Search PubMed⌕ Search

Biomedical subjects

H Namba

Publications and source records attributed to H Namba.

At least 181 records · Page 10Linked to original sources
PubMed1991

Lack of evidence for the presence of human immunodeficiency virus type 1-related sequences in patients with Graves' disease.

The pathogenesis of human autoimmune diseases, including Graves' disease, remains to be elucidated. Recently, Ciampolillo et al. proposed that human immunodeficiency virus type 1 (HIV-1)-related retroviruses were involved in Graves' disease. Using Southern blot analysis, they found specific integration of exogenous sequences homologous to HIV-1 gag region in genome DNA of thyrocytes and peripheral blood lymphocytes (PBL) of patients with Graves' disease. In order to test their hypothesis, we examined the presence or the absence of HIV-1 gag-related sequences in Japanese Graves' patients using the polymerase chain reaction (PCR) in addition to Southern blotting. Sets of primer pairs used in PCR were designed to cover the whole span of the HIV-1 gag region. Hybridization was performed in both relaxed and stringent conditions. Our results showed that neither Southern blot hybridization nor PCR gave positive signals in any of the samples examined from Graves' patients. This suggests that HIV-1 or its closely associated viruses are unlikely to be involved in the pathogenesis of Graves' disease in Japan.

Adolescent↗
PubMed1991

Assignment of human porphobilinogen deaminase to 11q24.1----q24.2 by in situ hybridization and gene dosage studies.

In situ hybridization and gene dosage-effect studies were conducted to determine the detailed chromosomal location of the gene encoding human porphobilinogen deaminase (PBGD). Red cell PBGD activity was normal in one patient with monosomy for 11q24.2----qter but was increased 1.5 times in another patient with trisomy for 11q22.2----qter. The cDNA probe for PBGD was found to be specifically hybridized to band 11q24. These results suggest that the gene for PBGD is localized within the region 11q24.1----q24.2.

Abnormalities, Multiple↗
PubMed1991

Solitary polyclonal autonomous thyroid nodule: a rare cause of childhood hyperthyroidism.

Solitary autonomous thyroid tumors are an unusual cause of hyperthyroidism, particularly in childhood. We describe the youngest individual so far reported with this condition, a 22 month child with a large hyperfunctioning thyroid nodule who became overtly hyperthyroid after iodinated contrast administration. The histology of the nodule was compatible with follicular cell hyperplasia. These tumors are often called toxic adenomas, although there is no solid evidence that they are true neoplasms. We examined the clonal composition of the child's thyroid tumor by X-chromosome inactivation analysis, taking advantage of a polymorphism in the X-chromosome gene phosphoglycerate kinase. The tumor consisted of an even mixture of cells containing activated paternal and maternal PGK alleles, indicating that the tumor was polyclonal. Furthermore, the nodule had no structural rearrangements or activating point mutations of ras oncogenes, which are found in up to 50% of solitary monoclonal follicular adenomas. Solitary hot nodules may at least in some cases be secondary to hyperplasia, and not to clonal expansion of an abnormal, mutated cell. This may also explain the relatively low frequency of malignant transformation observed in hyperfunctioning thyroid tumors.

Adenoma↗
PubMed1991

[Physiologically active compounds in the extracts from tochukaso and cultured mycelia of Cordyceps and Isaria].

Tochukaso is a Chinese traditional medicine composed of a fruit body of Cordyceps sinensis and its parasitic host larva. Tochukaso (C. sinensis) and the cultured mycelia of five species of Cordyceps and four species of Isaria were each extracted with hot water and examined for the inotropic effect on guinea-pig right atrium in vitro system. The extracts from C. militaris and I. felina showed a negative inotropic effect to approximately the same extent as that from Tochukaso. These three extracts also showed inhibitory action on twitch response of guinea-pig ileum and aggregation of human blood platelet. It is suggested that these activities are ascribed to the combination of adenosine, 5'-adenosine monophosphate and several other nucleic acid-related compounds, all of which have been shown to be present in the extracts.

Animals↗
PubMed1991

Lack of PTC gene (ret proto-oncogene rearrangement) in human thyroid tumors.

