PubMed Health⌕ Search

Biomedical subjects

N Hanyu

Publications and source records attributed to N Hanyu.

16 recordsLinked to original sources
PubMed1992

Characterization of a transthyretin-related amyloid fibril protein from cerebral amyloid angiopathy in type I familial amyloid polyneuropathy.

Recently, it has been reported that transthyretin (TTR)-immunoreactive amyloid deposition with cerebral amyloid angiopathy in central nervous system is a common pathological finding in type I familial amyloid polyneuropathy (FAP). In the present study, we performed isolation and sequence analysis of TTR-related amyloid fibril protein from the meninges of a patient with type I FAP. Purified major amyloid fibril protein had a molecular weight of 15 kDa. Complete sequence analysis revealed that this amyloid fibril protein was a variant TTR with a single amino acid substitution of methionine for valine at position 30. This variant TTR is a previously unrecognized as cerebrovascular amyloid fibril protein. Furthermore, the patients with type I FAP are well known to have the variant TTR in the serum. These suggest that cerebrovascular amyloid fibril protein in type I FAP may derive from a serum precursor.

Amino Acid Sequence↗
PubMed1992

Serial computed tomographic and electroencephalographic studies in Creutzfeldt-Jakob disease.

The serial changes in computed tomography (CT) as correlated with the clinical and electroencephalographic findings were evaluated in 3 patients with Creutzfeldt-Jakob disease. The disease was subsequently confirmed histologically in 2. CT revealed that brain atrophy began in an early clinical stage and was prominent even before the state of akinetic mutism. Periodic synchronous discharges (PSDs) were observed either before or simultaneous with the observation of myoclonus. With progressive brain atrophy, the frequency of PSDs and the degree of myoclonus both decreased and disappeared 8 to 15 months after the onset of disease.

Aged↗
PubMed1992

Leukoencephalopathy induced by tegafur: serial studies of somatosensory evoked potentials and cerebrospinal fluid.

A case of leukoencephalopathy induced by tegafur, an antineoplastic derivative of 5-FU, is reported. The patient received 600 mg of tegafur p.o. for 16 days before excision of rectal cancer. After the operation, gait disturbance and mental abnormalities appeared. He became akinetic and mute within a few days following readministration of tegafur. Serial studies of brain CT, somatosensory evoked potentials (SEP) were made, and myelin basic proteins (MBP) in the cerebrospinal fluid were measured. The level of MBP was about twice the normal value and the central conduction time (CCT) of SEP was prolonged at admission. The value of MBP and CCT improved with recovery from akinetic mutism.

Akinetic Mutism↗
PubMed1991

Effect of two new cholecystokinin antagonists on gallbladder emptying in opossums.

In this investigation we evaluated the effect of two new cholecystokinin (CCK) antagonists, CR 1409 and L364,718, on gallbladder emptying in the opossum. Gallbladder emptying was elicited by both exogenous and endogenous CCK. The three test challenges were 1) intravenous infusion of CCK octapeptide (OP) (10 ng.kg-1.min-1), 2) feeding, and 3) intraduodenal infusion of Isocal (0.4 ml/min), a fat-containing nutrient. During control conditions each test challenge elicited approximately 60% gallbladder emptying within 30 min and 70% emptying by 60 min. At given doses both CR 1409 and L364,718 substantially antagonized or abolished the gallbladder emptying elicited by each of the test challenges. The antagonism for postprandial gallbladder emptying was diminished between 30 and 50 min compared with that for CCK-OP infusion and intraduodenal infusion of Isocal. Unexpectedly, the gallbladder emptying induced by infusion of motilin (5 micrograms.kg-1.h-1) was antagonized by either CR 1409 or L364,718. In anesthetized animals, gallbladder contraction was induced by a variety of agonists, such as bethanechol, histamine phosphate, 5-hydroxytryptamine, and phenylephrine. In this later model CR 1409 and L364,718 functioned solely as selective antagonists. We conclude that for the opossum gallbladder 1) the CCK antagonists CR 1409 and L364,718 antagonize or abolish gallbladder emptying induced by exogenous or endogenous CCK; 2) the pattern of CCK antagonism after feeding suggests that the early phase of postprandial gallbladder emptying is mediated by a mechanism other than endogenous CCK, whereas late postprandial emptying is mediated by release of endogenous CCK; and 3) CR 1409 and L364,718 are not totally specific antagonists for gallbladder CCK receptors alone but also antagonize gallbladder contraction induced by motilin.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Muscular pseudohypertrophy in an adult case with centronuclear myopathy.

