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Biomedical subjects

M Shigeta

Publications and source records attributed to M Shigeta.

At least 37 records · Page 2Linked to original sources
PubMed2000

Bronchial hyperresponsiveness before and after the diagnosis of bronchial asthma in children.

OBJECTIVE: To assess at what age bronchial hyperresponsiveness (BHR) is acquired in children with asthma. BACKGROUND: A relationship between BHR and infantile wheezing diseases has been reported. Infants with a genetic predisposition to atopy are more likely to wheeze with respiratory viral infection or bronchiolitis, and it is suspected that the continued BHR after the first attack of asthma may be induced or triggered by some viral infections. Also, recent studies have reported the existence of atopic and BHR-related genes. However, whether BHR is congenital or acquired after asthma attacks, and when BHR in children with asthma is established or acquired remain unclear. METHODS: We performed methacholine inhalation challenge using a transcutaneous oxygen pressure (tcPO(2)) monitoring system in 205 children without asthma from 6 months to 6 years of age. During follow-up, 18 of these participants were diagnosed with asthma (group N-A). This group and 15 age-matched children without asthma (group N-N) were tested twice using methacholine inhalation challenge. For comparison, 39 age-matched atopic-type asthmatic children (group A-A) were also given the inhalation challenge twice. Methacholine inhalation challenge using a tcPO(2) monitoring system was performed while the participants were asleep in the supine position. Sequential doses of inhaled methacholine delivered by oxygen mask were doubled until a 10% decrease in tcPO(2) from the baseline was reached. The cumulative dose of methacholine at the inflection point of tcPO(2) (minimal dose of methacholine [Dmin]-PO(2)) was considered to represent BHR. RESULTS: In groups N-N and A-A, there was no difference in Dmin-PO(2) between the first and second challenge. However, the Dmin-PO(2) in group N-A significantly decreased from the first challenge to the second challenge. There was no significant difference between the Dmin-PO(2) in group N-N and the first Dmin-PO(2) in group N-A; or between the Dmin-PO(2) in group A-A and the second Dmin-PO(2) in group N-A. CONCLUSIONS: These data suggest that BHR in many infants with asthma is acquired after several asthma attacks.bronchial hyperresponsiveness, childhood asthma, methacholine inhalation challenge, transcutaneous oxygen pressure.

Asthma↗
PubMed1999

Characterization of a novel rat brain glycosylphosphatidylinositol-anchored protein (Kilon), a member of the IgLON cell adhesion molecule family.

In the central nervous system, many cell adhesion molecules are known to participate in the establishment and remodeling of the neural circuit. Some of the cell adhesion molecules are known to be anchored to the membrane by the glycosylphosphatidylinositol (GPI) inserted to their C termini, and many GPI-anchored proteins are known to be localized in a Triton-insoluble membrane fraction of low density or so-called "raft." In this study, we surveyed the GPI-anchored proteins in the Triton-insoluble low density fraction from 2-week-old rat brain by solubilization with phosphatidylinositol-specific phospholipase C. By Western blotting and partial peptide sequencing after the deglycosylation with peptide N-glycosidase F, the presence of Thy-1, F3/contactin, and T-cadherin was shown. In addition, one of the major proteins, having an apparent molecular mass of 36 kDa after the peptide N-glycosidase F digestion, was found to be a novel protein. The result of cDNA cloning showed that the protein is an immunoglobulin superfamily member with three C2 domains and has six putative glycosylation sites. Since this protein shows high sequence similarity to IgLON family members including LAMP, OBCAM, neurotrimin, CEPU-1, AvGP50, and GP55, we termed this protein Kilon (a kindred of IgLON). Kilon-specific monoclonal antibodies were produced, and Western blotting analysis showed that expression of Kilon is restricted to brain, and Kilon has an apparent molecular mass of 46 kDa in SDS-polyacrylamide gel electrophoresis in its expressed form. In brain, the expression of Kilon is already detected in E16 stage, and its level gradually increases during development. Kilon immunostaining was observed in the cerebral cortex and hippocampus, in which the strongly stained puncta were observed on dendrites and soma of pyramidal neurons.

Amidohydrolases↗
PubMed1999

Prune-belly syndrome diagnosed at 14 weeks' gestation with severe urethral obstruction but normal kidneys.

A fetus was diagnosed with prune-belly syndrome (PBS) found by ultrasound demonstration of cystomegaly at 12 weeks' gestation. Fetal urinary electrolyte and beta2-microglobulin concentrations at 14 weeks' gestation indicated a poor renal prognosis. The pregnancy was therefore terminated. An autopsy showed defects of the abdominal wall muscles and megalocystis caused by severe urethral obstruction. However, the kidneys were histologically normal. Together with previous reports, the present case suggests that renal dysplasia in PBS with severe uretheral obstruction may develop after 14 weeks' gestation. We discuss the possibility of preventing the development of renal dysplasia in PBS by early prenatal decompression of the obstructed fetal urinary tract.

