Search PubMed⌕ Search

Biomedical subjects

Y Anzai

Publications and source records attributed to Y Anzai.

At least 73 records · Page 4Linked to original sources
PubMed1991

[Magnetic resonance imaging of small nasopharyngeal tumors].

Magnetic resonance (MR) images of 9 patients with a small nasopharyngeal tumor were examined, and among them three cases were evaluated with Gd-DTPA enhancement technique. All cases showed no asymmetry of parapharyngeal space, but they presented neck lymph nodes swelling. These cases were proved malignant by surgical procedures and the blind biopsy. MR findings of levator and tensor veli palatini muscles and retropharyngeal lymph nodes were retrospectively evaluated in correlation with endoscopic examination and biopsy. In six cases among 9 patients, MR images demonstrated tumors on the lateral wall of nasopharynx. Infiltration of levator veli palatini muscle was an especially important earlier sign of nasopharyngeal tumor invasion because the levator veli palatini muscle belongs to the intrapharyngeal muscle group. Endoscopic examination could not reveal any abnormal lesion in three cases among these 6 cases. No definite signal intensity difference between tumor and pharyngeal mucosa was shown on both T1 and T2 weighted images. But the normal pharyngeal mucosa had demonstrated higher intensity than tumor with Gd-DTPA administration. So the enhanced nasopharyngeal MR imaging made the clear intensity difference between tumor and muscle tissue. It was the conclusion that MR imaging was superior to X-CT in detecting small nasopharyngeal tumor.

Adult↗
PubMed1991

Prognostic factors for local control in nasopharyngeal cancer (NPC): analysis by multivariate proportional hazard models.

Despite the development of meticulous radiation therapy techniques, the local control of the nasopharyngeal cancer (NPC) remains unsatisfactory. We examined retrospectively the clinicopathologic factors which have impact upon local recurrence-free survival (LRFS) of the 67 patients with NPC who had been irradiated greater than or equal to 40 Gy with curative intent from 1975 through 1988. Three-year LRFS rate was 63%. T stage, histology, the presence of accompanying lymphocytic infiltration, and the properness of radiation therapy had influence upon LRFS with a statistical significance. Multivariate proportional hazard models showed that T stage and pathology retained significance. Radiation therapy properness emerged as a third factor when only the patients irradiated greater than or equal to 60 Gy were included in the analysis. From these results, three groups with low, moderate, and high risk of shortened LRFS could be separated. This risk classification could contribute to the stratification criteria of future study for the improvement of local control by new modalities.

Adult↗
PubMed1991

Nonneoplastic enhancing lesions mimicking intracanalicular acoustic neuroma on gadolinium-enhanced MR images.

The authors describe five patients with nonneoplastic lesions of the facial and/or vestibulocochlear nerves that demonstrated focal enhancement within the internal auditory canal on magnetic resonance (MR) images. MR and surgical findings for four patients with unilateral sensorineural hearing loss and one with Ramsay Hunt syndrome were reviewed. Three patients with hearing loss underwent surgical exploration and decompression of the internal auditory canal. The MR findings in all four patients with hearing loss were similar: Focal enhancement of the internal auditory canal was depicted on postcontrast T1-weighted images. Nonneoplastic lesions of the seventh and eighth cranial nerves may show focal enhancement on MR images, which mimics the appearance of a small intracanalicular neuroma. This potential for misdiagnosis may have important therapeutic implications.

Cranial Nerve Diseases↗
PubMed1991

Heart rate responses to body tilt during spinal anesthesia.

To evaluate whether low-pressure baroreceptors located in the right atrium could affect the heart rate (HR) during spinal anesthesia, the authors determined the effects of right atrial pressure changes associated with body tilt on HR in 40 unpremedicated patients. Ten-degree head-up body tilt produced significant increases in HR of 6 +/- 1 and 6 +/- 1 beats/min (mean +/- SE, P less than 0.01) and significant decreases in systolic arterial pressure of 2.8 +/- 0.9 and 6.6 +/- 1.7 mm Hg (P less than 0.01) during low (T-10 +/- 0.2, n = 20) and high (T-4 +/- 0.2, n = 20) analgesic levels of tetracaine spinal anesthesia, respectively. Ten-degree head-down body tilt caused significant decreases in HR without significant changes in systolic arterial pressure during spinal anesthesia. The reflex HR responses to body tilt were similar between low and high levels of spinal anesthesia and were preserved after administration of sedatives. The magnitudes of changes in right atrial pressure associated with body tilt were similar during spinal anesthesia and after sedation. These findings suggest that HR responses to head-up body tilt are mediated mainly by arterial baroreceptors even in the face of decreased venous return during low or high levels of spinal anesthesia and that light sedation does not impair this reflex HR response.

