Influence of heavy metals in Parkinson's disease: an overview.

Parkinson's disease (PD) is an ageing disorder with deterioration of dopamine neurons which leads to motor complications like tremor, stiffness, slow movement and postural disturbances. In PD, both genetics as well as environmental factors both play a major role in causing the pathogenesis. Though there are surfeit of risk factors involved in PD occurrence, till now there is lack of an exact causative agent as a risk for PD with confirmative findings. The role of heavy metals reported to be a significant factor in PD pathogenesis. Heavy metal functions in cell maintenance but growing pieces of evidences reported to cause dyshomeostasis with increased PD rate. Metals disturb the molecular processes and results in oxidative stress, DNA damage, mitochondrial dysfunction, and apoptosis. The present review elucidates the role of cobalt, nickel, mercury, chromium, thallium metals in α-synuclein aggregation and its involvement in blood brain barrier flux. Also, the review explains the plausible role of aforementioned metals with a mechanistic approach and therapeutic recommendations in PD.

Photon activation therapy of RG2 glioma carrying Fischer rats using stable thallium and monochromatic synchrotron radiation.

75 RG2 glioma-carrying Fischer rats were treated by photon activation therapy (PAT) with monochromatic synchrotron radiation and stable thallium. Three groups were treated with thallium in combination with radiation at different energy; immediately below and above the thallium K-edge, and at 50 keV. Three control groups were given irradiation only, thallium only, or no treatment at all. For animals receiving thallium in combination with radiation to 15 Gy at 50 keV, the median survival time was 30 days, which was 67% longer than for the untreated controls (p = 0.0020) and 36% longer than for the group treated with radiation alone (not significant). Treatment with thallium and radiation at the higher energy levels were not effective at the given absorbed dose and thallium concentration. In the groups treated at 50 keV and above the K-edge, several animals exhibited extensive and sometimes contra-lateral edema, neuronal death and frank tissue necrosis. No such marked changes were seen in the other groups. The results were discussed with reference to Monte Carlo calculated electron energy spectra and dose enhancement factors.

An investigation of the early detection of radiation induced apoptosis by 99mTc-Annexin V and 201thallium-chloride in a lung cancer cell line.

This study aims to investigate the efficacy of in vitro Thallium-201 Chloride (Tl-201) and in vitro and in vivo Tc-99m HYNIC-coupled Annexin V (TAV) in the early detection of radiation induced apoptosis, a proxy indicator of radiation therapy (RT) efficacy. In vitro Tl-201 and TAV accumulation and efflux in non-small cell lung cancer were measured post irradiation at 5 different gamma ray doses. The replication rates (RR) of the cell lines were also measured. The same non-small cell lung cancer line was inoculated into the left femur. In vivo non-invasive Tl-201 and TAV tracer biodistribution studies were performed. Cell RR decrease with increased radiation dose was observed 48 hours after irradiation. Apoptotic cell number was found to have increased in response to 9 Gy and 12 Gy radiation dose. Tl-201 accumulation in the 9 Gy and 12 Gy irradiation groups was found to be higher than the lower irradiation groups. Quick Tl-201 efflux was observed in the 9 Gy and 12 Gy irradiated cells. At 48 hours after irradiation with 9 Gy and 12 Gy, Annexin V accumulation was found to be higher than in the control and 3-6 Gy groups. In vivo mouse model confirmed the increased TAV uptake in implanted tumors for relatively high 9 Gy irradiation as compared to non-irradiated controls. TAV may prove to be an effective radiotracer for early assessment of radiation therapy efficacy, via apoptosis, in human lung cancers.

Production of Ac-225 from Th-229 for targeted alpha therapy.

This work describes a method for the separation and purification of Ac-225 from a Th-229 source. The procedure is based on the combination of ion exchange and extraction chromatographic methods in nitric acid media and allows the preparation of carrier-free, clinical grade Ac-225 with an overall yield exceeding 95%. Quality control of the product is performed using radiometric (alpha, gamma spectrometry) and mass spectrometric methods. The Ac-225 product can be loaded on a radionuclide generator for the preparation of Bi-213 for preclinical and clinical studies of targeted alpha therapy of cancer and infectious diseases.

Theoretical analysis and experimental evaluation of a Csl(TI) based electronic portal imaging system.

