[A case of juvenile type dentatorubral-pallidoluysian atrophy (DRPLA) with psychomotor retardation since infancy]

We report here a case of an 11-year-old boy with juvenile type of dentatorubral-pallidoluysian atrophy (DRPLA). His psychomotor development has been delayed since infancy and cerebellar ataxia was noted at the age of 2 years, indicating an early onset. At the age of 6 years, he had progressive myoclonus epilepsy (PME) and underwent a series of neuroradiological, electrophysiological and pathological examinations, which failed to reveal the etiology. Gene analysis performed at the age of 11 years revealed an expanded CAG repeat at the DRPLA locus in both the patient and his asymptomatic father. In the absence of a positive family history, a diagnosis of DRPLA may be difficult due to its clinical variability. We conclude that DRPLA should be taken into account in the differential diagnosis of childhood PME and that gene analysis should be performed to confirm a diagnosis of DRPLA.

Gender difference in age-related changes in muscle sympathetic nerve activity in healthy subjects

Muscle sympathetic nerve activity (MSNA) was measured directly along with blood pressure at rest in 69 healthy women (20-79 yr old) and 76 age-matched healthy men (16-80 yr old). All were nonobese and normotensive. In the women and men the MSNA was positively correlated with age (women: y = 0.788x - 5.418, r = 0.846, P < 0. 0001; men: y = 0.452x + 12.565, r = 0.751, P < 0.0001). The regression intercept of y was significantly lower (P < 0.0001) in the women than in the men, and the regression slope was significantly steeper (P < 0.0001) in the women. The MSNA was lower in women than in men among those <30 (P = 0.0012), 30-39 (P = 0. 0126), and 40-49 yr old (P = 0.0462) but was similar in women and men among those 50-59 (P = 0.1911, NS) and >/=60 yr old (P = 0.1739, NS). The results suggest that MSNA increases with age in women and men and that the activity is markedly lower in young women than in men but is markedly accelerated with age.

Effects of lower body positive pressure on muscle sympathetic nerve activity

To elucidate the role of vasomotor sympathetic nerve activity response to lower-body positive pressure (LBPP), muscle sympathetic nerve activity (MSNA) along with blood pressure, electrocardiogram, transthoracic impedance and echocardiogram were recorded in ten healthy young men at 10, 20 and 30 mmHg LBPP in the supine position. We found that MSNA was suppressed (27%) at both 10 and 20 mmHg LBPP but tended to increase at 30 mmHg LBPP. Mean arterial pressure (11%) and total peripheral resistance (36%) increased despite a tendency toward decreased stroke volume and cardiac output at 30 mmHg LBPP. Heart rate remained unchanged. The left atrial dimension significantly increased during 10-30 mmHg LBPP, indicating an increase in cardiac filling. These results suggest that LBPP at levels less than 20 mmHg suppressed MSNA by the translocation of blood from the lower body to the thorax, thus stimulating the cardiopulmonary baroreceptors which in turn inhibited vasomotor sympathetic nerve activity. However, LBPP at 30 mmHg tended to enhance MSNA through the activation of intramuscular (pressure-sensitive) receptors which could counteract the inhibitory effect of cardiopulmonary baroreflexes on MSNA.

Responses of muscle sympathetic nerve activity to lower body positive pressure

To evaluate the response of vasomotor sympathetic nerve activity to lower body positive pressure (LBPP), muscle sympathetic nerve activity (MSNA) was microneurographically recorded from the tibial nerve in 10 healthy young men, along with hemodynamic variables and echocardiogram, during exposure to incremental LBPP at 10, 20, and 30 mmHg in the supine position. MSNA was suppressed to a similar extent (27%) at 10- and 20-mmHg LBPP. However, at 30-mmHg LBPP, MSNA tended to increase but was still nearly at the control value. Mean arterial pressure was elevated (11%), total peripheral resistance markedly increased (36%), and stroke volume and cardiac output tended to decrease at 30-mmHg LBPP. Heart rate remained unchanged throughout the procedures. Left atrial dimension significantly increased during 10- and 30-mmHg LBPP, indicating an increased cardiac filling. These results suggest that the inhibitory effect of the cardiopulmonary baroreflex on MSNA at 10- and 20-mmHg LBPP could be counteracted by the sympathoexcitatory effect of the intramuscular pressure-sensitive mechanoreflex at 30-mmHg LBPP. However, the increment of total peripheral resistance at 30-mmHg LBPP may not depend exclusively on this small enhancement of MSNA.

