Search PubMed⌕ Search

Biomedical subjects

K Okamura

Publications and source records attributed to K Okamura.

At least 235 records · Page 13Linked to original sources
PubMed1993

Sonographic findings and fetal chromosomal studies undertaken prenatally by fetal blood sampling using cordocentesis.

Prenatal karyotyping was carried out on 206 pregnancies with sonographic abnormalities, including fetal malformations, growth retardation and disorders of the amniotic fluid volume. Overall, chromosomal aberrations were detected in 37 cases (18.0%), but the frequency of chromosomal aberrations was 8.2% in fetuses with a single anomaly and 52.7% in fetuses with multiple anomalies. The chromosomal risk was very high in malformations associated with growth retardation (81.8%) or with both growth retardation and disorders of the amniotic fluid volume (82.4%). High rates of chromosomal aberrations were observed in cases of heart anomalies, diaphragmatic hernia, urinary tract obstruction, hydrocephalus, intestinal atresia, abdominal wall defect and fetal effusion/hydrops. In fetuses at high risk of chromosomal aberrations, cordocentesis for rapid karyotyping is justified in the second or third trimester.

Journal Article↗
PubMed1993

Expansion of genes that encode MHC class I molecules in cyprinid fishes.

We have analyzed the genomic genes and the mRNA that encode MHC class I molecules in cyprinid fishes, namely, the ginbuna crucian carp (Carassius auratus langsdorfii) and the carp (Cyprinus carpio). The presence of several distinct class I genes was revealed in the genome of cyprinid fishes, and distinct class I genes that are expressed in carp cells were identified. The sequences of the alpha 3 domain of these class I genes are relatively well conserved, whereas the sequences of the respective alpha 1 and alpha 2 domains have diverged from one another. A comparison of the sequences expressed in carp with the sequences of the human classical class I molecules revealed that several amino acids in the peptide-binding region, including those that have been proposed to interact with antigenic peptide termini, are highly conserved. The present study demonstrated a dynamic expansion of the genes that encode MHC class I molecules in teleost fish whose ancestor branched off from the vertebrate line leading to mammals more than 400 million years ago.

Amino Acid Sequence↗
PubMed1993

Hormonal and metabolic effects of neuroglucopenia.

We examined the role of central neuroglucopenia, induced by intracerebroventricular (i.c.v.) administration of 2-deoxyglucose (2-DG), on glucose and amino acid kinetics in conscious dogs. Group 1 received i.c.v. 2-DG at 2.5 mg.kg-1 x min-1 for 15 min. Group 2 received an equal intravenous (i.v.) amount of 2-DG. In the i.c.v. group, plasma glucose levels rose from 106 +/- 4 mg/dl to a peak of 204 +/- 12 mg/dl by 90 min. Blood lactate increased from 689 +/- 1 to 2,812 +/- 5 mumol/l and blood alanine not change from basal (256 +/- 41 mumol/l). The rate of hepatic glucose production, determined isotopically, was increased 2-fold over basal (P < 0.01). Significant increases (P < 0.001) over basal were also noted in plasma epinephrine, norepinephrine, insulin, glucagon and cortisol. Leucine rate of appearance (Ra) showed a 30% decrease from basal to 2.4 +/- 0.05 mumol.kg-1 x min-1 (P < 0.01). In group 2 plasma glucose levels were not altered but plasma cortisol and glucagon showed a modest transient increase above basal (P < 0.05). No significant changes were noted in amino acid kinetics. These findings suggest that periventricular neuroglucopenia, in the absence of peripheral glucose deprivation, is accompanied by hyperglycemia secondary to enhanced hepatic glucose production with decreased glucose utilization and by increased hepatic uptake of gluconeogenic precursors. These, however, were not accompanied by increased whole body proteolysis as was previously seen with generalized glucopenia resulting from insulin-induced hypoglycemia.

Alanine↗
PubMed1993

Irsogladine is a potent inhibitor of angiogenesis.

We describe a novel inhibitor of angiogenesis, Irsogladine, an anti-ulcer drug. Irsogladine inhibited plasminogen activator synthesis of, and tube formation by, human microvascular endothelial cells in type 1 collagen gel treated with an angiogenic growth factor, EGF. Furthermore, Irsogladine administered orally significantly inhibited in vivo angiogenesis in mice. Irsogladine may be useful in the treatment of diseases associated with angiogenesis.

Animals↗
PubMed1993

Indispensable role of tissue-type plasminogen activator in growth factor-dependent tube formation of human microvascular endothelial cells in vitro.

