Observations of cavity polaritons in one-dimensional photonic crystals containing a liquid-crystalline semiconductor based on perylene bisimide units

We investigated the optical transmission properties of one-dimensional photonic crystal (1D-PC) microcavity structures containing the liquid-crystalline (LC) perylene tetracarboxylic bisimide (PTCBI) derivative. We fabricated the microcavity structures for this study by two different methods and observed the cavity polaritons successfully in both samples. For one sample, since the PTCBI molecules were aligned in the cavity layer of the 1D-PC by utilizing a friction transfer method, vacuum Rabi splitting energy was strongly dependent on the polarization of the incident light produced by the peculiar optical features of the LC organic semiconductor. For the other sample, we did not utilize the friction transfer method and did not observe such polarization dependence. However, we did observe a relatively large Rabi splitting energy of 187 meV, probably due to the improvement of optical confinement effect.

Activation of presynaptic 5-HT3 receptors facilitates glutamatergic synaptic inputs to area postrema neurons in rat brain slices

Whole-cell voltage-clamp recordings were performed to investigate the serotonergic modulation of neurotransmitter release onto rat area postrema neurons in vitro. The bath application of serotonin (5-HT; 50 microM) or phenylbiguanide (PBA; 50 microM), a potent 5-HT3 receptor agonist, increased the frequency of spontaneous excitatory postsynaptic currents (sEPSCs) or miniature EPSCs (mEPSCs) in 35 of 83 neurons (42%). These increases occurred in all electrophysiological cell classes. No cells exhibited a decrease in EPSC frequency. The majority of responding cells showed no inward currents during the application of serotonergic agonists (n = 34/35). However, the amplitude of mEPSCs was increased in 11/11 cells with 5-HT or 3/11 cells with PBA. ICS-205,930, a potent 5-HT3 receptor antagonist, markedly suppressed the 5-HT-induced facilitation of sEPSCs (n = 5) or mEPSCs (n = 5). An increase in the frequency of mEPSCs after PBA exposure was found, even with media containing Cd2+ (50 microM) or zero Ca2+. mEPSCs and evoked EPSCs were completely blocked in media containing the non-NMDA ionotropic receptor antagonist, CNQX (10 microM), indicating that EPSCs were glutamate events. These results suggest that glutamate release is increased in the area postrema by presynaptic 5-HT3 receptor activation. Furthermore, we present evidence that 5-HT3 receptor activation may be able to directly release glutamate from terminals, bypassing a requirement for voltage-dependent calcium entry into terminals. Such a mechanism may contribute to the chemosensitive function of area postrema neurons.

Functional Electrical Stimulation (FES) for spinal cord injury

Restoration of respiratory motion by stimulation of the phrenic nerve was investigated. Respiratory motion was restored successfully by introducing a breathing pacemaker to a patient with respiratory disturbance due to upper cervical spinal cord injury. Breathing pacemakers are considered to be more similar to physiological conditions compared to mechanical ventilators. Although the system is very expensive, its cost effectiveness may be excellent, provided that it can be used for long hours each day over an extended period. The system is effective in improving patient QOL because it dramatically increases patient mobility. From these findings, it is concluded that breathing pacemakers should be used more frequently in Japan, and that various forms of support are necessary to cope with economic and other concerns.

Propofol suppresses a hyperpolarization-activated inward current in rat hippocampal CA1 neurons

We examined the effect of propofol and thiopental, intravenous anesthetics, on the hyperpolarization-activated inward current (I(H)), whose functional role on the neuronal activity has been evaluated. Whole-cell recordings of I(H) evoked by hyperpolarizing step pulses were taken from hippocampal CA1 neurons in rat brain slices. Propofol reduced I(H) current in a dose-dependent manner. However, thiopental had no significant effect on the activation of I(H). According to the functional role of I(H), the suppression of I(H) should result in a reduction of neuronal activity. We suggest that the effectiveness of propofol as an anticonvulsant or an antiemetic is associated with the blockade of the I(H) channel.

Effects of left ventricular assist device on cardiac function: experimental study of relationship between pump flow and left ventricular diastolic function

The left ventricular assist device (LVAD) with centrifugal pump has two characteristics. One is a pump flow wave of the centrifugal pump, consisting of the pulsatile flow of the native heart and the nonpulsatile flow of the centrifugal pump. The other is that the centrifugal pump fills from the native heart not only in the systolic phase, but also in the diastolic phase. In the case of the apex outlet LVAD with centrifugal pump, blood flows from the left atrium through the left ventricle to the pump. Pump flow is regulated by preload, and preload is regulated by diastolic hemodynamics. The aim of this study is to analyze the relationship between pump flow and the diastolic hemodynamics of the native heart. Ten anesthetized intact pigs were studied after placement of an LVAD. Data were recorded with the LVAD off (control) and the LVAD on. The assist rate was changed to 25%, 50%, and 75%. The indexes of left ventricular (LV) diastolic function included LV myocardial relaxation (time constant of isovolumic pressure decay [Tau] and maximum negative dP/dt [LV dP/dt min]) and LV filling (peak filling rate [PFR], time to peak filling rate [tPFR], and diastolic filling time [DFT]). Stroke volume decreased significantly in 75% assist. LV end-systolic pressure decreased significantly in 50% and 75% assist. LV end-diastolic volume decreased as assist rate increased, but there were no significant changes. Stroke work decreased significantly in 50% and 75% assist. LV dP/dt min decreased significantly in 50% and 75% assist. Tau prolonged as assist rate increased, but there were no significant changes. DFT shortened significantly in 75% assist. PFR increased significantly in 75% assist. tPFR shortened significantly in 50% and 75% assist. In this study, LV relaxation delayed as an increasing of pump assist rate, but it suggested a result of reduction of cardiac work. Also, it was suggested that LVAD increases the pressure difference between the left atrium and the left ventricle in the diastolic phase. This phenomenon is due to the filling of the left ventricle. In this study it was suggested that as pump assist rate increases, it is more effective to keep cardiac function in the diastolic phase.

Intravenous anesthetics inhibit nonadrenergic noncholinergic lower esophageal sphincter relaxation via nitric oxide-cyclic guanosine monophosphate pathway modulation in rabbits

BACKGROUND

Nonadrenergic noncholinergic (NANC) nerves have important roles in the regulation of the lower esophageal sphincter (LES) motility and function. The effects of thiopental, ketamine, and midazolam on NANC LES relaxation were investigated.

