Urban bioclimatology

This article deals with the part of urban climatology which is of particular relevance to human beings. Presented first is a summary of all human biometeorologically effective complexes, as well as other factors which are relevant to urban planning and which depend on atmospheric conditions in urban structures in a direct or indirect manner. Later, methods for human biometeorologically significant assessment of thermal and air pollution components of the urban climate are discussed in detail, because these components can be strongly influenced by urban planning. The application of these methods is illustrated by some results of appropriate investigations in urban areas.     

Synthetic activities of mass cultures and clones of human gingival fibroblasts

The percentage of synthesis dedicated to collagen is elevated in low-density cultures of human gingival fibroblasts, as is per-cell total protein synthetic activity and glycosaminoglycan accumulation. These observations can be explained, in part, by a decrease in membrane transport of precursor substance in high-density cultures. Synthetic activity by human fibroblasts can be reliably assayed in vitro using as few as 500 cells sparsely seeded. Such low-cell number assay is essential for study of single-cell clones, where replicative life span is limited.     

便携式生命探测仪的研究

生命的无损检测技术是以人体特性为基础,通过研究电磁波束照射人体而反射信号的波形规律,了解人体受到微动所调制而使得回波信号的某些参数的变化特性,从而提取出人体生命参数。描述了以DSP＆FPGA为核心构造的人体信号的探测装置的研究。通过回波的频率和相位特性分析,确定了生命信号检测系统的最佳参数。在此基础上设计了一套便携式生命探测仪,硬件系统主要由DSP处理器、LCD图形显示器、雷达电磁波单元等组成。软件系统由信号处理算法模块、显示模块、信号发射与接收模块等构成。     

Differences in cardiac myosin light chain LC1 among human,monkey and sheep

Summary The atrial and ventricular myosin light chains of human, monkey and sheep hearts were compared by dodecylsulfate polyacrylamide gel electrophoresis. The atrial light chain 2 and ventricular light chain 2 are similar among these mammals. However, the atrial light chain 1 of monkey has different electrophoretic mobility from those of human and sheep. The monkey ventricular light chain 1 has same mobility as that of sheep but different from that of human.Acknowledgments. This work was supported by MRC of Canada No. MA-8559. Dr G. Jackowski is a scholar of the Medical Research Council of Canada, and is the author to whom all correspondence should be addressed.     

Molecular dialogue between the human gut microbiota and the host: a Lactobacillus and Bifidobacterium perspective

The human gut represents a highly complex ecosystem, which is densely colonized by a myriad of microorganisms that influence the physiology, immune function and health status of the host. Among the many members of the human gut microbiota, there are microorganisms that have co-evolved with their host and that are believed to exert health-promoting or probiotic effects. Probiotic bacteria isolated from the gut and other environments are commercially exploited, and although there is a growing list of health benefits provided by the consumption of such probiotics, their precise mechanisms of action have essentially remained elusive. Genomics approaches have provided exciting new opportunities for the identification of probiotic effector molecules that elicit specific responses to influence the physiology and immune function of their human host. In this review, we describe the current understanding of the intriguing relationships that exist between the human gut and key members of the gut microbiota such as bifidobacteria and lactobacilli, discussed here as prototypical groups of probiotic microorganisms.     

Endogenous animal toxin-like human β-defensin 2 inhibits own K<Superscript>+</Superscript> channels through interaction with channel extracellular pore region

Human potassium channels are widely inhibited by peptide toxins from venomous animals. However, no human endogenous peptide inhibitor has been discovered so far. In this study, we demonstrate for the first time using electrophysiological techniques, that endogenous human β–defensin 2 (hBD2) is able to selectively and dose-dependently inhibit the human voltage-gated Kv1.3 channel at picomolar peptide concentration. The co-immunoprecipitation assays further supported the selective binding of hBD2 to Kv1.3 channel. Using mutagenesis experiments, we found that the outer pore domain of Kv1.3 channel was the binding site of hBD2, which is similar to the interacting site of Kv1.3 channel recognized by animal toxin inhibitors. The hBD2 was able to suppress IL-2 production through inhibition of Kv1.3 channel currents in human Jurkat cells, which was further confirmed by the lack of hBD2 activity on IL-2 production after Kv1.3 knockdown in these cells. More interestingly, hBD2 was also found to efficiently inhibit Kv1.3 channel currents and suppress IL-2 production in both human primary CD3⁺ T cells and peripheral mononuclear cells from either healthy donors or psoriasis patients. Our findings not only evidenced hBD2 as the first characterized endogenous peptide inhibitor of human potassium channels, but also paved a promising avenue to investigate newly discovered function of hBD2 as Kv1.3 channel inhibitor in the immune system and other fields.     

