Search PubMed⌕ Search

Biomedical subjects

K Goto

Publications and source records attributed to K Goto.

At least 415 records · Page 23Linked to original sources
PubMed1995

A severe muscular dystrophy patient with an internally deleted very short (110 kD) dystrophin: presence of the binding site for dystrophin-associated glycoprotein (DAG) may not be enough for physiological function of dystrophin.

We report a 4-yr and 5-month-old boy with severe clinical features of an early-onset Duchenne muscular dystrophy, who had a very short (110 kDa) dystrophin at the sarcolemma. The patient had a large deletion (exons 2-44) of the dystrophin gene which was predicted to cause a reading frame shift. Sequence analysis of dystrophin mRNA in muscle revealed an alternatively spliced gene product from exons 1 to 51 that caused restoration of the reading frame, in addition to an mRNA corresponding to the DNA deletion. A consistent result was obtained by immunocytochemical analysis of muscle; i.e. positive staining for dystrophin at the sarcolemma using antibodies against the C-terminus, cysteine-rich region and last three of 24 repeat units of the central rod-domain, but not for the remaining antibodies for dystrophin that recognize the N-terminal and proximal rod-domains. Immunostaining for dystrophin-associated glycoproteins (DAGs: 43 and 50 K) and merosin were preserved. Utrophin staining was positive but fainter than other DMD muscles. These results suggest that an extremely short dystrophin lacking the entire actin-binding site in the N-terminus cannot function properly even if the protein possesses the putative DAG-binding cysteine-rich and the C-terminal domains, and still has an ability to associate with sarcolemmal membrane.

Base Sequence↗
PubMed1995

Malignant hyperthermia in a patient with Becker muscular dystrophy: dystrophin analysis and caffeine contracture study.

We present a 17-year-old boy with Becker muscular dystrophy (BMD) who developed hyperthermia and heart failure after general anesthesia. He presented clinical features of malignant hyperthermia (MH), and had masseter spasm and elevated body temperature (38.7 degrees C) with very high serum CK activity (107,000 IUl-1). Dystrophin tests confirmed a clinical diagnosis of BMD in the patient, i.e. faint and patchy immunostaining pattern of skeletal muscle, truncated dystrophin protein and a deletion of exons 3 and 4 of the dystrophin gene. To inquire into the mechanism of MH associated in the patient, we tested caffeine contracture reaction by the skinned fiber method. We found an increased sensitivity to caffeine only in type 1 muscle fibers. The rate of Ca(2+)-induced Ca2+ release (CICR) was normal, suggesting that the mechanism of "MH" observed in our patient with BMD is not the same as that of classical MH. A possible mechanism might be related to derangements of the sarcoplasmic reticulum membrane in BMD, which sensitize the membrane to caffeine or other agents.

Adolescent↗
PubMed1995

Interaction between pregnancy-induced bioactive peptides and the placental proteases.

Studies have shown that placental proteases metabolize vasoactive peptides, possibly derived from the fetus, and protect the exchange of peptide hormones across the placenta in order to maintain feto-placental homeostasis. Changes in maternal serum protease activities were useful for monitoring pre-eclampsia and predicting the onset of labour. The study showed that possible role of oxytocinase in the maintenance of gestation and the possible involvement of angiotensinase in the attenuated pressor responses to angiotensin II during pregnancy, respectively. In addition, the ratio of peak systolic over least diastolic pressure (S/D) of uterine or umbilical artery assessed by the Doppler technique was closely correlated with the concentrations of maternal serum proteases in pre-eclampsia, which suggested that placental proteases might control utero-placental circulation via the regulation of concentrations of vasoactive peptides in uteroplacental circulation.

Cystinyl Aminopeptidase↗
PubMed1995

Is the cell division cycle gated by a circadian clock? The case of Chlamydomonas reinhardtii.

Circadian oscillators are known to regulate the timing of cell division in many organisms. In the case of Chlamydomonas reinhardtii, however, this conclusion has been challenged by several investigators. We have reexamined this issue and find that the division behavior of Chlamydomonas meets all the criteria for circadian rhythmicity: persistence of a cell division rhythm (a) with a period of approximately 24 h under free-running conditions, (b) that is temperature compensated, and (c) which can entrain to light/dark signals. In addition, a mutation that lengthens the circadian period of the phototactic rhythm similarly affects the cell division rhythm. We conclude that a circadian mechanism determines the timing of cell division in Chlamydomonas reinhardtii.

