PubMed Health⌕ Search

Biomedical subjects

Y Hayashida

Publications and source records attributed to Y Hayashida.

At least 163 records · Page 9Linked to original sources
PubMed1980

An intracellular study of chemosensory fibers and endings.

1. The carotid body and its nerve, removed from anesthetized cats, were placed in physiological saline flowing under paraffin oil. The nerve, lifted into the oil, was used for either electrical stimulation or recording of the total afferent discharge. Intracellular recordings were obtained from individual nerve fibers and endings within the carotid body. The recording sites were identified by injecting Procion yellow through the intracellular electrodes; the tissues were then prepared for histology and observed with episcopic fluorescence or Nomarski optics. 2. Intracellularly recorded chemosensory fibers conducted at 1.1-30 m/s and usually displayed action potentials of regular amplitude. At times, however, some spikes become partially blocked while others maintained their original amplitude. "Natural" (hypoxia) or chemical (ACh or NaCN) stimulation induced different patterns of frequency changes of the large and small action potentials. This indicated nerve fiber branching at some distance from the recording site. 3. Intra- and extracellularly recorded spikes were blocked in 0 [Na+]0 by tetrodotoxin (TTX) or procaine. 4. During chemical stimulation, a slowly occurring depolarization (receptor or generator potential) was recorded intracellularly from the afferent fibers. It developed concomitantly with the increase in discharge. 5. Impalement of single nerve terminals (histologically identified) showed numerous "spontaneous" depolarizing potentials (SDPs) that had a mean amplitude of 5.6 mV, a mean duration of 46.1 ms, and nearly random distribution. They increased in frequency and summated during chemical stimulation. SDPs originated from either the site of recording or from neighboring areas. When the SDPs attained a certain amplitude, they seemed to give rise to action potentials. Also, relatively well developed or partially blocked spikes (apparently originating elsewhere) were recorded from single nerve terminals. 6. The receptor (generator) potential of chemosensory receptors appears to be an integrated response formed by multiple activity originating in different nerve endings.

Acetylcholine↗
PubMed1979

Congenital pyloric atresia--a report of two cases.

Two cases of the membranous type of pyloric atresia are described and a review of 99 cases reported in the literature is presented. Excision and incision of diaphragm with pyloroplasty was performed on both cases. The first patient was alive following the second operation of gastroduodenostomy for postoperative stenosis. The second premature patient died of sepsis on the 58th postoperative day. The treatment should be surgical and the operative procedure should be chosen depending on the type of atresia. Excision or incision of the diaphragm with pyloroplasty and gastroduodenostomy are the procedures of choice. Gastrojejunostomy should be avoided because of its high mortality rate.

Duodenum↗
PubMed1978

Zinc deficiency during total parenteral nutrition in childhood.

Changes in plasma zinc levels were studied in 11 pediatric surgical patients treated with total parenteral nutrition. Plasma copper levels were also determined in some patients. In three patients plasma zinc fell to a very low level during long-term total parenteral nutrition, and a syndrome of zinc deficiency developed characterized by dermatitis, alpecia, and enterocolitis with striking response to intravenous zinc therapy. In contrast, plasma zinc levels in the patients with short-term total parenteral nutrition remained in the normal range during the present study. This suggests that one of the mechanisms of zinc deficiency during total parenteral nutrition is insufficient amount of zinc in the nutritional solutions for long-term use, especially for older children. Symptoms of the zinc deficiency also occurred in these patients during the anabolic phase, suggesting that tissue demand for zinc may be increased at that time. Therefore, zinc should be included, on a regular basis, in all parenteral nutritional solutions in amounts sufficient to meet estimated needs for growth and tissue repair.

Adolescent↗
PubMed1978

Quantal analysis of the size of excitatory post-synaptic potentials at synapses between hair cells and afferent nerve fibres in goldfish.

1. A statistical analysis has been made of the transmitter release at the hair cell afferent fibre synapse in the sacculus of the goldfish, using the amplitude of the excitatory post-synaptic potentials (e.p.s.p.s) in response to stimulus tone as a measure of the transmitter release under application of tetrodotoxin. 2. Application of binomial statistics allowed a direct calculation of the mean probability of release (p) and the readily available store (n), and the X2-test showed that the binomial predictions fitted fairly well with the observed distribution of the responses. 3. Adaptive rundown of e.p.s.p.s during sound stimulation, i.e. the successive rundown in the size of the mean quantal content (m), was found to be associated with a reduction in the size of parameter n, but not of p. 4. A marked negative correlation was demonstrated between the amplitude of two consecutive e.p.s.p.s, supporting the depletion hypothesis of the adaptive rundown of e.p.s.p.s. 5. The increase in the e.p.s.p. amplitude and the increase in the mean quantal content, m, brought about by an increase in the tone intensity were found mostly explicable in terms of an increase in the statistical parameter n. The probability parameter p was found largely in invariable, although in certain instances the increase in m was also accompanied by a slight increase in the parameter p.

Animals↗
PubMed1975

Intestinal atresia in fetal dogs produced by localized ligation of mesenteric vessels.

Experimental ileal atresia and stenosis were produced by a localized ligation of the mesenteric vessels in fetuses from 13 pregnant mongrel dogs having gestational ages of 45-55 days. The intestinal infarct in the fetus was characterized by an aseptic coagulation necrosis selectively limited to the mucosa and submucosa, and also by intense hyperemia and minimal cellular reaction in the adjacent tissue. Eleven days after the devascularization, type 2 intestinal atresia, in which there is a long cord between the blunt ends microscopically similar to that seen in humans.

Animals↗