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Biomedical subjects

Y Miyata

Publications and source records attributed to Y Miyata.

At least 73 records · Page 4Linked to original sources
PubMed2000

Reversibility of serum NH3 level in a case of sudden onset and rapidly progressive case of type 2 citrullinemia.

A 48-year-old male presented with an acute change in mental status due to a marked elevation of plasma NH3 and was diagnosed with citrullinemia with amino acid analysis of blood. Hemodialysis and hemodiafiltration were performed, but serum chemical analysis did not show any improvement which led us to terminate dialysis following intensive care for 3 days. Surprisingly, NH3 level had decreased by 6 days after admission, coinciding with normalization of the size of the pupils. Since spontaneous remission had never been discussed, we discuss this relatively rare, but clinically significant entity with regard to its acute phase management and its potential reversibility.

Ammonia↗
PubMed2000

[A case of teratoma in both the mediastinum and the intrapulmonary system].

A rare case of mature teratoma in both the mediastinum and the intrapulmonary system is presented. A 30-year-old male was admitted to our hospital due to tumor masses in the mediastinum and the left lung. We performed mediastinal tumor resection and left upper partial lobectomy. Neither tumor communicated with each other. Pathological findings revealed teratoma in the mediastinal lymph node and the intrapulmonary system including no malignant cells in either tumor. In this case, because metastasis and perforation were negative, we proposed that both tumors occurred at the same time in the early embryo.

Adult↗
PubMed2000

[Development of arterial thrombus of Mucorales hyphae during deferoxamine therapy in a patient with aplastic anemia in transformation to myelodysplastic syndrome].

A 58-year-old woman with a diagnosis of aplastic anemia had been treated with anabolic steroid for mild anemia in 1984. In May 1995, pancytopenia progressed and the patient became dependent on red blood cell transfusions. Chromosome analysis of bone marrow cells revealed trisomy 8 and the patient was thought to have aplastic anemia in transformation to myelodysplastic syndrome. In July 1996, deferoxamine was administered for iron overload. The patient was admitted because of pneumonia on July 31, 1998. Chest computed tomograms showed arteriothrombus of the right pulmonary artery and pulmonary mycosis. Although an antifungal agent was administered, the patient experienced respiratory failure and eventually died of hypovolemic shock due to gastric bleeding from a Dieulafoy ulcer. Autopsy revealed arteriothrombus of hyphae of Mucorales in the right pulmonary artery and right renal artery branch. Cases of mucormycosis occurring in dialysis patients receiving deferoxamine have recently appeared in the literature. Deferoxamine may be a risk factor for mucormycosis. Deferoxamine has been also used in the treatment of iron overload patients with aplastic anemia. Four cases of mucormycosis developing in such patients have been reported in Japan including this case. There may be a relationship between mucormycosis and deferoxamine in patients with aplastic anemia.

Anemia, Aplastic↗
PubMed2000

[Correlation between response and survival].

The true endpoints of cancer chemotherapy have to be prolongation of survival, palliation of symptoms, or improvement of quality of life in cancer patients, while the response rate is considered to be a surrogate endpoint. When conducting a phase III trial, not only the response rate but also data on survivals in the phase II study should be taken into consideration. New response evaluation criteria and various objective markers in analyzing survival have been developed recently. Our data on chemotherapy for gastrointestinal malignancies reveal correlations between CR cases and survival prolongation among esophageal cancer patients treated with chemoradiotherapy, and between responder and survival prolongation in gastric cancer patients treated with chemotherapy. A review of the literature might reveal a correlation between response and survival prolongation in colorectal chemotherapy patients, though our data did not support such a correlation. At present, it is necessary to recognize that "evidence" should be based on the results of randomized phase III trials with large sample sizes and good quality assurance other than the response rates in phase II trials.

Antineoplastic Agents↗
PubMed2000

[In vitro growth and clinical response of leukemia cells to macrophage colony-stimulating factor (M-CSF) and granulocyte colony-stimulating factor (G-CSF) in acute leukemia].

