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Biomedical subjects

T Umezaki

Publications and source records attributed to T Umezaki.

32 records · Page 2Linked to original sources
PubMed1995

Convergence of laryngeal afferents with different natures upon cat NTS neurons.

To clarify the convergence of laryngeal afferents within the nucleus tractus solitarius (NTS) in the cat, we examined in the medulla the response characteristics of superior laryngeal nerve (SLN) fibers and NTS neurons to mechanical and chemical stimulation applied to laryngeal mucosa by extracellular recordings. The response was recorded in 75 SLN primary afferent fibers (PAFs) and 92 NTS neurons. PAFs of the SLN consisted of numerous monomodal mechanosensitive fibers and a small number of chemosensitive and polymodal fibers. On the other hand, the majority of NTS neurons had a polymodal nature. Thus, laryngeal information is considered to be integrated in modality into NTS neurons. All mechanosensitive fibers received information from a small restricted field in the larynx. On the contrary, each NTS neuron responded to mechanical stimulation over a wide laryngeal field, indicating that information from different sites spatially converge on NTS neurons. Our results suggest that caudal NTS neurons play a cardinal role in integrating laryngeal afferents, which are thought to elicit laryngeal reflexes.

Afferent Pathways↗
PubMed1994

Contact granulomas of the larynx.

Ten cases of intubation granulomas and eight cases of contact granulomas not related to intubation were reviewed for the purpose of clinical analysis and pathological investigation. Granulomas were located primarily at the vocal process of the arytenoid cartilage. Additionally, 58 hemilarynges obtained from 37 cadavers with intubation granulomas were evaluated grossly and histopathologically. The intubation granulomas had no side predilections. All eight contact granulomas occurred in males and had a higher incidence of recurrence (three of eight cases) despite complete removal with laser surgery. In an attempt to explain recurrences of these contact granulomas, all three cases were studied clinically and pathologically. Results indicated that they recurred in singers and vocal abusers, and presumably resulted from the continued hammering of one vocal process against the other. Analysis also demonstrated that vocal rehabilitation was essential prior to or immediately after removal of the granuloma to prevent its recurrence. Pathological evaluation of the contact granulomas revealed focal ulceration and a covering of necrotic tissue with desquamating epithelium. The propria mucosa was edematous and infiltrated by chronic inflammatory cells and neutrophils forming focal granulation tissue in a stroma containing proliferated capillaries. Pathological features around local ulcerations were typical of a secondary granuloma while underlying arytenoid cartilage was partially necrotic.

Adult↗
PubMed1993

A trial of individual dose intensity and relative performance factors in tegafur maintenance chemotherapy for head and neck cancer.

Tegafur (Sunfural-S), as masked compound of a 5-fluorouracil derivative, was administered orally as a maintenance chemotherapeutic agent at a dose of 600 mg/day in 98 cases of head and neck epithelial cancer. The effectiveness of the drug was evaluated by a statistical method involving two formulae: individual dose intensity (IDI) and relative performance (RP). When comparing patients rated above a reference IDI value of 1.0 with those rated below 1.0, it was not possible to predict patient survival or tumor-free rates. In contrast, the value of the RP did show such a correlation. These findings support the effectiveness of Tegafur as a maintenance chemotherapeutic treatment for head and neck cancer patients.

Aged↗
PubMed1993

Origin of laryngeal sensory-evoked potentials (LSEPs) in the cat.

Sensory-evoked potentials elicited by electrical stimulation of the superior laryngeal nerve were recorded at the dural surface on the cortex and the caudal medulla in anesthetized cats as a reflection of activities in the central afferent systems. These evoked potentials were named laryngeal sensory evoked potentials (LSEPs). LSEP was mainly composed of five components, N1, N2, N4, N12, and large biphasic potential (LBP). The peak latencies of these components were as follows: N1, 1.09 +/- 0.18 ms; N2, 1.93 +/- 0.19 ms; N4, 3.97 +/- 0.19 ms; and N12, 12.48 +/- 1.01 ms. LBP was a large component lasting from approximately 6 ms to 18 ms. The generator sources of these components were identified as follows: N1, nodose ganglion; N2, presynaptic potentials of the nucleus tractus of solitarius (NTS); N4, NTS complex including the postsynaptic potentials; and N12, activities of the frontal part of the orbital gyrus. The LBP was speculated to be generated from certain subcortical structures, such as the amygdala, the thalamus, the hypothalamus, and the basal ganglia.

Animals↗
PubMed1993

Detection of largyneal sensory-evoked potentials (LSEPs) in the cat.

