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Biomedical subjects

S Naruse

Publications and source records attributed to S Naruse.

At least 181 records · Page 10Linked to original sources
PubMed1990

Effects of atrial natriuretic peptide on brain oedema: the change of water, sodium, and potassium contents in the brain.

We examined the effect of atrial natriuretic peptide (ANP) administration on cerebral oedema in rats. Intravenous ANP infusion with total dose of 120 micrograms/kg and 100 micrograms/kg suppressed the elevation of water and Na contents in left middle cerebral artery (MCA) occluded and cold injured brain tissue, indicating that ANP has a suppressive effect on cerebral oedema. Similar ANP infusion at a low dose of 1 microgram/kg/h for 6 h also resulted in observation of the anti-oedematous effect in both models, with no observable occurrence of the known systemic effects of ANP on systolic blood pressure (SBP), heart rate (HR), hematocrit, or serum electrolyte ion (Na+, K+, Cl-) concentrations. The results thus suggest that the anti-oedematous effect of ANP is attributable to water and Na content control by ANP specific to the damaged tissue, possibly through inhibition of sodium transport. Taken together with a recent study in which it was shown that ANP might inhibit sodium transport in cerebral microvessel, our results suggest that ANP suppresses the development of brain oedema by inhibiting sodium transport and the coupled water influx.

Animals↗
PubMed1990

Effects of atrial natriuretic peptide on ischaemic brain oedema evaluated by the proton magnetic resonance method.

The effect of atrial natriuretic peptide (ANP) on cerebral oedema in rats was examined by magnetic resonance (MR). After occlusion of the left middle cerebral artery (MCA) to induce cerebral ischaemia, rats received continuous infusion of ANP for 24 h at a total dose of 120 micrograms/kg or 150 micrograms/kg. Proton relaxation times (T1 and T2) of excised oedematous tissue were measured in vitro and the area of the oedematous region was determined in vivo by the use of magnetic resonance imaging (MRI). The administration of ANP was found to decrease the lengthening of both T1 and T2 in the oedematous tissues and shown by MRI to decrease the area of the oedematous region, compared with group receiving saline. The topographic observations in vivo suggest that ANP suppress the development of the oedematous region.

Animals↗
PubMed1990

Further studies on protein secretion by rat submandibular glands in response to the beta 1- and alpha 1- adrenoceptor stimuli during postnatal development.

Developmental changes in salivary proteins secreted by the submandibular glands of male rats from 2 to 10 weeks of age in response to the beta 1- and alpha 1-adrenoceptor agonists, isoproterenol, methoxamine, dopamine, phenylephrine, epinephrine, norepinephrine and alpha-methylnoradrenaline, were studied by different electrophoreses and amino acid analysis. The electrophoretic patterns of proteins secreted by the glands in response to both stimuli changed dramatically every week up to 7 weeks of age, but thereafter appeared similar to those of adult submandibular salivary proteins. At 2 and 3 weeks of age, a few differences were found between the types of proteins secreted in response to two stimuli. These findings were also confirmed by an analysis of amino acid composition. The glandular levels of cGMP from 2 weeks and cAMP from 3 weeks of age were significantly elevated in response to methoxamine and isoproterenol. We conclude that functional maturation precedes morphological maturation in the submandibular glands of male rats.

Adrenergic Agonists↗
PubMed1990

125I-endothelin binds to fibroblasts beneath the epithelium of rat small intestine.

Rats were intravenously injected with synthetic 125I-endothelin, and then were fixed by intracardiac perfusion at 10 min, 30 min and 1 hr after the injection. Localization of 125I-endothelin was examined in the small intestine by light and electron microscopic radioautography. Through the time course examined, more than seventy percent of total silver grains were localized in the fibroblasts, especially beneath the basal lamina of epithelium of the intestinal villi. Silver grains were observed mostly on the thin processes, and also on the vacuoles. At 10 min, 80% of silver grains on the fibroblasts were located on the plasmalemma. By the chase, grains on the plasmalemma decreased, and silver grains in the cytoplasm increased gradually.

Animals↗
PubMed1989

Action of amino acids on stomach, pancreas, and gallbladder in dogs.

