Biomedical subjects

Y Katoh

Publications and source records attributed to Y Katoh.

At least 73 records · Page 4Linked to original sources

PubMed1998

[A case of renal cell carcinoma in a nonfunctioning kidney caused by staghorn calculus].

A 62-year-old man was referred to our clinic with a chief complaint of gross hematuria. He had bilateral renal staghorn calculi at the age of 50 years and had undergone left nephrolithotomy. However, no treatment had been given to the right staghorn calculi associated with nonfunctioning kidney. Imaging diagnosis demonstrated no mass lesions in the bilateral kidneys. Right nephrectomy revealed renal cell carcinoma, tubular type, mixed subtype, G2, INF-beta with lymph node metastasis to the renal hilum. Cancer cells infiltrated diffusely throughout the entire renal parenchyma. He died of progressive metastases 15 months postoperatively.

Carcinoma, Renal Cell↗

PubMed1997

Characterization of the pUC19-lacZC141 reversion system for assaying chemical mutagenesis.

pUC19-lacZC141 DNA contains a proline codon at positions 141 to 143, where an alanine codon normally appears in the original lacZ gene. pUC19-lacZC141 DNA was produced using site-directed mutagenesis. After transfection of pUC19-lacZC141 DNA into lacZ hosts, the transformants produce white colonies on an agar plate containing X-gal and IPTG. lacZ+ revertants can be identified by their dark- and light-blue colony color against a background of non-mutant white colonies, indicating restoration of beta-galactosidase activity. N-Methyl-N'-nitro-N-nitrosoguanidine (MNNG) and methylmethanesulfonate (MMS) were used to characterize the pUC19-lacZC141 DNA reversion assay. Mutagenesis resulting from methylated DNA was examined in Escherichia coli strains JM109, BMH71-18mutS, and SURE, which differ in their repair systems for DNA damage. In JM109 and BMH71-18mutS, mostly G:C-->A:T transitions and some G:C-->C:G or G:C-->T:A transversions were observed. E. coli SURE produced, in addition, frameshift mutations (approximately 10%). The DNA sequence analysis of 174 induced mutants indicated that the major effect of methylation is on single base-pair substitutions with a slight effect on deletion frameshifts. All mutations are consistent with miscoding of guanine or cytosine adducts or lesions. Transitions account for 158 of 165 (96%) induced base substitutions. Approximately 93% of the base-substitution mutations occurred at the expected positions 141 to 143 in the lacZ gene. The pUC19-lacZC141 assay was sufficiently sensitive to allow the detection of mutations in lacZ- hosts with different repair mechanisms. The pUC19-lacZC141 DNA reversion system will permit the assaying of other chemicals not otherwise amenable to mutagenesis studies.

DNA Methylation↗

PubMed1997

An Nrf2/small Maf heterodimer mediates the induction of phase II detoxifying enzyme genes through antioxidant response elements.

The induction of phase II detoxifying enzymes is an important defense mechanism against intake of xenobiotics. While this group of enzymes is believed to be under the transcriptional control of antioxidant response elements (AREs), this contention is experimentally unconfirmed. Since the ARE resembles the binding sequence of erythroid transcription factor NF-E2, we investigated the possibility that the phase II enzyme genes might be regulated by transcription factors that also bind to the NF-E2 sequence. The expression profiles of a number of transcription factors suggest that an Nrf2/small Maf heterodimer is the most likely candidate to fulfill this role in vivo. To directly test these questions, we disrupted the murine nrf2 gene in vivo. While the expression of phase II enzymes (e.g., glutathione S-transferase and NAD(P)H: quinone oxidoreductase) was markedly induced by a phenolic antioxidant in vivo in both wild type and heterozygous mutant mice, the induction was largely eliminated in the liver and intestine of homozygous nrf2-mutant mice. Nrf2 was found to bind to the ARE with high affinity only as a heterodimer with a small Maf protein, suggesting that Nrf2/small Maf activates gene expression directly through the ARE. These results demonstrate that Nrf2 is essential for the transcriptional induction of phase II enzymes and the presence of a coordinate transcriptional regulatory mechanism for phase II enzyme genes. The nrf2-deficient mice may prove to be a very useful model for the in vivo analysis of chemical carcinogenesis and resistance to anti-cancer drugs.

