Biomedical subjects

K Sengoku

Publications and source records attributed to K Sengoku.

At least 19 recordsLinked to original sources

PubMed1999

Requirement of sperm-oocyte plasma membrane fusion for establishment of the plasma membrane block to polyspermy in human pronuclear oocytes.

We investigated whether the incorporation of the sperm membrane into the oolemma contributes to the human plasma membrane block to polyspermy. We used zona pellucida-free oocytes fertilized by intracytoplasmic sperm injection (ICSI) or activated by parthenogenetic activation. Only two of the 35 pronuclear oocytes fertilized by spermatozoa (control) demonstrated one single penetrating spermatozoa. In contrast, the majority of ICSI and parthenogenetically activated pronuclear oocytes were penetrated with an average of three spermatozoa per oocyte. The number of fused and binding spermatozoa of ICSI and parthenogenetically activated oocytes were significantly higher than in control oocytes (3.5+/-0.6 and 4.3+/-0.6 for ICSI; 3.0+/-0.3 and 3.8+/-0.4 for activated and 0.2+/-0.1 and 0.6+/-0.2 for controls, respectively, P < 0.01). Furthermore, the cortical granules were released from the cortex of ICSI and calcium ionophore-puromycin-activated pronuclear oocytes to the same extent as that of pronuclear oocytes fertilized by spermatozoa. These results suggest that the establishment of the plasma membrane block to sperm penetration in the human oocyte may require a fusion process between sperm and oocyte plasma membranes.

Cell Membrane↗

PubMed1999

The clinical efficacy of low-dose step-up follicle stimulating hormone administration for treatment of unexplained infertility.

The present study was designed to compare the clinical efficacy of low-dose step-up follicle stimulating hormone (FSH) administration with conventional FSH protocol (FSH was injected daily starting with a dose of 150 IU), both combined with intrauterine insemination (IUI), for the treatment of unexplained infertility. A total of 97 unexplained infertility couples was randomly assigned to one or other of the two treatment groups, either conventional FSH with IUI (48 patients) or low-dose step-up FSH with IUI (49 patients), and only the first treatment cycle was evaluated in each protocol. The difference in pregnancy rates per cycle was not statistically significant between the low-dose FSH group and the conventional group [seven of 49 (14.3%) and seven of 48 (14.6%) respectively]. A significant reduction in the incidence of ovarian hyperstimulation syndrome (OHSS) was observed in the low-dose group (8.3% versus 27.1%, P < 0.05). The incidence of moderate OHSS requiring hospitalization was reduced significantly in the low-dose group (low-dose 0% versus conventional 16.7%, P < 0.01). However, the low-dose protocol did not completely prevent multiple pregnancies. Our results suggest that the low-dose step-up FSH treatment appeared to be useful for the treatment of unexplained infertility because of the high pregnancy rates and the significant decrease in the incidence of OHSS.

Adult↗

PubMed1998

A SacII polymorphism in the human ASCL2 (HASH2) gene region.

The mouse achaete-scute homolog-2 gene (Ascl2 or Mash2) encodes a transcription factor playing a role in the development of the trophoblast. The Ascl2 gene is paternally imprinted in the mouse, but whether this applies to its human homolog is unknown. In the present study, we found a SacII polymorphism in the possible 3' untranslated region (UTR) of the gene. It would be very useful to determine definitively whether the gene is imprinted, as well as to analyze the allelic methylation status of the gene.

Alleles↗

PubMed1998

Effects of low concentrations of nitric oxide on the zona pellucida binding ability of human spermatozoa.

