Comments on "induction thermocoagulation-a seed power study".
Explore the source record for details and available documents.
Electric Conductivity↗
Biomedical subjects
J C Lin
Publications and source records attributed to J C Lin.
Immunospecificity to non-histone chromosomal proteins of anti-chromatin antibodies.
Explore the source record for details and available documents.
Animals↗
Nucleic acid metabolism during cytokinin induced cellular differentiation.
Edstrom's microphoresis technique has been employed to determine the quantitative alterations in nucleic acid content and base composition of individual cells associated with the initiation of bud primordia in Funaria hygrometrica. The filamentous protonema of this moss initiates bud cells which through repeated divisions form the leafy gametophores. The cytokinin, 6-furfurylaminopurine (kinetin), was used to induce the differentiation of bud cells from protonematal cells. The total RNA content of kinetin-induced bud cells (22.0 mumug/cell) was nearly 15 times that of protonematal cells (1.6 mumug/cell). The same dramatic increase in total RNA was apparent in bud cells which developed spontaneously in older cultures. As would be predicted, the adenine (A) to guanine (G) ratio for DNA from bud and protonematal cells was identical (0.7). The A:G ratio for RNA from bud cells (1.0) was much lower than that from protonematal cells (1.7). Thus, kinetin-induced differentiation in this system involves a dramatic increase in total RNA, the base composition of which approaches that of DNA. The base composition (A:G ratio) of DNA remains constant.
Cell Differentiation↗
Optimal dose of garlic to inhibit dimethylhydrazine-induced colon cancer.
This study was designed to investigate the optimal dose of garlic during long-term feeding and its preventive and therapeutic effects on colon cancer in rats induced by 1,2-dimethylhydrazine (DMH). A total of 240 male Sprague-Dawley rats were grouped and fed with either a basal or a garlic diet of different concentration, and some groups were subcutaneously injected with DMH 20 mg/kg once a week for 20 weeks. The incidence of colon tumor was significantly decreased in the groups fed with 2.5%, 5%, and 10% garlic diets (p < 0.001). There was no distinct difference among these concentrations (p > 0.05). Therefore the minimal optimal dose of garlic to inhibit colon cancer was 2.5%. The equivalent dose of this concentration in humans is 4.76 g/m2 body surface/day. In a therapeutic study, the tumor-inducing interval in nude mice subcutaneously injected with colon cancer cells (CC-M2) was prolonged by a 2.5% garlic diet (p < 0.01). Thus smaller tumor volume and longer survival time were found in the garlic group than in the controls (p < 0.01). However, the growth rate of tumors was not markedly inhibited by garlic. All rats finally died within 18 weeks. This study suggested that a 2.5% garlic dose may be used mainly as an inhibitor to prevent colon cancers and improve survival time.
Animals↗
Ependymoma of filum terminale: metrizamide-enhanced CT evaluation.
Two cases of surgically proven myxopapillary ependymomas of filum terminale are reported. In both, myelography and metrizamide-enhanced computed tomographic (CT) scans were performed. An intramedullary tumor in the lower thoracic spine, soft-tissue masses in the neural foramina and enlarged bony spinal canal in the lower thoracic and upper lumbar spine were noted in one case and, in the other, an intradural extramedullary tumor at T12-L1 level. Both patients had normal cranial CT scans, and both presented with similar symptoms--low back pain and weakness and paresthesia of leg or legs for up to 3 years' duration. Myelography and metrizamide-enhanced CT scans were performed in order to evaluate disc disease in one patient and spinal stenosis in the other. Ependymoma was an incidental finding, which was then removed by surgical resection. Pathology confirmed the diagnosis.
Adult↗
Synovial cysts of the lumbar spine: CT evaluation.
Seven cases of surgically proven intraspinal synovial cysts are reported. Computed tomographic (CT) scans demonstrated a series of low-density masses adjacent to the facet joints; in three cases, a dense rim indicated a calcified wall on the cyst; in one, the wall was partially calcified; and in three the mass appeared to be filled with gas. In all of these cases, there was severe degenerative facet disease at the same level as the synovial cyst. In six patients, the cysts were unilateral, while one was bilateral; seven cysts were located at the level of L4-L5, and one at L3-L4. We conclude from this study that the intraspinal synovial cyst can be identified reliably by the CT scan.
