As many new drug substances contained various aromatic rings and fluorine attached to an electron rich aromatic ring or on the meta-position, a strategy towards improvement in aromatic fluorination of these compounds is highly desirable. The introduction of fluorine-18 onto aromatic rings showed in the limited condition containing electron withdrawing group (EWG) on the para- or ortho-position to get reasonable radiochemical yield so far. No-carrier added (NCA) [18F]fluoroarene syntheses by iodonium salts recently reported that has the potential to greatly increase the yield in systems or positions that normally not reactive enough to give sufficient yields in simple model reaction. This review describes the methodological approach towards effective aromatic fluorination by diaryliodonium salts and future prospects in an application of novel PET radiotracer.
Electrons ; Fluorine ; Halogenation ; Salts

PURPOSE: The purpose of this study was to evaluate the efficiency of a gas-phase fluorination method under different fluorination periods through using two resin cements. MATERIALS AND METHODS: 84 zirconia specimens in dimensions of 5 mm × 5 mm × 2 mm were prepared and surface treated with 50 µm aluminum oxide particles or gas phase fluorination for 2 min, 5 min, or 10 min. One specimen in each group was surface analyzed under scanning electron microscope. The remaining specimens were bonded to composite cylinders in dimensions of 2 mm diameter and 3 mm high with Panavia SA Plus or Variolink N. Then, the specimens were stored in 37℃ distilled water for 24 hours and shear bond strength test was applied at a speed of 1 mm/min. RESULTS: The highest shear bond strength values were observed in the samples fluorinated for 5 minutes and cemented with Panavia SA Plus. Variolink N did not elicit any statistical differences between surface treatments. Panavia SA Plus resin cement and Variolink N resin cements featured statistically significant difference in shear bond strength values only in the case of 5 minutes of fluorination treatment. CONCLUSION: According to the results of this study, application of 5 minutes of fluorination with 10-methacryloyloxydecyl dihydrogen phosphate monomer (MDP) containing Panavia SA Plus resin cement increased the resin bond strength of zirconia. Fluorination of the zirconia surface using conventional resin cement, Variolink N, did not lead to an increase in bond strength.
Aluminum Oxide ; Ceramics ; Halogenation ; In Vitro Techniques ; Methods ; Resin Cements ; Water

2-Haloacid dehalogenases (EC 3.8.1.X) catalyze the hydrolytic dehalogenation of 2-haloacids, releasing halogen ions and producing corresponding 2-hydroxyacids. The enzymes not only degrade xenobiotic halogenated pollutants, but also show wide substrate profile and astonishing efficiency for enantiomer resolution, making them valuable in environmental protection and the green synthesis of optically pure chiral compounds. A variety of 2-haloacid dehalogenases have been biochemically characterized so far. Further studies have been made in protein crystal structures and catalytic mechanisms. Here, we review the recent progresses of 2-haloacid dehalogenases in their source, protein structures, reaction mechanisms, catalytic properties and application. We also suggest further research directions for 2-haloacid dehalogenase.
Catalysis ; Halogenation ; Hydrolases ; chemistry ; metabolism ; Hydrolysis ; Research ; trends ; Substrate Specificity

PURPOSE: We designed our study to evaluate the hypothesis that gastric cancer is correlated with iodine deficiency or thyroid dysfunction. MATERIALS AND METHODS: We investigated the total body iodine reserve, thyroid function status and autoimmune disorder in 40 recently diagnosed gastric adenocarcinoma cases versus 80 healthy controls. The participants came from a region with high gastric cancer rate but sufficient iodine supply due to salt iodination. The investigation included urine iodine level, thyroid gland clinical and ultrasonographic examination, and thyroid function tests. RESULTS: Goiter was detected more frequently in the case group (P=0.001); such a finding, however, was not true for lower than normal urine iodine levels. The free T3 mean level was significantly lower in the case group compared to the control group (P=0.005). CONCLUSIONS: The higher prevalence of goiter rather than low levels of urinary iodine in gastric adenocarcinoma cases suggests that goiter, perhaps due to protracted but currently adjusted iodine deficiency, is more likely to be associated with gastric adenocarcinoma compared to the existing iodine deficiency itself.
Adenocarcinoma ; Autoimmune Diseases ; Goiter ; Halogenation ; Iodine ; Porphyrins ; Prevalence ; Stomach Neoplasms ; Thyroid Function Tests ; Thyroid Gland

OBJECTIVETo introduce synergetic inactivation of microorganisms in drinking water by short-term free chlorination for less than 15 minutes followed by monochloramination.

