Differentiation of receptive fields in the sensory cortex following stimulation of various nerves of the lower limb in humans: a magnetoencephalographic study

The authors investigated magnetoencephalography following stimulation of the posterior tibial (PT) and sural (SU) nerves at the ankle, the peroneal nerve (PE) at the knee, and the femoral nerve (FE) overlying the inguinal ligament in seven normal subjects (14 limbs) and confirmed its usefulness in clarifying the detailed differentiation of the receptive fields in the lower limb area of the primary sensory cortex in humans. The results were summarized as follows: 1) the equivalent current dipoles (ECDs) estimated by the magnetic fields following stimulation of the PT and SU were located very close to each other, along the interhemispheric fissure in all 14 limbs. They were directed horizontally to the hemisphere ipsilateral to the stimulated nerve. 2) The ECD following stimulation of the FE was clearly different from that seen in the other nerves, in terms of the location and/or direction, in all 14 limbs. The ECDs of 14 limbs were classified into two types according to the distance of ECD location between PT and FE; Type 1 (> 1 cm, nine limbs) and Type 2 (< 1 cm, five limbs). The ECD following FE stimulation was located on the crown of the postcentral gyrus or at the edge of the interhemispheric fissure in Type 1 and was close to the ECDs following PT and SU stimulation along the interhemispheric fissure in Type 2. 3) The ECD following PE stimulation was located along the interhemispheric fissure in all 14 limbs as for PT and SU. Its location was slightly but significantly higher than that of PT and SU in Type 1 and was close to ECDs following PT and SU stimulation in Type 2. The present findings indicated that approximately 65% (nine of 14) of the limbs showed the particular receptive fields compatible with the homunculus. Large inter- and the intraindividual (left-right) differences found in the present study indicated a significant anatomical variation in the area of the lower limb in the sensory cortex of humans.

[Temporal bone pathology in neonates with severe visceral anomalies]

It is well known that hearing loss is often associated with anomalads, syndromes involving multiple anomalies. The incidence is especially high in severe cases of facial and visceral malformations. However, otologic features remain unclear in patients with a sequence of various anomalies which can not be classified into any known syndrome. We examined 11 temporal bones from 6 patients with severe visceral anomalies, which could not be classified into any known systemic bone diseases, chromosomal abnormalities, or congenital metabolic disorders. Temporal bone pathology was compared with external and visceral anomalies in each case. The temporal bones had been removed at autopsy, fixed in 10% formaldehyde, decalcified and embedded in celloidin. Serial horizontal sections were made at 20 microns and every tenth section was stained with hematoxylin eosin. Most abnormalities in the middle and inner ear were found to have an ectodermal or mesodermal origin. Inner ear abnormalities were noted in 6 temporal bones from 3 patients; the predominant feature was hypoplasia of the semicircular canals. Middle ear abnormalities excluding residual mesenchymal tissue were noted in 5 temporal bones from 4 patients; the predominant feature was an abnormal course of the facial nerve. It was also suspected that auricular and maxillomandibular abnormalities, which are often associated with severe visceral anomalies, indicate a high incidence of disorders affecting the auditory and vestibular systems.

Evoked Magnetic Field Elicited by Motion and Motion Aftereffect

Motion aftereffect (MAE) is a negative aftereffect caused by prolonged viewing of visual motion: after gazing at a moving grating for a while, a stationary image will appear to move in the opposite direction (Ashida and Osaka, 1995 Vision Research35 1825). Evoked magnetic field (magnetoencephalogram: MEG) was measured on a human subject observing visual motion and MAE. Magnetic evoked field (80 averagings) was measured from 37 points over occipital and parietal areas (Magnes SQUID biomagnetometer, BTi) during watching a horizontally moving sinusoidal grating with low spatial frequency (2 cycles deg−1 with 5 Hz: motion condition) and immediately after stopping the moving grating (MAE condition). Dipole estimates based on equal magnetic field contour suggest that the main loci subserving visual motion and MAE appear to be the surrounding region over occipital and parietal areas in the human brain. Further analysis is now underway. In general, this appears to be in good agreement with another study using fMRI-based MAE measures [Tootell et al, 1995 Nature (London)375 139] in which a clear increase in activity in these areas was observed when subjects viewed MAE.

