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Biomedical subjects

S Iwase

Publications and source records attributed to S Iwase.

At least 163 records · Page 9Linked to original sources
PubMed1989

Sympathetic nerve activity related to local fatigue sensation during static contraction.

The relationship between autonomic nervous activity and psychophysical responses was studied during static exercise in humans. Muscle sympathetic nerve activity (MSNA) recorded by a direct method of microneurography and the intensity of fatigue sensation in working muscles [levels of fatigue sensation (LFS) scale 0-10] were analyzed in 11 male subjects during static handgrip (SHG). SHG was exerted at a tension of 25% of maximal voluntary contraction until the given tension could no longer be sustained. MSNA, represented as total activity (burst number x mean burst amplitude), and LFS increased in a time-dependent process till the end of the SHG. At the termination of the static exercise MSNA had increased an average of 480% of the resting value. In the simple exponential curve, Y = A expBX, where X was LFS and Y was MSNA. The constants A and B estimated from the total experiments were 84.5 and 0.161, respectively. The correlation between LFS and MSNA was statistically significant. There was a large difference in the value of constant B (0.089-0.278) among the subjects, and a relatively small difference in the value of constant A (37.5-133.8). The increases in both MSNA and LFS during SHG may be mainly related to the same afferent volley from working skeletal muscles. The results indicate that the response of the muscle sympathetic nerve to SHG relates to the psychological feelings of fatigue in the working muscles.

Adult↗
PubMed1989

[Progressive hemifacial atrophy with sympathetic nerve dysfunction of central origin].

A 37-year-old unmarried man was admitted because of gait disturbance and right hemifacial atrophy. Family history was unremarkable. He had an unconscious attack at age 13 and had writer's cramp since age 15. He was thin and lipodystrophic. In reviewing his portraits, hemifacial atrophy was considered to develop in his early teens and to be progressive since then. Pigmented gum, high arched palate, mild mental retardation, pseudo-Argyll Robertson's pupil, sexual impotence, amyotrophy of the left thigh and the right calf, and a limp due to bony abnormalities was detected. Serological tests for syphilis were negative. Bone X-rays disclosed coxa-deformance. Cerebrospinal fluid. EMG, EEG, muscle biopsy and brain CT were normal. Hearing was decreased to 20-35 dB bilaterally. Plasma norepinephrine levels were 450 pg/ml in the supine position and 539 pg/ml in standing. Plasma renin activity was 5.1-5.4 ng/ml/hr. Microneurography revealed highly accentuated muscle and skin sympathetic nerve activities. Hypothermia on the feet, reduced CVR-R and decreased mydriatic response to 5% cocaine instillation were present. Intravenous infusion of norepinephrine and intradermal injection of either acetylcholine or histamine revealed normal results. In the case, sympathicotonia due to dysfunction in the central nervous system is considered to be related to the pathogenesis of hemifacial atrophy.

Adult↗
PubMed1989

[Clinical analyses on moving toes in "painful legs and moving toes"].

Clinical analyses on moving toes were done through two cases of painful legs and moving toes, who had been ill for more than 5 years. Either cases had degenerated lower lumber to upper sacral spines. Clinico-physiological data suggested the presence of polyneuropathy of the sensory type. They showed the lowered skin temperature on the distal portions of lower extremities and acrocyanosis. They, in addition, showed an irregular respiration frequently associated with apnea episodes. Frequency and amplitude of moving toes were increased during Valsalva's maneuver or apnea. Further more, findings were obtained that both the muscle sympathetic nerve activity recorded microneurographically from the tibial nerve and the surface electromyographic activity on the extensor digitorum longs were increased well concomitantly by the occurrence of moving toes. The finding may relevant that moving toes, a type of dyskinesia, may be probably generated by a direct noxious stimulus to the peripheral sensory or autonomic fibers, being strongly influenced by the higher central autonomic (at brain stem?), the extrapyramidal (at corpus striatum?) or some other structures. Moving toes might be a compensatory mechanism to lessen the paucity of blood flow in the lower extremities.

