learning during the entire 35-day observation period. The repeated treatment with either peptides improved the neurologic and cognitive deficits. In addition, a recovery from deficits was still advanced after discontinuation of the drug treatment. In these effects, RGH-2202 was about three times more potent than TRH. Neural tissue damage in drug-treated groups, measured by omega 3 binding site densities 35 days after MCA occlusion, was included to be less than that in the vehicle-treated group. These results suggest that appropriate treatment with RGH-2202 may be useful in the treatment of functional disturbances after focal cerebral ischemia.

Involvement of nitric oxide in phencyclidine-induced hyperlocomotion in mice

The present study was undertaken to investigate the involvement of nitric oxide (NO) in the behaviors induced by 1-(1-phenylcyclohexyl) piperidine (phencyclidine; PCP) in mice, using N(G)-nitro-L-arginine methyl ester (L-NAME), an inhibitor of NO synthase. PCP (1, 3, and 10 mg/kg s.c.) dose dependently induced hyperlocomotion and stereotyped behaviors, including sniffing, head movement, and ataxia, in mice. PCP also caused a marked deficit of motor coordination in mice, the effect being exerted in a dose-dependent manner. Although pretreatment with L-NAME (50 mg/kg i.p.) slightly enhanced the ataxia induced by PCP (3 mg/kg), it failed to modify other stereotyped behaviors and the lack of motor coordination induced by PCP (2 mg/kg). The hyperlocomotion induced by PCP (3 mg/kg) was significantly enhanced by L-NAME (5 and 50 mg/kg) and 7-nitro indazole (25 mg/kg), but not by D-NAME (50 mg/kg), a less active enantiomer of L-NAME. However, the behavioral changes induced by PCP, at the high dose, 10 mg/kg, were not enhanced by L-NAME and D-NAME. The enhancing effects of L-NAME on the PCP (3 mg/kg)-induced hyperlocomotion were significantly prevented by L-arginine (1 g/kg i.p.). However, D-arginine (1 g/kg i.p.) and L-lysine (1 g/kg i.p.) had no effect in this regard. These results suggested the involvement of central NO production in the mediation of PCP-induced behaviors, hyperlocomotion in particular, in mice.

Enhancement of immobility in a forced swimming test by subacute or repeated treatment with phencyclidine: a new model of schizophrenia

1. Immobility induced by forced swimming is well known as an animal model of depression. To develop an animal model for the negative symptoms of schizophrenia, in particular the depressive symptoms, the effect of phencyclidine (PCP) on immobility in the forced swimming test was investigated in mice, since PCP produces such negative symptoms in humans. 2. Repeated treatment with PCP (10 mg kg-1 day-1, s.c., once a day for 14 days) prolonged the immobility time in the forced swimming test 24 h after the final injection compared with saline treatment; the effect was not obtained by single or 5 treatments with PCP (10 mg kg-1, s.c.), or by repeated treatment with methamphetamine (0.5 and 1 mg kg-1 day-1, s.c., once a day for 14 days). 3. The enhancing effect of PCP (10 mg kg-1 day-1, s.c.) on the immobility persisted for at least 21 days after the withdrawal of the drug. 4. Haloperidol (0.3 and 1 mg kg-1, p.o.), ritanserin (3 and 10 mg kg-1, p.o.), risperidone (0.1-1 mg kg-1, p.o.), and clozapine (3 and 10 mg kg-1, p.o.) failed to attenuate the immobility induced by the forced swimming in mice repeatedly treated with saline when the drugs were administered 1 h before the forced swimming test. However, ritanserin (30 mg kg-1) and clozapine (30 mg kg-1) did attenuate this immobility. 5. The enhancing effect of PCP on the immobility was attenuated by ritanserin (3 and 10 mg kg-1, p.o.), risperidone (0.3 mg kg-1, p.o.), and clozapine (3 and 10 mg kg-1, p.o.), whereas haloperidol (0.3 and 1 mg kg-1, p.o.) had no effect. 6. These results suggest that the enhancement of immobility in the forced swimming test brought about by repeated PCP treatment could be used as a model of the negative symptoms, particularly the depression, of schizophrenia. This effect of PCP appeared to be mediated, at least in part, via 5-HT2A receptors.