METHODS

The isometric tension of circular muscle strips from Japanese White rabbits was examined. The NANC relaxation was induced by KCl (30 mM) in the presence of atropine (3 x 10(-6) M) and guanethidine (3 x 10(-6) M). The modifications of the NANC and sodium nitroprusside (SNP; 10(-5) M)-induced relaxation by the anesthetics were examined. The content of 3',5'-cyclic guanosine monophosphate (cGMP) was measured by radioimmunoassay.

RESULTS

The KCl-induced relaxation was abolished by pretreating with tetrodotoxin (10(-6) M). The NANC relaxation was inhibited in the presence of N(G)-nitro-L-arginine (L-NNA; 3 x 10(-5) M), methylene blue (10(-6) M), apamin (10(-7) M), and glibenclamide (10(-5) M). The SNP-induced relaxation was inhibited by methylene blue but was not affected by tetrodotoxin, L-NNA, apamin, or glibenclamide. Ketamine (EC50 = 8.8 x 10(-5) M) and midazolam (EC50 = 4.8 x 10(-6) M) suppressed the NANC response in a concentration-dependent manner, leaving SNP-induced response unchanged. Thiopental altered neither of the relaxations. cGMP content was decreased in the presence of ketamine and midazolam.

CONCLUSION

The NANC relaxation was mediated by nitric oxide and by low-conductance calcium- and adenosine triphosphate-sensitive potassium channels of smooth muscle. The modulation of the nitric oxide-cGMP pathway was related, at least in part, to the inhibitory actions of ketamine and midazolam on the NANC LES relaxation.

Role of parabrachial nucleus in submandibular salivary secretion induced by bitter taste stimulation in rats

When rats lick a bitter taste solution such as quinine-hydrochloride, they secrete profuse amounts of saliva. The salivation has a higher flow rate than that induced by other qualities of taste stimulation: sweet, salty, and sour. The present study is aimed to clarify the neural mechanism of the quinine-evoked salivation by means of behavioral, neuroanatomical, and electrophysiological experiments. Behaviorally, submandibular salivary secretion and rejection behavior (gaping) were observed in normal rats, as well as in rats chronically decerebrated at the precollicular level. In chronically decerebrate rats, these quinine-evoked reactions were strongly suppressed by destruction of the medial part of the parabrachial nucleus, including the so-called taste area, and ventral part of the parabrachial nucleus, including the pontine reticular formation. Neuroanatomical study using a retrograde tracer, Fluoro-gold, revealed that the neurons sending their axons to the superior salivatory nucleus, parasympathetic secretory center, were located mainly in the pontine reticular formation ventral to the parabrachial nucleus, not in the parabrachial taste area. Extracellular neural activity was recorded from the parabrachial region in decerebrate rats, and responsiveness to taste stimulation, jaw movements, and electrical stimulation of the superior salivatory nucleus was examined. Neurons responsive to both taste stimulation and antidromic stimulation of the superior salivatory nucleus were found in the pontine reticular formation ventral to the parabrachial nucleus, which responded well to quinine and HCl taste stimuli. Neurons in the parabrachial taste area could respond to four qualities of taste stimulation, but not to antidromic stimulation of the salivary center. These results suggest that aversive taste information from the parabrachial taste area reaches the salivary secretory center via the reticular formation ventral to the parabrachial nucleus.

Propagation of synchronous burst discharges from entorhinal cortex to morphologically and electrophysiologically identified neurons of rat lateral amygdala

Intracellular and field potential recordings were taken from the lateral nucleus of the amygdala in a rat horizontal brain slice preparation that included hippocampal formation. Pyramidal cells comprised the majority of labeled cells (77%). Electrophysiological classification based on hyperpolarizing or depolarizing afterpotentials subdivided both the pyramidal and non-pyramidal cell classes, although pyramidal cells tended to have hyperpolarizing afterpotentials (70%) and non-pyramidal cells tended to have depolarizing afterpotentials (63%). Synchronous population bursts were triggered with single extracellular stimuli in the deep layers of entorhinal cortex. These events propagated from deep layers of entorhinal cortex into the lateral nucleus of the amygdala. Latencies were consistent with a direct entorhinal to amygdala projection. Individual lateral nucleus neurons exhibited responses ranging from a long burst response that included an initial period of 200 Hz firing and a tail of gamma frequency firing lasting over 100 ms (grade 1) to an epsp with no firing (grade 4). Half of pyramidal cells responding to events initiated in entorhinal cortex were found to receive epsps strong enough to trigger firing. Only one stellate neuron fired in response to entorhinal stimulation. Excitatory postsynaptic responses included NMDA and non-NMDA receptor mediated components. We demonstrate that synchronous population events can propagate from entorhinal cortex to the lateral nucleus of the amygdala and that pyramidal neurons of the lateral nucleus are more common targets than stellate neurons. We conclude that other synchronous events such as sharp waves and interictal spikes can spread from entorhinal cortex to amygdala in the same manner.

MRI of disseminated developmental dysmyelination in Fukuyama type of CMD

Whether the pathologic origin of white matter lesions in Fukuyama type of congenital muscular dystrophy (FCMD) is delayed myelination or dysmyelination is a controversial issue. This study investigated pathologic distribution in white matter with heavily T(2)-weighted images using fluid-attenuated inversion recovery (FLAIR) pulse sequence. For detection of abnormal white matter lesions, FLAIR images were approximately twice as sensitive as T(2)-weighted images and five times as sensitive as T(1)-weighted images of spin echo sequence. The distribution of the white matter lesions was disseminated and not correlated with cortical disarrangement. The distribution was not consistent with delayed myelination. These findings support the evidence found using in vitro proton-NMR spectroscopy that the pathologic origin of white matter lesions is dysmyelination. When conventional magnetic resonance imaging is used, masked white matter lesions are easy to misidentify as delayed myelination instead of disseminated developmental dysmyelination. The lesions in the white matter of FCMD are masked because of brain development.

[A case report of treatment for tracheal fistula after radical esophagectomy]

We report our experience of the treatment of a 60-year-old man with upper tracheal fistula which developed on the 11th day after radical surgery for esophageal cancer. Primary treatment to close the fistula was unsuccessful, resulting in the involvement of empyema due to infection. Controlled ventilation with T-tube and drainage through a chest tube for 2 months lead to depuration of the thoracic cavity. As a strategy for secondary closure of the fistula, fenestration was performed on the 87th day postoperatively. The patient's overall condition improved thereafter and closure was being considered. However, the patient died on the 116th day postoperatively due to supervenient aspiration pneumonia. Thus, long-term controlled ventilation with a T-tube was beneficial for the treatment of central airway injury.

