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Biomedical subjects

H Okazaki

Publications and source records attributed to H Okazaki.

At least 379 records · Page 21Linked to original sources
PubMed1980

Vertebral-basilar distribution infarction following chiropractic cervical manipulation.

Previous case reports of vertebral-basilar system infarction following chiropractic cervical manipulation have emphasized the role of predisposing factors such as cervical spondylosis, atherosclerosis, and congenital asymmetry of the posterior circulation. Ten patients without prior neurologic symptoms had vertebral-basilar system infarction promptly after chiropractic maneuvers. One patient, who was free of clinical and radiographic evidence of predisposing factors, subsequently died. Autopsy studies revealed massive nonhemorrhagic brainstem infarction due to bilateral vertebral artery thrombosis. Nine patients survived with residual neurologic deficits due to lesions in various locations of the posterior circulation. No patient received anticoagulants. Previous case reports are summarized and the kinetic anatomy of the vertebral arteries is reviewed to clarify the potential mechanisms involved in the pathogenesis of this entity. Although a causal relationship may be difficult to establish in individual cases, cervical manipulation seems to be the major identifiable factor in the pathogenesis of stroke in some patients.

Adolescent↗
PubMed1979

Multiple endocrine neoplasia, type 2b: phenotype recognition; neurological features and their pathological basis.

Sixteen patients affected with multiple endocrine neoplasia, type 2b (MEN 2b), were evaluated by clinical, neurological, nerve conduction and electromyographic, and postmortem examinations. Eight of the 11 patients examined clinically had symptoms: 5, neurogenic constipation; 1, failing vision due to hypertrophied corneal nerves; 1, neuromuscular symptoms and pes cavus; and 1, facial disfigurement. Expression of the dominantly inherited MEN 2b gene is more variable than previously known. When neuromuscular findings are present alone, the features may be those of peroneal muscular atrophy. Because 10 of the 11 patients had sufficiently full expression of the dominantly inherited gene--"Marfanlike" body build, full and fleshy lips, whitish yellow nodules (neuromas) on the tip and edges of the tongue, pes cavus, or peroneal muscular atrophy--the presence of MEN 2b was recognized and a search for the usually associated medullary thyroid carcinoma was instigated. In addition to the recognized involvement of autonomic nerves, we have confirmed that somatic motor and senory neurons may be involved. Findings at postmortem evaluation indicate that symptoms can be attributed to neuroma formation: a characteristic adventitious plaque of tissue composed of hyperplastic, interlacing bands of Schwann cells and myelinated fibers overlay the posterior columns of the spinal cord.

Adolescent↗
PubMed1979

Neurofibrillary degeneration on Guam: frequency in Chamorros and non Chamorros with no known neurological disease.

In a neuropathological study of the brains of 69 members of the Guamanian Chamorro population without known evidence of dementia, parkinsonism or amyotrophic lateral sclerosis, the incidence and severity of neurofibrillary degeneration was determined in relation to age at death. It was found that neurofibrillary degeneration is present at an earlier age than has been reported for a comparable population in Japan, and much earlier than reported for two similarly comparable English populations. Our data suggests that neurofibrillary degeneration is the common denominator of the Guam neurological syndromes of parkinsonian dementia, amyotrophic lateral sclerosis and dementia without parkinsonism. This conclusion would imply that the aetiological factor of neurofibrillary degeneration is more widely dispersed in the population than suggested by the cases of parkinsonian dementia and amyotrophic lateral sclerosis alone. Both sexes were equally affected while clinical parkinsonian dementia is three times more frequent among males. The sample data suggests a positive association with the amyotrophic lateral sclerosis-parkinsonian dementia rate in village of birth and residence, and also with family history; the results in the small subsamples are not significant. Senile plaques were found in few control cases in this study, just as there has been a relative absence of senile plaques in cases of parkinsonian dementia. In a small group of Caucasians who had spent many of their adult years on Guam, the frequency of neurofibrillary degeneration in relationship to age was comparable to that in the English populations.

Adolescent↗
PubMed1979

Properties of purified calf thymus poly(adenosine diphosphate ribose) polymerase. Comparison of the DNA-independent and the DNA-dependent enzyme.

The physicochemical properties of the purified calf thymus poly(ADP-ribose) polymerase were investigated. The enzyme purified to homogeneity was shown to contain about 10% DNA on a weight basis and its activity to be DNA independent. After removing this fragment of DNA, called the sDNA fraction, the enzyme becomes DNA dependent. The activity of this enzyme preparation was entirely dependent on, and completely restored by, added calf thymus DNA or sDNA. However, the calf thymus DNA concentration needed was a hundred times higher than that of sDNA. The properties of the two enzyme preparations, DNA independent and DNA dependent, were essentially the same. They both reacted against the specific antibody obtained with the DNA-independent poly(ADP-ribose) polymerase. The pH optimum was around 8; the activity was stimulated by Mg2+, Mn2+ and Ca2+, and inhibited by high ionic strength, p-chloromercuribenzoate, ADP-ribose, AMP and polylysine. Nicotinamide, thymidine and NADP were shown to be competitive inhibitors. The enzymatic activity was stimulated by histone H1 when the ratio of DNA to histone H1 was 2. Histones H2A, H2B, H3 and H4 had little effect on the DNA-independent enzyme activity, but were strongly inhibitory for the DNA-dependent enzyme. This inhibitory effect could be reversed by allowing the DNA-dependent enzyme to react with the sDNA fraction before adding histone subfractions. The apparent Km for NAD of the DNA-dependent poly(ADP-ribose) polymerase was shown to vary with the DNA concentration. It was minimum when the amount of sDNA was 10% of that of the enzyme. The ratio of the apparent Km for sDNA to the enzyme concentration was constant at any enzyme concentration. The minimum estimation of the number of base pairs of sDNA required for maximal activation of one enzyme molecule was 16. For calf thymus DNA, this estimation was of 640. These results suggest that the activation of the enzyme needs the formation of some complex between the protein and a specific part of the DNA. This complex was preserved in the DNA-independent enzyme preparation.

Animals↗