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Biomedical subjects

M Sakaguchi

Publications and source records attributed to M Sakaguchi.

At least 325 records · Page 18Linked to original sources

Cardiopulmonary effects of a combination of medetomidine and butorphanol in atropinized pigs.

Cardiopulmonary effects of a combination of medetomidine and butorphanol were evaluated in atropinized pigs. This combination unchanged the cardiac output and significantly lowered the oxygen consumption compared with base-line values. Although some statistically significant changes were recorded, both medetomidine and butorphanol did not have a marked effect on the cardiopulmonary parameters in atropinized pigs. It was indicated that the administration of the combination of medetomidine and butorphanol is relatively safe in atropinized pigs.

Adrenergic alpha-Agonists↗

[Antibody responses against Japanese cedar pollen allergen (Cry j I) in different strains of rats].

We established an IgE-capture ELISA for rat IgE antibody, and examined rat strain differences in the antibody responses against the major allergen of Japanese cedar pollen (Cry j I). First, IgE-capture ELISA and passive cutaneous anaphylaxis (PCA) method were compared. IgE-capture ELISA was found to be, in sensitivity, about 10 times higher than, and, in specificity, equal to, PCA. Second, seven strains of rat were immunized three times at days 0, 14 and 28 by intraperitoneal injections of 1 or 10 micrograms Cry j I mixed with 4 mg aluminium hydroxide gel. Anti-Cry j I IgE was detected by IgE-capture ELISA. Anti-Cry j I IgG and IgM responses were found not significantly different among different strains, but IgE responses in Brown-Norway (BN) rat were about 10 times higher than in other strains of rats. These results suggest that BN rat may be a useful animal model for studying physiological and pathological changes in the nose after pollen challenge to that organ.

Allergens↗

[Thirteen-week repeated dose toxicity by oral administration of trandolapril (RU44570) with 4-week recovery test in beagles].

Trandolapril (RU44570) was orally administered to dogs at a daily dose of 2.5, 25 or 250 mg/kg for 13 weeks. After the administration period, 25 and 250 mg/kg groups were observed for recovery for 4 weeks. The results obtained are as follows: 1. One male in the 250 mg/kg group showed decrease of food consumption and body weight, stomatitis, hematemesis, decumbence, hypothermia, and finally loss of reactivity to stimuli. This animal was killed because of these severe changes on the 39th day of administration. Among the surviving animals, a temporary loss of body weight was observed in a few animals of the 25 and 250 mg/kg groups, and a decreased food consumption was sporadically seen in a few animals of the 250 mg/kg group during the administration period. No abnormal changes were found in the clinical observation and water intake in the surviving animals. 2. The changes attributable to the pharmacological effect of RU44570 were a decreased activity of the angiotensin-converting enzyme, increases in plasma renin activity and urine volume, and decreases in specific gravity and concentrations of Na, K and Cl in the urine of every administration group. A decrease in blood pressure and an increase in the PAS and Bowie positive granules in the juxtaglomerular cells were also found in the 25 and 250 mg/kg groups. In addition, thickening of the afferent arteriolar wall of the glomeruli, a basophilic change of the renal tubular epithelial cells, and localized atrophy and hypertrophy of the renal tubules were observed in the 25 and 250 mg/kg groups, and increases in BUN, ALP and creatinine, and a slight dilation of the renal tubules were seen in the 250 mg/kg group. These observations indicated that RU44570 affected renal structure at a dose of 25 mg/kg or more renal function at a dose of 250 mg/kg. The animal killed in a moribund state showed nephrosis which consisted mainly of a moderate dilation of the renal tubules and vacuolation of the renal tubular epithelial cells, stomatitis, severe hemorrhage and necrosis with neutrophil infiltration in the fundus of the glandular stomach, atrophy of the hemopoietic system, and ectopic calcification in the heart, kidneys, stomach, trachea and alveolar wall. Changes in the kidneys similar to those observed in other animals were also detected. These changes suggested that this animal lapsed into a moribund state due to renal dysfunction and the resultant uremia.(ABSTRACT TRUNCATED AT 400 WORDS)

Administration, Oral↗

[A clinical study of pathophysiology and treatment of intractable gastric ulcers based on 24-hour intragastric pH monitoring].