This article discusses the design and analysis of a portal imaging system based on a thick transparent scintillator. A theoretical analysis using Monte Carlo simulation was performed to calculate the x-ray quantum detection efficiency (QDE), signal to noise ratio (SNR) and the zero frequency detective quantum efficiency [DQE(0)] of the system. A prototype electronic portal imaging device (EPID) was built, using a 12.7 mm thick, 20.32 cm diameter, Csl(Tl) scintillator, coupled to a liquid nitrogen cooled CCD TV camera. The system geometry of the prototype EPID was optimized to achieve high spatial resolution. The experimental evaluation of the prototype EPID involved the determination of contrast resolution, depth of focus, light scatter and mirror glare. Images of humanoid and contrast detail phantoms were acquired using the prototype EPID and were compared with those obtained using conventional and high contrast portal film and a commercial EPID. A theoretical analysis was also carried out for a proposed full field of view system using a large area, thinned CCD camera and a 12.7 mm thick CsI(TI) crystal. Results indicate that this proposed design could achieve DQE(0) levels up to 11%, due to its order of magnitude higher QDE compared to phosphor screen-metal plate based EPID designs, as well as significantly higher light collection compared to conventional TV camera based systems.

[Primary lymphoma of the thyroid with contralateral recurrence--case report]. / Primäres Lymphom der Schilddrüse mit kontralateralem Rezidiv--Ein Fallbericht.

Primary lymphomas located in the thyroid gland are rare clinical findings. The therapy and the subsequent monitoring of the disease continue to be a subject of debate. We present the case of a 63-year-old female patient in whom a hemi-thyroidectomy was performed because of a growing goiter. Histological examination of the excised tissue revealed a large-cell B-lymphocytic lymphoma which extended to neighboring lymph nodes. The patient received chemotherapy which led to remission of disease for two years. The disease re-occurred in the remaining thyroid lobe. Subsequently, the patient was treated with involved-field radiation therapy which lead to long term remission. We conclude that total thyroidectomy should be considered in the treatment of lymphomas located in the thyroid gland.

Estudio comparativo de perfusión miocárdica planar con talio 201 y mibi-Tc99m: correlación angiográfica / Comparative study of planar myocardial perfusion with thallium 201 and mibi-Tc99m: angiographic correlations

El presente trabajo tuvo como propósito comparar el estudio de perfusión miocárdica planar efectuado con talio-201 con el de mibi-tecnecio-99m (Tc99m) y correlacionarlos con coronariografía contrastada en pacientes coronarios. Se estudiaron 120 pacientes, en estrés y en reposo, 60 con talio-201 y los otros 60 con mibi-Tc99m. Se obtuvieron imágenes con gammacámara y computador en 3 proyecciones en ambas condiciones, y se efectuó análisis cuantitativo de la información por pacientes, por segmentos miocárdicos y por vaso coronario. Por pacientes, la sensibilidad del test de talio-201 fue de 88 por ciento y la del mibi-Tc99m de 90 por ciento (p= no significativo), considerando el esfuerzo y el dipiridamol en forma global, y la especificidad fue de 40 por ciento para el talio-201 y de 91 por ciento para el mibi-Tc99m (p<0,001). Por segmentos, la sensibilidad del talio-201 fue de 54 por ciento y la del mibi-Tc99m fue de 53 por ciento (p= no significativo) y la especificidad del talio-201 fue de 78 por ciento y la del mibi-Tc99m fue de 87 por ciento (p<0,0002). Por vaso coronario, sólo resultó significativamente más específico el mibi-Tc99m (86 por ciento) que el talio-201 (76 por ciento) para la arteria descendente anterior (p<0,02). Se concluye que el mibi-Tc99m es significativamente más específico que el talio-201

Role of radionuclides in acute cardiac care: current status.

The aforementioned studies demonstrate the varied and important clinical information concerning acute myocardial infarctions that is obtainable from certain radionuclide procedures. Limitations of these procedures as well as futuristic improvements are also discussed.

Studies on the antitumor activity of gallium nitrate (NSC-15200) and other group IIIa metal salts.

Several group IIIa metal salts, eg, aluminum nitrate, gallium nitrate, indium nitrate, and thallium chloride, have been evaluated for in vivo toxicity in mice and rats, for cytotoxicity in tumor cells in vitro, and for activity against a broad spectrum of experimental rodent tumors. The position of these agents in the periodical table roughly parallels their toxicity, the LD50s decreasing with increasing atomic weights. This parallel also exists with regard to in vitro cytotoxicity to Walker 256 carcinosarcoma cells. Although all of the metal salts had activity against the ascites Walker 256 carcinosarcoma, they were ineffective in ascites leukemias, plasma cell tumors, or Ehrlich carcinoma. Gallium nitrate was particularly active against solid tumors transplanted subcutaneously, suppressing the growth of six of eight tumors more than 90%. Because of its demonstrated antitumor activity in rodents and its uptake and concentration by various animal and human tumors, gallium nitrate has potential usefulness in the treatment of solid tumors in man and has been entered into a phase I study at the National Cancer Institute.