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Biomedical subjects

T Mano

Publications and source records attributed to T Mano.

At least 235 records · Page 13Linked to original sources
PubMed1992

Isolated IgA deficiency accompanied by autoimmune thyroid disease.

Selective immunoglobulin (Ig) A deficiency is reported to occur in 1 in 16,000 in Japan and has been reported to be complicated with various autoimmune diseases. A 49-year-old woman was diagnosed as having autoimmune thyroid disease. Her serum IgA, IgM and IgG were revealed to be 4.1, 154 and 1930 mg/dl, respectively. Severe skin eruption which occurred with 30 mg/day of methimazole (MMI) or 300 mg/day of propylthiouracil (PTU), was relieved by reducing MMI to 15 mg/day and administering anti-allergic drugs. Although the influence of IgA deficiency on autoimmunity and allergy still remains unclear, this is a report of IgA deficiency associated with autoimmune thyroid disease.

Autoimmune Diseases↗
PubMed1992

Responses of muscle sympathetic nerve activity and cardiac output to the cold pressor test.

We measured muscle sympathetic nerve activity (MSA) to clarify the mechanisms of the blood pressure rise during cold pressor test (CPT), simultaneously with impedance cardiography and blood pressure wave measurement in 10 healthy subjects. MSA remained unchanged during the initial period of 0-30s of the CPT and increased remarkably during the later period of 30-90s of the CPT, while cardiac output exhibited a slight increase during the initial period but not during the later period. Mean blood pressure increased significantly throughout the entire period of CPT and reached the maximal level during 90-120s of the CPT. The mean blood pressure and total peripheral resistance during the CPT showed a linear correlation with MSA. In conclusion, an increase of cardiac output elevates blood pressure at the initial period of the CPT with little increase in MSA, while an increase of MSA plays an essential role to elevate the blood pressure at the later period of the CPT.

Adult↗
PubMed1991

[A case of two successful deliveries by a woman with Kallmann syndrome and NIDDM].

A 37 year-old female with Kallmann syndrome and NIDDM who had two successful deliveries is reported. She had experienced no menstruation until she had treatment with gestagen in her early twenties. She had withdrawal bleeding only once. At the age of 25, she consulted her family doctor, complaining of amenorrhea. Estrogen progesterone cyclic therapy caused withdrawal bleeding, and clomiphene citrate failed to induce apparent ovulation. In January 1978, 150 IU of hMG was administered daily for 9 days, and then 3000 IU of hCG daily for the following 2 days. This therapy induced pregnancy, which failed spontaneously on June 4th. A year later, in January 1979, 150 IU of hMG was again administered daily for 7 days followed by 6000 IU of hCG for 3 days. This therapy again induced pregnancy. On September 27th, 1979, she delivered a girl vaginally, weighing 3830 g. After this delivery, she experienced no menstruation. In June 1985, she consulted her family doctor again, and she was diagnosed as being pregnant. Since her fasting blood glucose was 145 mg/dl, she was admitted to Kosei Hospital to control her blood glucose. On October 15th, she delivered a girl weighing 2600 g. On June 13th, 1989, she was referred to Kosei Hospital by her family doctor to achieve an accurate control of her blood glucose. During this admission, she was diagnosed as having Kallmann syndrome because of congenital anosmia and hypogonadotropic hypogonadism without any abnormal morphological changes. Vitamin B1 infusion test was negative.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Interferon-gamma induces the expression of major histocompatibility antigens by human retinal glial cells.

Retinal glial cells normally do not express major histocompatibility (MHC) molecules. However, the expression of MHC antigens by retinal glial cells under certain pathological conditions suggests that these cells may play a role in immune responses of the retina. At present, the identity of molecules that may regulate the expression of class I and class II MHC antigens by retinal glial cells has not been established. Since interferon-gamma (IFN-gamma) induces MHC antigens in a variety of cell types, we examined the effect of this lymphocyte product on class I and class II antigen expression by human retinal glial cells in culture. Glial cells derived from post-mortem donor eyes were exposed to recombinant human IFN-gamma. Cells with MHC class I or class II antigens were detected with the use of specific monoclonal antibodies that were labeled directly or indirectly with fluorescent probes. Fluorescence of labeled cells was assayed by flow cytometry. Exposure to IFN-gamma increased the expression of class I and class II antigens by the retinal glial cells. Double labeling studies showed that 90% of the glial cells induced to express class II antigens also had class I antigens. Overall, the results show that IFN-gamma can regulate the expression of MHC molecules by human retina glial cells in culture. These findings are consistent with the concept that glia may play a role in immunological disorders affecting the retina.

Adult↗
PubMed1991

Neural and humoral controlling mechanisms of cardiovascular functions in man under weightlessness simulated by water immersion.