Epidermal growth factor (EGF) stimulates the migration and proliferation of, and tissue-type plasminogen activator (tPA) synthesis in, human omental microvascular endothelial (HOME) cells in culture, as well as inducing the formation by these cells. In the present study, we examined the effects of various growth factors, i.e., transforming growth factor-alpha (TGF-alpha), insulin-like growth factor 1 (IGF-1), and hepatocyte growth factor (HGF) on HOME cells, and compared their effects with that of EGF. IGF-1 stimulated the proliferation and migration of these cells at a level comparable to EGF. EGF and TGF-alpha induced expression of tPA in HOME cells, while IGF-1 and HGF did not. EGF and TGF-alpha induced tube formation by HOME cells in type I collagen gel, while IGF-1 and HGF did not. The stimulatory effect of EGF on tube formation in the gel was blocked by anti-tPA antibody and by a serine protease inhibitor, aprotinin. When exogenous tPA and IGF-1 or HGF were added simultaneously to the culture, a marked induction of tube formation in the gel was observed. Exogenously added tPA alone, however, had no such inducible effect on tube formation. These results indicated an indispensable role of tPA in growth factor-dependent tube formation by HOME cells. Two subsets of growth factors appeared to modulate angiogenesis: One with fully active angiogenic activity which could induce PA (this included EGF and TGF-alpha), and the other, which could not induce PA and was not angiogenic, but could promote angiogenesis in the presence of PA. This subset included IGF-1 and HGF.

Cell Division↗
PubMed1993

Comparison of nucleotide sequences from upstream of the DQ52 gene to the S mu region of immunoglobulin heavy-chain gene loci between Suncus murinus, mouse and human.

The nucleotide sequence of a 4621 base pair fragment of DNA, from a position upstream of DSQ52 to the S mu region within immunoglobulin heavy-chain gene loci of Suncus murinus was determined. The sequence contained one D gene, three JH genes and an enhancer. Suncus murinus is an insectivore and is one of the most primitive mammals. Both primates and rodents are thought to have originated from insectivores and to have evolved separately. We also determined the nucleotide sequence of a region between human JH genes and the enhancer which has not previously been reported. Thus, the sequences of the entire region from each of the three species, Suncus murinus, human and mouse are now available. Comparison of the nucleotide sequence of this region between these three species indicated that D and JH genes, consisting of coding and signal regions, are highly conserved. Moreover, although extensive sequence homology in the region between JH and S mu was observed between mouse and human, only core portions of the enhancer region of Suncus murinus exhibited homology to those of mouse and human. Sequence conservation of JH genes in Suncus murinus, mouse and human was observed not only at the amino-acid level, but also at the nucleotide level, including the third letters of the codons. It is suggested that JH genes may play a role in the metabolism of the DNA and/or RNA.

Algorithms↗
PubMed1993

A reconsideration of surgery for mitral stenosis based on the extent of valvular distortion shown by two-dimensional echocardiography preoperatively.

A twelve-year follow-up study was carried out with 98 consecutive patients operated on for pure mitral stenosis with open mitral commissurotomy (OMC) or valve replacement with porcine valves (MVR). Each patient had the extent of valve distortion diagnosed preoperatively by two-dimensional echocardiography as either grade I of the dome-formation type, grade II of the intermediate type, or grade III of the mass-formation type. Thirty grade I patients and 24 grade II patients underwent OMC and 44 grade III patients received MVR. The long-term survival and reoperation rates were significantly poorer with grade II than grade I patients and there was no statistical significance between grades II and III. However, the clinical conditions set by NYHA are significantly worse in grade II than in grade III. This can be clearly explained by the fact that the left atrial volume decreasing ratio (LAVDR) in the latest period, which was measured in patients with more than 7 years survival, remained nearly at the early postoperative value in grade III, while the LAVDR of grade II at the latest period grew worse and became insignificantly different from the preoperative values. This study clearly shows that when OMC is applied to grade II patients, frequent reoperations might be necessary because of poor hemodynamic conditions. Thus, it might be better to adopt MVR rather than OMC with grade II patients with moderately distorted mitral valves.

Actuarial Analysis↗
PubMed1993

A case of a female infant with simultaneous occurrence of de novo terminal deletions on chromosome 14q and 20p.

This is a case report on an infant with de novo terminal deletions on the long arm of chromosome 14 and on the short arm of chromosome 20 [46, XX, del(14)(q32)del(20)(p11)]. Examination revealed that the infant had a peculiar face, a cleft and high palate, abnormal dentition, butterfly-like vertebral defects, finger anomalies, a simian line on the left hand, talipes equinovarus, deep plantar furrows, abnormally high values of alkali phosphatase and lactate dehydrogenase, mild anemia and psychomotor retardation. Comparing the present case with previously reported cases of a single deletion on chromosome 14q or chromosome 20p, the infant showed some symptomatic and dysmorphic features of both deletions.