The 24-hour intragastric pH monitoring was conducted in patients with gastric ulcers treated with an H2 blocker, and the pathophysiological conditions and the treatment of intractable gastric ulcers were studied from the aspect of degree of intragastric acidity. During the administration of a standard dose of an H2 blocker, there was no difference of intragastric acidity at night between intractable gastric ulcers and tractable gastric ulcers. However, intragastric acidity was significantly higher during the day in the intractable gastric ulcers. The pH 3 holding time rate during the day in all intractable gastric ulcer patients was less than 45%; however, in the tractable gastric ulcer patients it was more than 45% during the day. In treating intractable gastric ulcers, if combined administration of synthetic prostaglandin E2 having a suppressing action of gastric acid secretion was performed or if the drug was changed to a proton pump inhibitor, a rise in intragastric pH was observed and earlier cure was obtained. That is to say, intractable gastric ulcers are characterized by inadequate suppression of gastric acid during the day, and it is surmised that if gastric acid can be adequately suppressed not only during the night but also during the day, no matter which drug or administration method is used, it will be effective against intractable gastric ulcers.

Adult↗

[Interaction of midazolam and vecuronium in anesthetized patients].

The interaction between midazolam and vecuronium was investigated in 60 patients during isoflurane-nitrous oxide-oxygen anesthesia. Neuromuscular function was evaluated by recording the single twitch of the abductor pollicis muscle. Anesthesia was induced with thiamylal 4 mg.kg-1 or midazolam 0.2 mg.kg-1 followed by injection of vecuronium 0.1 mg.kg-1. Observed values after midazolam were compared with those observed in patients with thiamylal. the onset time and the duration of action until 25% recovery were similar with both groups. Midazolam caused no significant potentiation of neuromuscular blocking agents in comparison with the control. Therefore, there was no evidence of any interaction between midazolam and vecuronium during isoflurane-nitrous oxide-oxygen anesthesia.

Adult↗

[A case report of Weber's syndrome associated with supranuclear vertical gaze palsy caused by the ipsilateral thalamomesencephalic lesion].

We report a rare case showing Weber's syndrome associated with supranuclear vertical gaze palsy caused by the ipsilateral lesion of the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF), which is regarded as the supranuclear control center of vertical gaze. To date, no literature concerning Weber's syndrome associated with the ipsilateral riMLF lesion was documented. The patient was a 53-year-old female, who suddenly developed unconsciousness and left-sided weakness. Neurological findings on admission revealed right third nerve palsy, severe supranuclear vertical gaze palsy, almost complete convergence palsy, left hemiparesis and hyperreflexia with positive Babinski's sign on the left side. There was no sign of pupillary disturbance or no abnormality of the horizontal movements of the left eye. The vestibulo-ocular reflex of the left eye was preserved. There was no sensory disturbance. Cranial MRI had the advantages in demonstrating unilateral ischemic lesions at the cerebral peduncle and the thalamomesencephalic junction involving the unilateral riMLF on the right side. Recent reports have demonstrated that supranuclear vertical gaze palsy is caused by the unilateral riMLF lesion. We confirm that the unilateral riMLF lesion causes supranuclear vertical gaze palsy in our case and that cranial MRI has the advantages in demonstrating the specific lesion.

Eye Movements↗

Confirmation of the airborne occurrence of micron-size airborne pollen antigen carrying particles by immunoblotting.

We confirmed the existence of micron-size airborne particles carrying major pollen antigen of Cryptomeria japonica (Cry j l) and Lolium perenne (Lol p l) by means of an immunoblotting technique and examination by light microscopy. The size of the spots on a nitrocellulose membrane, marking the presence of antigen on the sampler's tape, varied considerably under light microscopic examination. Spots smaller than pollen grains and micron-size spots were observed together with large spots which seem to have been derived from intact pollen grains. The number of micron-size spots counted under a light microscope did not correspond with the number of spots from pollen grain observable with the naked eyes. This suggests other sources of airborne Cry j l particles than intact pollen grains alone.

Air↗

Degeneration of motor nerve fibers enhances the expression of calcitonin gene-related peptide in rat sensory neurons.

Calcitonin gene-related peptide (CGRP) in skeletal muscle is of neural origin. After degeneration of sensory fibers induced by removal of the lumbar dorsal root ganglia (DRG), the CGRP content in the rat soleus muscle was reduced to about 5% of the normal level. In contrast, degeneration of motor fibers induced by sectioning of the lumbar ventral roots markedly increased the CGRP content in the soleus muscle and CGRP levels in the lumbar DRG. It is suggested that the expression of CGRP in sensory neurons is up-regulated by some humoral factor induced by degeneration of motor nerve fibers.

Animals↗

Functions of signal and signal-anchor sequences are determined by the balance between the hydrophobic segment and the N-terminal charge.

