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Biomedical subjects

K Kamiya

Publications and source records attributed to K Kamiya.

At least 19 recordsLinked to original sources
PubMed1995

Association of minisatellite instability with c-myc amplification and K-ras mutation in methylcholanthrene-induced mouse sarcomas.

Instability of microsatellite sequences are frequently found in human tumors. In addition, minisatellite sequences, another group of highly unstable sequences, serve as sensitive markers of genetic instability. We have studied minisatellite instability in methylcholanthrene-induced mouse sarcomas. These sarcomas frequently carry the amplified c-myc gene. Seven sarcomas without the amplification and seven others with the amplification were selected randomly. Regardless of the state of the c-myc gene amplification, these sarcomas exhibited a varying degree of transplantability in syngeneic mice. The hypervariable mouse minisatellite locus Ms6hm was found to be highly unstable, specifically among sarcomas with the amplified c-myc gene. However, chromosome instability, as analyzed by micronucleus assay, was observed similarly for two groups of sarcomas. In addition, transversion of G to C and A to T was detected at the K-ras gene in four of the seven sarcomas with the amplified c-myc gene, and these mutations are thought to be induced directly by methylcholanthrene. Thus, concomitant occurrence was observed for three seemingly unrelated mutations, amplification of the c-myc locus, point mutation of the K-ras gene, and instability at the hypervariable mouse minisatellite locus. The present study indicates a possible involvement of K-ras mutation and c-myc amplification in induction of genetic instability in methylcholanthrene-induced mouse sarcomas.

Animals↗
PubMed1995

Evidence that carcinogenesis involves an imbalance between epigenetic high-frequency initiation and suppression of promotion.

Evidence is presented in support of the hypothesis that cancer development depends on an imbalance between highly frequent epigenetic initiation and suppression of promotion of the initiated cells. When irradiated clonogenic mammary epithelial cells are transplanted and hormonally stimulated, they give rise to clonal glandular structures within which carcinomas may arise. In the current study, the cancer incidence in grafts of approximately 13 7-Gy-irradiated clonogens per site indicated that at least 1 of approximately 95 clonogens was radiogenically initiated. A similar initiation frequency had been seen in grafts of approximately 5 methylnitrosourea (MNU)-treated clonogens. Such initiation is thus far more frequent than specific locus mutations. In sites grafted with larger cell inocula, cancer incidences per clonogen were suppressed inversely as the numbers of irradiated or MNU-treated clonogens per graft increased. Addition of unirradiated cells to small irradiated graft inocula also suppressed progression. Radiation and MNU thus produce quantitatively, and perhaps qualitatively, similar carcinogenesis-related sequelae in mammary clonogens.

Adenocarcinoma↗
PubMed1995

Collateral artery bypass in Buerger's disease: report of a novel procedure.

A 25-year-old man was admitted to our hospital for treatment of a painful ulcer on his left fourth toe, 9 years after undergoing lumbar sympathectomy and 4 years after undergoing bypass, both of which had been unsuccessful. Angiography demonstrated diffuse arterial occlusion in the lower extremities except for a persistent sciatic artery and a sural artery, which was the main collateral. Thus, reversed bifurcated saphenous vein bypass from the sciatic artery to the sural artery and the posterior tibial artery was performed utilizing Esmarch's rubber bandage as a substitute for a vascular clamp to control bleeding intraoperatively. The ulcer healed promptly and the patient was discharged symptom-free 1 month postoperatively. This case report demonstrates the advantage of performing collateral arterial bypass and illustrates some of the technical challenges associated with this procedure.

Adult↗
PubMed1995

Rupture of an isolated internal iliac artery aneurysm into the rectum: report of a case.

Aneurysmal rupture into the intestinal tract is a rare but disastrous complication of an internal iliac artery aneurysm. We report herein the successful surgical repair of a fistula between a huge aneurysm of the right internal iliac artery and the rectum in an 81-year-old man. After a femoro-femoral cross-over bypass had been performed, the aneurysm was opened and its patent arterial branches were ligated with sutures. The fistula was then intra-aneurysmally sutured and covered with an omental flap. The diagnostic and therapeutic approaches to this severe complication are discussed with a review of the literature following the presentation of this case.

Aged↗
PubMed1995

A case of spinal low-grade astrocytoma with exophytic and intracranial extension.

BACKGROUND: Ventral exophytic growth of a spinal intramedullary glioma into the cranial cavity is an unusual condition. CASE DESCRIPTION: A 16-year-old boy was admitted because of lower cranial nerve dysfunction and acute hydrocephalus. Magnetic resonance images showed an intramedullary mass lesion in the upper cervical spinal cord with exophytic extension into the medullary and prepontine cisterns. The patient underwent suboccipital craniectomy and C1-2 laminectomy for decompression and histologic evaluation. The histopathologic findings were characteristic of astrocytoma grade II. Although radiotherapy was performed, the patient died 7 months later. CONCLUSIONS: This is considered to be a rare case of spinal low-grade astrocytoma with ventral exophytic intracranial extension.