Adult↗
PubMed1991

Nd: YAG interstitial laser phototherapy guided by magnetic resonance imaging in an ex vivo model: dosimetry of laser-MR-tissue interaction.

Interstitial laser phototherapy (ILP) is a promising technique in which laser energy is delivered percutaneously to various depths of tumors. This technique will become clinically useful only when efficient, sensitive, and noninvasive monitoring systems are developed. In this study, the spatial distribution of ILP in bovine liver tissue, induced by a Nd: YAG laser with an interstitial sapphire-frosted contact probe, was evaluated by magnetic resonance imaging (MRI). Tissue was exposed to three energy densities of the Nd:YAG laser by a reproducible method of dosimetry. Thermal profiles were measured with a probe inserted 5 mm from the laser tip. T1-weighted magnetic resonance images were taken after the laser exposure. Tissue specimens were then evaluated for standard quantification of laser-induced damages. A linear correlation between the level of laser energy, induced temperature change, lesion size on T1 magnetic resonance image, and volume of histological damage was observed. Further improvement of this technique of dosimetry in an in vivo model should allow the development of software for MRI which will correlate the above parameters and render this technique of ILP clinically useful.

Animals↗
PubMed1990

Attenuated sympathetic tone augments nitrous oxide-induced myocardial depression during high-dose fentanyl anaesthesia in dogs.

The purpose of this study was to determine whether centrally mediated sympathetic tone exerts compensatory effects on nitrous oxide-induced myocardial depression during high-dose fentanyl anaesthesia. The cardiovascular responses to 60 minutes of nitrous oxide administration after fentanyl, 100 micrograms.kg-1, were examined in 18 dogs with or without autonomic blockade induced by hexamethonium. Decreases of cardiac output and left ventricular stroke work were significantly greater in dogs with autonomic blockade (n = 9) by about 20 per cent of baseline values than in dogs without autonomic blockade (n = 9) at 30, 45, and 60 min. Similarly, left ventricular dP/dt was reduced more in dogs with autonomic blockade than in dogs without autonomic blockade, but this difference was only significant at the 60-min period. It is concluded that the sympathetic nervous system provides partial compensation for myocardial depression induced by nitrous oxide in the presence of high-dose fentanyl, suggesting that large doses of fentanyl do not ablate the centrally mediated sympathomimetic effects of nitrous oxide.

Analysis of Variance↗
PubMed1990

Isolation of bacterial strains, which hydrolyze glycyrrhizin and produce glycyrrhezic acid, from soil.

We isolated eight bacterial strains which could hydrolyze glycyrrhizin to glycyrrhezic acid. The bacterial strains were identified as three strains of Pseudomonas saccharophila, two of Plesiomonas sp., one of Pseudomonas stutzeri, one of Klebsiella pneumoniae subsp. ozaenae and one of Kluyvera ascorbata. Their capacity for the conversion of glycyrrhizin to glycyrrhezic acid was assayed by high performance liquid chromatography. P. saccharophila 11 was the most effective among the eight strains. Then, beta-glucuronidase, which is responsible for hydrolysis of glycyrrhizin, activity was assayed with p-nitrophenyl-beta-D-glucuronide as a substrate. P. saccharophila 11 showed the highest beta-glucuronidase activity among the eight strains. This indicates that P. saccharophila 11 may be useful for production of glycyrrhezic acid from glycyrrhizin by industrial fermentation.

Anti-Bacterial Agents↗
PubMed1990

[Evaluation of image quality and lesion detectability on I-123 IMP brain SPECT].

Influence of image quality on lesion detectability in I-123 IMP brain SPECT was discussed in forty-two cases with various cerebrovascular disorders. Fifty nine lesions, which were considered to show decreased uptake of I-123 IMP, were analyzed in this study. In all cases, SPECT examinations were started within 30 minutes after intravenous administration of 3 mCi of I-123 IMP. To determine the lesion detectability, fourteen radiologists from nine hospitals were gathered and film reading was carried out. To classify the image quality into valuable or not, findings of five points on SPECT image were visually evaluated; 1) uniformity of cortex accumulation, 2) separation of bilateral visual cortices, 3) density of white matter, 4) separation between basal ganglion and thalamus, 5) density of basal ganglion and thalamus. Mean lesion detections were 10.3/14 for the lesions of cerebral cortex, 9 for cerebellum, 3.58 for white matter and 3.22 for basal ganglion and thalamus, respectively. The detectability was certainly influenced by the image quality in the lesion of basal ganglion and thalamus, white matter and single lobe of cerebral cortex. We concluded that detection of small lesions and deep lesions with I-123 IMP SPECT was dependent on the image quality and the proposed classification of I-123 IMP SPECT image was useful for evaluating image quality from the points of view of the lesion detectability.

