Effect of hypercapnia and hypoxia on arytenoideus muscle activity in normal adult humans

The electrical activity of the arytenoideus muscle, a vocal cord adductor, was measured in 14 normal adult humans during progressive isocapnic hypoxia and progressive hyperoxic hypercapnia. Electromyograms of the arytenoideus were obtained with intramuscular hooked-wire electrodes implanted by means of a fiber-optic nasopharyngoscope. Correct placement of the electrodes was confirmed by discharge patterns during voluntary maneuvers. In three of the subjects, respiratory-related arytenoideus activity was not present during quiet breathing or chemical stimulation. During quiet breathing in the 11 other subjects, the arytenoideus exhibited phasic activity during expiration and usually tonic activity throughout the respiratory cycle. Phasic and tonic arytenoideus activity decreased under hypoxic and hypercapnic conditions. At higher levels of chemical stimulation in many subjects, short abrupt bursts of activity were frequently present at the transitions between inspiration and expiration. To determine the mechanical effect of the latter electromyographic findings, arytenoideus activity and fiber-optic images of the glottic aperture were simultaneously recorded in nine additional normal adult human subjects during progressive hyperoxic hypercapnia. The short abrupt bursts of arytenoideus activity were usually associated with a decrease in glottic aperture, although no change and an increase in glottic aperture were observed in individual subjects. The results suggest that the arytenoideus muscle may have an important role in the control of ventilation in normal human subjects.

Download Full-text

Voluntary hyperventilation changes recruitment order of parasternal intercostal motor units

Journal of Applied Physiology ◽

10.1152/jappl.1987.62.1.187 ◽

1987 ◽

Vol 62 (1) ◽

pp. 187-193 ◽

Cited By ~ 11

Author(s):

T. W. Watson ◽

W. A. Whitelaw

Keyword(s):

Human Subjects ◽

Motor Units ◽

Quiet Breathing ◽

Rib Cage ◽

Voluntary Hyperventilation ◽

Single Motor ◽

Intercostal Muscles ◽

Single Motor Units ◽

Normal Human ◽

Recruitment Order

The order of recruitment of single-motor units in parasternal intercostal muscles during inspiration was studied in normal human subjects during quiet breathing and voluntary hyperventilation. Electromyograms were recorded from the second and third intercostal spaces by means of bipolar fine wire electrodes. Flow at the mouth, volume, end-expired CO2, and rib cage and abdominal anterior-posterior diameters were monitored. Single-motor units were identified using criteria of amplitude and shape, and the time of first appearance of each unit in each inspiration was noted. Hyperventilation was performed with visual feedback of the display of rib cage and abdomen excursions, keeping the ratio of rib cage to abdominal expansion. Subjects were normocapnic in quiet breathing and developed hypocapnia during hyperventilation. Recruitment order was stable in quiet breathing, but in some cases was altered during voluntary hyperventilation. Some low threshold units that fired early in the breath in quiet breathing fired earlier at the beginning of a period of voluntary hyperventilation but progressively later in the breath as hyperventilation went on, whereas later firing units moved progressively toward the early part of inspiration. This suggests that different groups of motoneurons in the pool supplying parasternal intercostal muscles receive different patterns of synaptic input.

Download Full-text

Observations on a Relationship between Steroid Metabolism and the Concentration of Plasma Fibrinogen

Thrombosis and Haemostasis ◽

10.1055/s-0038-1654793 ◽

1963 ◽

Vol 10 (02) ◽

pp. 400-405 ◽

Cited By ~ 4

Author(s):

B. A Amundson ◽

L. O Pilgeram

Keyword(s):

Blood Coagulation ◽

Methyl Ether ◽

Broad Spectrum ◽

Human Subjects ◽

Plasma Fibrinogen ◽

Steroid Metabolism ◽

Specific Site ◽

Chain Reaction ◽

Normal Human ◽

A Chain

SummaryEnovid (5 mg norethynodrel and 0.075 mg ethynylestradiol-3-methyl ether) therapy in young normal human subjects causes an increase in plasma fibrinogen of 32.4% (P >C 0.001). Consideration of this effect together with other effects of Enovid on the activity of specific blood coagulatory factors suggests that the steroids are exerting their effect at a specific site of the blood coagulation and/or fibrinolytic system. The broad spectrum of changes which are induced by the steroids may be attributed to a combination of a chain reaction and feed-back control.