OBJECTIVE: To investigate the direct effects of sodium nitroprusside, a nitric oxide donor, on the fertilizing ability of human spermatozoa in vitro. DESIGN: Prospective, controlled in vitro study. SETTING: IVF Unit, Medical College Hospital. PATIENT(S): Women undergoing conventional IVF. INTERVENTION(S): Human spermatozoa samples were incubated with a nitric oxide donor and a nitric oxide quencher, carboxy-imidazolineoxyl N-oxides. MAIN OUTCOME MEASURE(S): The capacitation and the acrosome reaction rates were determined by chlortetracycline assay. Sperm zona pellucida binding and sperm penetration into oocytes were determined using the hemizona assay and the human aged zona-free oocyte sperm penetration assay. RESULT(S): High concentrations of sodium nitroprusside (10(-3) and 10(-5) M) inhibited sperm motility and viability. In contrast, low concentrations of sodium nitroprusside (10(-7) and 10(-8) M) did not affect motility and resulted in increased capacitation (47 +/- 6% at 10(-7) M, 42 +/- 6% at 10(-8) M, and 24 +/- 4% in controls, respectively, P < 0.01). A twofold increase in the hemizona index occurred compared to the matched control. However, low levels of sodium nitroprusside treatment did not affect the acrosome reaction and human zona-free oocyte sperm penetration rates. CONCLUSION(S): Low concentrations of nitric oxide may have some physiologic role in fertilization through the enhancement of capacitation and zona pellucida binding but not by the induction of the acrosome reaction or the facilitation of penetration into oocytes.

Acrosome↗

PubMed1997

Analysis of the Rb gene and cyclin-dependent kinase 4 inhibitor genes (p16INK4 and p15INK4B) in human ovarian carcinoma cell lines.

In the present study, we analyzed human ovarian carcinoma cell lines for abnormalities in the tumor suppressor gene Rb (retinoblastoma) and in cyclin-dependent kinase 4 (CDK4) inhibitor genes (p16INK4 and p15INK4B) using molecular biology techniques. For the Rb gene, in all six cell lines (PA-1, Caov-3 and -4, OVCAR-3, SK-OV-3, and Kuramochi), Rb gene abnormality was not detected using Southern blotting. In the Caov-3 cell line transcripts were not detectable by either Northern blot or polymerase chain reaction. Sequence analysis of the entire coding region of the Rb gene revealed point mutations (AAC to GAC) resulting in codon 123 (Asn to Asp) changes in the Caov-4 cell line. In the PA-1 cell line both wild-type Rb and mutant-type Rb (codon 798: CGG to TGG) were expressed, and in the OVCAR-3 cell line both wild-type Rb and mutant-type Rb (codon 704: ATG to GTG) were expressed. In four of six human ovarian carcinoma cell lines Rb gene abnormality was detected. For the p16INK4 and p15INK4B genes, only the SK-OV-3 cell line had abnormalities. There was a gene rearrangement or minor deletion of the p16INK4 gene in the SK-OV-3 cell line, while the p15INK4B gene was deleted in this cell line. In the SK-OV-3 cell line no mRNAs of p16INK4 and p15INK4B were expressed. At the point of Rb gene inactivation, we can explain five cell lines of six: four cell lines had abnormalities in the Rb gene itself, which is another mechanism by which the Rb gene is inactivated, while one cell line (SK-OV-3) had abnormalities in CDK4 inhibitor genes, another of the inactivation mechanisms of the Rb gene. These data suggest that abnormalities of Rb and CDK4 inhibitor genes (p16INK4, p15INK4B) may be involved in human ovarian carcinogenesis.

Carcinoma↗

PubMed1997

The chromosomal normality of unfertilized oocytes from patients with polycystic ovarian syndrome.

The present study was designed to compare the cycle characteristics of in-vitro fertilization (IVF) and the chromosomal normality of oocytes in patients with polycystic ovarian syndrome (PCOS) with those of patients with tubal factor infertility. In all, 28 cycles of 24 PCOS patients and 55 cycles of 31 patients with tubal factor infertility (control) were investigated. Although a significantly greater number of oocytes were retrieved from PCOS patients (mean +/- SD: 15.6 +/- 6.4 versus 9.0 +/- 4.0, PCOS versus control group, P < 0.05), the percentage of fertilized oocytes was significantly lower in the PCOS group compared with controls (40.1 versus 73.8%, P < 0.01). The pregnancy rate per embryo transfer did not differ between the two groups. Cytogenetic analysis was performed on 74 oocytes from PCOS patients and 73 oocytes from control patients. In the PCOS group, 10 of the 74 oocytes (13.5%) demonstrated aneuploidy, four (5.4%) oocytes were diploid and six (8.1%) oocytes were metaphase II with a prematurely condensed sperm chromosome (PCC). In the tubal infertility group, nine of the 73 (12.3%) oocytes showed aneuploidy, four (5.5%) oocytes were diploid and five (6.8%) oocytes were found to have PCC. There was no significant difference in the aneuploidy, diploidy and PCC rates between the two groups. These results suggest that the reduced fertilization observed in PCOS is not attributable to chromosomal aberrations or immaturity of oocytes recruited from patients with PCOS.