PTC gene, which is derived from the rearranged form of the ret proto-oncogene, was originally discovered in human thyroid papillary carcinomas. This gene has been thought to act as a tumorigenetic factor in thyroid carcinoma, although the action of PTC oncogene products is still unknown. To study the frequency of the PTC gene present in human thyroid carcinomas, we investigated four cell lines derived from thyroid carcinoma and 22 thyroid tumor tissue specimens. The reverse transcriptase-polymerase chain reaction (RT-PCR) method was performed to detect putative PTC mRNA. The presence of the PTC gene in genomic DNA was analyzed by Southern blot hybridization. PTC mRNA was detected by the RT-PCR method in only one papillary carcinoma cell line (TPC-1 cell). Southern gel analysis confirmed the rearrangement of the ret proto-oncogene in this cell line. In the other three cell lines and 22 tumor tissue specimens, however, neither the PTC gene or mRNA was detected. These results demonstrate that the prevalence of the PTC gene in thyroid tumor is low and may not be essential for human thyroid tumorigenesis. That our present results conflict with previous reports may be due to general differences in genetic background among races.

Base Sequence↗
PubMed1991

[Blood flow measurement of brain tumor by 123I-IMP using 3-heads rotating gamma camera SPECT].

Using 3-heads rotating gamma camera SPECT system, regional blood flow was measured from the super-early image obtained 4 to 6 minutes after the intravenous injection of 123I-IMP on 11 patients with various brain tumors. Two cases of olfactory groove meningioma and malignant astrocytoma showed significantly high 123I-IMP uptake by the lesion visualized by MRI compared to the uptake by normal brain cortex on super-early image but 123I-IMP uptake by the tumor decreased on early image. In both cases, blood flow of the tumor measured from super-early image showed values much higher than those of normal brain cortex. It was thought that usual correction method based on early image did not correctly represent the blood flow of the lesion but that the present method based on super-early image could show the increase of blood flow of the tumor.

Adult↗
PubMed1991

[Thyroid carcinoma].

It is now widely accepted that human neoplasms arise as a result of a sequence of mutations affecting the structure of genes involved in growth control. In humans, indirect measurements based on age dependent tumor incidence predict that, on average, the accumulation of 5 to 6 different steps is needed to initiate tumor formation. These mutations do not appear to be random, in that certain neoplasms show prediction for structural aberrations in specific genes. In thyroid tumors, some of gene abnormalities were found. The point mutations of ras oncogenes, predominantly H-ras codon 12, are found in 20-25% of follicular adenomas and papillary carcinomas. Recently, the gene rearrangements of the oncogenes trk and ret were identified in the DNA from papillary carcinomas. About 25% of papillary carcinomas contained an introchromosomal (10q) gene rearrangement involving the tyrosine kinase domain of the ret oncogene with an unknown amino-terminal sequence. The mutations of trk and/or ret were not observed in other thyroid neoplastic phenotypes. In medullary thyroid carcinoma, which is a tumor of the parafollicular, calcitonin-secreting C cell of the thyroid, approximately 20% of patients have autosomal dominant inherited forms. Germ line abnormalities on chromosome 10 are linked to at least one type of genetic medullary thyroid carcinoma (MEN type 2a). In the present time, the person who has the abnormality of gene causing MEN type 2a is able to detect by using DNA marker before the onset of tumor.

Adenocarcinoma↗
PubMed1991

[Mechanical valve thrombosis in the tricuspid position--reoperative management of 2 cases].