Abortion, Induced↗
PubMed1999

Relationship between the sperm motility index assessed by the sperm quality analyzer and the outcome of intracytoplasmic sperm injection.

PURPOSE: Intracytoplasmic sperm injection (ICSI) has been validated as a useful treatment in severe male-factor patients who could not achieve fertilization and live births by conventional in vitro fertilization treatment. To examine the impact of male factors on ICSI outcome, clinical laboratory data were retrospectively analyzed. METHODS: One hundred two cycles of ICSI treatment indicated by severe male-factor infertility were entered into this study. Sperm parameters including sperm motility, sperm concentration, and sperm motility index assessed by the Sperm Quality Analyzer were evaluated. RESULTS: Five hundred seventy-six metaphase II oocytes retrieved were manipulated. The normal fertilization (2 PN) rate per oocyte was 64.9 +/- 26.0% (mean +/- SD). Of the 99 transfers, 31 clinical pregnancies were obtained, yielding an average pregnancy rate of 31.3% per transfer. The mean sperm motility, sperm concentration, and sperm motility index were 20.3 +/- 16.1% (range, 0 to 50%), 18.2 +/- 25.1 x 10(6)/ml (range, < 1 to 150 x 10(6)/ml), and 31.2 +/- 45.0 (range, 0 to 220), respectively. Sperm concentration did not have a significant impact on fertilization rate by ICSI. In four cases, ICSI was performed using totally immotile sperm and the fertilization rate was 43.5%, which was significantly lower than that of some of the other sperm motility groups, and no pregnancy could be achieved. In 14 cases in which the sperm motility index assessed by the Sperm Quality Analyzer was 0, the fertilization rate (50.0%) was significantly lower than in most of the other sperm motility index groups. CONCLUSIONS: These findings suggest that in severe male-factor cases with totally immotile sperm or a sperm motility index of 0, the selection of good-quality sperm should be verified before injection.

Female↗
PubMed1999

Correlation between the motility of frozen-thawed epididymal spermatozoa and the outcome of intracytoplasmic sperm injection.

The purpose of this study was to investigate if the outcome of ICSI was influenced by epididymal sperm motility in frozen-thawed specimens. A total of 18 ICSI treatment cycles using spermatozoa retrieved by microsurgical epididymal sperm aspiration (MESA) were analysed retrospectively. Cryopreservation of epididymal spermatozoa was performed when enough epididymal aspirates were collected. Sixty-nine out of 126 oocytes injected with spermatozoa retrieved by MESA were fertilized, giving a fertilization rate of 54.8%. Out of 18 embryo transfer cycles, 6 (33.3%) achieved pregnancies. Fresh epididymal spermatozoa were used in 5 cycles while frozen-thawed epididymal spermatozoa were used in 13 cycles for ICSI. The fertilization rates were 68.6% (35/51) in the former group and 45.3% (34/75) in the latter group, respectively. There was a significant difference between the two groups (p < 0.05). In ICSI treatments using fresh epididymal spermatozoa, the cells used for injection were all motile. However, motile epididymal spermatozoa could be used in only five ICSI treatment cycles after freeze-thawing. In 6 cycles, only immotile sperm were used for injection of frozen-thawed spermatozoa. The fertilization rate in each group was 68.4% (13/19) and 31.6% (12/38), respectively. There was a significant difference between these groups (p < 0.01). These results indicate that the outcome of ICSI was influenced by sperm motility in frozen-thawed epididymal specimens. When no sperm motility could be recovered after freeze-thawing even with chemical treatments, consideration should be given to retrieving fresh epididymal spermatozoa again to achieve a better fertilization rate in such patients.

Epididymis↗
PubMed1999

Fate of residual fragments after successful extracorporeal shock wave lithotripsy.