Adult↗

PubMed1996

Mouse/human sequence divergence in a region with a paternal-specific methylation imprint at the human H19 locus.

We have identified a region with characteristics of a paternal-specific methylation imprint at the human H19 locus. This region, extending from -2.0 kb upstream to the start of transcription, is heavily methylated in sperm and on the paternal allele in somatic cells. This methylation was preserved during pre-implantation. Structural analysis revealed the presence of CpG islands and a large direct repeat with a 400 bp sequence reiterated several times, but no significant sequence homology to the corresponding region of the mouse H19 gene. These findings could suggest a role for secondary DNA structure in genomic imprinting across the species, and they also present a puzzling aspect of the evolution of the H19 regulatory region in human and mouse.

Alleles↗

PubMed1996

Involvement of protein kinases in platelet activating factor-induced acrosome reaction of human spermatozoa.

The involvement of protein kinases in platelet activating factor (PAF)-induced acrosome reaction of human spermatozoa was investigated using specific inhibitors of protein kinase A (PKA), protein kinase C (PKC) and protein tyrosine kinase (PTK). PAF (10(-9)-10(-11) M) treatment of spermatozoa enhanced the acrosome reaction in a dose-dependent manner (32 +/- 4% at 10(-9) M, 28 +/- 4% at 10(-10) M and 24 +/- 3% at 10(-11) M respectively). When spermatozoa were preincubated with PKA, PKC and PTK inhibitor (KT5720, calphostin C and genistein) for 15 min prior to addition of PAF, there was a significantly reduced acrosome reaction induced by PAF, but complete inhibition was not observed. On the other hand, combined use of three inhibitors completely inhibited PAF-induced acrosome reaction to levels of non-treated samples. These results suggest that the induction of the acrosome reaction by PAF treatment may involve the activation of PKA, PKC and PTK signalling pathways, and that interaction between these pathways may regulate complex mechanisms of PAF-induced acrosome reaction.

Acrosome↗

PubMed1995

The role of superoxide dismutase in the human ovary and fallopian tube.

OBJECTIVES: To investigate the localization of manganese superoxide dismutase (Mn-SOD) and copper-zinc superoxide dismutase (Cu, Zn-SOD) in the human ovary and fallopian tube, and to examine the role of superoxide radicals and SODs in the human ovulatory process. METHODS: Using immunohistochemical methods, we studied the localization of SODs in 22 human ovaries, in 18 fallopian tubes, and in aspirated granulosa cells. We measured, by enzyme-linked immunosorbent assay, the concentrations of SODs in follicular fluid taken from 94 IVF patients. RESULTS: Mn-SOD was found in granulosa, in theca and luteal cells and in fallopian tubes. Cu, Zn-SOD was localized in theca and luteal cells. The concentration of Cu, Zn-SOD in follicular fluid in the high-progesterone group (11.3 + 4.2 ng/ml) was significantly less than in the low-progesterone group (24.5 + 19.5) (p < 0.05). CONCLUSION: Mn-SOD and Cu, Zn-SOD have different localizations and actions in human ovaries and fallopian tubes. The superoxide radical-SOD system might play an important role in ovulation and in the luteal function of the human ovary.

Body Fluids↗

PubMed1995

Plasma membrane block to polyspermy in human oocytes and preimplantation embryos.

