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Biomedical subjects

I Sasaki

Publications and source records attributed to I Sasaki.

At least 91 records · Page 5Linked to original sources
PubMed1996

Modified procedure with a surgical stapler for construction of a Pavlov pouch in dogs.

An aim of this study was to establish a simple method for the construction of a Pavlov pouch that is free of fistula formation between the main part of the stomach and the pouch, yet preserves maximal vagal innervation. The Pavlov pouch (vagally innervated gastric pouch) was constructed from the greater curvature of the gastric corpus at the level of the splenic hilus in four dogs. The plane between the mucosal and seromuscular layers was dissected bluntly along the medial margin of the pouch. A surgical stapler was introduced into the space between the mucosal and seromuscular layers, and the pouch was completely separated from the main part of the stomach enterically at the mucosal level but remained connected via the seromuscular layers. All dogs survived the operation and lost minimal weight; fistulas were not found between the remnant stomach and the pouch at necropsy 6 to 8 weeks later. Gastric acid secretion for 30 to 90 min after insulin-induced hypoglycemia, which increases vagal tone, was significantly increased compared to that before insulin injection, confirming preservation of vagal innervation to the pouch. Our technique to create a Pavlov pouch is superior to the methods reported previously because of its simplicity, lower prevalence of fistula formation, and reliable preservation of vagal innervation to the pouch.

Animals↗
PubMed1996

[Non-paralytic pontine exotropia with alternating exotropia].

We report a patient with pontine infarction who showed non-paralytic pontine exotropia (NPPE) with alternating exotropia. An 81-year old woman developed diplopia and gait disturbance. On the fourth day, she was admitted to our hospital. Oculomotor findings on admission showed that the ocular position of the left eye on forward gaze was fixed at the midline, while the right eye was abducted. When she was instructed to use the right eye for forward gaze, the left eye deviated outward. On right gaze, the left eye was not abducted and monocular nystagmus was noted in the abducted right eye. Upper gaze was limited in the right eye and convergence was not possible. The remaining ocular movements were intact. On cranial CT performed on eye closure, the left eye was abducted and the right eye was fixed at the midline. Brain MRI showed cerebral infarction located in the left paramedian portion of the middle pontine tegmentum with involvement of the medial longitudinum fasciculus (MLF) and in the ventral site of the upper pons. On the 16th day, right exotropia disappeared on eye opening without forward gaze, but forward gaze easily induced outward deviation of the right eye. On the 39th day, right exotropia on forward gaze had almost disappeared. However, left MLF syndrome and abnormal convergence were persistent when she discharged on the 76th day. In conjunction with oculomotor and neuroradiological findings, the NPPE with alternating exotropia in our patient may be due to severe MLF damage and secondary hyperactivity of the contralateral paramedian pontine reticular formation.

Aged↗
PubMed1995

Specific protein interacting with a tumor promoter, debromoaplysiatoxin, in bovine serum is alpha 1-acid glycoprotein.

Aplysiatoxin and debromoaplysiatoxin, a debrominated form of aplysiatoxin, have both been shown to be potent tumor promoters in a two-stage carcinogenesis experiment on mouse skin. However, debromoaplysiatoxin did not behave like aplysiatoxin in most of the biological assay systems using cultured cells. The discrepancy was supposed to be due to a factor in the bovine serum used for culture, a similar factor not being present in sera of eight other animal species examined. The factor was purified to homogeneity from bovine serum by ammonium sulfate fractionation and chromatographies on DEAE-cellulose, Sephadex G-150, hydroxyapatite, and a reversed-phase HPLC column. The factor was a 40-kDa protein, and partial amino-acid sequencing of its tryptic peptides indicated that the factor is alpha 1-acid glycoprotein. Both the purified factor and the commercially available bovine alpha 1-acid glycoprotein abolished in vitro the activation of protein kinase C by debromoaplysiatoxin but not that by aplysiatoxin. Debromoaplysiatoxin induced differentiation of HL-60 cells into macrophages at a comparable concentration to aplysiatoxin, when serum-free medium was used. These results suggest that alpha 1-acid glycoprotein, which interacts specifically with debromoaplysiatoxin, contained in bovine serum must have masked the in vitro properties of the tumor promoter in the biological assay systems.

3T3 Cells↗
PubMed1995

Sequence analysis of cDNA for the VP6 protein of group A avian rotavirus: a comparison with group A mammalian rotaviruses.

cDNA corresponding to the genomic segment 6 of avian rotavirus strain PO-13, which has group A common and subgroup I antigens, but does not hybridize in Northern blots with RNA probes from group A mammalian rotaviruses, was cloned and sequenced. When the deduced amino acid sequence was compared between strain PO-13 and eight group A mammalian rotaviruses, the extent of homology ranged from 73-75%. An alignment of the amino acid sequences allowed us to identify three amino acids (Positions 120, 317 and 350) that may contribute to determining the subgroup epitopes. A phylogenetic tree constructed on the basis of nucleotide substitutions in the VP6 gene of nine rotaviruses strongly suggests that the avian rotavirus is an ancestral prototype of mammalian rotaviruses.