Encapsulation of vasoactive intestinal peptide into liposomes: effects on vasodilation in vivo

The purpose of this study was to determine whether encapsulation of vasoactive intestinal peptide (VIP) into liposomes potentiated its vasorelaxant effects in vivo. Using intravital microscopy, we measured the diameter of second-order arterioles (53 +/- 1 microns) in the hamster cheek pouch before, during and after suffusion of VIP, liposomes and VIP encapsulated into liposomes for 7 min. We found that VIP (0.05, 0.1 & 1.0 nmol) induced significant, time- and concentration-dependent vasodilation (9 +/- 1%, 13 +/- 3% and 14 +/- 1% increase from baseline values, respectively; mean +/- SEM; n = 12; p < 0.05). Arteriolar diameter returned to baseline values within 1-4 min after suffusion was stopped. These effects were significantly potentiated when VIP (0.05, 0.1 & 1.0 nmol) was encapsulated into liposomes (26 +/- 6%, 38 +/- 7% and 34 +/- 3% increase from baseline values, respectively; n = 12; p < 0.05). In addition, arteriolar diameter returned to baseline values 5-13 min after suffusion was stopped. Suffusion of liposomes alone had no significant effects on arteriolar diameter (n = 12; p > 0.5). We conclude that encapsulation of VIP into liposomes potentiates and prolongs of its vasorelaxant effects in the peripheral microcirculation in vivo.

The presence and subtype of Epstein-Barr virus in B and T cell lymphomas of the sino-nasal region from the Osaka and Okinawa districts of Japan

BACKGROUND

Association between Epstein-Barr virus (EBV) and human malignancies, including sino-nasal lymphoma (SNL), has been suggested. EBV-associated malignancies have been reported to show distinct geographic distribution.

EXPERIMENTAL DESIGN

In the present study, the presence of an EBV genome and its subtypes (type A and B) were examined in 52 cases of sino-nasal lymphomas of B and T cell type collected from two areas of Japan: Osaka, situated on the mainland, and Okinawa, islands situated in a southwest part of Japan with a subtropical climate. Our previous epidemiologic study showed that the frequency of nasal T cell lymphoma was 3.5 times higher in Okinawa than in Osaka.

RESULTS

There were no prominent differences in age distribution or sex ratio between these two areas: age ranged 8 to 85 (median 54) years, with a male to female ratio of 1.26:1. Immunophenotypically, 27 cases were B cell type (20 Osaka, 7 Okinawa), 20 were T cell type (9 Osaka, 11 Okinawa), and 5 were undefined. By PCR, EBV positivity in throat washings of normal individuals in Osaka and Okinawa was 52 and 53%, respectively, with marked preponderance of subtype A in both areas. EBV genome was found in 6 of 15 cases (40%) and 4 of 5 cases (80%) of nasal B and T cell lymphomas in Osaka and in 3 of 7 cases (43%) and 7 of 7 cases (100%) in Okinawa, showing the different frequencies of positivity by immunophenotype but not by district. All but one patient had type A EBV. The in situ hybridization confirmed the results of PCR as positive signals in the nucleus of proliferating cells. Latent membrane protein-1 was expressed in 13 of 22 cases (59%).

CONCLUSIONS

These findings suggest that EBV, exclusively type A, might be a causative factor in sino-nasal lymphoma of not only T cell but also B cell type in Japan.

Relation between macro-EMG and muscle Uber conduction velocity

We investigated the relationship between macro-EMG and muscle Uber conduction velocity in the right biceps brachii in 5 normal subjects using a single-Uber macroelectrode and surface array electrodes. The macro-EMG signal and the surface electrode signals were triggered and averaged by the single-Uber action potential. The amplitude and area of the macro-EMG was correlated with the muscle Uber conduction velocity, suggesting that the macro-EMG can serve as a parameter of the size principle in both the clinical and research settings.

Role of nitric oxide in learning and memory and in monoamine metabolism in the rat brain

1. We investigated the effects of NG-nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide (NO) synthase, on the performance of rats in a radial arm maze and in habituation tasks, and on monoamine metabolism in the brain. 2. Daily administration of L-NAME (10-60 mg kg-1) resulted in a dose-dependent impairment of performance during the acquisition of the radial arm maze task, while it failed to affect performance in those rats that had previously acquired the task. 3. The rate of decrease in locomotor activity in the habituation task in the L-NAME-treated rats was significantly less than that in control rats. 4. NG-nitro-D-arginine methyl ester (D-NAME, a less active inhibitor of NO synthase) showed no effects in the above behavioural tasks. 5. NO synthase activity was significantly decreased in both the L-NAME and D-NAME-treated rats, with the magnitude of inhibition being greater in the L-NAME-treated animals. 6. The content of 5-hydroxyindoleacetic acid (5-HIAA) in the hippocampus and the 5-HIAA/5-hydroxytryptamine ratio in the hippocampus and cortex were significantly decreased in the L-NAME (60 mg kg-1)-treated rats compared with these values in the controls. 7. Striatal 3,4-dihydroxyphenylacetic acid (DOPAC) content was significantly increased in the L-NAME (60 mg kg-1)-treated rats compared with the values in the controls, while the DOPAC/dopamine ratio was not changed. 8. These results suggest that: (i) NO may play an important role in performance during the acquisition,but not retention, of the radial arm maze task, and (ii) that endogenous NO may be involved in the regulation of monoamine metabolism.