Activity of neurons in the nucleus of the solitary tract of rats: effect of osmotic and mechanical stimuli

Patch-clamp recordings were used to examine the osmosensitivity and mechanosensitivity of neurons in the caudal part of the nucleus tractus solitarius in coronal slices from rat brain. Firing rates and membrane potentials were measured as slices were exposed to perfusate which varied in its osmolality and/or sodium concentration. In all cells tested, the responses to change in the sodium concentration of perfusate were duplicated by osmolality changes of sucrose or mannitol. When nucleus tractus solitarius cells were tested with changes in pressure applied via the pipette, responses to positive or negative pressure paralleled their responses to osmotic stimulation. We suggest that a mechanosensitive receptor exists on osmosensitive neurons within the nucleus tractus solitarius, and this receptor may be responsible for changes in the firing rate and membrane potential which occur in the nucleus tractus solitarius neurons.

Sequential chemoimmunotherapy with cisplatin, interferon-beta and interleukin-2 inhibits the growth of B16-F1 melanoma in syngeneic mice

Sequential combinations of chemotherapy with biological response modifiers has recently been evaluated as systemic treatment for patients with advanced melanoma. The response rates of the chemoimmunotherapy were reported to be higher than conventional treatment using chemotherapy or biological agents alone. To investigate the effectiveness of such chemoimmunotherapy, we evaluated the antitumour effect of sequential chemoimmunotherapy in vivo using a B16 mouse melanoma system. In this sequential regimen, administration of cisplatin (CDDP) was followed by interferon-beta (IFNbeta) and interleukin-2 (IL-2). This combination therapy synergistically inhibited the growth of B16-F1 melanoma and prolonged the survival of mice bearing B16-F1. In contrast, this therapy did not show any antitumour effect on B16-F10 melanoma. The exact mechanism of the antitumour effect is not clear, but the following results were noted: no synergistic effect of this therapy was detected in nude mice, neutralizing anti-IFNgamma antibody significantly blocked the antitumour effect of this therapy, and the number of apoptotic melanoma cells was significantly increased in melanoma tissues removed from mice treated with this therapy. These results demonstrated the potent immunological antitumour effect of this sequential chemoimmunotherapy.

Application of the cell block method, utilizing mount quick mounting medium

Our objective was to determine the applicability of cell transfer and cell block methods using Mount Quick (Daido Sangyo, Saitama, Japan) mounting medium (MQ) for hematoxylin-eosin (H&E) and immunohistochemical staining of several limited amounts of biological materials in slide preparations. The materials investigated were histopathologically confirmed malignant mesotheliomas (pleural effusions) and malignant lymphomas, a malignant melanoma, and an amelanotic melanoma in sealed slides. Monoclonal antibodies against carcinoembryonic antigen (CEA), epithelial membrane antigen (EMA), cancer antigen 125 (CA-125), vimentin, thrombomodulin (TM), cytokeratin, UCHL-1, L-26, melanoma-specific antigen (HMB45), and S-100 protein (S-100) were applied in the investigation. The malignant mesotheliomas were found to be positive for EMA, cytokeratin, vimentin, TM, and CA-125, and negative for CEA, with no differences being observed in findings from direct contact preparations. Using T-cell-type malignant lymphomas for immunohistochemistry, UCHL-1 positivity and L-26 negativity were clearly demonstrated. The malignant melanoma and amelanotic melanoma materials stained strongly for HMB45 and S-100. Cell transfer employing MQ is a suitable approach for immunohistochemical investigations of limited materials. In addition, cell blocks derived from MQ-embedded smears can be used for both H&E and immunohistochemical staining. Diagn. Cytopathol. 2000;22:117-119.

Re-entrant activity in a presubiculum-subiculum circuit generates epileptiform activity in vitro

The retrohippocampal cortices form the transition between neocortex and the hippocampus. Area CA3 of the hippocampus and the entorhinal cortex (EC) of the retrohippocampal region are established as brain regions that generate epileptiform activity. Interictal activity generated in EC consists of a primary population burst followed by multiple afterdischarges. The presubiculum is similar to EC in its six-layered structure, but lacks a columnar circuitry that the EC possesses. Isolated presubicular tissue cannot generate afterdischarges and isolated subicular tissue generates no spontaneous activity under some conditions. We report epileptiform activity in combined presubiculum-subiculum slices that consists of synchronous population bursts and multiple afterdischarges. Intracellular and field potential recordings reveal two re-entrant paths for interaction of presubicular and subicular neurons. We demonstrate a deep presubicular input to subiculum and separate return paths from subicular bursting neurons onto deep and superficial layer pre-/parasubicular neurons. Recordings from subicular cell apical dendrites showed repetitive burst firing during sustained depolarizing current injection. We conclude that re-entrant activity in a presubiculum-subiculum circuit generates epileptiform activity in both regions. Presubicular inputs to subiculum depolarize apical dendrites which can then burst repetitively. These bursts are transmitted back to the presubiculum. We suggest that iterations on this circuit act to prolong the dendritic depolarization of subicular bursting neurons and to entrain the activity across subicular cells resulting in multiple afterdischarges.

Noxious tooth pulp stimulation suppresses c-fos expression in the rat hippocampal formation

Changes in the expression of immediate early gene c-fos by noxious mechanical stimulation to the mandibular incisor pulp of rats were immunohistochemically examined in the hippocampus (Ammon's horn and dentate gyrus) and the retrohippocampus (subiculum, presubiculum, parasubiculum and entorhinal cortex). The highest control levels were found in subiculum, CA1, dentate and deep medial entorhinal cortex. Lower, but substantial levels were present in the other areas. Whereas weak dentinal stimulation caused increases in c-fos expression in some regions which were not statistically significant, strong tooth pulp stimulation caused a bilateral decrease in c-fos expression in every region except contralateral subiculum. These decreases reached statistical significance in superficial layer parasubiculum bilaterally (p<0.01), bilateral CA1 and ipsilateral side of superficial layer of medial entorhinal cortex (p<0.05). We suggest that inhibitory circuitry in hippocampal formation regions may be activated by peripheral noxious somatosensory inputs and this change in activity is accompanied by a change in the expression of the immediate early gene, c-fos.

