Search PubMed⌕ Search

Biomedical subjects

Y Yamashiro

Publications and source records attributed to Y Yamashiro.

At least 127 records · Page 7Linked to original sources
PubMed1995

Amino acids and peptides. XXV. Preparation of fibronectin-related peptide poly(ethylene glycol) hybrids and their inhibitory effect on experimental metastasis.

Hybrids of fibronectin-related peptides [Arg-Gly-Asp (RGD), Arg-Gly-Asp-Ser (RGDS)] and poly(ethylene glycol) (PEG) were prepared and their inhibitory effects on experimental metastasis in mice were examined. The inhibitory effect of RGD was markedly potentiated by hybrid formation with poly(ethylene glycol) #6000. As to inhibitory effect, RGD was more potent than RGDS and RGD PEG hybrids were superior to RGDS PEG hybrids. Hybrid formation with PEG #6000 was more effective than that with PEG #4000.

Amino Acid Sequence↗
PubMed1995

Plasminogen activators in tissue extract of aural cholesteatoma.

Using a biochemical technique, the authors characterized and identified the plasminogen activator (PA) derived from tissue extracts of six aural cholesteatomas. The results of fibrin zymography indicated that the tissue extracts of two cholesteatomas demonstrated two lytic zones on fibrin-agarose plates. One of the lytic zones was at about 72 kd, while the other zone was at about 64 kd. Using various goat immunoglobulin G (IgG)-containing antibodies (anti-human uterine tissue type PA (t-PA), anti-human low-molecular-weight (LMW) urokinase, and nonspecific goat IgG) and plasminogen-free fibrin-agarose plates, we confirmed that the cholesteatoma tissue extracts contained 72 kd t-PA and 64 kd urokinase type PA (u-PA). Furthermore, we measured the t-PA and u-PA activities in the tissue extracts selectively by parabolic rate assay. In order to estimate the PA activity, we developed optimal conditions for this assay. The specific t-PA activity ranged from 0.03 to 0.43 mIU/micrograms-protein and the specific u-PA activity ranged from 0 to 0.35 mIU/microgram-protein. The highest percentage of u-PA with respect to the total PA activity was 44.9%. However, in four of the six cases, we failed to detect u-PA activity. In the present study, we thus clarified the presence of PAs in tissue extracts of aural cholesteatomas. Furthermore, we confirmed that measureable u-PA occurred in some tissue extracts. We anticipate that the u-PA in inflammatory tissues plays an important role in the degradation of the extracellular matrix via the formation of plasmin and collagenases.

Cholesteatoma, Middle Ear↗
PubMed1995

CPAP titration for sleep apnea using a split-night protocol.

We studied 107 patients with sleep-disordered breathing to confirm the effectiveness of continuous positive airway pressure (CPAP) titration using a split-night protocol. Patients spent two consecutive nights in our laboratory with complete polysomnography. On the first night, we applied a split-night protocol; the first half of the night was used as a baseline (B), and after a diagnosis was made, CPAP was applied during the second half of the night (SN). On the second night (2N), patients spent the entire night on CPAP to confirm the effectiveness of CPAP treatment. The SN and 2N both revealed a significant reduction in arousal index (37.8 +/- 27.9 on B, 13.2 +/- 12.1 on SN, 11.4 +/- 8.0 on 2N, values are mean +/- SD, p < 0.001), apnea hypopnea index (AHI) (23.6 +/- 26.3/h on B, 3.0 +/- 3.7/h on SN, 2.4 +/- 2.6/h on 2N, p < 0.001), percent total sleep time below 90% SaO2 (21.0 +/- 27.2% on B, 8.2 +/- 13.8% on SN, 4.9 +/- 10.2% on 2N, p < 0.001), and percent total sleep time below 80% SaO2 (1.1 +/- 3.8% on B, 0.0 +/- 0.1% on SN, 0.1 +/- 0.5% on 2N, p < 0.001). There were no significant differences between the SN and the 2N for these measurements. Final CPAP pressure was significantly lower at the end of the SN when compared with the 2N (8.8 +/- 2.7 cm H2O on SN, vs 10.3 +/- 2.8 cm H2O on 2N, p < 0.001). When patients were divided into three groups (AHI < 20, n = 69; 20 < AHI < 40, n = 18; AHI > 40, n = 20), the final CPAP pressure was different only in the group with AHI < 20 (8.1 +/- 2.3 cm H2O on SN, 9.6 +/- 2.3 cm H2O on 2N, p < 0.001). We conclude that a split-night protocol may be sufficient to determine the effective CPAP pressure, especially in patients with an AHI > 20.

