Safranin O counter-staining enhances the counting of beta-galactosidase-expressing cells.
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Cell Count↗
Biomedical subjects
K C Ho
Publications and source records attributed to K C Ho.
Anatomic relationship of the oculomotor nuclear complex and medial longitudinal fasciculus in the midbrain.
PURPOSE: To compare the MR characteristics of the oculomotor nucleus with its appearance on anatomic images. METHODS: Specimens of cadaveric brains were imaged in a 3.0-T MR imager equipped with a 3.0-cm solenoid coil. The specimens were sectioned, stained, and examined histologically. On anatomic sections, the oculomotor nuclei, medial longitudinal fasciculus, red nuclei, and oculomotor nerve were identified. The MR images were then compared with the anatomic sections. RESULTS: The oculomotor nuclei, medial longitudinal fasciculus, red nuclei, and oculomotor nerve could be identified on MR images by their size, shape, signal intensity, and location. CONCLUSION: MR images show the anatomic relationship of the oculomotor nerve complex, medial longitudinal fasciculus, and related structures in the brain stem.
Abducens Nerve↗
Effect of degeneration of the intervertebral disk on the process of diffusion.
PURPOSE: To test the hypothesis that diffusion of contrast medium into the intervertebral disk is affected by the integrity of the nucleus pulposus and annulus fibrosus. METHODS: In canine intervertebral disks, defects were made in the annulus fibrosus and nuclear material was removed from the disk with a nucleotome. MR imaging was performed with intravenous contrast medium at 15, 30, 60, and 90 days after the procedure. The diffusion of contrast medium in the intervertebral disk was studied by visual inspection and by measuring changes in signal intensity. The intervertebral disk were classified at each MR study as normal or abnormal on the basis of the signal intensity on T2-weighted images. RESULTS: In untreated disks after intravenous injection of contrast medium, a band of increased signal intensity was observed near the endplates that became wider with time and approached the center of the disk. In six of the 12 treated disks, the band of increased signal intensity was visibly diminished or less discrete compared with that in the control disks. Weeks later, these treated disks showed diminished signal intensity on T2-weighted images and bulging of the annulus fibrosus. CONCLUSIONS: Intervertebral disks with defects in the annulus fibrosus and reduced cartilage content were characterized by abnormal diffusion of contrast medium into the disk, and changes characteristic of early disk degeneration were detected subsequently.
Animals↗
Spontaneous remission in acute myelogenous leukemia: a case report.
A 62-year-old woman with hypocellular acute myelogenous leukemia experienced spontaneous remission after repeated episodes of severe infections. Transient surge of profuse blasts in the peripheral blood was observed prior to the occurrence of spontaneous remission. The duration of the spontaneous remission was relatively short, and the disease relapsed five months later. A second complete remission was achieved after chemotherapy with low-dose cytosine arabinoside. The patient finally died of relapsed leukemia after a second remission of three year duration. Possible mechanisms implicated in the occurrence of spontaneous remission in this patient are discussed.
Antimetabolites, Antineoplastic↗
Malignant lymphomas of sinonasal region, including cases of polymorphic reticulosis: a retrospective clinicopathologic analysis of 34 cases.