Adolescent↗
PubMed1990

[A case of subacute cerebral infarction demonstrating hyperemia and crossed cerebellar diaschisis in I-123 IMP SPECT].

SPECT with N-isopropyl-p-[I-123]iodoamphetamine were performed in a 81-year-old man with cerebral infarction. In the subacute phase, the radioactivity was increased in the infarct area where fogging effect and remarkable contrast enhancement was demonstrated in X-ray CT. The contralateral cerebellar hemisphere showed reduced activity due to crossed cerebellar diaschisis (CCD). In the chronic phase, the decrement of the activity in the infarct was observed. Increased activity in the subacute phase was thought to reflect the hyperemia in the infarct, while CCD suggested the decreased metabolic activity in the lesion. The coexistence of the hyperemia and the CCD indicates flow and metabolic uncoupling, which means "luxury perfusion". This case was also thought to demonstrate atypical findings of CCD in SPECT imaging.

Aged↗
PubMed1990

[A case of pulmonary embolism diagnosed by 111In labeled platelet scintigraphy].

Although the role of 111In platelet scintigraphy is established in the diagnosis of deep vein thrombosis, its indication in pulmonary embolism remains uncertain. We performed platelet scintigraphy in a patient with recurrent pulmonary thromboembolism, which revealed abnormal accumulation in the left hilar region. Pulmonary perfusion scintigraphy performed at the same time did not show perfusion defect. However, pulmonary angiography and thromboembolectomy demonstrated recurrent embolus in the hilus. This suggested that platelet aggregation in the left hilus shown by platelet scintigraphy was indeed related with recurrence of pulmonary embolism, and platelet scintigraphy is useful in detecting new development of thrombus in patient with recurrent pulmonary thromboembolism.

Blood Platelets↗
PubMed1990

[Evaluation of pontine visualization with single photon emission computed tomography using N-isopropyl-p-(I-123)iodoamphetamine in normal and pathological cases].

Pontine visualization with single photon emission computed tomography (SPECT) using N-isopropyl-p-[I-123]iodoamphetamine (I-123 IMP) was evaluated in 99 cases including 46 cases of brain infarction, 25 of other cerebrovascular disorders and 28 of brain tumor and in 19 normal subjects. In each case, SPECT using a rotating gamma camera was started at 30 minutes after intravenous administration of 111 MBq of I-123 IMP. Transverse images were reconstructed parallel to the cantho-meatal line and displayed on films. Pontine visualization was visually classified into three grades: high radioactive accumulation confined to the pons with clear contour (Grade 3), faint accumulation with indistinct contour in the pontine region (Grade 1), the pontine accumulation was identified but its activity was less significant (Grade 2). The results showed that grade of the pontine accumulation was lower in pathological cases compared to normal subjects. Six cases with brain stem lesion demonstrated pontine accumulation of grade 1 in 4 case and of grade 2 in 2 cases. Lower grade was also revealed in 29 cases with crossed cerebellar diaschisis (CCD). No significant correlation was observed between classified grade of pontine accumulation and maximum counts of reconstructed images. We concluded that SPECT could detect brain stem lesions and that lower accumulation in pons with CCD positive cases was thought to partially reflect the reduced blood flow and metabolism in the pontine nuclei.

Adolescent↗
PubMed1989

Proliferation and responsiveness to estrogen of human endometrial cancer cells under serum-free culture conditions.