Female↗
PubMed1995

The effects of posture change and continuous positive airway pressure on cardiac natriuretic peptides in congestive heart failure.

We studied changes in the peripheral plasma levels of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) in seven patients with congestive heart failure (CHF) during four 1-h protocols during which patients maintained either an upright or a supine posture with or without nasal continuous positive airway pressure therapy (N-CPAP) at a pressure of 10 cm H2O (FIO2 = 0.21). The mean plasma ANP concentration of patients increased significantly from baseline at the end of 1 h of recumbency (65.9 +/- 5.8 to 82.6 +/- 8.3 pg/mL (mean +/- standard error); p < 0.05). This increase was prevented by concomitant N-CPAP therapy (72.1 +/- 8.0 to 61.0 +/- 8.8 pg/mL; p = NS). The mean level of ANP decreased significantly (71.9 +/- 9.0 to 62.5 +/- 8.0 pg/mL; p < 0.05) while patients simply maintained an upright posture. A significant reduction was also observed when patients remained upright with accompanying N-CPAP (72.6 +/- 10.9 to 54.6 +/- 4.3 pg/mL; p < 0.05). There were no significant changes observed in the mean level of BNP for any of the protocols undertaken. We conclude that in patients with chronic CHF, (1) an increase in ANP concentration occurs with recumbency, and this can be prevented by N-CPAP therapy; (2) a decrease in ANP occurs with maintenance of an upright posture, and that this reduction may be augmented by N-CPAP; and (3) no net change in BNP concentration occurs with either posture change or N-CPAP.

Aged↗
PubMed1994

Docosahexaenoic acid status of patients with extrahepatic biliary atresia.

Docosahexaenoic acid (DHA) is believed to be an important long-chain polyunsaturated fatty acid (LCPUFA), which may be essential for neurofunction in infants. Patients with extrahepatic biliary atresia (EBA) may have DHA deficiency secondary to fat malabsorption. The authors investigated DHA and other LCPUFA levels in plasma and red blood cell (RBC) phospholipids of patients after the Kasai portoenterostomy and after supplementation with essential fatty acids. Ten children aged 8 to 17 months (mean, 12.6 months) comprised the study group. Five were jaundiced and five had a normal bilirubin level. The patients received 1 mL/kg of fat emulsions (10% Intralipid, containing 50% linoleic acid and 9% alpha-linolenic acid) in addition to an age-appropriate diet. Additional supplements were ursodeoxycholic acid (UDCA) (15 mg/kg/d) and taurine (100 mg/kg/d). The percentages of DHA in both plasma and RBC phospholipids of patients in the jaundiced group were significantly lower than those of normal children. Patients in the jaundice-free group had significantly lower levels of DHA and higher levels of linoleic acid in both plasma and RBC phospholipids in comparison to the normal group. This study shows that postoperative EBA patient become DHA-deficient even when supplemented with fat emulsions (largely composed of linoleic acid) that contain DHA's precursor, alpha-linolenic acid. This demonstrates a deficiency in the long-chain acid desaturase activity of these patients. It is recommended that excessive/linoleic acid intake be avoided and that all EBA patients have small amounts of DHA added to their lipid supplementation.

Biliary Atresia↗
PubMed1994

Effects of ursodeoxycholic acid treatment on essential fatty acid deficiency in patients with biliary atresia.