Participation of nitric oxide in the sympathetic response to anaphylactic hypotension in anesthetized dogs

The role of nitric oxide (NO) was determined using a NO synthase inhibitor, NG-nitro-L-arginine methyl ester (L-NAME; 20 mg/kg bolus and 0.05 mg/kg per min) in the renal sympathetic and hypotensive response to systemic anaphylaxis induced by Ascaris suum antigen (10 mg, i.v.) in naturally sensitized anesthetized dogs. Renal nerve activity (RNA) in animals pretreated with D-NAME, the biologically inactive enantiomer (n = 7), showed an initial increase (192 +/- 32%, (mean +/- SE) followed by a decrease (61 +/- 14%) after antigen. Pretreatment with L-NAME (n = 7) did not affect the initial sympathoexcitation but abolished the secondary sympathoinhibition (110 +/- 13%). However, the depressor response to antigen was not different between the L-NAME and D-NAME groups (-87 +/- 13 mmHg and -84 +/- 12 mmHg). In conclusion, NO is involved in the anaphylaxis-induced renal sympathoinhibitory response but not hypotension in anesthetized dogs.

Giant basilar artery aneurysm with intramural hemorrhage and then disastrous hemorrhage: case report

OBJECTIVE AND IMPORTANCE

Intracranial giant aneurysms have been considered to grow by recurrence of intramural hemorrhage of the aneurysmal wall. However, it remains uncertain whether rupture of giant aneurysms is brought about by the same mechanism that causes the rupture of smaller saccular aneurysms. It is also unclear whether intramural hemorrhage is correlated with the rupture of giant aneurysms.

CLINICAL PRESENTATION

A 67-year-old woman was admitted with symptoms of gait disturbance and dementia. Computed tomographic scans revealed a large mass located in the prepontine region and extending into the third ventricle as well as moderate dilatation of the lateral ventricles. Angiography demonstrated a giant basilar tip aneurysm and multiple aneurysms located in the bilateral anterior and middle cerebral arteries.

INTERVENTION

Ventriculoperitoneal shunting was scheduled, but subarachnoid and intraventricular hemorrhage occurred and the patient died. Computed tomographic scans, performed immediately before the disastrous hemorrhage, displayed intramural hemorrhage in the wall of the giant basilar tip aneurysm. Ventricular drainage was performed, but the patient died.

CONCLUSION

It seems probable that intramural hemorrhage of the aneurysmal wall may cause both the growth and rupture of intracranial giant aneurysms.

Spontaneous dissecting aneurysm of the anterior cerebral artery: report of two cases

BACKGROUND

Dissecting aneurysms of the vertebrobasilar artery have been increasingly reported. However, those of the anterior circulation are still rare lesions. Those confined to the anterior cerebral artery are extremely rare and their clinical features are not well known.

CASE REPORT

Two cases of spontaneous dissecting aneurysm of the anterior cerebral artery are described. Both patients are middle-aged males and presented with ischemic attacks, although they were lacking any factors correlated to atherosclerosis. Definite diagnosis was made by angiography, which demonstrated characteristics of dissecting aneurysm, such as "double lumen" and "string sign." Serial angiography was performed and revealed dynamic changes during the time course. Nonsurgical therapy was utilized and both patients achieved good recovery.

CONCLUSION

Most of the dissecting aneurysms confined to the anterior cerebral artery present with ischemic attacks. Although their etiology remains uncertain, such aneurysms may be a potent cause of occlusive diseases of the anterior cerebral artery, especially in relatively young males lacking any factors correlated to atherosclerosis.