Download Full-text

Relationship Between Mepacrine-Labelled Dense Body Number, Platelet Capacity to Accumulate 14C-5-HT and Platelet Density in the Bernard-Soulier and Hermansky-Pudlak Syndromes

Thrombosis and Haemostasis ◽

10.1055/s-0038-1666908 ◽

1979 ◽

Vol 42 (02) ◽

pp. 694-704 ◽

Cited By ~ 31

Author(s):

F Rendu ◽

A T Nurden ◽

M Lebret ◽

J P Caen

Keyword(s):

Dense Body ◽

Human Subjects ◽

Human Platelets ◽

Dense Bodies ◽

Storage Organelle ◽

Hereditary Disorders ◽

Labelling Procedure ◽

Normal Human ◽

Hermansky Pudlak Syndrome ◽

Bernard Soulier Syndrome

SummaryWe have used the mepacrine-labelling procedure to measure the dense body (serotonin storage organelle) content of the platelets of 2 hereditary disorders where abnormalities in dense body number were suspected. The platelets were incubated with mepacrine and examined by fluorescence microscopy. A mean number of 5.4 ± 0.8 (SD) dense bodies per platelet was calculated from the data obtained using platelets isolated from 40 normal human subjects. In contrast the platelets of 2 patients with the Bernard-Soulier syndrome contained an average of 14 and 17 labelled granules. This increase was associated with a much greater capacity of the platelets to accumulate 14C-5-HT. The opposite result was obtained using the platelets from 2 patients with the Hermansky-Pudlak syndrome which contained few granules labelled by mepacrine and took up less 14C-5-HT than normal human platelets. Centrifugation of the patients’ platelets on discontinuous sucrose gradients showed that the platelets of the 2 Bemard-Soulier patients were much denser than normal whereas a high proportion of low density platelets was observed in the Hermansky-Pudlak syndrome. These results further define the platelet abnormalities in the two syndromes and suggest that dense body number may be one of the factors governing platelet density.

Download Full-text

ADRENERGIC CONTROL MECHANISM FOR ACTH SECRETION IN MAN

Acta Endocrinologica ◽

10.1530/acta.0.0740263 ◽

1973 ◽

Vol 74 (2) ◽

pp. 263-270 ◽

Cited By ~ 50

Author(s):

Yoshikatsu Nakai ◽

Hiroo Imura ◽

Teruya Yoshimi ◽

Shigeru Matsukura

Keyword(s):

Intravenous Infusion ◽

Human Subjects ◽

Blocking Agent ◽

Inhibitory Effect ◽

Plasma Acth ◽

Acth Secretion ◽

Glucose Levels ◽

Alpha Receptors ◽

Normal Human ◽

Adrenergic Blocking

ABSTRACT In order to determine if an adrenergic mechanism is involved in the secretion of corticotrophin (ACTH), the effect of adrenergic-blocking or -stimulating agent on plasma ACTH, cortisol and glucose levels was studied in normal human subjects. The intravenous infusion of methoxamine, an alpha adrenergic-stimulating agent, caused a rise in plasma ACTH and cortisol. This increase in plasma ACTH and cortisol was significantly inhibited by the simultaneous administration of phentolamine, an alpha adrenergic-blocking agent, in combination with methoxamine. The intravenous infusion of propranolol, a beta adrenergic-blocking agent, caused no significant change in plasma ACTH and cortisol, although it enhanced the plasma ACTH response to insulin-induced hypoglycaemia. On the other hand, alpha adrenergicblockade by intravenous infusion of phentolamine significantly suppressed the plasma ACTH response to insulin-induced hypoglycaemia. These studies suggest a stimulatory effect of alpha receptors and a possible inhibitory effect of beta receptors on ACTH secretion in man.

