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Biomedical subjects

N Murakami

Publications and source records attributed to N Murakami.

At least 523 records · Page 29Linked to original sources
PubMed1986

Dehydration enhances endotoxin fever by increased production of endogenous pyrogen.

The febrile responses in rats to an intravenous injection of the bacterial endotoxin Salmonella typhosa were investigated under normally hydrated and dehydrated conditions. When endotoxin was injected intravenously into the dehydrated rats, a biphasic-patterned fever resulted, whereas in normal rats an intravenous injection of endotoxin did not induce fever. No significant differences in febrile responses to the intravenous endogenous pyrogen (EP), prostaglandin E2, and intracerebroventricular prostaglandin E2 between normal and dehydrated rats were observed. When the blood plasma obtained from rats with endotoxin-induced fever under dehydrated conditions was transferred to the normal rats, a significant rise in the body temperature was induced. The effect of hydration by an administration of the hypotonic solution after dehydration was examined in endotoxin-induced fever and in changes of the basic blood parameters. It is concluded that febrile responses to endotoxin during dehydrated condition are caused by an increased production of EP. The migration of leukocytes from circulation to any other tissue will be an important factor in producing EP under dehydrated conditions. Furthermore, under dehydrated condition, EP may be produced by numerous macrophages in tissues in vivo, where many kinds of leukocytes migrate and exchange signals with each other in developing an immune response.

Animals↗
PubMed1986

Fever in rats during normal and dehydrated conditions.

The effect of endogenous pyrogen (EP, from rabbit) and endotoxin (Salmonella typhosa) on rectal temperature (Tre) was investigated in normal and dehydrated rats of both sexes. Intraperitoneal injection of either EP or endotoxin did not affect body temperature. In addition, no changes in Tre were observed when endotoxin was injected intravenously in normally hydrated male rats, but significant falls in Tre occurred in normal female rats. However, intravenous injection of EP produced fever in both sexes, but females generally showed smaller responses. A second intravenous injection of endotoxin, given 3 days after the first injection, always produced fever in normally hydrated rats. The pattern of this febrile response was monophasic. In contrast to the response in normal rats, intravenous endotoxin produced significant fevers with a biphasic pattern in dehydrated rats of either sex, but the febrile responses of male rats were greater than those of female rats. On the other hand, there were no significant differences between febrile responses to intravenous EP exhibited by normal and dehydrated animals. These results show that rats of both sexes possess physiological mechanisms capable of producing a fever following intravenous injections of EP.

Animals↗
PubMed1986

Effect of constant light on the circadian rhythm in locomotor activity in intact or eyelids-removed rats.

According to the Aschoff's role, exposure to continuous light (LL) results in the elongation of the free-running period of the rat circadian rhythm. However, the LL may not always mean the constant intensity of the light for the suprachiasmatic nucleus, since the rat may regulate the contrast of the illumination by their eyelids which are closed during the sleep phase. In this study, the surgical removal of the eyelids under the LL caused arrhythmicity of the locomotor activity in 7 of 10 rats. The remaining 3 rats maintained the free-running rhythm after the removal of the eyelids. These results suggest that constant light may affect the free-running rhythm of the rat with or without eyelids in the different manner.

Animals↗
PubMed1986

Effects of continuous supply of light or carbachol to the SCN on the rat free-running rhythm.

Exposure to continuous light (LL) results in elongation of the free-running period of the rat circadian rhythm. However, the LL may not always mean constant intensity of light for the suprachiasmatic nucleus (SCN), since rats may regulate contrast of illumination by their eyelids which are closed during sleep phase. The removal of eyelids caused shortening of the free-running period or arrhythmicity under LL. In addition, implantation of carbachol--acetylcholine agonist--near the SCN also resulted in similar effects.

Animals↗
PubMed1986

[A histochemical study on postnatal growth of the soleus muscles of male and female mice].