A naturally occurring 46-amino acid deletion of cytidine monophospho-N-acetylneuraminic acid hydroxylase leads to a change in the intracellular distribution of the protein

Cytidine monophospho-N-acetylneuraminic acid (CMP-NeuAc) hydroxylase is a key enzyme for the expression of N-glycolylneuraminic acid. The molecular cloning of this enzyme from mouse liver has been described in our previous report (Kawano T, Koyama S, Takematsu H, Kozutsumi Y, Kawasaki H, Kawashima S, Kawasaki T, Suzuki A (1995) J Biol Chem 270: 16458-63). During the cDNA cloning, a cDNA containing a truncated open reading frame (ORF) was isolated. This clone encodes a protein of 531 amino acids which lacks 46 amino acids in the middle of the normal full-length protein. The percentage of this mRNA containing the truncated ORF out of the total population of CMP-NeuAc hydroxylase mRNA in various mouse tissues was about 10-25%. The truncated protein was expressed in COS-1 cells, but did not show any enzymatic activity. The truncated protein was localized to the region which appeared to be the endoplasmic reticulum, whereas the full-length protein with normal enzymatic activity was detected in the cytosol. These data suggest that this naturally occurring 46-amino acid deletion leads to a change in the intracellular distribution of CMP-NeuAc hydroxylase, and a loss in the activity of this enzyme.

[Hypertonic saline induced bronchoconstriction in sensitized rabbits]

Hypertonic saline is a potent stimulus to airway narrowing in most asthmatic patients. However, the mechanism of airway narrowing induced by a change in osmolarity is not clearly understood. In ovalbumin-sensitized rabbits, we found that bronchoconstriction occurred after inhalation of hypertonic saline, and then studied the mechanisms responsible for this bronchoconstriction. Eighteen anesthetized, paralyzed, mechanically ventilated (40 breath/min, TV 7 ml/kg) ovalbumin-sensitized rabbits were exposed to aerosols of hypertonic saline (ultrasonic nebulizer, 0.5 ml/min, 1 min). Total lung resistance (RL) and dynamic compliance (Cdyr) of the lung were measured before and after the exposure. The concentration of NaCl was increased from 0.9% to 7.2% in 0.9% steps. RL increased and Cdyr decreased as the dose of NaCl rose and they reached plateaus at doses of 6.3% and 7.2%, respectively. These responses were markedly inhibited by treatment with atropine (5 mg/kg i.v., p < 0.05 vs. control group), but treatment with chlorpheniramine (1 mg/kg iv.) suppressed the responses only at low concentrations of NaCl. In contrast, treatment with indomethacin, did not significantly change the responses. We conclude that inhalation of hypertonic saline can cause bronchoconstriction in sensitized rabbits, and that vagal stimulation plays a major role in this bronchoconstriction.

Primary diaphragmatic schwannoma with a typical target appearance: correlation of CT and MR imagings and histologic findings

A rare case of benign diaphragmatic schwannoma in a 38-year-old female is reported. Precontrast computed tomography (CT) showed an encapsulated well-defined round homogeneous tumor with central calcification, measuring approximately 5 cm in diameter, arising from the left diaphragm. Contrast-enhanced CT and gadolinium-enhanced T1-weighted magnetic resonance (MR) imaging showed focal enhancement in the central portion of the tumor. The tumor showed a typical target appearance of increased peripheral signal intensity and decreased central signal intensity on unenhanced T2-weighted images. Pathological examination of resected specimens of the tumor showed two zonal histological components: a hypercellular portion of spindle cells with nuclear palisading (Antoni A tissue) and a hypocellular portion of cells with cystic degeneration, together with focal calcification and hemangeomatous vascular changes (Antoni B tissue). We consider the radiological characteristics of diaphragmatic schwannoma on CT and MR imagings to represent the geographic difference between the histologic zones of the tumor.

Effects of judgement process on motor evoked potentials in Go/No-go hand movement task

We examined the motor evoked potentials (MEP) of the forearm muscles following transcranial magnetic stimulation after the Go/No-go reaction-time hands movement in ten normal subjects. Facilitation of MEP of the agonistic muscles and suppression of MEP of the antagonistic muscles were recognized during the 'Go' session, while the MEPs of both muscles were markedly suppressed in the 'No-go' session. We considered that this MEP changes reflected the inhibition on the pyramidal tract during the 'No-go' session.