Adolescent↗
PubMed1995

Radiation-induced apoptotic cell death in human gastric epithelial tumour cells; correlation between mitotic death and apoptosis.

The mode of cell death in cells undergoing mitotic death after gamma-irradiation was studied in seven human gastric epithelial tumour cell lines and two strains of normal gastric fibroblasts. Apoptotic cells were frequently observed in all tumour lines after irradiation, whereas the two fibroblast strains were quite low in apoptosis frequency. The advent of apoptosis depended on the radiation doses and incubation time. Detailed analysis of one of the carcinoma lines, SH101-P4, revealed that G2-phase arrest was maximum at 12 h postirradiation. The cells began to escape G2 arrest by 24 h. Apoptotic cells began to increase at 12 h postirradiation and became maximal from 72 to 96 h. Apoptosis developed in the G1 phase of the cell cycle subsequent to the irradiation. These results suggest that apoptosis is one of the modes of mitotic death after irradiation.

Adenocarcinoma↗
PubMed1995

Dose-response of a radiation induction of a germline mutation at a hypervariable mouse minisatellite locus.

Dose-response of an induction of a germline mutation was studied at a hypervariable mouse minisatellite locus, Ms6hm, which consists of tandem repeats of a sequence motif GGGCA. Male C3H/HeN mice were exposed to various doses of 60Co gamma-ray and mated with unirradiated C57BL/6N female mice. Matings were done at various time after irradiation to assess the effects of radiation on spermatozoa, spermatids and spermatogonia. DNA samples of F1 offsprings were analysed by Southern blotting for the repeat length mutation at the Ms6hm locus. The mutation frequency per gamete of the paternal allele was 9.1% for the unirradiated control group. The spermatids stage was most sensitive to radiation and a statistically significant dose-response was observed. The mutation frequency of the paternal allele in F1 mice increased to 22% for 1 Gy, 28% for 2 Gy, and 28% for 3 Gy. The spermatogonia stage was less sensitive to radiation, and the mutation frequencies of the paternal allele were 14% for 2 Gy, and 16% for 3 Gy. The spermatozoa stage germ cells were also less sensitive and the frequency of mutation of the paternal allele increased to 14% for 3 Gy. However, these increases were statistically not significant. Possible mechanisms of radiation induction of germline mutation at the hypervariable minisatellite locus will be discussed.

Alleles↗
PubMed1995

Over-expressed ZF5 gene product, a c-myc-binding protein related to GL1-Kruppel protein, has a growth-suppressive activity in mouse cell lines.

ZF5 encodes a zinc finger protein, which contains five C2H2-type zinc fingers showing homology with the zinc finger of the Kruppel family, and binds to two sites in the mouse c-myc promoter. We report the effect of over-expression of ZF5 on cell growth. ZnCl2 treatment suppressed the growth of a mouse fibroblast cell line (L cells) transfected with the wild-type ZF5 gene driven by the metallothionein promoter. Cells transfected with the wild-type ZF5 gene formed colonies two- to fivefold less efficiently than those transfected with the mutant ZF5 gene in P19, NIH3T3, 3T3-L1 and L cells. Over-expression of ZF5 did not cause c-myc down-regulation or arrest of the cell cycle, but increased the DNA content.

3T3 Cells↗
PubMed1995

[Exposure to blood during midwifery procedures--blood contact events to midwives occurred in a delivery room].

Midwives are often exposed to blood during delivery procedures. A study aimed at clarifying actual status of blood contact during midwifery procedures was performed. Observations in a delivery room were conducted to record blood contact events experienced by midwives from the time of episiotomy until 2 hour after expulsion of the placenta. All gloves used by midwives were collected and tested for holes. Blood contact was defined as any contact with blood of a parturition woman as recognized visually by an observer. During a one-month study period data was obtained from a total of 19 midwives (12 midwives and 7 student midwives) who assisted in 8 deliveries. All of the midwives wore gowns with long sleeves, gloves and caps but did not use eye protection or masks. None of the parturient women had Hepatitis B, Hepatitis C or acquired immunodeficiency syndrome. Deliveries caused widespread blood exposure to the midwives throughout the complete course. Protection from most of this exposure was provided by the gowns and gloves. However, direct blood contacts occurred to the fingers, hands or forearms in several midwives. These events were caused by partly because the midwives unintentionally performed procedures without gloves and partly because blood penetrated the gown and soaked to the skin. Direct blood contacts to the foot in two midwives and to the mouth in one also occurred. The overall perforation rate for gloves examined was 4 out of 154 (2.6%). Two gloves were broken during washing sharp instruments contaminated with blood, one was torn when wearing, and the remaining one appeared to have had a hole prior to use.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

A simple luminescence method for detecting lipid peroxidation and antioxidant activity in vitro.