BACKGROUND: Lymphomas occurring in nasal cavities and paranasal sinuses are uncommon neoplasms in Western, but are reported to be higher in Oriental, countries. A retrospective study was performed to analyze the clinical and pathological characteristics of sinonasal lymphomas/polymorphic reticulosis at Taichung Veterans General Hospital during a 14-year period. METHODS: At Taichung Veterans General Hospital, 37 patients with sinonasal lymphomas (including three patients with polymorphic reticulosis) were seen from November 1982 through September 1996. Excluding three patients without sufficient data, a total of 34 patients with their clinical records were reviewed. Clinical information regarding characteristics of the tumors, histological studies, treatment modalities and follow-up was collected for analysis. RESULTS: The 34 patients who underwent review showed a male-to-female ratio of 2.1:1. Median age was 60 years (range 13-83 years). The most common symptoms were nasal obstruction, nasal discharge/rhinorrhea and epistaxis. Median duration of symptoms at the time of diagnosis was two months. The most frequently involved sites were nasal cavities (right more than left side). There were 31 non-Hodgkin's lymphomas and three polymorphic reticuloses. The pathological classifications revealed 13 diffuse large cell lymphomas, 14 diffuse mixed small and large cell lymphomas and four pleomorphic T-cell lymphomas. Of the 21 adequately staged patients, 13 patients were in stage I; four, stage II; two, stage III and two, stage IV. The immunophenotypic study was performed in 20 patients. Eighteen (90%) of them were T-cell lymphomas and only two cases (10%) derived from B-cell. Though approach to therapy and follow-up periods varied during the time period covered by this study, the differences in survival according to treatment modalities were not statistically significant. The follow-up period ranged from 9 days to 130 months. The mean survival was 84.2 months. The overall five-year survival rate was 63%. CONCLUSIONS: The majority of the cases here were T-cell lymphomas. Most histologic grading by Working formulation belonged to the intermediate grade. Optimal treatment for such a group of patients still has no consensus, but adequate local control is important. If diagnosed and treated early, primary sinonasal lymphomas can be associated with a favorable outcome even with local treatment alone.
Adolescent↗
Tirapazamine (SR 4233) interrupts cell cycle progression and induces apoptosis.
Tirapazamine (Tira), a bioreductive agent, is highly toxic to cells under low oxygen conditions. Since active investigations of this agent are focusing on its potential as an adjunct of radiotherapy to improve overall effects on radioresistant hypoxic tumor cells, understanding its toxic mechanisms under aerobic conditions is important to the clinical application of this agent. Tira-treated V79 Chinese hamster cells were tested for cytotoxicity by colony assay and growth inhibition by the MTT assay. The survival of V79 cells after being exposed to 100 microM of Tira for 2 h was about 78% of untreated controls. The mitotic cell counts of V79 cells approached zero after 4 h treatment of Tira at 100 microM or 3 h at 300 microM. The fragmentation pattern of DNA isolated from cells 2 h after 300 microM Tira treatment showed characteristics of apoptotic cells. The induction of apoptosis by Tira was also detected by flow cytometric analysis and microscopic observation. These effects of Tira may be part of underlying toxic mechanisms to cells (including normal cells) under aerobic conditions.
Animals↗
Enhanced malignant progression of nasopharyngeal carcinoma cells mediated by the expression of Epstein-Barr nuclear antigen 1 in vivo.
Nasopharyngeal carcinoma (NPC) is consistently associated with Epstein-Barr virus (EBV) and mostly classified as poorly differentiated squamous cell carcinoma or undifferentiated carcinoma with early metastasis and a rapidly progressive clinical course. The EBV-encoded latent proteins, Epstein-Barr nuclear antigen 1 (EBNA 1) and latent membrane proteins (LMPs), may be expressed in NPC, but their biological effects are poorly understood. EBNA 1 may predispose B lymphocytes to lymphomagenesis in transgenic mice, but its biological effects in NPC are still unknown. This study investigated the biological effects of EBNA 1 by expressing it in an EBV-negative NPC cell line (HONE-1), which was then inoculated into both nude and severe combined immunodeficiency mice. The EBNA 1 caused HONE-1 cells to grow in a less differentiated pattern and to progress more rapidly, as well as increasing their tumourigenicity and metastatic capability. These data suggest that EBNA 1 may play a critical role in the progressive evolution of NPC.
Animals↗
Tumor necrosis factor-alpha suppresses the regrowth of fractionated irradiated endothelial cells in vitro.
