PubMed HealthSearch

Biomedical subjects

K Shima

Publications and source records attributed to K Shima.

At least 37 records · Page 2Linked to original sources

[Effects of diazepam on evoked potential recorded from basal medial amygdaloid nucleus, lateral hypothalamus and midbrain reticular formation (author's transl)].

The evoked potential in the lateral hypothalamus (LH) recorded by stimulation of basal medial amygdaloid nucleus (Abm) showed a triphasic pattern and diazepam (2 mg/kg, i. p.) decreased the late component. The evoked potential in the midbrain reticular formation (MRF) recorded by stimulation of Abm showed a fast component with a relatively short latency followed by a biphasic late component and diazepam decreased the late component. Though the evoked potential in the Abm recorded by stimulation of LH showed a triphasic pattern, diazepam had no influence on the amplitude. Diazepam increased markedly the amplitude of evoked potential in the MRF recorded by stimulation of LH. Diazepam was ineffective on the evoked potential in the Abm recorded by stimulation of MRF. Diazepam decreased markedly the late component of evoked potential in the LH recorded by stimulation of MRF. These results suggest that the depression of emotional behavior by diazepam may be particularly related to the fact that the evoked potential in the LH recorded by stimulation of Abm was decreased by diazepam.

Amygdala

Failure of exogenous insulin to inhibit insulin secretion in man.

In order to explore whether or not the negative feedback mechanism of insulin per se on insulin secretion exists in man, changes in plasma C-peptide immunoreactivity (CPR), as an index of pancreatic B cells secretory function, were studied in 6 nonobese healthy volunteers in the presence of high circulating levels of exogenous insulin. 10% glucose was infused concurrently so as to maintain blood sugar at the basal level. The insulin-glucose infusion was maintained for 120 minutes, achieving mean plasma levels of 140-180 mu1/ml. After this period, the insulin infusion was continued at the same rate for an additional 10 minutes while the glucose was omitted. Despite the elevated level of circulating insulin, no significant change in plasma CPR concentration was observed so long as the blood sugar was maintained at the basal levels. Following cessation of the glucose infusion, the plasma CPR levels declined with a decrease in blood sugar level. Under the conditions of the present study, no inhibitory effect of exogenous insulin on the secretory function of the B cells was noticed.

Adult

[Effects of morphine on the single unit activity of nucleus dorsal raphe].

Effects of morphine were studied in 36 gallamine triethiodide immobilized adult cats under light N2O anesthesia. Single units were recorded from the nucleus dorsal raphe using a stainless steel microelectrode. Dorsal raphe neurons were divided into two types; one was a clock-like (CL) neuron which was typically slow in rate, rhythmic and stable throughout recording time, and the other was a non-clock like (NCL) neuron which was relatively irregular in pattern as compared with CL neuron. Out of 36 neurons recorded in this experiment, 13 were CL neurons and 23 were NCL neurons. Mean discharge rates (spikes per sec) of CL neuron and NCL neuron were 2.84 (range of 2.01 approximately 3.68) and 4.11 (range of 0.10 approximately 35.09), respectively. None of the 13 CL neurons responded to the nociceptive (pinch and/or brdaykinin) and non-nociceptive (hair bending and/or tapping) stimuli. On the contrary, out of 23 NCL neurons, 13 responded to both nociceptive and non-nociceptive stimuli, 4 were responsive to only non-nociceptive stimuli and 6 were not responsive to these stimuli. Receptive fields of NCL neurons were wide with various somatic modalities. The latency for bradykinin (3 microgram) was 6.46 +/- 0.77 sec. Effects of morphine were examined in 6 CL neurons and 12 NCL neurons. After morphine, no nociceptive neuron responded to nociceptive stimuli, although there was no appreciable change in the responsiveness to non-nociceptive stimuli. Firing frequency and pattern of all CL neurons were unaffected by morphine. Out of 12 NCL neurons, 7 were unaffected in firing frequency and 5 were decreased after morphine.