We previously reported on evoked potentials elicited by electrical stimulation of the superior laryngeal nerve at an appropriate site on the dural surface as a reflection of activities in the brain stem and cortex in anesthetized cats. This evoked potential was called the laryngeal sensory evoked potential (LSEP). In this study we attempted to establish a less invasive procedure for measuring LSEP. The procedures were recording on the scalp using chloride-coated silver disk electrodes and stimulation by insertion of a bipolar platinum hooked wire electrode into the laryngeal mucosa. Evoked potentials could be detected using these less invasive procedures. The response morphologies and relative timing of LSEP components were quite similar for each method in a given cat. However, the amplitudes were slightly lower and the latencies were slightly prolonged with the less invasive techniques. These results suggest that this LSEP method might be applicable to human beings as a noninvasive method for evaluating the function of the laryngeal sensory pathway.

Animals↗
PubMed1992

Intracordal injection increases glottic closing force in recurrent laryngeal nerve paralysis.

Glottic closing pressure during swallowing was measured in the cat with a catheter pressure transducer to study the effectiveness of intracordal injection in increasing glottic pressure in unilateral recurrent laryngeal nerve paralysis. Swallows were elicited by pouring water into the pharynx while the animal was under light anesthesia with ketamine. Peak pressure of the glottic closure for the control group during deglutition was 68.0 +/- 10.5 mm Hg (mean +/- standard deviation). Peak pressure decreased to 22.0 +/- 3.6 mm Hg just after sectioning of the unilateral recurrent laryngeal nerve, and rose to 39.8 +/- 8.3 mm Hg by silicon injection into the paralyzed vocal fold. In a study of chronic cases 1 month or more after unilateral recurrent laryngeal nerve section, peak pressure was 49.1 +/- 23.4 mm Hg, and varied widely from 21 to 92 mm Hg because of differences in the position of the paralyzed vocal fold and the degree of compensation by the unaffected vocal fold. In the group that had the paralyzed vocal fold fixed in the median position, peak pressure was almost the same as that of the control group. When the paralyzed vocal fold was fixed in either the paramedian or lateral position, peak pressure was 33.3 +/- 7.0 mm Hg. This value was significantly elevated to 45.8 +/- 10.4 mm Hg by injection of silicon, though it remained lower than that of the control. These results suggest that the decrease in glottic closing force during swallowing as a result of unilateral recurrent laryngeal nerve lesion is compensated for by the unaffected vocal fold to some degree and is improved by intracordal injection.

Acute Disease↗
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

Measurements of oxygen pressure in the vocal fold during laryngeal nerve stimulation.

To clarify the mechanisms of ischemic change in the vocal fold on phonation, model experiments were performed under various conditions by recording tissue oxygen pressure (Pto2) values under electrical stimulation of either the recurrent laryngeal nerves or external branches of the superior laryngeal nerves. In addition, autonomic nerve regulation of laryngeal vessels was estimated under administration of succinylcholine chloride. Oxygen pressures of the vocal fold were measured in the lamina propria and vocal muscle at the middle of the membranous portion. The Pto2 in the lamina propria showed a slight increase during lower-frequency stimulation and a slight decrease during higher-frequency stimulation of the recurrent laryngeal nerve. The Pto2 in the vocal muscle showed a decrease during stimulation of the recurrent laryngeal nerve. On the other hand, the Pto2 showed almost no change in the lamina propria or vocal muscle during stimulation of the external branch of the superior laryngeal nerve. It is supposed that an ischemic change in the vocal muscle on phonation results mainly from contraction of the vocal muscle. On the contrary, the ischemic change in the vocal mucosa on phonation does not appear to be directly caused by the contraction of the vocal muscle but by other factors, such as wavelike movement.

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↗
PubMed1987

An experimental study of the circulation of the vocal fold on phonation.

The ischemic change of the vocal fold on phonation was studied with an oxygen electrode using the canine vocal fold. Oxygen pressures of a limited area of the vocal fold were measured in the lamina propria and vocal muscle at the middle of the membranous portion. The results are summarized as follows: oxygen pressure in each area decreased on phonation as compared with respiratory movement, an ischemic change of the vocal fold occurred on phonation, and the response in the lamina propria was less than that of the vocal muscle.

Animals↗
PubMed1977

A new diagnostic aid in traumatic hemobilia.

A case report of traumatic hemobilia following suture of superficial laceration of the liver is presented. The diagnosis was confirmed by emergency endoscopy preoperatively. Segmental hepatic resection was successful. Endoscopy is the most convenient as well as harmless procedure in establishing the diagnosis preoperatively. The importance of careful observation of the papilla of Vater in endoscopy to determine the site of upper gastrointestinal hemorrhage is emphasized. In addition, the introduction of serial endoscopy to follow the course of mild hemobilia is suggested.

Adult↗