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Biomedical subjects

H Nakai

Publications and source records attributed to H Nakai.

At least 73 records · Page 4Linked to original sources
PubMed1999

[Effects of Helicobacter pylori eradication therapy on the healing process of peptic ulcers].

The advent of H2-receptor antagonists (H2RA) and proton pump inhibitors (PPI) has particularly revolutionized the treatment of peptic ulcer disease. Most cases can now be successfully controlled by medical treatment with H2RA and PPI, but a high rate of ulcer recurrence remains an important problem. The quality of ulcer healing (QOUH) has therefore received increasing attention, and various investigators have attempted to define the conditions required for nonrecurrence. Ulcer scars with a good QOUH are considered to have a very low risk of recurrence. Recent studies have confirmed that recurrence of peptic ulcer can be suppressed markedly by eradication of Helicobacter pylori (H. p). Moreover, various types of endoscopic examinations (conventional observation, dye-contrast endoscopy, magnifying endoscopy, endoscopic ultrasonography, pharmacoendoscopy) have confirmed that the QOUH after eradication of H. p is better than that after conventional anti-ulcer therapy. H. p eradication therapy may become treatment of first choice for peptic ulcers.

Anti-Bacterial Agents↗
PubMed1999

Identification of the binding site for an alloantibody to von Willebrand factor which inhibits binding to glycoprotein Ib within the amino-terminal region flanking the A1 domain.

An alloantibody to von Willebrand factor (vWF) which developed in a Japanese boy with type 3 von Willebrand disease has been characterized. The antibody was non-precipitating IgG and the main subclasses were IgG2 and IgG4. The antibody inhibited completely ristocetin-induced platelet aggregation (RIPA) and high shear stress-induced platelet aggregation (SIPA). Its predominant inhibitory role was focused, therefore, on the interaction between vWF and platelet gycoprotein Ib. The antibody reacted with a 52/48 kDa tryptic fragment of vWF (residues 449-728). No reaction was seen, however, with either a 39/34 kDa dispase fragment (480-718) or a recombinant vWF fragment (residues 465-728). These findings suggested that the essential epitope resided in the amino-terminal flanking region of the Al domain. We synthesized overlapping peptides corresponding to the region containing D3/A1 boundary. A peptide, residues 458-472, bound to the antibody and dose-dependently blocked the antibody binding to the 52/48 kDa fragment. The same peptide neutralized the inhibitory effect of the alloantibody on SIPA. The data are consistent with the presence of an epitope within residues 458-472 which reacted with the 52/48 kDa fragment. Furthermore, the specific component of the antibody, directed against residues 458-472, blocked vWF binding to GPIb in absence of exogenous agonist. Our results suggest that the region flanking the Al domain plays an important role in regulating vWF binding to GPIb.

Antibody Specificity↗
PubMed1999

[A case of a traumatic anterior cerebral artery aneurysm following the penetration of the skull base by an iron rod].

A 61-year-old male fell from a position 1 m high when building a house. An iron rod, which protruded upward from a solid base in cement, penetrated this patient's neck 15 cm to the head and was successfully extracted by himself. On admission, he complained of headache and vomiting. General examination disclosed nasal bleeding, intraoral bleeding, and L figured skin laceration in the left side of his neck at the level of the thyroid cartilage. Mild disorientation (JCS2) was noted. Otolaryngological examination disclosed hyperemia on the left side of the vocal cord as well as at the dome of the superior pharynx. Plain skull film disclosed pneumocephalus and that a piece of bone fragment of the planum sphenoidale had penetrated the brain. CT demonstrated air in the subarachnoid space, ventricular hemorrhage, intracerebral hematoma in the right frontal lobe, and subarachnoid hemorrhage in the anterior interhemispheric fissure. CAG detected neither cerebral vascular abnormalities nor cerebral aneurysm. While staying in our department, he developed mild fever and CSF rhinorrhea. The diagnosis of bacterial meningitis was made from the CSF finding and was well controlled with conservative therapy. CSF rhinorrhea stopped spontaneously with conservative treatment. Sagittal MRI continuously demonstrated contusional hematoma in the base of the right frontal lobe just above the fractured planum sphenoidale and genu of the corpus callosum following the course of the intracranially invading iron rod. The right CAG on Day 10 demonstrated vasospasm on the A1 and a 1 cm sized saccular cerebral aneurysm at the proximal right fronto-polar artery. CAG on Day 17 again showed the persistent presence of the aneurysm. For the purpose of preventing delayed rupture of the aneurysm, radical surgical treatment was planned. Microsurgical dissection disclosed that the aneurysm was located just behind the elevated fracture of the planum sphenoidale. Severe arachnoid adhesion was noted around the aneurysm. The aneurysm was successfully clipped with preservation of the parent artery without inducing new neurological deficits. From the general, otolaryngological, neuroradiological, and operative findings, this aneurysm was diagnosed as a traumatic cerebral artery aneurysm following the penetration of the skull base by the iron rod. The CAG performed at 8 months postoperatively demonstrated the patency of the parent artery and that there was no recurrence of the aneurysm. An unusual case of a traumatic cerebral artery aneurysm following the penetration of the skull base by an iron rod was thus reported.