Pleiotrophin as a Swiss 3T3 cell-derived potent mitogen for adult rat hepatocytes

Rat parenchymal liver cells were cultured in the presence of lethally treated Swiss 3T3 cells. This co-culture allowed hepatocytes to produce colonies containing more than 300 cells in 30 days. Hepatocytes in colonies appeared morphologically normal and some of them were suggested to have bipotental differentiation capacity. The initial growth stimulatory activity of the feeder cells was replaceable with their conditioned medium (CM). Biochemical analysis of an active principle in the 3T3 cell-CM identified pleiotrophin. Pleiotrophin purified from the 3T3 cell-CM, recombinant human pleiotrophin, chemically synthesized human pleiotrophin, and midkine promoted the growth of hepatocytes as well. Reverse transcription-polymerase chain reaction clearly showed that the synthesis of mRNA of pleiotrophin was stimulated in the regenerating liver induced by either partial hepatectomy or the treatment with d-galactosamine, strongly suggesting a biological significance of pleiotrophin in the proliferation of hepatocytes in vivo. From these results we concluded that pleiotrophin is a new potent growth factor for adult parenchymal hepatocytes. This study indicates the importance of mesenchymal stimulation for the growth of adult rat hepatocytes.

Presence of nuclear grooves in endometrial cytology

Although the presence of nuclear grooving in papillary carcinomas of the thyroid has been well-described, so far the attention paid to similar structures in endometrial cell samples has been limited. In order to investigate the occurrence of nuclear grooves in endometrial specimens from patients with various pathologic conditions of the endometrium, we compared their appearance with papillary thyroid cancers. A total of 10 cases was studied (age range, 40-72 yr), all cases demonstrating nuclear grooves. In each case, 10 random high-power fields (HPFs) were investigated, and the numbers of fields in which nuclear grooving could be seen were recorded. Nuclear grooves were observed in 3-36 of each HPFs and were more often observed in atypical endometrial cells than in their normal-appearing counterparts; however, these nuclear alterations were thought to be nonspecific findings.

Properties of gamma-frequency oscillations initiated by propagating population bursts in retrohippocampal regions of rat brain slices

1. In the hippocampal formation in vivo, brief periods of gamma-frequency activity follow population bursts called sharp waves. The approximately 200 Hz activity of the sharp wave itself may serve to enhance synaptic connections and the approximately 40 Hz gamma activity has been offered as a mechanism for solving the 'binding' problem. We describe epochs of gamma-frequency activity which follow population spikes evoked by low frequency repetitive extracellular stimuli in retrohippocampal neurons of horizontal rat brain slices. 2. gamma-Frequency activity recorded intracellularly from deep layer neurons of entorhinal cortex, presubiculum and parasubiculum consisted of one action potential correlated with each of the three to five gamma cycles recorded with a proximate field potential electrode. A minority of cells exhibited only sub-threshold gamma-frequency membrane potential oscillations (ranging from 5 to 10 mV). No cells fired more than one spike per gamma cycle under any conditions. 3. The range of synchrony varied from individual cells which showed gamma-frequency firing without corresponding oscillations in close field recordings to field potential recordings of oscillations which were well correlated across regions. The lead or lag between any two retrohippocampal regions was in the direction of the conduction delay for the primary population spike, but typically was less, and approached zero milliseconds for some cycles in most cells. The level of synchrony was stable for particular stimulating conditions (intensity, stimulation rate, stimulus location). 4. The duration of the period of gamma activity had the duration of a slow depolarizing potential which was mediated by NMDA receptor activation. NMDA receptor antagonists or low concentrations of AMPA receptor antagonists reduced the duration of, or completely abolished the slow potential, thereby eliminating the gamma portion of the evoked response. 5. gamma-Frequency firing was eliminated by the GABAA receptor antagonist picrotoxin but small (< 5 mV) membrane potential oscillations remained after focal picrotoxin applications, and these exhibited the voltage dependence of EPSPs. Bath application of thiopental lowered the frequency of gamma oscillations, confirming the involvement of GABAA receptors. 6. The GABAB receptor antagonist 2-hydroxy-saclofen appeared to enhance the gamma activity by increasing the duration of the gamma epoch and increasing the amplitude of individual gamma cycles in field potential recordings. These saclofen-induced cycles were, however, less well synchronized across regions. 7. We show that synchronous gamma (40-100 Hz) activity follows population bursts by deep layer retrohippocampal neurons in undrugged slices from rat brain. Responses from medial entorhinal, parasubicular or presubicular cells were not distinguishable. These events can be initiated by a propagating population spike. We suggest that an NMDA receptor mediated depolarization enables the network of deep layer retrohippocampal neurons to oscillate by providing a sustained excitation, the duration of which determines the duration of the gamma episode. gamma-Frequency firing is primarily the result of GABAA receptor dependent inhibition during this period of sustained depolarization. Recurrent excitation appears to be inconsequential for principal cell firing, but may contribute to interneuron firing.

Induction of immediate-early genes c-fos and zif268 in the subnucleus oralis by noxious tooth pulp stimulation

c-fos and zif268 expression were assessed by immunocytochemistry for c-Fos and Zif268 proteins in the sensory trigeminal nuclear complex following noxious mechanical stimulation of the mandibular incisor pulp of rats. Marked up-regulation of both immediate early genes was observed in the subnucleus oralis ipsilateral to the stimulation. Cavity preparation of the dentine without reaching the pulp did not cause significant up-regulation detectable by immunocytochemistry. These results provide evidence that noxious dental signals reach the ipsilateral subnucleus oralis and up-regulate the transcription of immediate early genes c-fos and zif268.

GABA receptor-mediated post-synaptic potentials in the retrohippocampal cortices: regional, laminar and cellular comparisons

Inhibitory post-synaptic potentials (IPSPs) were studied in neurons of presubiculum, parasubiculum and medial entorhinal cortex in horizontal slices from rat brains. Isolated IPSPs were evoked by extracellular electrical stimuli in the presence of glutamate receptor antagonists. Cellular morphology was identified using Neurobiotin labeling. IPSPs were compared: (a) across morphological cell types, (b) across laminae within regions, and (c) across regions. IPSPs were visible in stellate and pyramidal cells from layers II, III, and V of all retrohippocampal areas during bath application of glutamate antagonists. Qualitative and quantitative differences in IPSPs were only found when comparing responses by superficial layer II, III cells to responses by deep layer V cells. Responses by stellate and pyramidal cells within the same or adjacent layers did not differ, nor did responses differ from region to region. All cell types exhibited an early hyperpolarizing response. The majority (85%) of superficial layer cells in all regions, regardless of cell shape, exhibited a second hyperpolarizing component. Fewer (50%) deep layer cells exhibited the late peak with similar long latencies. IPSPs were typically larger in superficial layer cells. IPSPs were comprised of GABAA and GABAB (gamma-aminobutyric acid) receptor-mediated components. With repetitive stimulation, the peak amplitude of the GABAA receptor-mediated component decreased with successive stimuli, but stabilized during the first five or fewer stimuli to a level that did not vary with stimulation frequency. The GABAB receptor-mediated component also stabilized, but the final amplitude appeared to decrease as the stimulation frequency increased. With high-frequency repetitive stimulation, both components of the IPSP showed summation. We conclude that the most meaningful distinction for IPSPs among retrohippocampal neurons is a laminar distinction, between superficial and deep layer neurons, and not one across cell shape or retrohippocampal subregion. These laminar differences can contribute to synchronous activity by deep layer neurons and restrict the activity of superficial layer neurons.