METHODSIndicator microorganisms such as Escherichia coli, Staphylococcus aureus, Candida albicans, and spores of Bacillus subtilis were used to assess the efficiency of sequential chlorination and free chlorination.

RESULTSThe sequential chlorination was more efficient in inactivating these microorganisms than free chlorination, indicating that synergy was provided by free chlorine and monochloramine. Ammonia addition time, temperature and pH had influences on this synergy.

CONCLUSIONSThe possible mechanism of this synergy might involve three aspects: free chlorine causing sublethal injury to microorganisms and monochloramine further inactivating them; different ability of free chlorine and monochloramine to penetrate and inactivate microorganism congeries; and higher concentration of residual chlorine in sequential chlorination than in free chlorination.

Chloramines ; chemistry ; pharmacology ; Chlorine ; chemistry ; Disinfection ; methods ; Halogenation ; Water ; chemistry ; Water Microbiology ; Water Purification ; methods

A study was carried out for purpose of grasping the status of bacteriological contamination of the public wells in Iri city, during the period from 1 to 15 August, 1974. Coliform groups were detected by membrane filter method and physical conditions of the well were checked. 1. The households which used the piped water occupied 70.8 per cent (11,907 households) out of total households Iri city. 2. Temperature of the well water was 38 out of 50 samples (72.0%) with 12.1 to 16.0 degrees C and 9 wells with 10.1 to 12.0 degrees C. 3. The pH values range of the well water was 6.0 to 7.9, 11 cases of 22.0 per cent less than 6.5 and 8 cases of 16.0 per cent more than 7.5. 4. The residual chlorine was found at 15 samples (30.0%) contained 0.1 to 0.5ppm, 9 samples (18.0%), 0.6 to 1.0 ppm after 24 hours of chlorination. 5. Coliform groups were found at 49 out of 50 samples (98.0%) before chlorination when 100ml well waters was tested by membrane filter technique and 15 wells(30.0%) were potable for drinking within 24 hours after chlorination. 6. Coliform groups positive were 23 out of 26 samples (88.5%) with no residual chlorine, 12 out of 16 samples (80.0%) with 0.1 to 0.5ppm and none out of 9 with 0.6 to 1.0ppm.
Chlorine ; Drinking ; Family Characteristics ; Halogenation ; Hand Strength ; Hydrogen-Ion Concentration ; Membranes ; Water

The thioureylene drugs, propylthiouracil and methylmercaptoimidazol(MMI), exert their antithyroid effect primarily through inhibition of thyroid peroxidase-catalyzed iodination of thyroglobulin. Recently the interest about the effect to the thyroglobulin synthesis of these drugs have been increasing. So we studied the MMI effect to the thyroglobulin synthesis in cultured porcine thyroid cells. Porcine thyroid cells were isolated by sequential trypsinization in the presence of EGTA, seeded at high density(1X10^6 cells/cm^2) and cultured. One week later, MMI was added in different concentrations(0, 0.2, 1, 5mM) with TSH only or with 4H(b-TSH, Insulin, Transferrin, Hydrocortisone) or without hormone. Medias were collected after 24 hours and compared the amount of thyroglobulin secreted. And also pulse-labeling were performed with S^35 cysteine/methionine(1-2uCi/well) for 30, 60, 90min at the same conditions.There was no significant change in the amount of the secreted thyroglobulin by MMI, and there was no significant change in the pulse-labeled interacellular thyroglobulin by MMI. And also there was no significant change in the secretion of TSH-stimulated thyroglobulin by MMI. So we conclude that MMI has no effect on the thyroglobulin synthesis in cultured porcine thyroid cells and also MMI has no effect on the TSH-stimulated thyroglobulin synthesis in cultured porcine thyroid cell.
Antithyroid Agents ; Egtazic Acid ; Halogenation ; Insulin ; Methimazole ; Propylthiouracil ; Thyroglobulin ; Thyroid Gland ; Transferrin ; Trypsin