The in vitro growth and clinical response of leukemia cells to macrophage colony-stimulating factor (M-CSF) and granulocyte colony-stimulating factor (G-CSF) were studied in 24 patients with acute leukemia. Among cases of acute myelogenous leukemia, a positive response to M-CSF (stimulation index > or = 2.5) was seen in 27.3% of the cases, and a significantly higher response rate (81.8%) was seen following G-CSF treatment of leukemia cells in vitro. In cases of acute monocytic leukemia, M-CSF showed a higher stimulating index than that observed for non-monocytic leukemia. G-CSF was administered in 19 cases and M-CSF in 5 cases after chemotherapy, and none of the patients showed leukemia cell proliferation in vivo. There was no correlation between in vitro test results and clinical response of leukemia cells to the CSFs administered.

Adult↗
PubMed2000

[Concurrent chemoradiotherapy for T4 and/or M1 LYM squamous cell carcinoma of the esophagus].

A phase II study was conducted to investigate the efficacy and feasibility of chemoradiotherapy for locally advanced carcinoma of the esophagus. Fifty-four patients with clinical T4 and/or M1 LYM squamous cell carcinoma of the esophagus were enrolled. Patients received protracted infusions of fluorouracil 400 mg/m2/24 hours on days 1 to 5 and 8 to 12, 2-hour infusions of cisplatin 40 mg/m2 on days 1 and 8, and concurrent radiotherapy at a dose of 30 Gy in 15 fractions over 3 weeks. Filgrastim was prophylactically administered to 35 patients. This schedule was repeated twice every 5 weeks, for a total radiation dose of 60 Gy followed by two courses of fluorouracil (800 mg/m2/24 hours for 5 days) and cisplatin (80 mg/m2 on day 1). There were 36 patients with T4 disease and 33 with M1 LYM. Forty-nine patients (91%) completed the chemoradiotherapy segment. The 18 patients (33%) who achieved a complete response included nine (25%) of the 36 with T4 disease and nine (50%) of the 18 with non-T4 disease. Major toxicities were leukopenia and esophagitis; there were four (7%) treatment-related deaths. Prophylactic filgrastim reduced the incidence of grade 3 or worse leukopenia without improving dose-intensity or response. With a median follow-up duration of 43 months, median survival time was 9 months. The 3-year survival rate was 23%. Despite its significant toxicity, this combined modality seemed to have curative potential even in cases of locally advanced carcinoma of the esophagus.

Adult↗
PubMed1999

Distantly related cousins of MAP kinase: biochemical properties and possible physiological functions.

MAP kinases have been established to be key regulators of cellular signal transduction systems and are conserved from baker's yeast to human beings. Until now, three major types of mammalian MAP kinases (ERK, p38, and JNK/SAPK) have been reported and extensively studied. Advancement of genomic research as well as homology cloning techniques has revealed that there are several other protein kinase families that are structurally modestly related to those conventional MAP kinases. Indeed, most of them possess the TXY motif characteristic to MAP kinases in their activation loop, and can be regarded as members of the MAP kinase superfamily, yet some of them show closest overall similarity to Cdks. These kinases, all of mammalian origin, include MAK, MRK, MOK, p42KKIALRE, p56KKIAMRE, NLK, DYRK/Mnb, and Prp4. Although most of their physiological roles remain unknown, recent progress starts shedding some light on their functions.

Amino Acid Sequence↗
PubMed1999

A strategy to make constitutively active MAP kinase by fusing with constitutively active MAP kinase kinase.

Classical mitogen-activated protein kinases (MAPKs) play a pivotal role in a variety of cellular signal transduction pathways. MAPKs are activated by phosphorylation at specific threonine and tyrosine residues catalyzed by upstream MAPK kinases (MAPKKs). Mutations of these two activation phosphorylation sites into acidic amino acids, however, do not convert MAPKs into constitutively active forms. Here, we report an approach to make a molecule with constitutive MAPK activity. The nuclear export signal-disrupted, constitutively active MAPKK was fused to the N-terminal end of wild-type MAPK. When the resulting fusion protein was expressed in Escherichia coli, the MAPK moiety became phosphorylated and the fusion protein was constitutively active as MAPK. Moreover, when expressed in mammalian cultured cells, the fusion protein was also activated as MAPK and was able to induce marked morphological changes in NIH-3T3 cells. These results suggest that the fusion protein can work as constitutively active MAPK and that this approach may be applicable to other members of the MAPK family to make constitutively active forms.

