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Biomedical subjects

S Enomoto

Publications and source records attributed to S Enomoto.

At least 199 records · Page 11Linked to original sources
PubMed1983

Identification and input-output properties of bulbar reticular neurons involved in the cerebral cortical control of trigeminal motoneurons in cats.

Neurons found in the medial bulbar reticular formation were activated by stimulation of the orbital gyrus and responded with antidromic spike potentials to selective stimulation of either the masseter or anterior digastric motoneuron pool in the trigeminal motor nucleus in cats anesthetized with alpha-chloralose. These two kinds of reticular neurons were assumed to be inhibitory neurons projecting to masseter motoneurons (IM neurons) and excitatory neurons projecting to anterior digastric motoneurons (ED neurons), involved in the effects of stimulation of the orbital gyrus on trigeminal motoneurons: inhibition of masseter motoneurons and excitation of anterior digastric motoneurons. Input-output properties of IM and ED neurons were studied intracellularly with the following results: (1) stimulation of the orbital gyrus evoked EPSPs in IM and ED neurons with mono- and polysynaptic latencies; and (2) stimulation of the lingual nerve evoked a spike potential in a few IM and ED neurons after a rather long latency, indicating that the pathways involved in the cortical control of trigeminal motoneurons via IM and ED neurons were basically separate from those responsible for the reflex control by the peripheral inputs. Intracellular injection of horseradish peroxidase revealed that both IM and ED neurons were small or medium in size and the former were smaller than the latter, while none of the large reticular neurons directly projected to the trigeminal motor nucleus. This suggests a possible functional differentiation among bulbar reticular neurons according to cell size.

Animals↗
PubMed1983

Basic and clinical evaluation of the measurement of bone resonant frequency.

A new computerized apparatus was constructed to measure the resonant frequency of human ulna in vivo with high sensitivity and reproducibility. Experimental studies using aluminum bar and dried human bone revealed the importance of the ulna being positioned parallel to the radius, approximately 90 degree flexion of the elbow joint, and minimal muscle activity in order to demonstrate maximum resonant frequency of ulna. Measurement of bone resonance in monkeys in vivo and after removal of the bone in vitro showed good agreement. Product of F (maximum resonant frequency in Hz) and L (ulnar length in cm), FL, indicating the speed of propagation of sound wave through the ulna, showed a significant positive correlation with bone mineral content/bone width (BM/BW) measured by Norland-Cameron apparatus and age-bound decline in both sexes. Patients with osteomalacia and primary hyperparathyroid bone disease tended to have higher FL values than expected from BM/BW. Two-dimensional display of FL and BM/BW thus appears to be useful in distinguishing osteoporosis from osteomalacia better than the use of BM/BW alone.

Adolescent↗
PubMed1983

Phase-linked variations in the amplitude of the digastric nerve jaw-opening reflex response during fictive mastication in the rabbit.

The diagastric nerve reflex response to stimulation of the upper lip was studied in urethan-anesthetized rabbits paralysed with pancuronium bromide. Rhythmic bursts of masticatory activity were evoked in the nerve by repetitive electrical stimulation of the motor cortex. The amplitude and latency of the reflex responses during fictive mastication were compared with preceding control values. When stimuli close to threshold were given, the largest and earliest responses occurred during the digastric burst. When intense stimuli were employed, the largest responses were out of phase with the burst, although the latency was still shortest when the motoneurons were rhythmically active. Since the pattern is essentially the same as that seen during normal mastication, we conclude that the cyclical modulation of reflex amplitude and latency is not the result of sensory feedback generated by the movements themselves but is instead governed by the central motor program.

Animals↗
PubMed1983

Comparison of airway responsiveness to exercise and histamine inhalation in asthmatics.

In order to investigate the differences between EIA positive and negative subjects, pulmonary function data at rest, atopic tendency and bronchial sensitivity and reactivity were compared. Pulmonary function data revealed no significant difference between two groups except closing volume which was higher in EIA positive patients (p less than 0.01) and also Rrs which was higher in EIA positive patients only in female (p less than 0.05). Incidence of positive skin tests and higher levels of IgE were more frequent in EIA positive, however, IgE was not significantly different. Relationship between % fall of FEV1 after exercise and bronchial sensitivity was examined, however, no correlation was found in two parameters. Bronchial reactivity was not different in two groups. This suggests that EIA positive patients cannot be distinguished from EIA negative by pulmonary function data at rest or by atopic tendency, and also that different mechanisms play a role to produce airway constriction following exercise and inhalation challenge.

Adolescent↗
PubMed1983

[Level of 5-FU in tumor tissues of the patients with head and neck malignant tumors after oral administration of UFT].

Levels of futraful (FT-207), 5-FU and Uracil in blood and tissue were measured on 11 cases of oral malignant tumors after administration of UFT. 1) After administration of UFT, the highest level of 5-FU was detected in tumor tissue followed by the normal lymph node, metastatic lymph node, and normal tissue which showed the lowest level. 2) Levels of 5-FU in serum was lower than in tumor, and T/S ratio of levels of 5-FU was 9,190. 3) There were significant regressions in levels of 5-FU and Uracil in normal lymph node (p less than 0.02). Coefficient of correlation was 0.469. 4) Comparisons of levels of 5-FU after administration of UFT and futraful were 1.89 in tumor, 1.72 in normal tissue, 1.80 in metastatic lymph node and 1.55 in normal lymph node. Level of 5-FU after administration of UFT was higher than that of futraful. 5) Higher level of 5-FU after administration of UFT in tumor tissue and lymph node were maintained for a longer period.

Antineoplastic Agents↗
PubMed1982

Bulbar reticular unit activity during food ingestion in the cat.

During food ingestion in cats, the activity of single bulbar reticular neurons showed rhythmical spike bursts during the active jaw opening phase of mastication. By utilizing spike-triggered averaging techniques, certain reticular cells were strongly suggested to be inhibitory neurons projecting to jaw closer motoneurons. We propose that these bulbar reticular neurons participate in the central generation of masticatory jaw movements by rhythmically inhibiting jaw closer motoneurons during mastication.

Animals↗
PubMed1982

Neural pathway involved in the excitation of motoneurones to jaw-opening muscles by stimulation of the orbital cerebral cortex in the cat.

The pathway and synaptic basis for the efferent discharge in the digastric nerve evoked by stimulation of the orbital cortex were studied in cats anesthetized with alpha-chloralose. Transection of the brain stem at the boundary between the pons and the medulla oblongata abolished discharge. Intracellular recording from anterior digastric motoneurones revealed that the orbital cortical stimulation evoked excitatory post-synaptic potentials with a latency that was longer by one synaptic delay than that of spike potentials evoked in medial bulbar reticular neurones making a direct excitatory projection to anterior digastric motoneurones. It was concluded that the excitatory effects was mediated by the medial bulbar reticular formation.

Animals↗