Effect of 4-methylumbelliferone on cell-free synthesis of hyaluronic acid

Human skin fibroblasts were cultured in the presence of 0.5 mM 4-methylumbelliferone for 12 h, and cell-free synthesis of hyaluronic acid was performed using membrane-rich fraction from the cells. The preincubation of the cells with 4-methylumbelliferone reduced hyaluronic acid synthesis to 15% of that of non-preincubated cells, although its chain length was not changed. On the other hand, without preincubation of the cells with 4-methylumbelliferone, hyaluronic acid synthesis was not changed even when 4-methylumbelliferone was added directly to the reaction mixture. These results suggest that 4-methylumbelliferone represses the expression of hyaluronic acid synthase on the cell surface.

Presubicular and parasubicular cortical neurons of the rat: functional separation of deep and superficial neurons in vitro

1. The presubiculum and parasubiculum are retrohippocampal structures bordered by the subiculum and medial entorhinal cortex. Deep layer (IV-VI) neurons from this region exhibit stable synaptically triggered burst behaviour which distinguishes them from superficial layer (I-III) cells. This functional separation was examined with intracellular and field potential recordings from horizontal slices of rat brain. Neurobiotin labelling and rapid Golgi techniques were used to obtain anatomical evidence of axonal trajectories. 2. Extracellular stimulation of the subiculum, deep medial entorhinal cortex or superficial pre- or parasubiculum caused, in deep layer cells only, a short latency burst discharge which could be followed by one or more after-discharges. Bursts appeared after repetitive stimulation and were stable for the life of the slice. Each event was supported by giant excitatory postsynaptic potentials (EPSPs). Events were similar whether they were evoked in horizontal slices or slices cut perpendicular to the horizontal plane. 3. Bath application of the NMDA receptor antagonist 3-[2-carboxypiperazin-4-yl]-propyl-1-phosphonic acid (CPP; 5 microM) elevated the threshold for evoking the giant EPSP. Higher concentrations (10-15 microM) reduced the amplitude and duration of the giant EPSP. Bath application of the AMPA receptor antagonist beta-cyano-7-nitroquinoxaline-2,3-dione (CNQX; 5 microM) eliminated the evoked EPSP. 4. In intact slices, superficial layer neurons of pre- and parasubiculum could exhibit EPSPs coincident with bursts recorded in the deep layers. However, in isolated subsections of horizontal slices or in 'vertical slices', both of which contained only pre- and/or parasubiculum, evoked or picrotoxin-induced bursts occurred only in deep layer cells. Superficial layer cells in these subsections showed no response to deep layer events. 5. Antidromic population spikes confirmed projections from superficial cell layers of pre- and parasubiculum down to their deep cell layers. Reciprocal antidromic responses were absent. 6. Axons of superficial layer stellate and pyramidal cells had horizontal collaterals and at least one ascending and one descending collateral. Branches of the descending collaterals were given off in layer V and some axons were found to reach the angular bundle. Axons of deep layer stellate and pyramidal cells also had horizontal collaterals and descending collaterals which could be traced to the angular bundle. One ascending axon collateral was found among the thirty-one deep layer cells examined morphologically. 7. We conclude that the deep layer cells of the presubiculum and parasubiculum are richly interconnected with excitatory synapses. These interconnections can generate giant excitatory synaptic potentials that support the bursting behaviour exhibited by these neurons. Any of the excitatory inputs to deep layer cells can trigger the population bursts and specific inputs from entorhinal cortex produce the after-discharges. Further, connections between superficial and deep layer cells appear to be almost exclusively in the direction of superficial to deep. The absence of significant ascending input can account for the functional separation of superficial and deep layer neurons of presubiculum and parasubiculum.

Regulation of hyaluronate metabolism by progesterone in cultured fibroblasts from the human uterine cervix

The effects of progesterone, dehydroepiandrosterone sulfate and 17beta-estradiol on the synthesis and degradation of hyaluronate were investigated using human uterine cervix fibroblasts. The cells were incubated with [3H]glucosamine in the presence of the hormones and then [3H]hyaluronate was isolated from the medium. The changes in the radioactivity of [3H]hyaluronate showed that progesterone suppressed hyaluronate synthesis by 22% of the control levels, while dehydroepiandrosterone sulfate and 17beta-estradiol enhanced it by 22% and 12% of the control levels, respectively. Furthermore, progesterone induced degradation of high-molecular-weight [14C]hyaluronate into low-molecular-weight hyaluronate (Mr approximately 40000). These results suggest that in cultured fibroblasts from the human uterine cervix progesterone converts hyaluronate metabolism from the synthesis phase to the degradation phase.

Exaggerated C-fiber activation prevents peripheral nerve injury-induced hyperinducibility of c-Fos in partially deafferented spinal dorsal horn

Dorsal horn neurons chronically deafferented by peripheral nerve injuries acquire hypersensitivity to noxious input from outside the original receptive field. This study examines the effect of electrical nerve stimulation at the time of injury on such injury-induced hypersensitivity. The medial 3/8 of the dorsal horn laminae I/II around the junction of 4th and 5th lumbar segments (the tibial territory) was deafferented by transection of the ipsilateral tibial nerve in rats. At 2 days or 3 weeks postinjury, the hindpaw was injected with formalin to induce c-fos. At 2 days, neurons with induced c-Fos protein-like immunoreactivity (fos-neurons) were largely confined in the lateral 5/8 of laminae I/II (the peroneal and hip, thus P and H territory). At 3 weeks, fos-neurons significantly increased in the deafferented tibial territory. A similar increase was also noted in the P and H territory. Thus the dorsal horn neurons exhibited c-fos hyperinducibility, an indication of hypersensitivity. Electrical stimulation with a train of 150 shocks (10 V, 2 ms) of the proximal nerve stump immediately after transection prevented the c-fos hyperinducibility. The effect was greater with the stimulation frequency of 0.5 Hz than 0.1 Hz or 10 Hz. The stimulation had no effect on the c-fos inducibility at 2 days postinjury.