Animals↗

PubMed1997

A simple quantitative measurement of mRNA of human beta-actin by reverse transcription competitive PCR with a compact digital camera.

Reverse transcription (RT) competitive polymerase chain reaction (PCR) is a sensitive and useful technique for the absolute quantitation of mRNA level. We developed a competitive PCR method with a compact digital camera DC 40 (Eastman Kodak Company, NY, U.S.A.) for the measurement of human beta-actin cDNA (mRNA), a reference gene in an analysis for target gene expression. The devised method, compared with currently used methods, was easy, safe, sensitive, and highly reproducible to assay an infinitesimal level of cDNA (mRNA).

Actins↗

PubMed1997

[A new model of delayed healing of acetic acid ulcers in rats by indomethacin via osmotic pump].

Gastric ulcers were produced in male Donryu rats (8-weeks-old) by subserosal injection of 20 microliters of 20% acetic acid. Five days later, an indomethacin (IND)-filled osmotic pump (OP) was implanted into the dorsal subcutaneous space in the rats and maintained for 2, 3 or 4 weeks. The natural healing of the acetic acid-induced ulcers was significantly (P < 0.05) delayed by administration of IND via OP implanted for 4 weeks. Two, 3 and 4 weeks after OP implantation, the plasma IND levels was 1.87 +/- 0.13, 2.43 +/- 0.16 and 0.74 +/- 0.26 (micrograms/ml), respectively, showing that a steady state IND plasma level was maintained for 3 weeks. The gastric mucosal PGE2 levels in rats with ulcers for 3 weeks after implantation of OP were significantly (P < 0.05) reduced by IND (IND(-):576.6 +/- 83.9 pg/mg, IND(+):355.6 +/- 34.7 pg/mg). Repeated administration of enprostil, famotidine and rabeprazole at 25 micrograms/kg, 100 mg/kg and 10 mg/kg (p.o., b.i.d.), respectively, showed anti-ulcer activity. Teprenone and rebamipide had only slight anti-ulcer activity. These findings indicated that this model of delayed healing of acetic acid ulcers by IND using OP is useful for investigating the anti-ulcer activity of drugs.

Acetates↗

PubMed1997

Effect of an adhesive bonding system on wear resistance of resin composite restorations.

The effect of an adhesive bonding system on wear of posterior resin composite restorations was investigated using an in vitro three-body wear test. Resin composite restorations were placed with an adhesive system (Syntac) in Class I cavities on occlusally flattened extracted molars. Control restorations were prepared with the same resin composites but without etching or bonding. The surface of each restoration was replicated with poly(vinyl siloxane) for epoxy dies at baseline and after every 100,000 cycles until the completion of 400,000 wear cycles. The generalized wear (contact-free wear) of the composite restorations was scanned and traced at the same stage of replication with a profilometer. The use of an adhesive system significantly reduced the wear rate of the resin composites used in this study.

Composite Resins↗

PubMed1996

Cloning and sequencing of novel genes from Vibrio alginolyticus that support the growth of K+ uptake-deficient mutant of Escherichia coli.

Novel genes that functionally complement the growth of K+ uptake-deficient mutant strain of Escherichia coli TK420 have been cloned from the marine bacterium Vibrio alginolyticus. The nucleotide sequence revealed three open reading frames. The second gene was homologous to proC gene and allowed the growth of proC-defective mutant strain of E. coli chi 342 in the absence of proline. The first and third genes, but not proC, were required for the growth of TK420 in a synthetic medium containing 10 mM K+ and 100 mM Na+. Since K+ uptake activity of TK420 was restored by the introduction of these genes, these two genes were considered to be directly related to K+ transport. Homologous genes were found in E. coli, but their functions have not been reported.

Amino Acid Sequence↗

PubMed1996

Tumor angiogenesis and expression of thymidine phosphorylase/platelet derived endothelial cell growth factor in human gastric carcinoma.