Studies of hormonal growth regulation in cultured human endometrial cancer cells are limited by the requirement of exogenous growth factors, usually supplied by addition of serum. The present report provides evidence that estradiol can stimulate proliferation of endometrial cancer cells of the Ishikawa line in the absence of serum or added growth factors. Mitogenic effects of estrogen were demonstrated in two different experimental systems, in cells attached to the substratum of mammalian tissue culture dishes, and in cells forming colonies in soft agar under anchorage-independent conditions. Addition of estradiol to a mixture of serum-free, phenol red-free Dulbecco's minimal essential medium and Ham's F-12 medium, supplemented with L-glutamine and 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid [basal medium: (BM)] significantly increased the proliferation of cells attached to culture dishes. Dose-response experiments revealed maximal estradiol stimulation at 10 nM; significant responses were also observed at 1 nM and at 100 nM concentrations. The mitogenic effect of 10 nM estradiol was comparable to that of 1% charcoal-treated fetal bovine serum and the two effects were additive. The presence of estradiol in serum-free BM resulted in a shortening of the doubling time of exponentially proliferating cells from 38 to 29 h. From the labeling index, measured after exposure to a pulse of [3H]thymidine, and from the mitotic index, both determined in exponentially proliferating cells, the lengths of the S and M phases were calculated to be 11 and 1 h, respectively. From these data it was estimated that estradiol shortened the G1 phase by approximately 40%, from 22 to 13 h. Estradiol doubled the colony formation efficiency of cells plated in BM containing 0.3% agar in the absence of serum as well as in the presence of 1% charcoal-treated fetal bovine serum. The stimulation of colony formation by estradiol was influenced by medium components, since no effects were observed in minimal essential medium. The colony formation efficiency was positively related to the serum concentrations and remained significantly lower in minimal essential medium than in BM at comparable serum levels. The observed positive relationship between colony formation efficiency and cell densities at plating suggests a cooperative mitogenic effect, likely due to autocrine and paracrine action of secreted growth factors. These results define a model to evaluate hormonal growth regulation mediated by autocrine mitogens in human endometrial cancer cells in the absence of interfering exogenous growth factors.(ABSTRACT TRUNCATED AT 400 WORDS)

Cell Aggregation↗
PubMed1989

Stimulatory effects of 4-hydroxytamoxifen on proliferation of human endometrial adenocarcinoma cells (Ishikawa line).

The effects of trans-4-hydroxytamoxifen (OHTam) on proliferation of cells of the Ishikawa human endometrial adenocarcinoma line were studied under serum-free, phenol red-free conditions and compared to those of estradiol. The addition of OHTam (1 microM) to basal medium (BM), consisting of equal parts of Dulbecco's modified Eagle's medium and Ham's F-12 with additional glutamine and 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid, resulted in significant increases in cell numbers relative to controls. These effects were even greater than those obtained with estradiol (10 nM-1 microM) or 1% charcoal-treated fetal bovine serum (ctFBS). Addition of 1% ctFBS to BM containing 1 microM OHTam further increased cell numbers whereas addition of estradiol (10 nM) did not do so. The stimulation of growth was positively correlated with OHTam concentrations in the range of 10 nM to 1 microM. Dissociation of estradiol and OHTam proliferative effects was observed in a variant of Ishikawa cells in which estradiol did not increase proliferation while OHTam had a strong stimulatory effect. The growth-promoting effects of OHTam were also observed in BM containing 5% or 15% ctFBS. In contrast, in parallel experiments in which BM was replaced by minimal essential medium (Eagle's) with Earle's salts, OHTam (1 microM) did not stimulate proliferation under these conditions and acted as an antiestrogen, inhibiting the proliferative effects of estradiol. These results illustrate marked effects of medium composition on proliferation and antiestrogenic actions of OHTam. Alkaline phosphatase activity was strongly stimulated by estradiol (10 nM) but only very weakly affected by OHTam (1 microM); at these concentrations, OHTam inhibited the effect of estradiol, both in serum-free BM and in minimal essential medium plus 15% ctFBS, demonstrating dissociation in its actions on proliferation and on enzymatic activity. These findings suggest that OHTam may stimulate the proliferation of particular clones of endometrial cancer cells in human tumors. They also suggest that OHTam can exert effects not mediated by the estrogen receptor system, or form OHTam-estrogen receptor agonistic complexes unlike those resulting from estradiol-estrogen receptor interactions. Clearly, Ishikawa cells provide a useful model to investigate mechanisms of action of antiestrogens.

Adenocarcinoma↗
PubMed1989

[Study of multiregression analysis on NK activities and related clinical factors in patients with head and neck neoplasms].

NK activity in patients with head and neck neoplasms treated with radiation and chemotherapeutics was studied on the influence of 19 factors by using the method of multiregression analysis. Of these factors, BUN, WBC, the size of radiation portal, chemotherapy, radiation doses, total protein (T.P.), age and GOT were significantly influenced on the fluctuation of NK activity (p less than 0.05). In the studies of the size of radiation portal and its doses, NK activity showed a tendency to increase with radiation dose in small size of radiation portal and a tendency to reduce in large size of it.

