Preparation and Biological Evaluation of 67Gallium- Labeled Iranian Hemiscorpius Lepturus Scorpion Venom.

BACKGROUND: The Hemiscorpius lepturus (H. lepturus) is a deadly scorpion species living in the southern Iran. OBJECTIVE: H. lepturus induces delayed toxicity symptoms and understanding the long term biodistribution/ biokinetic of the venom is of great interest in toxicology. METHODS: A Ga-67 labeled venom was prepared using a DOTA -conjugated venom followed by radiolabeling using 67GaCl3 at 40°C for 90 min. The purification of the radiolabeled venom was performed using size exclusion-chromatography (radiochemical purity 71%). The radiolabeled venom was stable in the final solution in the presence of human serum at 37°C for 72 hours. The tissue distribution was studied in blood, heart, liver, spleen, muscle, brain, kidney, intestine and skin tissues at the intervals of 1, 4, 24, 48 and 72 hours using tissue counting and SPECT imaging. RESULTS: The radiolabeled venom mixture obtained with an estimated molar activity of 0.52 MBq/µg. The main accumulation tissues during the first 72 hours were kidneys, blood, liver, intestines, stomach and skin, respectively. Therefore, it is likely that H. lepturus' clinical effects and renal toxicity are primary and caused by direct effects of the H. lepturus venom. CONCLUSION: The results have largely shown the direct clinical effects on the studied tissues during the 72-hour period and antivenom administration can strongly alleviate the toxicity effects as early as 72 hours in the management of the patients.

Biological Evaluation of 99mTc-HYNIC-EDDA/tricine-(Ser)-D4 Peptide for Tumor Targeting.

BACKGROUND: D4 small peptide (Leu-Ala-Arg-Leu-Leu-Thr) was selected as an appropriate agent for specific targeting of epidermal growth factor receptor (EGFR). OBJECTIVE: The aim of study was to investigate the 99mTc-labeled D4 peptide for non-small cell lung tumor targeting. METHOD: HYNIC-(Ser)3-D4 peptide was labeled with 99mTc using mixture of tricine and ethylenediamine diacetic acid (EDDA) as co-ligands. The in vitro cellular uptake of radiolabeled peptide was evaluated by blocking test on human non-small cell lung cancer (A-549) cell line and its biodistribution was evaluated in A-549 xenografted nude mice. RESULTS: This conjugated peptide was labeled with 99mTc in high radiochemical purity and it was highly stable in buffer and serum. The un-blocked to blocked cellular radioactivity ratio was 4- fold that showed a specific binding of this radiolabeled peptide on A-549 cell. Animal biodistribution in A-549 xenografted nude mice showed rapid clearance from blood and other non-target organs. Tumor uptake values as %ID/g (percentage of injection dose per gram of tissue) were 2.47% and 1.30% at 1 and 4 h after injection. CONCLUSION: This study showed the 99mTc-EDDA/tricine-HYNIC-(Ser)3-D4 peptide had tumor targeting on the non-small cell lung tumor.

99mTc-HYNIC-D4 Peptide: A New Small Radiolabeled Peptide for Non Small Cell Lung Tumor Targeting.

OBJECTIVE: The aim of this study was to evaluate the 99mTc-HYNIC-D4 peptide as a new radiotracer for tumor targeting in non small cell lung tumor that overexpresses epidermal growth factor receptor (EGFR). METHOD: D4 small peptide (Leu-Ala-Arg-Leu-Leu-Thr) was selected as a candidate for specific targeting on EGFR. It was conjugated with HYNIC on N-terminus and labeled with 99mTc using tricine as a co-ligand. The cellular and animal studies were evaluated for specific binding of this labeled peptide. RESULT: Radiochemical purity was determined to be 98% by instant thin layer chromatography and reverse-phase high performance liquid chromatography. Stability of radiolabeled peptide was more than 90% up to 24 h incubation in solution at 37 oC. Specific binding of the radiolabeled peptide to the EGFR showed dissociation constant of 181 ± 41 nM. Animal biodistribution in normal and A-549 xenografted nude mice showed rapid clearance from blood and other non target organs. Tumor uptake values as %ID/g (percentage of injection dose per gram of tissue) were 8.07% at 1 h and 3.82% at 4 h after injection that was blocked by presaturation of EGFR using an excess of cold peptide. CONCLUSION: This study showed that 99mTc-HYNIC-D4 is a promising tumor targeting radiotracer on the non small cell lung tumor.

Role of CHK2 inhibitors in the cellular responses to ionizing radiation.

Ionizing radiation is the more effective therapy to reduce tumor growth through damaging the DNA of cells. In response to DNA damage, cells activate the checkpoint kinases such as CHK2, which signal to initiate repair processes and cell-cycle arrest, until the damaged DNA is repaired. At present, the development of CHK2 inhibitors has provided an interesting strategy for the treatment of cancer by introducing new radiation modifier agents. CHK2 inhibitors can contribute for the improvement of cancer therapy through sensitizing cancerous cells and radioprotection of normal cells against ionizing radiation. This review describes and discusses the most recent inhibitors of CHK2 and presents an evaluation of chemical structures and biological activities. As well as their role in cell growth during exposure to ionizing radiation.

Design and synthesis of 2-phenoxynicotinic acid hydrazides as anti-inflammatory and analgesic agents.

A series of 2-phenoxynicotinic acid hydrazides were synthesized and evaluated for their analgesic and anti-inflammatory activities. Several compounds having an unsubstituted phenyl/4-pyridyl or C-4 methoxy substituent on the terminal phenyl ring showed moderate to high analgesic or anti-inflammatory activity in comparison to mefenamic acid as the reference drug. The compounds with highest anti-inflammatory activity were subjected to in vitro COX-1/COX-2 inhibition assays and showed moderate to good COX-1 and weak COX-2 inhibition activities.