Search PubMed⌕ Search

Biomedical subjects

Y Anzai

Publications and source records attributed to Y Anzai.

At least 19 recordsLinked to original sources
PubMed1995

Thoracic epidural clonidine and morphine for postoperative pain relief.

This study was undertaken to evaluate the potentiation of the postoperative analgesic effect of thoracic epidural morphine by coadministration of thoracic epidural clonidine in a randomized double-blinded design. Twenty patients underwent radical gastrectomy under combined general anaesthesia (enflurane and nitrous oxide/oxygen) and epidural anaesthesia with local anaesthetics. They received a thoracic epidural bolus injection of either 0.05 mg.kg-1 morphine plus 3 micrograms.kg-1 clonidine (M+C group; n = 10) or 0.05 mg.kg-1 morphine alone (M group; n = 10) immediately before completion of surgery. All patients received iv morphine via patient-controlled analgesia (PCA) equipment for 24 hr postoperative period, and the PCA iv consumption of morphine was the primary variable of efficacy of the analgesic regimen. In addition, data analyses included mean arterial blood pressure, heart rate, respiratory rate, arterial blood gas measurement, sedation score, and visual analogue pain scale score (VAS). The cumulative number of iv morphine injections via PCA was less in the M+C group than in the M group at each hour for 24 hr postoperative period (P < 0.05), while the numbers of PCA morphine injections per hour beyond nine hours after surgery were higher in the M group than in the M+C group (P < 0.05). Sedation score was higher, and VAS and mean blood pressure were lower in the M+C group only at one hour after surgery compared with the M group. We conclude that the combined single thoracic epidural administration of morphine plus clonidine produces a more potent and longer lasting analgesia than does morphine alone.

Analgesia, Epidural↗
PubMed1995

Sheep red blood cell instillation at palatine tonsil effectively induces specific IgA class antibody in saliva in rabbits.

We have shown that the palatine tonsil effectively incorporates exogenous foreign substances instilled at its surface. It is not clear whether antigen-specific IgA can be induced by the instillation. Sheep red blood cells (SRBC) were instilled at the palatine tonsil every three days as the antigen, and the agglutination titer of specific IgA in saliva was examined. Nasal or intragastric administration, which have been shown to induce specific antibody in saliva, were done as control experiments. Anti-SRBC antibody in saliva from the tonsillar instillation group was detected in the second week, and the agglutination titer reached a maximum in the 6th week after instillation. The maximum titers in the tonsillar instillation group and nasal administration group were 16 (P < 0.01, n = 7) and 4 times (P < 0.01, n = 7) higher, respectively, than that in the intragastric administration group. In the tonsillar instillation group, the number of specific antibody- producing cells per 10(5) lymphocytes was the highest in the parotid glands compared with the lymphoid tissues such as the retropharyngeal lymph nodes, nasal mucosa, mesenteric lymph nodes, Peyer's patches, cervical lymph nodes, palatine tonsil and spleen. In the nasal administration group, the number of lymphocytes was the highest in the nasal mucosa. The results indicate that tonsillar instillation was more effective than nasal administration in inducing specific iIgA in saliva.

Administration, Intranasal↗
PubMed1995

Hyperacute thermal lesions: MR imaging evaluation of development in the brain.

PURPOSE: To determine the natural time course of development of hyperacute thermal lesions in the brain. MATERIALS AND METHODS: Ten interstitial lesions were created in five rabbit brains with a radio-frequency probe; an electrode-tip temperature of 80 degrees C was maintained for 60 seconds. Continuous fast spin-echo magnetic resonance (MR) imaging was used to follow lesion development for a minimum of 30 minutes. Temporal variations in lesion size and signal intensity were examined. Findings in final images were correlated with histologic findings. RESULTS: Images demonstrated a focal hyperintense zone, which developed into an expanding ring of edema surrounding a necrotic center in about 10 minutes. Quantitative analysis revealed a 23% +/- 6 (standard deviation) increase in average signal intensity of the edema layer and a 152% +/- 41 increase in overall lesion size. CONCLUSION: Full development of a thermal lesion is delayed for a period of minutes. Clinical implications of this effect should be considered when MR imaging-guided thermal ablation is performed.

