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Biomedical subjects

T Yamagami

Publications and source records attributed to T Yamagami.

At least 127 records · Page 7Linked to original sources
PubMed1994

Clinicopathological study of proliferating cell nuclear antigen (PCNA) of hepatocytes in primary biliary cirrhosis.

The DNA synthesis activities of hepatocytes in primary biliary cirrhosis (PBC) and other chronic liver diseases and control subjects were examined by staining proliferating cell nuclear antigen (PCNA) with anti-PCNA monoclonal antibody. The number of PCNA-positive cells (PCNA value) was significantly higher in PBC (375 +/- 281 parts per thousand; ppt) than in other chronic liver diseases, i.e., chronic hepatitis (95 +/- 83 ppt), liver cirrhosis (72 +/- 71 ppt), and alcoholic liver disease (73 +/- 56 ppt), and in control subjects (11 +/- 14 ppt). The PCNA value of PBC in stages I-III of Scheuer's classification was remarkably high, while in stage IV it was low. Even in identical, Scheuer's stages, the PCNA value of PBC was higher in patients who were not given ursodeoxycholic acid (UDCA) than in those who received UDCA. In identical patients, the PCNA value was lowered significantly after UDCA treatment. It was concluded that the DNA synthesis activity of PBC in stages I-III was accelerated and that UDCA can alleviate the abnormality in DNA synthesis activity.

Chronic Disease↗
PubMed1994

An adult patient with cerebellar ganglioglioma.

We encountered a very rare patient with cerebellar ganglioglioma. To our knowledge, there are 17 reported patients with this disease, of whom ours (a 53-year-old male) was the oldest. The tumor was totally resected, but radiotherapy was also performed to prevent recurrence. He is completely symptom-free 9 months after operation.

Cerebellar Neoplasms↗
PubMed1994

Brachial plexus injury with cough attack: case report.

Cough attacks elicited by movement of the neck and right arm are reported in a patient who had sustained several shoulder injuries and who had an anterior scalenectomy. The coughing was accompanied by weakness in the right upper limb. At exploration, the phrenic nerve was found adhered to the brachial plexus. The cough attacks disappeared, and the weakness of the right upper limb improved somewhat after lysis of the adhesions between the phrenic nerve and the plexus and after external neurolysis of the upper, middle, and lower trunks. Postoperatively, the patient could elevate his right arm without coughing.

Brachial Plexus↗
PubMed1994

The complete amino acid sequence of chitinase-a from the seeds of rye (Secale cereal).

The complete amino acid sequence of rye seed chitinase-a (RSC-a) has been analyzed. RSC-a was cleaved with cyanogen bromide and the resulting three fragments, CB1, CB2, and CB3, were separated by gel filtration. The amino acids of the N-terminal fragment CB1 were sequenced by analyzing the peptides produced by digestion with trypsin, lysylendopeptidase, or pepsin of reduced S-carboxymethylated or S-aminoethylated CB1. The sequences of fragments CB2 and CB3 were established by sequencing the tryptic peptides from reduced S-carboxymethylated CB2 and CB3, and by aligning them with the sequence of rye seed chitinase-c (RSC-c) to maximize sequence homology. The complete amino acid sequence of RSC-a was established by connecting these three fragments. RSC-a consists of 302 amino acid residues including hydroxyproline residues, and has a molecular mass of 31,722 Da. RSC-a is basic protein with a cysteine-rich amino terminal domain, indicating that this enzyme belongs to class I chitinases. The amino acid sequence of RSC-a showed that the sequence from Gly60 to C-terminal Ala302 in this enzyme corresponds to that of RSC-c belonging to class II chitinases with 92% identity, and that RSC-a has high similarity to other plant class I chitinases but a longer hinge region and an extra disulfide bond.

Amino Acid Sequence↗
PubMed1994

Application of oriented poly-L-lactide screws for experimental Salter-Harris type 4 fracture in distal femoral condyle of the dog.