To clarify how neural and humoral mechanisms operate to control cardiovascular functions in man under weightlessness, the response of sympathetic nerve activity was observed in healthy human subjects by means of microneurographic technique with the changes of several hemodynamic parameters and hormonal responses during thermoneural head-out water immersion. Muscle sympathetic nerve activity was markedly suppressed by head-out immersion, concomitantly with a reduction of the leg volume, an increase of the stroke volume and a reduction of total peripheral resistance. At the same time, plasma level of norepinephrine, vasopressive and antidiuretic hormones (ADH, aldosterone, renin activity, angiotensin I-II) were reduced, while vasodepressive and diuretic hormone (ANP) was markedly increased. The systemic blood pressure was maintained almost unchanged during head-out water immersion. The suppressive response of sympathetic nerve activity seemed to be age-dependent. This response was less prominent in the elderly than in young subjects. It is concluded that the suppressive response of muscle sympathetic activity plays an important role to maintain hemodynamic homeostasis under weightlessness to compensate for the cephalad fluid shift and the resultant increase of the stroke volume in cooperation with the hormonal responses.

Adolescent↗
PubMed1991

Telescience testbed in human space physiology.

The present telescience testbed study was conducted to evaluate the feasibility of physiological experimentation under restricted conditions such as during simulated weightlessness induced by using a water immersion facility, a reduced capacity of laboratory facilities, a delay and desynchronization of communication between investigator and operator, restrictions of different kinds of experiments practiced by only one operator following a limited time line and so on. The three day's experiments were carried out following the same protocols. The operators were changed every day, but was the same the first and the third day. The operators were both medical doctors but not all round experts in the physiological experimentation. The experimental objectives were: 1) ECG changes by changing water immersion levels, 2) blood pressure changes, 3) ultrasonic Echo-cardiographic changes, 4) laser Doppler skin blood flowmetry in a finger, 5) blood sampling to examine blood electrolytic and humoral changes. The effectiveness of the testbed experiment was assessed by evaluating the quality of the obtained data and estimating the friendliness of the operation of the telescience to investigators and operators.

Aerospace Medicine↗
PubMed1991

Comparison between muscle sympathetic nerve activity and calf vascular resistance with head-up tilting in humans.

The purpose of this study was to determine the relationship between muscle sympathetic nerve activity (MSA) to calf muscle and calf vascular resistance with head-up tilting in humans. In nine healthy volunteers, we performed simultaneous measurements of MSA using microneurography and calf vascular resistance using electrical impedance plethysmography in the same leg. The volunteers were laid on a tilt table and the examinations with head-up tilting (0 degrees, 30 degrees, 60 degrees) were performed. Corresponding to the increase in angles of head-up tilting, MSA and calf vascular resistance significantly increased. A statistically significant positive linear correlation was demonstrated between MSA and calf vascular resistance. These data suggest that impedance plethysmographic measurement of calf vascular resistance can be reliably used to assess the status of MSA with head-up tilting.

Adult↗
PubMed1991

Long-acting alpha 1-adrenoceptive sympathomimetic agent suppresses sympathetic outflow to muscles in humans.

To clarify the effect of a long-acting selective alpha 1-adrenoceptive sympathomimetic agent on sympathetic outflow to muscles (muscle sympathetic activity, MSA) in humans, 5 mg of midodrine hydrochloride was injected intravenously in ten healthy male subjects aged 19-25. Spontaneous MSA was significantly suppressed as well as plasma norepinephrine level without changing heart rate, or systemic blood pressure. The suppression continued for more than 90 min, and this is supposed to be due to negative feedback action on the baroreflex loop. The absence of significant changes in heart rate or systemic blood pressure in healthy subjects suggests that hemodynamic homeostasis is maintained by reducing the MSA in response to a long-acting sympathomimetic agent, like midodrine hydrochloride, which constricts peripheral vessels directly.

Adrenergic alpha-Agonists↗
PubMed1991

Age-related changes of sympathetic outflow to muscles in humans.

Muscle sympathetic nerve activity (MSA) was recorded microneurographically from the tibial nerve in 40 healthy male subjects aged 18 to 75. Passive and graded head-up tiltings were loaded on the subjects. The effects of aging on the resting activity of muscle sympathetic nerve in supine position at rest (burst number per minute), increase in MSA from the resting level by orthostasis (slope of the regression line between sine of the tilt angle and MSA bursts per minute), and the MSA in upright standing position were analyzed. The resting MSA increased with age, and a significant positive correlation was observed between age and resting activity (Y = -6.83 +/- 0.876X, r = .882, p less than .001). The MSA was enhanced by head-up tilt linearly with the sine of the tilt angle, and a significant negative correlation was observed between age and the MSA increase by orthostasis (Y = 57.6 - 0.582X, r = . 843, p less than .001). Standing MSA increased significantly but less remarkably than resting MSA. It was concluded that aging increases the resting activity, but there is less increase in the standing activity of sympathetic outflow to muscles in humans.

