Age-dependency of sympathetic nerve response to gravity in humans.
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Adolescent↗
Biomedical subjects
T Mano
Publications and source records attributed to T Mano.
Comparison of oxygen supply methods for cultures of shear-stress sensitive organisms including animal cell culture.
In animal cell culture, oxygen supply sometimes limits cell growth. Therefore, four oxygen supply methods (free surface aeration, porous Teflon tubing, perfluorocarbon addition and external aerator) were compared in terms of oxygen transfer rate for suspension culture of animal cells. Oxygen transfer rate with the free surface aeration was dependent on the vertical position of the impeller and the stirred Reynolds number for h/HL greater than 0.35, but no effect of the impeller position was observed for h/HL less than 0.35. The relationship between the Reynolds and Sherwood numbers could be expressed by simple correlations. These correlations could also be applied to oxygen transfer using porous Teflon tubing. When oxygen was supplied with perfluorocarbon saturated with air, the overall mass transfer coefficient KL was estimated to be about 9.0 X 10(-3) cm s-1, which was five-fold greater than that of the surface aeration. Maximum cell densities which would be supported by four methods were calculated from values of KLa for different sizes of fermentor assuming that oxygen supply would be the rate-limiting factor in animal cell culture.
Animals↗
Identification of sudomotor activity in cutaneous sympathetic nerves using sweat expulsion as the effector response.
In a warm environment at ambient temperatures between 25 degrees and 38 degrees C (relative humidity 50%-60%) the relationship between sympathetic activity in cutaneous nerves (SSA) and pulses of sweat expulsion was investigated in five young male subjects. The SSA was recorded from the peroneal nerve using a micro-electrode. Sweat expulsion was identified on the sweat rate records obtained from skin areas on the dorsal side of the foot, for spontaneous sweating and drug-induced sweating, using capacitance hygrometry. Sweat expulsion was always preceded by bursts of SSA with latencies of 2.4-3.0 s. This temporal relationship between bursts of SSA and sweat expulsion was noted not only in various degrees of thermal sweating but also in the sweating evoked by arousal stimuli, or by painful electric stimulation. The amplitude of the sudomotor burst was linearly related to the maximal rate of increase of the corresponding sweat expulsion, the amplitude of the expulsion and the integrated amount of sweat produced for the duration of the expulsion. The results provide direct evidence that sweat expulsion reflects directly centrally-derived sudomotor activity.
Adult↗
Skin sympathetic activity in the tibial nerve triggered by vibration applied to the hand.
The effect of vibration applied to the hand on skin sympathetic activity (SSA) in the lower limbs was studied in five healthy subjects. SSA from the right tibial nerve at the popliteal fossa, plethysmogram from the right index toe and perspiration from the sole of the right foot were measured when vibration of 100 m/s2 at 60 Hz was applied to the left palm for 1 min. The SSA response to vibration exposure differed among subjects, but every subject showed an increase in SSA from the tibial nerve when vibration was applied to the hand. Decrease in amplitude of plethysmogram from the toe was also found in all subjects. One subject displayed a remarkable increase in perspiration on the sole of the foot together with a great increase in SSA. The present findings indicated that even vibration exposure of the hand triggers sympathetic activity in the tibial nerve innervating the foot, and causes vasoconstriction of the toe and perspiration on the sole of the foot.
Adult↗
Changes in muscle sympathetic nerve activity and calf blood flow during static handgrip exercise.
To test the function of sympathetic vasco-constrictor nerves on blood flow in resting limbs during static muscle contraction, muscle sympathetic nerve activity (MSNA) to the leg muscle was recorded from the tibial nerve microneurographically before, during and after 2 min of static handgrip (SHG). Simultaneously, calf blood flow (CBF) was measured by strain gauge plethysmography. An increase in MSNA, a decrease in CBF and an increase in calf vascular resistance (CVR) in the same resting limb occurred concomitantly during SHG. However, the increase in CVR was blunted in the second minute of handgrip when MSNA was still increasing. The results indicated that the decrease of CBF during SHG reflects the increase in MSNA, while the dissociation between MSNA and CVR at the later period of SHG may be related to metabolic change produced by the vasoconstriction.
Adult↗
Thrombin stimulates the proliferation of human retinal glial cells.