Aged↗
PubMed1988

Analysis of water-soluble vitamins by micellar electrokinetic capillary chromatography.

Seven water-soluble vitamins were determined simultaneously by micellar electrokinetic capillary chromatography with UV detection. All these compounds were separated from each other within ca. 22 min by using a carrier containing sodium dodecyl sulphate as the surfactant. On-column detection at 254 nm with ethyl p-aminobenzoate as the internal standard allowed sensitive, accurate and reproducible determination of these compounds. Five principal constituents of a vitamin injection were determined with relative standard deviations of less than 2.1%.

Chromatography↗
PubMed1988

Responses in muscle sympathetic activity to acute hypoxia in humans.

Responses in muscle sympathetic activity (MSA) to acute hypoxia were studied in 13 healthy male subjects under hypobaric hypoxic conditions at a simulated altitude of 4,000, 5,000, and 6,000 m. Efferent postganglionic MSA was recorded directly with a tungsten microelectrode inserted percutaneously into the tibial nerve. Heart rate (HR) and respiratory rate (RR) were counted respectively from the R wave of an electrocardiogram and from the respiratory tracing recorded by the strain-gauge method. The average values of the MSA burst rate and total activity of MSA (burst rate x mean burst amplitude) at 4,000, 5,000, and 6,000 m were 36.4 +/- 2.6, 39.1 +/- 3.1, and 40.2 +/- 4.2 (SE) bursts/min and 616 +/- 138, 794 +/- 190, and 764 +/- 227 arbitrary units, respectively. These values were significantly higher than the values of 27.1 +/- 2.9 bursts/min and 446 +/- 28 at sea level. HR increased significantly at altitudes, but RR did not show significant change. Under severe hypoxic conditions beyond 5,000 m, there were large interindividual differences in the MSA responsiveness to hypoxia. The results indicate that MSA is activated under hypoxia by stimulating the chemoreceptors. However, the central controlling mechanisms that would be affected by hypoxia may also influence the MSA responsiveness under severe hypoxia.

Adult↗
PubMed1988

Effect of L-threo-3,4-dihydroxyphenylserine on muscle sympathetic nerve activities in Shy-Drager syndrome.

We observed changes in postganglionic efferent discharges of muscle sympathetic nerve (muscle sympathetic activity, MSA) microneurographically before and after the oral administration of L-threo-3,4-dihydroxyphenylserine (L-threo-DOPS), a precursor of norepinephrine, in a patient with Shy-Drager syndrome and irregular fluctuations of blood pressure. Before drug administration, MSA was only rarely observed with the patient in the supine position. There was a slight increase in MSA during head-up tilting to 40 degrees, and orthostatic hypotension (OH) occurred just after the body was tilted head upward to 40 degrees. MSA became prominent 30 minutes after the oral administration of 200 mg of L-threo-DOPS while the patient was in a 40 degree head-up position, and the OH was improved. The MSA discharge rate decreased and OH reappeared 3 hours after oral administration, when the plasma concentration of norepinephrine was at its highest level. We suggest that the OH improved mainly because of the increase in MSA due to L-threo-DOPS, and that the drug may activate sympathetic outflow at a site proximal to the sympathetic ganglion.

Autonomic Nervous System Diseases↗
PubMed1987

Fluorometric determination of sialic acids using malononitrile in weakly alkaline media and its application to postcolumn labeling in high-performance liquid chromatography.

A sensitive method for determination of sialic acids by monitoring the fluorescence produced with malononitrile in borate buffer has been established. Measurement of the fluorescence intensity of the reaction mixture at 430 nm with irradiation at 360 nm allowed determination of 3-60 nmol of sialic acids with high reproducibility. A few amino sugars and deoxy sugars, as well as catecholamines reacted with this reagent; however other carbohydrates, amino acids, amines, aldehydes, and carboxylic acids including alpha-keto acids, etc., showed little reactivity. This method was successfully applied to postcolumn fluorescence labeling of sialic acids in high-performance liquid chromatography.

