Radiosynthesis of [191]Os-2-acetylpyridine thiosemicarbazone complex, as an in vivo therapeutic radionuclide generator

Due to the anti-proliferative properties of platinum group-thiosemicarbazone complexes, the production of [191]Os-labeled 2-acetyl pyridine 4-N-methylthiosemicarbazone [[191]Os-APMTS] was investigated. [[191]Osmium [T[1/2]= 15.4d] was produced via the [190]Os[n,gamma][191]Os nuclear reaction using enriched target irradiated with thermal neutrons. Reaction of in-house synthesized 2-acetylpyridine thiosemicarbazone [APMTS] with [191]Os yielded [[191]Os]APMTS checked by ITLC followed by stability, partition co-efficient and biodistribution determination. Following synthesis and spectroscopic determination of the ligand [>99% chemical purity], the complex was prepared with a radiochemical purity of more than 95% [RTLC] and specific activity of 21.5 GB/mM and was stable in the formulation and presence of human serum at 37[degree sign]C for up to 48h. The partition coefficient was determined [log P. 1.23]. The biodistribution study up to 4 days demonstrated significant tissue uptake differences in the bone, blood, heart and thyroid. This is the first Os-191 labeled thiosemicarbazone designed as an in-vivo therapeutic radionuclide generator. Further investigation is ongoing on the evaluation of the complex in tumor bearing animals

Osmium [VIH]-catalyzed oxidation of indoles by potassium hexacyanoferrate [III] in alkaline media: a kinetic and mechanistic study

The reaction of indoles with Os [VIII] catalyzed hexacyanoferrate [III] in alkaline media to produce the corresponding oxindole has been studied at constant temperature and ionic strength. The reaction followed first order kinetics with respect to [indole], [OH[-] and [Os [VIII]], fractional order in [Fe[CN][6][-3]. The effects of added electrolytes, potassium hexacyanoferrate [II], relative permitivity and temperature have also been studied. A mechanism consistent with the kinetic data is proposed. Furthermore, the structural influence of the indoles on the reactivity has been discussed

The Effect of Prolonged Water Exposure on the Epidermal Permeability Barrier / 대한피부과학회지

BACKGROUND: Water exposure is considered an important causative factor of irritant contact dermatitis. It is also known that water exposure can disrupt the stratum corneum (SC). However, there are only a few morphologic studies on the effect of water contact on the skin. OBJECTIVE: The aim of our study was to investigate the effects of prolonged water exposure on the permeability barrier and the ultrastructure of the SC intercellular lipids. METHODS: After prolonged water exposure of hairless mouse skin in vivo for 24, 36, 48, and 72 hrs respectively, the permeability barrier function was assessed by transepidermal water loss (TEWL) measurement, and the ultrastructure of SC by electron microscopy using osmium tetraoxide and ruthenium tetraoxide postfixation and calcium ion capture cytochemistry. Additionally, the lipid composition was evaluated using confocal microscopy with nile red stain and the integrity of the SC assessed using a lanthanum tracer. RESULTS: After prolonged water exposure, water caused a significant increase in TEWL with disappearance of the calcium gradient, but this did not significantly influence the recovery rate of TEWL. The intercellular lipids were disrupted, and multiple lacunae containing abnormal delaminated materials within the intercellular spaces were observed. Lanthanum tracer penetrated into the intercellular space of the SC. There was a progressive decrease in nile red staining with neutral lipid content. With increasing exposure to water, these results were more evident. CONCLUSION: Our results provide a better understanding of the disruptive effect of prolonged water exposure on barrier lipids, the penetration-enhancing effect of water and the increased susceptibility to irritants, with regard to duration of water exposure.

An experimental study on the microvascular anastomosis in applying the frozen arterial allograft in the rats

Although the autogenous vein graft is the most reliable in the fields of microvascular reconstruction, the microvascular allograft and microvascular prosthesis have been developed to be substitute for autogenous vein because it has many problems. In many experimental study have been reported highly variable patency rate and its thrombogenetic property of microvascular allograft. Especially, antigenicity of the homogenous vessels and immune reaction-induced thrombosis are main cause of homogenous microvascular anastomosis failure. For that reason, several investigators have attempted to reduce the antigenicity and improve the patency rate of microvascular allograft. The purpose of this study was to observe the healing process in applying frozen arterial allograft in the rats. In order to perform this study, 27 Sprague-Dawley rats, weighing 300gm or more selected. 12 carotid arterial anastomoses were performed in the rats by using microvascular end-to-end anastomosis as control group and 15 frozen(-196degreesC) arterial allografts were implanted into the carotid artery in the rats by using microvascular anastomosis as experimental group. The experimental rats were sacrificed on the 1st, 3rd, 7th, 14th, 28th, 56th day after operations. For scanning electron microscopic study, fixation was performed by perfusion of 2.5% glutaraldehyed-2% paraformaldehyed in 0.1M phosphate buffer at pH7.3. The specimens were post-fixated in 1% osmium tetraoxide for 2 hours, washed with cacodylate buffer, dehydrated in a series of ascending ethanol baths, critical point dried, coated with gold in a vacuum evaporator, and observed with a scanning electron microscope(JEOL, JSM-840-A, 20kV). For histologic examination taken specimens were embedded in paraffin, sectioned 6-8micrometer in thickness. The specimens were stained with hematoxylin-eosin stain method, examined under light microscope. The results were as follows; 1. The patency rate of control group was 92% and experimental group was 86%. 2. Endothelial cells regeneration at the anastomosis site of both group was partially appeared on the 1st week after experiment. 3. On the 2nd week after experiment, anastomosis site was completely covered with regenerated endothelial cell in both group, and the endothelial cell proliferated toward the graft at experimental group. 4. On the 4th, 8th week after experiment, the grafted artery was partially covered with endothelial cell at experimental group.

The Effects of Ascorbic Acid on the Growth of the Fetal Rat Bone in Ca++ / 대한정형외과학회잡지

In order to study the effect of ascorbic acid on the growth of the fetal rat long bones in calcium free culture medium, fetal femurs from rat fetus on 19th day of gestation were cultured for 1, 3, 5, 7 and 9 days in medium described below. Culture media used were MEM, Ca++