Exploring Electrochemistry: A Hydrogen Peroxide Sensor Based on a Screen-Printed Carbon Electrode Modified with Prussian Blue

There is an increasing need for fundamental electrochemistry concepts to be taught in the undergraduate curriculum, given the broad applicability of electrochemical technologies in addressing a wide range of global issues from critical energy shortages to real-time medical diagnostics. However, many electrochemical concepts are often taught in disparate laboratory experiments, spread out through the curriculum, which can be intimidating to students (and instructors). This experiment, which has been tested and optimized in the undergraduate classroom over multiple semesters, covers a wide range of electrochemistry topics in realizing the construction of a hydrogen peroxide (H2O2) sensor that is based on Prussian blue electrochemistry. The experiment introduces the fundamentals of cyclic voltammetry by prompting students to distinguish faradaic and capacitive components of voltammograms and to investigate their relationship with scan rate as per electrochemical theory. Students also evaluate electrocatalysis through electrodeposition of a thin film of Prussian blue on the sensor surface and the effects of this modification on electron transfer and sensor performance. Finally, students combine amperometric measurements with the method of standard additions to determine H2O2 concentrations in an unknown sample. Overall, this experiment offers an integrated and cohesive experience that connects many important electroanalytical concepts that are often taught individually into one 3 h, hands-on laboratory experiment that requires minimal resources.

[Plasmocytoma of the ureter--a rare cause of hydronephrosis: case report and review of the literature]

INTRODUCTION

Plasmocytoma is an aggressive B-cell lymphoma with diffuse and multi-located-infiltration of the bone marrow. There are only a few cases in the literature reporting an extraosseous manifestation of plasmocytoma, e. g., in the urinary tract.

CASE REPORT

We report on an 80-year-old female patient with known plasmocytoma presenting with renal colics. Ultrasonography demonstrated marked hydronephrosis and retrograde pyelography disclosed a short and filiform stenosis of the ureter. Surgical exploration revealed an infiltration of the distal ureter by the known plasmocytoma. The affected ureter segment could be removed completely and ureterocystoneostomy was performed successfully.

CONCLUSIONS

To the best of our knowledge, we present the first case of an isolated plasmocytoma of the ureter. Although extremely rare, it should be considered as a differential diagnosis of circumscribed ureteral strictures.

Radiochemotherapy after transurethral resection is an effective treatment method in T1G3 bladder cancer

AIM

Conservative therapy using deep transurethral resection (TUR) followed by radiochemotherapy is a novel treatment strategy in stage TI grade 3 (TIG3) transitional cell carcinoma (TCC) of the bladder. The aim of this study was to present our long-term results of radiochemotherapy in T1G3 TCC patients.

MATERIALS AND METHODS

A total of 64 patients with TIG3 TCC of the bladder underwent a TUR and a subsequent radiochemotherapy protocol at our institution. Following TUR, a median dose of 55.8 (range; 45-69.4) Gy radiation therapy was applied to the bladder, and simultaneous chemotherapy was initiated using cisplatin, carboplatin and/or 5-fluorouracil. After completion of the protocol, response was evaluated by repeat TUR, and check cystoscopies were performed at regular intervals. Median patient age was 66 (range; 30-82) years and median follow-up was 43.2 (range; 6-127) months.

RESULTS

Complete response was achieved in 55 (90.2%) patients. Of the complete responders, 7 patients experienced a superficial (Ta, T1) recurrence and 8 patients had progression. In 8 patients with refractory superficial and invasive relapses, a salvage cystectomy was mandated. The overall progression rate was 14%. The overall and disease-free survival rates were 76% and 93%, respectively at 5 years. During followup, 4 patients suffered from reduced bladder capacity, and 2 patients underwent cystectomy due to shrinking bladder.

CONCLUSION

Combined multimodality therapy is a safe and curative treatment option for patients with T1G3 TCC of the bladder in the hands of dedicated multimodality teams. Therefore, it is reasonable to justify radiochemotherapy combined with TUR in the first-line treatment of T1G3 tumors.

Tolerance of half-body irradiation as systemic therapy for patients with locally advanced breast cancer

BACKGROUND

Locally advanced breast cancer (LABC) is one of the main causes of cancer death among women in Bulgaria. In 1988, when this study started, there was still controversy about the role of chemotherapy in controlling systemic disease. There were encouraging results from the Radiation Therapy Oncology Group (RTOG) 82-06 study suggesting that half-body irradiation (HBI) should be used earlier in the disease course to prevent the development of metastases. There were many patients with LABC requiring treatment, but there was a problem with obtaining the drugs needed; they were expensive and not consistently available.

PROCEDURE

Taking into account the medical contraindications to chemo-therapy treatment, its toxicity, and the possibility of chemoresistance, we initiated this study to look at the effects of HBI given as two fractions of 4 Gy to the upper and then lower parts of the body, after surgery and before local radiotherapy.

RESULTS

The acute tolerance of this regimen in 36 patients with LABC was as good as it was in 4 additional LABC patients with M1 disease, and hematologic recovery was satisfactory.

CONCLUSIONS

We conclude that systemic treatment with HBI is tolerable. It therefore may be a convenient and cost-effective treatment for LABC, although better treatments are still needed.