Accidents, Occupational↗
PubMed1999

Renal cell carcinoma in children: experience at a single institution in Japan.

PURPOSE: We analyzed the presentation, treatment and survival of 4 children with renal cell carcinoma. MATERIALS AND METHODS: We retrospectively reviewed the pathological and hospital records of 4 Japanese children diagnosed with renal cell carcinoma at our hospital from 1970 to 1998. RESULTS: In the 1 boy and 3 girls with an average age of 8 years 7 months at diagnosis the most common presenting complaints were gross hematuria in 75% and a palpable abdominal mass in 50%. Computerized tomography revealed characteristic calcification within the tumor in 3 of the 4 patients (75%). In the remaining case the lesion had high density areas with microcalcification, as confirmed by histopathological study. In 2 patients with regional lymph node metastasis calcification was also observed in the metastatic lesions. Disease was stages I to III in 1, 1 and 2 patients, respectively. All patients underwent transabdominal nephrectomy with regional lymphadenectomy. One patient with stage I disease had multiple metastases 15 months later and died of disease 55 months postoperatively. However, the remaining 3 patients received adjuvant interferon therapy and they are without evidence of recurrence a mean of 51.3 months postoperatively. CONCLUSIONS: Calcification within the tumor and/or metastatic lesions or high density areas in the tumor on screening computerized tomography are characteristic findings suggestive of pediatric renal cell carcinoma. Adjuvant therapy with interferon may provide some benefit in select pediatric patients. Further studies of a larger number of pediatric renal cell carcinoma cases may be necessary to establish the optimal diagnostic and therapeutic regimen.

Carcinoma, Renal Cell↗
PubMed1999

Surgical management of arteriosclerotic coronary artery aneurysm.

A 60-year-old man suffered antero-septal myocardial infarction at the age of 56. Coronary angiography demonstrated total occlusion of the left anterior descending artery and a large saccular aneurysm of the right coronary artery. Diffuse coronary ectasia was also shown in the right coronary artery adjacent to the aneurysm. Despite anticoagulant therapy, the aneurysm formed a thrombus and developed coronary artery stenosis distal to the aneurysm. Ligation of the aneurysm and in situ gastroepiploic artery grafting were performed. Sudden heart failure was developed during skin closure. As this condition was considered to be graft hypoperfusion, supplemental saphenous vein grafting was placed. Ligation is a simple, reliable technique to prevent future complications for a large saccular right coronary artery aneurysm, however, gastroepiploic artery might be an inappropriate bypass conduit for the ligated coronary artery with diffuse ectasia.

Arteries↗
PubMed1998

Adeno-associated viral vector-mediated gene transfer of human blood coagulation factor IX into mouse liver.

Recombinant adeno-associated virus vectors (AAV) were prepared in high titer (10(12) to 10(13) particles/mL) for the expression of human factor IX after in vivo transduction of murine hepatocytes. Injection of AAV-CMV-F.IX (expression from the human cytomegalovirus IE enhancer/promoter) into the portal vein of adult mice resulted in no detectable human factor IX in plasma, but in mice injected intravenously as newborns with the same vector, expression was initially 55 to 110 ng/mL. The expression in the liver was mostly transient, and plasma levels decreased to undetectable levels within 5 weeks. However, long-term expression of human F.IX was detected by immunofluorescence staining in 0.25% of hepatocytes 8 to 10 months postinjection. The loss of expression was likely caused by suppression of the CMV promoter, because polymerase chain reaction data showed no substantial loss of vector DNA in mouse liver. A second vector in which F.IX expression was controlled by the human EF1alpha promoter was constructed and injected into the portal vein of adult C57BL/6 mice at a dose of 6.3 x 10(10) particles. This resulted in therapeutic plasma levels (200 to 320 ng/mL) for a period of at least 6 months, whereas no human F.IX was detected in plasma of mice injected with AAV-CMV-F.IX. Doses of AAV-EF1alpha-F. IX of 2.7 x 10(11) particles resulted in plasma levels of 700 to 3, 200 ng/mL. Liver-derived expression of human F.IX from the AAV-EF1alpha-F.IX vector was confirmed by immunofluorescence staining. We conclude that recombinant AAV can efficiently transduce hepatocytes and direct stable expression of an F.IX transgene in mouse liver, but sustained expression is critically dependent on the choice of promoter.

Adult↗
PubMed1998

The role of platelet von Willebrand factor in the binding of factor VIII to activated platelets.

