Biomedical subjects

T Okada

Publications and source records attributed to T Okada.

At least 451 records · Page 25Linked to original sources

PubMed1996

Purification of mast cells with an improved nonsynchronous flow-through coil planet centrifuge.

A method for cell purification was designed without using high-density media which may impair membrane receptors. Rat and mouse mast cells were separated with an improved nonsynchronous flow-through coil planet centrifuge. Peritoneal cells were suspended at a concentration of 2-3x10(7) cells/ml in conditioned RPMI 1640, supplemented with 50% heat-inactivated FCS and 0.32% sodium citrate. In each separation 3 ml of cell suspension were loaded into the coiled column and elutriated at 4 degrees C. Several conditions, including the centrifugal force, revolution/rotation ratio, density of separation media, flow speed, and designs of both coiled column and flow tubes, were examined and optimized for mast cell purification. Rat mast cells were separated at the purity of 99.2%, with an average yield of 40% under sterile conditions. Nearly 90% pure mouse mast cells were harvested, despite a very low population of mast cells available in murine peritoneal cells. Purified cells were morphologically intact and discharged granules by exocytosis as indicated by electron-microscopic observations. The average histamine release with antigenic specificity was 34 and 61%, in passive sensitization in vitro and in vivo, respectively. Mast cells sensitized with mouse monoclonal IgE antibody released histamine, similar to cells sensitized with homologous antibody. This newly devised method of cell separation will be useful to purify biologically intact mast cells.

Animals↗

PubMed1996

Sialyl Lewis X analog inhibits eosinophil accumulation and late asthmatic response in a guinea-pig model of asthma.

Preferential eosinophil accumulation is characteristic of airway inflammation in asthma. Although little is known about its mechanism, the effect of a sialyl Lewis X analog on airway eosinophilia was examined in a guinea-pig model of asthma. Guinea-pigs were sensitized by repeated inhalation of ovalbumin. After a single inhalation challenge, the animals showed striking airway eosinophilia and a late asthmatic response. In contrast, when guinea-pigs were pretreated intravenously with sialyl Lewis X analog (LX 0104) 1 h before antigen challenge, both eosinophil infiltration in the tracheal wall and the late asthmatic response were significantly inhibited in a dose-dependent manner. In a further in vitro study, LX 0104 significantly suppressed the adhesion of human and guinea-pig eosinophils to human umbilical vein endothelial cells activated with interleukin-1 beta. These results suggest that LX 0104 plays a critical role in antigen-induced airway eosinophilia and the late asthmatic response.

Animals↗

PubMed1996

Monthly urinary gonadotropin and ovarian hormone excretory patterns in normal girls and female patients with idiopathic precocious puberty.

To identify the developmental changes in monthly urinary gonadotropin and ovarian hormone excretion, consecutive 30-d first morning void urinary specimens were collected from 36 normal girls, one normal woman, and 15 female patients with idiopathic precocious puberty. Of these children, three normal girls and three patients with precocious puberty volunteered to collect these specimens on 2-3 occasions over a time interval of 0.5-3.2 y. When sampled, six were early prepubertal, nine late prepubertal, eight early pubertal, eight mid-pubertal, and eight late pubertal normal girls, and six were early pubertal and 14 mid-pubertal patients with precocious puberty. The mean level of monthly urinary LH, FSH, and total estrogen excretions increased with pubertal maturation. In prepuberty, the mean LH level was lower than the mean FSH level, and neither showed significant episodic fluctuations. In early puberty, mean FSH levels increased with remarkable fluctuations, and mean LH levels were low with few variations in the course of a month. At the onset of puberty, gonadotropin excretory patterns underwent specific changes, showing at the same time periodically and every other day fluctuating patterns. Urinary total estrogen and pregnanediol excretion fluctuated independently from these periodic variations in urinary gonadotropins. These patterns were observed in six out of 16 patterns in normal pubertal girls and 10 out of 20 patterns in precocious puberty. Once the urine LH level exceeded the urine FSH level, however, these periodic variations disappeared. The cycle of a normal postmenarcheal girl aged 14 y showed a pattern similar to that of a normal adult. In patients with precocious puberty, the hormonal patterns were similar to those of sexual stage-matched normal girls.