Action Potentials

[Effects of morphine on evoked potential recorded from pain-afferent pathways (author's transl)].

Effects of morphine (1 mg/kg i.v.) were examined on evoked potential of somatosensory afferent pathways elicited by tooth pulp stimulation in cats. Results were as follows: In central gray (CG) of the midbrain which has a triphasic evoked potential with a short latency, morphine decreased the amplitude. In nucl. lateralis posterior(LP) and nucl. medialis dorsalis(MD) of the thalamus, association relay nuclei, which have a late component followed by a fast component with a relatively short latency, morphine decreased the amplitude of the late component but not that of fast component of the evoked potential. In nucl. centralis lateralis(CL) of the thalamus, intralaminar nuclei, and pre-central association area(PCA) of the cortex, which have monophasic and triphasic evoked potentials with a long latency, respectively, morphine markedly decreased the amplitude of both evoked potentials. In nucl. ventralis posteromedialis(VPM) and somatic sensory area I (SI), lemniscal system, which has biphasic and mutiphasic evoked potentials with a short latency, respectively, morphine had no effect on these evoked potentials. As these depressant effects of morphine on evoked potentials were antagonized by naloxone (0.2mg/kg i.v.), a specific morphine action is suggested.

Afferent Pathways

[Effects of capsaicin on spontaneous unit discharges in medial thalamic single neurons of cats (author's transl)].

The effect of capsaicin was studied in gallamine triethiodide immobilized adult cats. Single neurons were recorded from the medial thalamus with a stainless steel microelectrode. Out of 21 neurons recorded in this experiment, 10 were responsive to both nociceptive (pinch) and non-nociceptive (hair bending and/or tapping) stimuli. Six neurons were responsive to only non-nociceptive stimuli and 5 were not responsive to these stimuli. Out of 10 neurons responding to both nociceptive and non-nociceptive stimuli, 9 were responsive to both bradykinin (3 microgram) and capsaicin (3 microgram). Out of 6 neurons responding to only non-nociceptive stimuli, 5 were not responsive to either bradykinin and capsaicin. All neurons responding to bradykinin were also responsive to capsaicin. The latency for bradykinin and capsaicin was 7.64 +/- 1.12 sec and 0.97 +/- 0.07 sec, respectively. The increased in firing frequency produced by capsaicin was depressed by morphine. However, these depressant effects of morphine on single unit activity were antagonized by naloxone.

Action Potentials

Insulin releasing activity of gastrointestinal glucagon-like immunoreactive materials in perfused rat pancreas.

Insulin-releasing activity of porcine gastrointestinal glucagon-like immunoreactive materials purified by affinity chromatography was examined in the perfused rat pancreas. When glucose concentration of the perfusate was raised from 60 to 100 mg/dl, augmented insulin release was observed. The mean incremental area of immunoreactive insulin (sigma delta IRI) during the first 10 min thus observed was 19.07 +/- 3.76 ng/10 min. Pancreatic glucagon and the extract from the gastric fundus showed the enhancement of insulin release in this system when they were added to the perfusate at the rate of 100 ng/min for 5 min; delta IRI were 41.92 +/- 8.47 and 71.70 +/- 18.09 ng/10 min, respectively, which were significantly higher than that of 100 mg/dl of glucose alone. However, no significant difference in the insulinogenic activity was noticed between the extracts from the small intestine and the control. These results suggest that the extract from the gastric fundus has insulinogenic activity similar to that of pancreatic glucagon.

Animals

Mechanism of hypoglycemia observed in a patient with insulin autoimmune syndrome.