To assess whether ursodeoxycholic acid (UDCA) treatment has any beneficial effect on essential fatty acid (EFA) deficiency in patients who have had a Kasai operation for extrahepatic atresia (EBA), responses of serum fatty acids to UDCA administration (15 mg/kg/d) were investigated in eight jaundice-free patients and in eight patients with jaundice (serum total bilirubin > or = 1.0 mg/dL). All patients were also given taurine supplementation (100 mg/kg/d). Serum fatty acid composition was determined before and 6 months after UDCA treatment. Serum total bile acid concentration and serum total bilirubin value, as a part of conventional liver function tests, were measured before and during UDCA therapy. Before UDCA treatment, the concentrations of linoleic acid and arachidonic acid were significantly lower (P > .05 for the former; P > .01 for the latter) in both the jaundice and jaundice-free groups than in the controls. After 6 months of treatment, the linoleic acid concentration significantly increased (P > .05), to the normal range, in the jaundice-free group, but not in the jaundice group. The arachidonic acid concentration did not increase significantly in either group. The serum total bile acid concentration was lower in six of the eight jaundice-free patients and in four of the eight jaundice patients. The serum total bilirubin value decreased in six of the eight jaundice-free patients and in four of the eight jaundice patients; however, the degree of improvement was not statistically significant in either group. No side effects developed, and there were no changes in blood chemistry values unrelated to liver disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Arachidonic Acid↗
PubMed1994

Acute effect of nasal CPAP on periodic limb movements associated with breathing disorders during sleep.

Sleep-disordered breathing is commonly associated with periodic limb movements (PLMS). Nasal continuous positive airway pressure (nCPAP) is the most widely used treatment for sleep-disordered breathing. However, it is not clear whether nCPAP treatment of apnea also has a systematic effect on PLMS. We studied 15 patients with sleep-disordered breathing and PLMS in a split-night protocol in order to confirm the acute effects of nCPAP on PLMS. Although the PLMS index (PLMSI) did not change statistically (baseline, 38.7 +/- 20.5; CPAP, 31.3 +/- 17.0; p = ns), the PLMS-related index (PLMS-ArI) decreased significantly on nCPAP (baseline, 17.8 +/- 10.1; CPAP, 9.2 +/- 5.7; p < 0.05). Whether the reduced PLMS-ArI is sustained with chronic nCPAP is unknown and a matter of future investigation.

Adult↗
PubMed1994

Antimetastatic effects of synthetic peptides containing the core sequence of the type III connecting segment domain (IIICS) of fibronectin.

The antimetastatic activities of synthetic peptides corresponding to fragments of the adhesion-related molecules, such as fibronectin and laminin, were examined. We prepared three peptides derived from the type III connecting segment domain (IIICS) of fibronectin: Glu-Ile-Leu-Asp-Val (EILDV), Glu-Ile-Leu-Asp-Val-Pro-Ser-Thr (EILDVPST), Arg-Glu-Asp-Val (REDV), and a laminin-related peptide, Tyr-Ile-Gly-Ser-Arg (YIGSR). Each peptide inhibited the experimental tumor metastasis of B16-BL6 melanoma, while EILDV had the strongest effect. The peptides conjugated with poly(ethylene glycol) (PEG) were more effective than the unmodified peptides in molar ratio terms. A mixture composed of PEG hybrids with EILDV, REDV and YIGSR significantly inhibited tumor metastasis.

Amino Acid Sequence↗
PubMed1994

Impaired increase of prostaglandin E2 in gastric juice during steroid therapy in children.

To investigate the aetiology of steroid-induced peptic ulcers in children, prostaglandin E2 (PGE2) release and acid secretion into gastric juice was evaluated in 10 children receiving a corticosteroid before and after injection of pentagastrin. The concentration of luminal PGE2 was measured by radio-immunoassay. The basal levels of PGE2 concentration and acid secretion in gastric juice did not differ significantly between the steroid therapy group and control group. After stimulation with pentagastrin, acid secretion increased significantly (P < 0.01) in both groups and PGE2 concentration increased significantly (P < 0.01) only in the control group. Prostaglandin E2 concentration was significantly lower in the steroid therapy group than in the control group 20-40 and 40-60 min after pentagastrin stimulation (P < 0.01 and P < 0.05, respectively). Since PGE2 has a cytoprotective effect on the gastric mucosa, the results of impaired increase of PGE2 in response to increased acid secretion during steroid therapy may indicate causality with the development of steroid-induced peptic ulcers.

