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Biomedical subjects

Y Fukuda

Publications and source records attributed to Y Fukuda.

At least 1,063 records · Page 59Linked to original sources
PubMed1979

Infantile GM1-gangliosidosis with marked manifestation of lungs.

GM1-gangliosidosis is a disease characterized by abnormal accumulation of GM1-ganglioside in the brain and viscera. The disease is characterized by clinical findings similar to Hurler's disease and pathologic features resembling Niemann-Pick's disease but with involvement of the glomerular epithelium. A 14-month-old boy, clinically diagnosed as GM1-gangliosidosis, died of respiratory insufficiency and was autopsied except for the brain. Biochemically, marked increase of GM1-ganglioside in the viscera was demonstrated. Pathologically, the foam cells were present in the viscera. Some parts of the cytoplasmic vacuoles in the lungs and spleen contained osmiophilic fibrillar material electron-microscopically. This case was characterized by marked accumulation of foam cells in the pulmonary alveolar spaces.

Foam Cells↗
PubMed1979

Receptive-field properties of cells in the dorsal part of the albino rat's lateral geniculate nucleus.

Receptive-field properties of 273 relay (principal, P-) cells of the dorsal lateral geniculate nucleus (LGd) were studied in urethane-anesthetized albino rats, in an attempt to see if there is some relation between the visual property and the conduction velocity of afferent optic nerve fibers. According to properties of the receptive-field center, P-cells were classified into two types, common (89%) and uncommon (11%). The common type consists of OFF-phasic, ON-phasic, ON-tonic and ON-OFF-phasic cells, while the uncommon type includes ON-inhibited, moving-sensitive, ON-OFF-inhibited, simple-cell-like and complex-cell-like cells. The mean response latency to single optic chiasm shocks increases in the order of OFF-phasic (1.94 msec), ON-phasic (2.35 msec), ON-tonic (2.87 msec), ON-OFF-phasic cells (3.04 msec) and uncommon type (3.18 msec). The mean size of the receptive-field center in each of the four common types was smaller than that in the uncommon type; 6 degrees--7 degrees vs. 11 degrees. From responsiveness to moving light spots with speeds faster than 25 degrees--30 degrees/sec, P-cells of the common type were divided into the fast- and slow-movement-sensitive cells. The ratio of occurrences of fast- to slow-movement-sensitive cells decreases in the order of the OFF-phasic (2.7), ON-phasic (2.4), ON-tonic (1.1) and ON-OFF-phasic types (0.06). The optic chiasm latencies were shorter than 2.5 msec in most of the fast-movement-sensitive cells while the reverse was true for most of the slow-movement-sensitive cells. From these findings discussions were made to point out that the rat LGd mainly consists of Y- and W-like P-cells and that the Y/W dichotomy of P-cells approximately corresponds to the previously established fast/slow classification.

Animals↗
PubMed1978

Induction by degraded carrageenan of colorectal tumors in rats.

Degraded carrageenan derived from the red seaweed Eucheuma spinosum was given to Sprague-Dawley rats through the diet, in drinking water or by stomach tube for up to 24 months. Carrageenan-induced squamous cell carcinomas, adenocarcinomas and adenomas in the colorectum were observed. Some rats had metastases to the regional lymph nodes of squamous cell carcinomas. These results show that degraded carrageenan is carcinogenic to the colorectum of the rat.

Adenocarcinoma↗
PubMed1978

Characteristics of optic nerve innervation in the rat superior colliculus as revealed by field potential analysis.

With lightly anesthetized rats, field responses to single optic nerve (ON) and optic chiasm shocks were studied in superficial layers of the superior colliculus, i.e., St. zonale (SZ), St. griseum superficiale (SGS) and St. opticum (SO). Based upon characteristics in the depth profile of the field response within the superficial layers, we identified three zones of N3, N2, and N1 from the SZ in this order. The narrow N2-zone was localized around the middle part of the SGS and less distinct than the other two zones. The N3-zone was characterized by a N3-wave and the N1-zone with N1- and P3-waves. N3- and P3-waves were activated by slowly conducting ON fibers (5.0 +/- 1.4 and 4.2 +/- 0.6 m/sec, respectively) while the N1-wave was by fastest conducting fibers (16.3 +/- 4.1 m/sec). According to recent Golgi studies, hypothetical mechanisms underlying the three waves were proposed: the N3-wave was ascribed to the activities of small vertical fusiform cells in the SZ or the upper half of SGS, the N1-wave to those of narrow field vertical cells which predominate in the lower half of SGS, and the P3-wave to those of wide field vertical cells whose somata are in the lower half of SGS or in the SO. The N3-, N1-, and P3-waves were found to differ from each other in recovery function tested with double ON shocks as well as in the topographical analysis of amplitudes through a whole extent of the colliculus. The three systems represented by the three waves were suggested to play different roles in visual information processing within the superficial strata.