Sympathetic nerve response to muscle during anteroposterior acceleration in humans

This study aimed to elucidate the effects of linear acceleration on muscle sympathetic nerve activity (MSNA) in humans. Eight healthy young male volunteers were seated in a linear accelerator (sled) during the recording of their electrocardiogram, blood pressure with the Finapres, thoracic impedance and respiration curve. MSNA was recorded from the tibial nerve by microneurography. At a fixed distance of sled movements in an anteroposterior direction, eight modes of stimulation with peak accelerations at 0.05, 0.10, 0.15, and 0.20 G (gravity) in sinusoidal or step mode were applied to each subject. Each movement was repeated for 5 cycles. Both the total activity and the burst rate of MSNA decreased during acceleration, and the level of the decrease was proportional to the level of the acceleration, whereas the average heart rate, thoracic impedance and mean arterial pressure did not change significantly. These results suggests that moderate linear acceleration may suppress MSNA in humans.

Intracranial lipoma of the quadrigeminal region associated with complex partial seizures

A 7-year-old Japanese boy with an intracranial lipoma of the quadrigeminal region and complex partial seizures is reported. Among 28 published patients with lipoma originating in the quadrigeminal plate and ambient cistern, 6 suffered from seizures and 3 were mentally retarded. Our patient's seizures were controlled with carbamazepine.

Characteristic MR features of encephalitis caused by Epstein-Barr virus: a case report

An 8-year-old girl showed symptoms of encephalitis during acute Epstein-Barr virus (EBV) infection. The diagnosis of EB virus infection was made by changes in the titres of EB virus-specific antibody. Cranial MRI demonstrated abnormal low and high signal intensities in the striatal body (putamen and caudate nucleus) on T1-weighted and T2-weighted images, respectively, during the acute phase. These abnormal findings had almost completely resolved 1 month later. EBV infection should be considered when lesions are localised to the basal ganglia.

Sympathetic nerve responses in humans to short and long term simulation of microgravity

The present paper aimed to review findings obtained by our researches to elucidate sympathetic nerve mechanisms of cardiovascular deconditioning in humans exposed to short and long term simulation of microgravity. Sympathetic nerve activity in humans has been so far investigated using indirect methods by analyzing the activities of effector organs, such as heart rate, blood flow, blood pressure, sweating etc. or by measuring the plasma nor-adrenaline level. Now we have a technique called microneurography which has enabled us to measure directly the sympathetic nerve activity form human peripheral nerves. The microneurography technique was used for the first time before, during and after the Space Shuttle "Neurolab" mission launched in April 1998 to elucidate how sympathetic nerve activity in astronauts is modified by exposure to microgravity in space. In this paper, we would like to present our recent findings concerning sympathetic nerve responses to short and long term microgravity simulated by different methods.

Head-up suspension in humans: effects on sympathetic vasomotor activity and cardiovascular responses

We hypothesized that muscle sympathetic nerve activity (MSNA) and cardiovascular responses to the conventional head-up tilt (HUT) are different from those to head-up suspension (HUS) because of antigravity muscle activity. The MSNA from the tibial nerve, heart rate, blood pressure, stroke volume, cardiac output, and calf blood flow were measured in 13 healthy young subjects. Left atrial diameter was measured by two-dimensional echocardiography in another nine subjects. The resting MSNA and cardiovascular responses at a low level (20 degrees) of orthostasis were similar during both modes. At higher levels (40 and 60 degrees), the responses of MSNA, heart rate, stroke volume, and cardiac output were significantly stronger and there was a smaller reduction in calf blood flow during HUT than during HUS (P < 0.05). Left atrial diameter was decreased significantly from the resting values during HUT and HUS without any significant difference between the modes of orthostasis. The results provide evidence that the engagement of antigravity muscles during HUT may have additive effects on sympathetic vasoconstrictor and cardiovascular responses to orthostatic stress.

Vitamin E and coenzyme Q concentrations in the thyroid tissues of patients with various thyroid disorders

To clarify the different roles of free radical scavenging systems in various thyroid disorders, we measured the levels of alpha-, beta-, and gamma-tocopherols and coenzyme Q in the thyroid tissues of patients with thyroid tumors and Graves' disease using high-performance liquid chromatography. The levels of alpha-tocopherols and gamma-tocopherols in the thyroid tissue of patients with papillary carcinoma and the level of gamma-tocopherol in the thyroid tissue of patients with malignant lymphoma were elevated compared with those in normal thyroid tissues. The level of coenzyme Q was reduced in the thyroid tissue of patients with Graves' disease and follicular and papillary thyroid carcinomas. These findings imply that vitamin E and coenzyme Q as scavengers play some role in thyroid follicular cell hyperfunction or dysfunction.

