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Biomedical subjects

H Okazaki

Publications and source records attributed to H Okazaki.

At least 415 records · Page 23Linked to original sources
PubMed1977

Splanchnic preganglionic neurons in man. I. Morphometry of preganglionic cytons.

The thoracic sympathetic preganglionic outflow is important in the maintenance of postural normotension in man. Normative data on the intermediolateral column (ILC) neuron cell bodies is lacking. Counts and measurements on the right ILC cytons have been performed on the T6, T7 and T8 segments of 12 spinal cords of man obtained within 4-6 h of death. A methodology was employed which has been optimized to prevent shrinkage of cytoplasm from the neuropil and which mathematically corrects the number of cytons of neurons and their frequency distribution for split cell error. The mean cyton counts for T6, T7 and T8 spinal cord segments were 5002, 5004 and 4654 respectively. No significant sex difference was shown. Most cytons ranged in diameter from 8-23 micrometer; the major peak in the size histogram is at 12-13 micrometer and a smaller peak is seen at 16 micrometer. There is a progressive reduction of ILC cytons with age. In adult man approximately 370 cytons (approximately 8%) are lost per decade. This reduction in ILC cytons with age may be a morphological basis for postural hypotension of the aged.

Adult↗
PubMed1977

Computerized tomography in demyelinating disease of the young.

We have used computerized tomography (CT) to look for evidence of cerebral demyelination in children with progressive neurologic disorders. Fourteen patients with a clinical diagnosis of a demyelinating disorder were examined by CT, and five had CT findings suggesting cerebral demyelination. In two patients with a so-called myelinoclastic demyelinating disease, CT showed asymmetric, circumscribed areas of diminished radiodensity, and in three patients with a leukodystrophy, scans showed diffuse symmetric areas of low density in the centrum ovale. Autopsy examination in one patient confirmed the diagnosis of sudanophilic leukodystrophy and substantiated the abnormalities suspected from CT.

Adolescent↗
PubMed1976

Morphometry of myelinated fibers of fasciculus gracilis of man.

The number of myelinated fibers per square millimeter of fasciculus gracilis, and of large and small myelinated fibers per square millimeter of fasciculus gracilis, at the C3 and T5 segements of spinal cord from 22 persons of different ages have been estimated, with a 95% confidence limit, assisted by semi-automatic methods of measurement and using programmed calculation and plotting. In addition, the histograms for diameter of myelinated fibers and mean diameter were obtained. At C3, the numbers of myelinated fibers ranged from 19,647/mm2 to 35,773/mm2, with a mean of 25,267/mm2. The number is less with older age. At T5, numbers of myelinated fibers ranged from 17,804/mm2 to 29,486/mm2, with a mean of 23,069/mm2. The number of myelinated fibers was greater at C3 than at T5 in subjects under 45. The mean diameter of myelinated fibers at C3 was smaller than that at T5. The normative data presented here should be useful for comparing with similarly derived data from patients with diseases of peripheral nerves, in evaluating the three-dimensional morphologic alteration of primary afferent neurons.

Adolescent↗
PubMed1976

A transmissible subacute spongiform encephalopathy in a visitor to the eastern highlands of New Guinea.

A Caucasian male, clinically ill with a respiratory disease, visited the Eastern Highlands of New Guinea (endemic for kuru in the Fore people) and developed subacute spongiform encephalopathy (Jakob-Creutzfeldt disease) ten weeks later, from which he subsequently died. Brain material was inoculated intracranially into squirrel monkeys, and several of them developed a spongiform encephalopathy. Monkeys that received control material (normal brain) were normal. Electronmicroscopic features in affected brain tissue are described, and the question of a relationship between Jakob-Creutzfeldt disease and kuru is considered.

Animals↗
PubMed1976

Radioimmunoassay of sisomicin.

An antibody induced in rabbits against a gentamicin-bovine serum albumin conjugate cross-reacted with the chemically related aminoglycoside, sisomicin, facilitating the development of a sisomicin radioimmunoassay. Sisomicin was labeled with (125)I using an acylating agent [3-(4-hydroxyphenyl)propionic acid-N-hydroxy-succinimide ester]. The resulting assay produced a linear standard curve on a logit-log plot with a sensitivity of 140 pg. Comparison with a microbiological assay showed no significant difference (P < 0.001) in the measurement of sisomicin by these two methods.