Animals↗
PubMed1978

A four group classification of the rat superior collicular cells responding to optic nerve stimulation.

With lightly anesthetized rats, activities of single cells responding to single optic nerve (ON) shocks were recorded from the superficial layers of the superior colliculus, i.e., St. zonale(SZ), St. griseum superficiale (SGS) and St. opticum (SO). According to response latencies and recording depths, four classes of cells were identified: I-, II-, III-, and IV-cells. Class I cells, recorded in the SZ or the upper half of SGS, were innervated by slowly conducting ON fibers of velocities slower than 4 m/sec. Class II cells, recorded from the middle part of the SGS, were innervated by ON fibers of intermediate velocity (4--8 m/sec). Class III cells, recorded from the lower half of SGS or the upper part of SO, were innervated by fast conducting ON fibers (faster than 8 m/sec). Class IV cells were recorded from the depth similar to the class III but they were innervated by slowly conducting fibers (4-1.7 m/sec). Class I cells revealed a long-lasting inhibition after initial excitation, being a sharp contrast with cells of classes II and III which were almost free from inhibition. Inhibition exerted upon class IV cells were of intermediate strength. Possible anatomical correlates of the four classes of cells and hypothetical modes of their ON innervation were discussed.

Action Potentials↗
PubMed1978

Visual receptive-field properties of single cells in the rat superior colliculus.

Receptive-field properties were studied in single cells in the visual layer of the albino rat's superior colliculus. All the samples (N = 195) were identified as one of the four classes (I-, II-, III- and IV-cells) which were established previously on the bases of the response properties to single shocks to the optic pathway and of the recording sites. The four classes were located more deeply in the superior colliculus roughly in the order of from I to IV. Response latencies to single shocks to the optic chiasm were shortest in the III-cells, intermediate in the II-cells and longest in the I- and IV-cells. These cell classes turned out to be different from each other in a number of visual properties. 1) Receptive-field centers in the I- and II-cells (N = 26 and 27, respectively) were of either the ON-OFF or the ON type. Of class III (N = 47), one subgroup (IIIa) consisted mostly of the OFF type whereas the other (IIb) was made up mostly of the ON-OFF type. About two-thirds of the IV-cells (71/95) were of either the ON, the OFF or the ON-OFF type; except for two cells, the rest were all of the moving-sensitive type. 2) The average size of the receptive-field center was small (5.4 degrees +/- 2.3 degrees) in the class I, intermediate in the classes II and III (8.1 degrees +/- 2.1 degrees and 7.1 degrees +/- 2.7 degrees, respectively) and large in the class IV (18.1 degrees +/- 15.9). 3) Responsiveness to moving light stimuli (speeds, 40 degrees--90 degrees/sec) decreased in the order of IIIa, II and IIIb, and I and IV. 4) Maintained activity was lower in the superficially located cells (I, II and IIIa) than in the deeply located ones (IIIb and IV).

Afferent Pathways↗
PubMed1978

Relationship between sperm concentration and polyspermy in intact and zona-free mouse eggs inseminated in vitro.

Intact and zona-free mouse eggs were cultured with preincubated (capacitated) spermatozoa for 1 or 4 hr. High proportions of eggs (84%--100%), examined either 1 or 4 hr after insemination, were undergoing fertilization in the intact and zona-free eggs in sperm concentration from 25--800 X 10(3) sperm/ml. The average number of spermatozoa attached to the zona pellucida and to the vitellus was only slightly increased as the sperm concentration increased. Polyspermy was increased from 25--200 X 10(3) sperm/ml but there was no clear correlation between the incidence of polyspermy and further increase of sperm concentration in both the intact and zona-free eggs. Besides a functional zona reaction, there was a definite vitelline block to further sperm entry. It seems that due to the chance collision of sperm and egg with the subsequent formation of a block mechanism in the zona pellucida and in the vitelline membrane within a short time, polyspermy cannot be increased by further increase of sperm concentrations.

Animals↗