Retinal glial cells may play a role in most of the proliferative retinopathies. Although glial cell proliferation is a frequent event in retinal pathobiology, no specific mitogens for human retinal glial cells are known. Using cultured retinal glial cells obtained from postmortem adult human eyes, we found that thrombin stimulates glial cell proliferation in a dose-dependent manner with a half-maximal concentration of 100 ng/ml (0.4 U/ml). Thus, thrombin may be a plasma-derived mitogen capable of stimulating retinal glial cells to proliferate when there is a breakdown of the blood-retinal barrier. We also observed that this proliferative response of retinal glia requires more than 6 h of continuous exposure to thrombin. This finding suggests that a thorough wash-out of a thrombin-containing infusate and/or the rapid inactivation of this molecule would prevent thrombin form exacerbating a proliferative disorder of the retina.
Adult↗
Heat-induced finger vasoconstriction controlled by skin sympathetic nerve activity.
Finger blood flow (BF) and skin sympathetic nerve activity (SSA) to the glabrous side of the hand were measured during immersion of the hand in a water bath in which temperature (Tw) was raised every 10 min by steps of 2 degrees C from 35 or 37 to 41 degrees C. The experiments were conducted during the summer in rooms in which ambient temperature was 28-32 degrees C or 35 degrees C. The nine healthy male subjects were wearing summer clothes. Finger BF through vessels located deep in the skin was measured by using laser-Doppler flowmetry (ALF-2100, Advance). With the use of a tungsten microelectrode SSA was recorded directly from the median nerve at the wrist or antecubital fossa of the tested arm. With finger vessels already dilated at Tw of 35 or 37 degrees C, finger BF decreased, with a concomitant increase in the SSA bursts as Tw rose to 39-41 degrees C. We confirmed in one subject that anesthetic blockade of the median nerve at the site proximal, but not distal, to the recording site blocked responses to the step rise in Tw in the SSA bursts and in finger BF. From these results we conclude that, with the subject in a warm state, blood vessels of the finger respond to local heating with vasoconstriction, and this finger vasoconstriction is evoked reflexively, largely through the increased sympathetic outflow to the resistance vessels of the finger.
Adult↗
Different responses in skin and muscle sympathetic nerve activity to static muscle contraction.
We microneurographically recorded the traffic of sympathetic nerves leading to foot volar skin activity (SSA) and leg skeletal muscle activity (MSA) during isometric handgrip and simultaneously determined sweat rate by the ventilated capsule method and skin blood flow by laser-Doppler flowmetry in the innervating area of SSA. SSA increased abruptly and was almost constant during handgrip, accompanied by an increase in sweat rate, whereas skin blood flow showed no significant change during the handgrip. MSA showed a time-dependent increase during the course of handgrip. During arterial occlusion of the working forearm after handgrip, SSA decayed to the precontraction control level, whereas MSA remained at a higher level than during control. During involuntary biceps muscle contraction induced by electrical stimulation, both SSA and MSA increased. The results suggest that the SSA response during voluntary handgrip, which was demonstrated to contain mainly sudomotor activity, might be influenced by central command and input from peripheral mechanoreceptors but be influenced little by input from muscle chemoreceptors.
Adult↗
1,25-Dihydroxyvitamin D3 antagonizes interferon-gamma-induced expression of class II major histocompatibility antigens on thyroid follicular and testicular Leydig cells.
Interferon-gamma (IFN gamma) induces production and expression of major histocompatibility complex class II molecules on both marrow-derived and nonbone marrow-derived cell types. 1,25-Dihydroxyvitamin D3 [1,25-(OH)2D3], a seco-steroid derived from vitamin D3, has previously been reported to enhance such expression alone or together with IFN gamma on a number of monocyte/macrophage tumorigenic lines. In contrast, the present studies have found that 1,25-(OH)2D3 inhibited the ability of IFN gamma to induce class II antigen expression on nontransformed rat thyroid follicular epithelial cells (FRTL-5) and mouse testicular Leydig cells (TM3). Although 1,25-(OH)2D3 inhibited the induction of both IA and IE class II locus products, IFN gamma augmentation of class I major histocompatibility complex antigens was not affected. 1,24-(OH)2D3 and 24,25-(OH)2D3 also inhibited class II induction by IFN gamma. Notably, the relative inhibitory ability of these compounds paralleled the strength of their binding affinities for the 1,25-(OH)2D3 receptor, indicating that this antagonistic effect probably requires receptor-ligand interaction. Other steroid hormones, such as hydrocortisone or testosterone, had no inhibitory effect on IFN gamma-induced class II expression on Leydig cells. Additionally, the failure of indomethacin to reverse the effect of 1,25-(OH)2D3 and the finding that exogenous prostaglandin E2 did not inhibit class II induction in these cells indicated that prostaglandins are probably not responsible for this anti-IFN gamma activity. In total, these results suggest that an endocrinological mediator is capable of inhibiting class II induction on resident endocrine tissue populations and, therefore, could help to diminish local CD4+ T-cell recognition of these cells.
