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Biomedical subjects

K Okamura

Publications and source records attributed to K Okamura.

At least 253 records · Page 14Linked to original sources

[Two cases of continent cystoileostomy using nipple valve method].

We performed continent cystoileostomy in which the technique of Kock's efferent nipple was utilized, on two female patients with urethral cancer and vulvar cancer. We recommend continent cystoileostomy for the patient who needs urethrectomy but whose bladder function can be preserved.

Aged↗

[Power spectral analysis of spontaneous rhythm in peripheral blood flow in fetal lamb].

Fluctuations in fetal hemodynamic parameters are commonly observed, and we can use the variation in the fetal heart rate as an index in fetal assessment. The purpose of this study was to clarify the spontaneous rhythm in systemic circulation in fetal lambs by means of power spectral analysis. Three pregnant sheep and their fetuses at 125 and 135 days of gestation were surgically instrumented and studied. After a minimum recovery period of four days, a fetal electrocardiogram was taken and arterial blood pressure was recorded. They were also examined in the absence of heart rate variation by means of fetal cardiac pacing. We used an autoregressive model to estimate their power spectral densities. In normal fetal lambs, two spontaneous rhythms were detected in the spectra for the fetal heart rate and arterial blood pressure. Spectral analysis of arterial blood pressure variation in the absence of heart rate variation revealed that there was only one consistent major spectral component around 0.15 Hz. This suggests that fluctuations are caused not by a variation in the heart rate but by a variation in peripheral motor activity. This spontaneous rhythm in peripheral resistance may be associated with the sinusoidal heart rate pattern in the fetal cardiotochogram.

Animals↗

[Sex determination with a discriminant function analysis of deciduous teeth size in plaster models].

Plaster models of the teeth of 3-year-old Japanese children (96 males, 98 females) were used to record the crown length, crown width and crown thickness of 5 maxillary and 5 mandibular deciduous teeth (30 measurement values). These measurements were used to devise a number of sex determination formulae. A sex-determination formula using all 30 values was calculated. Furthermore, a number of practical formulae were derived from only the crown width and crown thickness values because the deciduous teeth wear in 4 years and older children rapidly progress, making the crown length measurement unreliable. These formulae were calculated for the maxillary teeth alone and mandibular teeth alone. The formulae based on only the crown width or thickness were also calculated for both maxillary and the mandibular teeth. A step-wise discriminant analysis was then used to ascertain the most reliable measurements and a practical formula subsequently devised. The results obtained were as follows: 1. The mean value for each measurement was greater in males than in females. 2. Significant differences in the values recorded were seen in 28 out of the 30 measurements taken. The measurement items not exhibiting these significant differences were the crown width of the maxillary lateral incisor and the crown thickness of the mandibular second molar. 3. The accuracy rates for the sex-determination analysis and the step-wise sex determination analysis calculated using all 30 values were 78.6% and 75.7%, respectively. 4. The accuracy ranges for the modified sex-determination formulae and the associated step-wise sex determination analyses were 70.6-78.4% and 67.0-76.8%, respectively.

Child, Preschool↗

Minocycline instillation for lymphorrhea after extraperitoneal pelvic lymphadenectomy. OFF.

We managed four cases of lymphorrhea after extraperitoneal pelvic lymphadenectomy by means of minocycline instillation into the cavity around the drainage tube. Two patients had concomitantly undergone cystectomy and one prostatectomy via the extraperitoneal approach. In all four cases, the lymphorrhea markedly subsided, which dramatically shortened the duration of drainage. No side effects occurred. These findings indicate that minocycline instillation is an efficacious treatment for lymphorrhea.

Administration, Intravesical↗

A case of radical resection for solid cystic tumor of the pancreas with widespread metastases in the liver and greater omentum.

Solid cystic tumor (SCT) of the pancreas is known to be a low-grade malignant tumor and distant metastasis is very rare. A 50-year-old Japanese female was hospitalized because of a large mass in the upper abdomen. Computerized tomography revealed a large calcified tumor in the body-tail of the pancreas, and multiple liver tumors. Abdominal angiography demonstrated the pancreatic tumor and multiple hepatic tumors as a hypervascular mass, and disclosed a small tumor stain in the branch of the right gastroepiploic artery. The patient underwent a distal pancreatectomy with splenectomy, extended right hepatic lobectomy, and removal of the omental metastases. Histopathological and electron microscopic studies made a definitive diagnosis of SCT. She is well without any signs of tumor recurrence 1 yr and 2 months after the operation. This may be the first patient receiving simultaneous radical resection for both the main tumor and widespread distant metastases.

Cysts↗

[A case of malignant paraganglioma].

Herein we report a case of paraganglioma. The metastatic lesion was incidentally found in a 64-year-old man by chest roentgenography. The primary tumor was extra-adrenal and was revealed to be malignant. The patient was normotensive without clinical symptoms despite extreme high serum and urinary dopamine levels. A venous injection of 5 mg metoclopramide elicited a significant increase of the blood pressure. This phenomenon disappeared after surgical excisions of the primary and metastatic lesions. The metoclopramide test is considered to be useful to diagnose asymptomatic paraganglioma.