Because valve thrombosis occurred after the tricuspid valve replacement with the mechanical valve, we performed replacement of the mechanical valve with the bovine pericardial valve in two cases. Case 1: The patient, at 13 years old, received open-heart surgery to correct infundibular stenosis. At 23 years of age, decortication and tricuspid valve replacement (TVR) with a phi 31 mm Björk-Shiley valve were performed due to constrictive pericarditis and tricuspid regurgitation developed after the initial operation. Thrombosis of the mechanical valve occurred after the TVR. Treatment with urokinase for the thrombolytic therapy failed to improve the valve opening. Finally 12 years after the TVR, replacement of the mechanical valve with a phi 27 mm Carpentier-Edwards bovine pericardial valve was performed. Case 2: The patient, at 21 years old, received open-heart surgery to close an atrial septal defect. At 40 years of age, mitral and tricuspid valve replacements were performed because regurgitation developed in both valves. The mitral and tricuspid valves were replaced with phi 27 mm and 31 mm St. Jude Medical valves, respectively. Thrombosis of the mechanical valve used for the TVR occurred 2 months after the replacement. The mechanical valve was replaced with a phi 27 mm Carpentier-Edwards bovine pericardial valve. In both cases, subjective symptoms improved and prosthetic valve complications did not occur after re-replacement with the bovine pericardial valve. These cases suggested that for TVR a bovine pericardial valve of sufficient size would be better to select than a mechanical valve.

Adult↗
PubMed1990

Loss of the 3p25.3 band is critical in the manifestation of del(3p) syndrome: karyotype-phenotype correlation in cases with deficiency of the distal portion of the short arm of chromosome 3.

Two patients with monosomy for the distal portion of the short arm of chromosome 3 are described. Chromosome analysis on prometaphase cells demonstrated a karyotype of 46,XX,del(3) (p25.3) in one patient and 46,XX,r(3)(p26.1q29) in the other. The former patient showed characteristic clinical manifestations of the 3p- syndrome, including growth failure, mental retardation, microcephaly with a flat occiput, triangular face, synophrys, blepharoptosis, hypertelorism, broad and flat nose, long philtrum, down-turned mouth, micrognathia, apparently lowset and malformed ears, fingers abnormalities, and deafness. The latter patient had a nonspecific phenotype with mental retardation, growth failure and microcephaly. Karyotype-phenotype comparisons in the present cases and 16 previously reported cases with deficiency of the distal portion of 3p suggests that deficiency of the 3p25.3 band is critical to produce the main clinical manifestations of the del(3p) syndrome.

Chromosome Deletion↗
PubMed1990

Clonal composition of benign and malignant human thyroid tumors.

We determined clonality of thyroid tumors from female patients who had restriction fragment length polymorphisms (RFLP) in the X chromosome genes hypoxanthine phosphoribosyltransferase (HPRT) or phosphoglycerate kinase (PGK). We screened normal thyroid tissue from 59 female patients; of the informative cases 14 were heterozygous for a Bgl I site on PGK and 4 were heterozygous for a Bam HI site on HPRT. In monoclonal tumors, one of the polymorphic alleles was selectively digested after additional digestion with Hpa II, a methylation sensitive enzyme, whereas in polyclonal tissue both were decreased to a similar extent. Normal thyroid tissue from all patients showed a polyclonal pattern. Of the 18 tumors studied, 12 were solitary thyroid nodules, and 6 were obtained from multinodular goiters (MNG). The following were monoclonal: 6/6 follicular adenomas, 2/2 follicular carcinomas, and 1/1 anaplastic carcinoma. Two of the three papillary carcinomas showed intermediate patterns, possibly due to contaminating effects of stromal tissue present in most of these neoplasms. Of the six nodules from MNG, four were polyclonal. The two largest gave a distinct monoclonal pattern. Most solitary thyroid tumors are monoclonal, supporting a somatic cell mutation model of thyroid neoplasm formation. Nodules from MNG are largely hyperplastic, although monoclonal neoplasms do occasionally arise within these glands. The specific somatic mutations leading to clonal expansion and determination of tumor phenotype are presently unknown.

Adenoma↗
PubMed1990

H-ras protooncogene mutations in human thyroid neoplasms.