3T3 Cells↗
PubMed1999

Auditory event-related potentials in an amnesic patient with a left temporal lobe lesion.

We studied auditory event-related potentials (ERPs) in correlation with Rey's auditory verbal learning test (AVLT) in an amnesic patient with a left temporal lobe lesion. On the AVLT, the number of words recalled was limited to immediate memory capacity (nine words) throughout five trials, and recall after interference was remarkably decreased. In the ERPs, the P300 component was elicited normally, but no N400 component was apparent. Present findings suggest that these two ERP components may be associated with independent processes and support the view that the N400 may index a neural process involved in transfer of information from immediate memory to long-term storage.

Amnesia, Anterograde↗
PubMed1999

Mutagenicity of 4-nitroquinoline 1-oxide in the MutaMouse.

As part of a collaborative study, the Mammalian Mutagenesis Study Group (MMS), a sub-organization of the Environmental Mutagen Society of Japan (JEMS) conducted mutagenicity tests in MutaMouse. Using a positive selection method, we studied the organ-specificity and time dependence of mutation induction by 4-nitroquinoline 1-oxide (4NQO). A single dose of 4NQO was administered intraperitoneally (7.5 or 15 mg/kg) or orally (200 mg/kg) to groups of male mice. On days 7, 14 and 28 after treatment, we isolated the liver, kidney, lung, spleen, bone marrow, testis and stomach in the intraperitoneal administration experiment and the liver, lung, bone marrow, testis and stomach in the oral administration experiment. In addition, we performed the peripheral blood micronucleus test to evaluate clastogenicity. In the mice treated intraperitoneally at 7.5 mg/kg, we found increased mutant frequency (MF) only in the lung, where the MF did not vary with expression time. In the mice treated at 15 mg/kg, we found increased MF in the liver, bone marrow and lung. In orally treated mice, the MF was high in the lung and liver and very high in the bone marrow and stomach while the increase in the testis was negligible. As the expression time was prolonged, the MF tended to increase in the liver, decrease in the bone marrow, and remain stable in the lung, testis and stomach. The incidence of micronucleus induction in peripheral blood cells was significantly increased (p<0.01) in the 4NQO groups when compared with the vehicle control group by intraperitoneal treatment. Thus, these assay systems appeared to be of use in detecting not only genetic mutation but also chromosomal aberration.

4-Nitroquinoline-1-oxide↗
PubMed1999

Memory in patients with subcortical infarction--an auditory event-related potential study.

Event-related potentials (ERPs) were recorded from 21 patients with subcortical infarction (mean age, 62.1 years) and 14 normal control subjects (mean age, 62.7 years) as they listened to lists of words or pronounceable non-words. Some words were repeated immediately after initial presentation (lag 0), while others were repeated after five intervening words (lag 5), or after 2 to 4 min (lag 11-77). The subjects were asked to push a button upon hearing the occasional non-words. The Auditory-Verbal Learning Test (AVLT) also was administered to the patients to examine explicit memory. The mean N400 amplitude, appearing between 300 and 800 ms after the stimulus, was smaller in patients with subcortical infarction than in control subjects. The N400 in response to repeated words at lags 0, 5 and 11-77 was attenuated for both the patient and control groups. On the AVLT the total number of recalled words and number of words after interference were significantly decreased in patients relative to controls, while recognition was relatively preserved. The results suggest that lexical processing and retrieval mechanism of explicit memory are disturbed in patients with subcortical infarction, but implicit memory measured by this N400 paradigm is relatively preserved.

Acoustic Stimulation↗
PubMed1999

Event-related potentials reveal memory deficits in Parkinson's disease.