Amino Acid Sequence↗
PubMed1995

Intragastric capsaicin stimulates colonic motility via a neural reflex in conscious dogs.

BACKGROUND & AIMS: Capsaicin is known to contract smooth muscles and to have an excitatory action on thin, primary afferent neurons. The aim of this study was to test the hypothesis that intragastric capsaicin may have an excitatory effect on colonic motility. METHODS: Mongrel dogs equipped with five strain-gauge force transducers on the colon (C1-C5) were used. In 5 dogs, the effect of intragastric capsaicin (0.05, 0.1, 0.3, and 0.5 mg/kg) on colonic motility in the presence or absence of the cholinergic blockers atropine and hexamethonium was studied. In 4 dogs, the effect of capsaicin (0.5 mg/kg) administration into a vagally innervated or denervated gastric pouch on colonic motility was investigated. RESULTS: Motility at C2-C3, C1-C3, and C1-C5 was significantly increased by 0.1, 0.3, and 0.5 mg/kg of capsaicin, respectively. The excitatory effect of capsaicin on colonic motility was inhibited by atropine and hexamethonium. Colonic motility at C1-C4 was significantly increased by capsaicin administration into a vagally innervated pouch but was not affected by capsaicin administration into a vagally denervated pouch. CONCLUSIONS: These results indicate that intragastric capsaicin predominantly stimulates motility in the proximal half of the colon through neural pathways, probably through a vagovagal reflex, but sympathetic involvement cannot be excluded.

Animals↗
PubMed1995

Effects of 8-OH-DPAT on corticosterone after acute and chronic administration of antidepressants.

1. Serotonin has a facilitary role in the role of corticosterone secretion. 8-Hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), a selective 5-HT1A agonist, dose dependently (0.25- 1.0 mg/kg i.p.) increased rat plasma corticosterone concentration. 2. 3 days parachlorophenylalanine (PCPA) (150 mg/kg) administration did not effect the 8-OH-DPAT-induced corticosterone secretion. 3. Corticosterone responses to 8-OH-DPAT (0.5 mg/kg) were significantly attenuated by pretreatment with propranolol (5 mg/kg). Ketanserin (2 mg/kg), haloperidol (0.2 mg/kg), prazosin (0.1 mg/kg), and ICS-205930 (30 mu/kg) failed to antagonize the corticosterone response to 8-OH-DPAT. 4. 8-OH-DPAT-induced corticosterone were investigated in male rats after treatment with mianserin (2, 10 mg/kg), imipramine (5 mg/kg), desipramine (5 mg/kg), doxepine (5 mg/kg) for 1 day or 3 weeks. Chronic mianserin (10 mg/kg) and doxepine (5 mg/kg) did significantly increase 8-OH-DPAT-induced corticosterone response. Acute antidepressant, chronic imipramine, desipramine and mianserin (2 mg/kg) treatment did not change it. 5. These findings demonstrate that chronic treatment of some antidepressants potentiates 8-OH-DPAT-induced increase in plasma corticosterone, by actions at 5-HT-1A receptors located postsynaptically on 5-HT neurones.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1995

Intestinal absorption of azetirelin, a new thyrotropin-releasing hormone (TRH) analogue. II. In situ and in vitro absorption characteristics of azetirelin from the rat intestine.

Intestinal absorption characteristics of azetirelin, a new thyrotropin-releasing hormone (TRH) analogue, were studied in rats by means of in situ closed loop and in vitro everted sac experiments. Plasma concentrations of azetirelin obtained in the in situ closed loop experiments were not significantly different among the intestinal segments. Area under the plasma concentration-time curve (AUC) of azetirelin following administration into the duodenal loop increased in proportion to the dose. The serosal to mucosal concentration ratio of the analogue in the everted sac experiment was constant over the mucosal drug concentration range of 0.01-10 mM. There was no directional difference in the transfer rate of azetirelin across the everted and non-everted sacs of the duodenum. Furthermore, its transport across the duodenum was not influenced by low incubation temperature (25 degrees C), addition of dipeptide (Gly-Gly), or pretreatment of the mucosal surface with 2,4-dinitrophenol, while that of TRH was inhibited under these conditions. These results suggest that the intestinal absorption mechanism of azetirelin is different from that of TRH, and that azetirelin is predominantly transported via a passive diffusion.