Cytokines from two sources may affect endothelial cells (ECs) in tumor therapy: endogenously from cells in tumors and exogenously from therapeutic applications. These cytokines could modulate the influence of other therapy on tumor ECs. We use the colorimetric MTT method to assess the growth of irradiated ECs isolated from bovine pulmonary artery (CPAEC) and human umbilical cord vein (HUVEC) treated by cytokines. CPAECs given a single radiation dose of 2.5 to 15 Gy showed a small reduction in viable cells 2 to 3 days post-treatment. Neither tumor necrosis factor-alpha (TNF), interleukin-1 alpha (IL-1), nor interferon-gamma (INF) altered the growth of CPAECs treated by single radiation doses. HUVECs irradiated by a single dose of 12 Gy showed continuous reduction in viable cell numbers while those treated by 3 fractions of 4 Gy in 3 days or 6 fractions of 2 Gy in 3 days began to regrow 7 to 8 days after irradiation. Addition of TNF during the fractionated irradiation period limits the regrowth of HUVECs. Addition of IL-1 does not have the same effect. We have also tested the combined effect of another EC active agent flavone acetic acid (FAA), which has also been shown to stimulate the expression of TNF, with radiation, FAA (200 micrograms/ml) has a greater inhibitory effect on the growth and regrowth of fractionatedly irradiated HUVECs than TNF. These data suggest that TNF or FAA should be explored along with radiotherapy for their anti-tumor effect.
Animals↗
Clinical, physiologic, and pathologic evidence for vagus dysfunction in a case of traumatic brain injury.
A trauma victim with locked-in syndrome demonstrated severely decreased bowel sounds, intact response to suppository, and elevated, but unchanging pulse. Absent cardiac response to tracheal suctioning, high gastric residual volumes, and pulmonary edema in response to a urecholine challenge demonstrated dysfunction in the automatic system. Symptoms persisted for 2 1/2 years until death. At autopsy, asymmetric bilateral involvement of the dorsal motor nucleus of the vagus and of the nerve tract in the medulla were demonstrated. In contrast, a control subject with locked-in syndrome caused by a stroke did not demonstrate these phenomena. In trauma patients with delayed gastric emptying, measurement of the heart rate response to deep suctioning may lead to the diagnosis of this vagus dysfunction syndrome.
Adult↗
Correlative MR-anatomic study of the median nerve.
OBJECTIVE: The purpose of our study was to evaluate the effectiveness of MR imaging for showing the intrinsic anatomy of a peripheral nerve. Cadaver wrist specimens that included the median nerve were imaged with MR imaging at 3 T, then sectioned, stained, and inspected grossly and microscopically. The size, shape, and signal intensity of the sheath and axonal structures in the median nerve were identified in MR images by comparison with anatomic sections. CONCLUSION: This study suggests that MR imaging with sufficiently high-resolution techniques shows the internal structure of peripheral nerves. These results suggest that MR imaging may be a means to distinguish neuritis, tumor, degeneration, or fatty proliferation in a peripheral nerve and to evaluate the nerve before microsurgical anastomosis.
Adipose Tissue↗
MR appearance of the internal architecture of Ammon's horn.
PURPOSE: To determine whether the four subdivisions of Ammon's horn and six layers of CA1 seen histologically can be demonstrated with MR imaging. METHODS: Specimens of cadaver brains were imaged in a 3.0-T MR imager with a 3.0-cm solenoid coil. The specimens were sectioned, stained, and examined histologically. On anatomic sections, the four subdivisions of Ammon's horn and six layers of CA1 were identified. The MR images were then compared with the anatomic sections. RESULTS: Using geographic characteristics, we identified the four subdivisions of Ammon's horn. In CA1, the six layers could be identified by variations in signal intensity, width, and location. CONCLUSION: This study suggests that, with MR imaging of sufficiently high resolution, the internal architecture of Ammon's horn may be identified.
Brain Mapping↗
Ionic versus nonionic paramagnetic contrast media in differentiating between scar and herniated disk.
