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21.
The influence of stereoisomerism on the pharmacokinetics of Tc mono-oxo complexes is reviewed. Tc(V) monooxo complexes formed with N/S ligands have four donor groups from the ligands in an equatorial plane; the oxo ligand coordinates in an axial position. Stereoisomerism in Tc (V) mono-oxo complexes can be centered within the ligand (carbon atom in the chelate ring or ligating nitrogen of amine donors) or at the Tc. The metal center becomes chiral when an equatorial ligand has a head and a tail (i.e., the two ends of the ligand differ). All types of stereocenters can produce significantly different pharmacokinetic profiles for individual isomers. Thus, biological evaluation of separated stereoisomers is necessary to identify the optimal sterochemical configuration, particularly for radiopharmaceuticals targeted to receptor molecules with low specificity. Because of interspecies variation, there is ultimately no substitute for human testing. Although it is possible that the increase in non-specific binding of agents incorporating L-vs D-amino acids may more than offset any increased receptor binding, much more information is needed. Stereochemical factors can also lead to unpredictable differences in coordination geometry and thermodynamic preference of a single isomer; thus chemical characterization of stereoisomers continues to be an important component of radiopharmaceutical development. 相似文献
22.
This study examined the contribution of individual and family factors to psychological adjustment in a sample of junior high school students living in urban poverty. Identity development and perceived parental treatment were hypothesized to serve as mediating, or protective, factors between economic hardship and levels of self-esteem, depression, and loneliness. Consistent with the hypotheses, identity development did serve as a mediator between poverty and psychological adjustment. While perceived parental treatment was not related to economic hardship, it was clearly associated with well-being in this sample. Findings are discussed in terms of the differing contributions of family and individual development, as well as the importance of mediators in assessing the effects of poverty on young adolescents. 相似文献
23.
Mercaptoacetyltriglycine forms complexes with (186/188)Re and (99m)Tc radionuclides that are useful in nuclear medicine because they are substrates of the renal anion transport system. However, the renal clearance of [MO(MAG(3))](2-)(MAG(3) = penta-anionic form of mercaptoacetyltriglycine, M = Re, Tc) complexes are less than ideal. Organic sulphonates are also transported by the renal anion transport system and phosphonates are similar to sulphonates in size and shape. In an effort to develop new ligands that form Re and Tc complexes and have improved renal clearances compared to [MO(MAG(3))](2-) complexes, the sulphonate and phosphonate derivatives of mercaptoacetyltriglycine were synthesized. The dianion [ReO(MAG(2)-AMS)](2-) (MAG(2)-AMS = penta-anionic form of mercaptoacetylglycylglycylaminomethanesulphonic acid) was prepared for characterization by exchange reaction of ReOCl(3)(Me(2)S)(OPPh(3)) and isolated as the disodium salt. The structure of Na(2)[ReO(MAG(2)-AMS)].3H(2)O (6) was determined by X-ray diffraction. The coordination geometry is pseudo square pyramidal, with the nitrogen and sulfur donor atoms forming a square base and the oxo ligand at the apex. The deprotonated sulphonate group has a syn conformation with respect to the oxo ligand. The renal clearances of [(99m)TcO(MAG(2)-AMS)](2-) and [(99m)TcO(MAG(2)-AMP)](3-) were similar in rats and suggest that the difference in total charge between the SO(3) (-) and PO(3) (2-) groups is not important to renal clearance. However, their renal clearances were 40-50% less than that of [(99m)TcO(MAG(3))](2-) suggesting that the size and shape of the large tetrahedral SO(3) (-) and PO(3) (2-) groups of [(99m)TcO(MAG(2)-AMS)](2-) and [(99m)TcO(MAG(2)-AMP)](3-) inhibit recognition by the renal transport system compared to the small planar CO(2) (-) group of [(99m)TcO(MAG(3))](2-). 相似文献
24.
GN Kremenchutski? ML Gorbunova LG Iurgel' VI Chu?ko SA Cherniaev 《Canadian Metallurgical Quarterly》1994,56(4):36-42
The paper deals with the data on biology of Aerococcus, a slightly studied group of microorganisms. Physiological-biochemical properties of Aerococcus are described, data of their distribution in nature are given. Peculiar attention is paid to the estimate of the role of Aerococcus in human microbiocenoses. As a result of the profound and all-round study of this group of microorganisms the authors have developed new bacterial drug "A-bakterin" based on the aerococcus strain. Data presented about the results of clinical tests of "A-bakterin" are presented, a possibility to use Aerococcus lysate in the elaboration of new drugs is discussed. 相似文献
25.