The clinical usefulness of biodegradable oriented poly-L-lactide (PLLA) screws for experimental Salter-Harris type 4 fracture in the distal femoral condyle of dogs was evaluated. Bony union of the osteotomized fragment of the condyle was almost completed radiographically and histologically within 1 to 2 months after surgery, suggesting that PLLA screws maintained strength long enough to fix the fragment until bone healing. At 4 to 6 months after surgery, minute fissures were histologically confirmed on the surface of the screw thread, suggesting the early stage of biodegradation and absorption of the polymer. During the observational period, no significant difference between the treated femur and the contralateral non-treated femur in either total femoral length or maximum condyle width was observed, indicating no growth disturbance in the treated femur. From these results it was concluded that the PLLA screw might be an ideal implant for the reduction and fixation of epiphyseal plate fractures such as Salter-Harris type 3 or type 4 fractures.

Animals↗
PubMed1994

Chloride-dependent potentials and their effects on firing pattern in guinea-pig cingulate cortical neurons.

Intracellular recordings were made from pyramidal neurons in the anterior cingulate cortex layer V of the guinea-pig slice preparation. An oscillation in membrane potential occurred when the membrane was depolarized to a subthreshold level (e.g. -60 mV), and the oscillation triggered repetitive firing. The frequency of the spontaneous firing varied with the membrane potential: frequencies were 2.9 +/- 1.4, 6 +/- 1, 13 +/- 3, and 17 +/- 3 Hz at the membrane potentials of -60, -58, -55, and -40 mV, respectively. Bicuculline (500 nM to 10 microM) increased the firing rate when the membrane potential was kept around threshold level by DC current injection. 2-Hydroxysaclofen and low Cl- (43 mM) also increased the firing rate, but 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulphonate (SITS, 250 microM) did not change the firing rate. Strychnine (1 to 3 microM) had no effect on the spontaneous firing. These results suggest that the firing frequency of cingulate pyramidal neurons is modulated by GABA tonically released by interneurons.

6-Cyano-7-nitroquinoxaline-2,3-dione↗
PubMed1994

[Carpal tunnel syndrome: clinical experience of 61 cases].

Carpal tunnel syndrome (CTS) is the most frequent entrapment neuropathy. Appropriate diagnosis and therapy contribute to obtaining good results. We performed carpal tunnel release in 61 patients including 8 cases with chronic renal failure. They included 18 males and 43 females. Age distribution was from 28 to 76 years of age among the males, and from 29 to 82 years of age among the female patients. Bilateral operations were performed in 13 cases (male 5, female 8). Operations were carried out with local anesthesia in all cases except one. The skin incision was about 5 cm on the palmar skin. Hypertrophy of the transverse carpal ligament was found in all cases, with a thickness of 4 mm on the average. Usually, the ligament was as hard as gum in consistency. There were also hypertrophy of the subcutaneous connective tissue and palmar aponeurosis or aberrant muscle in some cases. In CTS following long-term hemodialysis for chronic renal failure, the ligament was very hard and appeared to be partly calcified. All patients improved clinically after the operation. We should understand the characteristic clinical symptoms and signs of CTS. Clinical worsening was prominent at night and/or early in the morning. Definite diagnosis was performed by electrophysiological means. Operative indications are 1) cases whose daily activities are disturbed due to severe symptoms with progressive aggravation, 2) cases with muscle weakness in the distribution of the median nerve, 3) cases with thenar atrophy, 4) cases which, electrophysiologically, are suspected of demyelination of the median nerve. As there were many unpredictable anomalies and variations among the lesions, correct decompression of the median nerve under direct vision is necessary during surgery.

Adult↗
PubMed1993

Effects of laminectomy and retained extradural foreign body on cauda equina adhesion.