Postnatal changes in histochemical properties of the soleus muscles were examined in male and female mice aged 5 to 40 weeks. The fiber type composition did not significantly differ between sexes 5 weeks after birth. In males the percentage of type I fibers increased from 5 to 22 weeks of age but did not change thereafter. In females the percentage of type I fibers increased from 5 to 40 weeks of age. As a result, females had significantly higher percentage of type I fibers than males 30 and 40 weeks after birth. The smaller increase in the percentage of type I fibers during postnatal growth in males is suggested to be attributable to the higher testosterone level. In males the cross-sectional area of both type I and type II fibers increased with age. In females, however, the cross-sectional area of type II fibers increased with age whereas that of type I fibers increased from 5 to 10 weeks of age but thereafter decreased gradually. The ratio of mean fiber cross-sectional area of type I fibers to that of type II fibers decreased slightly from 5 to 10 weeks of age but did not change thereafter in males. In females the ratio increased from 5 to 10 weeks but thereafter decreased gradually. The ratio was significantly higher in females than in males in all age groups. The percentage area occupied by type I fibers increased with age in both sexes. The increase was greater in females than in males, however. Furthermore, females had significantly higher value than males in all age groups. No significant age difference and sex difference were observed in the total number of muscle fibers.

Animals↗
PubMed1986

Prognosis of minute carcinoma of thyroid. Follow-up study of 49 patients.

Forty-nine patients with minute carcinoma of thyroid gland (clinically silent carcinoma less than 10 mm in diameter) underwent partial thyroidectomy and regional lymph node dissection. Nodal metastasis was found in 33 patients (67%). Histologically, no difference in the incidence of nodal metastasis was found between sclerosing carcinoma and nonsclerosing carcinoma. During the period of follow-up (from 3 to 18 years), neither recurrence of the carcinoma nor death was observed in 16 patients without nodal metastasis and 24 patients who had less than 4 metastatically involved nodes. In these 24 patients, most of the metastatic deposits were less than 5 mm in diameter and even the largest one did not exceed 16 mm. Recurrence without death was found in 2 of 4 patients who had many metastatically involved nodes, more than 8, or at least one large metastatic deposit measuring larger than 16 mm in diameter (moderately involved group), whereas recurrence followed by death occurred in 3 of 5 who had many involved nodes and at least one large deposit (extensively involved group). In both moderately and extensively involved groups, recurrence and death occurred in elder patients. The present study suggested that the prognosis of minute carcinoma depends on the degree of nodal involvement and age of the patient.

Adult↗
PubMed1985

Two chymotrypsin-susceptible sites of myosin rod from chicken gizzard.

The rod prepared from chicken gizzard myosin has been found to have two sites sensitive to limited digestion with chymotrypsin; these sites were located at a subfragment 2/light meromyosin junction (site 1), and at a site 10 kDa remote from either C-terminal or N-terminal of light meromyosin (site 2). The site 1 was more sensitive to the digestion than the site 2. The cleavage at site 2 of the light meromyosin yielded a 74-kDa fragment that was soluble in a low ionic strength solution, contrary to the insolubility of the parent light meromyosin in the same solution. Studies on the effects of MgCl2, ATP and pH on the susceptibilities of these sites to chymotrypsin have given following results. (a) Millimolar concentrations of MgCl2 protected site 1 and site 2 from the chymotryptic cleavage. (b) The cleavage at site 1 of myosin rod in the low salt solution free of Mg2+ at pH 7.0 and pH 8.5, was not affected by the presence of 5 mM ATP. However, MgCl2-induced protection of site 1 was relieved by addition of ATP. On the other hand, the cleavage at site 2 was stimulated by addition of ATP, irrespective of the presence or absence of MgCl2. (c) The alkaline condition of pH 8.5 was more favorable for the chymotryptic cleavages at both site 1 and site 2 than the neutral condition of pH 7.0. These results suggest that myosin rod contains two flexible regions, the structures of which are influenced by such an ambient factor as MgCl2, ATP or pH.

Adenosine Triphosphate↗
PubMed1985

Effects of duration and intensity of illumination on several parameters of the chick eye.

Effects of duration and intensity of illumination on eye weight, eye diameter, corneal diameter and anterior chamber depth were investigated in Warren chicks. Increase in eye weight was observed in continuous light, LD 22:2 and continuous darkness. Shallow anterior chamber and small corneal diameter were observed in continuous light and LD 22:2, but not in continuous darkness. Continuous bright light (5000 lux) did not induce an increase in the eye weight but instead induced severe lesions in the anterior segment of the eye. Injection of corticosterone (500 micrograms) induced a significant reduction in the eye weight.

