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Biomedical subjects

A Ito

Publications and source records attributed to A Ito.

At least 1,009 records · Page 56Linked to original sources
PubMed1978

Variability of the respiratory phase, respiratory pause, and numbers and durations of respirations during periodic breathing.

The analysis of cycles of periodic breathing (Cheyne-Stokes rhythms) in 35 patients showed wide variability of mean values of respiratory phases. The respiratory pauses are usually shorter and the scatter of the mean values is smaller. Only in four cases were respiratory pauses longer than respiratory phases. The duration of the respiratory phase becomes extended through the increase of number of single respirations. The latter also shows a very small scatter. The respiratory rate in 32 out of 35 patients was higher than normal and is to be considered as tachypnoea.

Brain Diseases↗
PubMed1978

The definition of "Cheyne-Stokes rhythms".

The review of the literature on Cheyne-Stokes respiratory periods reveals enormous variation of the opinions expressed. The original description concerned periodicity characterized by rhythmic changes of respiratory phases and respiratory pauses in a relation of 60 : 15 seconds. In the respiratory phase there were 30 respirations of increasing depths and frequency at the beginning of the phase and decreasing depths and frequency at the end of the phase. Literature data about Cheyne-Stokes respiration comprise a multiplicity of all rhythymic forms. The duration of respiratory cycles varies between 12 and 130 seconds. The relation of the respiratory phase and respiratory pause between 6 : 4 or 75 : 70 seconds, and the number of breaths between 3 and 30 during one respiratory phase. Cheyne-Stokes periods were observed in health subjects as well as in patients with neurological, neurosurgical, cardiac, pulmonary and paediatric diseases. Cheyne-Stokes periods were explained as sequel of prolongation of circulation time between pulmonary alveoli and respiratory centre, through increased sensitivity of the respiratory centre to CO2, diminished sensitivity of the respiratory centre to CO2 and O2-deficit, local blood flow disturbances, section of pathways in the brain stem with disinhibition of basic rhythms, brain immaturity, alterations of consciousness, and respiratory obstructions. Rhythmic changes of the heart beat, of excitability of the heart muscle, of blood pressure, of EEG and of neurological and mental signs were observed. In spite of numerous observations detailed analysis of the respiratory cycle was performed in only a few cases. Major studies are lacking.

Animals↗
PubMed1978

Duration of the respiratory periods of uniform respiratory rhythms in 35 patients with neurosurgical diseases.

Analysis of uniform respiratory rhythms in 35 neurosurgical patients showed that the mean duration of respiratory periods was between 8.60 and 71.51 seconds. The scatter around the mean value increases with the increase of the duration of the respiratory period. For an individual patient there is a one-peak distribution of the duration of respiratory periods. The duration of respiratory periods increases with age. There is a group of patients in whom the respiratory periods last over 40 seconds. This group is difficult to classify. There are no correlations between the acid-base values, blood gas values, and the duration of respiratory periods. Analysis of 10 autopsy cases showed lesions in the brain stem without any particular prevalence.

Alkalosis, Respiratory↗
PubMed1978

The analysis of the intracranial pressure by the concept of the driving pressure from the vascular system.

In order to understand the pathogenesis of intracranial hypertension, the intracranial pressure (ICP) has usually been studied with the concept of volumetric pressure. In other words, the ICP is held to derive from the volume of the intracranial elements (e.g., brain, blood and cerebrospinal fluid). In this paper, the authors propose a new concept of the so-called driving pressure and apply it to both clinical and experimental studies. The driving pressure (DP) consists of the combined pressure continuously exerted on the ICP by the arterial pressure (ADP) and venous pressure (VP) systems.

Adolescent↗
PubMed1978

Endoplasmic reticulum marker enzymes in Golgi fractions--what does this mean?

NADPH cytochrome c (cyt c) reductase and glucose-6-phosphatase, two enzymes thought to be restricted to the endoplasmic reticulum (ER) and widely used as ER markers, are present in isolated Golgi fractions assayed immediately after their isolation. Both enzymes are rapidly inactivated in fractions stored at 0 degrees C in 0.25 M sucrose, conditions which do not affect the activity of other enzymes in the same preparation. The inactivation process was shown to be dependent on time and protein concentration and could be prevented by EDTA and catalase. Morphological evidence shows that extensive membrane damage occurs parallel with the inactivation. Taken together with the immunological data in the companion paper, the findings indicate that the enzymes NADPH cyt c reductase and probably glucose-6-phosphate are indigenous components of Golgi membranes.

