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Biomedical subjects

I Morikawa

Publications and source records attributed to I Morikawa.

10 recordsLinked to original sources
PubMed1998

Nitric oxide modulates premature renal circulation in hypoxic newborn piglets.

We studied the role of nitric oxide (NO) on the regulation of blood flow in the immature kidney during hypoxia, resuscitation and the recovery period using the NO inhibitor N(omega)-nitro-L-arginine (L-NNA) in a newborn piglet model, and the possibility of urinary cGMP as an index of renal function. After administration of L-NNA, the blood flow in both the cortex and medulla significantly decreased, indicating that NO is constantly released to maintain renal circulation. During hypoxia, the renal blood flow fell remarkably, and there were no differences between the control and L-NNA groups. During the post-resuscitation period, the recovery of renal blood flow was significantly suppressed in L-NNA administration, and it was speculated that NO might be an important factor for recovery of circulation from vasoconstriction due to hypoxemia. Urinary cGMP/cr was significantly increased on recovery from hypoxemia and was suppressed by L-NNA administration. This result suggested that the change in cGMP/cr represents renal blood flow change. We conclude that NO may play an important role in maintaining basal hemodynamics, and may also be a crucial factor for recovery from post-hypoxic vasoconstriction in premature kidneys. Urinary cGMP/cr might serve as one of the indices for assessment of premature renal circulation.

Animals↗
PubMed1994

Patients' rights in Japan: progress and resistance.

The discussion of patients' rights in Japan began in 1968 when a surgeon was accused of violating a potential organ donor's right to life by arbitrarily employing brain-based criteria in the determination of his death. A proliferation of documents that articulate and endorse patients' rights occurred in the 1980s and early 1990s. The doctrine of informed consent, which has been a central aspect of the movement toward patients' rights, is increasingly recognized in Japan, although importance rarely has been attached to the element of the patient's "appreciation" of the information disclosed by the physician, much less to the "voluntariness" of the patient's decision. Nevertheless, recent court decisions indicate progress both in the acceptance and the understanding of the doctrine in Japan.

Bioethical Issues↗
PubMed1989

Localization of laryngeal motoneurons in the medulla oblongata of guinea pigs.

The distribution of motoneurons in the brain stem innervating the laryngeal muscles cricothyroid, posterior cricoarytenoid, and thyroarytenoid-lateral cricoarytenoid in the adult guinea pig was investigated. Horseradish peroxidase was injected into individual muscles or applied to the cut end of the superior laryngeal nerve and the recurrent laryngeal nerve. The laryngeal motoneuron pool of guinea pig is divided into two separate areas: the rostral retrofacial nucleus and the caudal nucleus ambiguus. Superior laryngeal and cricothyroid motoneurons were present only in the retrofacial nucleus, while recurrent laryngeal motoneurons were present in both the nucleus ambiguus and the retrofacial nucleus. Posterior cricoarytenoid motoneurons were located in the rostral and ventrolateral part of the recurrent laryngeal motoneuron pool in the nucleus ambiguus. The thyroarytenoid-lateral cricoarytenoid motoneurons partially overlapped the posterior cricoarytenoid pool and extended more dorsomedially and caudally in the nucleus. Our findings on the distribution of perikarya in the laryngeal motoneuron of the guinea pig are essentially the same as those of other mammals.

Animals↗
PubMed1989

Glottic closure during swallowing in the recurrent laryngeal nerve-paralyzed cat.

Glottic closing pressure and time were quantitatively analyzed during deglutition and in reflex glottic closure elicited by superior laryngeal nerve stimulation by means of a catheter pressure transducer in the cat. Duration and peak pressure of glottic closure during deglutition were 322.6 +/- 32.2 msec (mean +/- SE) and 57.5 +/- 6.0 mmHg, respectively, whereas peak pressure of the reflex glottic closure was 21.7 +/- 6.1 mmHg in control animals. When the recurrent laryngeal nerve was denervated unilaterally, decrease in peak glottic closing pressure on swallowing was only about 36%, whereas the peak pressure of reflex glottic closure was markedly diminished to 4.5 +/- 4.6%. When bilateral recurrent laryngeal nerves denervated, decrease in peak pressure during deglutition showed no greater significance than it did after unilateral denervation. Inferior constrictors myotomy in addition to bilateral recurrent laryngeal nerve denervation reduced peak pressure to nearly zero. These results indicate that on swallowing, the inferior constrictors cooperate with the intrinsic laryngeal adductors, thus playing a very important role in reinforcing glottic closure, a function that is unlikely during reflex glottic closure.

Animals↗
PubMed1988

Laryngeal reflex mechanism during deglutition--observation of subglottal pressure and afferent discharge.

In this investigation, particular attention was paid to elucidate the laryngeal reflex mechanism of protective closure and the sensory function of the larynx during deglutition. For this purpose, three different experimental procedures were adopted: (1) subglottal pressure of felines was measured during deglutition using a pressure transducer; (2) subglottal pressure of human beings was measured during deglutition using a pressure transducer; and (3) afferent discharges from superior and recurrent laryngeal nerves of felines were recorded. The following conclusions appear justified. (1) Feline and human subglottal pressure during deglutition showed the following pattern. The pressure rises with onset of deglutition, temporarily drops during laryngeal elevation, rises again during the downward movement of the larynx, and drops again at the end of the glutition. This pattern was not affected by the resection of the unilateral recurrent laryngeal nerve. (2) The superior laryngeal nerve is involved in the sensory function of the pharynx, larynx, and trachea. At least two types of afferent discharges from superficial and internal sensory nerves are suspected. Afferent discharges from the recurrent laryngeal nerves in the larynx and trachea are not as distinct as those of the superior laryngeal nerve, and this seems to correspond with various changes in the thorax. During deglutition, afferent discharges were recorded from superior to recurrent laryngeal nerves.

Animals↗
PubMed1983

Vocal fold furrows. A 10-year review of 240 patients.

A retrospective review of 240 patients with vocal fold furrows seen at the Department of Otolaryngology, Kurume University Hospital over the 10-year period from 1971 to 1980 was completed. Of the 240 patients, 173 were male and 67 were female. In 195 patients, the furrows were the major pathology causing hoarseness; in 29, the furrows were associated with other major laryngeal diseases; and, in 16, there were no voice problems. We call the first group "sulcus vocalis" in this paper. The onset of voice problems in the cases of sulcus vocalis was at the age of 40 years or older in most case, at young childhood in some, and at adolescence in some cases. Typical findings of sulcus vocalis consisted of bilateral furrows on the vocal fold edges extending over the entire length of the membranous portion, bowed vocal fold edges, glottic incompetence during phonation and excessive ventricular fold adduction. No effective treatments have been established.

Adolescent↗