PURPOSE: To compare the MR contrast enhancement produced by ionic and nonionic paramagnetic contrast media in herniated disk fragments with that in epidural scar tissue. METHODS: A recurrent herniated disk was modeled in canines by using laminectomy to place a fragment of disk cartilage in the epidural space. The dogs were studied 88 and 90 days after laminectomy with MR imaging enhanced with an ionic or a nonionic paramagnetic contrast medium. Contrast enhancement of the epidural scar tissue and the epidural disk fragment was measured at 2, 22, and 45 minutes after the injection. RESULTS: Contrast enhancement was consistently and significantly higher in scar tissue than in disk fragments, although the difference decreased between 2 and 45 minutes after administration of contrast medium. Enhancement of disk fragments was less with the ionic than with the nonionic contrast medium. Contrast between the disk fragments and scar was also greater with the ionic than with the nonionic medium. CONCLUSIONS: The contrast between recurrent disk fragments and scar tissue is affected by the timing of the scan and the choice of contrast medium. Scans obtained immediately after the injection of contrast medium show more contrast between disk fragment and scar than do delayed scans. Recurrent herniated disk fragments are more effectively shown by ionic than by nonionic media.
Animals↗
Multiplanar MR and anatomic study of the mandibular canal.
PURPOSE: To evaluate the MR appearance of the mandibular canal and its contents. METHODS: Cadaveric mandibles were imaged at 1.5 T and 3 T, then sectioned with a cryomicrotome. The size, shape, signal intensity, and pattern of structures in the mandibular canal were identified on MR images by comparing them with corresponding anatomic sections. RESULTS: The inferior alveolar nerve and connective tissue were identified on the 1.5-T and 3-T images in the mandibular canal. Within the nerve the axon bundles were distinguished from the nerve sheath on the 3-T images. CONCLUSION: This study suggests that MR images can show excellent anatomic detail in the mandibular canal.
Cadaver↗
Quantitative evaluation of thallium-201 uptake in predicting chemotherapeutic response of osteosarcoma.
Thallium-201 has been shown to be useful in predicting tumour viability in patients undergoing neoadjuvant chemotherapy for osteogenic sarcoma. Early studies relied upon qualitative assessment of analog images to obtain predictive results. Recently, the lesion to normal tissue uptake ratio of 201Tl has been used in evaluating bone and soft tissue sarcomas. This study attempts to quantitate changes in tumour to normal tissue ratio following chemotherapy. Eight consecutive patients with classical osteosarcoma received standard preoperative chemotherapy with a combination of cisplatin, adriamycin and high-dose methotrexate. 201Tl gamma scintigraphic images were obtained both before and after chemotherapy. The average counts taken over the tumour divided by that from the contralateral normal tissue area yielded a tumour-to-normal tissue (T/N) ratio. The percentage change in the T/N ratio before and after preoperative chemotherapy was correlated with the percentage of tumour necrosis from pathological section. The median post-chemotherapy T/N ratio was 1.85 (range 0.5-7.7). The median percentage change in T/N ratio after chemotherapy was -58% (range +26% to -83%). The median percentage of necrosis from pathological section was 80% (range 0%-95%). There was a good correlation between the percentage of tumour necrosis and the percentage change in T/N ratio (rank correlation coefficient r = 0.84, P = 0.0085). Quantitative assessment of changes in 201Tl uptake by osteosarcoma correlates well with tumour necrosis after preoperative chemotherapy. This method may be used to predict response to chemotherapy at an earlier stage, enabling the clinician to consider alternative chemotherapeutic regimens or salvage surgery.
Adolescent↗
Assessment of p53 expression in nasopharyngeal carcinoma.
We analyzed the expression of the p53 protein by immunohistochemical methods from 101 patients with nasopharyngeal carcinoma (NPC): 24 with NPC and dysplastic lesions adjacent to carcinoma and 14 with primary and metastatic specimens. Ninety-six of 101 lesions (95%) had detectable p53 protein in the nuclei of tumor cells, indicating that overexpression of the p53 protein might be closely associated with NPC. Among 24 patients who had NPC and dysplastic lesions adjacent to carcinoma, 19 of the dysplastic lesions (79.2%) and 22 of the carcinomas (91.7%) showed positive staining for the p53 protein. In dysplastic epithelia p53 antigenicity was generally in a basal location. The significant association of p53 expression in NPC and dysplastic lesions adjacent to carcinoma (P < .0001, Fisher's exact probability test) suggests that p53 overexpression seems to occur at an early stage in the development of NPC. p53 expression in NPC does not correlate with histological grading, degree of lymphocytic infiltration between tumor cells, clinical stage, sex, or age (P > .05, chi-squared test). A comparison of p53 expression between primary and metastatic NPC was performed in 14 lesions. Although the p53 protein was consistently expressed in primary and metastatic tumor cells, there was no significant difference in p53 expression in both distinct but related lesions (P > .05, paired t-test). Our results suggest that the association of overexpression of the p53 protein in NPC may not be indicative of a mutant type p53 protein.