Animals↗
PubMed1995

Effects of embryo density and co-culture of unfertilized oocytes on embryonic development of in-vitro fertilized mouse embryos.

We have evaluated the effects of embryo density and the co-culture of unfertilized (degenerating) oocytes on the development of in-vitro fertilized (IVF) mouse embryos. In experiment 1, groups of one, five, 10 or 20 zygotes were cultured in 20 microliter drops of modified human tubal fluid (HTF) medium for 168 h at 38.7 degrees C in 5% CO2 and 95% air. As the embryo density increased, significantly (P < 0.05) higher rates of embryos reached hatched blastocyst stage. In addition, the time required for hatching after IVF was significantly (P < 0.05) shortened by the increase in embryo density. In experiment 2, 10 IVF zygotes were cultured with or without 10 unfertilized (degenerating) oocytes in 20 microliter drops of HTF medium. The rates of IVF embryos that developed to morula, blastocyst, expanded blastocyst and hatched blastocyst stages were decreased significantly (P < 0.01) by culturing embryos with unfertilized oocytes compared with culturing embryos alone. In experiment 3, groups of one or 10 IVF zygotes or 10 IVF zygotes plus 10 unfertilized oocytes were cultured in 20 microliter drops of HTF medium and the number of cells per blastocyst was examined at 120 h after IVF. Increasing embryo density resulted in a significant (P < 0.05) increase in the number of cells per blastocyst. In contrast, the cell number of IVF embryos that developed to blastocyst decreased significantly (P < 0.05) when they were cultured with unfertilized oocytes. The results suggest that in-vitro development of IVF mouse embryos is enhanced by increasing embryo density and is impaired by co-culture with unfertilized (degenerating) oocytes.

Animals↗
PubMed1995

What is the difference of bone growth in SHR and SD rats?

1. Both sexes of spontaneously hypertensive rats (SHR) and Sprague-Dawley (SD) rats were used in this study. 2. At 6, 12, 18, 24, 30, 36, 42, 48, 54 and 60 weeks old, tibia length (L), volume (V), dry weight (DW), bone mineral density (BMD) in tibia and serum biochemical parameters (Ca2+, Ca, iP, ALP, TRAP) were measured. 3. At the 18 and 48 weeks old, bone morphometry was performed (mineral apposition rate, trabecular bone volume and trabecular thickness). Serum PTH and osteocalcin level were determined in 18 week old rats. 4. The time course change of DW, L and V were almost the same as the trends of bodyweight in each group, namely, male SD had the highest value, female SD and male SHR showed the same value and the lowest figures were obtained in female SHR. 5. BMD of the middle area showed almost the same trends with the time course change of bodyweight. On the other hand, both sexes of SHR had lower BMD than that of SD in the proximal area. 6. Serum biochemical parameters showed the same trends in both sexes of SD and SHR except for ALP (a marker of bone formation) which was higher in male than in female rats. 7. Mineral apposition rate, trabecular bone volume and trabecular thickness were not different between the same sex of SD and SHR. 8. These findings suggest that trabecular bone in SHR had a lower mineral status than that of SD rats not only in the adult but also in the young. This alteration may due to the abnormal mineralization mechanisms.

Aging↗
PubMed1995

Effects of pyridoxalated hemoglobin polyoxyethylene conjugate and other hemoglobin-related substances on arterial blood pressure in anesthetized and conscious rats.

The effects of pyridoxalated hemoglobin polyoxyethylene conjugate (PHP) and other hemoglobin-related substances on arterial blood pressure (ABP) and heart rate (HR) were examined. Infusion of PHP and other hemoglobin-related substances elevated ABP and increased HR. The degree of the increase in ABP and HR did not differ among the groups. There were species' differences in responses to PHP. Pretreatment with various blockers did not abolish the elevation of ABP. The pretreatment of NG-monomethyl-L-arginine dose-dependently reduced the elevation of ABP but did not completely abolish it. PHP also elevated ABP in conscious rats. The magnitude of the ABP elevation was significantly smaller than in the anesthetized rats. Results indicate that inhibition of nitric oxide (NO) might be responsible in part for the elevation of ABP, and the degree of the elevation would be dependent on the degree of contribution of NO to the regulation of ABP.

Adrenergic Antagonists↗
PubMed1995

HTLV-I associated uveitis in central Japan.