Presubicular and parasubicular cortical neurons of the rat: electrophysiological and morphological properties

Intracellular recordings and Neurobiotin-injection were used to examine the electrophysiology and morphology of presubicular and parasubicular cortical neurons in horizontal slices from rat brains. Evoked responses were obtained by stimulation of subicular and entorhinal cortices. Stellate cells were recorded in layers II and V of presubiculum and parasubiculum. Superficial layer cells had spiny dendrites that were found to reach layer I. Deep layer cells had sparsely spiny dendrites or dendrites without spines that did not reach past layer IV. Pyramidal cells were recorded in layers III and V of presubiculum and layers II and V of parasubiculum. Superficial layer cells had spiny dendrites that were found to reach layer I. Deep layer cells had sparsely spiny dendrites or dendrites without spines that could reach layer II. Electrophysiologically, stellate and pyramidal cells were similar to one another, regardless of cell layer, exhibiting repetitive single spiking in response to depolarizing current injection. No cells were found to burst in response to current injection. While there were subtle electrophysiological differences among the cell types, stellate cells were more similar to pyramidal cells from the same or adjacent layers than to other stellate cells from more distant layers. Similarly, pyramidal cells were electrophysiologically more similar to nearby stellate cells than to other distant pyramidal cells. Cells of all layers responded to subicular stimulation with a short latency (< 9 ms), excitatory postsynaptic potential. Superficial layer cells responded at short (< 9 ms), longer (10-20 ms) and very long latencies (> 20 ms) to stimulation of superficial layers of medial entorhinal cortex. Deep layer cells responded at short latencies (< 9 ms) to stimulation of deep layers of medial entorhinal cortex. Many cells responded to both subicular and entorhinal inputs. Both pyramidal and stellate cells in the deep layer of pre/parasubiculum could exhibit population bursting behavior in response to stimulation of subiculum or entorhinal cortex. The results define the cellular morphology and basic electrophysiology of presubicular and parasubicular neurons of the rat brain as a step toward understanding the physiology of the retrohippocampal cortices.

Are breaches in the glia limitans the primary cause of the micropolygyria in Fukuyama-type congenital muscular dystrophy (FCMD)? Pathological study of the cerebral cortex of an FCMD fetus

A light and electron microscopic study of the brain of an 18-week fetus with a prenatal genetic diagnosis of Fukuyama-type congenital muscular dystrophy revealed a widespread mantle of abnormal neurogliomesenchymal tissue that covered a dysplastic cerebral cortex. In this area alone, the glia limitans that adjoined the abnormal mantle via one or two layers of basal lamina had frequent breaches, through which neuroglial elements extruded. In the most severely affected cortical region, which had only a rudimentary and fragmentary glia limitans, the majority of cortical neurons had migrated into the neurogliomesenchymal tissue. The massive overmigrated neurons still maintained a somewhat columnar arrangement, and the marked dysplasia abruptly shifted to a neurogliomesenchymal tissue-free normal cortical structure with an intact glia limitans, thus indicating essentially vertical overmigration of neurons without significant tangential migration of them. Together the above findings imply that breaches in the glia limitans may be the primary cause of the micropolygyria seen in this genetic disorder.

[Epidemiology of pertussis and studies on culture positive pertussis cases in Japan]

The number of pertussis patients has decreased steadily in the late 1960s and was extremely small in early 1970s. During 1973-74 the first national survey on pertussis cases confirmed by culture was conducted, when whole cell pertussis vaccine was used. The study revealed that 33.3% of culture positive cases had 2-4 doses of DT combined with whole cell pertussis vaccine. Acellular pertussis vaccine was introduced in 1981 and for the last several years the number of pertussis patients became low for the second time. During 1988-92 exactly the same study was conducted as the previous one. Among 2501 pertussis cases diagnosed clinically 403 were culture positive. Most of the patients were below 1 year of age. Most of the patients were below 1 year of age. Clinical symptoms of those infants were more serious than those of older children. Only 7 out of 403 (1.8%) had a history of 2-4 doses of DT combined with acellular pertussis vaccine. This proved that the acellular pertussis vaccine is by far more effective than the whole cell pertussis vaccine. Serotypes of 377 Bordetella pertussis were identified and 370/377 (98.1%) were serotype 1-3 group.

Characteristics of growth, morphology, contractility, and protein expression of fibroblasts derived from keloid

Phenotypic alterations of keloid-derived fibroblasts were characterized by comparison with the phenotypes of normal fibroblasts from the same patient. Explant cultures of keloids showed unique features. Keloid explants contracted considerably and reduced their size during culture, whereas the size of normal skin explants remained unchanged. Enlarged cells were found among fibroblasts which had grown out of all the explants and were morphologically distinct from fibroblasts; however, keloid explants produced many more of them than did the normal tissues. The growth rate of fibroblast colonies formed from normal explants was five times higher than keloid explants. Keloid fibroblasts which had been serially cultivated contracted lattices of collagen gels at a rate similar to normal fibroblasts. Proteins extracted from serially cultivated fibroblasts were mapped on polyacrylamide two-dimensional electrophoretic gels. No significant qualitative alterations in protein expression in keloid cells were found as compared with normal fibroblasts. However, some quantitative changes were found between the two. A computer-assisted image analyzer detected 151 polypeptide spots--50 spots (33%) of which increased their amounts in keloid cells, whereas 34 spots (22.5%) decreased in comparison with normal fibroblasts. Sixteen major polypeptides were identified as known proteins with the aid of time-of-flight mass spectrometry. The level of expression of these identified proteins was similar between normal and keloid cells, except stathmin whose expression was suppressed in keloid fibroblasts.

Glucose-responsive neurons in the brainstem

AREA POSTREMA: The influence on feeding behavior caused by ablation of the area postrema (AP) in rodents indicates the participation of this structure in the control of ingestion. Two types of glucose responsive neurons were identified in the AP: one is characterized by increasing the discharge rate in response to glucose (glucoreceptor type) and the other by decreasing the discharge rates in response to glucose (glucose sensitive type). These glucose responsive neurons may participate in glycemic homeostasis. NUCLEUS OF SOLITARY TRACT: The glucose responsive neurons exist within the caudal portion of nucleus of the solitary tract (NTS), a relay station in visceral afferents. Two types similar to the AP were also recognized. It is confirmed that hepatic glucose sensitive afferents terminate on some of the glucose sensitive neurons. This convergence may serve as a fail-safe mechanism. In addition, the NTS involving complex neural networks of excitatory and inhibitory interneurons may be concerned with integration of glycemic information. DORSAL MOTOR NUCLEUS OF VAGUS: Some neurons within the dorsal motor nucleus of the vagus (DMV) were identified as the glucose responsive ones. Both types were also recognized. It is confirmed by antidromic activation that these glucose responsive DMV neurons send their axons toward the gastric or coeliac branch that innervates either the stomach, intestine or pancreas. Some of the DMV neurons may subserve an enteroceptor function by themselves. They may also play a role in the brainstem neural control of glycemic homeostasis as the fail-safe mechanism.