Adolescent↗

PubMed1996

Endothelin-A receptor-mediated prostanoid secretion via autocrine and deoxyribonucleic acid synthesis via paracrine signaling in human bronchial epithelial cells.

It is known that serum promotes squamous differentiation of airway epithelial cell culture in vitro. We investigated which types of epithelial cells produce endothelins (ETs) and ET-evoked cellular responses in cultured human bronchial epithelial cells (HBECs). Squamous cells, not basal cells (nondifferentiated), secrete ET-1 actively. Specific binding of [125I]ET-1, not [125I]ET-3, was observed in squamous as well as basal cells, demonstrating the existence of only the ETA receptor. ET-1 together with epidermal growth factor stimulated synergistic DNA synthesis in basal cells, whereas ET-1 alone did not. Serum failed to induce DNA synthesis in HBECs, indicating terminal differentiation into squamous cells. ET-1 (1-100 nM) dose-dependently stimulated PGE2 (0.6-2.8 ng/10(5) cells) and thromboxane B2 release (4-30 pg/10(5) cells) from squamous HBECS, but not from basal cells. Western blot analysis showed that both squamous and basal HBECs expressed inducible and endothelial nitric oxide synthase, whereas ET-1 failed to stimulate nitric oxide synthase expression. Our findings suggest that secreted ET-1 from squamous cells evokes the release of prostanoids in an autocrine manner, and stimulates DNA synthesis in basal cells as a comitogen in a paracrine manner. Thus, it is likely that ET-1 secreted from HBECs plays an important role as a local, autocrine, and paracrine modulator in airway responses.

Azepines↗

PubMed1996

Synthesis and pharmacological evaluation of N-(6-functionalized-amino-3-pyridyl)-N'-bicycloalkyl-N''-cyanoguanidine s as antihypertensive agents.

A series of amino acid conjugates of N-(6-amino-3-pyridyl)-N'-[exo-bicyclo[2.2.1]hept-2-yl]-N''- cyanoguanidine (4) were prepared and evaluated as antihypertensive agents. The parent compound 4 showed potent potassium channel-opening and antihypertensive activities, but with undesirable changes of the urinary balance of electrolytes. However, alanine and histidine congeners (9,19) reduced this undesirable side effect of 4 through improved pharmacokinetics without loss of antihypertensive activity. They also provided additional information on the structural requirements for pinacidil-type potassium channel openers.

Animals↗

PubMed1996

Leukopenia-inducing effect of a combination of a new 5-fluorouracil (5-FU)-derived drug, BOF-A2 (emitefur), with other 5-FU-derived drugs or BV-araU (sorivudine) in rats.

BOF-A2 (emitefur: 3-(3-[6-benzoyloxy-3-cyano-2-pyridyloxycarbonyl]benzoyl)-1-ethoxy- methyl-5- fluorouracil), a novel 5-FU (5-fluorouracil)-derived drug, was co-administered with other conventional 5-FU-derived drugs or BV-araU [sorivudine: 1-beta-D-arabinofuranosyl-(E)-5-(2-bromovinyluracil)] for 8 consecutive days to rats. BOF-A2 (6 or 8 mg/kg, p.o.) co-administered with other 5-FU-derived drugs elevated the plasma 5-FU concentration 3- to 23.3-fold and decreased the peripheral white blood cell (WBC). The percentage decreases of WBC by 5-FU (4 mg/kg, i.p.), UFT (16 mg/kg, p.o.), tegafur (FT; 16 mg/kg, p.o.), carmofur (HCFU; 15 mg/kg, p.o.), doxifluridine (5'-DFUR; 16 mg/kg, p.o.) and flucytosine (200 mg/kg, p.o.) were 25.7%, 31.9%, 70.3%, 32.0%, 58.6% and 30.0%, respectively, compared with each drug alone. On the other hand, these phenomena did not occur with BV-araU. These findings can be attributed to the fact that the inhibitory activity of CNDP (3-cyano-2,6-dihydroxypyridine) for 5-FU degradation (IC50: 6.3 x 10(-9) M) is potent and 6000 times greater than that of BVU [(E)-5-(2-bromovinyl) uracil], another inhibitor of 5-FU degradation.

