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Biomedical subjects

K Kaga

Publications and source records attributed to K Kaga.

At least 55 records · Page 3Linked to original sources
PubMed2000

Effectiveness of the fold plication method in lung volume reduction surgery.

OBJECT: The fold plication method is a new operative procedure for lung volume reduction surgery whereby the target area is obliterated by plicating the folded tissue using a knifeless stapler, without the use of bovine pericardium. The effectiveness of this new method was evaluated in patients with advanced pulmonary emphysema. PATIENTS AND METHODS: Two weeks before and 6 months after surgery, pulmonary function, static lung compliance, maximal esophageal pressure, maximal inspiratory and expiratory mouth pressures, 6-min walking distance and the Borg scale were determined in twenty consecutive patients who underwent video-assisted thoracoscopic unilateral surgery. RESULTS: There was an increase in forced expiratory volume in one second (31%), forced vital capacity, peak expiratory flow rate and maximal voluntary ventilation, and a decrease in functional residual capacity (-16%) measured by plethysmograph. Static lung compliance decreased, and maximal esophageal pressure, and maximal inspiratory and expiratory mouth pressures increased. The 6-min walking distance increased (20%) and the Borg scale decreased (5.9 to 3.5). CONCLUSION: The results compare favorably with those obtained with other methods. Thus, the fold plication method could be considered an alternative procedure for lung volume reduction surgery.

Aged↗
PubMed2000

Is it permissible to omit mediastinal dissection for peripheral non-small-cell lung cancers with tumor diameters less than 1.5 cm?

BACKGROUND: Recently the pros and cons of limited surgery for small-sized peripheral non-small-cell lung cancers (PNSCLCs), such as omission of mediastinal dissection, etc., have been vigorously debated. We analyzed whether hilar/mediastinal lymph node metastases were present in 30 small-sized PNSCLCs. MATERIAL AND METHODS: In the nine years from 1990 to 1998, 294 lung cancer patients underwent lobectomy or pneumonectomy combined with hilar/mediastinal dissection in the Tokai University Hospital. Thirty of these patients diagnosed as having cT1N0M0 PNSCLC with tumor diameters of 1.5 cm or less by computed tomography, are evaluated in this article. RESULTS: The 30 PNSCLC patients consisted of 14 males and 16 females with a mean age of 61 +/- 9 years. Twenty six patients (87%) had no hilar nor mediastinal lymph node metastases (pN0), one patient (3%) had a hilar lymph node metastasis (pN1), and three patients (10%) had mediastinal lymph node metastases (pN2). CONCLUSIONS: Mediastinal lymph node metastases were histologically observed in 3 (10%) of 30 PNSCLC patients with tumor diameters of 1.5 cm or less. Our results show that mediastinal dissection is still necessary even for small-sized lung cancers.

Carcinoma, Non-Small-Cell Lung↗
PubMed1999

Vestibular compensation in infants and children with congenital and acquired vestibular loss in both ears.

In children with semicircular canal anomalies, vestibular compensation during their development and growth was studied. The damped rotation test elicited 'absence or poor per-rotatory nystagmus and absence of post-rotatory nystagmus in all cases. Development of gross motor and balance function was seriously delayed in each case during the first 2 or 3 years of life. Thereafter, during the pre-school age, all children could achieve most landmarks of motor development, such as head control, independent walking and running. However, balance functions at the age of entrance of the elementary school (6 years old) were variously impaired in each case. The better case could swim under water but the poor case could not maintain static balance with eyes closed. These motor skills due to vestibular compensation presumably depend on integration of the compensatory input from visual, somatosensory and proprioceptive senses, and the maturation of motor control systems in the cerebellum, basal ganglia and motor cortex.

Basal Ganglia↗
PubMed1999

Cochlear histopathology associated with mitochondrial transfer RNA(Leu(UUR)) gene mutation.

Using dot-blot hybridization and Southern blotting, the authors detected a point mutation at nucleotide pair (np) 3243 in mitochondrial DNA from temporal bone sections of a woman with diabetes and deafness. The mutation could not be detected with agarose gel electrophoresis, suggesting that the degree of heteroplasmy is low. Histologically, there was marked degeneration of the stria vascularis and outer hair cells throughout the cochlea, as well as a reduction of spiral ganglion cells in the base. These findings suggest that the mutation affects these inner ear structures preferentially and that deafness can occur even when the proportion of np 3243 mutation is low.

Cochlea↗
PubMed1999

Temporal bone histopathologic findings in a case of interstitial deletion of the long arm of chromosome 2 [del(2) (q31q33)].

