The association between renal elasticity evaluated by Real-time tissue elastography and renal fibrosis

Clinical and Experimental Nephrology - The progression of chronic kidney disease (CKD) depends on the extent of fibrosis in the kidneys; however, a renal biopsy is necessary to evaluate the...     

A digest of the Evidence-Based Clinical Practice Guideline for Nephrotic Syndrome 2020

Clinical and Experimental Nephrology -     

Protein tyrosine phosphatases

Protein tyrosine phosphatases (PTPases) balance the action of tyrosine kinases to maintain a set level of cellular tyrosine phosphorylation. Increases in tyrosine phosphorylation produced by transformation with constitutively active tyrosine kinases can initiate cellular proliferation. PTPases may act as tumor suppressors to counteract the transforming potential of oncogenic kinases. However, recent evidence suggests that PTPases have the potential to act as positive mediators of mitogenic signaling. If PTPases are acting as tumor suppressors, the expression of an inactive PTPase may cause an increase in overall tyrosine phosphorylation of cellular proteins, resulting in cellular transformation. Alternatively, overexpression of PTPases that play a positive role in signal transduction might also lead to proliferation. The role that each PTPase plays may depend in the cellular context in which it is expressed.     

Intracellular activation and cytotoxic action of RS-1541 against cultured human tumor cells

RS-1541, an acyl-derivative of rhizoxin (Fig. 1), is a potent antitumor compound. This agent showed cytotoxicity in vitro on some cultured human tumor cells, although it was less potent than rhizoxin. Rhizoxin exhibited antitumor effects by inhibiting the polymerization of tubulin, whereas RS-1541 did not inhibit tubulin polymerization in vitro. However, cell cycle analysis in vivo showed that the two agents had the same mode of action. The cytotoxicity of RS-1541 was enhanced when the initial cell density of the cells was increased. The cytotoxicity was also enhanced when the membrane fraction of St-4 cells, which were the most sensitive to RS-1541 among the cell lines tested, was added to the target cells. When St-4 cells were incubated with [¹⁴C]-RS-1541, significant amounts of [¹⁴C]-rhizoxin were produced within the cells. Further fractionation of the crude membrane showed that the activity that enhanced the cytotoxicity of RS-1541 (RS-1541-enhancing activity) belonged to the mitochondrial-lysosomal fraction, not to the microsomal fraction. Both the enhancing activity and the activity that converting [¹⁴C]-RS-1541 to [¹⁴C]-rhizoxin (RS-1541-converting activity) were inhibited by treatment with chloroquine, an inhibitor of lysosomal function. Cholesterol esterase derived fromCandida cylindracea had RS-1541-enhancingand-converting activities. These data suggest that RS-1541 exerts its cytotoxic action after being converted to rhizoxin within the cells by a lysosomal enzyme such as cholesterol esterase.Abbreviations DMSO Dimethylsulfoxide - PBS(-) Ca²⁺ Mg²⁺-free phosphate-buffered saline - HCO60 hydrogenated castor oil polyethylene glycor ether - DMA dimethylacetamide - RSB reticulocyte standard buffer, consisting of 10mM NaCl, 1.5 mM MgCl₂, and 10 mM TRIS-HCl, (pH 7.4) - TLC thin-layer chromatography - ara-C 1--D-arabinofuranosylcytosine - LDL low-density lipoprotein     

Investigation of radiation safety management of nuclear medicine facilities in Japan; contamination of radioactivity in the draining-water system. A Working Group of Japanese Society of Nuclear Medicine for the Guidelines of Nuclear Medicine Therapy

