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Biomedical subjects

T Nemoto

Publications and source records attributed to T Nemoto.

At least 127 records · Page 7Linked to original sources
PubMed1995

Effects of GABAergic drugs on the recovery of reflex potentials after spinal cord ischemia in cats.

Effects of GABAergic drugs on the recovery of reflex potentials after spinal cord ischemia were examined in anesthethized spinal cats. Monosynaptic reflex (MSR) and polysynaptic reflex (PSR) potentials, elicited by electrical stimulation of the tibial nerve in spinal cats, were recorded from the lumbo-sacral ventral root. The spinal reflex potentials were immediately depressed by occlusion of the thoracic aorta and the bilateral mammary arteries for 10 min. The potentials recovered gradually to the control level within 90 min after reperfusion. Pretreatment with bicuculline (0.3 mg/kg, i.v.), a GABA antagonist, or semicarbazide (200 mg/kg, i.v.), an inhibitor of GABA synthesis, accelerated the recovery of PSR potentials after the removal of the arterial occlusion. In contrast, pretreatment with aminooxyacetic acid (10 mg/kg, i.v.), an inhibitor of GABA degradation, retarded the recovery of PSR potentials, and this effect was overcome by the addition of the opioid antagonist naloxone (10 mg/kg, i.v.). These results suggest that the GABAergic system retards the recovery of PSR potentials after a brief spinal cord ischemia, which can be antagonized by naloxone.

Animals↗
PubMed1995

Reduction of androgen receptor mRNA concentration by testosterone in mouse submandibular gland.

In this study, we examine the effect of testosterone on the steady-state concentration of androgen receptor (AR) mRNA of mouse submandibular gland. Northern blot analysis showed the expression of an AR-specific 10-kb transcript in the submandibular glands of both sexes. Quantitative analysis was done by means of reverse transcription-polymerase chain reaction (RT-PCR) with a non-radioactive label of digoxigenin. The RT-PCR demonstrated that the steady-state of AR mRNA concentration was less in males than in females. Moreover, AR mRNA increased in the castrated male mice, while the administration of testosterone reduced the AR mRNA in female mice. In conclusion, the amount of AR mRNA in mouse submandibular gland is reduced by androgen.

Animals↗
PubMed1995

[Study on human eye movements induced by prolonged eye closure and lid opening--report 2. Closing and opening of eyelids].

The eye movement during prolonged eye closure and the following eye opening has not been studied precisely. In the present study we evaluated the eye movement during prolonged eye closure and the following eye opening using a magnetic search oil method. In a bright room, the exact moment of recognizing a visual target during eye opening could not be determined. Therefore, other conditions were used to elucidate the precise relationship between the presence and lack of visual input during eye opening. Eye movement during eye opening was accomplished in three phases. The first phase had rapid movements like visually guided saccades toward the imaged target. The second phase had slow movements and drift toward the imaged target, and the final eye position was reached within 3 degrees from the target from 5 different gaze directions. The third phase was final visually evoked corrective saccades and the subjects found the target. We discuss the origin of these eye movements.

Adult↗
PubMed1995

[Clinical significance of late peak formation of creatine kinase in patients with acute anterior myocardial infarction after successful reperfusion].

Generally, the time from the onset of acute myocardial infarction (MI) to peak serum creatine kinase (CK) activity is short in patients with acute MI after successful reperfusion. However, in some patients peak CK is observed more than 16 hours after the onset of acute MI despite successful reperfusion. To elucidate the clinical characteristics of patients with late peak CK, CK activity was examined in 55 patients (mean age: 57.5 +/- 10.2 years) with initial acute anterior MI after successful reperfusion. All patients had coronary reflow (TIMI grade 3) within 6 hours after onset of acute MI and no subsequent reocclusion for at least 14 days. The patients were classified into two groups: group E, 41 patients with peak CK observed within 16 hours of onset of acute MI (mean 8.7 hours), and group L, 14 patients with peak CK observed after more than 16 hours (mean 18.7 hours). Although there were no significant differences in the time elapsed between the two groups, the mean peak CK was significantly lower in group L than in group E (2,179 +/- 861 vs 5,379 +/- 2,569 mU/ml, p < 0.01). Well-developed collateral supplies to the infarcted area before reperfusion were observed more frequently in group L (79% vs 24%, p < 0.01). The sum of ST elevation in all leads before reperfusion was lower in group L (12 +/- 7 vs 20 +/- 12 mm, p < 0.01) and additional ST elevation during reperfusion was not observed in group L (0% vs 56%, p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[Study on human eye movements induced by blinks--report 1. Three kinds of blinking].