We describe a 40-year-old male case with centronuclear myopathy showing a unique clinical picture of generalized muscular pseudohypertrophy. CT scan, ultrasound imaging and histopathological studies of muscles revealed that muscle enlargement in this case might be caused by marked intrafascicular fatty infiltration. It is suggested that muscular pseudohypertrophy may occur in adult centronuclear myopathy cases with a long clinical course and that CT and ultrasound scans are very useful for the evaluation of diseased muscles.

Adipose Tissue↗
PubMed1991

[Diagnosis of familial amyloid polyneuropathy--gene analysis with primer-directed enzymatic amplification of DNA, isolation of plasma variant prealbumin and immunohistochemical identification of tissue amyloid protein].

Type I familial amyloid polyneuropathy (FAP) is an autosomal dominant hereditary generalized amyloidosis characterized by polyneuropathy and autonomic nerve failure. The main component of the amyloid fibril protein in this disorder has been shown to be a variant prealbumin with a single substitution of a methionine residue for valine at position 30. In the present study we have investigated 19 patients with FAP aged 31 to 67 and an asymptomatic family member using gene analysis with primer-directed enzymatic amplification (PCR) of DNA, isolation of plasma variant prealbumin and immunohistochemical identification of tissue amyloid protein. All patients and a symptom-free boy in the affected family had the mutant prealbumin gene showing abnormal DNA fragments by treatment with restriction endonuclease Bal I, and plasma variant prealbumin was also detected in all of them by reverse-phase high performance liquid chromatography. Rectum biopsies obtained from 9 patients showed amyloid deposits which were specifically immunostained by anti-human prealbumin antiserum. However, an asymptomatic carrier at the age of 16 showed no rectal amyloid deposition. Recent studies of FAP have disclosed that the expression of type I FAP is closely associated with the gene mutation of prealbumin. Accordingly, a simple and rapid method to detect this gene abnormality using PCR technique is considered to be very useful for diagnosis of type I FAP and can also provide valuable information for the genetic counselling of the family members at risk.

Adolescent↗
PubMed1991

[Gallbladder function and CCK after gastrectomy].

Postgastrectomy cholelithiasis has become a problem and biliary tract dyskinesia has been cited as an etiologic factor. CCK is the most important gut hormone with respect to biliary tract function, so we conducted an experimental study of postgastrectomy gallbladder function and CCK levels which gave the following results: 1. Although postprandial gallbladder contraction for the most part occurred in response to endogenous CCK, another mechanism (the gastro-cholecystic reflex) seemed to be responsible for some of them. 2. The postgastrectomy decrease in postprandial gallbladder contraction appeared to be due to disappearance of this gastro-cholecystic reflex. 3. Gallbladder contraction occurred in association with postprandial CCK secretion following total gastrectomy and Roux-en-Y reconstruction, but the altered food passage route caused changes in the dynamics of CCK secretion, and this is believed to have had an influence on the gallbladder contractile response.

Animals↗
PubMed1990

Cholecystokinin-induced contraction of opossum sphincter of Oddi. Mechanism of action.

In this study, we evaluated the mechanism of action whereby cholecystokinin increases spike-burst rate of the opossum sphincter of Oddi (SO). Each spike burst corresponds to a peristaltic SO contraction. Two types of animal preparations were evaluated: (1) awake chronic animal preparations and (2) anesthetized animals. A total of 19 chronic animals were prepared by implantation of electrodes on the SO, gastric antrum, duodenum, and jejunum. SO spike-burst rate was stimulated by intravenous infusion of CCK-OP (10 ng/kg/min), feeding, or intraduodenal infusion of fat-containing nutrient. Each stimulus was begun 20 min after cessation of phase III duodenal MMC activity and caused an increase in SO spike-burst rate from about 2 to 6/min that lasted for less than or equal to 1 hr. Such increases were antagonized substantially by hexamethonium, atropine, or methysergide. The CCK antagonist, L364718, antagonized the excitatory SO response to CCK-OP infusion or intraduodenal infusion of fat-containing nutrient (Isocal) but did not antagonize the response to feeding; CR1409 had no antagonistic effect on SO response to any of the three types of stimuli. In the acute studies in anesthetized animals, an intravenous bolus dose of CCK-OP (800 ng/kg) caused a substantial increase in SO spike-burst rate that was antagonized by CR1409 but not by atropine, hexamethonium, methysergide, L364718, or TTX.(ABSTRACT TRUNCATED AT 250 WORDS)

Ampulla of Vater↗
PubMed1990

Mechanism of cholecystokinin-induced contraction of the opossum gallbladder.