The signal sequence of secretory proteins and the signal-anchor sequence of type II membrane proteins initiate the translocation of the following polypeptide segments, whereas the signal-anchor sequence of cytochrome P-450-type membrane proteins mediates the membrane insertion of the polypeptide via a signal-recognition particle-dependent mechanism but does not lead to the translocation of the following C-terminal sequences. To establish the structural requirements for the function of signal and signal-anchor sequences, we constructed chimeric proteins containing artificial topogenic sequences in which the N-terminal net charge and the length of the hydrophobic segment were systematically altered. Utilizing an in vitro translation-translocation system, we found that hydrophobic segments consisting of 7-10 leucine residues functioned as signal sequences whereas segments with 12-15 leucine residues showed different topogenic functions, behaving as signal sequences or P-450-type signal-anchor sequences, depending on the N-terminal charge. From these observations, we propose that the function of N-terminal topogenic sequences depends on a balance between the N-terminal charge and the length of the following hydrophobic segment.

Base Sequence↗

Effects of short-term administration of recombinant human erythropoietin on rat megakaryopoiesis.

Recombinant human erythropoietin (rHuEpo) was tested for its ability to stimulate rat megakaryopoiesis in vivo. Groups of Sprague-Dawley rats were injected with rHuEpo at a daily dose of 20, 80, or 200 U for 5 days. Significant thrombocytosis (a 30 to 40% increase over the control level) was found only in the rats that received 200 U/day, but some changes in the megakaryopoietic parameters were observed not only in the rats given 200 U/day, but also in those receiving 80 or 20 U/day. rHuEpo induced a dose-dependent elevation of megakaryocyte ploidy, with the maximum 45% increase in the mean ploidy over the control level seen in rats given 200 U/day. The size of the marrow megakaryocytes also increased dose-dependently. rHuEpo did not increase bone marrow megakaryocyte numbers, but it increased those in the spleen in a dose-dependent manner. A change of these parameters was seen as early as day 1 at 24 h after initiating the Epo injections at a time when significant thrombocytosis was already present. Moreover, a significant increase in the ratio of small acetylcholinesterase-positive bone marrow cells was also found, with the greatest response noted on day 1. Administration of a large dose of iron did not alter the thrombopoietic effect of rHuEpo. These results suggest that the in vivo administration of rHuEpo stimulates the maturation of mature as well as immature megakaryocytes already present in the bone marrow.

Animals↗

Sequence determination and genetic content of an 8.9-kb restriction fragment in the short unique region and the internal inverted repeat of Marek's disease virus type 1 DNA.

The DNA sequence (8.9 kb) covering about 70% of the short unique region (Us) and part of the short inverted repeat of the Marek's disease virus type 1 GA strain was determined. Computer analysis of the sequence showed the presence of nine potential open reading frames (ORFs), consisting of more than 300 nucleotides in the Us region. Of these ORFs, four were found to be homologous to US10 (minor virion protein), US3 (protein kinase), US2, and US6 (gD) in the Us region of alpha-herpesvirus herpes simplex virus type 1. The protein kinase homologue is especially well conserved in alpha-herpesviruses. No counterpart of the nine MDV1 ORFs was found in the beta-herpes virus human cytomegalovirus and gamma-herpesvirus Epstein-Barr virus, suggesting that MDV1 is more similar to the alpha-herpesviruses. The junction of the Us region and the short inverted repeat was also determined by comparison between the sequences of the DNA fragments, including the terminal and internal repeats. Northern blot analysis showed that the Us region within the 8.9 kb sequence was transcriptionally active in MDV1-infected cells.

Amino Acid Sequence↗

Pharmacokinetics of intratumoral RK-28, a new hypoxic radiosensitizer.

RK-28 is one of the new hypoxic cell radiosensitizers being developed in Japan and has been tested clinically. To reduce its toxicity and increase its sensitizing activity, intratumoral injection of RK-28 was performed during intraoperative radiation therapy for pancreatic cancer. This report presents the results of pharmacokinetic studies performed in 10 of the 17 patients who were administrated intravenous or intratumoral RK-28 during intraoperative radiation therapy. No adverse effects were noted following intravenous or intratumoral injection of the drug. Pharmacokinetic studies demonstrated several metabolites of RK-28 in both serum and tumor tissues. After intratumoral injection, the tumor drug concentration ranged from 123 micrograms/g to 9,292 micrograms/g just after intraoperative radiation therapy (30-50 min after injection of the compound), while the serum concentration ranged from 4.1 to 9.8 micrograms/ml. The tumor drug concentration was 23.3 micrograms/g at 45 min after intravenous injection of RK-28. Thus, intratumoral injection of RK-28 was superior to intravenous administration in this pharmacokinetic study. The combination of intraoperative radiation therapy and intratumoral injection of RK-28 appears to be a feasible treatment method.

Adult↗

Radiosensitization by 2-nitroimidazole nucleoside analog RP-170: radiosensitizing effects under both intravenous and oral administration.