An intravenous infusion of a 3% solution of amino acids was given to 8 dogs, all with Heidenhain pouches and gastric fistulae. Four of these had duodenal cannulae opposite the pancreatic and 4 opposite the biliary ampulla. The usual basal 100 min spontaneous peaking of pancreatic juice volume and protein secretion was seen but peaks were abolished by the amino acid infusion and troughs were slightly elevated, but the total 90 min volume protein and bicarbonate outputs were not different from control. Gastric acid and pepsin secretions were augmented reaching a peak during the first hour with a subsequent decline. The 90 min acid and pepsin output was significantly higher than control. The gallbladder contracted during the first hour and remained thus until the infusion was terminated. This happened even when the duodenum was kept alkaline, but was abolished by ganglionic blockade. During intravenous amino acid infusion the patterns of gallbladder activity and pancreatic secretion resembled those of the post cibal rather than fasting state.

Amino Acids↗
PubMed1989

Magnetic resonance imaging of brain contusion.

In this study we investigated the time course of brain contusions using magnetic resonance imaging and compared the findings with those of a computed tomography scan. The lesions, which were demonstrated as homogeneous density areas on the computed tomography scan were demonstrated as different intensity areas in the magnetic resonance image. The intensity of the images varied according to the time at which the images were obtained. The findings indicated changes in the nature of the contusions including hematoma hemoglobin, perifocal edema extension, and so on. In conclusion, magnetic resonance imaging is important in the follow-up of chronological change as well as in original diagnosis of brain contusions.

Adolescent↗
PubMed1989

A comparative study of gastric secretory stimulants in conscious dogs.

1. In conscious dogs with gastric fistulae, Heidenhain pouches and Thomas duodenal fistulae, pentagastrin was found to be a more potent peak acid and pepsin stimulant in both innervated stomach and vagally denervated pouch than methacholine chloride. 2. Slopes of curves relating response to the logs of molar doses of pentagastrin and methacholine, at peak secretion, did not differ significantly. The maximal pentagastrin stimulated secretion from the pouch was smaller than that for methacholine; from the fistula they did not differ. 3. Ganglionic blockade depressed methacholine stimulated peak acid secretion, but did not affect pentagastrin stimulated acid secretion. Dose-response curves for methacholine-induced acid and pepsin secretion at the perigee did not differ from those obtained with ganglionic blockade. 4. Ganglionic blockade depressed pepsin secretion from the fistula whether stimulated with pentagastrin or methacholine. Pouch pepsin secretion was small and no difference between curves was seen.

Animals↗
PubMed1989

Isoprenaline and the pancreas in dogs.

1. In conscious dogs basal pancreatic secretion per 100 min was significantly reduced by 0.75 microgram kg-1h-1 of isoprenaline. The expected spontaneous peaking was seen only after stopping the drug. 2. Following propranolol, the 100-min pancreatic secretion was less than control but greater than secretion after isoprenaline. The interpeak interval was increased, and the perigee levels (interpeak) were higher than in the controls. Peak protein secretion was unaltered but volume was reduced. 3. Guanethidine did not abolish periodicity but it prolonged the interpeak interval. Protein peaks and 100-min totals were lower than control and volume perigees higher. 4. It is concluded that beta-adrenoreceptor stimulation inhibits pancreatic secretion. Adrenergic antagonists exert similar inhibitory effects indicating a complex role for the sympathetic nervous system in the control of pancreatic secretion.

Animals↗
PubMed1989

Nonacute subdural hematoma: fundamental interpretation of MR images based on biochemical and in vitro MR analysis.

Few reports have described the nature of the appearance of nonacute subdural hematoma on magnetic resonance (MR) images. The authors analyzed MR images in 39 cases of nonacute subdural hematoma and subdural effusion by measuring in vitro proton relaxation times and the biochemical variables of hematoma fluids. T1 became proportionally shorter than T2 with an increase in hematocrit but the direct cause of the variation in T1 and T2 was the amount of methemoglobin. The free iron content, not the bound iron content, was another main cause for shortened T1 and T2. Paradoxical findings in the correlation between the total protein or albumin concentration and relaxation times were noted. It is possible that as the protein level in the supernatant increased, more free iron was bound to the protein, decreasing the influence of the free iron on the relaxation times.

Adult↗
PubMed1989

Postprandial gastric blood flow in conscious dogs.

