Biomedical subjects

T Asami

Publications and source records attributed to T Asami.

At least 73 records · Page 4Linked to original sources

PubMed1995

Effects of L-thyroxine on serum lipid profiles in infants with congenital hypothyroidism.

Serum lipid profiles and the effects of thyroid hormone on them were studied in infants with congenital hypothyroidism. Serum total cholesterol, high-density lipoprotein cholesterol (HDLC), and low-density lipoprotein cholesterol levels were increased in infants with hypothyroidism;L-thyroxine therapy decreased the HDLC levels, leading to a reduction in serum concentrations of total cholesterol. It appears that thyroid hormone suppresses circulating HDLC, although the mechanism was not discovered in this study.

Congenital Hypothyroidism↗

PubMed1995

Unique form of rickets with low serum 25-hydroxyvitamin D in two normally nourished children.

We present an unusual type of rickets involving two children: a 2 year old boy and a 15 month old boy, who presented with marked bowing of the lower extremities and bulging of costochondral junctions. Both children had normal growth, with their height and body weight greater than the 50th and 97th percentile for age. Roentgenograms of their extremities showed the typical changes of vitamin D refractory rickets. Serum alkaline phosphatase levels were elevated and serum levels of calcium and phosphate were both within the normal range. No primary cause for the rickets, including nutritional deficiencies, was found in the two patients. Characteristic findings were persistently low serum 25-hydroxyvitamin D (25-OH-D) and normal 1,25-dihydroxyvitamin D (1,25-(OH)2-D). Improvements in clinical and X-ray findings were observed after either oral administration of 1 alpha-(OH)-D3 (9-15 micrograms per day) or massive vitamin D2 therapy (600,000 IU single injection). The low serum levels of 25-OH-D did not increase unless massive vitamin D2 therapy was also given. These two cases represent a unique form of rickets that does not meet the criteria for any type of previously known rickets.

25-Hydroxyvitamin D 2↗

PubMed1995

Congenital hypothyroidism with delayed rise in serum TSH missed on newborn screening.

We report on a female patient with congenital hypothyroidism (CH) missed on a newborn screening test. She is now 10 years old with retarded development. The patient was born premature at 34 weeks of gestation with birth-weight of 1515 g, and was judged to be normal in the screening programme of Niigata Prefecture. However, she gradually suffered from poor weight gain and retarded development with stridor at breathing. Serum thyroid stimulating hormone (TSH) levels were rechecked and showed high values with normal T3 and T4 levels. She was referred to our hospital at the age of 13 months. She was diagnosed as having CH (ectopic thyroid) with a delayed rise in blood TSH concentration, probably due to the prematurity of the hypothalamic-pituitary-thyroid axis. L-thyroxine therapy brought a decline in TSH levels with partial improvement of her symptoms. Regardless of the result of newborn screening, infants with elevated serum TSH levels should be carefully examined for possible CH, even when T3, T4 and free T4 values are in the normal range.

Child↗

PubMed1995

Successful alpha-interferon therapy in a child with chronic refractory idiopathic thrombocytopenic purpura: a case report.

We treated a sixteen month old male with chronic refractory idiopathic thrombocytopenic purpura (ITP) in whom alpha-interferon (IFN) therapy was effective. He developed ITP which did not respond to various treatments. Six months after admission, we began to treat him with IFN. The patient's platelet count rapidly responded to the therapy and rose above normal range. Serum levels of platelet associated immunoglobulin G (PA-IgG) showed a tendency to decrease with the administration of IFN. After stopping the IFN therapy for a duration of 3 months, the platelet count remained normal. No serious adverse side effects, except transient fever, were observed. From the experience of this case we propose that IFN is one of the therapeutic options for treatment of refractory ITP not only in adults but also in children.

Chronic Disease↗

PubMed1995

Screening for neuroblastoma: a 9-year birth cohort-based study in Niigata, Japan.