The histologic effects of posterior lumbar surgery and retained extradural foreign bodies on the cauda equina were investigated in rats over time. The following four groups of rats were provided: Group 1, sham operation (laminar exposure alone); Group 2, laminectomy alone; Group 3, laminectomy with retained extradural silk thread; Group 4, laminectomy with extradural kaolin; and the control. Histological study was performed on the transverse sections of laminectomized (L5) and nonlaminectomized (L4) areas. In Group 1, adhesive changes involving the cauda equina, consisting of dilatation of nutrient vessels, and eosinophilic exudative changes between the adhering cauda rootlets were seen the day after surgery, but the fibrinous adhesion was resolved spontaneously in all rats after 1 week without permanent sequelae. In Groups 2 and 3, postoperative adhesion of the cauda equina roots was conspicuous, but it resolved by 6 weeks. In Group 4, obvious adhesion persisted through the 12th week after surgery. Destruction of the myelin sheath and axonal loss of the cauda equina occurred in the first week after surgery in all the experimental groups except in the sham group. The severity and extent of the neural degeneration were mostly parallel to the severity of inflammatory changes in the epidural areas. At the nonlaminectomized area (L4) in each group, the arachnoid and cauda equina tended to congregate the day after surgery, but these changes were all transitory. The severity and persistency of the arachnoiditis and neural degeneration directly corresponded to the magnitude of the inflammation and wound healing processes. This seems to imply that careful surgical intervention with no use of foreign bodies is necessary to reduce postoperative adhesive arachnoiditis.

Animals↗
PubMed1993

Calcification inhibitors in human ligamentum flavum.

To examine the presence of substances which inhibit calcification in human ligamentum flavum, the inhibitory effect of an Na2HPO4 extract of the flavum was determined in terms of the in vitro calcium uptake of the ligamentum flavum matrix. Additionally, grafts of extracted and non-extracted dry ligamentum flavum matrices were transplanted into the dorsal muscles of rats, and calcification in the grafts was examined radiologically and histochemically. In order to determine if component cells of human ligamentum flavum produce calcification inhibitors, ligamentum flavum cells were cultured, and the crystal inhibitor activity of the culture medium was measured by a seed test which used hydroxyapatite as the nucleus of precipitation. The calcification reaction system demonstrated that the ligamentum flavum extract contains an inhibitory factor for calcium uptake by the ligamentum flavum matrix. The seed test revealed that human ligamentum flavum cells produce calcification inhibitor activity.

Adolescent↗
PubMed1993

Cardiostimulatory action of coenzyme Q homologues on cultured myocardial cells and their biochemical mechanisms.

The effect of coenzyme Q (CoQ) homologues on the beating of myocardial cells was investigated in cultured cell sheets from mouse fetuses and quail embryos. Myocardial cell sheets grown in Eagle's minimum essential medium with fetal bovine serum showed very weak and irregular beating when this serum was removed from the medium. However, the depressed beating rate and amplitude recovered almost completely within a few minutes by adding CoQ10 to the medium, and the effect of CoQ10 continued over 1 h. CoQ9 showed a cardiostimulatory effect similar to that of CoQ10, but CoQ8 and CoQ7 showed almost no effect. Short homologues (less than CoQ4) inhibited the beating of cell sheets. The cardiostimulatory effect of CoQ10 was not blocked by atenolol, a selective beta-blocker. In addition, CoQ10 stimulated the formation of ATP, not cAMP. CoQ0 and CoQ3 inhibited beating rates by inhibiting ATP formation. In conclusion, only native CoQ homologues having a nona- or decaprenyl group showed a cardiostimulatory effect on cultured myocardial cells, probably by stimulating mitochondrial ATP formation.

Animals↗
PubMed1993

The scid mutation in mice causes defects in the repair system for both double-strand DNA breaks and DNA cross-links.