The present study evaluated the mechanism of cholecystokinin-induced gallbladder contraction in awake opossums. Each of 19 chronic animal preparations had an indwelling gallbladder cannula for monitoring changes in gallbladder volume and a jugular catheter for administration of cholecystokinin octapeptide and drugs. An intraduodenal catheter allowed intraduodenal infusion of Isocal (Mead Johnson Laboratories, Evansville, Ind.). Bipolar electrodes in the stomach, duodenum, and jejunum enabled monitoring of the duodenal migratory myoelectric complex cycle. One-hour infusions of cholecystokinin octapeptide (10 ng/kg/min), intraduodenal Isocal (0.4 ml/min), or feeding were started 20 min after cessation of phase 3 duodenal migratory myoelectric complex activity. Bolus intravenous doses of potential pharmacological antagonists were given 10 min before and 20 min after the onset of cholecystokinin octapeptide infusion, Isocal infusion, or feeding. Each test challenge induced about 60% gallbladder emptying at 30 min and 70% at 60 min. Cholecystokinin octapeptide-induced gallbladder emptying was converted to filling by hexamethonium and nearly abolished by atropine. Similar results were obtained for gallbladder emptying induced by feeding or duodenal infusion of Isocal. Phentolamine caused a modest decrease of cholecystokinin octapeptide-induced gallbladder contraction at 30 min, whereas postprandial or Isocal-induced gallbladder contraction was unaffected. Cholecystokinin octapeptide-induced gallbladder contraction was not affected by pirenzepine, 4-diphenylacetoxy-N-methylpiperidine methiodide, prazosin, pyrilamine, cimetidine, methysergide, naloxone, or propranolol. In acute studies of anesthetized animals, gallbladder contraction induced by a D100 intravenous bolus of cholecystokinin octapeptide (800 ng/kg) was not antagonized by hexamethonium, atropine, or tetrodotoxin. It is concluded (a) that cholecystokinin-induced physiologic contraction of the opossum gallbladder occurs through neural mechanisms rather than by a direct action of cholecystokinin on gallbladder smooth muscle, and (b) that studies using pharmacologic bolus doses of cholecystokinin octapeptide and tetrodotoxin indicate that cholecystokinin receptors exist on the gallbladder smooth muscle which do not seem to have any physiological role in gallbladder emptying.

Animals↗
PubMed1990

[Clinical and pathological studies on two patients with adult-onset nemaline myopathy].

Clinical and pathological findings of two patients, a 44-year-old male and a 54-year-old female, with adult-onset nemaline myopathy were described. Both patients showed normal motor development through their childhood; Patient 1 ran fast and was involved in powerful heavy labor until the age of 40, and Patient 2 was in good health until 49, when they began to have progressive muscle weakness. They had no family history of neuromuscular diseases. On neurological examination, they had moderate muscle weakness and atrophy in their limb-girdle and paravertebral muscles. Because paravertebral and neck muscles were preferentially involved, they had difficulty in holding the head straight up. They stood in a lordotic posture. They had neither high-arched palate nor facio-skeletal abnormalities which were common findings in congenital nemaline myopathy. Serum enzymes derived from muscle were normal and needle electromyography showed myogenic and neurogenic changes in both patients. On CT scan of the skeletal muscles, the paravertebral muscles were markedly decreased in density suggesting advanced fat tissue replacement in large areas. In patient 2 who was in more advanced stage, the quadriceps femoris, hamstrings and soleus muscles also showed the similar CT findings. Light microscopic examination of biopsied biceps brachii (Patient 1) and quadriceps femoris (Patient 2) demonstrated abundant rod-like structures in the majority of type 1 fibers. In both patients, there was a marked variation in fiber size. Type 1 fibers were atrophic and type 2C fibers increased in number.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Peripheral nerve pathological findings in familial amyloid polyneuropathy: a correlative study of proximal sciatic nerve and sural nerve lesions.