Between April 1985 and March 1994 (9 years), 229,346 babies were born in Niigata prefecture, and 201,888 (88.0%) underwent mass screening (MS) for neuroblastoma at 6 months of age. To date, 29 infants have been screen-detected as having neuroblastoma (1:7908). All screen-detected patients survived after removal of the primary tumor. In the same birth cohort, 17 additional children were clinically diagnosed as having neuroblastoma. The cumulative incidence rate of neuroblastoma at 5 years of age was 10.5 per 100,000 live births in the 5-year birth cohort before MS was introduced, and 18.6 per 100,000 in the first 5-year birth cohort after MS was introduced. These values were not statistically different. The birth cohort incidence rate increased significantly to 22.2 per 100,000 (p < 5% compared with before MS) after the method of MS was changed to high-power liquid chromatography (HPLC), even though this latest birth cohort has not been followed for 5 years. The population-based mortality rate from neuroblastoma was 5.9 per 100,000 in the 5-year birth cohort before MS, and 4.5 per 100,000 after MS in the first 5-year birth cohort, using the vanillymandelic acid (VMA) spot test. These values were not statistically significant. In contrast, no death was observed in the next 4-year birth cohort after MS using HPLC; however, this birth cohort has not yet been followed for 5 years.

Chi-Square Distribution↗

PubMed1995

Persistent non-familial asymptomatic hyperphosphatasemia: a report on three cases.

Three male children, aged 9 days, 2 years and 13 years, were found to have elevated serum alkaline phosphatase (ALP) activity (hyperphosphatasemia) in the absence of disease. In these three cases, elevation of ALP activity had persisted for 6-10 years. These patients did not inherit the disease from their parents. Isoenzyme determination revealed a skeletal origin of the elevated ALP in the three patients. They were diagnosed as having persistent non-familial asymptomatic hyperphosphatasemia (PNAH) which differs from transient and persistent asymptomatic familial hyperphosphatasemia. Reviewing the literature, although the term PNAH had not been used, two similar cases have been reported in a 24-year-old female and in a 27-year-old female. PNAH may be another type of benign hyperphosphatasemia.

Adolescent↗

PubMed1995

Inhibition of cocaine sensitization by MK-801, a noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist: evaluation by ambulatory activity in mice.

Alterations of cocaine effects, which were induced by prior repeated 5-time administration of MK-801 ((+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine) (i.p.) alone or in combination with cocaine (s.c.) at 3- to 4-day intervals, were investigated by means of ambulatory activity in mice. The repeated administration of either cocaine (10 and 20 mg/kg) alone or MK-801 (0.3 mg/kg) alone progressively enhanced each drug's effect. The enhanced effects of cocaine and MK-801 were estimated to be 1.8-2.2 times and about 1.4 times, respectively, as great as those at the 1st administration. Although the coadministration of MK-801 with cocaine produced a significant enhancement in the ambulation-increasing effect, the comparatively higher doses of MK-801 (0.3 and 1 mg/kg) acted not only to reduce cocaine sensitivity but also to inhibit the development of cocaine sensitization. Thus, the mice that had been given MK-801 (0.3 and 1 mg/kg) alone 5 times showed lower sensitivities to cocaine (20 mg/kg) than the mice given saline alone. The mice coadministered MK-801 (0.3 and 1 mg/kg) with cocaine (10 and 20 mg/kg) also exhibited lower sensitivities to cocaine (10 and 20 mg/kg) than those given cocaine alone. However, MK-801 could not ameliorate the established sensitization to cocaine. Similar interactions have been demonstrated between MK-801 at 1 mg/kg, but not 0.3 mg/kg, and methamphetamine. The present results indicate that MK-801 can inhibit the development of sensitization to cocaine at a lower dose than that required to inhibit methamphetamine sensitization.

Analysis of Variance↗

PubMed1995

New concept of spinal orthosis for weakened back muscles.

An anterior bending posture of the trunk during walking is often seen among the elderly commonly due to weakened thoraco-lumbar and gluteal muscles. For the management of this debilitating condition, the authors have developed a modified design of thoraco-lumbosacral orthosis (TLSO). Incorporated in this device are pockets for the accommodation of lead weights, which are located posteriorly at the level of the lumbar region and an elasticated anterior abdominal band. The results and level of patient acceptance achieved with the use of this brace have both been excellent.