Adrenal Glands↗
PubMed1985

DCCD-sensitive, Na+-dependent H+-influx process coupled to membrane potential formation in membrane vesicles of Halobacterium halobium.

The effects of N,N'-dicyclohexylcarbodiimide (DCCD) on light-induced H+-transport and transmembrane electric potential (delta phi) formation were studied in the membrane vesicles of Halobacterium halobium R1M1. In accordance with our previous finding of the existence of two DCCD-binding components in vesicle membrane using 14C-DCCD (Konishi & Murakami FEBS Lett. 169, 283-286 (1984)), DCCD inhibited the H+-influx process biphasically; that is, the H+-influx process which is electrically silent was initially inhibited at concentrations below 30 nmol of DCCD/mg vesicle protein, while another H+-influx process which is coupled to delta phi formation was secondarily inhibited above this concentration of DCCD. The latter H+-influx process was highly dependent on the Na+ concentration. The extents of Na+-dependent recovery of delta phi formation and H+-influx were quantitatively correlated. From these results, it was concluded that the second DCCD-sensitive H+-influx process which is coupled to delta phi formation is due to the hypothetical Na+/H+-antiporter postulated by Lanyi and MacDonald (Biochemistry 15, 4608-4614 (1976)). It was also found that Li+ can be substituted for Na+ in this system, as is the case with Na+/H+-antiporters found in other organisms.

Carrier Proteins↗
PubMed1985

Complex partial seizures in childhood.

A clinical and electroencephalographic study was undertaken on 215 children with complex partial seizures as selected on the basis of the International Classification of Epileptic Seizures (1981). Complex partial seizures were noted in 7.8% of the epileptic children. The ictal symptoms of complex partial seizures closely resembled those of psychomotor triad described by Lennox. Interictal EEG revealed seizure discharges from the temporal or frontal focus in 57.2%. There existed a group with automatism as a main symptom having both diffuse slow spike-waves and focal temporal spikes. This type should be interpreted to be one of secondary generalized epilepsies and be a variant of the Lennox syndrome.

Adolescent↗
PubMed1985

Minute carcinoma of the thyroid and its development to advanced carcinoma.

The relationship between the size of carcinomas and their histological characteristics such as encapsulation and sclerosis was studied using 157 cases of thyroid minute carcinomas with diameters less than 10 mm. When the diameter of the tumor was less than 1 mm, encapsulated carcinomas were not found, but they were presented in a group with a larger diameter. Sclerosing carcinomas were more frequently distributed in the group with a diameter less than 5 mm. With increasing tumor size, the carcinomas were reduced markedly in number and only two cases of sclerosing carcinoma were observed with a diameter more than 8 mm. It was concluded that thyroid minute carcinomas arise as nonencapsulated carcinoma, either sclerosing or non-sclerosing, followed by encapsulation at a later time and that some of the non-sclerosing carcinomas become apparent clinically, whereas most of the sclerosing carcinomas remain clinically silent throughout the entire life of the host.

Adenocarcinoma↗
PubMed1985

An immuno-electron microscopic study on intracellular localization of thyroglobulin (TG) in the thyroid gland in Grave's disease.

Intracellular localization of thyroglobulin (TG) using a pre-embedding diffusion technique and an indirect localization sequence has been made in human thyroid obtained from 20 patients with treated Grave's disease. Both antibodies, anti-human TG-rabbit IgG F(ab')2 and anti-rabbit IgG F(ab')2-goat IgG F(ab')2 fragments easily penetrated the cytoplasm of follicular cells which were dissociated by RPMI-1640 solution containing collagenase, dispase, and deoxyribonuclease. With light microscopic observation of semithin sections positive immuno-reaction for TG was demonstrated as fine granular deposits in the cytoplasm of the dissociated cells. In electron microscopic studies, intracellular antigen was well circumscribed within certain cell organelles in all cases with the positive immuno-reaction for TG being observed in perinuclear space, rough endoplasmic reticulum, Golgi complexes, secretory granules, and reabsorbed colloid droplets. Content of positive immuno-reaction product differed somewhat from one case to another and from one follicle to another even in the same case. There was no immunoreaction product in nuclei, mitochondria, lysosomes, and lipofuscin-like granules.

Cytoplasm↗