Structural alterations of protooncogene sequences may be involved in the pathogenesis of human neoplasms. We screened 54 thyroid tumors (36 benign and 18 malignant) for gene rearrangements of the protooncogenes c-myc, c-myb, c-fos, c-erb-B1, c-erb-B2, c-erb-A, N-ras, K-ras, and H-ras. Only mutations of H-ras were observed. None of the 15 colloid adenomas examined had detectable H-ras rearrangements. Of the remaining tumors, we observed mutations of H-ras in 4 benign and 4 malignant neoplasms. Gene amplification was found in 5 tumors. An aggressive recurrent papillary carcinoma had a marked amplification of one of the H-ras alleles. The amplified allele was truncated, in that the 3' variable tandem repeat was not a part of the amplification unit, and contained a codon 12 point mutation leading to a valine for glycine substitution. We also observed the association of low copy gene amplification with a codon 12 valine for glycine mutation in a follicular adenoma. Two tumors contained H-ras EcoRI polymorphisms not present in the DNA of normal thyroid from the same individuals, and one follicular carcinoma showed loss of an H-ras allele. Ras protooncogenes may become transforming by quantitative mutations, leading to increased expression, or qualitative mechanisms, through activating point mutations. Both of these appear to coexist in thyroid neoplasms, and it may be that a combination of both mechanisms is capable of inducing a more complete spectrum of neoplastic phenotypes.

Base Sequence↗
PubMed1990

Point mutations of ras oncogenes are an early event in thyroid tumorigenesis.

Identifying the nature of the genetic mutations in thyroid neoplasms and their prevalence in the various tumor phenotypes is critical to understanding their pathogenesis. Mutational activation of ras oncogenes in human tumors occurs predominantly through point mutations in two functional regions of the molecules, codons 12, 13 (GTP-binding domain) or codon 61 (GTPase domain). We examined the prevalence of point mutations in codons 12, 13, and 61 of the oncogenes K-ras, N-ras, and H-ras in benign and malignant human thyroid tumors by hybridization of PCR-amplified tumor DNA with synthetic oligodeoxynucleotide probes. None of the eight normal thyroid tissues harbored point mutations. Four of nineteen nodules from multinodular goiters (21%), 6/24 microfollicular adenomas (25%), 3/14 papillary carcinomas (21%), and 0/3 follicular carcinomas contained ras point mutations. The predominant mutation was a valine for glycine substitution in codon 12 of H-ras. None of the multinodular goiter tumors known to be polyclonal (and thus due to hyperplasia) had point mutations, whereas one of the two monoclonal adenomas arising in nodular glands contained in H-ras codon 12 valine substitution, which was confirmed by sequencing the tumor DNA. These data show that ras activation is about equally prevalent in benign and malignant thyroid neoplasms, and thus may be an early event in the tumorigenic process.

Adenocarcinoma↗
PubMed1990

[Dental treatment for children under general anesthesia].

A clinico-statistical survey was carried out on dental treatment for children under general anesthesia who visited the clinic of Pedodontic Department, Matsumoto Dental College Hospital during the period of 1986 to 1989. The number of cases subjected in this survey was 108 (57 boys 51 girls), aged from one year and 5 months to 8 years and 9 months. All of these patients were admitted to the hospital for 3 days and were treated under general anesthesia, using GOE in 107 cases (in 80 cases by nasal intubation, in 27 cases by oral intubation). One case was administrated by intravenous anesthesia with Ketamine. The results were as follows: 1. The patient ages of the patients ranged from one year 5 months to 8 years 9 months. 2. Thirteen percent of the patients were handicapped. Fifty three percent of the patients had to visit hospitals in remote areas. 3. The number of restored teeth per patient was 15 on the average. The teeth were treated with composite resin filling in 8.5 teeth, composite resin crown in 2.6 teeth, metal crown 3.6 teeth and other material in 0.8 (extraction). 4. Pulpal treatment was carried out on 42 percent of the subjected teeth. 5. The average anesthesia administration time was 3 hours and 28 minutes. No serious trouble was observed although minor complications were seen post-operatively such as high fever or vomiting in some cases.

Anesthesia, Dental↗
PubMed1990

[Frozen blood from one closely related donor reduced complications of blood transfusion without adverse effects in the open-heart surgery].