Factor VIII binds to activated platelets and contributes to the tenase complex assembled on the platelet membrane surface. We have examined the role of platelet von Willebrand factor in the binding of factor VIII to platelets using a platelet captured enzyme-linked immunosorbent assay. Purified factor VIII bound to activated normal platelets in a dose dependent manner. Factor VIII also bound to platelets obtained from a patient with Type 2N von Willebrand disease, although in this case the binding was reduced to approximately 50% of that seen with control platelets. Furthermore, factor VIII bound to Type 3 von Willebrand disease platelets in the absence of detectable von Willebrand factor. In this instance the binding reaction appeared to be approximately 30% of that seen with the same number of normal platelets. An anti-A3 domain monoclonal antibody, NMC-VIII/10, which recognizes the amino-terminal acidic region of the factor VIII light chain, and an anti-C2 domain monoclonal antibody, NMC-VIII/5, which also moderates the binding of factor VIII to phosphatidylserine, inhibited the association between factor VIII and platelets. Inhibition was more remarkable with NMC-VIII/5 than with NMC-VIII/ 10 but not complete. The findings suggest that the binding of factor VIII to activated platelets is not based on a single ligand-receptor relationship, although a predominant role exists for the platelet von Willebrand factor. Furthermore, both the amino-terminal acidic region of the A3 domain and the C2 domain participate in the binding of factor VIII to activated platelets.

Binding Sites↗
PubMed1998

Asymmetrical changes in the fodrin alpha subunit in the superior temporal cortices in schizophrenia.

BACKGROUND: We examined possible abnormalities in neural structural proteins that may underlie morphometric changes reported in the left superior temporal cortices (Brodmann's area 22) of schizophrenics. METHODS: Particulate proteins of the superior temporal cortices taken at autopsy from 11 schizophrenic and 9 control brains were fractionated by gel electrophoresis. Target proteins, identified by reading their amino acid sequences, were immunoquantified using the specific antibody. RESULTS: Amino acid sequences of the 150-kDa proteins on sodium dodecyl sulfate/polyacrylamide gel electrophoresis, which were significantly increased on the left side of schizophrenic superior temporal cortices, revealed that they were proteolytic fragments of the alpha subunit of fodrin, a major cytoskeletal protein underlying the plasma membrane. Immunoquantification using the specific antibodies against alpha and beta subunits of fodrin indicated that there exist concomitant decreases in the full-length 240-kDa form and increases in the 150-kDa form of alpha-fodrin with no changes of the 235-kDa form of beta-fodrin in the left superior temporal cortices of the schizophrenic brains. CONCLUSIONS: The findings may be a possible molecular basis for linking morphometric changes to neurochemical pathophysiology in schizophrenia.

Aged↗
PubMed1998

Versatile action of Escherichia coli ClpXP as protease or molecular chaperone for bacteriophage Mu transposition.

The molecular chaperone ClpX of Escherichia coli plays two distinct functions for bacteriophage Mu DNA replication by transposition. As specificity component of a chaperone-linked protease, it recognizes the Mu immunity repressor for degradation by the peptidase component ClpP, thus derepressing Mu transposition functions. After strand exchange has been promoted by MuA transposase, ClpX alone can alter the conformation of the transpososome (the complex of MuA with Mu ends), and the remodeled MuA promotes transition to replisome assembly. Although ClpXP can degrade MuA, the presence of both ClpP and ClpX in the reconstituted transposition system did not destroy MuA essential for initiation of DNA replication by specific host replication enzymes. Levels of ClpXP needed to overcome inhibition by the repressor did not prevent MuA from promoting strand transfer, and ClpP stimulated alteration of the transpososome by ClpX. Apparently intact MuA was still present in the resulting transpososome, promoting initiation of Mu DNA replication by specific replication enzymes. The results indicate that ClpXP can discriminate repressor and MuA in the transpososome as substrates of the protease or the molecular chaperone alone, degrading repressor while remodeling MuA for its next critical function.

ATPases Associated with Diverse Cellular Activitie↗
PubMed1998

Isotype-specific G protein abnormalities in the left superior temporal cortex and limbic structures of patients with chronic schizophrenia.