Download Full-text

Specialized systems for the processing of mnemonic information within the primate frontal cortex

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.1996.0130 ◽

1996 ◽

Vol 351 (1346) ◽

pp. 1455-1462 ◽

Cited By ~ 229

Keyword(s):

Frontal Cortex ◽

Specific Activity ◽

Human Subjects ◽

Long Term Memory ◽

Executive Processing ◽

Severe Impairment ◽

Normal Human ◽

Short And Long Term ◽

Cortical Association Areas

The lateral frontal cortex is involved in various aspects of executive processing within short- and long-term memory. It is argued that the different parts of the lateral frontal cortex make distinct contributions to memory that differ in terms of the level of executive processing that is carried out in interaction with posterior cortical systems. According to this hypothesis, the mid-dorsolateral frontal cortex (areas 46 and 9) is a specialized system for the monitoring and manipulation of information within working memory, whereas the mid-ventrolateral frontal cortex (areas 47/12 and 45) is involved in the active retrieval of information from the posterior cortical association areas. Data are presented which support this two-level hypothesis that posits two distinct levels of interaction of the lateral frontal cortex with posterior cortical association areas. Functional activation studies with normal human subjects have demonstrated specific activity within the mid-dorsolateral region of the frontal cortex during the performance of tasks requiring monitoring of self-generated and externally generated sequences of responses. In the monkey, lesions restricted to this region of the frontal cortex yield a severe impairment in performance of the above tasks, this impairment appearing against a background of normal performance on several basic mnemonic tasks. By contrast, a more severe impairment follows damage to the mid-ventrolateral frontal region and functional activation studies have demonstrated specific changes in activity in this region in relation to the active retrieval of information from memory.

Download Full-text

Study on the Postprandial Blood Glucose Suppression Effect ofD-Psicose in Borderline Diabetes and the Safety of Long-Term Ingestion by Normal Human Subjects

Bioscience Biotechnology and Biochemistry ◽

10.1271/bbb.90707 ◽

2010 ◽

Vol 74 (3) ◽

pp. 510-519 ◽

Cited By ~ 85

Author(s):

Noriko HAYASHI ◽

Tetsuo IIDA ◽

Takako YAMADA ◽

Kazuhiro OKUMA ◽

Isao TAKEHARA ◽

...

Keyword(s):

Blood Glucose ◽

Human Subjects ◽

Postprandial Blood Glucose ◽

Suppression Effect ◽

Normal Human ◽

Borderline Diabetes

Download Full-text

Effect of Age on Oxygen-Binding in Normal Human Subjects

Clinical Science ◽

10.1042/cs0510185 ◽

1976 ◽

Vol 51 (2) ◽

pp. 185-188

Author(s):

P. M. Tweeddale ◽

R. J. E. Leggett ◽

D. C. Flenley

Keyword(s):

Oxygen Saturation ◽

Oxygen Tension ◽

Inorganic Phosphate ◽

Human Subjects ◽

Oxygen Binding ◽

Corpuscular Haemoglobin ◽

Positive Correlation ◽

Normal Human ◽

Mean Corpuscular Haemoglobin ◽

Effect Of Age

1. Oxygen-binding, plasma and intra-erythrocytic pH, and haemoglobin, 2,3-diphosphoglycerate and inorganic phosphate concentrations were measured in sixty-two healthy non-smokers aged between 18 and 89 years. 2. P50 (oxygen tension at 50% oxygen saturation) expressed at plasma pH 7·40 and Pco2 5·33 kPa showed a positive correlation with age. 3. This correlation of P50 with age was closer when P50 was expressed at a constant intra-erythrocytic pH 7·20. On average P50 at intra-erythrocytic pH 7·20 increased from 3·59 kPa at 20 years to 3·96 kPa at 90 years of age. 4. 2,3-Diphosphoglycerate, inorganic phosphate, haemoglobin and mean corpuscular haemoglobin concentrations did not correlate with P50 or with age.

Download Full-text