Equipment Design↗

PubMed1995

Evaluation of acute and sub-acute effects of cocaine by means of circadian variation in wheel-running and drinking in mice.

The effects of cocaine on wheel-running and drinking activities in mice, housed under a 12-h light-dark schedule (lighted period; 6:00-18:00 h), were investigated through long continuous observation. Cocaine (20 and 40 mg/kg, sc), administered at 11:00 h, acutely increased wheel-running and drinking, but it was followed by a sub-acute suppression of the spontaneous increment in both of these behaviors during the coming dark period (18:00-6:00 h). Such behavioral accelerating and suppressing effects of cocaine did not change throughout the whole course of administration, which was repeated five times at 3- to 5-day intervals. In addition to these findings, wheel-running and drinking spontaneously increased during the light period and decreased during the dark period on the day after the drug administration. On the other hand, the repeated administration of cocaine at 18:00 h never increased, but rather acutely suppressed both behaviors during the dark period, and no trends in the behavioral changes on the next day were clearly shown. These results suggest that the effects of cocaine on wheel-running and drinking differ depending on the time of day of the administration.

Animals↗

PubMed1994

Cyclic hexapeptide endothelin receptor antagonists highly potent for both receptor subtypes ETA and ETB.

A cyclic hexapeptide, cyclo(-D-Asp-Trp-Asp-D-Leu-Leu-D-Trp-), designed from cyclo(-D-Glu-Ala-D-alloisoleucyl-Leu-D-Trp-), an ETA receptor-selective antagonist, possessed not only affinity similar to that of BQ-123 for ETA but also higher affinity for ETB than BQ-123. Further modification led to the discovery of cyclo(-D-Asp-Asp(Php)-Asp-D-Thg-Leu-D-Trp-) (Asp(Php): 1-beta-aspartyl-4-phenylpiperazine; Thg: 2-(2-thienyl)glycine) that inhibited [125I]ET-1 binding to the ETA and ETB receptors with IC50 values of 0.082 nM and 120 nM, respectively. Although this compound possesses 1470-fold less affinity for ETB than for ETA, it behaves as a non-selective antagonist that equipotently inhibits vasoconstriction mediated by both receptor subtypes ETA and ETB.

Amino Acid Sequence↗

PubMed1994

Correlation between inflammatory cellular responses and chemotactic activity in bronchoalveolar lavage fluid following intratracheal instillation of nickel sulfate in rats.

In a preceding study, we reported that the numbers of macrophages and polymorphonuclear leukocytes (PMN) were increased in bronchoalveolar lavage fluid (BALF) following the intratracheal instillation of nickel sulfate (NiSO4) in rats. In the present study, BALF chemotactic activities for both macrophages and PMN were measured to investigate if the increases of these inflammatory cells in BALF depend on increases in chemotactic activities in epithelial lining fluid (ELF) of the lung. Both the number of PMN and the PMN chemotactic activity peaked at 2 days post-instillation and they were significantly correlated. However, the PMN chemotactic activity was inversely correlated with concentration of leukotriene B4 (LTB4), a well-known chemotaxin. Although PMN were not observed in control BALF, LTB4 concentration in the control ELF (ca. 5 x 10(-7) M) was estimated to have a potential to attract PMN chemotactically through a membrane in in vitro migration assay. These results suggest that the presence of LTB4 in ELF itself does not trigger transpulmonary PMN infiltration. The rat BALF were fractionated by high performance liquid chromatography (HPLC), and PMN chemotactic activity of each fraction was measured. The elution profiles of PMN chemotactic activity showed that there were at least two different chemotaxins in BALF obtained from the NiSO4-exposed rats. Macrophage chemotactic activity in BALF also peaked at 2 days post-instillation. However, the number of macrophages was not significantly correlated with the chemotactic activity for macrophage in BALF.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1993

Endothelin-1 analogues substituted at both position 18 and 19: highly potent endothelin antagonists with no selectivity for either receptor subtype ETA or ETB.