Animals↗

PubMed1996

Effects of maternal uninephrectomy on the development of the proximal tubule in fetal rat kidney: morphometrical study.

The kidneys of fetal rats from uninephrectomized mothers were investigated morphometrically on days 18, 20, and 22 of gestation. Maternal uninephrectomy was performed on day 5. On days 20 and 22, the proximal tubular cell height in fetuses from uninephrectomized mothers was significantly lower than that in fetuses from sham-operated mothers. The luminal diameter, length and total volume of the proximal tubule were significantly larger in fetuses from uninephrectomized mothers than in those from sham-operated mothers. The total glomerular volume of mature type in fetuses from uninephrectomized mothers was significantly larger than that in fetuses from sham-operated mothers. On day 18, maternal uninephrectomy caused no significant difference in any kind of parameters used for the proximal tubule, but induced an increase in the total glomerular volume of immature type. These results suggest that maternal uninephrectomy stimulates morphological development of the proximal tubule in the fetal kidney.

Animals↗

PubMed1996

Changes in cerebral oxygenation and hemodynamics during obstructive sleep apneas.

OBJECTIVE: To evaluate changes in cerebral tissue oxygenation and blood volume during obstructive sleep apnea (OSA). METHODS: We studied eight men with moderate to severe OSA by near-infrared spectroscopy (NIRS) simultaneously with polysomnography during nocturnal sleep (five patients) and daytime naps (three). RESULTS: In all patients, a consistent decrease of oxyhemoglobin (OxyHb) and increases of deoxyhemoglobin and total hemoglobin (TotalHb) in the regional cerebral tissue were observed during the episode of OSA at every sleep stage. Changes in each hemoglobin and apnea duration were significantly (p<0.01) more remarkable during rapid eye movement (REM) sleep than non-REM (NREM) sleep. Significant correlations of changes in OxyHb and TotalHb during the apneic episode with apnea duration were found during both NREM and REM sleep (p<0.01). CONCLUSIONS: Since TotalHb is used as an indicator of blood volume in the NIRS technique and the venous return is reported to increase during OSA, it is assumed that cerebral blood flow (CBF) increases during the episode of OSA. Because a decrease in OxyHb was observed and brain activity is reported to decrease during OSA, it is supposed that oxygen supply to the brain tissue decreases rather than oxygen consumption in the brain increases. The results of this study indicate that possibly increased CBF could not compensate for reduced arterial oxygen saturation and cerebral tissue hypoxia may occur during the episode of OSA.

Adult↗

PubMed1996

Induction of superovulation by immunoneutralization of endogenous inhibin through the increase in the secretion of follicle-stimulating hormone in the cyclic golden hamster.