Somatosensory evoked magnetic fields following stimulation of the lip in humans

The topography of somatosensory evoked magnetic fields (SEFs) following stimulation of the upper and lower lips was investigated in 6 normal subjects. When the lateral side of the upper lip was stimulated, P20m and its counterpart, N20m, were identified in the hemisphere contralateral to the stimulated side. The equivalent current dipoles (ECDs) of N20m-P20m were considered to be located in lip area of the primary sensory cortex (SI). Middle latency deflections (N40m-P40m, N60m-P60m, and N80m-P80m) were identified in bilateral hemispheres. Their ECDs were located in the SI in both hemispheres. Long latency deflections (P110m-N110m) were recognized in both hemispheres, and their ECDs were located inferior to the SI, in an area considered to be the secondary sensory cortex (SII). When the midline of the lip was stimulated, similar short and middle latency deflections was also identified, but SII deflections (P110m-N110m) were decreased in amplitude. When the lower lip was stimulated, the ECDs of short and middle latency deflections were located at a site in the SI inferior to or near those elicited by upper lip stimulation. The ECDs of P110m-N110m were located in an area of the SII similar to that upon stimulation of the upper lip, but their orientations were different.

Ras-interacting domain of RGL blocks Ras-dependent signal transduction in Xenopus oocytes

RalGDS family members (ralGDS and RGL) interact with the GTP-bound form of Ras through its effector loop. The C-terminal region (amino acids 602-768) of RGL is responsible for binding to Ras. In this paper we characterized a Ras-interacting domain of RGL using deletion mutants of RGL(602-768). RGL(602-768), RGL(632-768), and RGL (602-734) bound to the GTP-bound form of Ras and inhibited the GAP activity of NF-1. RGL(646-768) showed a low binding activity to Ras and inhibited GAP activity of NF-1 weakly. None of RGL(659-768), RGL(685-768), RGL(602-709), and RGL(602-686) bound to Ras or inhibited GAP activity of NF-1. These results indicate that amino acids 632-734 of RGL constitute a nearly minimal domain that contains the binding element for Ras. RGL(632-734) inhibited v-Ras- but not progesterone-induced Xenopus oocyte maturation. Furthermore, RGL(632-734) inhibited v-Ras- but not v-Raf- dependent extracellular signal-regulated kinase activation in Xenopus oocytes. These results clearly demonstrate that the Ras-interacting domain of RGL is important for Ras-dependent signal transduction in vivo.

The effects of sevoflurane, enflurane, and isoflurane on baroreceptor-sympathetic reflex in rabbits

This study was designed to determine the effects of sevoflurane, enflurane, and isoflurane ranging from 0.5 to 1.25 minimum alveolar anesthetic concentration (MAC) on spontaneous efferent renal sympathetic nerve activity (RNA) and the barorecptor-sympathetic reflex in rabbits. Enflurane produced significant decreases in spontaneous RNA by 22.5% +/- 6.6% at 1.0 MAC, while sevoflurane and isoflurane, at the equivalent MAC, did not. All of the anesthetics attenuated the baroreflex gain similarly when mean blood pressure (MBP) was changed by sodium nitroprusside or phenylephrine intravenously. However, the sensitivity of baroreceptors at the aortic wall was not changed by any anesthetic, because no changes in the relationship between aortic nerve activity and MBP were obtained in anesthetic concentration even at 1.25 MAC. Furthermore, these anesthetics suppressed the sympathoinhibitory response to aortic nerve stimulation above 1.0 MAC. In conclusion, enflurane inhibits RNA to a greater degree than sevoflurane or isoflurane. However, all three anesthetics depress the reflex regulation of RNA to the same degree. The suppression on the baroreceptor-sympathetic reflex does not appear to be related to a change in the receptor sensitivity on the aorta, but is mediated by suppression of the central or peripheral sympathetic integrating system.

Reciprocal change of motor evoked potentials preceding voluntary movement in humans

Reciprocal change of motor evoked potentials (MEPs) recorded from the agonist and antagonist muscles of the forearm was studied in 10 normal subjects in whom transcranial magnetic stimulation (TMS) was applied to the hand motor area before voluntary wrist movements. MEP recorded from the agonist muscles, that is, radial extensor muscles for wrist extension and ulnar flexor muscle for wrist flexion, were gradually facilitated with shortening of the interval between the magnetic stimulation and the voluntary muscle contraction. In contrast, MEP recorded from the antagonist muscles, that is, ulnar flexor muscle for wrist extension and radial extensor muscles for wrist flexion, were gradually suppressed as the interval shortened. The reciprocal change of MEP was recognized when TMS was applied within 60 ms prior to the voluntary movements. The present data confirmed that reciprocal change of MEP was recognized before voluntary movements; they further suggest that cortically originated reciprocal control of the corticospinal pathway may exist and that it may be generated just before the voluntary movement.