The existence and time course of the human plasma membrane block to polyspermy were investigated by an in vitro fertilization assay using zona pellucida-free unfertilized oocytes, pronuclear oocytes and embryos. In the time course study using a high sperm concentration (10(5) spermatozoa ml-1), the number of penetrating spermatozoa at 30 and 60 min after insemination were 1.3 +/- 0.3 and 2.9 +/- 0.4, respectively. By 2 h after insemination, spermatozoa penetration reached a maximum. A lower maximum number of penetrating spermatozoa was observed at a low sperm concentration (10(4) spermatozoa ml-1), but the number of penetrating spermatozoa still reached a maximum by 2 h after insemination. A reinsemination experiment demonstrated that the number of penetrating spermatozoa was not significantly different between control and reinseminated oocytes, while sperm penetration was not observed in the oocyte beyond the two-cell stage. Furthermore, the number of binding spermatozoa decreased after fertilization and most of the four-cell stage embryos displayed no sperm binding. These results suggest that the plasma membrane block plays an important role in the prevention of polyspermy in the human oocyte, and that the plasma membrane block may involve permanent changes in the binding or fusion ability of spermatozoa in the oolemma after fertilization.

Blastocyst↗

PubMed1995

The use of zona-free aged unfertilized human oocytes as a predictor for successful subzonal insemination.

OBJECTIVE: To examine the reliability of the zona-free aged (1 day old) human unfertilized oocyte sperm penetration assay for assessing sperm fertilizing ability and to determine the predictive value of this assay for subsequent subzonal insemination (SUZI) outcomes. DESIGN: A total of 253 unfertilized oocytes from total fertilization failure patients and from good fertilization rate (> 70%) patients in standard IVF were inseminated with donors' spermatozoa, and penetration rates were compared in each group. Two hundred seventy-two unfertilized oocytes from total fertilization failure, poor fertilization (< 30%), and normal fertilization (> 30%) were inseminated with husbands' spermatozoa, and penetration rates were compared between the three groups. In 29 patients, the results of the zona-free assay performed in previous IVF were compared with the fertilization rates of subsequent SUZI. RESULTS: In the zona-free assay using donors' spermatozoa, there was no difference in penetration rates between the two groups (109/122, 89.3% versus 114/131, 87.0%). Penetration rates using partners' spermatozoa were positively correlated with fertilization rates in standard IVF (total fertilization failure 34/75, 45.3%; poor fertilization 56/77, 72.7%; normal fertilization 108/120, 90.0%). There was a significant difference in fertilization rates after SUZI between the patients with negative and positive penetration in zona-free assay (4/53, 7.5%, versus 54/174, 31.0%). CONCLUSION: The zona-free human oocyte assay may primarily reflect sperm fertilizing ability. This asssay also could be a reliable predictor for subsequent SUZI outcome.

Cellular Senescence↗

PubMed1995

[Four cases of noncardiac surgery after PTCA].

Malignant tumors were detected in four patients who had been hospitalized for acute myocardial infarction and/or postinfarction angina. All of them underwent curative operations after successful percutaneous transluminal coronary angioplasty (PTCA). Operations performed were partial colectomy on the first patient, low anterior rectal resection on the second patient, left pulmonary upper lobectomy on the third patient and partial colectomy with cholecystectomy on the fourth patient. There were no complications in the perioperative periods except the first patient in which postoperative electrocardiogram showed transient peaked T wave in leads II, III, AVf, V5 and V6. Forty six days after colectomy (55 days after PTCA), the first patient underwent emergency PTCA for restenosis. Prior PTCA, as well as CABG, is considered to have decreased cardiac complications in patients with ischemic heart disease. But when a non-cardiac operation should be done after PTCA, we should take restenosis into consideration.

Aged↗

PubMed1994

Evaluation of transvaginal color Doppler sonography, transvaginal sonography and CA 125 for prediction of ovarian malignancy.

OBJECTIVES: To evaluate the efficacy of color Doppler ultrasonography as the predictor of malignant ovarian tumors and to compare the results with CA 125 levels and ultrasonographic morphological patterns. METHODS: We compared color Doppler ultrasound with sonographic findings and serum CA 125 levels for predicting ovarian malignancy in 16 patients with malignant and 12 patients with benign ovarian tumors. RESULTS: There was a significant difference in pulsatility index (PI) value of ovarian vessel between benign and malignant tumors (2.42 +/- 0.67 for benign and 1.35 +/- 0.78 for malignant, respectively, P < 0.01). The specificity of morphological findings and CA 125 was lower than that of PI measurements, but sensitivity was not different between the three methods. In addition, the combination of color Doppler and CA 125 or morphological assessments resulted in a sensitivity of 100% and a negative predictive value of 100%, respectively. CONCLUSION: PI measurements by transvaginal color Doppler ultrasound combined with CA 125 levels or morphological findings could be an accurate and appropriate screening method for ovarian tumors.