The present study was conducted to study the effect of immunoneutralization against endogenous inhibin on FSH, LH, oestradiol-17 beta and progesterone secretion and to investigate the effect of removal of endogenous inhibin on subsequent follicular development in the hamster. After treatment with anti-inhibin serum (inhibin-AS) at 1100 h on day 2 of the oestrous cycle (day 1 = day of ovulation), a marked increase in plasma levels of FSH and a slight increase in plasma levels of LH were noted and pituitary contents of FSH, but not LH, were also increased. In the group treated with inhibin-AS, superovulation occurred on day 1 of the following cycle. Plasma levels of oestradiol-17 beta markedly increased with the increase in the number of ovulations induced by human chorionic gonadotrophin (hCG) as compared with those in control animals. In the second cycle, plasma concentrations and pituitary contents of FSH in the animals given 200 microliters inhibin-AS still showed high values as compared with those in the animals treated with control serum, although superovulation did not occur on day 1 of the third cycle. Plasma concentrations and pituitary contents of LH in the hamster given 200 microliters inhibin-AS tended to decrease as compared with those in control animals during the second cycle. Plasma concentrations of oestradiol-17 beta in the animals treated with 200 microliters inhibin-AS changed in a similar way to controls. A marked increase in plasma concentrations of progesterone was noted on days 1 and 2 of the second cycle in the group receiving inhibin-AS. The twice daily injection of 1 IU hCG during the second cycle to the animals given 200 microliters inhibin-AS induced superovulation on day 1 of the third cycle. These results indicate that circulating inhibin may be an important indicator of the number of developing follicles and may maintain the species-specific number of developing follicles through suppression of FSH secretion in the cyclic hamster. They also suggest that high levels of inhibin slightly suppress plasma levels of LH, indicating that plasma LH may also regulate follicular development in the cyclic hamster.

Animals↗

PubMed1996

[Correlation between periventricular lucency and extracranial arterial lesions].

This study was done to clarify relationships between the degree of periventricular lucency (PVL), and lesions in the carotid arteries and the legs as detected with B-mode ultrasonography and the ankle pressure index, respectively. According to the distribution of PVL on computed tomography, 45 patients were divided into 2 groups: 22 patients with diffuse PVL (from the periventricular white matter to the subcortical area, DPVL group) and 23 patients with PVL localized in the frontal deep white matter (LPVL group). Plaque, defined as a thickened intima-media complex of 2.1 mm or more, was divided into two types; mural plaque and nodular plaque. Hypertension was more common in the DPVL group than in control groups, which consisted of 70 age-matched patients with cerebral thrombosis without PVL (CTH group) and 50 controls with neither PVL nor cerebrovascular lesions (NCT group). All patients in the DPVL group met the diagnostic criteria for Binswanger's disease proposed by Bennett DA. The incidence of low API indices (< 0.9) in the DPVL group (45%) was significantly higher than that in the NCT group, and it was slightly higher than that in the LPVL group. Carotid lesions, mainly nodular plaques, were seen in 82% of patients in the DPVL group and in 74% of those in the LPVL group; these percentages were significantly higher than those in the CTH (49%) and NCT (40%) groups. In particular, bilateral carotid lesions were more common in the DPVL group than in the other three groups. The degree of PVL correlated with lesions in the carotid arteries and the legs. These correlations suggest that the arterial lesions not only resulted from a risk factor (hypertension) for PVL, but also promoted PVL by causing extra- and intra-cranial arterial lesions. Furthermore, they imply that LPVL is a precusor to DPVL.

Aged↗

PubMed1996

[A case of sensitive urethra treated by continent vesicostomy using detrusor tube].

A case of sensitive urethra treated with continent vesicostomy is reported. She suffered from atonic bladder due to a previous pelvic surgery and could not continue clean intermittent self-catheterization because of pain and discomfort, or sensitive urethra. Continent vesicostomy using detrusor tube following Mitrofanoff principle was performed. Postoperatively, the daily life activity improved markedly. Mitrofanoff operation is considered to be applicable to the cases with sensitive urethra after sufficient explanation and consent.

Cystostomy↗

PubMed1996

Fine structure of the acinar and duct cell components in the parotid and submandibular salivary glands of the rat: a TEM, SEM, and HRSEM study.