Adolescent↗
PubMed1994

Helicobacter pylori colonization in children with gastritis and peptic ulcer. I. The colonization rate and effects of colonization on mucin content and mucosal inflammation in the antrum.

The incidence of Helicobacter pylori infection and effects of H. pylori colonization on mucin content and mucosal inflammation of the antral mucosa were studied quantitatively in 55 Japanese children with suspected gastritis and peptic ulcers (aged 6-16 years, mean 12.3 years). H. pylori was detected, using Warthin-Starry stain, in nine of the 22 cases (41%) with antral histological gastritis, but in none of the 33 histologically normal cases. Five out of seven duodenal ulcer cases showed histological gastritis, and all five cases were H. pylori positive. Severity of gastritis, evaluated by means of gastritis score, was significantly higher in H. pylori positive gastritis cases than in H. pylori negative gastritis cases (5.4 +/- 1.0 vs 3.1 +/- 0.3, P < 0.001). A PAS-AB index, a proportion of the periodic acid Schiff-alcian blue (PAS-AB) positive mucin area to the total epithelial area, was significantly lower in H. pylori positive cases than in H. pylori negative cases, irrespective of the existence of histological gastritis (23.5 +/- 7.6% vs 40.4 +/- 5.5%, 43.5 +/- 4.2%, P < 0.001). The decreased mucin content of gastric mucosa is likely to lead to weakening of an important defensive factor of gastric mucosa. These findings suggest that H. pylori plays an important role in gastritis and peptic ulcers in children, especially in cases with duodenal ulcer.

Adolescent↗
PubMed1994

Helicobacter pylori colonization in children with gastritis and peptic ulcer. II. Ultrastructural change of the gastric mucosa.

To evaluate the role of Helicobacter pylori in the pathogenesis of gastritis and peptic ulcer in children, ultrastructural changes of the gastric mucosa with H. pylori colonization were studied in two pediatric patients with duodenal ulcers. The study demonstrated that H. pylori: (i) colonized the mucous layer covering normal gastric epithelium; (ii) lay atop short, irregular microvilli and at the intercellular junctions of damaged cells; and (iii) adhered firmly by specific junction zone (firm connection) and loosely by filamentous appendages to the epithelial surfaces of cells which lacked evidence of a protective mucous layer. The ultrastructural changes, which become progressively worse from patterns (i) to (iii) mentioned above, suggest that these patterns represent distinct and successive stages of the infection. These findings, therefore, lend support to the notion that H. pylori infection is quite common and may relate to the pathogenesis of gastritis and peptic ulcer in children as well as in adults.

Child↗
PubMed1994

A new oral margarine loading test in children.

Margarine (2g/kg) was orally administered to 39 children with normal fat digestion and absorption (control group) and 17 children with abnormal fat digestion and absorption (malabsorbed group). The serum triglyceride (TG) level was serially determined by capillary blood sampling. In the control group, the TG level was significantly elevated after 2, 3 and 4 h as compared with the level before margarine ingestion (basal TG). The maximum TG elevation rate [MTER = (maximum TG-basal TG)/basal TG x 100] was > 50% in all but three children. In contrast, a significant increase in TG was not observed in the malabsorbed group after margarine ingestion, and the MTER was < 50% in all but two children. The MTER was significantly lower in children with a high microscopic score of fecal fat than that in children with a low score. This oral margarine loading test is a simple and semi-quantitative evaluation of fat digestion and absorption, and is considered to be useful for the assessment of the presence or severity of fat maldigestion and malabsorption in children.

Adolescent↗
PubMed1994

The regulation of intestinal hypersensitivity reactions to ovalbumin by omega-3 fatty acid enriched diet: studies of IEL and LPL in mucosal damage.

In order to clarify the mechanisms of food-sensitive enteropathy, a food hypersensitive model was generated by feeding ovalbumin to female BALB/c mice after intraperitoneal injection of cyclophosphamide and morphological and immunological changes in the gut mucosa were investigated. Villus atrophy, crypt hyperplasia and increased numbers of intra-epithelial lymphocytes (IEL) were confirmed in this model, as seen in food-sensitive enteropathy in humans. Subpopulations of IEL and lamina propria lymphocytes were enumerated by immunohistochemical observation. CD8-positive cells were increased both in epithelium and lamina propria, whereas CD4-positive cells were decreased in lamina propria. We document here that orally administered food antigen actually induces food-sensitive enteropathy and mucosal damage is generated by lymphocytes that infiltrate the intestinal mucosa. We also investigated the effect of feeding an omega-3 fatty acid-enriched diet in this model and found that it was efficient in attenuating mucosal damage.