Animals↗
PubMed1995

Early postoperative appearance of radiofrequency lesions on magnetic resonance imaging.

Eleven patients who underwent stereotactic radiofrequency lesions in the central nervous system had magnetic resonance imaging follow-up within 72 hours of surgery to determine the early appearance of their lesions. Eight patients with severe tremor, one with chronic pain, and two with dystonia were analyzed. There were six female patients and five male patients, age 7 to 75 years (mean +/- standard deviation = 42 +/- 21). Magnetic resonance imaging was performed postoperatively at 32 +/- 25 hours (range, 3-72). Postoperative T1-weighted spin echo images demonstrated foci of iso- to hyperintensity surrounded by an edge of hypointensity, and corresponding T2-weighted images showed a lesion with three concentric zones consisting of inner hypointense, middle hyperintense, and outer hypointense zones. Gadolinium increased T1-weighted image lesion visibility, and a ring of enhancement around the zone of hypointensity was observed. Lesions could be seen as early as 3 hours after surgery. The lesions were best shown on gadolinium-enhanced T1-weighted images and on T2-weighted images. The edema surrounding the lesion increased over time, up to the 72 hours studied. These data provide important information on the development of lesion appearance, which may be applied in the development of real-time magnetic resonance imaging monitoring of radiofrequency lesion formation. This technique associated with electrophysiological response and the real-time visualization of the anatomic correlation of the probe may allow for a very precise and selected lesion in the central nervous system for the treatment of functional disorders and brain tumors.

Adolescent↗
PubMed1995

Evaluation of cervical lymph node metastases in squamous cell carcinoma of the head and neck.

Although computed tomography and magnetic resonance imaging have contributed to the ability to identify metastatic disease in head and neck cancer, inadequacies in evaluating lymphadenopathy still exist. This study was undertaken to estimate the accuracy of radiological criteria used to detect cervical lymph node metastases. The morphological characteristics of 957 lymph nodes from 36 neck dissections from patients with squamous cell cancer were examined microscopically. A large number of malignant nodes were found to have diameters of less than 10 mm. Extranodal spread also occurred in a substantial percentage of smaller nodes. Because the present radiological criteria for assessing cervical lymph node status are based largely on size, findings indicate major limitations in the capabilities of detecting metastatic disease. New modalities to improve the staging of head and neck cancer are discussed.

Carcinoma, Squamous Cell↗
PubMed1995

Interventional computed tomography and MR imaging in the head and neck.

Many modern surgical techniques have been developed to provide exposure or visualization of the surgical field to perform definitive treatment. The actual therapeutic part of surgery is often a small fraction of the procedure. In obtaining exposure, however, morbidity can ensue. This has led to newer techniques that use minimally invasive treatments, thus substantially decreasing overall morbidity and patient costs. By providing physicians with visualization alternatives, MR imaging and computed tomography, when combined with a therapeutic procedure, can reduce the morbidity of surgery.

Biopsy, Needle↗
PubMed1994

Initial clinical experience with dextran-coated superparamagnetic iron oxide for detection of lymph node metastases in patients with head and neck cancer.

PURPOSE: To investigate the efficacy of magnetic resonance (MR) imaging with dextran-coated superparamagnetic iron oxide in the differentiation of metastatic and benign nodes in patients with head and neck cancer. MATERIALS AND METHODS: MR imaging was performed before and after intravenous administration of iron oxide in 12 patients. Ninety-one pathologically proved nodes were visually analyzed, and 66 lymph nodes were quantitatively analyzed by measuring signal intensity in visually selected regions of interest. RESULTS: Forty of 42 histologically proved metastatic nodes and 41 of 49 benign nodes were detected, yielding 95% sensitivity and 84% specificity. The signal intensity ratio of benign nodes was substantially lower than that of metastatic nodes, indicating better differentiation of metastatic and benign nodes. Furthermore, 13 of 14 normal-sized nodes were detected. CONCLUSION: MR imaging with iron oxide can enable specific differentiation of metastatic and benign nodes in patients with head and neck cancer. This agent may potentially enhance the detection of metastatic lymph nodes and deserves further investigation.

