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Biomedical subjects

A Yamazaki

Publications and source records attributed to A Yamazaki.

At least 181 records · Page 10Linked to original sources
PubMed1979

Anomalous systemic arterial supply to the basal segments of the lung presenting with a murmur.

A murmur was discovered on routine preschool physical examination of a 5 year and 7 month-old boy. A lower lobe lesion was detected by chest X-ray. Aortography demonstrated that a large systemic artery from the descending thoracic aorta supplied the basilar segments of the left lower lobe, which had no normal pulmonary arterial supply. A clinical diagnosis of intralobar sequestration of the lung was made, and left lower lobectomy was performed.

Aorta, Thoracic↗
PubMed1979

Rebound nystagmus: EOG analysis of a case with a floccular tumour.

Eye movements were recorded and quantitatively analysed in a patient with a tumour initially involving the cerebellar flocculus. Ocular motor abnormalities included (1) impaired smooth pursuit, (2) impaired cancellation of the vestibulo-ocular reflex when fixating an object rotating with the head, and (3) gaze paretic and rebound nystagmus. Comparable findings have been reported in monkeys with experimental floccular lesions. The rebound nystagmus (but not the other ocular motor abnormalities) disappeared when the tumour appeared to invade the brain stem in the region near the vestibular nuclei. This finding suggests that the floccular lesion unmasked a bias which created rebound nystagmus and that the bias probably arose in the vestibular nuclei.

Adolescent↗
PubMed1976

A new synthesis of inosine from 5-amino-1-beta-D-ribofuranosyl-4-imidazole-carboxamide.

Inosine was prepared (15% yield) by treatment of 5-amino-1-beta-D-ribofuranosyl-4-imidazolecarboxamide (AICA-riboside) with chloroform in the presence of sodium methoxide. This ring closure can be reasonably explained by assuming the formation of dichlorocarbene from chloroform and alkali. Carbon tetrachloride or hexachloroethane as a carbene source was more effective for the ring closure of AICA-riboside, giving inosine in 48% and 51% yields respectively.

Cyclization↗
PubMed1976

Synthesis of guanosine and its derivatives from 5-amino-1-beta-D-ribofuranosyl-4-imidazolecarboxamide. III. Formation of a novel cycloimidazole nucleoside and its cleavage reactions.

A new cycloimidazole nucleoside, 5-(1 inch -benzamido-1 inch-hydroxymethylene) amino-2', 1 inch-anhydro-1-beta-D-ribofuranosyl-4-imidazolecarboxamide (III) was synthesized by reaction of 5-amino-1-beta-D-ribofuranosyl-4-imidazolecarboxamide (AICA-riboside) with benzoyl isothiocyanate followed by methylation with methyl iodide. The structure of III was elucidated on the basis of its nmr spectra and chemical reactions. Of special interest are reactions of III with various nucleophiles. For example, guanosine (IX) was obtained by amination of III wtih ammonia in 72% yield. Analogous reactions of III with methylamine and dimethylamine gave N2-methylguanosine (X) and N2-dimethylguanosine (XI), respectively. Refluxing of III in alkaline solution afforded xanthosine (VII). The probable mechanism of formation and facile ring-opening of III is also discussed.

Guanosine↗
PubMed1976

Synthesis of guanosine and its derivatives from 5-amino-1-beta-D-ribofuranosyl-e-imidazolecarboxamide. IV. A new route to guanosine via cyanamide derivative.

4-Cyanamido-5-imidazolecarboxamide (IV) was prepared by brief treatment of 5-(S-methylisothiocarbamoyl) amino-4-imidazolecarboxamide (V) with alkali. Compound VI was converted in an alkaline solution to either guanine (VII) or isoguanine (VIII), depending on the concentration of alkali. This procedure was applied to the synthesis of 2',3'-0-isopropylideneguanosine (XVI) from the riboside of 5-(N'-benzoyl-S-methylthiocarbamoyl) amino-4-imidazolecarboxamide (IX), PROviding a new route to XVI.

Guanosine↗