Adult↗
Nucleotide sequence of a sporamin gene in sweet potato.
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Base Sequence↗
Contrast enhancement in spinal nerve roots: an experimental study.
PURPOSE: To examine histopathologically the endothelium of contrast-enhancing spinal nerve roots. METHODS: In five adult baboons, chronic compression of the left S-1 spinal nerve root sufficient to produce a change in the evoked potential was produced by means of a suture tied around the nerve. The animals were studied with MR at 8 and 16 days after nerve compression and then killed for histopathologic and electron microscopic studies. Histopathologic changes in the nerve roots demonstrating contrast enhancement were described. RESULTS: In all compressed spinal nerves, contrast enhancement was observed. Histopathologically, wallerian degeneration of the root and inflammation and disruption of the endothelium of capillaries in the spinal nerve were evident. CONCLUSIONS: Degenerative changes in the nerve root and the capillary endothelium of a lumbar spinal nerve are associated with contrast enhancement.
Animals↗
Gadolinium-enhancement characteristics of magnetic resonance imaging in distinguishing herniated intervertebral disc versus scar in dogs.
STUDY DESIGN: This study is an experimental investigation on the gadolinium contrast magnetic resonance imaging (MRI) in distinguishing sequestered disc fragment versus scar in dogs. The conspicousness of the disc fragment and signal intensities of the disc fragment and laminectomy scar were evaluated using gadolinium-enhanced MRI and histology. OBJECTIVES: This study investigated the effects of timing of gadolinium injections, gadolinium doses, and aging of scar or disc on the enhancement characteristics and conspicuousness of disc fragment in MRI. SUMMARY OF BACKGROUND DATA: Contrast-enhanced MRI has been frequently used as a procedure to evaluate patients with suspected recurrent herniated discs. In contrast-enhanced MRI, the postoperative scar tissue enhances to a greater extent than disc fragments. Previous reports suggest different contrast enhancement characteristics of scar depending on doses, timing of gadolinium, or maturity of scar. There are different compounds of gadolinium agents and different doses are becoming available. There is no previous report on the evaluation of gadolinium enhancement characteristics in dogs with concurrent herniated disc and scar. METHODS: Six conditioned Beagle dogs underwent hemilaminectomies and discectomies at the L3-L4 level. An autogenous disc fragment was obtained from the intervertebral disc of the tail. This disc fragment was placed anterolateral to the thecal sac, simulating a sequestered disc herniation. Three control animals underwent hemilaminectomies and discectomies alone. Each dog underwent MRI on a 1.5 Tesla scanner (3.0 mm slice in sagittal and axial projections with TR 500, TE 30 msec and high dose 0.3 mmol/kg of gadoteridol). Images were obtained at 15 days, 30 days, 60 days, and 90 days after surgery. At each imaging session, contrast enhancement was measured at 2 minutes, 25 minutes, and 45 minutes after gadolinium injection for kinematic analysis. Two animals at a time were killed on 30 days, 60 days, and 90 days postoperatively. Magnetic resonance imaging was done with conventional low dose 0.1 mmol/kg of gadopentetate at 15 days and before death. RESULTS: Results revealed that the difference of enhancement between disc and the scar and therefore conspicuousness of disc fragment was greater on 2-23-minute images as compared with 45- minute images, and the distinction decreased with aging of the scar. The high dose contrast-enhanced MRI increased signal intensities for both disc and scar. Conspicuousness of disc fragment seemed to be better with the high-dose gadolinium compound. CONCLUSIONS: In conclusion, contrast enhancement characteristics in MRI may depend on the timing of MRI after gadolinium injection, doses of gadolinium, and aging of scar or disc.
Animals↗