Isolated lissencephaly sequence with balanced chromosome translocation involving 17p13.3

We describe a patient with isolated lissencephaly sequence (ILS) who had a de novo balanced translocation with breakpoint at 8p11.23 and 17p13.3. She developed infantile spasms and had severe developmental delay. There was no apparent deletion of 17p13.3 on fluorescence in situ hybridization (FISH) analysis. The breakpoint was located centromeric to the Miller-Dieker syndrome (MDS) marker (D17S379), and telomeric to the marker D17S1566, which is located centromeric to the LIS1 gene. This is the second reported case of ILS with balanced translocation. It is suspected that the breakpoint of 17p13.3 in this patient is located in the responsible gene for ILS.

Effects of thyroid hormone on catecholamine and its metabolite concentrations in rat cardiac muscle and cerebral cortex

Clinical and experimental data suggest that thyroid hormone affects the actions of catecholamine (CA). However, the serum or tissue levels of CA during thyroid disorders have not been well defined. Accordingly, we investigated the levels of CA and their metabolites in the cardiac muscle, the cerebral cortex, and the plasma of rats with hyperthyroidism and hypothyroidism versus euthyroid animals. The Neurochem analyzer system (ESA, Inc., Bedford, MA) was used in such determinations. The cardiac muscles of hyperthyroid rats exhibited a 16% decrease in the levels of 1-dopa, 3-methoxytyramine (3-MT) and homovanillic acid (HVA) as compared with those in euthyroid rats. The levels of norepinephrine (NE) in cardiac muscle of these rats increased significantly (5.2-fold) relative to the levels in euthyroid rats. NE was undetectable in the cardiac muscles of the hypothyroid rats. Epinephrine (E) and dopamine (DA) were not detected in the cardiac muscles of the rats with either thyroid disorder. Levels of E and 3,4-dihydroxymandelic acid (DOPEG) were detected only in the cerebral cortex of hyperthyroid rats. The cerebral cortex levels of 3-methyoxytyramine (3-MT), 3,4-dihydroxyphenylacetic acid (DOPAC), metanephrine (MN), and homovanillic acid (HVA) were all significantly increased in the hyperthyroid versus the euthyroid rats. The cerebral cortex levels of DA, NE, normetanephrine (NMN), and VMA in the hyperthyroid rats all showed a significant decrease. Levels of NE, NMN, and DOPAC in the cerebral cortex increased significantly in the hypothyroid rats. The level of VMA was undetectable in cerebral cortex of such animals. Data from studies on cardiac muscle and cerebral cortex indicate that the changes in CA and CA metabolites are responsible in part for the cardiovascular and the central nervous system symptoms observed in hyperthyroidism and hypothyroidism.

Microneurographic research on sympathetic nerve responses to environmental stimuli in humans

The sympathetic nervous system plays an important role to maintain the homeostasis of vital functions in humans against environmental stimuli. Sympathetic nerve responses to environmental stimuli in humans have been assessed conventionally using rather indirect methods by analyzing the responses of effector organs or by measuring the changes in plasma norepinephrine level. Meanwhile, the microneurography technique has enabled us to approach the sympathetic nervous system in humans more directly. By applying this technique, it has become possible to investigate how the human sympathetic nervous system responds to different kinds of environmental stimuli. In this paper, the usefulness of microneurography as a research tool in environmental physiology is shown together with a review of microneurographic findings on sympathetic nerve responses to environmental stimuli in humans.

Vasodilator component in sympathetic nerve activity destined for the skin of the dorsal foot of mildly heated humans

1. Skin sympathetic nerve activity (SSNA) was recorded in seven male subjects from the peroneal nerve by microneurography, and the temporal correspondence of spontaneously occurring SSNA bursts with vasodilatation and sweating responses on the dorsal foot was studied during a mild body heating at rest. 2. Some SSNA bursts were followed by a sweat expulsion with a latency of 2.4 +/- 0.4 s, and some bursts by a transient vasodilatation with a latency of 2.2 +/- 0.4 s (means +/- S.D.). SSNA bursts followed both by a sweat expulsion and by a vasodilatation response (Type 1), those followed only by a sweat expulsion (Type 2) and those followed only by a vasodilatation, response (Type 3) were 70%, 10% and 1% of the total bursts examined, respectively. 3. For Type 1 bursts, there was a significant, but weak linear relationship among the burst amplitude, the amplitude of the corresponding vasodilatation and the amplitude of the corresponding sweat expulsion. 4. It was concluded that SSNA contains vasodilatory activity which is synchronous with sudomotor nerve activity. The results suggest that such vasodilatory activity contributes to sustaining the sweat gland function by supplying sufficient blood.