Adolescent↗
PubMed1991

Changes in muscle sympathetic nerve activity during sleep in humans.

We microneurographically recorded muscle sympathetic nerve activity (MSA) during sleep in 12 healthy volunteers while simultaneously recording EEG, EOG, ECG, respiration, and blood pressure and determined the number of pulse-synchronous MSA bursts per minute (burst rate) for non-rapid eye movement (nonREM) sleep and rapid eye movement (REM) sleep. MSA decreased during nonREM sleep with progressively deeper sleep stages. During REM sleep, the burst rate of MSA increased and was associated with marked fluctuations in arterial blood pressure. During sleep stage 2, MSA bursts occurred approximately 1 second after spontaneous K-complexes. We conclude that (1) the decreases in MSA during nonREM sleep stages may indicate sleep-stage dependent central suppression of MSA activity; (2) increases in MSA during REM sleep suggest instability of the autonomic nervous system; and (3) a common pathway may exist for MSA bursts and K-complexes.

Adolescent↗
PubMed1991

Postprandial hypotension: microneurographic analysis and treatment with vasopressin.

To clarify the mechanism of postprandial hypotension (PPH), we made microneurographic analyses of patients with PPH and 10 healthy controls by recording multi-unit vasoconstrictive impulses of muscle sympathetic nerve activity (MSNA) directly from the tibial nerve fascicles during a glucose tolerance test. Oral intake of 75 grams glucose in 225 ml of water produced significant and prolonged hypotension in all patients and an increase in MSNA in all healthy subjects. Insulin and glucose responses were not significantly correlated with arterial blood pressure reduction. PPH was prevented by an infusion of vasopressin (0.3 U/min) given before glucose intake. These results suggest that PPH is caused by the lack of sympathetic compensation for the systemic hypotensive stress of splanchnic blood pooling that occurs after food ingestion, and that prior treatment with vasopressin reduces the portal venous flow by constricting the splanchnic vessels in patients with PPH.

Adult↗
PubMed1991

Exercise mode affects muscle sympathetic nerve responsiveness.

To compare the responses of remote sympathetic nerves to dynamic and static leg exercises, we recorded sympathetic nerve activity leading to skeletal muscle (MSNA) using a tungsten microelectrode during one-leg cycling at loads of 0, 25, and 50 W and during static leg extension (SLE) at 20% of maximal voluntary contraction. Oxygen uptake (Douglas bag method) and local fatigue sensation (LFS) of the working muscle were measured during cycling and SLE. MSNA decreased from the control value, respectively, by 25, 21, and 12% during cycling at loads of 0, 25, and 50 W. The differences from the control value were significant except during cycling at 50 W. On the contrary, MSNA increased from the control value by 83% during SLE. Oxygen uptake during 25 and 50 W leg cycling was greater than during SLE, whereas LFS was higher during SLE than during leg cycling at any load. The results indicate that the response of muscle sympathetic nerves to exercise does not exclusively reflect whole body metabolism, but is instead related to the local metabolic changes.

Adult↗
PubMed1991

Muscle sympathetic nerve responsiveness to static contraction is not altered under hypoxia.

The purpose of this study was to determine if response in muscle sympathetic nerve activity (MSNA) to static muscle contraction alters or not during peripheral chemoreceptor stimulation with hypoxia. MSNA was recorded from the tibial nerve using a microneurographic technique in seven healthy subjects in a sitting position. They performed a static handgrip exercise (SHG) for 2 min under normobaric normoxia and hypobaric hypoxic conditions corresponding to an altitude of 4,000 m (460 mmHg). MSNA represented as burst rate and total sympathetic nerve activity (TSNA) (burst rate X mean burst amplitude) at rest increased by 7.7 bursts/min and by 60%, respectively, compared to those under normoxia. During the exercise, MSNA increased over control values before exercise both under normoxia and hypoxia. TSNA increased during the first and second minute of SHG by 19% (p greater than 0.05) and 35% (p less than 0.05) in normoxia and by 15 (p greater than 0.05) and 34% (p less than 0.05) in hypoxia over the control value, respectively, while the absolute intensity of MSNA during SHG was higher under hypoxia. The response of MSNA to SHG which showed algebraic sums was the same under normoxia and hypoxia, that might relate to consist of afferent pathways independent from carotid chemoreflex.

Adult↗
PubMed1991

Modulation of calcium channels in human retinal glial cells by basic fibroblast growth factor: a possible role in retinal pathobiology.