The sensitivity of scid fibroblasts established from C.B17-scid/scid fetuses to the DNA-damaging agents bleomycin, neocarzinostatin, mechlorethamine, mitomycin C, methyl methanesulfonate, and ultraviolet light, all of which induce different types of DNA damage, was examined. Scid fibroblasts were 2.8-, 3.7-, and 3.0-fold more sensitive to bleomycin, neocarzinostatin, and mechlorethamine, respectively, than wild-type fibroblasts derived from C.B17-+/+ fetuses. These findings indicate that the scid mutation in mice causes defects in repairing both double-strand DNA breaks and DNA cross-links.

Animals↗
PubMed1993

Cerebral cysticercosis: a case report.

A case of cerebral cysticercosis is reported in a 49-year-old female who presented with headache, nausea, and vomiting. Lumbar CSF showed the findings of mild aseptic meningitis. CT scan revealed an enlargement of the left ambient cistern and a small cystic lesion in the left frontal cortex. MRI demonstrated multilobular cysts in the left ambient cistern with enhancement of their capsules, which compressed and distorted the midbrain. The cysts were surgically excised, and histological examination of the specimen disclosed characteristic features of cysticercus with viable larva. An excellent value of MRI in the diagnosis of intracisternal cysticercosis is emphasized.

Brain Diseases↗
PubMed1993

Structure and expression of the gene encoding rat nonspecific form delta-aminolevulinate synthase.

To understand the regulatory mechanisms controlling the heme biosynthetic pathway in animal liver, RNA blot hybridization analysis was used to examine the developmental stage-specific transcription of the gene encoding nonspecific form delta-aminolevulinate synthase (ALAS-N). The expression of the erythroid-specific delta-aminolevulinate synthase (ALAS-E) mRNA was also studied. The results demonstrated that, while ALAS-E is the key enzyme which supplies large quantities of heme for hemoglobin synthesis in fetal rat liver, ALAS-N functions to supply heme for the cytochrome P-450 system in fetal, newborn, and adult rat liver. ALAS-N was also suggested to work as a housekeeper gene to supply heme for respiratory cytochromes and other hemoproteins in various tissues. The structure and organization of the rat ALAS-N gene were next analyzed to study the molecular mechanisms regulating ALAS-N gene transcription. The ALAS-N gene was found to span more than 14 kb in the rat genome, encompassing eleven exons. The promoter region of the gene was found to contain several potential cis-acting regulatory elements, including motifs matching the TATA box sequence and the nuclear respiratory factor 1 binding sequence. The organization of the rat ALAS-N gene was determined to be quite similar to that of the ALAS-E gene in mouse; the mouse ALAS-E gene consists of eleven exons. This observation suggested that the ancestral gene for ALA synthase in animals was probably composed of eleven exons, and both the ALAS-N and ALAS-E genes were derived from this ancestral gene.

5-Aminolevulinate Synthetase↗
PubMed1993

Purification and structure of rat erythroid-specific delta-aminolevulinate synthase.

The existence of erythroid form delta-aminolevulinate synthase (ALAS-E) was historically a matter of some controversy. To obtain direct evidence for a unique ALAS-E, we have purified ALAS-E to homogeneity for the first time, from rat reticulocyte lysate. The papain digestion method was used at the initial step of the purification to overcome the difficulty which repeatedly hampered earlier attempts to purify ALAS-E. The size of the purified papain-resistant core catalytic domain of ALAS-E was estimated electrophoretically to be 49,000 Da. The pH optimum (7.6) and apparent Km values for the substrates, glycine (6.5 mM) and succinyl-CoA (2 microM), were similar to those of the non-specific form of delta-aminolevulinate synthase (ALAS-N); but, in contrast to ALAS-N, the substrate inhibition by succinyl-CoA was not evident in ALAS-E. We then isolated cDNA and genomic DNA clones encoding rat ALAS-E. By combining the nucleotide sequence information of the cDNA and genomic clones, the rat ALAS-E precursor is predicted to be composed of 587 amino acids with a calculated molecular mass of 64,841 Da. All the peptide sequences determined directly from the purified protein agreed with those predicted from the nucleotide data, demonstrating the existence of ALAS-E. Analysis of the papain-resistant core domain further revealed that it overlaps with the evolutionally conserved segment that has been noticed by sequence alignment analysis of ALA synthases from various species.