Aged↗
Congenital nasal pyriform aperture stenosis and single central maxillary incisor: CT and MRI findings.
The authors report five cases of congenital nasal pyriform aperture stenosis (CNPAS). Four cases are presented as neonatal nasal obstruction and also have single central maxillary incisor (SCMI). Computed tomography examination indicates three of the SCMI are unerupted and one is erupted. The fifth case has an erupted SCMI and short stature. The associated SCMI in CNPAS is believed to be more than an isolated anomaly. Awareness of the associated features of CNPAS among the radiologist and otolaryngologist may help the diagnosis and treatment of the patient.
Abnormalities, Multiple↗
Modulation of MDR-1 gene by MIF and GSTpi with drug resistance generation in hormone independent prostate cancer.
The expression of MIF and GSTpi were upregulated in prostate cancer cells with mulitdrug resistant phenotype. The aim of this study is to determine the relationship between these genes and multidrug resistance (mdr-1) gene in acquired multidrug resistance of prostate cancer. The expression of MIF, GSTpi and gp-170 in multidrug resistant (MDR) subline or native cells were determined using flow cytometry and western blotting. The mRNA level of various genes was analyzed with RT-PCR method. The chemosensitivity of tumor cells and stable transfectants to paclitaxel was measured using MTT (tetrazolium bromide) assay. The protein levels of MIF, GSTpi and gp-170 increased in MDR sublines of prostate cancer when compared with their parental cells. The MIF and GSTpi stable transfectants expressed higher MIF and GSTpi protein levels than their parental cells in western blotting analysis, respectively. The expression of mdr-1 gene and the production of pg-170 were also increased in either MIF or GSTpi stable transfectants when compared with vector control by using RT-PCR and flow cytometric analysis. The MTT results demonstrated that the increased chemoresistance was correlated with the increased production of gp-170 protein in either MIF or GSTpi transfectants. The upregulation of MIF and GSTpi during the development of acquired drug resistance of hormone independent prostate cancer may simultaneously and partially modulate the activation of gp-170.
ATP Binding Cassette Transporter, Subfamily B, Mem↗
Induction of thermoresistance in tumour blood vessels.
Explore the source record for details and available documents.
Acclimatization↗
Microwave sensing of increased intracranial water content.
A new technique to monitor brain edema is described that uses microwave energy to detect increased intracranial water content. By recording the phase of a transmitted microwave signal, increases in intracranial water content on the order of 1% are detected in vivo. These findings suggest that the progression of brain edema on a long-term basis can be assessed by progression of brain edema on a long-term basis can be assessed by our technique. Furthermore, phase changes related to small intracranial pressure variations are observed, indicating that the detection of pathologic pressure variations such as Traube-Hering-Mayer waves and plateau waves is possible by a noninvasive microwave technique.
Animals↗
Assessment of trabecular structure using high resolution CT images and texture analysis.
PURPOSE: Our goal was to use high resolution (HR) CT images combined with texture analysis to investigate the trabecular structure of human vertebral specimens and to compare these techniques with bone mineral density (BMD) in the prediction of bone strength. METHOD: HR CT images with a slice thickness of 1 mm were obtained of 28 bone cubes. Four different groups of texture analysis techniques were used to assess these images. In addition, quantitative CT (QCT) was performed and elastic modulus (EM) was determined biomechanically. RESULTS: R2 between EM and BMD was 0.78 (p < 0.01). R2 values for EM versus most of the texture measures were also significant. Texture measures in addition to measures of BMD in a multivariate regression model significantly increased R2 up to 0.87. CONCLUSION: In an experimental setting, texture parameters calculated using HR CT images correlated significantly with EM. Combining texture measures with BMD improved the prediction of EM significantly.
Adult↗
Applying telecommunication technology to health-care delivery.
Explore the source record for details and available documents.
Attitude of Health Personnel↗
Current developments in telemedicine.
Explore the source record for details and available documents.
Biomedical Engineering↗
Interstitial microwave antennas for thermal therapy.
This paper presents a new microwave antenna design with improved heating at the tip for interstitial hyperthermia and thermocoagulation. Temperature distribution patterns surrounding a conventional insulated antenna and the new sleeved coaxial slot radiator are measured in a saline phantom under transient and steady-state conditions. The new design provides an improved steady-state temperature distribution over the active region of the radiator. In contrast to the cold zone at the tip of a conventional insulated antenna the new sleeved coaxial slot antenna provides maximal (sixfold greater) power deposition at its tip.