Radiation safety management condition in Japanese nuclear medicine facilities were investigated by the questionnaire method. The first questionnaire was asked in all Japanese 1,401 Nuclear Medicine facilities. Answers from 624 institutes (44.5%) were received and analyzed. The radiation-safety management in nuclear medicine institutes was considered to be very well performed everyday. Opinion for the present legal control of nuclear medicine institutes was that the regulation in Japan was too strict for the clinical use of radionuclides. The current regulation is based on the assumption that 1% of all radioactivity used in nuclear medicine institutes contaminates into the draining-water system. The second questionnaire detailing the contamination of radioactivity in the draining-water system was sent to 128 institutes, and 64 answers were received. Of them, 42 institutes were considered to be enough to evaluate the contamination of radioactivity in the draining-water system. There was no difference between 624 institutes answered to the first questionnaire and 42 institutes, where the radioactivity in the draining-water system was measured, in the distribution of the institute size, draining-water system equipment and the radioactivity measuring method, and these 42 institutes seemed to be representative of Japanese nuclear medicine institutes. Contamination rate of radioactivity into the draining system was calculated by the value of radioactivity in the collecting tank divided by the amount of radionuclides used daily in each institute. The institutes were divided into two categories on the basis of nuclear medicine practice pattern; type A: in-vivo use only and type B: both in-vivo and in-vitro use. The contamination rate in 27 type A institutes did not exceed 0.01%, whereas in 15 type B institutes the contamination rate distributed widely from undetectable to above 1%. These results indicated that the present regulation for the draining-water system, which assumed that 1% of all radioactivity used in nuclear medicine institutes contaminated into draining-water system, should be reconsidered in nuclear medicine facilities where radionuclides are used only in in-vivo studies.     

Dynamic 99Tcm-ECD SPET correlates well with 201Tl indices in brain tumours

The dynamic 99Tcm-ethyl cysteinate dimer (99Tcm-ECD) single photon emission tomographic (SPET) characteristics of brain tumours were investigated and compared with 201Tl-chloride SPET indices. Thirty-five patients with histologically confirmed benign and malignant tumours were evaluated using dynamic and standard 99Tcm-ECD. Twenty-eight patients were also examined using standard 201Tl SPET. The following 201Tl indices were calculated: early uptake ratio, delayed uptake ratio, washout rate and retention index. The relationship between uptake of 99Tcm-ECD on dynamic SPET and 201Tl indices was analysed. Nine patients showed positive uptake on dynamic 99Tcm-ECD SPET, all of whom had benign tumours, including five meningothelial meningiomas, three pituitary adenomas of the chromophobe type and one chemodectoma without malignancy. The mean early uptake ratio of the tumours with positive uptake was significantly higher than that of the tumours with negative uptake (17.1 +/- 5.5 vs 9.0 +/- 5.7, P = 0.004). The mean washout rate of the tumours with positive uptake was significantly higher than that of the tumours with negative uptake (61.0 +/- 27.7 vs 0.35 +/- 30.9, P = 0.0004). The mean retention index of the tumours with positive uptake was significantly lower than that of the tumours with negative uptake (0.27 +/- 0.12 vs 0.88 +/- 0.48, P = 0.000006). Only benign tumours showed positive uptake on dynamic 99Tcm-ECD SPET. The 201Tl indices correlated well with the uptake of 99Tcm-ECD on dynamic SPET. The results suggest that dynamic 99Tcm-ECD SPET can identify the benign character of tumours of the brain.     

Expandable metallic stent treatment for malignant colorectal strictures

Four patients were treated by placement of an expandable metallic stent (two Gianturco Z-stents, two Ultraflex stents) for malignant colorectal strictures. All four patients were able to defecate after stent placement. Stent migration was recognized in one patient. Two patients suffered from tenesmus after stent placement.     

Evaluation of the accuracy of preoperative staging in thoracic esophageal cancer

Background. Exact clinical staging before treatment of esophageal cancer has become increasingly important in the evaluation and comparison of the results of different treatment modalities, including surgery, chemotherapy, and radiotherapy.

Methods. The accuracy of preoperative tumor staging by using an esophagography, esophagoscopy, percutaneous and endoscopic ultrasonography, and computed tomography was assessed in 224 patients with resectable esophageal cancer. The results of tumor staging by these tests were compared prospectively with the pathologic stage of the esophagectomy specimens with respect to the T and N categories defined by the International Union Against Cancer TNM classification.

Results. For the T category, the overall accuracy was 80%. For the N category, overall accuracy was 72%, with a sensitivity of 78%, a specificity of 60%, and a positive predictive value of 78%. Overall, the accuracy of stage grouping was 56%.

Conclusions. Either the T or N categories can be predicted reliably by clinical staging techniques. However, the preoperative stage grouping might not be valid in resectable, localized esophageal cancer.