The temporal bones of a 24-day-old female neonate with an interstitial deletion of the long arm of chromosome 2 [del(2)(q31q33)] were studied histopathologically, focusing mainly on the inner ear. This is, to our knowledge, the first report of a temporal bone study in a case of this chromosomal aberration. The abnormalities included a shortened cochlea with underdeveloped modiolus in both ears. Total absence of the spiral ganglion cells and the cochlear nerve bundle, accompanied by obliteration of the fundus of the internal auditory meatus by a bony plate, and dislocation of some geniculate ganglion cells to the internal auditory meatus were also observed in the right ear. The absence of the spiral ganglion cells is considered to be the result of some complication in the early fetal life, such as dysgenesis or early degeneration of the neuronal cells. The organ of Corti in the right ear was well-developed and preserved in the middle turn, suggesting that the differentiation of the cochlear sensory epithelium in humans is not dependent upon the innervation, at least on the gross level.

Abnormalities, Multiple↗
PubMed1999

Olfactory neuron-specific expression of NeuroD in mouse and human nasal mucosa.

Human olfactory neuroepithelium (OE) is situated within the olfactory cleft of the nasal cavity and has the characteristic property of continually regenerating neurons during the lifetime of the individual. This regenerative ability of OE provides a unique model for neuronal differentiation, but little is known about the structure and biology of human olfactory mucosa. Thus, to better understand neurogenesis in human OE, we studied the expression of olfactory marker protein (OMP), TrkB and NeuroD in human nasal biopsies and autopsy specimens and compared these data with those obtained from normal and regenerating mouse OE. We show that NeuroD and TrkB are coordinately expressed in human OE. Thus, by using these markers we have been able to extend the known boundaries of the human OE to include the inferior middle turbinate. In normal mouse OE, TrkB and OMP expression overlap in cells closest to the superficial layer, but TrkB is expressed more strongly in the lower region of this layer. In contrast, NeuroD expression is more basally restricted in a region just above the globose basal cells. These characteristic expression patterns of OMP, TrkB and NeuroD were also observed in the regenerating mouse OE induced by axotomy. These results support a role of NeuroD and brain-derived neurotrophic actor (BDNF), the preferred ligand for TrkB, in the maintenance of the olfactory neuroepithelium in humans and mice.

Adult↗
PubMed1999

Application of the fold plication method for unilateral lung volume reduction in pulmonary emphysema.

BACKGROUND: Unilateral lung volume reduction procedures are used to treat pulmonary emphysema. The most significant technical problem with this operation is an air leak from the pulmonary stump. Bovine pericardium has been used to prevent air leaks but is associated with interstitial pneumonia and a high cost. METHODS: The fold plication method was devised to prevent postoperative air leaks to avoid interstitial pneumonia, and to decrease cost. This technique was applied in 20 consecutive patients with emphysema who underwent a unilateral lung volume reduction operation via a thoracoscopic two windows approach. RESULTS: The operative time was approximately 1 hour. There was minimal postoperative bleeding, no persistent air leaks, and no evidence of pneumonia. Pulmonary function improved in all patients. CONCLUSIONS: The unilateral fold plication method is an economical and safe alternative to bovine pericardial patching after lung volume reduction operation to prevent stump air leaks.

Adult↗
PubMed1999

Development of blood-labyrinth barrier in the semicircular canal ampulla of the rat.

Cationic polyethyleneimine (PEI) administered intravenously was transported to anionic sites on the capillary and subepithelial basal laminae (BL) in the vestibular labyrinth. Therefore, changes in the PEI distribution on the BL reflect changes in the transport system in the vestibular labyrinth. A 0.1% PEI solution was administered intravenously (7.5 ml/kg) to developing (1, 4, 7, 14 days after birth) and adult rats in order to investigate the development of the macromolecular transport in the ampulla of the semicircular canal as a function of age. After 1 h, the bony labyrinth was removed and embedded in Epoxy resin. Ultrathin sections of the ampulla were then examined with a transmission electron microscope. In the subepithelial BL in the dark cell area and capillary BL in the crista ampullaris, the PEI distribution in both 1- and 4-day-old rats was markedly increased compared to that in either 7-, 14-day or adult rats. In the sensory cells in 1-, 4-day or 7-day-old rats, PEI density and area was significantly greater than in the adult rats. These findings suggest that the macromolecular transport system in the developing rat ampulla becomes mature by 14 days after birth and that the maturation of its transport system in the ampulla is strongly associated with that in the stria vascularis.

Animals↗
PubMed1999

Auditory brainstem responses, electrocochleograms, and cochlear microphonics in the myelin deficient mutant hamster 'bt'.