PURPOSE: The aim of the present study was to investigate the reason residual fragments from upper urinary tract calculi failed to clear after successful extracorporeal shock wave lithotripsy (ESWL). METHODS: Risk factors were analyzed in 161 patients with residual fragments (< or = 4 mm) that had remained for more than 3 months after ESWL. The factors examined in the present study were gender, a history of urolithiasis, the number, location and size of stones, hydronephrosis 3 months after ESWL and bacteriuria before ESWL. The mean follow-up period was 20.0 months (range 6-69 months). RESULTS: The overall stone-free rate was 14.3%. The stone-free rate in patients with multiple stones or hydronephrosis 3 months after ESWL was significantly lower than that in patients without these conditions (P < 0.05 and P < 0.01, respectively). The cumulative non-clearance rate in patients with hydronephrosis was significantly higher than in patients without this condition (P < 0.05). Results of Cox's proportional hazards model indicated that hydronephrosis was the most important and only significant factor for failure to clear of the seven factors investigated (P < 0.05). CONCLUSION: Hydronephrosis was most highly correlated with the fate of residual fragments after ESWL.

Adolescent↗
PubMed1999

Prenatal sonographic diagnosis of a fetal renal mesoblastic nephroma occurring after transfer of a cryopreserved embryo.

Here we report the first case of prenatally diagnosed fetal renal mesoblastic nephroma occurring after transfer of a cryopreserved embryo. A 37 year old woman, having immunological infertility, was treated by in-vitro fertilization (IVF) and embryo transfer. Following unsuccessful IVF using fresh embryos, the patient conceived after transfer of cryopreserved-thawed embryos. The chromosomal analysis identified a normal karyotype at 16 weeks' gestation when amniocentesis was performed. The pregnancy course was uneventful until 28 weeks' gestation when polyhydramnios associated with fetal renal tumour was detected using ultrasonography. A male infant weighing 2564 g was born via Caesarean section at 34 weeks' gestation. A left nephrectomy was performed 5 days after delivery and the tumour was identified histologically as a mesoblastic nephroma. The postoperative course was uncomplicated to this point.

Adult↗
PubMed1999

Successful pregnancy in an infertile patient with conservatively treated endometrial adenocarcinoma after transfer of embryos obtained by intracytoplasmic sperm injection.

A rare case of successful pregnancy in a woman with early-stage endometrial adenocarcinoma conservatively treated is presented. The patient, having polycystic ovaries, was initially diagnosed with hyperplasia of the endometrium and treated with several cycles of ovulation induction following intrauterine insemination. Then dilatation and curettage were carried out when hysteroscopy was performed. The histology report identified a well-differentiated adenocarcinoma of the endometrium. After repeated endometrial curettage, in-vitro fertilization and embryo transfer were introduced for immediate treatment of the patient's infertility in order to avoid the risk of recurrence of neoplastic endometrial lesions by oestrogens. A single pregnancy was achieved after transfer of the embryos obtained after intracytoplasmic sperm injection. This was performed due to the poor semen characteristics (asthenozoospermia). The patient delivered a healthy normal male infant at term. A transvaginal ultrasound examination 2 months after delivery showed a smooth, linear endometrium. Moreover, the histology report after endometrial biopsy was free of any malignancies. The patient now desires another pregnancy. We conclude that conservative treatment of early-stage endometrial adenocarcinoma in young women wishing to preserve fertility should be considered in carefully selected cases. Assisted reproductive technologies may be helpful for immediate achievement of pregnancy in such patients.

Adenocarcinoma↗
PubMed1999

Difference in airway reactivity in children with atopic vs nonatopic asthma.

STUDY OBJECTIVE: To examine the difference in the mechanisms of bronchial hyperresponsiveness (BHR) in nonatopic asthma and in atopic asthma, we studied bronchial reactivity against nonspecific stimuli in children with atopic asthma and nonatopic asthma. DESIGN AND PARTICIPANTS: Fourteen children with nonatopic asthma, 24 children with atopic asthma, and 20 age-matched controls participated in this study. MEASUREMENTS: Inhalation challenge was performed by administering progressively doubling doses of methacholine with a continuous inhalation provocation method. The speed of bronchoconstriction to methacholine (Sm) and the speed of reversal of bronchoconstriction to methacholine after inhalation of a beta2-agonist (r-Sm), which was considered to represent the effect of the beta2-agonist, were calculated from the dose-response curve. RESULTS: The value of Sm was higher in the nonatopic asthma group than in the atopic asthma group and the control group. The value of r-Sm was also higher in the nonatopic asthma group than in the atopic asthma group, but did not differ from that in the control group. CONCLUSION: These results indicate that bronchial reactivity against methacholine and the beta2-agonist was greater in nonatopic asthma than in atopic asthma, and that the mechanism of BHR in children with nonatopic asthma may differ from that in children with atopic asthma.

Adolescent↗
PubMed1998

EEG slowing and cerebrospinal fluid tau levels in patients with cognitive decline.