Humans↗

[Dementia, daily activities and micturition of the elderly living in a nursing home].

This report shows the relation between daily activities, dementia and urinary disturbance. The subjects consisted of 44 males and 110 females with an average age of 80 years (ranged from 57 to 102). We evaluated the daily activities, underlying diseases, state of urination and the intelligence by the scale of Hasegawa. The persons with diapers had a higher degree of dementia than those who could go to the lavatory. As the degree of dementia aggravated, the incidence of urinary incontinence significantly increased. Urodynamic studies were performed on 49 persons who had urinary disturbance. There were 25 persons with normal vesical function, 16 with overactive vesical function, and 8 with underactive vesical function. Since all of the incontinent persons without dementia had abnormal vesical function, pharmacologic therapy was expected to be effective for them to improve incontinence. Half of the incontinent persons with dementia had normal vesical function. Mental and physical disabilities seemed to be the main factors causing incontinence in these persons. The multidisciplinary approach including medication, behavior treatment and awareness of the nursing staff is important and effective to reduce urinary incontinence.

Activities of Daily Living↗

Induction of human microvascular endothelial tubular morphogenesis by human keratinocytes: involvement of transforming growth factor-alpha.

Transforming growth factor-alpha(TGF-alpha), homologous to epidermal growth factor(EGF), is closely involved in hyperproliferation of human keratinocytes. Psoriasis is a common hyperproliferative skin disease characterized by hyperproliferation of keratinocytes and abnormal development of dermal capillary networks. In this study, we have examined whether keratinocytes could enhance angiogenesis. TGF-alpha or EGF efficiently stimulated formation of tubular-like structures of human omental microvascular endothelial(HOME) cells in type I collagen gels. Human keratinocytes produced TGF-alpha. To examine whether co-cultured keratinocytes could induce tubulogenesis of HOME cells in collagen gel, we have developed a co-culture system with human keratinocytes. Surprisingly, there appeared new development of many tubular-like structures of HOME cells in collagen gels when co-cultured with keratinocytes. This keratinocytes-dependent tubulogenesis was almost completely blocked when anti-TGF-alpha-antibody was present. The TGF-alpha molecules derived from keratinocytes appeared to enhance tubulogenesis of human microvascular endothelial cells. We propose the hypothesis that secretory TGF-alpha from human keratinocytes may promote an autocrine loop to proliferate the skin keratinocytes and also a paracrine loop to induce the skin angiogenesis.

Blotting, Northern↗

A model system for tumor angiogenesis: involvement of transforming growth factor-alpha in tube formation of human microvascular endothelial cells induced by esophageal cancer cells.

Tumor growth is dependent on angiogenesis, which is thought to be mediated through growth factors, such as transforming growth factor-alpha (TGF-alpha) and -beta (TGF-beta), epidermal growth factor (EGF), and basic fibroblast growth factor (bFGF), produced by tumor cells. We have developed a model system for tumor angiogenesis in vitro: tube formation of human omentum microvascular endothelial (HOME) cells in type I collagen gels when these cells are co-cultured with tumor cells. Exogenously added TGF-alpha induced tube formation of HOME cells in collagen gel. In contrast, TGF-beta inhibited the TGF-alpha-induced tube formation of endothelial cells. We investigated whether tube formation could be induced in HOME cells in collagen gel when the HOME cells were co-cultured with three esophageal cancer cell lines, TE1, TE2, and TE5. TE1 and TE2 cells expressed both TGF-alpha and TGF-beta mRNA, but the level of TGF-alpha mRNA in TE2 was found to be much lower than in TE1 cells. TE5 did not express either TGF-alpha or TGF-beta. The tube formation of HOME cell was induced when they were co-cultured with TE1 cells, while both TE2 and TE5 cell lines induced tube formation at much lower rates than TE1. TE1-induced tube formation of HOME cells was specifically blocked by co-administration of anti-TGF-alpha-antibody, but not by anti-bFGF-antibody. The present study suggests that, in our model system, esophageal tumor angiogenesis is partly controlled by TGF-alpha, possibly through a paracrine pathway.

Blotting, Northern↗

Induction of low density lipoprotein receptor and a transcription factor SP-1 by tumor necrosis factor in human microvascular endothelial cells.

We have previously reported that tumor necrosis factor-alpha (TNF-alpha) enhances expression of interleukin-6, collagenase, plasminogen activator inhibitor-1, and basic fibroblast growth factor genes in human omental microvascular endothelial (HOME) cells in culture. In this study, we found that treatment of HOME cells with TNF-alpha or interleukin-1 (IL-1) caused enhanced expression of low density lipoprotein (LDL) receptor. A few-fold increase in both LDL binding activity and the receptor mRNA levels was observed when HOME cells were treated with either TNF-alpha or IL-1. Northern blot analysis showed that cellular expression of LDL receptor gene was significantly increased 12-24 h after exposure to TNF-alpha. No significant changes in the life-span of LDL receptor mRNA were observed in untreated and TNF-alpha-treated cells. Scatchard analysis showed an increased receptor number for LDL in TNF-alpha-treated cells. Parallel to increased LDL binding activity, internalization and degradation of LDL were also increased in HOME cells treated with TNF-alpha or IL-1. TNF-alpha-induced enhancement of LDL receptor gene expression was not observed when cycloheximide was present. Cellular mRNA level of SP-1 gene was increased about 3-4-fold at 12 h after treatment with TNF-alpha. Nuclear run-on assays showed increased transcription of LDL receptor gene as well as SP-1 gene by TNF-alpha. Gel retardation assay with the SP-1 consensus fragment showed that SP-1 binding activity was increased about 4-5-fold 12-24 h after treatment with TNF-alpha. NF-kB binding activity was also dramatically increased, but there is no NF-kB motif on the promoter for LDL receptor gene. The induction of LDL receptor by TNF might be mediated through a transcription factor, SP-1.