To investigate the relationship between tumor angiogenesis and the expression of platelet-derived endothelial cell growth factor/thymidine phosphorylase (PD-ECGF/dThdPase) and between patients' survival and the expression of PD-ECGF/ dThdPase in human gastric carcinoma tissues, we performed immunohistochemical studies with anti-PD-ECGF/dThdPase and anti-CD34 monoclonal antibodies. Out of 154 gastric carcinoma tissue samples, 61 (40%) were evaluated as PD-ECGF/ dThdPase-positive. The expression of PD-ECGF/dThdPase was significantly associated with the intratumoral microvessel counts (P < 0.0001) and the incidence of hematogenous metastasis (P < 0.05). Intratumoral vessel counts were significantly correlated with overall survival of 154 patients (P < 0.000001). Cox proportional hazards model showed that tumor vasculature was an independent and strong prognostic variable. However, the prevalence of the expression of PD-ECGF did not associate the overall survival. We suggest that expression of PD-ECGF/dThdPase plays a role in the promotion of angiogenesis in human gastric carcinomas, without any definite influence on patient's survival.

Adenocarcinoma↗

PubMed1996

The limit of low speed peripheral nerve elongation; neurological and circulatory aspects.

We studied peripheral nerve elongation of rabbit sciatic nerves. External fixators developed in our department were applied to 32 rabbit femurs in vivo. The rabbits underwent osteotomy of the femur and were divided into two groups subjected to different sciatic nerve elongation speeds: group I (0.45 mm/day) and group II (1.35 mm/day). The sciatic nerves were elongated 1.5, 3.0, 4.5, 6.0 and 7.0 cm by the external fixators, and the corresponding actual percentage of elongation of the nerves were 8, 16, 24, 30 and 40%. After elongation, nerve electrophysiology, nerve blood flow and pathology were studied. Forty percent elongation decreased nerve blood flow to 69 +/- 5.1% of contralateral controls in group I and to 20 +/- 4.8% in group II. Although no decrease in motor conduction velocity (MCV) was observed at any elongation distance, compound muscle action potential (CMAP) amplitude gradually decreased with increasing elongation. In group I, after 40% elongation, specimens showed the following pathologic changes: thinning of myelin sheath, atrophy and detachment of the axon from the myelin sheath. Furthermore, in group II, 40% elongation induced disorganization of the myelin sheath and Wallerian degeneration. Consequently 40% elongation was regarded as critical at speeds of both 0.45 and 1.35 mm/day.

Action Potentials↗

PubMed1996

Prevalence of urolithiasis in Kaizuka City, Japan--an epidemiologic study of urinary stones.

BACKGROUND: According to the results of nationwide surveys, the prevalence of urolithiasis has been steadily increasing in Japan. However, these surveys relied on hospital statistics, and there has been no survey of the prevalence of urolithiasis in Japan utilizing postal questionnaires. We surveyed the prevalence of urolithiasis among the inhabitants of Kaizuka City. METHODS: A total of 3,000 inhabitants ranging from 20 to 59 years old were randomly selected from the census register in numbers consistent with the population distribution of each district and sex by municipal computerized system. RESULTS: A total of 1,975 postal questionnaires were returned, and 1,972 (65.7%) were considered valid. Of the respondents, 137 (6.95%) had a history of stones (men; 9.64%, women; 4.51%). The annual incidence of urolithiasis for Kaizuka citizens aged from 20 to 59 years old in 1991 was 0.97%, and the lifetime prevalence of urolithiasis increased linearly with age, and it was 10.3% for respondents in their 50s. In the total survey population of 7,568, which included the respondents and their family members, 342 (4.52%) had a history of stones. Male administrative workers had a significantly higher prevalence than any other occupational group. The monthly expenditure on food by the families of stone formers was significantly greater than that by the families of non-stone formers. CONCLUSION: Extrapolation of the findings suggests that > 10% of the general population (> 13% of men and > 7% of women) can be expected to suffer from urolithiasis at least once in their lifetime.

Adult↗

PubMed1996

[Indications of parathyroidectomy for bone disease associated with secondary hyperparathyroidism].