Animals↗
PubMed1994

[Serodiagnosis of Legionella pneumonia--data of our laboratory in the recent 3 years].

We had examined antibody titers against Legionella spp. of patients' sera which were mainly sent from other hospitals, performed with the indirect fluorescent antibody (IFA) method. The clinical status of the cases diagnosed as Legionella pneumonia serologically, were also studied. Out of 105 cases with clinically suspected Legionella pneumonia, 15 cases (14.3%) were seropositive. In 9 out of the 15 cases (60.0%) were caused by Legionella pneumophila serogroup 1. Clinical outline of these 15 cases did not contradict those reported in the literature, and erythromycin was effective in many cases. Significant rises (more than four times) of the titer were observed 3 to 4 weeks after onset in most of cases. We would like to emphasize that this should be performed serodiagnosis of Legionella pneumonia.

Adult↗
PubMed1994

Pyridonecarboxylic acids as antibacterial agents. VII. Synthesis and structure-activity relationship of amino- and hydroxyl-substituted 7-cycloalkyl and 7-vinyl derivatives of 1-cyclopropyl-6-fluoro-4-quinolone-3- carboxylic acid.

Novel C(7)-derivatives of 1-cyclopropyl-6-fluoro-4-quinolone carboxylic acid (3a-o) have been synthesized and evaluated for in vitro antibacterial activity. Compounds 3e (3-aminocyclobutyl), 3g (1-aminocyclopropyl), 3m ((2-aminomethyl)vinyl), and 3o ((1-aminomethyl)vinyl) showed significant inhibitory activity, comparable to that of ciprofloxacin, against gram-negative bacteria including P. aeruginosa. A good pharmacokinetic profile (serum and brain concentrations and urinary recovery) was obtained for the two cyclic compounds (3e and 3g), but that of the vinylic compounds (3m and 3o) was less favorable. Compound 3g was less toxic than 3e, ciprofloxacin, or ofloxacin in terms of acute toxicity and convulsion-induction.

4-Quinolones↗
PubMed1994

Pyridonecarboxylic acids as antibacterial agents. VIII. Synthesis and structure-activity relationship of 7-(1-aminocyclopropyl)-4-oxo-1,8-naphthyridine-3-carboxylic acids and 7-(1-aminocyclopropyl)-4-oxoquinoline-3-carboxylic acids.

4-Oxo-1,8-naphthyridine- and 4-oxoquinoline-3-carboxylic acids (2a, b and 3a-1) possessing a 1-amino-cyclopropyl group at the 7-position have been synthesized and evaluated for in vitro antibacterial activities. The three quinolones (3d, h, i) exhibited potent antibacterial activities against both gram-positive and gram-negative bacteria, which are comparable to those of ciprofloxacin (CPFX) and ofloxacin (OFLX). Among the three compounds, the best pharmacological and pharmacokinetic profile was obtained with 3i, an OFLX analogue, which was considerably less toxic than three reference quinolones (1, CPFX and OFLX).

4-Quinolones↗
PubMed1994

Amino acids and peptides. XXI. Laminin-related peptide analogs including poly(ethylene glycol) hybrids and their inhibitory effect on experimental metastasis.

Laminin-related peptides, Tyr-Ile-Gly-Ser-Arg analogs, were prepared and their inhibitory effects on experimental metastasis were examined. Of the amino acids in the Tyr-Ile-Gly-Ser-Arg sequence, L-Arg was very important and Ile was not essential for the inhibitory effect. To obtain a potent inhibitor of metastasis, hybrids of Tyr-Ile-Gly-Ser-Arg-Gly and 2 types of poly(ethylene glycol) were prepared. The inhibitory effects of the hybrids were more potent than that of Tyr-Ile-Gly-Ser-Arg-Gly.

Amino Acid Sequence↗