Animals↗
PubMed1987

Diagnostic/prognostic significance of photo-evoked eyelid microvibration in neonates with intracranial hemorrhage.

Photo-evoked eyelid microvibration (PEMV) was recorded in neonates with intracranial hemorrhage in order to determine whether it serves as a useful indicator of clinical course and also prognosis. Although the latency of PEMV was prolonged or absent in the acute stage of ICH, it returned to a normal range in these subjects with the improvement of symptoms. Three infants whose PEMV were still prolonged in the convalescent stage developed mental retardation or cerebral palsy. PEMV may be a useful predictor of the prognosis of neonatal ICH and its prolongation may signal later neurological sequelae.

Blinking↗
PubMed1987

Transdiaphragmatic duodenal duplication in a premature infant.

A case of transdiaphragmatic duodenal duplication in a premature infant is presented. Vertebral abnormalities, which have invariably accompanied this disorder in reported cases so far, were characteristically absent. Therefore, the initial tentative diagnosis was right-sided diaphragmatic hernia. Barium examination was helpful in preoperative diagnosis.

Barium Sulfate↗
PubMed1987

Longitudinal determination of cerebral blood flow velocity in neonates with the Doppler technique.

Using the Doppler technique, we followed the postnatal changes of the cerebral blood flow velocity longitudinally. Pulsatility index (PI) was measured in 91 neonates. In 26 normal term infants who were supine, PIs were initially raised (PI = 0.91 +/- 0.10), gradually falling over the first 12 hours after birth and remaining stable thereafter (PI = 0.78 +/- 0.05). PIs tended to be lower in neonates born by caesarean section but remained grossly within the normal range. Low birthweight infants showed high PIs during the first 12 hours after birth. Infants with a prone position showed a narrow standard deviation in PI soon after birth. There was a negative correlation between PI and the conceptional age and the coefficient of the correlation was 0.97156. The stage of active sleep, especially the REM period, was found to be an important factor which decreased the PI. We concluded that neonatal cerebral circulation significantly changes during the perinatal period and is affected by various physiological factors, especially sleep stages, the position of the infant and the conceptional age.

Blood Flow Velocity↗
PubMed1987

Plasma atrial natriuretic peptide and spontaneous diuresis in sick neonates.

Plasma concentrations of immunoreactive human atrial natriuretic peptide (human ANP) were sequentially determined in 12 infants with respiratory distress syndrome (RDS) or meconium aspiration syndrome (MAS) during various phases of diuresis to elucidate the role of human ANP in the occurrence of spontaneous diuresis in the newborn. Plasma immunoreactive ANP concentrations during the diuretic as well as the maximum diuretic phase were significantly (p less than 0.001) higher than during the prediuretic phase. A gradual decrease occurred during the post diuretic phase, returning to prediuretic values after one week of life. Significant natriuresis, increased glomerular filtration rate, mild hyponatremia, and decreased blood pressure were observed in the diuretic phase in all the cases studied. These results suggest that hypersecretion of human ANP may play an important part in initiating spontaneous diuresis in sick neonates.

Atrial Natriuretic Factor↗
PubMed1987

Reliability of urinary N-acetyl-beta-D-glucosaminidase as an indicator of renal tubular damage in neonates.

Urinary N-acetyl-beta-D-glucosaminidase (NAG) was determined in infants during the first year of life to clarify its evolutional change and the reliability of this enzyme as a marker of renal tubular damage in the newborn period. During the first 2 weeks of life, there was no difference in the urinary levels between preterm (gestational age of 33-36 weeks) and full-term infants. The urinary NAG index (NAG is expressed as the ratio of the enzyme activity to milligrams of creatinine) during the first month of life was significantly elevated when compared with that of any other succeeding period and gradually decreased during the first year of life. The index in newborn infants on tobramycin was significantly elevated and maintained a higher value during the 5 days after withdrawal of the medication. Infants with asphyxia had a higher urinary NAG index during the first week of life. These data suggest that the urinary NAG index is a useful indicator of renal tubular damage during the newborn period.