BACKGROUND: The indications and suitable operative time of parathyroidectomy for secondary hyperparathyroidism were discussed. METHODS: From October 1978 to September 1994 parathyroidectomy was performed for 71 patients who had bone and/or joint pain due to secondary hyperparathyroidism. There were 37 men and 34 women (mean age 48.4 years). The duration of dialysis treatment before parathyroidectomy was 0.8 to 19 years, with a mean of 10.9 years. RESULTS: Postoperative subjective improvement was noted in 69% of the patients. No significant difference was observed between the improved and non-improved groups regarding age and the duration of dialysis treatment. But the improvement rate in female patients was significantly lower than that in male patients. CONCLUSION: Patients with high carboxyl-terminal PTH level and generalized fibrous osteitis were good suitable objects for parathyroidectomy. But, those with high serum aluminum level were unsuitable objects for it. Furthermore, 99mTc-Pyrophosphate bone scintigraphy and bone mineral determination using dual photon absorptiometry (DPA) or dual energy X-ray absorptiometry (DEXA) were proved to be valuable for patient selection for parathyroidectomy.

Adult↗

PubMed1996

[A case of genitourinary double cancers detected by health screening].

A 58-year-old male with left renal cell carcinoma and prostatic carcinoma occurring synchronously, is reported. He visited our hospital, because of the high level of serum prostate-specific antigen (PSA) pointed out in a health screening by his company. Prostatic cancer was detected in both lobes of the prostate by needle biopsy specimens and histopathology represented moderately > poorly differentiated adenocarcinoma. Magnetic resonance imaging (MRI) and computed tomography (CT) revealed no cancer invasion beyond the prostate and no lymph node metastasis. Bone scintigram showed no abnormal RI accumulation to bone. Therefore, his prostatic cancer was considered to be at stage B2. Abdominal ultrasound echogram showed the mass lesion in the left kidney. CT and angiogram also demonstrated a left renal tumor. Left radical nephrectomy was performed and histopathology showed a mixed subtype of renal cell carcinoma (stage: pT2b, pN0, pM0). Although 94 cases of double cancers associated with genitourinary organs have been reported in the Japanese literature, only 4 cases of double cancers of renal cell carcinoma and prostatic cancer have been reported.

Adenocarcinoma↗

PubMed1996

[Primary transitional cell carcinoma of the prostatic urethra: a case report].

A case of primary transitional cell carcinoma of the prostatic urethra is reported. A 60 year-old male, with a chief complaint of difficult urination consulted our clinic on March, 1994. Urethrography and endoscopic examination revealed the solitary tumor of the prostatic urethra and transurethral resection was performed. Histologically, the tumor was Grade 2 transitional cell carcinoma without submucosal invasion. The post-operative course was uneventful and no recurrence has been seen. To our knowledge, including our case, 10 cases of primary transitional cell carcinoma of the prostatic urethra have been reported in the Japanese literature.

Carcinoma, Transitional Cell↗

PubMed1996

[Polyorchidism: a case report and review of the literature].

An 11-year-old boy visited our department complaining of left scrotal painless mass from 6 months ago. The small mass was palpable beside the left testis. Ultrasonography shows isoechoic round shaped mass 5 mm in diameter. At surgery, the mass was connected with the left testis and epididymal head and sharply excised from them. Histological examination showed normal testicular architecture, but spermatogenesis was not found. We report the 18th case of polyorchidism in Japan and made some discussion about polyorchidism.

Child↗

PubMed1996

[A case of renal cell carcinoma presenting as spontaneous renal rupture].

A case of renal carcinoma presenting as spontaneous renal rupture is reported. A 50-year-old man was admitted to our hospital with the chief complaint of left lumbal pain. There was no evidence of recent trauma. Intravenous pyelography showed extravasation of perirenal area and space-occupying lesion at the left upper pole of the kidney. Left perirenal hemorrhage was found on computed tomography (CT scan). Suspecting extracapsular hemorrhage caused by rupture of the renal tumor, we performed nephrectomy. Histological diagnosis was renal cell carcinoma, alveolar type, clear cell subtype, grade 2, INF alpha, pT2. The patient has been well without local recurrence or distant metastasis for 9 months after the operation. To our knowledge, this is the 16th case or renal cell carcinoma with spontaneous rupture, reported in the Japanese literature, and the 7th case of extracapsular renal rupture.