Left gastric arterial blood flow was measured with an electromagnetic flowmeter in conscious dogs. Immediately after the ingestion of 300 g of meat or milk, gastric blood flow increased to 250-270% of the control but declined to preprandial levels in 10 min despite the presence of milk in the stomach. Gastric distension with a 300-ml balloon evoked a response of approximately 50% of that of milk, but continuous distension failed to maintain gastric hyperemia. The initial peak response to milk and distension was reduced by hexamethonium (-58 and -62%, respectively) and oxethazaine (-43 and -29%, respectively) but not by phenoxybenzamine, propranolol, or atropine. Thus the initial response was induced by both the contact of food with the mucosa and the distension of the stomach partly via the activation of neural reflexes. Gastric blood flow after the peak was dependent on the type of food and its route of administration; it was elevated by 30% after a meat meal, remained close to fasting levels after oral administration of milk, and fell below fasting levels (-17%) after intragastric administration of milk. An intraduodenal infusion of milk, but not water, reduced gastric blood flow below the control (-26%). Pentagastrin, which caused approximately 50% of the maximal acid secretion, increased gastric blood flow by only 10%.

Animals↗
PubMed1989

Effect of cerebral ischemia and hypercapnia on cerebral pH studied with 31P-NMR and electrical activity in rat brain.

The activity of electroencephalogram (EEG) and cortical somatosensory evoked potential (SEP) was suppressed during cerebral ischemia in rats subjected to the 4-vessel occlusion. Considerable variations were demonstrated in the decrease of phosphocreatine and ATP concentration during ischemia among the rats measured with 31P-NMR, accompanied with cerebral acidification. Hypercapnia, induced in the rats studied by the inhalation of a gas mixture of 30-40% CO2, suppressed the activity of EEG and cortical SEP. The cerebral acidification observed during the ischemia was more severe than that under the hypercapnia, implying that cerebral acidification is one of the possible causes for the decrease in the electrical activity of the brain during ischemia.

Animals↗
PubMed1989

Localization of chromogranin A and B, beta-endorphin and enkephalins in the submandibular glands of mice.

The localization of chromogranin A and B, beta-endorphin, met-enkephalin and leu-enkephalin was immunocytochemically investigated in the submandibular salivary gland (SMG) and pancreas of male mice using different antibodies. Procedures were carried out with different immunocytochemical methods, such as peroxidase-antiperoxidase and indirect immunofluorescence methods, visualized with diamino-benzidine, 4-chloro-1-naphthol and FITC stainings. Chromogranin A immunoreactivity was located in the granular convoluted tubule cells (GCT), whereas chromogranin B immunoreactivity was located in some of the solitary cells scattered around the acini, but not in GCT of SMG. In the pancreas, different localizations were observed between chromogranin A and B. Beta-endorphin and met-enkephalin immunoreactivities were also located in GCT, but in the striated duct cells as well. However, met-enkephalin, but not beta-endorphin, immunoreactivity was found in the nerves around the duct system. Our results strongly suggest that chromogranin A, but not chromogranin B, may be useful as a means to differentiate the cells in the duct system of the SMG responsible for production of biologically-active factors.

Animals↗
PubMed1989

A comparative study of the localization of vasoactive intestinal peptide- and substance P-like immunoreactivities in the submandibular salivary glands of mice.

The localization of vasoactive intestinal peptide (VIP)- and substance P (SP)-like immunoreactivities within the submandibular salivary glands (SMG) of Balb/c male mice at 4 to 5 weeks of age were investigated. Two immunocytochemical methods using polyclonal, monospecific antibodies, the indirect immunofluorescence and peroxidase-antiperoxidase (PAP), were used to elucidate the localization of VIP- and SP-like immunoreactivities in the SMG. Both VIP- and SP-like immunoreactivities were positive in the SMG of Balb/c male mice at 4 to 5 weeks of age. The VIP-like immunoreactivity was found in the dense plexuses around the salivary duct and in the small scattered nerves surrounding glandular acini, and particularly in the nerve cell bodies of the submaxillary ganglion. The SP-like immunoreactivity was conspicuously abundant in the excretory ducts with a rich supply of SP-positive nerves, but also very scanty in the acinus areas close to the striated ducts and interlobular excretory ducts. It could be conclusively observed that the localization of the VIP- and SP-like immunoreactivities were different in the submaxillary ganglion, in the nerves around blood vessels and acinus areas, but very similar in the areas of the excretory and striated duct of the SMG.

Animals↗
PubMed1989

[Research on the fatigue of dentists].

