Biomedical subjects

M Kojima

Publications and source records attributed to M Kojima.

At least 865 records · Page 48Linked to original sources

PubMed1982

An electronmicroscopical study on peroxidase activity of rabbit monocytes, resident and exudate macrophages.

Changes of peroxidase (PO) activity in blood monocytes, untreated or stimulated peritoneal macrophages and subcutaneous exudate macrophages of rabbits were investigated with the glucose-oxidase method in the culture experiments of these cells after their in vitro or in vivo adherence to the surface of foreign bodies. 1) PO activity was demonstrated in the nuclear envelope (NE) and rough endoplasmic reticulum (rER) in 75% of the untreated peritoneal macrophages. 2) Blood monocytes, most of the stimulated peritoneal macrophages, and subcutaneous exudate macrophages showed no PO positivity. 3) In the in vitro culture of blood monocytes and stimulated peritoneal macrophages, there appeared from 2 hours cells showing PO positivity in NE and rER. 4) Although blood monocytes, stimulated peritoneal macrophages, and subcutaneous exudate macrophages after their in vivo surface adherence showed no PO positivity, it appeared in these cells when further cultured in vitro. From the fact that such a positive change of PO activity in these cultured cells is not only a transient phenomenon but also in vitro cultural one, we cannot subscribe to the view that blood monocyte is the precursor of resident macrophages.

Animals↗

PubMed1982

Effects of disopyramide on the maximum rate of rise of action potential (Vmax) in guinea-pig papillary muscles.

The correlation between the steady state and non-steady state depression of Vmax by 50 microM disopyramide was investigated in 2.7, 5.4 and 8.1 mM [K+]o using isolated guinea-pig papillary muscles. An elevation of [K+]o from 2.7 to 8.1 mM strengthened the depressant action of the drug on Vmax (steady state) at 1 to 5 Hz, but attenuated this action at 0.05 and 0.1 Hz. The Vmax-membrane potential (Vm) relationship (steady state) was examined at stimulation rates of 0.1 and 1 Hz by increasing [K+]o from 2.7 to 19 mM. The drug shifted the normalized Vmax-Vm curve at 1 Hz in a hyperpolarizing direction, but shifted the curve at 0.1 Hz upward at Vm between -90 and -65 mV without a shift along the Vm axis. The recovery process of Vmax (non-steady state) was examined by introducing premature stimuli or by interrupting the basic stimulus of 1 Hz for a certain period. The control recovery processes in three [K+]o were approximated by a triple exponential function (the earliest, intermediate and latest components). The drug slowed the intermediate component, but accelerated the latest one (the earliest component was situated within the refractory period) of [K+]o attenuated the depressant action of disopyramide on the Vmax at 0.05 and 0.1 Hz and accelerated the recovery process of Vmax at long diastolic intervals of more than 10 sec was quite unique.

Action Potentials↗

PubMed1982

Inhibitory effect of vitamin E on lipoperoxide formation in rat adrenal gland.

The tissue uptake of vitamin E administered to the rats was strikingly high in the adrenal glands, and microradioautographic studies showed that the vitamin was localized morphologically in the cells of fascicular and reticular zones of the adrenal cortex, where lipofuscin pigment appears with aging. On the other hand, it was confirmed that the TBA content in rat plasma and adrenal gland was elevated following whole-body 60Co irradiation as an aging model. It was also demonstrated that the TBA content in rat adrenal markedly increased in conditions of vitamin E deficiency with and without irradiation.

Adrenal Glands↗

PubMed1982

Immunohistochemical studies on the processes of serotonin neurons and their ramification in the central nervous system--with regard to the possibility of the existence of Golgi's rete nervosa diffusa.

Using various vertebrates from teleost to macacus, we studied, by the modified PAP method, the serotonin neurons that are distributed mainly in the raphe nuclei area, focussing on their process ramifications, and obtained the following results. 1. The shapes of serotonin neurons were varied. They were multipolar with many long, thick dendrites. In most of the neurons, more than two axons originated either from the stem of a dendrite or from its tip. 2. The axons contained spherical or spindle-shaped varicosities of varied sizes (diameter 0.5-6 micron). On a few occasions, they became large, Herring body-like droplets. 3. The axons were classified into four groups according to the shape and size of the varicosities they contained: stem fibers, A-fibers (tract fibers), B-fibers (branching fibers) and C-fibers (ground fibers). 4. The axon not only branched frequently, but formed a true network by way of frequent anastomosis at the level of B- and C-fibers. Serotonin fibers do not have endings that correspond to telodendrons, but conduct impulses through "en passant" type synapses. 5. A supraependymal plexus is formed over large areas of the ventricular system. This vast network is considered to be formed by the syncytial continuity of axonal reticulum of many serotonin neurons. 6. Serotonin neurons, and probably noradrenaline neurons as well, should be classified as a third type of neuron, which belong to neither the Deiters type nor the Golgi type neuron. Their characteristic feature is the long, reticular axons, and it is highly probable that this neuron system forms the "rete nervosa diffusa" proposed by GOLGI.

Animals↗

PubMed1982