Adult↗
PubMed1994

Dextran-coated superparamagnetic iron oxide, an MR contrast agent for assessing lymph nodes in the head and neck.

PURPOSE: To investigate dextran-coated superparamagnetic iron oxide particles (BMS 180549) as an MR contrast agent for assessing lymph nodes. METHODS: Five different doses ranging from 0.3 to 1.7 mg Fe/kg were evaluated in five healthy human male subjects as part of a phase 1 clinical study. T1-, T2-, and proton density-weighted spin-echo images as well as multiplanar gradient-echo and spoiled gradient-echo images were acquired before and 1 hour, 4 hours, and 24 hours after contrast administration. Image analysis was performed with visually selected regions of interest. Signal intensities were measured for neck lymph nodes and the adjacent muscle. Enhancement effects were evaluated as a function of dose, imaging time after contrast administration, and MR pulse sequence. RESULTS: The iron oxide particles were phagocytized by macrophages within the normal functioning lymph nodes, resulting in a dramatic decrease in signal intensity because of magnetic susceptibility effects. T2*-weighted gradient echo and T2-weighted spin echo showed significant decrease in the signal intensity of normal lymph nodes at 24 hours after contrast injection at a dose of 1.7 mg Fe/kg. No significant changes in lymph node signal intensity on T1-weighted spin-echo images were noted at any dose or imaging time point. CONCLUSIONS: This preliminary clinical evaluation demonstrates intravenous delivery of an iron-based contrast agent, resulting in negative enhancement of normal lymph nodes.

Adult↗
PubMed1992

Comparison of Indium-111-labeled leukocyte scintigraphy and Technetium-99m joint scintigraphy in rheumatoid arthritis and osteoarthritis.

This study was undertaken to evaluate the use of Indium-111-labeled leukocyte (111In-WBC) imaging compared with Technetium-99m pertechnetate (99mTcO4-) imaging in 19 patients with rheumatoid arthritis (RA) and 8 with osteoarthritis. Knee and wrist joints were evaluated for both radionuclides. The results indicated a good correlation of the clinical assessment of pain and swelling with joint uptake ratio (JUR) between 111In-WBC and 99mTcO4- in RA and osteoarthritis patients. We observed a discrepancy in both imagings in "burned out" cases. It was concluded that a JUR of 111In-WBC could distinguish active RA from inactive RA or osteoarthritis at a value of 1.15 and that the use of 111In-WBC was a more reliable procedure than 99mTcO4-.

Adult↗
PubMed1992

Effects of transforming growth factors and regulation of their mRNA levels in two human endometrial adenocarcinoma cell lines.

The effects of the transforming growth factor-beta 1 (TGF-beta 1) and epidermal growth factor (EGF) on the growth of cells from 2 endometrial cancer lines, Ishikawa and HEC-50 were evaluated by measuring rates of DNA synthesis and changes in cell numbers during culture. EGF at 17 and 1.7 nM concentrations consistently enhanced HEC-50 cell proliferation. TGF-beta 1 inhibited Ishikawa cell proliferation but, unexpectedly for epithelium-derived cells, stimulated HEC-50 cell growth. This effect is of interest as it indicates that endometrial cells can acquire an altered responsiveness to a growth inhibitor during the process of malignant transformation. Northern blot analyses showed expression of TGF-alpha, TGF-beta 1 and EGF receptors mRNA in both cell lines. Neither estradiol (E2) nor 4-hydroxytamoxifen (OHTam) affected mRNA levels for either TGF-alpha or TGF-beta in HEC-50 cells, a line unresponsive to E2 for proliferation. In Ishikawa cells, previously shown to respond to both E2 and OHTam by increasing proliferation rates, E2 increased TGF-alpha mRNA and reduced TGF-beta mRNA levels. OHTam lowered the levels of both mRNA species, although the effect was greater on TGF-beta than TGF-alpha mRNA. These data are consistent with, but do not prove, the existence of a possible autocrine regulation by TGF-alpha and TGF-beta of human cancer cell proliferation, which might be under E2 influence in Ishikawa cells.

Adenocarcinoma↗
PubMed1992

Three-dimensional CT scan reconstruction for the assessment of congenital aural atresia.