Adult↗

PubMed1994

A randomized prospective study of gonadotrophin with or without gonadotrophin-releasing hormone agonist for treatment of unexplained infertility.

The use of gonadotrophin-releasing hormone agonist (GnRHa) in combination with human menopausal gonadotrophin (HMG) for ovulation induction has been advocated for the treatment, particularly by in-vitro fertilization (IVF) of various types of infertility. The present study was designed to compare the clinical efficacy of HMG alone with a short protocol of GnRHa/HMG for treatment of unexplained infertility. A total of 91 couples with unexplained infertility were randomly assigned to one of two treatments; either HMG with intra-uterine insemination (IUI) (45 patients, 62 cycles) or GnRHa/HMG with IUI (46 patients, 69 cycles) treatments. Progesterone concentrations on the day of human chorionic gonadotrophin (HCG) administration were significantly higher in HMG (1.5 +/- 0.9 ng/ml) versus GnRHa/HMG (0.8 +/- 0.6 ng/ml; P < 0.05) cycles. Furthermore, GnRHa suppressed the occurrences of premature luteinization (GnRHa/HMG 5.8% and HMG 24.2% respectively). However, there were no significant differences in HMG dose requirements, plasma oestradiol concentrations or follicular development on the day of HCG administration between the two groups. Nor were any significant differences found in the pregnancy rates between the two treatment protocols (GnRHa/HMG 13.0% and HMG 11.3% respectively). Our results suggest no beneficial effect of GnRHa/HMG compared to HMG alone for the treatment of unexplained infertility, based on pregnancy rates.

Adult↗

PubMed1994

[Basic and clinical studies on biapenem (L-627) in obstetrics and gynecology].

UNLABELLED: We investigated biapenem (BIPM, L-627) a newly carbapenem antibiotic, for its antibacterial activity, tissue penetration, clinical efficacy and bacteriological effect in obstetric and gynecological infections, and obtained the following results. 1. Antibacterial activity: MICs of L-627 against 149 strains isolated from 80 patients in this clinical trial were examined and compared with those of imipenem (IPM) and ceftazidime (CAZ). The MIC50 and MIC90 of L-627 against the isolates were 0.2 and 12.5 micrograms/ml, respectively. Those of IPM were 0.2 and 6.25 micrograms/ml, respectively. The antibacterial activity of L-627 was quite similar to that of IPM, and was superior to that of CAZ. 2. Tissue and retroperitoneal fluid penetration: The peak levels in venous and uterine arterial sera were 24.0 and 26.2 micrograms/ml, respectively, after 300 mg drip infusion. The peak levels in the uterine or adnexal tissues were 2.39-9.60 micrograms/g, and 0.2 microgram/g of L-627 was detected at 275 minutes after administration. Peak levels in retroperitoneal fluid were 8.7 +/- 1.7 micrograms/ml at 1 hour after the completion of 30 minutes drip infusion (300 mg) and 7.9 +/- 0.2 micrograms/ml at 30 minutes after 300 mg 60 minutes drip infusion (300 mg). These levels expected the MICs against main pathogenic organisms. 3. CLINICAL RESULTS: L-627 was given to the following 144 patients (No. of analytical subjects) at a daily dose of 0.3-1.2 g for 2-13 days: intrauterine infections (54), adnexitis (36), parametritis (17), pelvic peritonitis (27), bartholins abscess (6) and other infections (4). The clinical efficacy was 93.1% (134/144) and the eradication rate against isolated organisms was 88.7% (110/124). Side effects were observed in 2 patients: eruption (1) and vomiting with numbness of the tongue (1). Abnormal change in laboratory test results included increase in eosinophils in 1, increase in GOT, GPT and gamma-GTP in 1 and increase in GPT and A1-P in 1, but all of these abnormalities were very mild and withdrawal of the drug was not required. Our results suggest that this drug is useful in the treatment of gynecological infections.