24,25-Dihydroxyvitamin D 3↗
Preparation of fluorescence-labeled and cross-linked subtilisin.
Streptomyces subtilisin inhibitor (SSI) is a protein characterized by both its potent inhibitory activity toward subtilisin and its structure, composed of two homologous subunits. It binds two molecules of subtilisin to form a tetrameric complex. Intermolecularly cross-linked subtilisin is expected to form a polymeric complex with SSI. This could provide a useful model of protein-protein association. Therefore, preparation of fluorescence-labeled and cross-linked subtilisin was carried out.
Bacterial Proteins↗
Fluorescence labeled and cross-linked subtilisin: kinetic characteristics and binding to Streptomyces subtilisin inhibitor.
In the preceding paper, the preparation of fluorescent cross-linked subtilisin was described. In this paper we present the catalytic and binding properties of the modified enzyme. Kinetic analysis showed that the cross-linked dimeric subtilisin retained both catalytic activity and binding affinity toward synthetic substrates. These kinetic characteristics of the modified enzyme were nearly identical to those of the native enzyme. The modified enzyme also exhibited a specific interaction with Streptomyces subtilisin inhibitor (SSI) with 1 to 1 stoichiometry. The formation of a polymeric complex, which is the expected product with cross-linked subtilisin, was demonstrated.
Bacterial Proteins↗
[Mass urine glucose screening for asymptomatic diabetes mellitus in school children].
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Adolescent↗
Phagocytosis by human retinal glial cells in culture.
Under a variety of pathologic conditions, glial cells of the retina are capable of phagocytosis. Although phagocytosis may play a role in retinal pathobiology, the regulation of the phagocytic activity of retinal glial cells is poorly understood. We used a culture system to study phagocytosis by human retinal glial cells. The cultured cells were obtained from adult postmortem eyes and were immunoreactive to antibodies for glial fibrillary acidic protein and Muller cells. Electron microscopy demonstrated that the glial cells in culture were capable of phagocytosing fragments of retinal cells as well as latex beads. To rapidly quantitate phagocytosis, flow cytometry was used to detect glial cells that had internalized fluorescein-labeled microspheres. We found that reducing the extracellular calcium concentration decreased the phagocytic activity of the retinal glia. An inhibitory effect by nifedipine, a calcium channel blocker, on phagocytosis suggests a role for these ion channels in mediating a phagocytic response by retinal glial cells. A possible modulatory action of cyclic AMP was indicated by a decrease in phagocytic activity with exposure to 8-bromo-cyclic AMP. In addition to identifying conditions that reduce phagocytosis, we found that vitamin D3 can stimulate the phagocytic activity of retinal glia. Our experiments establish that phagocytosis by human retinal glial cells can be studied in a culture system and demonstrate that certain molecules can regulate the phagocytic activity of these cells.
8-Bromo Cyclic Adenosine Monophosphate↗
[Calf impedance plethysmographic evaluation of peripheral sympathetic nerve activity--comparison with microneurographic analysis].
Although the method of impedance plethysmography made it possible to evaluate the vascular resistance of lower extremities, the actual correlation to the sympathetic nerve activity is not known. We performed examinations of microneurography and impedance plethysmography of the lower extremities, in six healthy volunteers, placed on a tilting table. Blood pressure, heart rate, muscle nerve sympathetic activity to calf muscles (microneurography), calf vascular resistance (impedance plethysmography) were simultaneously recorded with increasing angles of the head-up tilting (0, 30, 60 degrees). With the increase of tilting angles, sympathetic nerve activity and the calf vascular resistance significantly increased and these values were statistically correlated to the increase of tilting angles (expressed as sine function). Moreover, a statistically significant positive correlation was observed between the sympathetic nerve activity and vascular resistance. We concluded that the impedance plethysmographic method for measurement of calf vascular resistance is a good indicator for evaluating the peripheral sympathetic nerve activity.