We used frozen blood from one closely related donor in 24 patients (group I) who underwent open heart surgery for congenital heart disease, in order to reduce of complications from a large quantity of blood transfusion. Blood of 600-2200 ml was collected from the single donor and was kept frozen until the operation. Two conditions of the patients were instituted, (1) body weight less than or equal to 40 kg (2) the single donor is father or mother or a close relative. The group of these patients was compared with patients using frozen autologous blood (group II) and patients using banked blood (group III). In group I patients two times of decline of red blood cell counts (RBC), hematocrit (Ht), hemoglobin (Hb) and total protein (TP) were noticed. The first was the period during the cardio-pulmonary bypass. The second was the time about one week after the transfusion of frozen red cells. But degree of the decline was uneventful clinically. The increment of complications induced from the use of frozen red cells was not noticed, and there was no case of serum hepatitis in group I patients. We concluded that the open-heart surgery using frozen blood cells (single donor), if the application was appropriate, could be undergone safely and would be effective on reducing infection and reaction induced from blood transfusion.

Adolescent↗
PubMed1990

[A case of modified Fontan operation for complete atrioventricular canal of right dominance with double-outlet right ventricle, common atrioventricular valve regurgitation].

A 6-year-old boy was diagnosed to have complete atrioventricular canal (CAVC) with double-outlet right ventricle (DORV), common atrium and common atrioventricular valve regurgitation. The atrioventricular junction predominantly connected to the right ventricle (right dominance) and the left ventricle was hypoplastic (LVEDV = 64% of normal). The combination of DORV with right dominant CAVC makes more difficult to make intra-ventricular rerouting. A modified Fontan procedure, atrial partition and DeVega's annuloplasty were successfully performed. It is concluded that Fontan procedure might be preferable rather than intra-ventricular rerouting in this case.

Child↗
PubMed1990

[Post-operative evaluation of a 17 mm diameter Björk-Shiley Monostrut prosthesis for aortic valve replacement--pressure gradient and effective valve area].

A 17 mm diameter Björk-Shiley Monostrut prosthesis was implanted in a 64-year-old female for aortic valve replacement in a semi-emergency. This valve was one of the smallest valves which were available in Japan. The patient was admitted because of severe hemolytic anemia and heart failure. Echocardiography showed regurgitation and calcification of Ionescu-Shiley tissue valve which was implanted 5 years ago. The patient's body surface area was 1.2 m2. Because of narrow aortic annulus, we could barely implant a 17 mm diameter Björk-Shiley Monostrut prosthesis. The valve function was examined by Brockenbrough method. During catheterization, the heart rate was 85 b/min and cardiac index was 3.00 l/min/m2. In these hemodynamic conditions, simultaneous measurements of aortic and left ventricular pressures revealed only 9 mmHg mean systolic pressure gradient. Similarly, 20 mmHg of pressure gradient across the implanted valve was obtained by Gorlin's formula. We could calculate that the effective orifice area of a 17 mm diameter Björk-Shiley Monostrut prosthesis was 1.0 cm2. Postoperative echocardiography demonstrated 42 mmHg systolic pressure gradient across this prosthesis by Doppler techniques, and left ventricular wall thickness was not decreased. To best our knowledges, this was the first case in which post-operative evaluation such a small prosthesis was measured.

Aortic Valve↗
PubMed1989

Local cerebral glucose utilization in the postictal phase of amygdaloid kindled rats.

Local cerebral glucose utilization was measured by means of the quantitative autoradiographic 2-[14C]deoxyglucose method during the postictal phase of various seizure stages of amygdaloid kindling in conscious rats. The partially kindled animals exhibited a partial seizure such as chewing and/or head nodding, and the fully kindled animals, a generalized tonic-clonic convulsion. The control animals were implanted with an electrode, but not electrically stimulated. Cerebral glucose utilization of the fully kindled animals was deeply depressed in the postictal phase as compared to the control, and that of the partially kindled animals was moderately decreased. The side-to-side differences of cerebral glucose utilization were observed only in the partially kindled group in which glucose utilization was more depressed on the side of stimulation. Among the structures with depressed glucose utilization, only one structure, the interpeduncular nucleus, showed a relative increase in glucose utilization during the postictal phase of the kindled groups. As the postictal phase has been considered as a period of inhibition, these results may indicate that the neural networks linking the interpeduncular nucleus play an active role in the mechanisms of termination of a seizure and postictal refractoriness.

Amygdala↗