Animals↗
PubMed1975

Purification of an alkaline ribonuclease from soluble fraction of beef brain.

A ribonuclease (ribonucleate 3-pyrimidine-oligonucleotidohydrolase, EC 3.1.4.22) was purified 8300-fold from soluble fraction of beef brain and its properties were investigated. The enzyme is an endonuclease capable of hydrolyzing tRNA, rRNA, poly(C), but shows no activity towards poly(U), poly(A), and poly(G). The preparation is free of deoxyribonuclease, non-specific phosphodiesterase and phosphomonoesterase activity. The enzyme has a pH optimum of 7.6, is not heat stable, has a molecular weight of 25 000, and has a K-m of 134 mu rRNA and K-m of 1600 mug poly(C) per ml.

Animals↗
PubMed1975

Acute ischemic transection of peripheral axons in angiopathic neuropathy. No demyelination of fasciculus gracilis or decreased number or size of cytons of spinal ganglion neurons.

Demyelination (loss of myelin profiles) of posterior columns of the spinal cord in patients with neuropathy coming to autopsy usually has been interpreted as secondary to distal degeneration of peripheral nerve fibers. Previous experiments to test whether these pathologic changes could result from transecting peripheral nerves produced conflicting results. In a patient with necrotizing angiopathy in whom extensive regions of fiber transection began proximally at midthigh level, the density and diameter distribution of myelinated fibers of the fasciculus gracilis and the number and size distribution of cytons of L3 and L5 spinal ganglia have been obtained and compared with normative measurements. No discernible alteration was found, suggesting that acute degeneration of peripheral nerve fibers is not associated with loss or decrease in size of cytons of spinal ganglia or with loss or decrease in size of myelinated fibers in the fasciculus gracilis.

Acute Disease↗
PubMed1975

The clinical and pathologic correlation of fat embolism syndrome.

The fat embolism syndrome is a well-defined clinical entity that can usually be recognized in patients who have long-bone fractures. Cerebral symptoms of restlessness, confusion, stupor, and coma correlate with the autopsy findings of fat in the brain, but the amount of fat or amount of petechial hemorrhage cannot be quantitated with the severity of the cerebral symptoms. There is a correlation between the clinical manifestations of dyspnea and tachypnea and the autopsy findings in the lungs, which are heavy from edema and alveolar hemorrhage; however, we cannot correlate the degree of pathologic change in the lung, including lung weights, with the severity of findings clinically.

Accidents↗
PubMed1975

Chronic inflammatory polyradiculoneuropathy.

The diagnostic criteria, natural history, nerve conduction characteristics, pathology, laboratory features, and efficacy of corticosteroid treatment have been evaluated personally in 53 patients with chronic inflammatory polyradiculoneuropathy (CIP) who were followed up for an average of about 7.5 years. These were patients whose monophasic neurologic deficit had not crested by 6 months, patients with recurrences, and patients with a steady or stepwise progression. The typical features of CIP include absence of an associated disease, frequent history of preceding infection or receipt of foreign protein, and tendency to involve cranial, truncal, and proximal as well as distal limb structures and to have diffusely slow conduction velocity of peripheral nerves. The most marked slowing is often very proximal. The pathologic features include serous edema, mononuclear cell infiltrates (especially in perivascular areas, but without evidence of vasculitis), macrophage-induced segmental demyelination, and hypertrophic neuritis. If our patients are representative, complete recovery occurs only infrequently; about 60% of patients are able to be ambulatory and work, 25% become confined to a wheelchair or become bedridden, and approximately 10% die from their disease. Although the bulk of the pathologic changes affect spinal roots and proximal nerves, the brain and spinal cord may be involved also. Degeneration into linear rows of myelin ovoids is the predominant type of myelinated fiber degeneration of the sural nerve at the ankle.

Adolescent↗