The eye movement associated with blinking was studied with a magnetic search coil method. Lid movements and eye movements associated with spontaneous blinks, voluntary blinks, and reflex blinks induced by puffs of air or flashes of light were analysed. Eye movements associated with spontaneous blinks and voluntary blinks had initial downward and adducted movements followed by upward and abducted movements of the eyeball. Reflex blinks initially showed the same downward and adducted movements, but upward and abducted movements were not constantly obtained in given subjects. The velocity-amplitude ratio was equal among the three kinds of blinks in both horizontal and vertical movements. The velocity-amplitude ratio of the eye movements associated with blinks and visually-guided saccadic eye movements was compared. The horizontal and vertical eye movements associated with blinks were slower than those of saccadic eye movements in the same subject. Therefore, the eye movements associated with the blinks may have a different neural mechanism in the brain from that of the saccadic eye movement system.

Adult↗
PubMed1995

[Transformation into chronic myelomonocytic leukemia in a patient with primary myelofibrosis associated with severe hypoplasia: report of an autopsy case].

A 70-year-old male was admitted because of anemia in September 1989, and primary myelofibrosis was diagnosed based on the presence of leukoerythroblastosis, a normal chromosomal analysis and pathological findings of fibrosis in bone marrow. Although he was anemic, he did not require any treatment for two years. Then his hematological status deteriorated to severe pancytopenia, and the marrow biopsy revealed marked hypoplasia with fatty replacement and scattered fibrosis. He was treated with metenolon without success and frequent transfusion of packed red cell was required. This hypoplastic status continued for seven months. In May 1992 his WBC count increased gradually with monocytosis. The marrow was filled with various stages of monocytes, with almost no fibrosis remaining. The chromosomal analysis was repeated but disclosed no abnormalities, consistent with the negative result of BCR-ABL rearrangement investigated by the RT-PCR method. One month later, when the patient died of multiple cerebral bleeding and infection, the leukocyte count exceed 90,000/microliters. It is known that major causes of death for patients with primary myelofibrosis are infection, bleeding, cardiac trouble and transformation to leukemia. We describe a case of myelofibrosis who developed to chronic myelomonocytic leukemia following severe aplastic phase.

Aged↗
PubMed1995

[Clinical significance of inverted T-waves during the acute phase of myocardial infarction in patients with myocardial reperfusion].

The relationship between the time course of inverted T-waves during the acute phase and infarct size and left ventricular (LV) function was studied in 46 patients (mean age: 57.3 +/- 9.7 years) with reperfused first anterior wall acute myocardial infarction (MI). All patients had coronary reflow within 6 hrs after the onset of MI and were without subsequent reocclusion for at least 14 days. The T-wave inverted progressively and rapidly with maximum depth between 26 and 60 hrs (mean time: 37.1 +/- 12.4 hrs). A significant correlation was found between the maximum T-wave depth (T-peak) in all patients and peak CPK, left ventricular ejection fraction (LVEF), regional wall motion, % abnormally contracting segment (%ACS), end-diastolic and end-systolic volume indices (EDVI,ESVI) at day 14 after the onset of MI (p < 0.05). T-wave inversion within 24 hrs after onset of MI was observed in 43 patients (93%). There were significant correlations between the depth of T-wave inversion occurring in patients 24 hrs after onset of MI (T24) and peak CPK, LVEF, regional wall motion, % ACS, EDVI, and ESVI at day 14 (p < 0.05). The sensitivity and specificity for patients with EDVI > 87.0 ml/m2 at day 14 increased by more than 20% over normal values, predicted by a T24 of 3.0 mm or less, were 94% and 93%, respectively. The sensitivity and specificity for patients with EF < 40% at day 14 predicted by a T24 of 3.0 mm or less, were 90% and 75%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[A new system for classifying bronchial asthma].