Adolescent↗

PubMed1994

[A cytogenetic study of human oocytes unfertilized in in-vitro fertilization (IVF)].

A total of 260 unfertilized human oocytes obtained in our IVF program were studied cytogenetically, by a gradual fixation-air drying method proposed by Mikamo and Kamiguchi (1983). The oocytes were obtained from 72 cycles of 52 patients (mean age 32.1). Indications for these patients were 26 cases of tubal factor, 13 of male infertility, 2 of endometriosis and 11 of unexplained infertility. Ovulation induction was performed by hMG-hCG administration with GnRHa pretreatment. Of the 260 unfertilized oocytes, 183 displayed metaphase II and 149 were karyotyped accurately. There were 5 diploids (3.4%), 9 structural anomalies (6.0%) and 15 aneuploids (10.1%) including 8 hyperhaploids (5.4%) and 7 hypohaploids (4.7%). One hundred and twenty-two oocytes out of 149 (81.9%) were found to be normal haploids [23,X]. In 9 aneuploids, 5 showed the loss or gain of monads (so-called predivision), while 4 showed the loss or gain of dyads (so-called nondisjunction). Twenty-three oocytes out of 149 (15.4%) had one or more split dyads. (so-called nondisjunction). Twenty-three oocytes out of 149 (15.4%) had one or more split dyads. Our results were compared with those obtained in previous studies, and the importance of the chromosome preparation method in evaluating aberration frequencies was stressed. Causal mechanisms of aneuploidy, diploidy and structural anomaly were also discussed.

Adult↗

PubMed1993

Effects of platelet activating factor on human sperm function in vitro.

The direct effects of platelet activating factor (PAF) and the specific PAF receptor antagonist, CV-3988, on the fertilizing ability of human spermatozoa were investigated. PAF (10(-7)-10(-11) M) increased the human sperm penetration rates in a sperm penetration assay at all doses > 10(-11) M. In contrast, treatment of the spermatozoa with 10(-5) CV-3988 caused a significant decrease in human sperm penetration of zona-free hamster oocytes and adversely affected sperm motility after 24 h of incubation. This suppression was reversed by the addition of PAF. The acrosome reaction was also enhanced by PAF treatment of spermatozoa but this effect was not observed in calcium-free medium. While 10(-5) M CV-3988 decreased the acrosome reaction, the inhibition was also reversed by the addition of PAF. These results suggest that PAF may have a direct role in the fertilizing capacity of human spermatozoa. These findings also suggest that PAF may have a clinical application in an in-vitro fertilization programme.

Acrosome↗

PubMed1993

[Pharmacokinetic and clinical studies of flomoxef in the perinatal period].

Pharmacokinetic and clinical studies on flomoxef (FMOX) in the perinatal period were carried out and following results were obtained 1. The pharmacokinetic parameter T1/2's of FMOX in maternal serum, umbilical cord serum and amniotic fluid in mothers after single intravenous injection of 1 g (n = 46) and 2 g (n = 34) were 1.11, 9.24, 9.24 hours and 2.54, 12.49, 12.49 hours, respectively. Cmax's and Tmax's of umbilical cord serum and amniotic fluid were 12.71, 11.77 micrograms/ml and 0.57, 3.35 hours upon single dose of 1 g i.v., and 35.17, 12.37 micrograms/ml and 0.32, 3.42 hours upon single dose of 2 g i.v., respectively. 2. Clinical usefulness were evaluated in 93 cases including were various infections in pregnancy and puerperal period. In pregnancy cases, clinical efficacy rate was 95.5% (21/22), and 100% in puerperal period. Bacteriological response rate was 84.6% (eradicated: 29, decreased: 4, unchanged: 2, replaced: 4 and unknown: 8 cases). No severe side effects nor clinical laboratory test results were observed in any cases. From above basic and clinical results, we conclude that FMOX is a useful and safe agent for various infections in pregnancy and puerperal period.

Adult↗