Abnormalities, Multiple↗
PubMed1993

Induction of vascular endothelial tubular morphogenesis by human glioma cells. A model system for tumor angiogenesis.

We have developed two different models of tumor angiogenesis by human brain tumors: one being tube formation by bovine aortic endothelial (BAE) cells cocultured with tumor cells in vitro, and other being in vivo angiogenesis in mice when tumor cells are transplanted into the dorsal sac. We investigated whether tube formation could be induced in BAE cells in type I collagen gel when these cells were cocultured with seven human glioma cell lines. Four of the seven glioma cell lines, which had high levels of basic fibroblast growth factor (bFGF) mRNA, induced tube formation by BAE cells. The tube formation was blocked by coadministration of anti-bFGF antibody. In in vivo model system of tumor angiogenesis in mice, these four cell lines were highly angiogenic. In contrast, with the other three glioma cell lines, which had poor expression of bFGF, BAE cells showed no apparent tube formation. These three cell lines did not efficiently develop capillary networks in mice. The results demonstrated a correlative relationship in the tubulogenesis of BAE cells, bFGF mRNA levels and angiogenesis in mice. The present study with two model systems of tumor angiogenesis suggests that the angiogenesis of some human glioma cell lines is mediated by bFGF, possibly via paracrine control.

Animals↗
PubMed1993

Cloning and nucleotide sequences of two genes involved in the 4''-O-acylation of macrolide antibiotics from Streptomyces thermotolerans.

A DNA fragment responsible for the 4''-O-acylation of macrolide antibiotics was cloned from a mutant strain of the carbomycin producer Streptomyces thermotolerans. The gene encoding the macrolide 4''-O-acyltransferase was within a 2.7-kb region of the cloned fragment (15-kb). Streptomyces lividans carrying the region converted exogenously added tylosin to 4''-O-acyltylosins. Nucleotide sequencing of the region showed two open reading frames (ORFs). Expression assay using deleted plasmids showed that both ORFs were essential for optimal expression of the acyltransferase activity. One of them (acyB1) was identical with carE reported previously as a gene encoding 4''-mycarosyl isovaleryl-CoA transferase. The other (acyB2) was assumed to encode a novel regulatory protein that could active acyB1 expression. acyB1 and acyB2 were highly conserved among streptomycetes with macrolide 4''-O-acyl transferase activity.

Acylation↗
PubMed1993

The incidence of vertical transmission of hepatitis C virus.

This study was undertaken to clarify the incidence of the vertical transmission of hepatitis C virus (HCV). During the third trimester, 2015 pregnant women were examined as to anti-HCV antibodies. Anti-HCV antibody seropositive women were examined for HCV-RNA in peripheral blood at labor and in breast milk. Their offspring were also examined for HCV-RNA in umbilical cord blood and peripheral blood one week after birth and during subsequent outpatient visits. The following results were obtained: (1) Twelve of the 2015 pregnant women (0.6%) were seropositive for anti-HCV antibodies; (2) Seven of the twelve women (58%) seropositive for anti-HCV antibodies were also seropositive for HCV-RNA; (3) Three newborns of the seven HCV-RNA seropositive women (43%) were found to have HCV-RNA in the cord blood; (4) In the three newborns HCV-RNA had disappeared from the peripheral blood within one month after birth; (5) Two of the seven HCV-RNA seropositive women (29%) had HCV-RNA positive breast milk; (6) The possibility of infection via breast milk was shown in one infant at ten months after birth. Based on these results, it is indicated that HCV vertical transmission is possible in more than half of the HCV-RNA seropositive mothers. However, because of the disappearance of HCV from the infants' peripheral blood, further following study is needed.

Base Sequence↗
PubMed1993

Niceritrol reduces plasma lipoprotein(a) levels in patients undergoing maintenance hemodialysis.

