Breast cancer inhibiting diastereomeric diacetato[1,2-bis(4-fluorophenyl)ethylenediamine]platinum(II) derivatives: synthesis and studies on the relationship between reactivity and antitumor activity

Antitumor active [1,2-bis(4-fluorophenyl)ethylenediamine]platinum(II) diastereoisomers containing acetic acid derivatives as ‘leaving groups’ (acetate: meso/rac-4F-Pt(Ac)₂; monochloroacetate: meso/rac-4F-Pt(ClAc)₂; dichloroacetate: meso/rac-4F-Pt(Cl₂Ac)₂; trichloroacetate: meso/rac-4F-Pt(Cl₃Ac)₂; glycolate: meso/rac-4F-Pt(OHAc)₂; phenylacetate: meso/rac-4F-Pt(PhAc)₂) were synthesized and characterized by IR and ¹H NMR spectroscopy. In all complexes except meso/rac-4F-Pt(PhAc)₂, which exist as [meso/rac-4F-PtPhAc]⁺PhAc⁻, both carboxylic acid residues are coordinated to platinum. Kinetic studies on the reaction behavior of the title compounds with nucleophiles were performed by using iodide as nucleophile. The studies show that the new complexes react with nucleophiles predominantly via the ‘solvent path’ (i.e. via the reactive intermediates = Pt(X)(OH₂)⁺ and =Pt(OH₂)₂²⁺. Therefore the rates of reactions in which the reactive species are formed affect the antitumor activity of the complexes as well as their inactivation by bionucleophiles during the transport to the tumor. The extent of accumulation in the tumor cell, too, influences the antitumor activity of a complex. The rate constants are discussed in view of the activities of the respective complexes on the human MCF-7 breast cancer cell line. From the title compounds the Cl₂Ac and Cl₃Ac derivatives do not come close to the standard cisplatin, neither in chemical reactivity nor in biological activity. Meso/rac-4F-Pt(Ac)₂ and meso/rac-4F-Pt(ClAc)₂, respectively, show similar hydrolysis rates but lower antitumor activities than cisplatin, presumably due to a reduced drug uptake by the tumor cell. Meso/rac-4F-Pt(PhAc)₂ compare well with their standard carboplatin in respect to both properties. Other than the remaining, poorly water soluble title compounds, meso/rac-4F-Pt(OHAc)₂ equal their standard cisplatin in terms of water solubility and antitumor activity rac-4F-Pt(OHAc)₂ > meso-4F--Pt(OHAc)₂). However, they are markedly faster hydrolyzed than cisplatin. By use of rac-4F-Pt(Ac)₂ as an example it was confirmed that, in contrast to the parent compound rac-4F-PtCl₂, the new complex type is also active under in vivo conditions owing to its markedly lower reactivity (mainly due to the lack of a direct substitution by strong nucleophiles), which entails a reduced inactivation of the drug on its way to the tumor. The in vitro testing on tumor cell lines combined with the evaluation of the water solubility and with kinetic studies on the reaction with nucleophiles is a useful method for the preselection of potent platinum complexes deserving further thorough in vitro and in vivo investigations.     

Male dominance rank and offspring-initiated affiliative behaviors were not predictors of paternity in a captive group of pigtail macaques (Macaca nemestrina)

Paternity of 16 pigtail macaque offspring was determined using a DNA profile analysis and was based on two independent assays of the genome of each individual using multilocus DNA probes. The offspring were members of a group of 59 pigtail macaques, including 5 adult males, 1 subadult male, and 37 adult and subadult females. Rank was unrelated to paternity as the first ranking male sired 0, the second ranking male sired 3; the third ranking male sired 0, the fourth ranking male sired 8, and the fifth ranking male sired 2 offspring. The subadult male sired 0 offspring. The DNA analysis was effective in excluding possible sires of 3 offspring whose mothers had become pregnant by another male before being introduced to the study males. Subsequent semen evaluation revealed an absence of sperm in the semen of the alpha male, but revealed a sperm count within normal limits in the third ranking male, who also sired no offspring. Behavioral data focusing on male-offspring interactions found that offspring did not preferentially affiliate with their sire and that males did not affiliate with their offspring frequently enough for analysis. Thus, this study of one captive pigtail macaque group demonstrates that: (1) rank was not a predictor of reproductive success; and (2) there was no preferential attraction for one's own offspring by males or one's own sire by offspring.     

Short-Term In Vitro Culture and Molecular Analysis of the Microsporidian, Enterocytozoon bieneusi

ABSTRACT. The microsporidium, Enterocytozoon bieneusi , causes a severe, debilitating, chronic diarrhea in patients with the acquired immunodeficiency syndrome. Specific diagnosis of intestinal microsporidiosis, especially due to Enterocytozoon , is difficult and there is no known therapy that can completely eradicate this parasite. Preliminary studies indicate that a short term (about 6 months) in vitro culture of this parasite yielding low numbers of spores, may be established by inoculating human lung fibroblasts and/or monkey kidney cell cultures with duodenal aspirates and or biopsy from infected patients. The cultures may subsequently be used for the isolation and molecular analysis of parasite DNA.     