The use of intra-endometrial embryo transfer for increasing the pregnancy rate

It has been demonstrated previously that pregnancy can be achieved by the direct insertion of embryos into the endometrial stroma (intra-endometrial embryo transfer) of mice. In this study we evaluated whether intra-endometrial transfer resulted in a higher pregnancy rate than conventional embryo transfer. Mouse blastocysts (ICR strain), recovered on day 4 of pregnancy, were transferred into pseudopregnant day 2, day 3 and day 4 mice of the same strain; 1-, 2- and 8-cell embryos were also transferred into pseudopregnant day 4 mice. In intra-endometrial embryo transfer, a 27 gauge injection needle was inserted near the utero-tubal junction into the endometrial stroma and then removed; one blastocyst was transferred into each uterine horn with a glass micropipette. Conventional transfers were performed simultaneously as controls. The pregnancy rates and embryonic viability rates were evaluated 9 days after embryo transfer. Furthermore, the rates of live birth for intra-endometrial and conventional embryo transfers were compared when blastocysts were transferred into pseudopregnant day 4 uteri by both methods. In the transfer to pseudopregnant day 2 recipients, the pregnancy and embryonic viability rates were significantly higher (P < 0.01) in intra-endometrial [23.4 (11/47) versus 15.9% (15/94)] than in conventional embryo transfer [4.3 (2/46) versus 2.2% (2/92)]. In the transfer to pseudopregnant day 3 recipients, both rates were also higher (P < 0.01) in intra-endometrial [90.9 (40/44) versus 87.5% (77/88)] than in conventional transfer [67.4 (31/46) versus 64.1% (59/92)].(ABSTRACT TRUNCATED AT 250 WORDS)

[Clinical features of subacute interstitial pneumonia--clinico-pathological study based on open lung biopsy findings]

A clinico-pathological study was done to elucidate characteristic features of subacute interstitial pneumonia. The patients were four men and mine women, with a mean age of 60 years. In ten patients, the disease was idiopathic, three had collagen vascular disease, (and one was undergoing gold therapy for rheumatoid arthritis). The time interval between onset of symptoms and open lung biopsy was 80 +/- 40 days. Eleven patients had progressive dyspnea, seven had coughing, and only one complained of fever. Fine crakles were heard in ten patients. Mild increases in CRP were observed in all cases. Mild increases in total serum IgG concentration were observed in five of eight cases. Multiple patchy infiltration or diffuse interstitial shadows, located predominantly in the lower fields of both lungs were the characteristic chest roentgenographic findings. The average %VC was 62.7 +/- 17% and the average PaO2 was 68.3 +/- 10 Torr. Bronchoalveolar lavage was done in nine patients, and the mean total cell count was 16.5 +/- 10.2 x 10(4)/ml. A moderate increase in lymphocytes (30.8 +/- 18.6%) with a low CD4/8 ratio (0.48 +/- 0.57), a mild increase in neutrophils (6.2 +/- 9.1%), and a mild increase in eosinophils (2.3 +/- 3.7%) were observed. Pathologically, interstitial cellulo-fibrous changes associated with alveolar space closure due to organization of exudate were the main features. Patients were given steroid pulse therapy or oral steroids. The results were mild to marked improvements in chest roentgenographic findings and lung function.(ABSTRACT TRUNCATED AT 250 WORDS)

[High tissue concentration of 5-FU reduced local recurrence after administration of tegafur suppositories]

Forty-two patients with head and neck cancer were treated with tegafur suppository for 7 days preoperatively and clinical value of this treatment was assessed. In a group which indicated tumor tissue concentrations of 5-FU were more than 0.5 micrograms/g, local recurrence decreased in the period of postoperative observation for 42 months. A survival rate of this group was better than others. From these results, preoperative tegafur suppository treatment seemed to have a role in expectation of improvement of local control in head and neck cancer therapy.

Chylous cyst of the mesentery: US and CT diagnosis

We report a case of mesenteric chylous cyst diagnosed preoperatively by ultrasonography (US) and computed tomography (CT). Both demonstrated a unilocular cystic mass with a fluid-fluid level. The CT number of the two components indicated fat density and water density and with shaking or positional changes, the contents displayed miscibility. The tumor changed its position during hospitalization. Both features are considered to be quite diagnostic of this condition.