Base Sequence↗

Synthesis and antiulcer activity of N-substituted N'-[3-[3-(piperidinomethyl)phenoxy]propyl]ureas: histamine H2-receptor antagonists with a potent mucosal protective activity.

As an aim toward developing new antiulcer agents, new N-substituted N'-[3-[3-(piperidinomethyl)phenoxy]propyl]ureas were synthesized and evaluated for histamine H2-receptor antagonistic, gastric antisecretory, and gastric mucosal protective activities. A QSAR study showed that the most favorable N-substituents were electron-donating straight-chain alkyl groups of short length such as ethyl group from the viewpoint of dual action, i.e., gastric antisecretory and mucosal protective actions. Among the ureas studied, compounds 4, 5, and 8-10 were selected as candidates for further study.

Animals↗

Decreased response to epidermal growth factor during cellular senescence in cultured human microvascular endothelial cells.

We have previously demonstrated that epidermal growth factor (EGF) induces cell migration, tissue-type plasminogen activator synthesis, as well as tubular formation in microvascular endothelial cells from human omental tissue. In this study, we compared the responsiveness to EGF of late passaged (senescent) human omental microvascular endothelial (HOME) cells with that of early passaged (young) HOME cells. We have employed HOME cells derived from surgically resected omental samples from 14 patients. EGF-stimulated cell migration significantly more in the young cells than in the senescent cells during serial cultivation (aging) in vitro. Scatchard analysis demonstrated that the number for both high and low affinity receptors for EGF in HOME cells was decreased dramatically during serial cultivation. The expression of EGF receptor mRNA was also decreased in the senescent HOME cells. Treatment of HOME cells with EGF significantly increased cellular mRNA levels of tissue-type plasminogen activator, and two protooncogenes, c-fos and c-myc, in young HOME cells, but not in senescent HOME cells. Thus HOME cells aged in vitro show a decreased responsiveness to EGF, resulting in decreased migration of human endothelial cells. The serial cultivation of human endothelial cells in vitro may downregulate EGF receptor and decrease responsiveness to exogenous EGF, a potent angiogenic factor.

Blotting, Northern↗

The outcome of pregnancy and prenatal chromosomal diagnosis of fetuses in couples including a translocation carrier.

In order to evaluate the relation between chromosomal translocation and the outcome of pregnancy, 50 couples were examined. Subjects consisted of 35 couples that included a reciprocal translocation carrier; 13 included a Robertsonian translocation carrier and 2 included a carrier of a mosaic reciprocal translocation. The reasons for performing chromosomal examinations were mainly infertility and abnormality of neonates. The rates of miscarriages and neonatal abnormalities in prior pregnancies were significantly higher than the birth rate of morphologically normal newborns. The presence of a translocation is closely related to reproductive failure because of the chromosomal imbalance. However, prenatal chromosomal examination after the 15th gestational week in subsequent pregnancies revealed that almost half of the fetuses showed normal karyotypes and only 12.8 per cent of the fetuses showed a chromosomal imbalance. Many chromosomally imbalanced fetuses are spontaneously aborted before amniocentesis. The risk of chromosomal imbalance is relatively low in prenatal diagnosis, but partial trisomies of small rearrangements tend to be preserved.

Adult↗

Change in electrocardiogram T-wave amplitude during umbilical cord compression is predictive of fetal condition in sheep.

OBJECTIVE: The purpose of this study is to assess the usefulness of the dynamic change in T/QRS ratio in fetal electrocardiograms in predicting the fetal condition when repetitive variable decelerations are seen in intrapartum cardiotocograms. STUDY DESIGN: We investigated the relationship, using linear regression and Wilcoxon's test, between T/QRS and blood gas values, catecholamine concentrations, and blood pressure during repetitive cord compression in five chronically instrumented lamb fetuses. RESULTS: T/QRS during cord compression correlated significantly (p less than 0.01) with fetal arterial pH (r = -0.7711), norepinephrine concentration (r = 0.7551), and duration of elevated blood pressure during compression (r = -0.8619). Fetal arterial pH and base excess were lower, the duration of elevated blood pressure during compression was shorter, and carbon dioxide partial pressure and catecholamine concentrations were higher in the stage with higher (greater than 0.50) T/QRS during compression (p less than 0.005). CONCLUSION: We can estimate the severity of fetal distress by measuring T/QRS near the bottom of the decelerations.

Animals↗