The objective of this study was to begin to examine the cellular and biophysical effects on human retinal glial cells of basic fibroblast growth factor (bFGF), which is endogenous to the retina and likely to play a role in retinal pathobiology. Experiments were performed on cultured glial cells derived from the adult postmortem retina. A proliferative response to bFGF established a sensitivity of the retinal glia to this growth factor. The possibility that bFGF alters calcium currents was assessed using the whole-cell recording configuration of the patch-clamp technique to analyze inward currents carried by barium. Two types of voltage-gated calcium channels could be expressed by the glial cells. One, similar to the T-type current described in various kinds of cells, had a low threshold of activation, a transient response, and an insensitivity to the dihydropyridine nifedipine. The other type of inward current, which closely resembles the L-type calcium current found in other cells, had a high threshold, had a long-lasting response, and was inhibited by nifedipine. When continuous whole-cell recordings were made from retinal glial cells, the L-type calcium current increased significantly within 20 min after exposure of the cells to bFGF. The physiological significance of this modulatory effect remains uncertain, though the observation that nifedipine inhibits both the L-type calcium current and the bFGF-induced proliferation is consistent with the hypothesis that dihydropyridine-sensitive channels may play a role in modulating the mitogenic response of retinal glial cells to this growth factor.

Adult↗
PubMed1991

[Sympathetic nerve activity in amyotrophic lateral sclerosis--analysis by microneurography].

Muscle sympathetic nerve activity (MSA) was quantitatively analyzed in amyotrophic lateral sclerosis (ALS) by using microneurography. Studies were conducted in 10 ALS patients (2 males, 8 females; mean age 56.4 SD 17.3 years; range 31-77 years). The duration of the disease after onset of symptoms was from 0.8 to 2.5 years. They were classified as a type of classical ALS having mild degree of bulbar signs, an ability to walk by themselves and no subjective breathing impairment. Control groups were selected from 16 healthy age-matched volunteers (8 males, 8 females; mean age 52.9, SD 15.5 years; range 29-76 years). MSA was recorded directly from peroneal nerve fascicles at the popliteal fossa by means of tungsten microelectrodes. The changes in MSA, blood pressure and heart rate were analyzed in the ALS groups and controls laid at recumbent and 30 degrees head-up tilted positions. The parasympathetic functions were evaluated by CVR-R and baroreflex latency. MSA bursts/minute, bursts/100 heart rate and total MSA at recumbent position were significantly higher (p less than 0.01), but their changes at 30 head-up tilted position were slightly lower in the ALS groups compared with the controls. Furthermore, a linear correlation between age of the subjects and MSA in the controls was not found in ALS groups. There were no differences between both groups in blood pressure and heart rate at the two positions. The parasympathetic function was normal in ALS groups. In ALS, sympathetic hyperfunction independent of cardiovascular systems was found especially at the recumbent position. These findings were considered specific to ALS, but the etiology was unclear.

Adult↗
PubMed1991

[Effects of muscle relaxant E-0646 on human stretch reflex and responses].

The experiment examined the effects of a muscle relaxant E-0646 on short latency stretch reflex (SLR) and long latency stretch responses (LLRs) of lower leg muscles in 5 healthy male subjects, aged 24-41 years. An AC servomotor produced an ankle rotation of comfortably seated subjects in the direction to stretch the triceps surae muscle for the SLR and the tibialis anterior muscle for the LLRs. Following control measurements, after the oral administration of 50, 100, 150, and 300 mg of E-0646, the SLR and LLRs were recorded every 2 hours for 4 or 6 hours with simultaneous blood sampling to measure E-0646 plasma levels. Electromyograms (EMGs) of the soleus and tibialis anterior muscles were recorded with surface electrodes on each muscle belly. A precision potentiometer was used to measure the ankle angle. The soleus SLR, evoked by a torque pulse (7 msec duration) of one of 5 different amplitudes, decreased 2 hours after the 300 mg administration. A SLR decrease was also found in a simple relationship between the integrated SLR EMG and the angular velocity at 20 msec after the torque onset, in which the slope and intercept of the relationship changed. The plasma E-0646 level roughly correlated with the SLR decrease. No significant change of the SLR was observed when dosage was less than 150 mg. The LLRs of the tibialis anterior muscle were tested under the instruction "resist when perturbed" during a weak isometric contraction against a constant plantar flexion torque.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Low frequency components of the body's center of gravity and blood circulation.

The purpose of this study was to clarify how low frequency components of the body's center of gravity, mainly 1 minute waves (1-MWs), are related to the mechanism of compensation for the venous blood pooling in the legs during static standing in humans. The 1-MWs of foot pressure center, oscillations of body circumferences and other parameters were analyzed with cross-power spectral analysis. The 1-MW of the calf's blood volume propagated to the chest via the venous system. This was inversely synchronized with the 1-MW of the body's center of gravity. It was speculated that muscular pumping of the calf related to the 1-MW of the body's center of gravity might be compensating for the venous blood pooling in the legs.

Adult↗