Parenchymal and stromal components of the rat parotid and submandibular glands were examined by conventional and high resolution scanning electron microscopy (HRSEM). Freeze-fractured specimens were subjected to HCl and NaOH extraction procedures to better differentiate connective tissue and cellular components. In addition, the internal three-dimensional morphology of the secretory acinar cells and duct cells was revealed by maceration with a dilute osmium tetroxide solution to selectively remove some of the cytoplasmic components. SEM and HRSEM examination of the HCl-treated samples of both glands revealed a fine filamentous network immediately surrounding each acinus. Coarser bundles of collagen that linked neighboring acini were also observed. NaOH-extracted samples selectively removed the cellular components and showed more clearly the three-dimensional structure of the connective-tissue stroma. A dense-collagenous network surrounded each lobule while more internal regions consisted of a honeycomb-like pattern of evacuated spaces previously occupied by secretory acini. These spaces were smoothened in appearance and often interconnected. Apically-located secretory granules and profiles of the rough endoplasmic reticulum and Golgi apparatus in perinuclear regions were encountered in the acinar and duct cells of macerated samples by HRSEM. In addition, a phenylephrine-induced experimental condition performed in some rats resulted in a significant increase in secretory granule size and density of the serous cells.

Adrenergic alpha-Agonists↗

PubMed1996

Charge-affected transperitoneal movement of amino acids in CAPD.

Our objective was to investigate the influence of molecular charge on transperitoneal solute movement in continuous ambulatory peritoneal dialysis (CAPD). Tests of peritoneal equilibration were performed. Two liters of 2.27% or 2.5% glucose CAPD dialysate were infused and the dialysate samples were taken after 2 hr and 4 hr, and blood samples were obtained after 4-hr dwell time. Dialysate-to-plasma concentrations ratios (D/P) were calculated for creatinine (Cr) and three amino acids with almost the same molecular weight but quite different charges: glutamic acids (Glu: negatively charged), glutamine (Gln: near neutrally charged), and lysine (Lys: positively charged). The setting was a university hospital. There were 23 stable CAPD patients with a mean age of 56.6 +/- 9.5 years and a mean CAPD duration of 15.2 +/- 19.4 months. D/P ratio of Glu was much lower than those of Gln, Lys and Cr at both 2 hr and 4 hr (p < 0.01), and D/P of Lys was significantly lower than that of Gln (p < 0.01). There was no significant difference of D/P between Gln and Cr. The order of transperitoneal mobility among the three amino acids was Gln > Lys > Glu. Transperitoneal movement of solutes in CAPD is influenced by molecular charge, the movement of negatively charged solutes is most remarkably retarded in cases of amino acids.

Adult↗

PubMed1996

Acute sensorineural hearing loss caused by Mycoplasma pneumoniae.

Four cases with acute sensorineural hearing loss on one side and one case with bilateral ear fullness associated with Mycoplasma pneumoniae (MP) were described. These cases were characterized by highly elevated MP complement fixation titer, and cold hemagglutinin titer. All patients experienced cochlear symptoms in an early stage following common cold. In all cases, clarythromycin (CAM) had been administered for 10 days, and adenosine triphosphate (ATP), vitamin B1, B12, and prednisolone were concurrently administered for 14 days. Two cases with acute hearing loss and one case with ear fullness returned to normal hearing after treatment. The other cases were remarkably improved in hearing level. MP is a common causative agent for protein respiratory disease. The true incidence of hearing loss in this disease may be higher than has been reported so far. Prompt diagnosis possibly facilitates the administration of specific treatment and leads to good prognosis.

Adult↗

PubMed1996

Clinical significance of step stimulus-induced optokinetic nystagmus.

The optokinetic nystagmus (OKN) test has diagnostic values in that it can detect lesioned sites in patients with infratentorial lesions. The test has so far been performed by using angular acceleration to the final velocity over 100 degrees/s, which is time-consuming and inconvenient for patients. In the present study, we tried to modify and simplify the OKN test used previously to give step stimulus of constant stimulus and compared the results in 20 normal subjects. Slow-phase velocity versus stimulus velocity, and fast phase amplitude and peak velocity versus stimulus velocity of OKN were compared between step-stimulus OKN and linear-stimulus OKN. As a result, each parameter showed significantly higher values in step-stimulus OKN than in linear-stimulus OKN. Averaged slow-phase OKN velocity during the first 5 s is sufficient to calculate OKN velocity, and it requires only short time to perform.