Classification of bronchial asthma with Rackemann's system or Swineford's system is too simple to be clinically useful. We developed a new system for classifying patients with asthma. Patients were assigned a "0" or a "1" for each of five criteria: the presence or absence of (1) steroid dependence, (2) allergy, and (3) sensitivity to aspirin, and whether or not their asthma was judged to be (4) hereditary and (5) infectious. For example, patients who were sensitive to aspirin and whose asthma was judged to be of the infectious type were classified as 00101. A total of 434 patients with asthma were studied (185 males and 249 females, ranging in age from 10 to 93 years). The patients were classified into 32 subtypes (shown in an accompanying table), and the data were compared to the results of classification by other methods. The present system may be more useful than those of Rackeman or Swineford, because it takes heredity and sensitivity to aspirin into account. A total of 103 patients could not be classified by Swineford's system: those in classes 00000, 00010, 00100, 00110, 10000, 10010, 10100, and 10110. We expect this new system for classifying bronchial asthma to be clinically useful.

Adolescent↗
PubMed1994

Changes of cell cycle-regulating genes in interferon-treated Daudi cells.

Interferon (IFN) modulates the expression of several genes and some of them are considered to be responsible for the inhibition of cellular growth. However, the alterations of cell cycle-regulating genes produced by IFN still remain unclear. Accordingly, we studied the expression of cell cycle-regulating genes during IFN-induced growth arrest. Cell cycle synchronized and unsynchronized Daudi Burkitt lymphoma cells were treated with IFN. Both the cell cycle distribution and the expression of cell cycle-regulating genes (cdk2, cdc2, cyclins A, B, C, D3, cdc25, and wee 1) were studied by flow cytometry and by Northern blot hybridization or the reverse-transcription polymerase chain reaction, respectively. Treated cells passed through the first G1 phase and gradually accumulated in the following G1 phase. Expression of cyclins A, B, and D3 oscillated along with the cell cycle progression in control cells, and the alterations of cyclin B expression were especially prominent. Both cdc2 and cdk2 also showed changes, but these were not so distinct as observed with cyclin B. Expression of cdc25 and wee1 was little affected by cell cycle progression. In IFN-treated cells, expression of cyclins A and B were down-regulated, while that of cyclin C was not. Cyclin D3 expression was also down-regulated at 48 h, followed by an increase at 72 h. Expression of both cdc2 and cdk2 was down-regulated, especially that of the later. Wee1 expression was down-regulated by IFN but, the expression of cdc25 remained stable. These findings suggest that the modulation of cell cycle-regulating genes, particular by cyclin A and cdk2, plays an important role in IFN-induced cellular growth arrest.

Base Sequence↗
PubMed1994

[A case of idiopathic hyperaldosteronism with normal plasma aldosterone concentrations for 5 years after onset: a 12-year follow-up study].