Electrophysiological studies of the auditory pathway were performed on the mutant hamster 'bt' which is known to have myelin deficiencies in the central nervous system. Auditory brainstem responses (ABRs), electrocochleograms (EcochGs), and cochlear microphonics (CMs) were recorded. ABRs in 'bt' demonstrated markedly transformed waveforms with significantly prolonged latencies. EcochG in 'bt' showed significantly prolonged N1 latencies of the compound action potentials (CAPs) while 'bt' showed normal CMs. The myelin deficient mutant hamster 'bt' may have myelin deficiencies not only in the brainstem auditory pathway but also in the cochlear nerve.

Animals↗
PubMed1999

The long-term effect of bilateral inferior colliculus ablation on auditory brainstem response in awake cats.

In this study auditory brainstem responses (ABRs) were recorded repeatedly in three awake cats before and after bilateral aspiration of the inferior colliculi (ICs). All surgical procedures were performed under anaesthesia with Nembutal. Postoperative recordings were obtained 1 week, 3 months, 8 months and 13 months after bilateral aspiration of the ICs in order to study the long-term changes in ABRs. The P5 amplitude was markedly reduced only at 1 week after aspiration. P1 and P2 amplitudes were affected slightly at 3 months and 1 year, but those of P3 and P4 decreased significantly. After perfusion of these cats, histological examination of the brainstem revealed complete ablation of both ICs, neuronal loss in the nucleus of the lateral lemniscus and the superior olivary complex and preservation of the cochlear nucleus. Our results suggest that retrograde degeneration of neuronal cells of the brainstem, which project to the IC from the nucleus of the lateral lemniscus and superior olivary complex except the cochlear nucleus, affect the peak amplitudes of the ABR over the long-term.

Animals↗
PubMed1999

[Preoperative evaluation of cardiac disease for patients with lung cancer: usefulness of treadmill exercise electrocardiogram].

118 patients with lung cancer who underwent treadmill exercise electrography (ECG) as part of their preoperative evaluation, were investigated for postoperative events. On the treadmill exercise ECG 27 patients were positive and 91 were negative. The more elderly patients tended to reveal ischemic findings in treadmill exercise ECG. Of the 71 patients with normal of result by ECG at rest, 15 patients (21.1%) had postoperative ischemic change on ECG. As a result, it was considered that this examination was insufficient to detect latent ischemic heart disease. The patients who had a discontinued at stage 2 or less of the Bruce protocol and had a negative result by treadmill exercise ECG, were classified as insufficient group and separated from the others. (27/118 patients). This group consisted of advanced age (p < 0.05) who tended to experience postoperative events. In the sufficient group, patients showed ischemic events predominantly on ECG at postoperative period (p < 0.01). We concluded that as preoperative screening of heart disease prior to lung cancer surgery ECG at rest was not adequate while treadmill exercise ECG was useful.

Adult↗
PubMed1999

Thoracoscopic diagnosis and treatment of mediastinal masses. Usefulness of the Two Windows Method.

BACKGROUND: We report on the usefulness of thoracoscopic surgery by the Two Windows Method in mediastinal diseases. While the positioning of the two-window skin incisions was originally decided for lung cancer, but we have been using precisely the same method to biopsy and remove mediastinal lesions. METHODS: Thoracoscopic surgery by the Two Windows Method was performed in 40 cases in which it had been impossible to make a diagnosis by noninvasive methods. Access to the pleural cavity was achieved by making skin incisions in two places anterior and posterior to the inferior angle of the scapula in the fourth intercostal space. RESULTS: Biopsy was performed in 17 of the 40 patients to make a histological diagnosis. It was possible to make a definitive histological diagnosis in all of the patients. Complete resection of a mediastinal tumor was performed in 23 patients, and the resection was concluded thoracoscopically by the Two Windows Method in 22 of these patients (95.7%), with the only exception of one patient in whom we converted to standard thoracotomy because of intraoperative bleeding. There were no postoperative complications and no perioperative deaths. CONCLUSIONS: We conclude that the Two Windows Method is also useful for the diagnosis and complete resection of mediastinal diseases and that this is a low-invasive and safe method.

Adolescent↗
PubMed1999

Temporal bone pathology findings due to drowning.

It has been reported that anoxia due to near-drowning or near-suffocation causes brain damage but not inner ear damage. On the other hand, it has been shown that brain death causes both brain damage and inner ear damage. However, studies of temporal bone pathology resulting from sudden death due to drowning are few. We studied temporal bone pathology in six cases of individuals who died of accidents due to drowning. In all temporal bones examined, we found extensive congestion petechiae and haemorrhage in the vessels in the mucosal layers of the middle ear and mastoid air cells, as well as in the vessels around the facial nerve and carotid canal. In the inner ear, there was no abnormality in Corti's organ or the vestibular organs, except in one case who died in the bath. Our findings suggest that petechiae haemorrhage or congestion in the vessels of the mucosal layer and the vessels themselves of the middle ear occurs upon acute death due to drowning.