To analyze the peripheral nerve pathological abnormalities in familial amyloid polyneuropathy, a correlative pathological study was carried out on the spinal nerve roots, proximal sciatic nerves, sural nerves, and brachial plexuses from 3 patients with the disease in Japan. The spinal nerve roots appeared to be unaffected except for amyloid deposition on the epineurium. In sciatic nerves and brachial plexuses the nerve lesions had a multifocal distribution, showing prominent interstitial edema in the endoneurium frequently adjacent to deposits of amyloid; in these regions the nerve fibers were severely depleted. A teased-fiber study revealed that segmental demyelination was the predominant type of nerve fiber abnormality. However, these findings were not seen in the sural nerves; instead a diffuse fiber loss with axonal degeneration was observed. It is suggested that multifocal lesions in the proximal portions of the long extremity nerves could summate distally to produce a symmetrical polyneuropathy in the disease. In addition to a space-occupying effect of amyloid deposits in the endoneurium, severe endoneurial edema associated with amyloid deposition in blood vessels and the endoneurial interstitium may induce ischemia in nerve fibers, thus causing the progressive polyneuropathy in this disorder.

Adult↗
PubMed1987

Hereditary generalized amyloidosis with polyneuropathy. Clinicopathological study of 65 Japanese patients.

A clinicopathological study was made on 65 patients from a small area of Nagano Prefecture, Japan, with hereditary generalized amyloidosis with polyneuropathy to clarify the clinical variety of the disease. Forty-five patients from Ogawa village showed similar clinical features. The age of onset ranged widely from 16 to 62 years. The main neurological manifestations were polyneuropathy starting in the legs and autonomic dysfunction. Lower cranial nerves were also affected in the advanced stages. Severe cardiac and renal involvement was uncommon. All these clinical features are consistent with type I familial amyloid polyneuropathy (FAP). The remaining 20 patients from five unrelated kinships showed unique clinical pictures. Two families from Ogawa village had type I FAP, but 4 out of the 5 affected patients showed marked nephropathy with heavy proteinuria from an early stage. Of the three other families, one, with 10 patients, was notable for the involvement of the central nervous system. Most of the patients showed cerebellar ataxia and pyramidal tract signs in addition to a sensorimotor and autonomic peripheral neuropathy. Another family had 2 siblings who had severe amyloid heart disease from the onset and developed polyneuropathy with autonomic features at an advanced stage. In the third family, onset occurred in the sixth decade in all 3 patients and the course was mild in 2, although the clinical features were those of typical type I FAP. Immunohistochemical study revealed that the amyloid fibril proteins in the patients with all four unusual clinical phenotypes were related to plasma prealbumin. The most common form of hereditary generalized amyloidosis in Japan is type I FAP, but the disease shows considerable variety in the age of onset and involves more systemic organs than previously recognized. The newly recognized clinical forms of hereditary generalized amyloidosis with severe amyloid heart disease or central nervous dysfunction indicate clinical heterogeneity of hereditary amyloidosis with polyneuropathy.

Adolescent↗
PubMed1985

Tetrahymena thermophila glutamine tRNA and its gene that corresponds to UAA termination codon.

Nucleotide sequence analysis of one of several tRNA genes cloned from Tetrahymena thermophila macronuclear DNA indicated that it corresponds to a tRNA species having TTA as anticodon. Subsequently, the tRNA species corresponding to that gene was isolated and its nucleotide sequence was determined by post-labeling techniques. The nucleotide sequence was found to be pG-G-U-U-C-C-A-U-A-m2G-U-A-psi-A-G-D-G-G-D- D-A-G-U-A-C-U-G-G-G-G-A-Cm-U-Um-U-A-i6A-A-psi-C-C-C-U-U-G-A-C- m5C-U-G-G-G-U-psi-C-G-m1A-A-U-C-C-C-A-G-U-G-G-G-A-C-C-U-C-C-AOH. This tRNA sequence exactly matched the DNA sequence of the corresponding tRNA gene. The first position of anticodon is 2'-O-methyluridine (Um), forming UmUA as the anticodon, which presumably recognizes the ochre termination codon UAA. This tRNA species is aminoacylated with glutamine by a Tetrahymena crude aminoacyl tRNA synthetase fraction, suggesting that ochre termination codon is used as a glutamine codon during cytoplasmic protein synthesis in Tetrahymena.

Animals↗