Effects of three days of dry immersion on heart rate and blood pressure variabilities during head-up tilting in humans

In this study we examined the effects of 3 days of dry immersion on heart rate variability (HRV) and blood pressure variability (BPV) in response to head-up tilting in 4 healthy young subjects aged 21 to 36 years. Resting value of the high-frequency (HF) power of BPV and HRV decreased, while the low-frequency (LF)/HF ratio of HRV and blood pressure increased after the dry immersion. The HF power of HRV decreased, while the LF/HF ratio of HRV and heart rate increased during head-up tilting before and after dry immersion. All powers of BPV and BP were unchanged during head-up tilting. The values of the decrease in the HF power of HRV and the increase in the LF/HF ratio during head-up tilting after dry immersion were larger than those before. These results suggest that 3 days of dry immersion altered the autonomic balance toward the sympathetic dominant at rest, and that cardiac function may play a crucial role in BP maintenance during head-up tilting compared with vasoconstrictor function.

Sympatho-vagal responses in humans to thermoneutral head-out water immersion

To clarify the role of autonomic nervous functions in cardiovascular adaptation to microgravity, heart rate variability (HRV) and blood pressure variability (BPV) were evaluated during thermoneutral head-out water immersion (HOI) of eight healthy young subjects 23 to 31 yr of age. The very low-frequency (VLF; 0.00-0.04 Hz) component of BPV tended to increase during HOI, whereas the low-frequency (LF; 0.04-0.15 Hz) component of BPV and the ratio of LF power to high-frequency (HF; 0.15-0.40 Hz) component (LF/HF ratio) of HRV decreased. The HF component of HRV increased in all the subjects during immersion up to the shoulder. Concomitantly, we found a decrease in heart rate and increases in stroke volume and cardiac output with no significant changes in BP and respiration rate during HOI. These results suggest that both vasomotor and cardiac sympathetic activities are suppressed and that the parasympathetic (vagal) activity is enhanced during HOI.

Sympathetic nerve response to microgravity induced by parabolic flight

The aim of this study was to clarify how muscle sympathetic nerve activity (MSNA) in humans, which plays an important role in blood pressure control against gravity, is altered under microgravity conditions. Subjects were seated in a jet aircraft with their legs extended. MSNA was recorded microneurographically from the tibial nerve of the sitting subjects with simultaneous monitoring of electrocardiogram, blood pressure, respiration, and intrathoracic blood volume during parabolic flights. In the Air Force training area, the aircraft made parabolas up to 10 times. At the entry to microgravity, intrathoracic blood volume increased, systemic blood pressure was elevated, and MSNA was suppressed. However, this MSNA suppression lasted only 10-15 sec, and then followed by an enhancement to the end of the parabolas. We conclude that MSNA is suppressed at the onset of microgravity during parabolic flight in response to loading of the cardiopulmonary volume receptor due to a cephalad body fluid shift. However, this MSNA suppression is transient during such dynamic gravitational changes as those induced by parabolic flight, probably modulated by arterial baroreceptors.

A comparison of sympathetic vasomotor and cardiovascular responses to head-up tilt and to head-up suspension in humans

Muscle sympathetic nerve activity (MSNA) from the tibial nerve, heart rate (HR), respiration and blood pressure (BP) changes were recorded in 7 healthy young adults to investigate the role of antigravity muscle activity on the reflex sympathetic vasomotor and circulatory responses during orthostatic stress. The conventional passive graded head-up tilt (HUT) with a foot-board and the graded head-up suspension (HUS) with a body harness that provide orthostasis without weight bearing by the legs were applied for 3 consecutive, sequential 5-min periods at the levels of 20, 40 and 60 degrees. The resting values and responses to the lower level (20 degrees) of orthostasis by both techniques were similar. However, the changes in MSNA and HR during the HUS at higher levels (40 and 60 degrees) were smaller with a slight increase in mean BP at 60 degrees than the HUT at the same levels and duration (p<0.05). Antigravity muscle activity during the HUT generates tension in the muscles and may activate muscle mechanoreceptors. Therefore, the reflex sympathetic vasomotor activity and circulatory responses to the HUT in humans are probably due to the additive effects of both the baroreflexes and muscle mechanoreflexes.