AIMS/BACKGROUND: Recently HTLV-I has been shown to cause a kind of endogenous uveitis in south west Japan, where HTLV-I infection is highly endemic. To investigate further the association of HTLV-I infection with the incidence of this uveitis, HTLV-I seroprevalence in central Japan, where HTLV-I infection is not endemic, was studied. METHODS: HTLV-I seroprevalence was investigated in 1579 patients with various ocular diseases and 1251 normal volunteers as a younger control group. Then HTLV-I seroprevalence was compared in each group. RESULTS: Of 1579 patients with various ocular diseases, 38 (2.41%) were seropositive. There was a statistically significant difference in HTLV-I seroprevalence between the undefined uveitis group and non-uveitic ocular diseases group (p < 0.05, Yates's correction). However, the seroprevalence in younger patients with undefined uveitis did not differ significantly from that in other groups. As regards the incidence of this type of uveitis, six of 12 (50%) seropositive patients, who were born in south west Japan and had lived in this area for 35 years, developed this undefined uveitis whereas only two of 26 (7.69%) seropositive patients in the other areas in Japan developed this uveitis. The difference was statistically significant (p < 0.05, Fisher's exact probability test). CONCLUSION: These results suggest that the incidence of this type of endogenous uveitis could be greatly influenced by environmental or hereditary factors including HLA.

Adolescent↗
PubMed1995

The effect of bosentan, a new potent endothelin receptor antagonist, on the pathogenesis of cerebral vasospasm.

Using the canine chronic cerebral vasospasm model, we studied the effects of a potent new nonpeptidic endothelin-1 (ET1) receptor antagonist, bosentan (Ro 47-0203, 4-tert-butyl-N-[6-(2-hydroxy-ethoxy)-5-(2-methoxy-phenoxy)-2,2'-bipyr imidin-4 - yl]-benzenesulfonamide). Endothelin (ET) receptors are composed of the ETA receptors and the ETB receptors; ET1 acts on both of these receptors. Although it has been previously thought that the ETA receptor mediates vasoconstriction, whereas the ETB receptor mediates vasodilation, recent evidence suggests that ETB receptor also contributes to vasoconstriction. Because bosentan is a mixed antagonist that acts on both receptors, its use might indicate whether or not ET is involved in the pathogenesis of cerebral vasospasm. In this study, beagle dogs received a double injection of autologous arterial blood into the cisterna magna at 2-day intervals (i.e., on Days 0 and 2). The diameter of the basilar artery (BA) was angiographically examined up to Day 7. A total of 24 dogs were randomly allocated to either the treatment group or the no-treatment group. Eight dogs were treated with 10 mg/kg bosentan by a one-dose injection into a central venous catheter. Bosentan was given twice a day starting immediately after the first subarachnoid hemorrhage for 6 days until Day 5. Sixteen dogs served as controls, with untreated subarachnoid hemorrhage. After the injection of bosetan, blood pressure decreased by about 25 mm Hg for a few minutes and then returned to normal. In the dogs treated with bosentan, the BA spasm on Day 7 was significantly ameliorated compared with the BA spasm in the untreated dogs.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Genotyping of mouse hepatitis virus strains by restriction endonuclease analysis of amplified nucleocapsid protein genes.

Restriction endonuclease analysis of amplified nucleocapsid protein genes from mouse hepatitis virus (MHV) was used to differentiate 12 strains isolated from mouse liver or transplantable tumors from five facilities, and the restriction patterns of the isolates were compared with those of five well-defined MHV strains, A59, JHM, 2, S and Nu-67. The patterns of 10 isolates from three facilities were the same as that of Nu-67. The remaining two isolates revealed different patterns from the five reference strains. This study showed that reverse transcription and the polymerase chain reaction assay based restriction analysis are feasible for the detection and genotyping of MHV, and the Nu-67 related strain was the most prevalent type found in the clinical samples.

Animals↗
PubMed1995

Detection of cilia-associated respiratory bacillus in experimentally and naturally infected mice and rats by the polymerase chain reaction.