A 21-year-old female patient complaining of frequent hypoglycemic attacks in the presence of a large amount of circulating insulin-binding antibodies without previous known immunization is described. In order to clarify the possible mechanism of the hypoglycemic attacks occurring in this new syndrome, changes in plasma glucose, plasma total and free immunoreactive insulin (IRI), and C peptide immunoreactivity (CPR) levels were investigated in the patient before, during, and after a three-hour glucose infusion. The character of her antibodies were also examined. An abrupt discontinuation of the glucose infusion caused a sharp decline in the plasma glucose level, reaching a nadir of 30 mg./100 nk, at 270 minutes; then she became unconscious. A huge amount of total IRI of 2,834 micron U./ml. was registered at 180 minutes, while the peak value of free IRI of 208 micronU./ml. was observed 45 minutes after the cessation of the glucose infusion. Plasma CPR was increased from high basal level, 19.6 ng./ml., to the maximum level of 29.2 ng./ml. The maximum insulin-binding capacity of IgG in the patient's serum was 6.25 mU./ml. The antibody-combining site was homogeneous, showing one high-affinity site (K: 1.1 X 10(9)M-1). Neither the prolonged fasting nor the administration of tolbutamide induced the hypoglycemic attack in the patient. The hypoglycemia may be explained by an unduly excessive amount of insulin liberated from a large pool of bound insulin irrespective of blood sugar level. The cause of the antibody production is also discussed.

Adult

[Analgesic effect of pentazocine and its action on nociceptive afferent pathway].

Nociceptive stimulus was applied to the skin of adult cats by pinching with a serrated forceps or by radiant heat with Pain meter. This stimulation caused motor or emotional responses such as movements of the head and trunk, vocalization, escape and attack. After the administration of pentazocine, these responses disappeared and the animals behaved normally. Analgesic action appeared approximately 15 min after the administration and lasted more than 90 min. Effects of pentazocine on pain-afferent pathways were studied and the evoked potential was recorded by tibial nerve stimulation. Though pentazocine did not influence the evoked potential recorded from somatic sensory area I and mesencephalic central gray, the evoked potential in pre-central association area, nucleus centralis lateralis, nucleus suprageniculatus-limitans and reticularis pontis caudalis was reduced by pentazocine.

Afferent Pathways

Diagnostic routes in cases with single involvement in eyes suspected of sarcoidosis.

The ocular involvement of sarcoidosis is particularly important in Japan, because 1. the frequency of the eye involvement is as high as 20 to 40%, higher than in other countries- 2. the presence of this involvement proved to be an influential factor relating to the whole sarcoidosis lesions of a patient, and 3. the patients with this involvement will become blind unless adequately treated. In diagnostic routines of ocular sarcoidosis, chest X-rays will give the most useful information of the disease. If the chest X-ray findings are normal, it is not easy to make a diagnosis of a case whose ocular findings are very suspicious of sarcoidosis. This paper will give several case experiences in which we could successfully make a diagnosis, using mediastinoscopical biopsies though the X-rays had no findings.

Adolescent

Long-term follow-up in sarcoidosis in Japan.

The clinical course of 775 sarcoidosis cases in Japan collected by the Japan Sarcoidosis Committee was followed up in the 6th month, 1st, 2nd, 3rd, 4th-6th, 7th-9th and 10th year and over after the first discovery. The means follow-up period was 5.5 years. The accumulated rates of disappearance of BHL, lung, eye, and whole sarcoidosis lesions calculated by life-table method were 63%, 56%, 59% and 48% respectively at the 1st year, 75% 67%, 71% and 59% respectively at the 2nd year, 79%, 71%, 76% and 64% respectively at the 3rd year, 82%, 74%, 81% and 67% respectively at the 4th-6th year. Judging from the accumulated rates mentioned above, the speakers defined the course of the disease as "good" when the whole sarcoidosis lesions cleared within 2 years. It was revealed that out of 25 factors examined, factors such as "age under 29", "no eye lesions" and "without complaints" at the time of first discovery, were significantly useful for pre-dieting the "good" results. The disappearance of BHL within 6 months was one of the most important indices predicting the "good" outcome of sarcoidosis.

Adolescent

[Glucagonoma].

Explore the source record for details and available documents.

Adult