Catalase↗
PubMed1978

Presence of NADPH-cytochrome P-450 reductase in rat liver Golgi membranes. Evidence obtained by immunoadsorption method.

Light Golgi fractions (GF(1+2)) prepared from rat liver homogenates by a modification of the Ehrenreich et al. procedure (J. Cell Biol. 59:45) had significant NADPH-cytochrome P(450) reductase (NADPH-cyt c reductase) activity if assayed immediately after their isolation. An antibody raised in rabbits against purified microsomal and Golgi fractions. To find out whether this activity is located in bona fide Golgi elements or in contaminating microsomal vesicles, we used the following 3-step immunoadsorption procedure: (a) antirabbit IgG (raised in goats) was conjugated to small (2-5 mum) polycrylamide (PA) beads; (b) rabbit anti NADPH-cyt c reductase was immunoadsorbed to the antibody-coated beads; and (c) GF(1+2) was reacted with the beads carrying the two successive layers of antibodies. The beads were then recovered by centrifugation, and were washed, fixed, embedded in agarose, and processed for transmission electromicroscopy. Antireductase- coated beads absorbed 60 percent of the NADPH-cyt c reductase (and comparable fractions of NADH-cyt c reductase and glucose-6-phosphatase) but only 20 percent of the galactosyltransferase activity of the input GF(1+2). Differential vesicle counts showed that approximately 72 percent of the immunoadsorbed vesicles were morphologically recognizable Golgi elements (vesicles with very low density lipoprotein [VLDL] clusters or Golgi cisternae); vesicles with single VLDL and smooth surfaced microsome-like vesicles were too few (approximately 25 percent) to account for the activity. It is concluded that NADPH-cytochrome P(450) reductase is a Golgi membrane enzyme of probably uneven distribution among the elements of the Golgi complex.

Animals↗
PubMed1978

Effect of zinc and calcium ions on the production of alpha-toxin and proteases by Clostridium perfringens.

Clostridium perfringens produced at least three distinct proteases in a synthetic medium containing calcium. Two of them, thiol and ethylenediaminetetraacetic acid disodium salt-sensitive proteases, appeared at an early stage of growth, but the other one, perhaps being identical to the one produced in a calcium-deficient medium, appeared at a late stage. The production of these proteases depended on Ca2+ but not on Zn2+ in the medium. Alpha-toxin, perhaps being a zinc-containing metalloenzyme, was rather resistant to the proteases, but toxin, produced in a zinc-deficient medium or deprived of zinc with ethylenediaminetetraacetic acid disodium salt, was very sensitive. By adding Zn2+, the toxin lacking zinc may have been converted to the zinc-containing metalloprotein that is resistant to proteases. This may explain why alpha-toxin activity increased progressively in a zinc-containing medium in spite of simultaneous production of potent proteases and why it disappeared rapidly in a zinc-deficient medium.

Bacterial Toxins↗
PubMed1978

Cellular injury of adrenocorticotropic pituitary tumor (AtT-20) by corticosteroid in mice.

A transplantable ACTH-secreting pituitary tumor (AtT-20) in mice was studied for its growth in relation to adrenocortical steroid. The latency of transplanted tumor in LAF-1 mice with 10(6) tumor cells was about 2 weeks in adrenalectomized and in intact mice. In the former, however, tumor size reached 1.5 cm in diameter within 1 month, while it remained about 0.5 cm in the latter. Macroscopic and microscopic observation revealed that the tumor grafted in intact mice showed massive necrosis, leaving minimum intact tumor cells among necrotic foci. In contrast, the tumor grafted in adrenalectomized mice was healthy, soft, and showed adenomatous structure. It is concluded that excess of adrenocortical steroid produced in the grafted AtT-20 was inhibitory for the growth of transplanted tumor and removal of the adrenal glands was good for growth and survival of transplanted tumor. For the assessment of direct effect of adrenal steroid on AtT-20 cells, incorporation of 3H-thymidine in cultured AtT-20 cells was examined in a medium supplemented with glucocorticoid hormone. The autoradiographic study indicated that the inhibition of 3H-thymidine uptake was demonstrated at 24 hr after incubation with steroid and labeled cells were barely detectable on 3rd and 5th day.

Adenoma↗