To evaluate whether patients with Parkinson's disease (PD) exhibit deficits in memory tested indirectly, we measured event-related potentials (ERPs) in 23 patients with nondemented PD and 14 age-matched control subjects. The auditory N400 component was measured during an indirect repetition priming paradigm. Some words were repeated immediately after initial presentation (lag 0), while others were repeated after five intervening words (lag 5) or at lags 11-77. Subjects were required to push a button to the occasional nonwords (targets). The N400 amplitudes were quantified in latency window between 300 and 800 ms for the different conditions. The N400 amplitudes for the first presentation were significantly lower in PD patients than controls for both words and nonwords. The N400 in the control group was attenuated for lag 0, lag 5, and lags 11-77 repetitions, while the attenuation in PD patients was noted only for lag 0 repetition. The data suggest that memory assessed in this fashion is impaired in PD patients.

Aged↗
PubMed1999

Video-assisted thoracoscopic surgery does not deteriorate postoperative pulmonary gas exchange in spontaneous pneumothorax patients.

OBJECTIVES: Video-assisted thoracoscopic surgery (VATS) is generally recognized as a less invasive method than thoracotomy. However, the influence of VATS on postoperative pulmonary gas exchange has yet to be evaluated. METHODS: Thirty eight patients with spontaneous pneumothorax were randomized into bullectomy by VATS (n = 20) or axillary thoracotomy (n = 18). Gas exchange was assessed by using hot wire mass spectrometer, and blood gas analysis preoperatively and postoperatively at 1, 3, 6, 12, 24, and 48 h and on days 4 and 6. Post operative pain control was managed by continuous epidural morphine injection and administration of diclofenac sodium orally or suppository. Postoperative atelectasis was assessed by daily chest roentgenograms. RESULTS: VATS patients had continuously higher PaO2 than axillary thoracotomy at 12, 48 h and day 4 postoperatively (P < 0.05). Alveolar-arterial oxygen tension gradient in VATS patients was significantly less than that in patients with axillary thoracotomy from the 6th h throughout to the 4th day postoperatively (P < 0.01). Use of postoperative analgesics and the incidence of peripheral atelectasis were more frequent in patients with axillary thoracotomy. CONCLUSIONS: Bullectomy via VATS was less deleterious to pulmonary gas exchange. Axillary thoracotomy caused worsening of gas exchange postoperatively due to incisional pain, chest wall deformity, and peripheral atelectasis.

Adult↗
PubMed1999

The bioavailability of magnesium from Wakame (Undaria pinnatifida) and Hijiki (Hijikia fusiforme) and the effect of alginic acid on magnesium utilization of rats.

The bioavailability of magnesium from Wakame and Hijiki, and the effects of alginic acid on absorption of dietary magnesium were examined in five groups of rats fed either control, Wakame, Hijiki, AW (containing the same amount of alginate as in the Wakame) and AH (containing the same amount of alginate as in the Hijiki) diets, and animals fed a low magnesium diet (LMg) (twentieth amount of magnesium in the original mineral mixtures as the control). Food intake and body weight gain were decreased by adding sodium alginate to the diets. A large amount of calcium accumulated only in the kidneys of the rats fed the LMg diet. Serum magnesium concentration decreased only in the LMg group. The magnesium content in the defatted left femurs did not differ between the control and Wakame fed animals and also among the animals eating Wakame, Hijiki and AW diets. The breaking force of the right femurs did not differ among all the groups except the LMg group. The ratio of apparent magnesium absorption (%) of the control, LMg, Wakame, Hijiki, AW and AH groups was 82.2, 72.7, 66.9, 50.8, 69.3 and 54.2 in the first experimental period, and was 75.3, 52.1, 57.7, 46.9, 62.6 and 60.5 in the second experimental period, respectively. It was clear that the bioavailability of magnesium in the Wakame fed rats was higher than in those eating the Hijiki. Large amounts of sodium alginate lowered magnesium absorption from the diet.

Alginates↗