The excited carbonyl species formed during lipid peroxidation may transfer their energy to dye molecules containing heavy atoms such as rose bengal to produce excited singlet state dye molecules. The excited dye then emits photons to return to its ground state. The aim of the present study was to investigate the relationship between methemoglobin (metHb)-induced lipid peroxidation, rose bengal luminescence, and O2 consumption in a system containing 0-850 mu M phospholipid and 1 mu M metHb and 1 mu M rose bengal in Tris-HCl buffer, pH 7.4. The rapid rise in rose bengal luminescence was accompanied by a rapid rise in O2 consumption. Further, the luminescence of rose bengal could be quenched by alpha -tocopherol or probucol present in the phospholipid liposomes, with the latter being strikingly more effective than the former. This simple luminescence method is a useful practical approach to detect lipid peroxidation and determined antioxidant effects of water insoluble compounds in vitro.

Antioxidants↗
PubMed1994

Ca(2+)-calmodulin mediated modulation of the electrical coupling of ventricular myocytes isolated from guinea pig heart.

The mechanism for the regulation of junctional conductance (gj) by Ca2+ was examined in paired ventricular myocytes isolated from guinea pig heart. One cell of the pair was voltage-clamped by a single-patch pipette, and gj was measured after perforation of the non-junctional membrane of the partner cell. The average value of gj under control condition at pCa 9.0 was 181 +/- 13 nS (n = 30). An elevation of calcium concentration ([Ca2+]i) in the intracellular perfusate from pCa 9.0 to pCa 5.7 resulted in a decrease of 32 +/- 5% in gj (n = 18). In myocytes pretreated with W7 (10(-4) M), a similar elevation of [Ca2+]i caused a decrease of only 10 +/- 3% in gj (n = 6), indicating a protective action of W7 against Ca(2+)-mediated electrical uncoupling. W5 (10(-4) M), a non-chlorinated derivative of W7, did not show such a protective action. Calmodulin (10(-5) M) had no effects on gj at pCa 9.0. However, at moderately elevated [Ca2+]i condition at pCa 7.0, calmodulin (10(-5) M) decreased gj by 29 +/- 6% (n = 4). These results suggest that calmodulin may play an important role in the Ca(2+)-mediated regulation of gap junctional channel function in the cardiac ventricular cells.

Action Potentials↗
PubMed1994

Distal arterial reconstruction using Esmarch's bandage technique to salvage upper extremity function in thoracic outlet syndrome caused by cervical ribs: a report of two cases.

We present herein the cases of two patients with thoracic outlet syndrome (TOS) who required arterial reconstruction due to gangrene of the fingers and/or hand. In both patients, the cervical ribs had produced intimal injury of the subclavian arteries, and the successive distal arterial embolism brought about severe ischemia of the affected upper extremity. To treat the TOS, the cervical ribs were resected through a supraclavicular incision. In the first patient, arterial reconstruction was performed from the subclavian artery to the radial collateral artery, a branch of the deep brachial artery, which resulted in minimizing amputation of the gangrenous hand. In the second patient, resection and direct anastomosis of the injured subclavian artery were performed, and bypass surgery from a brachial artery to an interosseous artery was carried out, preserving finger function. Reversed saphenous vein grafts were utilized and Esmarch's bandage technique was applied as a substitute for a vascular clamp in both patients. Following these case reports, we discuss the technique of performing distal bypass in the upper extremities and comment on the usefulness of Esmarch's bandage technique for preserving upper extremity function.

Adult↗
PubMed1994

Peripheral anterior inferior cerebellar artery aneurysms.

Two cases of peripheral anterior inferior cerebellar artery (AICA) aneurysms are reported. The first case was a 60-year-old man who showed frequent attacks of subarachnoid hemorrhage (SAH) and hearing disturbance. His aneurysm was obliterated by trapping the AICA and his neurologic status was unchanged compared with preoperatively. The second case had SAH without cranial nerve involvement; this aneurysm was obliterated by neck clipping. He was discharged without neurologic deficit. Peripheral AICA aneurysm has already been reported in 48 cases including arteriovenous malformation-associated cases. This aneurysm may show cranial nerve involvement (seventh and eighth) without SAH as in the case of internal carotid-posterior communicating artery aneurysms. We review the clinical signs of these cases and discuss them from the point of view of anatomic variations of the AICA and internal auditory artery.