BACKGROUND: The potential role of signal transducing guanine nucleotide-binding regulatory protein (G protein) in schizophrenia is largely unknown. METHODS: We immunoquantified isotypes of G protein using specific antisera against alpha and beta subunits of G protein in the superior temporal, prefrontal, and entorhinal cortices as well as the nucleus accumbens and amygdala of postmortem brains from 19 schizophrenic and 28 control subjects. RESULTS: In the left hemisphere of schizophrenics, the amount of Gi alpha, Go alpha, and Gq alpha but not that of Gs alpha or G beta decreased in the superior temporal cortex by 27%, 27%, and 16%, respectively, as compared with the values in ipsilateral controls; the amount of any G protein isotype in the prefrontal and entorhinal cortices was not changed. In the nucleus accumbens and amygdala, the paranoid type schizophrenics showed a smaller amount of Gi alpha and Go alpha than the disorganized type schizophrenics. In the right superior temporal cortex, the isotype amount did not differ between the schizophrenic and control groups. CONCLUSIONS: The decreased Gq alpha immunoreactivity in the schizophrenic left superior temporal cortex may reflect the down-regulation of Gq alpha, resulting from chronic stimulation of Gq alpha-coupled receptors, while the decreased Gi alpha and Go alpha in the nucleus accumbens and amygdala of paranoid type schizophrenics may be related to the dopaminergic hyperactivity via dopamine D2 receptors.

Aged↗
PubMed1998

Successful laparoscopic cholecystectomy in a child with upper transverse scarring: report of a case.

Laparoscopic cholecystectomy (LC) was safely performed for cholelithiasis in a 4-year-old boy who had a long transverse operative scar in the upper abdomen as a result of intestinal surgery performed during the neonatal period. The adhesions beneath the scar were sharply divided and sometimes coagulated, and additional working ports were subsequently placed as the adhesiolysis proceeded. LC was performed in the usual fashion using 5-mm titanium clips, and his postoperative course was uneventful. This case report serves to demonstrate that laparoscopic surgery is feasible even for pediatric patients who have undergone previous major intraabdominal surgery.

Child, Preschool↗
PubMed1998

The influence of compressive loading on growth of cartilage of the mandibular condyle in vitro.

The purpose of this study was to clarify the change in mandibular condyles under compressive loading. An organ-culture system of fetal rat mandibular condyles was used, and mechanical loading was generated by compressing the gas phase within a closed chamber. After the culture period, with compressive loading, type I collagen and fibronectin were observed in the lower half of the hypertrophic chondrocyte layer in the mandibular condyles; in contrast, without compressive loading, there was no such reaction. The size of the condyle was not increased by compressive loading. These results suggest that intermittent compressive loading could induce type I collagen and fibronectin production by chondrocytes.

Animals↗
PubMed1998

Acquired umbilical fistula after repair of inguinal hernia: a case report.

A 2-year, 9-month-old boy had an umbilical fistula after repair of an inguinal hernia at 8 months of age. Fistulography findings showed a duct running from the umbilicus toward the inguinal wound. Pathological finding of the surgically removed fistula demonstrated granulomatous tissues containing silk ligature. Acquired umbilical fistula is a rare complication of inguinal herniorrhaphy. Its clinical details as well as a review of the previously reported four cases are presented.

Child, Preschool↗
PubMed1998

Temporary arterial occlusion during anterior communicating or anterior cerebral artery aneurysm operation under tibial nerve somatosensory evoked potential monitoring.

BACKGROUND: Median nerve somatosensory evoked potentials (SEP) have been used as an indicator of cerebral ischemia in the territory of the middle cerebral artery. This study was designed to examine whether tibial nerve SEPs are a useful technique for detecting ischemia in the territory of the anterior cerebral artery (ACA) during aneurysm surgery. METHODS: Tibial nerve SEP monitoring was employed in 15 patients who underwent temporary arterial occlusion during surgery for aneurysms of the anterior communicating artery (ACoA) or ACA. To evaluate tibial nerve SEPs, the data after anesthesia induction but before the start of surgery were used as the control and a more than 50% decrease in the amplitude of P40-N50 was regarded as a significant change. RESULTS: Changes in SEP were recognized in 11 of these 15 patients. Unilateral A1 occlusion resulted in SEP changes in 4/7, while bilateral A1 interruption caused changes in 6/8 of the patient group. The allowable duration of interruption of the ACA cannot be determined by A1 dominance or the extent of development of the ACoA that can be recognized by angiography. The significance of the collateral circulation via the leptomeninges was indicated. Following the release of the occlusion, SEPs were restored to the control level in all patients and no new motor deficits were found. CONCLUSIONS: It was concluded that tibial nerve SEP monitoring is a useful system to determine the extent of cerebral ischemia of the ACA territory during temporary arterial occlusion associated with surgery for aneurysms involving the ACA system.

Aged↗
PubMed1998

New orally active enkephalinase inhibitors: their synthesis, biological activity, and analgesic properties.

A series of (4S)-4-[(2S)-benzyl-3-mercaptopropionylamino]-4-(N-phenylcarbamoyl )-butyric acids has been identified as potent systemically active enkephalinase inhibitors. Structure-activity relationships (SAR) are discussed. Further chemical modification of the inhibitors was carried out in order to identify the inhibitors which are orally active in an animal model. Compounds of particular interest are the prodrug-like analogues, including 5b (ONO-9902). Their analgesic effects after oral administration were evaluated.

Administration, Oral↗