A accidental spills of phenol(100%) to the river Nakdong with subsequent contamination of the tap water for about two million consumers in Taegu city of Korea were occurred in March 1991. A historical cohort study of 6,913 individuals was undertaken to determine the associated with illness. Population subjects were divided into two groups of exposed and unexposed. Exposed subjects were reported to be phenol associated symptoms significantly higher than those in a nearby unexposed area(39.6% vs 9.4%, p<0.01). Especially, in the related symptoms, highly significant differences were noted in the number of subjects reporting gastrointestinal illness such as nausea, vomiting, diarrhea, or abdominal pain. During the accident, study subjects who experienced peculiar taste or odor in the tap water were significantly higher in the exposed areas(92% vs 34.3%). Chlorophenols formed from chlorination of water may have aggravated the problem.
Abdominal Pain ; Chlorophenols ; Cohort Studies ; Daegu ; Diarrhea ; Drinking Water* ; Drinking* ; Equipment and Supplies* ; Halogenation ; Korea ; Nausea ; Odors ; Phenol* ; Rivers ; Vomiting ; Water

OBJECTIVES: N-Nitrosodimethylamine (NDMA) is classified as a probable human carcinogen by the United States Environmental Protection Agency (US EPA) and is formed during the chlorination of municipal drinking water. In this study, selected nitrosamines were measured in chlorinated drinking water collected from Chuncheon, Kangwon-do, Republic of Korea, and a risk assessment for NDMA was conducted. METHODS: Twelve water samples were collected from 2 treatment plants and 10 household taps. Samples were analyzed for 6 nitrosamines via solid-phase extraction cleanup followed by conversion to dansyl derivatives and high-performance liquid chromatography-fluorescence detection (HPLC-FLD). Considering the dietary patterns of Korean people and the concentration change of NDMA by boiling, a carcinogenic risk assessment from ingestion exposure was conducted following the US EPA guidelines. RESULTS: NDMA concentrations ranged between 26.1 and 112.0 ng/L. NDMA in water was found to be thermally stable, and thus its concentration at the end of boiling was greater than before thermal treatment owing to the decrease in water volume. The estimated excess lifetime carcinogenic risk exceeded the regulatory baseline risk of 10(-5). CONCLUSIONS: This result suggests that more extensive studies need to be conducted on nitrosamine concentration distributions over the country and the source of relatively high nitrosamine concentrations.
Dimethylnitrosamine ; Drinking ; Drinking Water ; Eating ; Family Characteristics ; Halogenation ; Humans ; Nitrosamines ; Oligopeptides ; Phosphatidylcholines ; Republic of Korea ; Risk Assessment ; United States Environmental Protection Agency ; Water

Polychlorinated biphenyls (PCBs) are persistent and bioaccumulative environmental pollutants. Recently, it is suggested that neurotoxic effects such as motor dysfunction and impairment in memory and learning have been associated with PCB exposure. However, structure relationship of PCB congeners with neurotoxic effects remains unknown. Since PKC signaling pathway is implicated in the modulation of motor behavior as well as learning and memory and the role of PKC are subspecies-specific, we attempted to study the effects of structurally distinct PCBs on the total PKC activity as well as subspecies of PKC in cerebellar granule cell culture model. Cells were exposed to 0, 25 and 50 microM of PCB-126, PCB-169, PCB-114, PCB-157, PCB-52 and PCB-4 for 15 min. Cells were subsequently analyzed by [3H] phorbol ester binding assay or immunoblotted against PKC-alpha and -epsilon monoclonal antibodies. While non-dioxin-like-PCB (PCB-52 and PCB-4) induced a translocation of PKC-alpha and -epsilon from cytosol to membrane fraction, dioxin-like PCBs (PCB-126, -169, -114, -157) had no effects. [3H] Phorbol ester binding assay also revealed structure-dependent increase similar to translocation of PKC isozymes. While PCB-4 induced translocation of PKC-alpha and -epsilon was inhibited by ROS inhibitor, the pattern of translocation was not affected in presence of AhR inhibitor. It is suggested that PCB-4-induced PKC activity may not be mediated via AhR-dependent pathway. Taken together, our findings suggest that chlorination of ortho-position in PCB may be a critical structural moiety associated with neurotoxic effects, which may be preferentially mediated via non-AhR-dependent pathway. Therefore, the present study may contribute to understanding the neurotoxic mechanism of PCBs as well as providing a basis for establishing a better neurotoxic assessment.
Antibodies, Monoclonal ; Cell Culture Techniques ; Cytosol ; Environmental Pollutants ; Halogenation ; Isoenzymes ; Learning ; Membranes ; Memory ; Neurons ; Phorbols ; Polychlorinated Biphenyls ; Protein Kinase C ; Protein Kinases ; Structure-Activity Relationship