5-Aminolevulinate Synthetase↗
PubMed1993

The complete amino acid sequence of chitinase-c from the seeds of rye (Secale cereal).

The complete amino acid sequence of rye seed chitinase-c (RSC-c) has been analyzed. This was done by first sequencing the tryptic peptides from RCm-RSC-c and then connecting them by analyzing the peptides produced by digestions with lysylendopeptidase and Staphylococcus aureus V8 protease of RCm-RSC-c, and by chymotryptic digestion and formic acid cleavage of S. aureus V8 protease peptides. RSC-c consists of 243 amino acid residues and has a molecular mass of 26,093, and has 92% sequence homology with barley seed basic chitinase which lacks a Cys-rich domain. Cys204 is free and six cysteine residues are linked by disulfide bonds between Cys23 and Cys85, Cys97 and Cys105, and Cys223 and Cys236.

Amino Acid Sequence↗
PubMed1993

Purification and some properties of three chitinases from the seeds of rye (Secale cereale).

Three chitinases, designated RSC-a, -b, and -c, were purified from the seeds of rye (Secale cereal) using ammonium sulfate precipitation, CM-cellulose column chromatography, gel filtration on Sephadex G-75, and S-Sepharose column chromatography. RSC-a, -b, and -c are basic proteins having molecular masses of 33 kDa, 26 kDa, and 26 kDa, and isoelectric points of 9.7, 10, and > 10, respectively. RSC-b and -c were found to be homologous proteins having similar amino acid compositions and N-terminal sequences. RSC-a contains more Thr, Ser, Glu, Pro, Gly, and Cys than RSC-b and -c and has a different N-terminal sequence from them. They hydrolyze glycolchitin and colloidal chitin, but not cell walls of Micrococcus lysodeikticus. These enzymes are stable at pH 4-8 and their optimum pHs toward glycolchitin are 5.

Amino Acid Sequence↗
PubMed1993

[Respiratory symptoms in young adulthood in relation to the results of a house dust skin test during childhood--a 20 year follow-up survey].

Beginning in 1972, a survey of respiratory symptoms and allergic skin tests in school children from an agricultural area in the Hokuriku region has been continuing. A higher prevalence of respiratory symptoms in school children with positive house dust skin test has been previously reported. In order to elucidate the relationship between results of a house dust skin test during childhood and manifestation of respiratory symptoms thereafter, an examination of respiratory symptoms was conducted in 1991, of the portion of the 5,334 subjects who participated in the earlier survey during childhood, who still live in the same town after leaving junior high school. The results are as follows: 1) During childhood (school-age), prevalence of respiratory symptoms (subacute cough, wheezing when having a cold, wheezing attack) was higher in the positive skin test group (612 subjects) compared to the negative group (856 subjects). There were no significant differences between the two groups in the prevalence of respiratory symptoms (subacute phlegm, wheezing when not having a cold). 2) In young adulthood, prevalence of respiratory symptoms (subacute cough, subacute phlegm) was higher in the negative skin test group compared to the positive group. There were no significant differences between the two groups in the prevalence of respiratory symptoms (wheezing when not having a cold, wheezing attack). The prevalence of wheezing when having a cold was higher in the positive group compared to the negative group. 3) The paradoxical results in young adulthood was due to a marked decline in the prevalence ratio of the high positive rate skin test group (184 subjects) to the negative skin test group. This suggested a decline in contribution of serum IgE to manifestation of respiratory symptoms in young adulthood compared to childhood, with the result that the positive skin test group had a higher prevalence of respiratory symptoms during childhood, but lower in young adulthood.

Adolescent↗