We report a 54-year old man diagnosed as idiopathic hyperaldosteronism (IHA) at least 12 years after the onset. At the age of 42, he showed hypertension (162/100mmHg), hypokalemia, metabolic alkalosis, low plasma renin activity (PRA) and normal plasma aldosterone concentration (PAC) in a supine posture. Both PRA and PAC were elevated after a 2-hour ambulation following furosemide (60mg) injection. Since the accumulation of radioactivity following 131I-aldosterol injection with combined administration of dexamethasone was equally detected in both adrenal areas, he was diagnosed as low-renin essential hypertension (LREH). Blood pressure (BP) decreased to the normal range after treatment with nifedipine (40mg/day). At the age of 47, however, BP was hypertensive (164/106mmHg) serum potassium (K) level was normal. Although PAC was normal in a supine posture, it increased after a 2-hour ambulation following furosemide (60mg) injection. PRA after the stimulation was still suppressed despite the increase in PAC. At the age of 54, BP was 172/94mmHg. Serum K level was 3.4mEq/L. PRA was suppressed below 0.1 ng/ml/hr, while PAC was above the normal range (170pg/ml) in a supine posture. Serum cortisol and urinary excretion of 17-OHCS and 17-KS were within normal limits. PRA was still suppressed below 0.1 ng/ml/hr after a 2-hour ambulation following furosemide (60mg) injection, but PAC was markedly increased (330pg/ml). There was a diurnal rhythm of aldosterone, which was parallel to that of ACTH.(ABSTRACT TRUNCATED AT 250 WORDS)

Aldosterone↗
PubMed1994

Changes of G1 cyclins, cdk2, and cyclin A during the differentiation of HL60 cells induced by TPA.

Differentiation induction by 12-o-tetradecanoyl 13-acetate (TPA) results in the growth arrest of HL60 cells in the G1 phase. However, little is known about the changes of cell cycle-regulating genes during this differentiation process. We investigated the changes of mRNA for various cyclins (A, C, D1, D2, D3 and E) and cdk2. Synchronized HL60 cells began to proliferate immediately after release from cell cycle block and cell cycle synchrony was obvious until the second S phase. TPA-treated cells accumulated in G1 phase within 24 h and most of the cells were arrested in this phase at 36 h. The expression of cyclins and cdk2 was studied by Northern blot hybridization of the reverse-transcription polymerase chain reaction (RT-PCR). TPA treatment altered the expression of all genes studied. The expression of cdk2 and cyclin A mRNA was markedly down-regulated. Cyclin E mRNA expression was also prominently down-regulated from 12 h to 36 h, at which time a second increase of its expression was observed in control cells. In contrast, the expression of cyclin D1 mRNA was induced by TPA, while its expression in control cells was undetectable by Northern blot hybridization throughout the cell cycle. Cyclin C expression was faint and fluctuated irrelevant of cell cycle, but its expression in both control and TPA-treated cells was higher than at baseline. Cyclin D2 expression remained stable in control cells and TPA treatment resulted in slight down-regulation at 12 h, but no difference was observed after 24 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMed1994

neu proto-oncogene mutation is specific for the neurofibromas in a N-nitroso-N-ethylurea-induced hamster neurofibromatosis model but not for hamster melanomas and human Schwann cell tumors.

Point mutations of the transmembrane domain coding region of the neu proto-oncogene in N-nitroso-N-ethylurea-induced hamster neurofibromas were found at high frequency (93%; 14 of 15). They involved codons 659 as well as 658, the latter not having been reported previously in rat tumors. The mutational change was seen even in the early stage neurofibroma. On the other hand, no mutations were detected in melanomas or Wilms' tumors induced in the same N-nitroso-N-ethylurea-treated animals, even when the melanomas demonstrated extensive schwannian differentiation. Moreover, any human Schwann cell tumors including neurofibroma, schwannoma, and malignant schwannoma did not show the mutation of c-erbB-2 gene (0 of 34), which is homologous to the hamster neu. Since high expression of neu mRNA is evident in the hamster Schwann cell at the late gestational and neonatal stages, transplacental administration of N-nitroso-N-ethylurea is considered to interact directly to carcinogenesis of the hamster Schwann cell through neu gene mutation.

Amino Acid Sequence↗
PubMed1994

Cardiomyopathy and angiopathy in patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes.