Adult↗
PubMed1989

Effects of serine and glycine on proliferation of an Ishikawa cell variant.

The proliferation of cells on an Ishikawa human endometrial adenocarcinoma line variant (Ishikawa-Var I) is markedly influenced by the medium used to culture them, viz. MEM vs BM (basal medium; DMEM/Ham's F12, 1/1, with additional glutamine and HETES), under serum-free conditions. Components of BM which are not present in MEM were systematically tested in order to identify those that might account for these differences. Cells were cultured for various periods of time, up to 8 days, in serum-free MEM to which the components to be tested were added. Cell population densities were evaluated using a fluorometric DNA assay when the cells were grown in multiwell plates, or by cell counting when the cells were cultured in plastic dishes. It was found that addition to MEM of a mixture of the amino acids that this medium lacks, significantly increased cell density. By testing individual amino acids at the concentrations present in BM, it could be demonstrated that addition of serine alone was sufficient to obtain the densities achieved with BM. Glycine, a metabolic precursor of serine, had a similar but smaller effect. None of the other missing compounds of BM was effective. Effects of serine on DNA synthesis were also estimated by measuring incorporation of [3H]thymidine for 1 h after a 24 h culture period in MEM. The effect of serine was similar and additive to that of 1% charcoal-treated fetal bovine serum. A serine concentration dependence studied either with this method or measuring DNA/well after 8 days in culture showed detectable effects at 0.005 mM concentration and maximal responses at about 0.025 mM. These findings are of potential importance in studies on regulatory mechanisms of cell proliferation. A possibility to be explored, for instance, is that serine added to the medium increases intracellular phosphatidylserine concentrations leading to increases in the activity of protein kinase C, a stimulator of cell proliferation in some systems.

Adenocarcinoma↗
PubMed1989

[A clinical study of a multiregression analysis on the NK activity and related clinical factors in patients with lung cancer].

Using 24 lung cancer patients (20 males and 4 females) who had received radiotherapy, a multivariate analysis has been performed in relation to 19 factors suspected of exerting an effect on natural killer (NK) cell activity. As influencing factors, two factors of the disease, the stage (p less than 0.05) and the leukocyte count (p less than 0.08), were calculated to be significant. In the univariate analysis, the NK activity was found to be significantly low (p less than 0.05) when the leukocyte count was 7,000 or higher. In addition, patients who had died during the course of radiotherapy showed an NK activity which was significantly lower (p less than 0.05) than the activity manifested in both the disease-free patients and the relapsed progressive disease patients. Moreover, the patients with a PS of 40% or less had a significantly lower NK activity than the patients with a PS of 50% or more, though no correlation was found between the NK activity and the disease stage. In the use of this radiotherapy, the NK activity was found to be more strongly influenced by the size of the irradiated field than by the irradiated dose.

Adult↗
PubMed1989

[Intrathecal clonidine--how does it work in spinal fentanyl analgesia in rats?].

The effects of intrathecal clonidine on spinal fentanyl analgesia were studied by the hot-plate test (52.0 degrees C) in rats. Clonidine (5 micrograms) and/or fentanyl (5 micrograms) were administered alone or combined in volume of 10 microliters through a chronically-implanted polyethylene catheter (PE-10) whose tip was near the lumbar enlargement of the spinal cord. Injections were done repeatedly every two or three days to determine the time course of thermal analgesia. Results were as follows; 1) Intrathecal clonidine (n = 5) produced no thermal analgesia. 2) Intrathecal fentanyl (n = 10) produced a profound thermal analgesia which was attenuated markedly by the repeated injections in six rats before the 9th injection. 3) Two out of six fentanyl tolerated rats responded with remarkable increases in thermal thresholds following the intrathecal clonidine with fentanyl. 4) Rats which were administered with both clonidine and fentanyl from the 1st injection (n = 9) responded with a extended prolongation of the escape latency, compared with the rats which received fentanyl only. In this group, the tolerance developed in only three animals by the 9th injection. In conclusion, combined intrathecal administration of clonidine with fentanyl potentiated the analgesic effect of fentanyl and then definitely suppressed the tolerance formation even if a small dose of clonidine which produces no analgesic effect was used. These results suggest that intrathecal or epidural administration of clonidine with narcotics might be useful in managing intractable pain.

Adaptation, Physiological↗