Novel endothelin-1 (ET-1) analogues which are highly potent endothelin antagonists at both receptor subtype ETA and ETB are reported. The replacement of Asp18 with the Thr18 and of Ile19 with a hydrophobic amino acid whose side-chain branches on the gamma-carbon such as Leu, cyclohexylalanine, and gamma-methylleucine (gamma-MeLeu) resulted in loss of or significantly decreased the biological activity of ET-1, while high affinity for the ETA (IC50 = 0.42-0.70 nM) and ETB (IC50 = 0.17-0.43 nM) receptor was retained. These compounds were shown to have high antagonist activities in ET-1-induced vasoconstriction of porcine coronary artery (pA2 7.4-7.7) and in Sarafotoxin S6c-induced vasoconstriction of rabbit pulmonary artery ([Thr18, gamma-MeLeu19]ET-1: pA2 8.4). Among these compounds, [Thr18, gamma-MeLeu19]ET-1 has the desirable characteristic of possessing no agonist activity at either receptor subtype.

Amino Acid Sequence↗

PubMed1993

Design and synthesis of ETA receptor antagonists and study of ETA receptor distribution.

Many oligopeptides were designed to find ETA receptor antagonists on the hypothesis that an ETA receptor can recognize two hydrophobic parts of ET-1, i.e., Val-Tyr-Phe and Ile-Ile-Trp, over a short distance. They were synthesized from the benzyl ester of the C-terminal amino acid by stepwise chain elongation using the solution method. The binding affinity of the synthetic peptides to the endothelin receptors was examined in porcine cardiac ventricular muscle membrane for ETA receptor and in bovine whole brain membrane for ETB receptor. Hexamethyleneiminocarbonyl-Leu-trp-ala-beta ala-tyr-phe (TTA-386) was selected as an ETA receptor-selective competitive antagonist to ET-1. It competed against ET-1 at ETA receptor sites and showed one-third the binding affinity of ET-1 for ETA receptor and < 1/10,000 the affinity for ETB receptor. It inhibited the ET-1-induced increase of cytosolic free calcium concentration in A-10 cells. The 125I-labeled hexapeptide (125I-TTA-386) was prepared to distinguish the distribution of ETA receptor from ETB receptor. Scatchard plot analysis of saturation binding of 125I-TTA-386 to porcine cardiac membranes showed the same Bmax value as that of 125I-ET-1. Autoradiographic studies showed that ETA receptors are most abundant in the cardiac muscle, intestine, large bowel, spleen, and testis.

Amino Acid Sequence↗

PubMed1993

Elevated serum fucose levels in idiopathic nephrotic syndrome.

We measured serum fucose concentrations in 34 children with idiopathic nephrotic syndrome (INS), 23 with chance proteinuria and/or hematuria (CPH), and 20 healthy children as controls. The serum fucose levels in the patients with INS were significantly elevated at onset (14.0 +/- 3.7 mg/dl, n = 4, p < 0.02), in relapses (19.1 +/- 3.7 mg/dl, n = 10, p < 0.001), and in remission (13.9 +/- 7.0 mg/dl, n = 30, p < 0.01) as compared with CPH patients (10.6 +/- 3.2 mg/dl, n = 23) and controls (9.1 +/- 3.1 mg/dl, n = 20). Those in remission were further divided into 2 groups and the mean fucose concentrations were significantly different in the two remission groups: 20.1 +/- 4.6 mg/dl in 14 patients whose blood samples were taken within one week of remission and 9.0 +/- 2.9 mg/dl in the other 16 patients whose samples were taken at 1 to 6 months of remission. The mean value in the latter remission group was significantly lower in comparison with the former group, but not different from the controls. Gel-chromatography of serum samples from patients with INS revealed a single peak of fucose in the high molecular fraction, and this was also found in the same fractions of serum inhibitor of lymphocyte blastogenesis in INS. We concluded that serum fucose concentrations are elevated in INS patients and that, because of the large molecular weight, the fucose is probably in a form bounded to some glycoproteins in the serum. Considering various reports on fucose, serum fucose may be associated with immunodepression in INS patients.