Adult↗
[A microneurographic analysis of minor reflex sympathetic dystrophy with increased skin sympathetic activity--report of a case].
A 48-year-old man developed swelling, redness, and allodynia in his left palm. Routine physical and neurological examinations revealed no abnormal findings except for left palmar hyperhidrosis. A clinical diagnosis of minor reflex sympathetic dystrophy with causalgia was made. Skin sympathetic activity (SSA), dominating palm sweating and skin vasoconstriction, and discharges of single afferent fiber from the rapidly adapting-type I (RA-I) unit were recorded microneurography from the median nerve at the cubital fossa. SSA obtained from the affected side was significantly increased compared with that from the normal (right) side. The receptive field of RA-I unit in this case was larger than those of normal controls. Enlargement of the receptive field might suggest presence of collateral sprouting in the injured nerve fibers. Allodynia in the left palm was suspected to be resulted from misdirect sprouting between A alpha . beta to A delta . C fibers. Excessive sympathetic out flow to the skin is considered to be the cause of palmar hyperhidrosis, swelling with redness, and lowered pain threshold, since pain threshold is under regulation of SSA. It is concluded that these sensory and autonomic symptoms were resulted from increased sympathetic out flow to the skin and collateral sproutings in the peripheral nerve fibers.
Humans↗
[Impedance plethysmographic evaluation of sympathetic activity to lower extremity].
Impedance plethysmographic analysis was performed in two cases of late cortical cerebellar atrophy (LCCA) and two cases of Shy-Drager syndrome. Blood pressure, heart rate and peripheral hemodynamics (arterial blood flow and vascular resistance of lower extremity) were measured during head-up tilting. In cases of LCCA, there was no decrease of blood pressure by tilting up. Impedance plethysmography showed significant increase in vascular resistance of lower extremity and heart rate was also increased. In cases of Shy-Drager syndrome, however, marked decrease of blood pressure was shown during tilting up, while there was no significant change in heart rate and vascular resistance of lower extremity was decreased. Therefore, in cases of Shy-Drager syndrome, decrease of peripheral sympathetic activity to lower extremity was suggested. Impedance plethysmography of lower extremity is simple, non-invasive and useful method to assess the status of peripheral sympathetic activity.
Aged↗
A rare case of recurrent vasodepressive attacks of 2-hours duration: analysis of the mechanism by muscle sympathetic nerve activity recording.
Muscle sympathetic nerve activity was recorded in a 57-year-old male patient suffering from severe hypotensive attacks with bradycardia for 10 years. Continuous blood pressure recording demonstrated frequent drastic falls in pressure. Disappearance and reappearance of muscle sympathetic nerve activity coincided with the onset and termination of attacks. Awakening from sleep or emotional and/or cardiovascular stress seems to trigger hypotension. Cardiac pacemaker was not useful in limiting the attack, because right ventricular pacing caused abrupt falls in both blood pressure and heart rate.
Bradycardia↗
Feeding cycles entrain circadian rhythms of locomotor activity in CS mice but not in C57BL/6J mice.
The effects of periodic, restricted feeding (RF) for two hours at a fixed time of day on the circadian rhythms of locomotor activity were examined in CS and C57BL/6J mice, kept under continuous dim, red lights (LLdim). In C57BL/6J mice, free-running rhythms were not affected by an RF schedule, although anticipatory behavior prior to the food access period was observed. On the other hand, the free-running rhythms of CS mice did entrain to an RF schedule, exhibiting anticipatory behavior. The free-running rhythms of none of the control animals in either strain exhibited any effects resulting from the periodic disturbances occurring concurrently with the performance of RF. These results indicate that the circadian pacemaker couples with the food entrainable oscillator (FEO) in CS mice, but that such coupling may not exist, or may be very weak, in C57BL/6J mice.
Animals↗