Adult↗

PubMed1996

Primary position upbeat nystagmus with special reference to alteration to downbeat nystagmus.

A 24-year-old man was admitted to the University Hospital showing severe dehydration that might have been the result of medicine-induced gastritis. Wernicke's encephalopathy was suspected in this patient. On admission, primary position upbeat nystagmus (PPUN) was found. The patient showed tongue fasciculation and loss of gag reflex, which, however, soon returned to normal. Electronystagmographic (ENG) findings were suggestive of lesions in the brainstem. Based on neurological signs and symptoms, we concluded caudal brainstem lesions might be a possible site responsible for the upbeat nystagmus. This nystagmus, however, was later found to be reversed to downbeat nystagmus. This is considered to have been due to predominant differences in vertical velocity which are induced by gravity.

Brain Stem↗

PubMed1996

[Complete remission of steroid-resistant minimal-change nephrotic syndrome by cyclosporin after additional low-density lipoprotein apheresis treatment].

Steroid-resistant nephrotic syndrome (SRNS) is still difficult to treat in spite of the introduction of various immunosuppressive drugs. In recent years, low-density lipoprotein apheresis (LDL-A) has been used to treat SRNS, mainly on focal glomerular sclerosis (FGS), and some cases have shown amelioration of the nephrotic syndrome. We describe here a case of steroid-resistant minimal-change nephrotic syndrome (MCNS), which was also unresponsive to cyclosporin A (CsA), but attained remission after the additional LDL-A treatment. A 20-year-old man with MCNS was treated with prednisolone at the dose of 40 mg/day for 6 weeks, but his nephrosis continued. The administration of CsA (2.5 mg/kg/day) induced remission temporarily for 2 months. However his nephrosis soon recurred, and persisted without improvement in spite of an increase in the CsA dose (4.5 mg/kg/day). After 6 LDL-A treatments given concomitantly with the administration of CsA (5 mg/kg/day), the urinary protein excretion remarkably reduced, and the patient remained free of the disease. Although the precise mechanism of hyperlipidemia on CsA is still unknown, it can be speculated that the rapid improvement of hyperlipidemia by LDL-A might strengthen the effect of CsA, presumably through the increased cellular uptake of CsA. LDL-A might be useful for ameliorating steroid-resistant MCNS, which also is unresponsive to immunosuppressive drugs, such as CsA.

Adult↗

PubMed1996

Decrease of mesangial matrix after immunosuppressive therapy in children with reversible membranoproliferative glomerulonephritis type I.

We followed the course of membranoproliferative glomerulonephritis (MPGN) type I after immunosuppressive therapy in 10 children. At diagnosis all patients had abnormal urinary findings. After a mean follow-up of 14 years all but one patient showed normal urinalysis and renal function. Glomerular morphometry revealed an increase in the ratio of mesangial matrix area to glomerular area (M/G%) in all patients. After immunosuppressive treatment, a second biopsy was performed, which showed a significantly decreased M/G% in 4 patients. In 3 of the remaining 6, the mean M/G% was significantly lower in a third biopsy when compared with the first. In addition, there was a negative correlation between M/G% and duration from onset disease to biopsy (r = -0.46, p <0.05). Fifteen biopsies (6 initial and 9 repeat biopsies) were examined for the staining of various extracellular matrices. In the initial biopsy type IV collagen, type V collagen and fibronectin were increased in expanded mesangial areas. Type III collagen was found segmentally in a few biopsies only. M/G% correlated with the grade of type IV collagen, type V collagen and fibronectin staining. These findings suggest that a reversible clinical course of MPGN type I in children is paralleled by a decrease of mesangial matrix expansion.

Adolescent↗