Gram-Chromotrope: a New Technique that Enhances Detection of Microsporidial Spores in Clinical Samples

We have developed a new staining procedure that combines the traditional Gram staining for bacteria and the Weber's chromotrope staining method, the standard technique for the detection of microsporidia spores in clinical Specimens. This “Gram-chromotrope” staining technique enhances the staining characteristics of microsporidia spores and facilitates the easy detection and differentiation of spores from other microorganisms that are found in clinical specimens, especially stool samples. This new technique is fast, reliable, and simple to perform, and can be easily adapted for use in clinical laboratories.     

Hierarchical genetic structure and gene flow in three sympatric species of Amazonian rodents

The population genetic structure of three species of Amazonian rodents ( Oligoryzomys microtis, Oryzomys capito , and Mesomys hispidus ) is examined for mtDNA sequence haplotypes of the cytochrome b gene by hierarchical analysis of variance and gene flow estimates based on fixation indices ( N _ST) and coalescence methods. Species samples are from the same localities along 1000 km of the Rio Juruá in western Amazonian Brazil, but each species differs in important life history traits such as population size and reproductive rate. Average haplotype differentiation, hierarchical haplotype apportionment, and gene flow estimates are contrasted in discussing the current and past population structure. Two species exhibit isolation by distance patterns wherein gene flow is largely limited to geographically adjacent localities. Mesomys exhibits this pattern throughout its range along the river. More than 75% of haplotype variation is apportioned among localities and regions, and estimates of Nm for pair-wise comparisons are nearly always less than 1. Oligoryzomys shows weak isolation by distance, but only over the largest geographical distances. Nm values for this species are nearly always above 1 and most (about 80%) of haplotype variation is contained within local populations. In contrast, Oryzomys exhibits no genetic structure throughout its entire distribution; Nm values average 17 and nearly 90% of the total haplotype variance is contained within local populations. Although gene flow estimates are high, the pattern of Nm as a function of geographical distance suggests that this species experienced a more recent invasion of the region and is still in genetic disequilibrium under its current demographic conditions.     

Phylogenetic relationships among marsupial frog genera (Anura: Hylidae: Hemiphractinae) based on evidence from morphology and natural history

We reassess the phylogenetic relationships of genera of hemiphractine hylid frogs (Marsupial Treefrogs) and discuss the evolution of several distinctive characters within this group using parsimony analysis. Fifty-one morphological and life-history characters were sampled from two species of Cryptobatrachus , three species of Flectonotus , 17 species of Gastrotheca , all five species of Hemiphractus , and one species of Stefania as the ingroup and three hyline, one phyllomedusine, and one pelodryadine species as outgroups. Our results support the mon-ophyly of Flectonotus, Cryptobatrachus , and Hemiphractus. Gastrotheca is paraphyletic with respect to Hemiphractus , dorsal pouches were lost in the ancestor of Hemiphractus. Direct development is a synapomorphy for Hemiphractinae and tadpoles were regained independently several times. These results stand in stark contrast to the prevailing paradigm regarding marsupial frog relationships.     

The effects of Anabaena spiroides (Cyanophyceae) exopolysaccharide on copper toxicity to Simocephalus serrulatus (Cladocera, Daphnidae)

1. This work investigated the consumption of a microalgal (Anabaena spiroides) exopolysaccharide by the cladoceran Simocephalus serrulatus (Cladocera, Daphnidae) and its effect on copper toxicity. 2. Total organic carbon concentration was used to quantify the microalgal exopolysaccharide. Both copper‐complexed exopolysaccharides and copper‐free exopolysaccharides were taken up by S. serrulatus. 3. A reduction of free copper ions was obtained in the presence of A. spiroides exopolysaccharide. Copper toxicity (EC₅₀) and zooplankton concentrations were inversely correlated to exopolysaccharide concentration in experimental media. 4. An increase of free copper ions in experimental media was obtained after exopolysaccharide consumption, suggesting that S. serrulatus excreted copper to the surrounding environment.     

锁阳和肉苁蓉寄生方式的区别

锁阳和肉苁蓉都是中医药里重要的补益类药材,但由于过度采挖和采挖方式不当,目前它们的野生资源已濒临枯竭。肉苁蓉和锁阳分别是我国濒危和易危珍稀植物,研究二者寄生方式的特点与区别不仅可以促进锁阳和肉苁蓉的人工栽培,从而使野生药材得到一定的保护,而且对了解寄生植物在荒漠地区等极端严酷环境中的适应机制具有重要的生态学意义。该研究采用形态学观察结合常规石蜡切片法,对锁阳和肉苁蓉分别在各自寄主植物上的寄生方式进行了研究。结果表明：(1)锁阳的营养繁殖体在寄主植物根部呈串状分布,与寄主植物的连接方式属于非末端寄生;锁阳的吸器侵入寄主根系韧皮部和木质部的一部分区域,但是韧皮部和木质部大部分区域未被锁阳吸器占据,即有部分营养物质被锁阳“截取”。(2)肉苁蓉在其肉质茎基部长出新的芽体,与寄主植物的连接方式属于末端寄生;肉苁蓉的吸器侵入寄主根韧皮部和木质部全部区域。因此,锁阳寄生后,被寄生的寄主根依然能够向前生长,具有正常的功能;肉苁蓉寄生后,寄生点的寄主根失去根系的正常功能,成为一个为肉苁蓉生长发育提供营养物质的“输送通道( Transport channel)”。