Tissue fibronectin is an endogenous ligand for galectin-1

A 14K beta-galactoside-binding lectin (galectin-1) is present in many animal tissues. In a search for endogenous ligands, we surveyed galectin-1-binding proteins in human placenta. Extract of human placenta with 2 M urea was applied to a Sepharose 4B column conjugated with galectin-1 purified from frog (Rana catesbeiana) eggs. Two major proteins eluted with 100 mM lactose from the column-bound fraction showed apparent molecular masses of 220 and 180 kDa on SDS-PAGE under reducing conditions. Western blotting analysis using monoclonal antibodies indicated that these proteins were fibronectin and laminin, respectively. Most placental and amniotic fibronectins bound strongly to the column, whereas almost all plasma fibronectin passed through the column. The galectin-1, fibronectin and laminin were immunohistochemically shown to be co-localized in the extracellular matrix of placental tissue. In a cell attachment assay, rhabdosarcoma cells adhered to a plate coated with placental fibronectin, even in the presence of GRGDS peptide, if galectin-1 were also present. This adhesive effect of galectin-1 was inhibited by lactose. These results indicate that tissue fibronectin, as well as laminin, serve as endogenous ligands for galectin-1, suggesting that galectin-1 may play a role in assembly of the extracellular matrix, or in the control of cell adhesion based on lectin-extracellular matrix interaction.

Comparing the cell population on different intraocular lens materials in one eye

We developed a method to evaluate cell adherence to different intraocular lens (IOL) materials in one eye in which we coated one half of the anterior surface of a poly(methyl methacrylate) (PMMA) IOL with poly(dimethyl siloxane), a silicone material. The lenses were implanted in the anterior chamber of rabbit eyes without lens extraction. Postoperative cellular reaction on the IOL surfaces was studied by specular microscopy. The IOLs were fixed in situ, removed from the eyes, and stained with hematoxylin-eosin so we could evaluate the cell population on the silicone and PMMA surface. Fewer cells were scattered on the silicone surface than on the PMMA surface. This method excludes surgical effects and allows a comparison of various IOL materials in the same eye.

Glucose-responsive neurons exist within the area postrema of the rat: in vitro study on the isolated slice preparation

Responses to glucose of spontaneously active neurons were investigated by extracellular recording in the rat area postrema slice preparations (in vitro). Among 67 spontaneously active neurons, 16 neurons displayed a marked increase or decrease in discharge rate in response to increases or decreases of the glucose concentration in perfusate. These results confirm the existence of glucose-responsive neurons within the area postrema suggested in prior in vivo experiments. Response to CCK or dopamine was also examined on the isolated area postrema slices. The neuron that showed a marked increase in discharge rate responding to glucose elicited a marked increase of discharge rate in response to 2.1 microM CCK, suggesting that glucose and CCK affect the same neurons. Some neurons showed a marked increase or decrease in the discharge rate in response to 20 microM dopamine, but these neurons showed neither response to CCK nor to glucose. It is likely that different neuronal networks in the area postrema contribute to control of ingestion and to initiation of nausea.

[A case of cardiac arrest encephalopathy in athetotic cerebral palsy]

A 25-year-old woman with cerebral palsy of spastic quadriplegia and athetosis showed typical cardiac arrest encephalopathy on neuropathology. The etiology of cerebral palsy was perinatal origin including prematurity, asphyxia and hyperbilirubinemia. Ventricular premature beats had developed since about 20 years of age. Muscle tone also increased with aging and symptoms of vago-vagal reflex were occasionally observed after eating. At 25 years, cardiac arrest occurred and cardiopulmonary resucitation was done immediately. She remained unconscious with absent corneal reflex and irregular respiration. EEG or auditory brain stem response showed flat activity. She died of respiratory failure 53 days after the episode of cardiac arrest. Neuropathology showed bilaterally symmetrical necrosis in the superior colliculi, gracilis nuclei, cuneate nuclei and spinotrigeminal nuclei accompanied with severe necrosis in the cerebrum and cerebellum. These findings in this adult case of total asphyxia were compatible with those observed in total plus partial asphyxia in the neonates. This discrepancy may be due to difference in cerebral maturity. Children or young adults with athetotic type cerebral palsy have a high risk of sudden death. Sudden cardiac arrest seems to play an important role in sudden death of these patients.

Encainide-induced diabetes: analysis of islet cell function

OBJECTIVE

The purpose of this study was to gain insight into the mechanisms responsible for encainide-induced diabetes. Specifically, we sought to determine if absolute insulinopenia was present or whether encainide-induced diabetes was metabolically more like type II than type I diabetes.

RESEARCH DESIGN AND METHODS

Islet function was assessed in a 65 year old white male with encainide-induced diabetes. After 6 months of encainide treatment and 2 months duration of diabetes, C-peptide, glucagon, and glucose levels were measured at baseline and at 30 minute intervals for 120 minutes following an oral mixed meal. These measurements allowed assessment of islet beta and alpha cell function in comparison to control data from our laboratory.

RESULTS

In this patient with encainide-induced diabetes, basal and peak C-peptide concentrations were similar to controls although peak C-peptide occurred substantially later than in controls. At peak glucose, the patient's C-peptide/glucose ratio was low indicating relative (but not absolute) insulinopenia. At baseline, glucagon was relatively depressed. Following Sustacal, there was an increase in glucagon of 100% over baseline compared to a mean glucagon rise in controls of only 8%. There was no serological evidence for autoimmune diabetes as islet cell autoantibodies were absent.

CONCLUSIONS

Similar to other forms of diabetes, encainide-induced diabetes is a bihormonal disorder. The metabolic pattern was more like type II than type I diabetes with C-peptide secretion in the normal range, yet persistent hyperglycemia that suggests relative insulinopenia and concurrent insulin resistance.

Hepatic thermogenesis relation to food intake in the conscious rat

It is well known that the body temperature increases during food intake. However, probably because of high thermal conduction within the body, it is rather difficult to determine the main organ that is the source of participates heat production in association with food intake. Our study revealed that increased temperature in the liver during food intake was more predominant than that in the other parts of the abdomen. To further confirm this, we attempted to measure the temperature of both the liver and blood in the portal vein, simultaneously. The temperature of the liver was always higher than that of the portal blood. This implies that hepatic thermogenesis is continuous. The difference between these two temperatures may indicate whether or not hepatic thermogenesis contributes to the increase in body temperature during food consumption. It becomes apparent that the participation of thermogenesis of the liver, along with that of the brown adipose tissue in body temperature increase, is influenced by the composition of food, such as high or low protein in the diet.