Amino Acid Sequence↗
PubMed1995

[Gastric emptying of semi-solid meal in normal man with special reference to relationship between plasma acetoaminophen concentrations and gastric emptying time].

Correlation between gastric emptying time measured by a radioisotope method and plasma acetoaminophen level was studied in 11 preoperative early gastric cancer in semisolid meal. A significant correlation was found between both gastric emptying half-time and plasma acetoaminophen level at 30, 45 minutes after ingestion of meal, and plasma acetoaminophen level at maximum. We conclude that acetoaminophen analysis is useful to measure gastric emptying at semisolid meal.

Acetaminophen↗
PubMed1995

Gastric mucosal phosphatidylcholine hydroperoxide increases during cold water-immersion restraint stress in rats.

To know the role of lipid peroxidation in the pathogenesis of stress-induced gastric mucosal lesions, we performed the present study. Both gastric mucosal lesions and gastric mucosal phosphatidylcholine hydroperoxides (PCOOH) levels during cold water-immersion restraint (CWIR) stress were measured by the chemiluminecence-HPLC method in Sprague-Dawley rats. Ulcer indices increased time-dependently during the stress. Gastric mucosal PCOOH levels also significantly increased and reached a peak level (250% of untreated level) after 2 hr of stress. These results suggest that lipid peroxidation may play an important role in the pathogenesis of gastric mucosal lesions induced CWIR stress.

Animals↗
PubMed1995

Effect of motilin on colonic motor activity in the interdigestive state in conscious dogs.

The aim of the present study was to investigate the effect of motilin at various doses on colonic motility in the interdigestive state. Colonic motility was investigated in five dogs equipped with strain gauge force transducers on the gastric antrum, and on the proximal, middle, and distal colon. Exogenously infused motilin (0.2, 0.5, 1.0 and 2.0 micrograms/kg-hr) dose-dependently increased colonic motility, but the doses of motilin that significantly enhanced colonic motility were 1.0 and 2.0 micrograms/kg-hr in all areas of the colon. Motilin at 0.2 microgram/kg-hr increased the plasma motilin concentration to almost equal to the physiological peak values. The excitatory effect of motilin (2.0 microgram/kg-hr) was abolished by atropine but was not affected by hexamethonium. These results indicate that exogenously infused motilin, which increased plasma motilin concentration to above the physiological peak level, stimulated colonic motility by affecting postsynaptic cholinergic neurons.

Animals↗
PubMed1995

Effect of chronic pancreatic juice diversion on enteroglucagon secretion and intestinal mucosal growth in dogs.

We developed a new canine model of chronic pancreatic juice diversion from duodenum to distal ileum in order to investigate the effect of pancreatic juice on the secretion of enteroglucagon, and the growth of intestinal mucosa. In seven adult mongrel dogs, the minor pancreatic duct was ligated and excised. Then, 3 cm of duodenal segment including the pancreatic duct was transformed into a small pouch which was anastomosed to the distal ileum. Butter ingestion tests were performed before and after surgery to evaluate the effect of surgery on enteroglucagon secretion. In addition, intestinal mucosal thickness was measured, using specimens taken both at the time of surgery and during autopsy at the end of the study. We observed significant hypersecretion of enteroglucagon and mucosal growth throughout the whole small intestine. However, extent or grade of mucosal growth was not related to the mucosal contact of pancreatic juice. These results suggested that chronic pancreatic juice diversion from duodenum to the distal ileum induced mucosal growth of the whole small intestine and hypersecretion of enteroglucagon may play a important role in this growth.

Amylases↗
PubMed1995

Gastrointestinal motor activity after pylorus-preserving gastrectomy with or without vagotomy in dogs.

BACKGROUND: In the present study we evaluated gastrointestinal motility after gastrectomy of a new pylorus-preserving technique that is becoming a popular operation for early stage carcinoma of the stomach. STUDY DESIGN: Using strain-gauge force transducers we studied gastrointestinal motility in control dogs, dogs after pylorus-preserving gastrectomy, and dogs after conventional distal gastrectomy with Billroth I reconstruction. Dogs with gastrectomy were reoperated upon after recording motility patterns, and the effect of vagal denervation of the gastric remnant on motility was investigated. Overall motility pattern, length of the digestive phase in the jejunum, and interval of the interdigestive phase III contractions were studied and compared among the three groups. RESULTS: In dogs after gastrectomy without vagal denervation, the regular occurrence of interdigestive phase III contractions from the gastric remnant to the jejunum was identified. In dogs after gastrectomy with vagal denervation, however, no apparent interdigestive phase III contractions were observed in the gastric remnant. The duration of the digestive phase in the jejunum, which correlates with postprandial gastric emptying, was not different between the control dogs and the dogs having pylorus-preserving gastrectomy. However, this duration was significantly shorter in dogs having conventional distal gastrectomy compared with the control dogs, not only before but after vagal denervation. CONCLUSIONS: These results indicate that the postoperative motor function after pylorus-preserving gastrectomy may be superior to that after conventional distal gastrectomy with Billroth I reconstruction.