We explored the relationship between cerebrospinal fluid (CSF) tau levels as indirect markers of tau-related pathology in Alzheimer's disease (AD) and EEG slowing, a typical neurophysiological finding in the disease. A positive correlation between CSF tau levels and ratio of alpha/delta global field power was found in 14 AD patients (r = 0.65, p = 0.01). This relationship was better approximated by polynomial fit of 2nd degree (p = 0.002). A subgroup of AD patients (n = 7) with higher tau levels and shorter duration of illness showed a strong relationship between CSF tau levels and alpha/theta (r = 0.83, p = 0.02), and alpha/delta (r = 0.87, p = 0.01) ratios of the global field power. There were no significant correlations between EEG slowing and CSF tau levels in 12 patients with mild cognitive dysfunction or in 14 healthy control subjects. That a strong inverse linear correlation exists in AD patients with higher levels of tau and shorter duration of illness may imply that with longer illness duration CSF tau levels decrease due to neuronal death.

Aged↗
PubMed1998

Lysinuric protein intolerance and systemic lupus erythematosus.

UNLABELLED: We report lysinuric protein intolerance (LPI) and systemic lupus erythematosus (SLE) in a 14-year-old girl. The co-existence of LPI and SLE in the same patient has been reported before and suggests that SLE is directly connected with LPI. CONCLUSION: Possibly in LPI the metabolic derangement can cause immunological abnormalities. Therefore, when multisystem involvement is observed in LPI patients, SLE should be considered as a rare complication.

Adolescent↗
PubMed1998

Quantitative electro-oculography and electroencephalography as indices of alertness.

Even though both electro-oculography (EOG) and EEG have been widely used for assessing alertness, the relationship between these two measures has not yet been clarified at various alertness levels. We estimated the frequencies of eye movements faster than 15 degrees/s (NoEM15) and EEG power at every 0.5 Hz step frequency point, quantitatively as well as continuously from alert to very light sleep (Stage 1) in 14 healthy adults. We devised a new EOG derivation for a computerized analysis, because conventional EOG recordings suffer from EEG contamination and have been analyzed manually. EOG electrodes were attached to the left orbitale in this study. The eye movements were detected as peaks in differentiated EOG signals. Significant correlations were found between NoEM15 and EEG powers at several frequency points, mainly in the alpha and beta bands. Though fluctuating EEG components in close correspondence to the frequency of the eye movements varied depending on the individual, EEG power at the peak frequency of the awake state was most closely associated with the eye movements. A broad band power that centers at the peak frequency may be a better measure for alertness assessment than powers in fixed bands.

Adolescent↗
PubMed1998

Relationship between human in-vitro fertilization and intracytoplasmic sperm injection and the zona-free hamster egg penetration test.

The zona-free hamster egg penetration test (HEPT) is widely used for evaluating the fertilizing ability of human spermatozoa. However, the relationship between the HEPT and microassisted fertilization has yet to be determined. To evaluate the efficiency of HEPT in selecting the most appropriate method of in-vitro fertilization (IVF), including intracytoplasmic sperm injection (ICSI) in couples with male factor infertility, clinical laboratory data was analysed retrospectively. The patients were divided into groups according to the sperm penetration index as determined by the HEPT: group A (sperm penetration index = 0), group B (sperm penetration index < 15) and group C (sperm penetration index > or = 15). A total of 405 oocytes were collected and inseminated by conventional methods in 69 couples with male factor infertility. In all, 31 out of 148 (20.9%) oocytes fertilized in group A; 35 out of 117 (29.9%) in group B; and 73 of 140 (52.1%) in group C. The clinical pregnancy rates per transfer in groups A, B and C were 0% (0/13), 0% (0/14) and 25.9% (7/27) respectively. Both the fertilization rate and pregnancy rate in group C was significantly higher than in groups A and B. ICSI was carried out in a total of 57 couples and 334 oocytes in metaphase II stage were manipulated. The normal fertilization (2 pronuclear) rate per oocyte was 65.6 +/- 26.0% (mean +/- SD). Out of 127 oocytes, 76 (59.8%) fertilized in group A, 57 out of 87 oocytes (65.5%) in group B and 86 out of 120 oocytes (71.7%) in group C. Of the 56 transfers, 17 clinical pregnancies were obtained, giving an average pregnancy rate of 30.4% per transfer. The clinical pregnancy rates per transfer in groups A, B and C were 17.4% (4/23), 40.0% (4/10) and 39.1% (9/23) respectively. No significant differences were observed in the fertilization rates or in the pregnancy rates between the three groups. In addition, there were no differences in the fertilization and pregnancy rates between the ICSI and IVF patients in group C. These findings suggest that the results of the HEPT are well correlated with the fertilizing ability of human spermatozoa in the patients treated by conventional IVF. Couples suffering from male factor infertility with a sperm penetration index of < 15 (as determined by HEPT) should consider treatment with ICSI, while those with a sperm penetration index of > or = 15 should attempt conventional IVF.