In four patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes (MELAS) in which mutated mitochondrial deoxyribonucleic acid was seen, hypertrophic cardiomyopathy and angiopathy was demonstrated by echocardiography, dipyridamole stress scintigraphy, and cardiac catheterization. On stress scintigraphy with dipyridamole, three patients showed hypoperfusion in the early image and a "filling-in" pattern in the late image. However, coronary angiography did not demonstrate narrowing of the large vessels in these patients. Light and electron microscopy of endomyocardial biopsy specimens indicated abnormal mitochondria, with marked increase in the number and size of mitochondria in endothelium. Modified Gomori's trichrome staining in biopsied endomyocardial specimens revealed a red-purple deposit similar in appearance of the ragged-red fibers in skeletal muscle, a characteristic finding of mitochondrial disease. Deterioration of complex I in the mitochondrial electron transfer system, which is widely observed in various mitochondrial diseases, appeared in biopsied skeletal muscle of our patients, indicating deficiency of some subunits of complex I. These results indicate that mitochondrial diseases such as MELAS show not only cardiomyopathy but also angiopathy. We speculate that proliferation of mitochondria leads to narrowing of the lumen of arterioles, which might be responsible for the ischemic findings observed scintigraphically.

Adolescent↗
PubMed1994

Dimerization characteristics of the DNA- and steroid-binding domains of the androgen receptor.

The DNA-binding domain (DBD) of the androgen, mineralocorticoid, and glucocorticoid receptors and the steroid-binding domain (SBD) of the androgen receptor (AR) were expressed separately as fusion proteins with glutathione-S-transferase (GST) in Escherichia coli. Native polyacrylamide gel electrophoresis and gel exclusion HPLC demonstrated that the GST-ARDBD fusion protein was present as a dimer. On the other hand, the GST-ARSBD fusion protein formed a high-molecular weight oligomer, which seemed to be formed by two separate interactions, i.e. GST-GST and ARSBD-ARSBD between the fusion molecules. These findings strongly suggest that ARSBD has a potent ability to form a homodimer and that ARDBD does not. GST-ARDBD specifically interacted with the glucocorticoid response elements of the mouse mammary tumor virus long terminal repeat (GREMMTV). Cleavage of the fusion protein by thrombin abolished the binding, while the nonspecific DNA-cellulose binding ability was retained. Therefore, the dimeric configuration of GST-ARDBD, even if accomplished through the interaction with the GST moiety, is needed for high-affinity binding to the response element. The binding of GST-ARDBD to GREMMTV was strongly competed by the glucocorticoid response element of rat tyrosine aminotransferase gene, followed by the androgen response element of the rat probasin gene. A palindromic thyroid response element showed no competition. Unexpectedly, no apparent different in the binding affinity to these response elements was observed among the DBDs of androgen, mineralocorticoid and glucocorticoid receptors.

Amino Acid Sequence↗
PubMed1994

Patterns of cocaine use and HIV infection among injection drug users in a methadone clinic.

To investigate patterns of cocaine use, a total of 440 injection drug users (IDUs) in two consecutive cohorts were recruited from a methadone maintenance program in New York City. IDUs who had injected cocaine more frequently during the prior year were more likely to be found HIV positive than IDUs who had injected cocaine less frequently, even after controlling for age, gender, and ethnicity. The study investigated noninjecting cocaine use among IDUs, such as snorting and smoking cocaine, which is often overlooked in epidemiological research investigating the relationship between HIV infection rate and drug use behaviours among IDUs. This study revealed that older IDUs were more likely to use IV cocaine and speedball, whereas younger IDUs were more likely to use crack or snort cocaine. In the 1987 cohort, after statistically controlling for age, analyses revealed that Hispanic IDUs snorted cocaine more frequently than other groups, and that black female IDUs used crack more frequently than other groups. Future research should investigate whether these crack and cocaine users, particularly black and Hispanic female IDUs, have changed their drug behaviors because of an awareness of the high risk of IV drug use for HIV infection, or whether they have started using these drugs as stepping stones for future IV cocaine and speedball use.

Adult↗