Acute respiratory distress syndrome due to methicillin-resistant Staphylococcus aureus sepsis in hyper-IgE syndrome

We report the case of a 34 year old woman with acute respiratory distress syndrome (ARDS) and disseminated intravascular coagulation (DIC) due to methicillin-resistant Staphylococcus aureus (MRSA) sepsis with hyperimmunoglobulin E syndrome (HIES). Although chemotactic activity of neutrophils was impaired in this patient, neutrophils accumulated in the lungs as assessed by bronchoalveolar lavage fluid (BALF) counts. In addition to antibiotics and oxygen therapy, the administration of recombinant human granulocyte colony-stimulating factor (rhG-CSF) resulted in a remarkable recovery.

Effects of tactile interference stimulation on somatosensory evoked magnetic fields

Tactile stimulation of the hand interferes with somatosensory evoked brain responses following electrical median nerve stimulation. This effect was studied in eight normal subjects by magnetonecephalography (MEG). When stimulation was applied to the hand ipsilateral to the stimulated nerve, only the third response (3M) was enhanced in five subjects, but other responses were attenuated in all subjects. These interference effects were probably due to interactions in areas 3b and 1. After stimulation of the contralateral hand, only the second response (2M) was enhanced in six subjects. This effect was probably due to the intracerebral interactions mediated through the corpus callosum.

[Immunoglobulin positive cells in paranasal mucosa treated with macrolides]

The present study was carried out to determine the correlation between the efficacy of macrolide therapy and clinical features of chronic sinusitis. We performed an immunohistological study of subepithelial inflammatory cells in the paranasal mucosa from the patients of chronic sinusitis treated with low-dose, long-term administration of macrolides, and obtained the following results. 1) Many IgA and IgE positive cells were observed in subepithelial area, while IgG and IgM positive cells were sparse. 2) The cases with many IgA positive cells in subepithelial layer before the therapy showed good response to macrolides, and a number of IgA positive cells decreased after the therapy. 3) The number of IgE and IgM positive cells showed little change after the therapy. IgG positive cells tended to increase in number after the therapy. 4) The ratio of number of IgA positive cells and IgE positive cells (IgA/E) significantly decreased after the therapy, especially in responders to the therapy. 5) The value of IgA/E was significantly low in eosinophil-dominant cases. These results suggested that macrolides suppress chronic inflammatory response except for eosinophil and IgE-dominant inflammation.

Antiproteases attenuate the release of neutrophil chemotactic activity from bronchial epithelial cells induced by smoke

The released neutrophil chemotactic activity (NCA) from bronchial epithelial cells (BECs) in response to smoke extract was evaluated by reverse-phase, high-performance liquid chromatography (RP-HPLC) and the involvement of proteolytic activity was assessed for the release of NCA from BECs. Smoke extract stimulated the release of NCA (55.3 +/- 5.2 vs. 17.3 +/- 4.1 cells per high-power field [HPF], p < .001). The released activity determined by RP-HPLC analysis was 15-hydroxyeicosatetraenoic acid and leukotriene B4. Several structurally and functionally different serine protease inhibitors, including alpha-1-protease inhibitor (alpha-1-PI), chloromethyl ketone (CK) derivatives, N-tosyl-L-lysine CK (TLCK), methoxysuccinyl-Ala-Ala-Pro-Val CK (SPCK), N-alpha-tosyl-L-phenylalanine CK (TPCK), and N-alpha-p-tosyl-L-arginine methyl ester hydrochloride (TAME), attenuated the release of NCA (P < .01) in a dose-dependent fashion. Leupeptin, a cysteine protease inhibitor, has only a small effect on the release of NCA (p < .05), and phosphoramidon, a neutral endopeptidase inhibitor, had no effect. The measurement of proteolytic enzyme activity using synthetic substrate S-2288 revealed that smoke extract significantly (p < .05) augmented the serine protease activity in BEC layers. Culture supernatant fluids and cell lysates of BECs in response to smoke extract solubilized 14C-labeled casein. These results suggest that BECs may release lipoxygenase-derived NCA in response to smoke extract and that the release of NCA may involve the activation of proteolytic activity of BECs which was inhibited by serine protease inhibitors.