Antineoplastic Agents↗

PubMed1995

Intracerebral hematoma in patients with ruptured cerebral aneurysms.

BACKGROUND: Intracerebral hematoma from ruptured aneurysms is one of the unfavorable factors for outcome in patients with subarachnoid hemorrhage. In this study, the clinical characteristics of intracerebral hematoma in patients with ruptured aneurysms were examined. METHODS: The subjects were 512 patients who had been admitted by day 3 after aneurysmal rupture without episodes of rebleeding before the initial computed tomography (CT) scan. They were divided into two groups according to the findings of initial CT; groups 1 and 2 comprised patients with and without intracerebral hematoma, respectively. RESULTS: Of the 512 patients, intracerebral hematoma was observed in 98 (19%). The incidence of intracerebral hematoma was higher in patients with distal anterior cerebral and middle cerebral artery aneurysms, compared with those at other sites (both, p < 0.01). Interhemispheric, callosal, and temporal lobe/sylvian hematomas were observed more frequently in patients with anterior communicating, distal anterior cerebral, and middle cerebral artery aneurysms, respectively, than in those with aneurysms at other sites. The incidence of rebleeding was 22% in group 1 and 14% in group 2 (p < 0.05). Clinical grades on admission were higher and outcome at 6 months after onset was less favorable in group 1 than in group 2 (both, p < 0.01). The larger the intracerebral hematoma, the higher was the clinical grade and the less favorable the outcome. However, when comparing management and surgical outcome under the same clinical grades, there was no significant difference between the two groups. CONCLUSIONS: There was a close correlation between the site of hematoma and that of the ruptured aneurysm. Poor outcome in patients with intracerebral hematoma seems to be related to severity of clinical grade on admission.

Adult↗

PubMed1995

Mutagenicity of O-diazoacetyl-L-serine (azaserine) and 6-diazo-5-oxo-L- norleucine (DON) in a soybean test system.

The mutagenicity of O-diazoacetyl-L-serine (azaserine) and 6-diazo-5-oxo-L-norleucine (DON), glutamine analogues, were assayed in heterozygous soybean plants (Y11y11), according to the appearance of mutational spots (yellow, dark green and twin) on the leaves. The mutagenicity of azaserine was detected at 0.1 mg/ml, and that of DON, at 0.05 mg/ml. DON was strongly cytotoxic at doses exceeding 0.1 mg/ml. After azaserine and DON treatment, large spots which occupied more than half the leaflet were found in the first and second compound leaves. The glutamine analogues increased the frequency of yellow spots much more than dark green spots or twin spots. Light green spots were observed on y11y11 plants. Azaserine and DON induce somatic crossing over, point mutation and segmental loss as major effects.

Azaserine↗

PubMed1995

Protein kinase cascade activated by mechanical stress in cardiocytes: possible involvement of angiotensin II.

Mechanical stress induces cardiac hypertrophy and expression of specific genes in the cardiac myocytes. External stimuli are generally transduced into the nucleus through the activation of a protein kinase cascade. We have previously shown that stretching cardiomyocytes stimulates the activity of protein kinase C (PKC), mitogen-activated protein (MAP) kinase and S6 protein kinase. In the present study, we examined two other kinases, Raf-1 kinase and MAP kinase kinase, which are supposed to lie between PKC and MAP kinase in the protein kinase cascade. Stretching cardiocytes by using the in vitro system induced hyperphosphorylation of Raf-1 kinase and activation of MAP kinase kinase. The protein kinases activated by mechanical stress are similar to those activated by growth factors. We examined the possible involvement of angiotensin II (Ang II) in the protein synthesis and gene expression induced by mechanical stress. CV11974, an Ang II-receptor antagonist, partially suppressed the increases in amino acid incorporation, c-fos gene expression and MAP kinase activity induced by stretching. These results suggest that a variety of protein kinases are activated by mechanical stress and that locally produced Ang II may in part play important roles in converting mechanical stimuli into biochemical signals.

Angiotensin II↗