Child↗

PubMed1992

Effects of repeated MK-801 on ambulation in mice and in sensitization following methamphetamine.

The noncompetitive NMDA receptor antagonist MK-801, (+)-5-methyl-10,11-dihydro-5H-dibenzo-[a,d]-cyclohepten-5,10-imine , increased ambulatory activity in the mouse at doses over 0.1 mg/kg (IP). The effect was enhanced when 0.3 mg/kg MK-801 was repeatedly administered at intervals of 3-4 days. In contrast, a reduction of the effect was induced with repeated doses of 0.1 and 1 mg/kg. The mice that had repeatedly experienced 1 mg/kg MK-801 exhibited a decrease in the sensitivity to methamphetamine (2 mg/kg SC). In addition, the repeated co-administration of 1 mg/kg MK-801 with methamphetamine induced a decrease in the sensitivity to methamphetamine. No modification of methamphetamine sensitivity was elicited by 0.1 and 0.3 mg/kg MK-801 in both the single and co-administration schedules. On the other hand, established sensitization to methamphetamine was hardly affected by repeated treatment with 0.1-1 mg/kg MK-801. These results indicate that the mechanism of the inhibitory action of MK-801 on the development of methamphetamine sensitization is different from that of dopamine D2 antagonists, which may act to decrease the effective unit dose of methamphetamine and reduce ambulation-increasing effect of methamphetamine.

Animals↗

PubMed1992

Circadian variation in R-THBP-induced enhancement of the ambulation-increasing effect of methamphetamine on mice.

6R-L-erythro-5,6,7,8-tetrahydrobiopterin (R-THBP), a co-factor for tyrosine hydroxylase and tryptophan hydroxylase, induces the enhancement of ambulation-increasing effect of methamphetamine on mice. In this study, we investigated the circadian variation in the interaction between R-THBP and methamphetamine by changing the time-of-day of both methamphetamine administration and pretreatment with R-THBP. The mouse's ambulatory activity was measured by a tilting-type activity cage for 4 hr. In the daytime, but not in the nighttime, the ambulation-increasing effect of methamphetamine (1 and 2 mg/kg, s.c.) was significantly enhanced by the pretreatment with R-THBP (100 mg/kg, s.c., 2 or 6 hr before). These data indicate the possibility that peripherally administered R-THBP increases the biosynthesis of catecholamine especially in the daytime.

Analysis of Variance↗

PubMed1992

Heat treatment of Japanese lacquerware renders it hypoallergenic.

Japanese lacquer is made from the sap of the Japanese lacquer tree (Toxicodendron vernicifluum), a member of the Anacardiacae plant family. Objects painted with this material are described collectively as lacquerware. Both fresh lacquer and lacquerware may evoke allergic contact reactions ascribable to the urushiols contained therein. In this study, we have examined the effects of heating on the ability of lacquerware to elicit an allergic contact reaction. Lacquer films prepared with and without heat treatment were tested on urushiol-sensitive subjects. Patch test reactions were strongest to untreated film and decreased with increasing level of heat treatment. Assays for free urushiol in the lacquer films demonstrated that free urushiol content decreased with increasing heat treatment and that urushiols with saturated and monounsaturated alk(en)yl chains predominated.

Adult↗

PubMed1992

Genetic relatedness of Bradyrhizobium japonicum field isolates as revealed by repeated sequences and various other characteristics.

Forty-nine isolates of Bradyrhizobium japonicum indigenous to a field where soybeans were grown for 45 years without inoculation were characterized by using four DNA hybridization probes from B. japonicum. nifDK-specific hybridization clearly divided the isolates into two divergent groups. Diversity in repeated-sequence (RS)-specific hybridization was observed; 44 isolates derived from 41 nodules were divided into 33 different RS fingerprint groups. Cluster analysis showed that the RS fingerprints were correlated with the nif and hup genotypes. We found multiple bands of RS-specific hybridization for two isolates that differed from the patterns of the other isolates. These results suggest that RS fingerprinting is a valuable tool for evaluating the genetic structure of indigenous B. japonicum populations.

Bacterial Typing Techniques↗