The radiosensitizing activity, pharmacokinetics and toxicity of RP-170, 2-nitroimidazole nucleoside analog, were investigated and compared with those of etanidazole (SR-2508). An intravenous administration (i.v.) of 100 mg/kg of RP-170 or the same dose of etanidazole showed an equal sensitizer enhancement ratio (SER) of about 1.4 to solid EMT6 tumor under in vivo-in vitro assay and a virtually equal SER of 1.4-1.5 to solid SCC VII tumor under tumor growth delay assay. As predicted from the low partition coefficient, lower drug levels in neural tissue and more rapid serum elimination of RP-170 and etanidazole produced lower acute toxicity than lipophilic sensitizers (e.g., misonidazole). The major advantage of RP-170 over etanidazole is that it has a second route of administration. In contrast to etanidazole, in which the administration route is limited to intravenous injection, with RP-170 oral administration also exhibited effective distribution to tumors, sensitizing radiation activity to solid EMT6 and SCC VII tumors. Moreover, LD50 in mice of RP-170 (4.3 g/kg on i.v.) was increased to 5.2 g/kg by oral administration. This availability of two routes of administration indicates RP-170 as a promising hypoxic cell radiosensitizer for clinical use.

Administration, Oral↗

Mitochondrial porin can be translocated across both endoplasmic reticulum and mitochondrial membranes.

Mitochondrial porin is a major integral membrane protein of the outer membrane. To assess the stop-transfer sequence in the yeast porin molecule (P), we constructed the following chimeric proteins. (i) The signal sequence of interleukin 2, a secretory protein, was fused to the amino-terminus of porin (SP). (ii) The matrix targeting presequence of cytochrome c oxidase subunit IV was fused to the amino-terminus of porin (CP). (iii) The amino-terminal segment consisting of 42 amino acid residues of "70 kDa protein" of yeast mitochondria, a major membrane protein of the outer membrane, was introduced into the middle portion of interleukin 2 (IL70). These chimeric proteins were expressed with an in vitro transcription-translation system and their integration into microsomal membrane or mitochondrial membranes was examined. When the proteins were synthesized in vitro with wheat germ cell-free system in the presence of rough microsomal membrane (RM), SP was completely translocated across the membrane, processed by the signal peptidase, and glycosylated. The translocation of IL70 molecule across RM was stopped at the introduced amino-terminal segment of 70 kDa protein. The authentic porin did not interact with the microsomal membrane. To assess the interaction with mitochondria, porin and CP were synthesized with the reticulocyte lysate system and subjected to posttranslational import reaction with isolated rat liver mitochondria. The authentic porin was integrated into the outer membrane in an alkali-resistant fashion. CP was imported into the mitochondria and its presequence was cleaved by the processing protease in the matrix.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗

Concentration of airborne mite allergens (Der I and Der II) during sleep.

Using a low-noise air sampler and a sensitive radioimmunoassay, we measured the concentration of mite allergens in the air during sleeping with Japanese bedquilts (futon). The airborne allergen levels of Der I (Der p I plus Der f I) and Der II during sleep were 223 and 87.1 pg/m3 of air, respectively. These levels were about 10-fold higher than those during usual domestic life in the living room of the same houses. When the bedquilts were changed to new ones free of mite allergens, the airborne allergen levels of Der I and Der II were decreased to 11.5 and 12.0 pg/m3, respectively. This indicated that the mite airborne allergens during sleep were generated from the used bedding, not from the floor. We believe that exposure to airborne mite allergens during sleep might be an important factor in the development of mite allergies.

Air Pollution, Indoor↗

[A case of Vibrio cholerae non-O1 septicemia with liver cirrhosis].

A case of Vibrio cholerae non-O1 septicemia is described in this paper. A 45-year-old male with a three year history of liver cirrhosis, was admitted to our division with hematemesis, abdominal pain, high fever and a loss of consciousness. Three days before onset of symptoms, he traveled to Ishigaki Island and ate a raw lobster. Two days after, his temperature rose to 39.7 degrees C and the blood pressure dropped to 36/- mmHg. By endoscopic examination, an ulcer was found in the stomach, and the bleeding was stopped by electrical coagulation. Blood culture showed growth of V. cholerae non-O1. The organism was found to be sensitive to OFLX, CZX, MINO, LMOX and CP. Although DIC, infections of fungus and MRSA occurred as complications, he recovered by adequate procedures. Subsequently, he left this division after eight weeks. There are various reports related to V. cholerae non-O1 septicemia in foreign countries, but few cases have been reported in Japan. And these cases had severe underlying diseases such as leukemia and liver cirrhosis.

Bacteremia↗