Cilia-associated respiratory (CAR) bacillus was detected by means of the reverse transcription (RT)-polymerase chain reaction (PCR), and the results were compared with those of indirect immunofluorescence test (IFAT) for the detection of the organism. In the experimental infections, 15 mice were in contact with mice previously inoculated with CAR bacillus. Three mice each were tested at days 3, 5, 7, 12 and 20 postexposure. On day 3 postexposure, CAR bacillus was detected in oral swab samples from all 3 mice by RT-PCR, but was not detected in any sampling sites from the mice by IFAT. Total numbers of positive samples from nasal, oral and tracheal swabs obtained through the test were 6/15, 14/15 and 8/15, respectively, by RT-PCR, and 2/15, 6/15 and 3/15, respectively by IFAT. For the detection of CAR bacillus in samples from 52 rats, 34 serum antibody negative rats by enzyme-linked immunosorbent assay were also negative by RT-PCR and IFAT except for one sample from the oral cavity, and all serum antibody positive rats were positive for the organism by RT-PCR but it could not be detected in five of them by IFAT. By means of RT-PCR, no differences in the positive rates depending on sampling sites were observed except in one rat. The RT-PCR was found to be a specific, highly sensitive and reliable procedure for detecting CAR bacillus in mice and rats. The oral cavity was the most suitable site for the diagnosis of the early stage of this infection by RT-PCR.

Animals↗
PubMed1995

Divergent effects of gonadotrophin-releasing hormone (GnRH) analogue and authentic GnRH on the anterior pituitary gland of rats with restricted feeding.

The effects of gonadotrophin-releasing hormone analogue (GnRHa; buserelin) on the pituitary function and morphology of food-restricted rats were compared with those of authentic GnRH. After adult female rats had been restricted to 10 g food/day for 60 days, various doses of GnRHa (10 ng, 100 ng and 1 microgram) or GnRH (10 micrograms) were administered either daily for 7 days or twice a week for 4 weeks from day 61 of the period of underfeeding. Underfeeding brought about a decrease in the pituitary gonadotrophin content, serum levels of gonadotrophins and oestradiol, and the number and size of both LH- and FSH-positive pituitary cells. Daily and/or twice-weekly administration of authentic GnRH to underfed rats produced an increase in pituitary and serum gonadotrophin levels and the number and size of both LH- and FSH-positive pituitary cells. The administration of GnRHa daily for 7 days increased serum gonadotrophin levels, while it produced a reduction in the pituitary gonadotrophin content and number and size of both LH- and FSH-positive pituitary cells in a dose-dependent manner. Twice-weekly administration of GnRHa also produced an elevation of serum gonadotrophin levels and reduction of pituitary gonadotrophin content, although it did not affect the numbers and areas of LH- and FSH-positive pituitary cells. A GnRH loading test performed after the GnRHa treatment showed that the GnRHa treatment performed in this study did not produce down-regulation of the GnRH receptor. Thus, it can be concluded that the gonadotrophin-synthesizing activity of GnRHa is weaker than that of authentic GnRH, or that GnRHa may preferentially exert gonadotrophin-releasing activity rather than gonadotrophin-synthesizing activity in the anterior pituitary of underfed rats.

Animals↗
PubMed1995

Modulation of glomerular endothelin and endothelin receptor gene expression in aminonucleoside-induced nephrosis.

This study assessed glomerular endothelin (ET)-1, ET-3, and ET-receptor A and B mRNA levels in puromycin aminonucleoside (PAN)-induced nephrosis. During the nephrotic stage, 8 days after PAN injection, ET-1 and ETB receptor mRNA were elevated by 2.8 +/- 0.8-fold (P < 0.01) and 2.4 +/- 0.9-fold (P < 0.01), respectively, as compared with controls. These mRNA levels decreased to control levels by Day 20, when the nephrosis was in remission. In contrast, glomerular ETA receptor mRNA levels did not change in PAN nephrosis or control rats during the experimental period. ET-3 mRNA was not detected in the glomeruli of PAN nephrosis or control rats. Additionally, plasma ET concentration and glomerular ET production were measured in PAN nephrosis and control rats by radio-immunoassay. Eight days after PAN injection, ET-1 levels in plasma and glomeruli were not significantly altered in rats with PAN-induced nephrosis (glomeruli, 104.68 +/- 16.46 pg/mg of protein versus 98.24 +/- 13.68 pg/mg of protein; plasma, 2.68 +/- 1.10 versus 2.52 +/- 0.98 pg/mL). The administration of methylprednisolone to PAN rats resulted in the rapid disappearance of proteinuria and partially attenuated the increased ET-1 and ETB receptor gene expression in the glomeruli. These data indicate that glomerular ET-1 and ETB receptor expression in PAN nephrosis in increased at the mRNA level and that methylprednisolone treatment results in an attenuated increase.

