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Biomedical subjects

T Tokunaga

Publications and source records attributed to T Tokunaga.

At least 289 records · Page 16Linked to original sources
PubMed1981

Total synthesis of a RNA molecule with sequence identical to that of Escherichia coli formylmethionine tRNA.

A RNA molecule has been synthesized that is identical in sequence to Escherichia coli tRNAfMet except that it lacks the base modifications present in the E. coli tRNA. This was achieved by enzymatic joining of chemically synthesized oligonucleotides with chain lengths of 3-10 which were synthesized by the phosphodiester or phosphotriester method. First, quarter molecules of tRNA were constructed by joining of chemically synthesized fragments with RNA ligase. The 5'-quarter molecule (bases 1-20) served as an acceptor in joining reactions with the 3',5'-bisphosphorylated donor molecule (bases 21-34). The 5'-half molecule thus obtained was treated with phosphatase and joined to the 3'-half molecule which was prepared by ligation of the other quarter molecules (bases 35-60, acceptor; bases 61-77, donor) followed by 5'-phosphorylation with polynucleotide kinase. The synthetic tRNA was characterized by oligonucleotide pattern and was partially active in aminoacylation with E. coli methionyl-tRNA synthetase.

Base Sequence↗
PubMed1981

Suppression of delayed hypersensitivity by measles virus infection in guinea pigs.

A guinea pig model of mild measles virus infection was established by the intranasal inoculation with Toyoshima strain. The infection was confirmed by the development of both humoral and cell-mediated immunities to measles virus as well as by the demonstration of transient virus growth in the lymphoid tissues. The virus infection caused a transient suppression of delayed hypersensitivity to purified protein derivative (PPD) at both the induction and expression phases, whereas Jones-Mote-type hypersensitivity to ovalbumin developed in a normal fashion. In the virus-infected animals, the suppressed response to the skin reacting factor was observed as well, however in vitro responsiveness of lymphocytes to PPD was not suppressed. On the other hand, transient enhancement of skin reactivity to phytohemagglutinin by virus infection was noticed. These results may indicate subtle alterations of immune functions in guinea pigs during measles virus infection.

Animals↗
PubMed1980

[A case of 17 alpha-hydroxylase deficiency with male pseudohermaphroditism (author's transl)].

A 17-year-old youth was admitted because of proteinuria noted during a routine examination at his high school. His parents and three siblings were living in good health and there was no familial tendency to hypertension and no consanguinity. On physical examination, he was 161cm in height and weighed 43Kg, and his facial expression was female-like. Neither webbed neck nor cubitus valgus was noticed. Severe hypertension ranging from 190/120 to 230/130 was noted. No axillary or pubic hair was present, and the breasts were prepubertal in size. A gynecological examination revealed the presence of labia and vagina. Laboratory findings on admission were summarized as follows: The urine gave a (-)--(+) test for protein, renal function was revealed as normal, serum potassium ranged from 3.2 to 4.2mEq/L, the specimen of arterial blood showed pH 7.421, and an electrocardiogram revealed left ventricular hypertrophy and U wave changes in leads V2, V3, V4. X-rays showed a bone age of 12 years, and chromosome analysis revealed a karyo type of 46,XY. Endocrinological studies confirming the presence of a 17 alpha-hydroxylase deficiency were summarized as follows: 1) Plasma ACTH was markedly elevated. 2) Plasma renin activity was markedly suppressed showing no response to exercise. 3) Plasma progesteron, plasma DOC and plasma-corticosteron were extremely high. In contrast, plasma aldosteron was extremely low. 4) Plasma 17 alpha-OH progesteron and plasma cortisol were markedly reduced. Urinary excretion of 17-OHCS was extremely low. 5) Plasma testosteron and urinary 17-KS were markedly reduced. The patient was treated with 2mg then 1mg dexamethasone daily for half a year. After one month of therapy, the blood pressure was down to 160/100mmHg, and the serum potassium had risen from 3.2mEq/liter to 5.6mEq/liter. Plasma progesteron, plasma DOC, plasma corticosteron and plasma ACTH decreased to a normal level. Subsequently suppressed plasma renin activity elevated to a normal value. After 6 weeks of this treatment, a laparotomy was performed. Ovaries and uterus were absent, but bilateral testes were found at the external inguinal ring. Microscopic examination of the testis showed Sertoli cell adenoma. We have reported here a case of 17 alpha-hydroxylase deficiency with male pseudohermaphoriditism and discussed the endocrinological data and histological findings of the testis.

Adolescent↗
PubMed1980

Induction of suppressor T cells in delayed-type hypersensitivity to Mycobacterium bovis BCG in low-responder mice.

The induction of delayed-type hypersensitivity to Mycobacterium bovis BCG was specifically inhibited by suppressor T cells in C3H/He, a strain of mice which is a low responder to BCG. The existence of these suppressor cells was confirmed by an adoptive transfer of spleen cells of BCG-injected mice into cyclophosphamide-treated recipients. The suppressor cells appeared in the spleens of the mice 2 to 7 days after intravenous BCG injection. They were sensitive to anti-theta serum and complement and did not adhere to Sephadex G-10. A pretreatment of the mice with cyclophosphamide eliminated the suppression of delayed-type hypersensitivity. These suppressor cells effectively inhibited the induction of delayed-type hypersensitivity to BCG, but showed only weak effect on the expression of it.

Animals↗