Animals↗
PubMed1995

[A case of mitochondrial encephalomyopathy with peripheral neuropathy and autonomic symptoms].

We report a 28-year-old man with mitochondrial encephalomyopathy with peripheral neuropathy and autonomic symptoms. Muscle biopsy from the quadriceps femoris muscle showed myopathic changes with ragged-red fibers and abnormal mitochondria. He experienced recurrent and acute weakness in his bilateral lower limbs. Needle electromyogram revealed neurogenic changes, and the amplitude of muscle action potential was low in the right posterior tibial nerve. Sural nerve biopsy showed a marked loss of both large and small myelinated fibers, and moderate to severe axonal degeneration was diagnosed. He experienced autonomic symptoms (nausea, constipation, hypoidosis and urinary retention) along with the weakness in his lower limbs which is considered to be a very rare situation. We hypothesized that autonomic symptoms in this case were due to the axonal degeneration that included unmyelinated fibers.

Action Potentials↗
PubMed1995

Diagnostic value of endoscopic ultrasonography in an unusual case of gastric cyst.

Using endoscopic ultrasonography, we diagnosed a gastric antral submucosal cyst with a papillous protrusion in a 71-yr-old woman, apparently the first such case to be detected by this method. Endoscopic ultrasonography demonstrated a well-marginated hypoechoic area with papillary tumor in the submucosal layer that did not extend to the muscularis propria. The lesion was diagnosed as a gastric submucosal cyst. CT and transabdominal ultrasound each failed to detect the intracystic papillary tumor. Follow-up endoscopic ultrasonography performed 6 months later revealed an increase in the diameter of the cyst and the papillary tumor. The patient then underwent a partial gastrectomy for a suspected malignancy. The resected specimen showed a cystic lesion with papillary tumor. Although no malignancy was present, examination of cross-sections of the resected specimen gave results consistent with the endoscopic ultrasonographic findings. Endoscopic ultrasonography is thus useful in assessing the nature of a submucosal gastric cyst in detail and in monitoring patients with this lesion.

Aged↗
PubMed1995

[A case of facial diplegia in associated with reactivation of herpes simplex virus type I].

A 27-year-old Japanese man developed right peripheral facial palsy after suffering from a cold and low-grade fever for 7 days. Left peripheral palsy developed 4 days later. When he visited our hospital 3 days after that, neurological examination revealed no abnormalities except peripheral facial diplegia. Cerebrospinal fluid (CSF) was normal on admission and on hospital day 12. On admission, the patient had a transient increase of serum titers of HSV type I IgM (fluorescence assay). Then, serum titers of HSV type I IgG (ELISA) continuously increased. A diagnosis of peripheral facial diplegia due to reactivation of HSV type I was made clinically and serologically. Steroid pulse therapy was performed and his facial diplegia disappeared completely after 2 weeks. This case may support the hypothesis of virus etiology of Bell's palsy, and HSV type I should be considered as one of the possible causes of facial diplegia.

Adult↗
PubMed1994

Intestinal absorption of azetirelin, a new thyrotropin-releasing hormone (TRH) analogue. I. Possible factors for the low oral bioavailability in rats.

Absorption of azetirelin, a new thyrotropin-releasing hormone (TRH) analogue, from the gastrointestinal (GI) tract was evaluated. The bioavailability of this compound after oral administration was considerably poor in rats. Studies were undertaken to elucidate the mechanisms for this low oral bioavailability of azetirelin. The plasma azetirelin levels following intravenous and hepatoportal vein injection were virtually identical over the dose range of 0.02-0.1 mg/kg, indicating a minor contribution of the hepatic first-pass metabolism of this drug. Azetirelin was stable against peptide hydrolases both in luminal fluid and intestinal mucosal homogenates, whereas its degradation occurred when incubated with cecal contents under an anaerobic condition. In addition, complete degradation of azetirelin during the GI transit was disclosed by analyzing the fecal sample collected after oral administration of [14C]azetirelin. These results suggested that gut bacteria may be responsible for the hydrolysis of azetirelin in the GI tract. The low intestinal permeability of azetirelin was revealed by a modified everted gut experiment in various segments of the rat intestine. The poor membrane transport characteristics of azetirelin may be due to its high hydrophilicity. From these results, it was suggested that the insufficient oral bioavailability of azetirelin may be mainly attributed to its low intestinal permeability due to a lack of lipophilicity, and also to the degradation of the peptide by intestinal microflora.

Administration, Oral↗