Major advances in medical computer graphics workstations have provided the capability to produce high quality three-dimensional image reconstructions from conventional thin-section computerized tomography (CT) scans with the ability to observe the imaged structure from any angle, with views and dimensions that are comparable to actual dissections. We have applied this technique to the temporal bone to assess congenital aural atresia in surgical planning for hearing reconstruction in six patients. The digital information produced by thin-section CT scanning allowed for the re-creation of multiplanar reformatted, shaded surface, and volumetric images. With this technique the surface landmarks of the temporal bone were readily visualized, the configuration of the atretic plate and middle ear in relation to the tegmen and glenoid fossa could be precisely assessed and the structure of the ossicular mass was easily analyzed. Most significantly, the facial nerve could be accurately and easily envisioned in its entire intratemporal course. Three-dimensional imaging is a highly desirable means for observing CT scan data to facilitate the surgical planning for correction of congenital aural atresia.

Adolescent↗
PubMed1991

Transforming growth factor gene expression in human endometrial adenocarcinoma cells: regulation by progestins.

In an attempt to understand the antiproliferative effects of progestins in endometrial cancer, we have examined the effects of the potent progestin, medroxyprogesterone acetate (MPA), on the cell proliferation and the expression of transforming growth factor (TGF) alpha and beta genes in human endometrial adenocarcinoma cell lines. The two cell lines used were Ishikawa, var 1, and HEC-50. In addition, the effects of exogenous TGF-alpha and anti-epidermal growth factor (EGF) receptor monoclonal antibody on cell proliferation were determined. Incubation of both cell lines with MPA resulted in a time- and dose-dependent inhibition of cell proliferation. Half-maximal growth inhibition was observed at 0.6 nM. In Ishikawa cells, the relative abundance of TGF-alpha was significantly reduced by MPA. A significant decrease in TGF-alpha mRNA was apparent 6 h after exposure to MPA and a further decrease was seen 12-24 h after addition of the progestin. The concentration of TGF-alpha immunoreactivity in conditioned medium of MPA-treated cells was also significantly reduced compared to control cultures. MPA had no effect on TGF-alpha expression by HEC-50 cells. EGF mRNA was not detected by Northern blot analysis in either cell type. MPA had no significant effect on EGF receptor mRNA abundance but resulted in a small increase in EGF receptor number in Ishikawa cells. Anti-EGF receptor monoclonal antibody (0.6-6 nM) inhibited Ishikawa cell growth but had no effect on HEC-50 cell proliferation. Exogenous TGF-alpha stimulated proliferation of both cell lines, but Ishikawa cells were significantly more sensitive to exogenous TGF-alpha than HEC-50 cells. Furthermore, TGF-alpha could reverse the growth inhibitory effects of MPA on Ishikawa cells. A decrease in TGF-beta mRNA abundance was also observed in MPA-treated Ishikawa and HEC-50 cells. This effect was of small magnitude, variable, and only observed after prolonged exposure to MPA. These observations are consistent with the hypothesis that the antiproliferative effects of progestins on Ishikawa cells are mediated by decreased expression and autocrine action of TGF-alpha. Since similar growth inhibition is also seen in the HEC-50 cells in which progestins have no effect on TGF-alpha expression, additional mechanisms are likely to be involved in the antiproliferative effects of progestins in human endometrial cancer.

Antineoplastic Agents↗
PubMed1991

Isolation and analysis of the mouse genomic sequence encoding Cu(2+)-Zn2+ superoxide dismutase.

Cu(2+)-Zn2+ superoxide dismutase (SOD-1) is a ubiquitously synthesized eukaryotic enzyme with a variety of important roles in mammalian development and physiology. With the goal of better understanding the structure and regulation of this gene, we have cloned and analyzed the genomic structure of the mouse SOD-1 gene. The murine sequence has an intron:exon organization very similar to that of the human gene, though significant diversion was observed in the promoter and 3' regions. These differences account for the observation that only a single transcript for SOD-1 is seen in mouse cells, while two transcripts are derived from the human gene. The cloning of mouse SOD-1 should allow elucidation of the regulatory characteristics of this element, as well as new and informative genetic engineering experiments.

Amino Acid Sequence↗
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↗