Sympathetic control of hemodynamics during moderate head-up tilt in human subjects

To confirm sympathetic control of hemodynamics during postural change, sympathetic nerve activity supplying the anterior tibial muscle (MSNA) was measured by microneurography and muscle blood flow (MBF) by the xenon washout method during graded head-up tilt from 0 degrees horizontal to 30 degrees in 5 degrees increments. MSNA was represented as the increase in burst rate with increased tilt angle. The increments of MSNA from 0 degree horizontal were statistically significant at all tilt angles. MBF decreased gradually with increasing tilt angle, with no difference noted from 5 to 15 degrees, but a significant decrease between 20 and 30 degrees. Mean blood pressure remained unchanged during graded tilt. The heart rate did not increase until a tilt angle of 10 degrees, with increments becoming significant beyond 15 degrees. These results demonstrated that MSNA plays an important role in hemodynamic regulation during incremental changes in posture, while tilt angle increased HR and other control mechanisms that may be involves.

Response to vestibular stimulation of sympathetic outflow to muscle in humans

The objective of the present study was to determine the effect of vestibular stimulation on the sympathetic outflow to muscle in humans. Fourteen healthy volunteers were studied while in the supine position with electrocardiography, blood pressure monitoring and electro-oculography. The muscle sympathetic nerve activity (MSNA) was recorded directly from the bilateral tibial nerves by using microneurographic double recording technique. Caloric vestibular stimulation was loaded by alternate irrigation with 50 ml of cold (10 degrees C) water and 50 ml of hot (44 degrees C) water into the left and right external meatus. After cold water irrigation, two MSNA response peaks were elicited, respectively, before and after the maximum slow phase velocity (SPV) of nystagmus. The first peak of the MSNA enhancement was caused by non-specific factors because its time course coincided with that in cold pressor test with immersion of the subject's hand in ice/water (4 degrees C). Transient suppression of MSNA after cold water irrigation in the period of maximum SPV of nystagmus was observed by cross correlogram analysis between the SPV of the nystagmus and MSNA. After hot water irrigation, only one MSNA response peak was elicited after the period of strong nystagmus. The second peak of MSNA enhancement evoked by cold irrigation (379.4 +/- 221.8%, with the control value set as 100%, mean +/- SE) was significantly higher than that evoked by hot irrigation (243.0 +/- 14.5%). The degree of MSNA enhancement by either cold (the second peak) or hot stimulation was proportional to the maximum SPV of the nystagmus. There was no significant difference between the MSNA responses ipsilateral to and contralateral to the irrigated side. In conclusion, the caloric vestibular stimulation can influence the bilateral sympathetic outflow to muscle in humans. The degree of MSNA enhancement is proportional to the magnitude of vestibular excitement indicated by maximum slow phase velocity of the nystagmus.

Skin sympathetic nerve activity in Guillain-Barré syndrome: a microneurographic study

To assess autonomic dysfunction, skin sympathetic nerve activity (SSNA) of four patients with Guillain-Barré syndrome was microneurographically studied in the acute and remission phase. Autonomic symptoms such as sinus tachycardia, palmar hyperhidrosis, hypertension, and orthostatic hypotension were present in the acute phase, but all subsided during remission. Basal resting SSNA and the responses to various physical and mental stimuli were all increased in the acute phase and returned almost to normal during remission. Rate of response in sweat rate and blood flow against SSNA were kept proportionally constant during both the acute and remission phases. These findings suggest that some autonomic nerve symptoms of Guillain-Barré syndrome, particularly during the acute phase, are due to increased SSNA.

The recruitment pattern of single vasoconstrictor neurons in human

The aim of this study is to determine the recruitment pattern among individual vasoconstrictor neurons under the baroreceptor-mediated influence in man. Spikes of single vasoconstrictor units were detected from microneurograms with a template-matching method. A total of 39 single vasoconstrictor units were detected. Single vasoconstrictor units were different from each other in their susceptibility to be activated in response to changes in the R-R interval or blood pressure. The units with higher firing probability had a shorter threshold R-R interval and a higher threshold diastolic blood pressure than units with lower firing probability. In sympathetic responses consisting of only one spike (single-spike responses), units with a lower threshold frequently appeared and units with a higher threshold joined mull-spike responses. The units with a short threshold R-R interval tended to have a long inhibitory latency from R wave, suggesting low conduction velocity. The correlation between firing probability and firing threshold and that between appearance in single-spike response and multi-spike response suggest a hierarchical manner of recruitment of vasoconstrictor units. For beat-to-beat responses, however, some deviation from the hierarchical recruitment was also observed.