Animals↗
PubMed1995

Effect of the potassium channel opener YM934 on the contractile response to electrical field stimulation in pig detrusor smooth muscle.

PURPOSE: The effect of a potassium channel opener, YM934, on the contractile response to excitatory neurotransmitters was investigated in isolated pig detrusor smooth muscle. MATERIALS AND METHODS: Electrical field stimulation (EFS; 5 second trains, 50 V, 0.8 msec. duration), alpha, beta-MeATP (3 x 10(-7) to 10(-5) M.) or carbachol (3 x 10(-8) to 10(-6) M.) produced a contractile response in isolated pig detrusor smooth muscle. The effect of YM934 on the contractile responses was evaluated in comparison with the antagonism of the putative cotransmitters, acetylcholine and ATP. RESULTS: A tetrodotoxin-sensitive, frequency-dependent contractile response to electrical field stimulation was obtained. Atropine (3 x 10(-8) M.) significantly inhibited the contractile response at high frequencies, whereas alpha, beta-MeATP (5 x 10(-6) M.) (desensitizer of P2X-purinoceptors) significantly inhibited the response at low frequencies. YM934 (10(-8) to 10(-7) M.) dose-dependently inhibited the nerve-mediated contractile responses to all frequencies but preferentially at low frequencies, by analogy with alpha, beta-MeATP. A combination of YM934 (3 x 10(-8) M.) and atropine (3 x 10(-8) M.) reduced the response at all frequencies to between 10 and 20% of control, an effect similar to that obtained with alpha, beta-MeATP (5 x 10(-6) M.) and atropine (3 x 10(-8) M.). In addition, YM934 (3 x 10(-8) M.) markedly inhibited the contractile response induced by exogenously applied alpha, beta-MeATP (3 x 10(-7) to 10(-5) M.) but only slightly inhibited the contractile response induced by exogenously applied carbachol (3 x 10(-8) to 10(-6) M.). CONCLUSION: These results suggest that YM934 may hyperpolarize the membrane of pig detrusor smooth muscle through the opening of ATP-sensitive potassium channels and, as a result, may functionally inhibit the contractile response to purinergic nerve stimulation that elicits the membrane depolarization.

Adenosine Triphosphate↗
PubMed1995

Spontaneous recurrence of methamphetamine psychosis: process and monoamine neurotransmitter function.

We studied the process that causes a spontaneous recurrence of methamphetamine (MAP) psychosis, a phenomenon known as flashbacks, in 41 female flashbackers by a comparison of clinical characteristics between the 41 flashbackers and 87 non-flashbackers with previous MAP psychosis. We evaluated plasma levels of monoamine metabolites in 25 of the 41 flashbackers, 19 of the 87 non-flashbackers, 9 female patients with persistent MAP psychosis and 61 physically healthy female controls. All 41 flashbackers had experienced a significantly greater frequency of threatening events and threatening paranoid-hallucinatory states than the 87 non-flashbackers during previous MAP abuse. The triggering factor was a mild fear of other persons due to the evocation of frightening images, encoded through threatening experiences during previous MAP abuse. Norepinephrine (NE) levels were significantly associated with a history of flashbacks. Plasma 3-methoxy-4-hydroxyphenylglycol (MHPG) levels were significantly higher during flashbacks and during periods of normalcy in the flashbackers, and in the non-flashbackers, than MHPG levels in the user controls. NE levels in the patients with persistent MAP psychosis were also significantly higher than NE levels in the user controls. Elevated NE levels in the flashbackers were associated with disrupted NE, 5-HT and DA turnover. Thus, MAP-induced sensitization to frightening images may have caused the flashbacks due to aggravated noradrenergic hyperactivity.

Adult↗
PubMed1995

[A characteristic blink response observed in a patient with Lance-Adams syndrome--somatosensory-evoked blink response].

We report a patient with Lance-Adams syndrome, in whom a characteristic blinking response was observed. In this patient, the reflex blinking was elicited by electrical stimulations applied not only to the supraorbital nerve but also to peripheral nerves of both upper and lower extremities. The EMG discharges responsible for the blinking response were found to consist of some components. The pathophysiological mechanism underlying the characteristic blinking response was discussed. It is speculated that increased excitabilities of the brainstem reticular formation may play a role in generating this type of blinking response, namely the somatosensory-evoked blink response.

Adult↗