Potentiating effect of morphine upon d-methamphetamine-induced hyperthermia in mice. Effects of naloxone and haloperidol

We have examined changes in rectal temperature of mice after subcutaneous administrations of d-methamphetamine alone or methamphetamine plus morphine. Methamphetamine 5 mg/kg produced slight hyperthermia, while simultaneous administration of morphine (25-100 mg/kg), which alone produces hypothermia, potentiated markedly the increase in body temperature by methamphetamine. Methamphetamine showed a hyperthermic effect in a dose-dependent manner in the presence of morphine. The hyperthermia due to methamphetamine plus morphine was avoided by pretreatment with 10 mg/kg naloxone. When animals were pretreated with 2.5 mg/kg haloperidol, hyperthermia due to methamphetamine alone was completely abolished, while that due to methamphetamine plus morphine was still observed. These results showed that dopamine may be implicated in methamphetamine hyperthermia and a haloperidol-nonsensitive mechanism may be involved in the methamphetamine-morphine hyperthermia.

[Sudden death of alcohol withdrawal syndrome--report of a case]

A 50-year-old driver was arrested in a drunken stupor while he was driving a track. He suddenly died after five days of the arrest in a jail. As time went by, various symptoms of alcohol withdrawal appeared. He was in the state of delirium treatments for about a day before he died. Gross and microscopical examination revealed fibrosis and fatty degeneration of liver and heart lesions representing chronic and acute ischemia. We discussed the cause and the mechanism of the death in the case and reviewed those in the previous observations.

Gastric lesions in rats fed salted food materials commonly eaten by Japanese

A high intake of salted food is thought to be related to the high incidence of stomach cancer in Japan. In the present study, female F344 rats were divided into four groups. They were fed a nutritionally deficient purified diet (Group 1) and standard purified diet (Group 3) for 113 weeks and the same diets supplemented with salted cuttlefish guts, broiled, salted, dried sardines, pickled radish, and soy sauce (Groups 2 and 4). The incidence of papillomas and ulcers of the forestomach was highest in Group 4, which was given the standard diet supplemented with the salty food materials (p less than 0.05). These results suggest the importance of salted food as a suspicious causal factor in human stomach cancer in Japan.

Experimental induction of uterine cancer in rats by N-ethyl-N'-nitro-N-nitrosoguanidine dissolved in polyethylene glycol

In the present experiment we attempted to experimentally induce uterine cancer in rats by injecting into the uterine cavity N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG) dissolved in polyethylene glycol (PEG). Fifty-nine female F-344 rats, 7-8 weeks old, were divided into three groups and each received in the left uterine cavity with laparotomy a single dose of ENNG dissolved in PEG according to the following schedule: Group 1 received 75 mg ENNG/kg body wt.; Group 2 had 20 mg ENNG/kg body wt.: and Group 3 was given only PEG. In Group 1 it was observed that adenocarcinoma and sarcoma were present in the uterine corpus while squamous cell carcinoma occurred in the uterine cervix. In Group 2, although tumors such as adenocarcinoma, adenoma and sarcoma were observed in the uterine corpus, no tumor was present in the uterine cervix. No tumor growth whatsoever was observed in Group 3. From the above results it is apparent that the present method is an efficient means for experimentally inducing uterine cancer and that the site of tumor generation varies according to the concentration of ENNG administered.

Potentiation of lethality and increase in body temperature by combined use of d-methamphetamine and morphine in mice

Lethality and change in body temperature in mice were examined after subcutaneous injection of d-methamphetamine and morphine alone or in combination. The LD50 values for methamphetamine and morphine were calculated to be 95 and 670 mg/kg body wt., respectively. When a non-lethal dose of morphine (300 mg/kg) was administered with various doses of methamphetamine, the LD50 for methamphetamine was reduced to 5 mg/kg, indicating a marked potentiation of toxicity by combined use of both drugs. Injection of 5 mg/kg of methamphetamine produced slight hyperthermia, while 300 mg/kg of morphine decreased the body temperature of mice. However, when both drugs were used concomitantly, a marked increase in body temperature was observed. Hyperthermia was also observed when the dose of morphine was reduced to 50 mg/kg. It is postulated that hyperthermia is probably one of the contributory factors in the potentiated toxicity by combined use of morphine and methamphetamine.

Magnetic resonance imaging in Pelizaeus-Merzbacher disease

Cranial computed tomography of a boy with clinical characteristics of the classic form of Pelizaeus-Merzbacher disease did not reveal a notable abnormality other than enlarged ventricles. Magnetic resonance imaging, however, demonstrated diffuse changes in the white matter with sparing of scattered small areas, suggesting persistent myelin islands which are a typical neuropathologic finding in Pelizaeus-Merzbacher disease. Magnetic resonance imaging appears more useful than computed tomography in confirming the diagnosis of Pelizaeus-Merzbacher disease.

Decrease in d-methamphetamine sensitivity in mice due to ethanol: apparent inhibitory and stimulatory effects of ethanol on d-methamphetamine-induced locomotor activity

The locomotor activity of mice was recorded after administration of d-methamphetamine-HCl (1.5, 2.5, 5.0 and 7.5 mg/kg body weight) and/or ethanol (0.8 and 1.6 g/kg body weight). Mice injected with lower doses of d-methamphetamine (1.5 or 2.5 mg/kg) showed a marked increase in locomotor activity, while in those with higher doses of d-methamphetamine (5.0 or 7.5 mg/kg), locomotor activity was not further enhanced, but slightly decreased. Administration of ethanol inhibited the stimulated locomotor activity caused by low doses of d-methamphetamine (1.5 or 2.5 mg/kg), while the stimulation of motility after higher doses of d-methamphetamine (5.0 or 7.5 mg/kg) was potentiated by administering ethanol. Although apparent inhibition and stimulation of d-methamphetamine-induced locomotor activity of mice due to ethanol was observed, it is suggested that mice administered ethanol showed the decreased sensitivity to d-methamphetamine by plotting total locomotor activity of mice against doses of d-methamphetamine administered. The half maximum effective dose of d-methamphetamine for locomotor activity was increased from 1.5 mg/kg to 3.0 mg/kg by concomitant administration of 1.6 g/kg ethanol.