Aged↗
PubMed1994

Radiation induction of germline mutation at a hypervariable mouse minisatellite locus.

Paternal 60Co gamma-irradiation was tested for the induction of germline mutation at the mouse hypervariable minisatellite locus, Ms6hm. Male C3H/HeN mice were exposed to 3 Gy 60Co gamma-ray and mated with C57BL/6N females. Matings were made at 1-7, 15-21 and 71-77 days post-treatment to test spermatozoa, spermatids and spermatogonia stages. Reciprocal crosses were also made with irradiated C57BL/6N males. Southern analysis was carried out on DNA from parents and F1 mice. The paternal mutation frequencies per gamete of the Ms6hm locus were 8.3, 13, 28 and 15% for the C3H/HeN control, exposed spermatozoa, spermatids and spermatogonia stages, respectively. The paternal mutation frequencies per gamete were 7.7% for the C57BL/6N control and 13% for the C57BL/6N exposed spermatozoa stage. The increase in the paternal germline mutation frequency was statistically significant for C3H/HeN spermatids irradiation (p < 0.005). The induced mutation frequencies were of the order of 10(-1), and was too high to be accounted for by the direct action of radiation on the locus. These results suggest the presence of a previously unexpected mechanism of radiation induction of germline mutation. In addition, we demonstrate that the hypervariable minisatellite locus can serve as a sensitive monitor for genetic damages to germline cells.

Animals↗
PubMed1994

Factor IX Bm Kiryu: a Val-313-to-Asp substitution in the catalytic domain results in loss of function due to a conformational change of the surface loop: evidence obtained by chimaeric modelling.

Factor IX Kiryu is a naturally occurring mutant of factor IX that has 2.5% coagulant activity, even though normal plasma levels of factor IX antigen are detected. Factor IX Kiryu was purified from a patient's plasma by immunoaffinity chromatography with a calcium-dependent anti-factor IX monoclonal antibody column. It was cleaved normally by factor XIa in the presence of Ca2+, yielding a two-chain factor IXa. However, the resulting factor IXa showed only 1.5% of the normal factor IXa in terms of factor X activation in the presence of factor VIII, phospholipids, and Ca2+, and had 20% of the normal esterase activity for Z-Arg-p-nitrobenzyl ester. Therefore factor IXa Kiryu showed the defect of the catalytic triad or primary substrate binding site as well as defective interaction with factors VIII/X. Single-strand conformational polymorphism analysis and DNA sequencing of the amplified DNA revealed a missense point mutation, a T-to-A substitution at nucleotide number 31,059 of the factor IX Kiryu gene. This mutation resulted in the amino acid substitution of Val-313 by Asp in the catalytic domain. Restriction enzyme analysis of the amplified DNA showed that the mutation was inherited from the patient's mother. The chimaeric method was employed to construct a model of the serine protease domain of factor IXa, and the resultant model suggested that the Val-313 to Asp substitution altered the conformation of the substrate-binding site. These data combined with our previous findings on a Gly-311-to-Glu mutant of factor IX suggest that the loop conformation from Gly-311 to ARg-318 is important for the expression of coagulant activity.

Amino Acid Sequence↗
PubMed1994

West syndrome associated with porencephaly.

A 3-year-old boy with West syndrome who was shown to have a cystic lesion on magnetic resonance imagings underwent surgical treatment. He had been initially managed with several antiepileptic drugs, but abnormalities on electroencephalography (EEG) persisted. Histological examination of the cystic wall obtained during surgery suggested porencephaly. Two years and 2 months later the child remained seizure-free and his EEG remarkably improved.

Adrenocorticotropic Hormone↗
PubMed1994

Nature of protein adsorption in artificial tear solution on plasma-irradiated polymethylmethacrylate surface.

To evaluate the effect of plasma treatment on protein adsorption onto a polymer surface, we carried out Ar plasma irradiation on polymethylmethacrylate (PMMA) plate and examined the adsorption behavior of protein after immersion of plasma treated PMMA plate in the artificial tear solution containing lysozyme, albumin and gamma-globulin. It was found that the total adsorption of protein in the artificial tear solution to PMMA is suppressed by the Ar plasma treatment. But the adsorption of each component protein differs according to the surface condition of polymers and obviously corresponds to the change with time in the surface wettability. It is concluded that introduction of a hydrophilic group into the PMMA surface by plasma treatment and coming off of it are associated with the adsorption behavior of proteins. Since the adsorption of protein to the plasma-treated PMMA surface changes over time, care should be exercised in determining it, when an attempt is made to clarify the effect of plasma irradiation on the adsorption to the plasma-irradiated polymer surface.

Adsorption↗