Animals↗
PubMed1998

Long-term tacrine treatment in three mild Alzheimer patients: effects on nicotinic receptors, cerebral blood flow, glucose metabolism, EEG, and cognitive abilities.

The effect of long-term treatment with tacrine (tetrahydroaminoacridine) was studied in three Alzheimer patients (aged 57, 64, and 68 years) with mild dementia. All three patients had a Mini-Mental State Examination score of 24/30 and carried at least one apolipoprotein E (ApoE) epsilon4 allele. Tacrine was given in doses between 80 and to 160 mg daily for 13-31 months. A lower tacrine concentration was observed generally in cerebrospinal fluid (CSF) compared with plasma. The acetylcholinesterase activity in CSF tended to be increased following longer periods of tacrine treatment, whereas the butyrylcholinesterase activity was decreased. The three patients repeatedly underwent positron emission tomography investigation of cerebral blood flow, nicotinic receptors, cerebral glucose metabolism, and electroencephalogram (EEG) and cognitive tests. Positive influences on these parameters were observed following both short-term and long-term treatment with tacrine. Improvement of nicotinic receptors (measured as 11C-nicotine binding), cerebral blood flow, EEG, and some cognitive tests (trail making test, block design test) occurred earlier after initiation of tacrine treatment compared with the glucose metabolism, which was increased after several months of tacrine treatment. An improvement in attention (trail making test) was observed following tacrine as sign for frontal lobe activation (EEG). The functional effects of tacrine in Alzheimer patients appeared to be related to both dose and length of cholinesterase inhibitor treatment.

Aged↗
PubMed1998

Diurnal variation of peak expiratory flow in children with cough variant asthma.

Cough variant asthma (CVA) is thought to be a variant form of asthma in which cough is the sole clinical manifestation of airways hyperresponsiveness, a characteristic feature of asthma. Another characteristic feature of asthma includes an increased diurnal variation of peak expiratory flow (PEF) compared to normal subjects. To examine whether diurnal variation of PEF might also increase in children with CVA, we have examined the degree of diurnal variation of PEF in these children (n = 7) by measuring peak flow serially for a week, and compared it with those in mild to moderate asthma (n = 17) and in control children without cough (n = 8). In control children without cough, the average value of the mean diurnal variation of PEF was 10.4 +/- 0.8%. In both groups of children with asthma and with CVA, there was a significant increase in the value (20.5 +/- 1.3% and 23.6 +/- 3.6%, respectively) compared to that in control children (p < 0.01 in both groups), although there was no significant difference between these 2 groups. These results show that mild, but significant airway obstruction is occurring in children with CVA, although clinical wheezing is not recognized. Serial measurements of diurnal variation of PEF may be helpful for the diagnosis of CVA in children.

Asthma↗
PubMed1997

Evaluation of sperm fertilizing ability using the Sperm Quality Analyzer.

The Sperm Quality Analyzer is an inexpensive device which provides a quantitative estimation of sperm motility. To evaluate the fertilizing ability of human spermatozoa using a Sperm Quality Analyzer, correlations amongst the sperm motility index, the sperm penetration index (as assessed using the sperm penetration assay; SPA), and the fertilization rate in the treatment of standard IVF-ET were analysed retrospectively. The sperm motility index demonstrated a significant correlation with sperm concentration (p < 0.001), sperm motility (p < 0.001) and the motile sperm concentration (p < 0.001) in a total of 104 fresh semen samples from 81 men donating samples for IVF-ET. The sperm motility index also showed a significant correlation (p < 0.001) with the sperm penetration index in 60 patients, assessed using the SPA, before they were treated by standard IVF-ET. The correlation between the sperm motility index and the IVF-ET fertilization rate was higher than that between the sperm penetration index and the fertilization rate. The sperm motility index was classified into three categories: 'poor' (sperm motility index < 80), 'medium' (sperm motility index 81-160) and 'good' (sperm motility index > 160). The relationships between the IVF-ET fertilization rate and each category of the sperm motility index values were also evaluated. For the three categories in the sperm motility index, the fertilization rates (76.0%) of 60 samples judged as 'good' were significantly higher than those (44.2%) of 15 samples judged as 'medium' (p < 0.001) and those (34.7%) of 13 samples judged as 'poor' (p < 0.001). These results indicate that the Sperm Quality Analyzer provides a reliable estimation of the fertilizing ability of human spermatozoa.

Embryo Transfer↗