Adolescent↗
PubMed1999

Usefulness of video-assisted thoracic surgery (Two Windows Method) in the treatment of lung cancer for elderly patients.

BACKGROUND: We have been performing it less invasively by making just two, small skin incisions (Two Windows Method) for lung cancer surgery. We assess the usefulness of VATS by the Two Windows Method in elderly patients. METHODS: The subjects were 32 of the 75-year-old or older patients with primary lung cancer in our department. We assessed cases in which thoracotomy was performed and the cases in which VATS by Two Windows Method was performed, and compared postoperative complications, hospital deaths, and postoperative length of stay. RESULTS: Operations by video-assisted thoracic surgery (VATS) by the Two Windows Method were completed in 20 of the 32 patients, and a conversion to thoracotomy was done in two patients (rate 9%). Ultimately, thoracotomy was performed in a total of 12 cases, including these two. In the thoracotomy patients, the most common postoperative complication was pneumonia/atelectasis (4 cases) secondary to poor sputum expectoration. There were 2 hospital deaths due to septicemia, and there was 1 due to pulmonary artery embolism. In the VATS patients, the rate of occurrence of postoperative complications was 30%, and clearly lower than the 67% among the thoracotomy patients (p<0.05). No hospital death occurred among the VATS patients. The postoperative hospital stay of the VATS patients (21 days) was shorter than that of the thoracotomy patients (31 days), (p<0.05). CONCLUSIONS: VATS by the Two Windows Method is safer than thoracotomy, and it should be considered first for lung cancer surgery in the aged.

Adenocarcinoma↗
PubMed1998

Brain functions of an infant with hydranencephaly revealed by auditory evoked potentials.

Hydranencephaly is a severe condition of brain characterized by the almost complete absence of the cerebral hemispheres with the thalamus, cerebellum and brainstem being preserved. This paper reports hydranencephaly in a 3-month-old boy. Cranial magnetic resonance imaging (MRI) revealed the condition and an auditory evoked potential study which was performed in order to investigate residual brain function. They showed normal auditory brainstem function but no appearance of other auditory evoked potentials originating from the higher brain.

Brain↗
PubMed1998

ABR and temporal bone pathology in Hurler's disease.

This is believed to be the first report on estimating hearing loss in Hurler's disease, based on the correlation between ABR and temporal bone pathology. ABR findings revealed hearing loss to be about 70 dB or more as result of peripheral mixed impairment. A histological study of the temporal bones revealed almost all pathological findings in the conductive system, except for the hyperplastic arachnoid in the internal auditory canal. In the middle ear cavity, otitis media, residual mesenchyme and deformity of ossicles were found. We explain the conductive component to be due to otitis media and poor ossicular connection. However, the etiology of the sensorineural component remains speculative. In Hurler's disease, hearing loss with mental retardation is often found at infantile age. Therefore, assessing the extent of hearing loss exactly was difficult, for example, the severity. the etiology and incidence of sensorineural impairment. We emphasize the need for not only well-described pathological studies but also for more objective functional investigations, at least ABR.

Child, Preschool↗
PubMed1998

Mechanism of short-term memory and repetition in conduction aphasia and related cognitive disorders: a neuropsychological, audiological and neuroimaging study.

To evaluate the role of the sub-cortical white matter and cortical areas of the supramarginal gyrus in short-term memory impairment (shortened digit or letter span) and repetition difficulty, four patients with conduction aphasia and impaired short-term memory and two patients with only short-term memory impairment were given digit span, letter span, speech audiometry and dichotic listening tests. The results showed that in most of the patients letter span was inferior to digit span and that bilateral ear suppression in the dichotic listening test was observed in two patients with a lesion in the inferior part of the supramarginal gyrus, suggesting that what was affected was phonological information and that the supramarginal gyrus was the storage site. The overlapped lesion of conduction aphasia patients with short-term memory impairment was the periventricular white matter at the upper to middle part of the trigone, while patients with only short-term memory impairment had a lesion in the inferior supramarginal gyrus in common. Thus, damage to the periventricular white matter at the trigone may yield the phonemic paraphasia characteristic of conduction aphasia, while damage to the inferior part of the supramarginal gyrus may result in the impairment of short-term memory. We believe that as a part of the mechanisms of short-term memory and repetition, phonological information is processed in the primary auditory cortex and goes through the periventricular white matter to the inferior part of the supramarginal gyrus and is temporarily stored there.

Aged↗