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N Tamiya

Publications and source records attributed to N Tamiya.

119 records · Page 7Linked to original sources
PubMed1969

Properties and biosynthesis of a neurotoxic protein of the venoms of s snakes Laticauda laticaudata and Laticauda colubrina.

1. A neurotoxic protein similar to erabutoxins a and b of Laticauda semifasciata was isolated in crystalline form from the venoms of Laticauda laticaudata and Laticauda colubrina. The name ;laticotoxin a' is proposed. 2. Laticotoxin a is homogeneous by CM-cellulose column chromatography, disc electrophoresis and ultracentrifugation and by terminal amino acid analyses. 3. Laticotoxin a consists of 62 amino acid residues. The molecular weight by ultracentrifuging is 6520. 4. The minimal 50% lethal dose of laticotoxin a by intramuscular injection to mice is 0.13mug./g. body wt. The toxin attacks the postsynaptic membrane, competing with acetylcholine. 5. Radioactive amino acids are incorporated into laticotoxin a in vivo. The incorporation is inhibited by puromycin, suggesting that the biosynthesis of the toxin follows the mechanism of protein biosynthesis, although the toxin molecule is rather small as a protein.

Acetylcholine↗
PubMed1969

The enzymic hydroxylation of protocollagen models.

1. Synthetic polymers of l-prolyl-l-prolylglycine of defined chain length, (Pro-Pro-Gly)(n), were found to be substrates for the enzyme protocollagen-proline hydroxylase, with optimum chain length n=5. Boiling the polymer (Pro-Pro-Gly)(15) increased its activity as a substrate but had no effect on (Pro-Pro-Gly)(5). 2. Protection of both or one of the N- and C-terminal groups made (Pro-Pro-Gly)(3) a better substrate, and collagenase digestion of hydroxylated tert.-pentyloxy-carbonyl-(Pro-Pro-Gly)(3) benzyl ester indicated that the central prolyl residues were the major points of hydroxylation. 3. The results suggest that the long-chain peptides are optimum substrates but that a triple-stranded structure is inhibitory for hydroxylation.

Animals↗
PubMed1966

Studies on sea-snake venoms. Crystallization of erabutoxins a and b from Laticauda semifasciata venom.

1. The toxic principles in the venom of the sea-snake Laticauda semifasciata were separated into two components by CM-cellulose chromatography and obtained in crystalline forms. They were named ;erabutoxins a and b'. 2. The homogeneity of each toxin was shown by rechromatography, by disk electrophoresis, by ultracentrifuging, by toxicity measurements before and after repeated crystallizations and by N-terminal analysis. 3. They had molecular weights of about 7000. Both of them contained 61 (or 62) amino acid residues/molecule. The only difference between erabutoxins a and b was that one of the aspartic acid (or asparagine) residues in erabutoxin a was replaced by a histidine residue in erabutoxin b. 4. Both of the toxins had LD(50) values of 0.15mug./g. body wt. for mice and 0.07mug./g. for rats. It was shown with frog-muscle preparations that they acted on postsynaptic membrane to block neuromuscular transmission.

Amino Acids↗
PubMedDate not supplied

Factors related to home discharge of cerebrovascular disease patients: 1-year follow-up interview survey of caregivers of hospitalized patients in 53 acute care hospitals in Japan.

In Japan, many disabled elderly people remain hospitalized for long periods. Cerebrovascular diseases (CVD) are the most causes responsible for such disability. To examine the predictors of home discharge in CVD patients, we performed a 1-year follow-up interview of the main caregivers of patients hospitalized with a CVD event. The initial cohort consisted of CVD patients hospitalized in all the second level emergency and general hospitals in Ibaraki Prefecture in February 1992 (N=888 patients in 53 hospitals). In the following year, we performed an interview survey of the main caregivers of these CVD patients. The survey items included the characteristics of the patients (including medical and socioeconomic conditions), caregivers, and family members. The final study population included the main caregivers of 187 home patients and 90 institutionalized patients. We compared these two groups in terms of predictors of discharge to home. The results of multiple logistic regression analysis showed that the following seven factors were related to home discharge; better baseline activities of daily living (ADL), larger improvement in ADL, larger family size, spouse as the caregiver, caregiver without a full-time job, better economic status of the caregiver, and sources of the patient's income. Our study indicated that the caregiver's conditions were closely related to home discharge of the CVD patients. More attention should, therefore, be centered on the caregiver's well-being and economic aspects as well as the patient's conditions in order to encourage home discharge of stroke patients.

Journal Article↗