Equipment Design↗
Combined treatment of IL-1 alpha and TNF-alpha potentiates the antitumour effect of hyperthermia.
Vasoactive cytokines, such as IL-1 alpha and TNF-alpha, modulate the homeostatic state at the endothelial surface and cause various types of pathological damage in vascular systems. We investigated the potential therapeutic effects of IL-1 alpha and TNF-alpha in combination with hyperthermia on SCK tumours grown in the legs of A/J mice. We first determined the effect of cytokines on tumour blood perfusion with the (86)Rb uptake method. When the host mice were given an i.p. injection of 25 mu g/kg IL-1 alpha or 50 mu g/kg TNF-alpha, the tumour blood perfusion markedly declined to 46 and 82% of control, respectively. The combination of IL-1 alpha and TNF-alpha reduced the 86Rb uptake to 41% bf control. Hyperthermia at 42.5 degrees C for 1 h reduced the tumour blood flow to 71% of control. The tumour blood perfusion decreased further to 20% of control when the tumours were heated for 1 h at 42.5 degrees C starting 4h after the injection of both IL-1 alpha and TNF-alpha. The changes in clonogenic cell numbers in SCK tumours, as determined by the in vivo-in vitro assay, following various treatments was also investigated. At 4 h after an i.p. injection of 25 mu g/kg IL-1 alpha or 50 mu g/kg TNF-alpha, the clonogenicity of SCK tumours significantly decreased to 29 or 37% of control, respectively. Heating at 42.5 degrees C for 1 h caused a decline in the clonogenic cell number to 30% of control. When both IL-1 alpha and TNF-alpha were given and tumours were heated 4h later at 42.5 degrees C for 1 h, the clonogenic cell number markedly declined to 0.4% of control. The time needed for control tumours to reach 4 x their initial volume was about 3 days, and treatment with IL-1 alpha or hyperthermia alone induced a tumour delay growth by about 1 day. The combined injection of IL-1 alpha and TNF-alpha followed by a heating at 42.5 degrees C for 1 h delayed the tumour growth by 6 days. The results in this study suggest that prior impairment of blood circulation by the combined treatment of IL-1 alpha and TNF-alpha potentiates hyperthermic damage in tumours.
Animals↗
The development of human exposure standards for radio-frequency fields.
Biological effects and health implications of radio frequency (RF) electromagnetic fields have been a subject of scientific investigation for more than 50 years. It has become a focus of attention because of the expanded use of RF radiation in the frequency range between 300 MHz and 6 GHz for wireless communication over the past decade. Another cause for the attention is the uncertainty of some observed responses and lack of understanding of the mechanism of interaction of RF electromagnetic fields with biological systems. At present, considerable efforts are devoted to developing and revising RF exposure standards. Each of these efforts should aim to make explicit the philosophy and process by which they reason and decide guidelines for deeming exposure as safe. Furthermore, the reconciliation of philosophies of protection will definitely be an asset, in practice, to those interested in international harmonization of RF exposure standards.
Environmental Exposure↗
Health aspects of radio and microwave radiation.
Recent publications are selectively reviewed to indicate the characteristics of radio and microwave interaction with biological systems. The emphasis is on low-level effects that occur at or below the currently accepted safety standard. This information is then used to examine the adequacy of existing emission and exposure standards for controlling the environmental levels of radio and microwave radiation, and safeguarding the general population from the deleterious effects resulting from typically encountered exposure in the United States.
Animals↗
QT prolongation and development of torsades de pointes with the concomitant administration of oral erythromycin base and quinidine.
Torsades de pointes is a polymorphic ventricular tachycardia characterized by marked QT prolongation on the electrocardiogram. It can be induced by both antiarrhythmic and nonantiarrhythmic drugs, such as quinidine and erythromycin. No extensive literature documents an interaction between quinidine and erythromycin when the agents are administered orally. A 95-year-old man received oral quinidine and erythromycin for the treatment of atrial fibrillation and community-acquired pneumonia. He developed torsades de pointes and subsequently cardiac arrest. Since erythromycin and quinidine are known to cause arrhythmias individually, caution and close monitoring are necessary when the drugs are administered concomitantly.
Aged↗