Fatigue of the dentist is mainly caused by his forced working posture. Although several studies of the cause of the fatigue and its recovery way have been done, it seems that they are not practically applied to the dental field. In this study authors obtained some basic information for the fatigue of dentists and analysed them in view point of the experience year and working posture of dentists. The results were as in the following: 1) Rate of dentists to feel the fatigue after dental treatment was 26.7% in "often" on the average, and 90% including such dentists as "occasionally". There was few difference between the fatigue and the experience year and working posture, except for a number of the dentists experienced below 10 years, who felt the fatigue in "occasionally". 2) The characteristics of physical parts for appearance of the fatigue were as follows. (1) In the standing working group, "languor" of crus and back in the dentist group experienced below 10 years, and "pain" of waist in the group experienced over 30 years were recognized. The complaints of the fatigue were not so complicated. (2) In the sitting working group, "stiffness", "pain" and "languor" of waist were recognized complicatedly. The fatigue of fingers and arms were recognized only in this working group of posture. (3) In the standing and sitting combined working group, "stiffness", "pain" and "languor" of waist were recognized complicatedly in the dentists experienced over 30 years, and their rates were in high degree.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

The investigation of experimental brain tumours using 31P-MRS and 1H-MRI.

In vivo 31P-magnetic resonance spectra (MRS) were obtained by the surface coil method from rat glioma, human glioblastoma, and human neuroblastoma inoculated subcutaneously in CD Fisher rats and hamsters, and the effects of chemotherapy, photoradiation therapy, and radiofrequency hyperthermia as well as 60Co-irradiation were evaluated by sequentially observing spectral changes. In the 31P-spectra of tumour tissue, the nucleoside triphosphate (NTP), phosphomonoesters (PME) peaks were high and the phosphocreatine peak was low compared to those of normal brain. When the antitumour agents were given and were effective, NTP peaks decreased, and inorganic phosphate increased remarkably within several hours after the treatment. 1H-magnetic resonance imaging (MRI) were also obtained in some cases. Necrotic regions was detected by the 1H-MRI as image changes which appeared later than those detected by MRS. It proved practical to monitor the effect of therapy by employing either 31P-MRS or 1H-MRI. However, the image changes which demonstrated the effect of the therapy used closely resembled those changes which occurred with the onset of necrosis in tumour tissue during tumour growth. Several problems for future application of these techniques to human brain tumours are also mentioned.

Animals↗
PubMed1988

Pathophysiological investigation of experimental cerebral ischaemia using in vivo 31P-NMR spectroscopy and 1H-MRI.

The cerebral energy metabolism and brain oedema were investigated in three experimental cerebral ischaemia models using 31P-NMR spectroscopy (MRS) and 1H-NMR imaging (MRI) in the same subject animal. These measurements were performed also in experimental brain oedema models and the findings were compared with each other. 31P-MRS showed an ischaemic pattern in all of the cerebral ischaemia models, that is, ATP and PCr peaks decreased, and the Pi peak increased and shifted to a higher resonant frequency. However, 31P-MRS did not show any remarkable change in the brain oedema models. On the other hand, 1H-MRI clearly demonstrated brain oedema in the brain oedema model. In the cerebral ischaemia models, 1H-MRI findings differed depending upon the type of model, namely the most marked brain oedema was detected in the unilateral middle cerebral arterial occlusion model and no marked change was detected in the temporary four vessel occlusion model. It was thought that this difference depended on the severity of the ischaemic insult. Accordingly, the fundamental pathophysiological problem of cerebral ischaemia was the energy metabolism disturbance with the brain oedema being associated with this disturbance but occurring secondarily. However, in the brain oedema model the main pathological change was the increase in tissue water.

Animals↗
PubMed1988

Feedback regulation of basal pancreatic secretion in humans.

The effect of intrajejunal infusion of pancreatic juice on basal pancreatic secretion was studied in patients who had received pancreatoduodenectomy for pancreatic, biliary, or duodenal malignancy. Pure pancreatic juice was obtained through a drainage tube inserted into the main pancreatic duct. There was little fibrosis in the pancreatic remnant and daily pancreatic juice output was more than 200 ml. After intraluminal infusion of pancreatic juice, water, protein, bicarbonate, and enzyme outputs were decreased significantly by about 30%. Intraluminal trypsin also reduced pancreatic secretion. Trypsin inhibitor (aprotinin) suppressed the significant decrease caused by autopancreatic juice or trypsin solution. We conclude that basal pancreatic secretion in humans is under negative feedback control by intestinal pancreatic juice or tryptic activity.

Adult↗