Effects of noxious cooling of the skin on pain perception in man

By means of somatosensory evoked brain potentials following painful CO2 laser stimulation (pain SEPs) and a pain visual analogue scale (VAS), we investigated changes in pain perception caused by noxious cooling of the skin in normal subjects. Pain SEPs were recorded from scalp electrodes following laser stimulation applied to the leg under various conditions as follows: (1) control (without any interference); (2) 46 degrees C foot (dipping the foot ipsilateral to the stimulated leg in hot water at 46 degrees C); (3) 0 degrees C foot (dipping the foot ipsilateral to the stimulated leg in ice water at 0 degrees C); and (4) 0 degrees C hand (dipping the hand contralateral to the stimulated leg in ice water at 0 degrees C). Marked decreases in amplitude of pain SEPs and VAS were observed under all conditions as compared with the control (P < 0.001); the degree of pain relief was significantly correlated with changes in pain SEPs. These changes were greatest in the '0 degrees C hand' condition, followed in decreasing order by '0 degrees C foot' and '46 degrees C foot', and there was a significant difference between '0 degrees C hand' and the '46 degrees C foot' condition. We considered that the decrease in pain is due to the diffuse noxious inhibitory control (DNIC). The reason why the degree of pain relief in '0 degrees C foot' condition was less than that in '0 degrees C hand' condition is unclear, but some particular spatial summation of two kinds of nociceptive impulses mediated by the same pathway might take place.

Systemic lupus erythematosus with pulmonary hypertension

A 50-year-old Japanese female with a long history of Raynaud's phenomenon presented with progressive dyspnea due to pulmonary hypertension. The diagnosis of systemic lupus erythematosus was confirmed by proteinuria, lymphocytopenia, bilateral pleurisy, and a seizure of convulsion which was consistent with neurological manifestations of systemic lupus erythematosus, whereas the antinuclear antibody showed a low titer. Despite improvement in the activity of systemic lupus erythematosus, steroid treatment did not alter the progression of pulmonary hypertension, which increased in severity, eventually resulting in her death. We believe pulmonary hypertension to be an unusual but critical complication of systemic lupus erythematosus.

Intracerebral interactions caused by bilateral median nerve stimulation in man: a magnetoencephalographic study

Somatosensory evoked magnetic fields (SEFs) following stimulation of the median nerves bilaterally ('bilateral' waveform) were examined in normal subjects to determine the interference effects of activation of sensory areas in bilateral hemispheres. SEFs following right median nerve stimulation and those following left median nerve stimulation were summated ('summated' waveform). A 'difference' waveform was induced by subtraction of the 'bilateral' waveform from 'summated' waveform. Short-latency deflections showed no consistent differences between the 'summated' and 'bilateral' waveforms, but the middle-latency deflection. N60m-P60m, in the 'bilateral' waveform was significantly (P < 0.01) smaller than that in the 'summated' waveform. The long-latency deflection, the N90m-P90m, in the 'bilateral' waveform was markedly (P < 0.001) reduced in amplitude as compared with the 'summated' waveform. The differences were clearly identified in the 'difference' waveform, in which the main deflections, U90m-D90m, were found in all subjects. Equivalent current dipoles (ECDs) of the short- and middle-latency deflections were located in the primary sensory cortex (SI) contralateral to the stimulated nerve, but ECDs of the N90m-P90m and U90m-D90m were located in bilateral second sensory cortices (SII) which are considered to receive ascending signals from bilateral sides of the body.

A scintillating fiber beam-energy monitor for electron beam therapy

A new type of beam-energy monitor is described, which has been developed to check the energies of electron beams from radiotherapy accelerators. The monitor consists of a pair of scintillating fibers and photodiode read-out circuits that measure the energy dependence of electron transmission through a wedge-shaped absorber. A linear energy response and 1% accuracy for energy constancy measurements are attained with the monitor. The monitor having advantages of simple mechanical and electronic constructions, small size, and low cost is suitable for practical use as a portable device.