Lp(a) is an LDL-like lipoprotein carrying the apoprotein(a) glycoprotein and has recently been recognized to be an independent risk factor for coronary heart disease. We studied plasma Lp(a) levels in 40 patients undergoing maintenance hemodialysis (24 male, 16 female; aged 16-83 years). Fasting plasma Lp(a) levels were measured by an enzyme-linked immunosorbent assay. The median value of plasma Lp(a) concentrations in hemodialysis patients was significantly higher than that of the normal volunteers (26.0 +/- 2.7 vs. 10.8 +/- 3.7 mg/dL, p < .05). Lp(a) levels did not correlate with age, duration of hemodialysis, total cholesterol, triglyceride, HDL cholesterol, or LDL cholesterol. The 11 patients whose plasma Lp(a) concentrations exceeded 20 mg/dL received niceritrol, a prodrug of nicotinic acid, at a dosage of 500 mg t.i.d. for 4 weeks. The plasma Lp(a) levels were significantly lower after 4 weeks of treatment (38.3 +/- 4.2 vs. 31.5 +/- 3.2 mg/dL, p < .01).

Adult↗
PubMed1993

[Antibiotic prophylaxis for transurethral resection of the prostate--comparison of oral administration therapy with intravenous administration therapy].

To compare the prophylactic effect of oral and intravenous antibiotics against postoperative fever and urinary tract infection (UTI) after transurethral resection of the prostate (TUR-P), we conducted a multi-center prospective randomized study. The incidence of pyrexia over 38 degrees C was defined as the primary endpoint. One hundred and fifty patients with sterile urine before TUR-P were entered into this study. The patients were allocated randomly into the two arms; arm A cefotiam 4 g a day for 7 days, arm B tosufloxacin 300 mg a day for 7 days, based on the stratification into the 4 groups determined with/without preoperative indwelling catheters and with/without the history of preoperative UTI. Of these patients, 143 were eligible. We divided 124 patients without preoperative UTI and without indwelling catheters as the "low risk group", and the other 19 patients with preoperative UTI and/or with indwelling catheters as the "high risk group". In the low risk group, 9 patients out of 63 (14.3%) in arm A and 6 out of 61 (9.8%) in arm B had pyrexia during 7 postoperative days. The incidence of fever in arm B was 4.4% less than that in arm A and the 95% confidence limit was from -7% to 16%. In the high risk group, 4 out of 11 (36.4%) patients in arm A and none of 8 in arm B had fever but the difference was not significant. The incidence of post operative UTI in the low risk group on the 4 to 5, 9 to 12, 23 to 26 and 37 to 40 postoperative days was 8.3, 16.4, 25.0 and 23.9% in arm A and 6.7, 16.7, 29.6 and 36.7% in arm B, respectively. The prophylactic effect of oral administration of tosufloxacin is equivalent to that of the intravenous administration of cefotiam. The use of oral antibiotics is beneficial to reducing the cost of medication.

Administration, Oral↗
PubMed1993

[Measurement of serum PSA by DELFIA PSA kit and its application for mass screening. The Gunma Urological Oncology Study Group].

The significance of prostate specific antigen (PSA) measured by DELFIA PSA kit in the 1,177 serum samples examined by mass screening for prostate cancer was evaluated. All subjects were examined by questionnaire, digital rectal examination (DRE) and prostatic acid phosphatase (PAP) and the subjects in whom prostate cancer was suspected from abnormal DRE and/or elevated PAP were recommended to receive the secondary screening for the presence of prostate cancer. All serum specimens used for this study were kept in our serum bank. The cut-off value was investigated between non-cancer subjects (diagnosed as normal, voiding disturbance or BPH) and prostate cancer patients. When the cut-off value was 2.89 ng/ml, the sensitivity, specificity and accuracy as prostate marker was 80.6%, 90.0% and 89.4%, respectively. Therefore, the cut-off value was determined as 3.0 ng/ml. The significance of PSA was retrospectively evaluated compared to PAP in the subjects examined by our mass screening. Twenty eight of the 39 palpable prostate cancers which could not be detected from the PAP level were detected from the PSA level, namely the sensitivity of the detection using the PSA level is more excellent than that using PAP. However, the false negative rate obtained using PSA was high (30.3%) in the patients with stage B disease. The relationship among serum PSA concentration, prostate size estimated by DRE and age was investigated. PSA was increased with age and prostate size. This estimation should be confirmed by using an ultrasonography because the prostate size obtained by DRE is inaccurate as compared with that obtained by ultrasonography.

Adult↗
PubMed1993

[Right thoracotomy to approach mitral or tricuspid valve in reoperation].

Four patients underwent mitral valve re-replacement, and required tricuspid annuloplasty in two, through a right thoracotomy. There was no major postoperative morbidity and recovery was full and uneventful. The indications for selection of this approach were isolated mitral valve disease or combined tricuspid and mitral valve disease, severe adhesion between heart and sternum on CT scan, intact aortic valve and no severe reduction of respiratory function. We recommend right thoracotomy to approach atrioventricular valves in selected situations in patients for reoperations.

Aged↗