P Brown L Cervenáková L McShane LG Goldfarb K Bishop F Bastian J Kirkpatrick P Piccardo B Ghetti DC Gajdusek 《Canadian Metallurgical Quarterly》1998,50(3):684-688
A 53-year-old man died of sporadic Creutzfeldt-Jakob disease (CJD) after a 1.5-year clinical course. Four and a half years later, his then 55-year-old widow died from CJD after a 1-month illness. Both patients had typical clinical and neuropathologic features of the disease, and pathognomonic proteinase-resistant amyloid protein ("prion" protein, or PrP) was present in both brains. Neither patient had a family history of neurologic disease, and molecular genetic analysis of their PrP genes was normal. No medical, surgical, or dietary antecedent of CJD was identified; therefore, we are left with the unanswerable alternatives of human-to-human transmission or the chance occurrence of sporadic CJD in a husband and wife. 相似文献
26.
Three projective personality tests were used to assess attitude to aggression (The Identification Test), anxiety and defenses (The Meta-Contrast Technique) and creative functioning (The Creative Functioning Test) in 70 patients with breast cancer. Discriminant analyses were applied pro primo to characterize psychologically patients with a better prognosis and patients with a poorer prognosis. A second aim was to characterize psychologically older (postmenopausal) and younger (premenopausal) women. Generally, high scores on the Identification Test indicated maladaptive attitudes towards aggression among all the patients. Patients with a poorer prognosis showed responses that in healthy subjects indicate acknowledgement of aggressive impulses, perhaps suggesting lack of "defenses" against such impulses among those patients. Another way to describe it would be that patients with a better prognosis seem to have (normally nonadaptive) "defenses" against aggressive impulses while those with poorer prognosis have not. Surprisingly, the patients with a better prognosis (but not those with a poorer prognosis) gave responses classified as depression in the Meta-Contrast Technique. Typical of premenopausal patients were responses classified as anxiety as well as reaction formation on the Identification Test. Responses classified as adaptive defenses (isolation) were seen in the Meta-Contrast Technique. A surprising finding was that many of these patients were characterized by high scores on the creativity test. These original statistically significant findings of attitudes towards aggression and creative functioning in breast cancer patients are discussed in relation to the underlying nature of aggression and creativity. 相似文献
27.
IA Andriashvili RSh Adamiia LI Kvachadze TG Melitauri LG Pataridze 《Canadian Metallurgical Quarterly》1977,42(2):300-305
The composition of nitrous bases of phage FI-1 DNA was studied. As is evidenced from the values of buoyant density in CsCl (p=1,7093 g/cm(3)), melting temperature (T degrees m=86,05 degrees), spectral parameters and direct chromatographic determination, the DNA analysed contains 41,5 mole% pairs of guanine-cystosine. 5-hydroxymethylcytosine and other anomalous bases were not found. Chemical identification and jaxtposition of data of buoyant density in CsCl and Cs2SO4 (p=1,4466 g/cm(3)) and T degrees m. showed the presence of the extra-sugar component in DNA, most likely in the form of hentibiose. Spectral character of thermal denaturation of DNA in different solvents is indicative of the double helixity of its structure. DNA is characterized by enthalpies of conformational transitions "helix coil" (deltaH=12,3 kcal/g) and (deltaH=10 kcal/g) for the solvents, 1 x SSC, and 0,1 x SSC, correspondingly. The presence of extra-sugar in DNA with standard set of nitrous bases is discussed. 相似文献
28.
The trial record in an antitrust case against the Oregon State Medical Society, finally decided in 1952, was examined to reconstruct the behavior of a competitive market for health insurance coverage. Health insurers, called "hospital associations," were found to have engaged individually in cost-control efforts similar to, but possibly more aggressive than, today's utilization review under professional sponsorship. The subsequent disappearance of these insurer-initiated cost controls in Oregon is traced to the medical society's organization of a competing Blue Shield plan as a model of insurer conduct and to a simultaneous boycott by physicians of the hospital associations as long as they persisted in questioning doctors' practices. Some modern parallels are noted, and the advantages of fostering privately sponsored cost-control efforts are suggested. 相似文献
29.
LG Kupchinski? IuA Barshte?n BG Pogodaev AI Treshinski? 《Canadian Metallurgical Quarterly》1976,(3):80-84
A study was made of a possibility of using Soviet made membranes "Vladipor" with a pore diameter of 16--17 nm for the purpose of concentration and purification of antigenic extracts from stab cultures of S. typhi obtained by the action of typsin, hydrogen peroxide and detergents. Preparations, complete by antigenic structure, were obtained by ultrafiltration, with a good yield. The maximal rate of ultrafiltration was noted in case of "peroxide" antigenic preparations. The use of diafiltration provided a significant reduction of the ash content in the end products. 相似文献
30.