Acetylglucosaminidase↗
PubMed1986

Responses in muscle sympathetic nerve activity to sustained hand-grips of different tensions in humans.

To clarify whether sympathetic nerve activity increases in relation to the tension of a sustained muscle contraction, muscle sympathetic nerve activity (MSA) was recorded directly from the peroneal nerve fascicle at the popliteal fossa by means of tungsten microelectrodes in five healthy male subjects. A sustained muscle contraction was performed by handgrip for two minutes in a supine position at tensions of 10, 30 and 45% of maximal grip strength (MGS). MSA, electrocardiogram (ECG) using bipolar electrodes from the chest and surface electromyogram (EMG) from the extensor pollicis longus were recorded simultaneously before and during the sustained handgrip. Arterial blood pressure was measured at the resting upper arm by auscultation. During handgrip with tensions of 10, 30 and 45% MGS, average MSA burst rate (bursts X min-1) increased to 122, 152 and 230% of the resting value, respectively. During the same experimental procedures with tensions of 10, 30 and 45% MGS, average heart rate increased to 105, 110 and 111% of the resting value. These results confirm that sympathetic outflow to a resting muscle is increased with elevation of tension in an active muscle. This process would promote perfusion pressure in the active muscle.

Adult↗
PubMed1986

Auditory brainstem response in neonates with asphyxia and intracranial haemorrhage.

Auditory brainstem response (ABR) was used to assess possible brainstem damage in 76 neonates with asphyxia and intracranial haemorrhage (ICH). Fifty-eight neonates had ICH, 52 had neonatal asphyxia and 34 of these patients had both. Eighty-nine percent of the patients with neonatal asphyxia showed some abnormal patterns in response, the major one being an increase in the threshold of wave V. In the ICH group, abnormal patterns were observed in 62.5%, among whom the prolongation of the I-V interpeak latency (IPL) and of wave V latency was seen more frequently than the increase of threshold of wave V. In the case of neonatal asphyxia associated with ICH, both the prolongation of the latency and the increase of threshold were observed equally. These abnormalities of ABR were associated with worsening clinical condition and conversely normalized gradually following the improvement of the underlying disease. Especially the I-V IPL, wave V latency and the threshold of wave V could serve as indicators of the treatment.

Asphyxia↗
PubMed1986

Unusual cases of presenile dementia with Fahr's syndrome.

Three patients with an unusual type of presenile dementia were studied. Atypical clinical pictures emerged from an evaluation of these cases. Their symptoms and signs were thought to be neither those of Alzheimer's disease nor those of Pick's disease but a partial mixture of those of both diseases. The neuropathological changes were characteristic and the common findings were as as follows: the absence of senile plaques, the widespread presence of numerous neurofibrillary tangles, a calcareous deposition of Fahr's type, a circumscribed cerebral atrophy in the temporal or/and frontal lobes, a moderate or severe demyelination and fibrous gliosis in the white matter of the atrophied areas, and a slight or moderate neuronal loss in the nucleus basalis of Meynert. Similar cases reported previously were reviewed.

Brain Diseases↗
PubMed1986

Different responses of muscle sympathetic nerve activity to sustained and rhythmic handgrip exercises.

Muscle sympathetic nerve activity (MSA) was recorded by microneurographic technique from the human tibial nerve before and during voluntary sustained and rhythmic handgrip exercises. The MSA increased significantly during sustained contractions but not during rhythmic contractions, whereas no differences in resting activity before the two modes of handgrip were seen at rest. The results demonstrate that MSA responses to sustained and rhythmic exercises are distinctly different, showing less sympathetic outflow during rhythmic than during sustained contraction.

Blood Pressure↗