Some properties of external NADH oxidation by human placental mitochondria.

Isolated human term placenta mitochondria catalyse oxidation of external NADH in the presence of cytochrome c. This reaction is insensitive to the respiratory chain inhibitors such as rotenone and antimycin A, and is not coupled to phosphorylation. Comparison of the effect of Mg++ ion on NADH plus cytochrome c oxidation by human term placental, human skeletal muscle and rat skeletal mitochondria showed that Mg++ ion exerts an inhibitory effect in the case of human mitochondria and a stimulatory effect in the case of rat skeletal muscle mitochondria.     

Effect of piperazine on the level of phospholipids and on the activities of certain enzymes of phospholipid metabolism in human Ascaris lumbricoides.

The phospholipid level in the human parasitic nematode Ascaris lumbricoides is decreased by piperazine, by partially stimulating catabolic enzymes such as phospholipase C and partially inhibiting anabolic enzymes such as choline kinase.     

Platelet monoamine oxidase B: use and misuse

The human platelet in addition to having serotonin (5-HT) receptors, uptake carriers (receptor) and transmitter storage vesicles, primarily possesses mitochondrial monoamine oxidase (MAO) type B. Similar to the major form of MAO in the human brain, this enzyme actively oxidizes A-B and B substrates (tyramine, dopamine, phenylethylamine) as well as the novel secondary amine anticonvulsant, milacemide and dopaminergic neurotoxin, MPTP. 5-HT oxidation is hardly affected by the platelet enzyme and MAO inhibitors have no net effect on its accumulation. MAO-B is selectively inhibited by 1-deprenyl and thus the platelet enzyme may be useful to monitor the anti-Parkinson activity of such drugs, as related to their ability to inhibit brain MAO-B. The oxidation of the anticonvulsant, milacemide, to glycine in vitro and in vivo by MAO-B, may herald new prospects for the development of inert prodrugs capable of being metabolized to neuroactive substances by MAO-B. The plasma levels of their metabolites may be an index of MAO-B activity found in the platelet and brain.     

Some properties of external NADH oxidation by human placental mitochondria

Summary Isolated human term placenta mitochondria catalyse oxidation of external NADH in the presence of cytochrome c. This reaction is insensitive to the respiratory chain inhibitors such as rotenone and antimycin A, and is not coupled to phosphorylation. Comparison of the effect of Mg⁺⁺ ion on NADH plus cytochrome c oxidation by human term placental, human skeletal muscle and rat skeletal mitochondria showed that Mg⁺⁺ ion exerts an inhibitory effect in the case of human mitochondria and a stimulatory effect in the case of rat skeletal muscle mitochondria.This work has been supported by a grant from Ministry of Higher Education Science and Technology within the project No. 01.02.     

Platelet monoamine oxidase B: Use and misuse

The human platelet in addition to having serotonin (5-HT) receptors, uptake carriers (receptor) and transmitter storage vesicles, primarily possesses mitochondrial monoamine oxidase (MAO) type B. Similar to the major form of MAO in the human brain, this enzyme actively oxidizes A-B and B substrates (tyramine, dopamine, phenylethylamine) as well as the novel secondary amine anticonvulsant, milacemide and dopaminergic neurotoxin, MPTP. 5-HT oxidation is hardly affected by the platelet enzyme and MAO inhibitors have no net effect on its accumulation. MAO-B is selectively inhibited by 1-deprenyl and thus the platelet enzyme may be useful to monitor the anti-Parkinson activity of such drugs, as related to their ability to inhibit brain MAO-B. The oxidation of the anticonvulsant, milacemide, to glycine in vitro and in vivo by MAO-B, may herald new prospects for the development of inert prodrugs capable of being metabolized to neuroactive substances by MAO-B. The plasma levels of their metabolites may be an index of MAO-B activity found in the platelet and brain.     

The chloride effect in human hemoglobin: A new kind of allosteric mechanism

In human hemoglobin hydrogen ions, chloride, 2,3-diphosphoglycerate and CO₂ cooperate to shift the oxygen equilibrium curve to the right. Bovine hemoglobin, by contrast, has an intrinsically low oxygen affinity: when stripped, it is as low as that of human hemoglobin in the presence of 0.1 M NACl+0.1 M DPG.     

Chromatin ofh regions of human chromosomes at high resolution

Summary Segmentation of the secondary constriction region (h) of human chromosomes 1, 9 and 16 is demonstrated by a high resolution banding technique. Based on these staining properties, it is suggested that the composition of theh region in human chromosomes is heterochromatic as well as euchromatic.     

The formation of disulfide bonds in human protamines during sperm maturation.

The disulfide contents of human sperm heads, as measured by reduction to the sulfhydryls and subsequent alkylation with 14C-iodoacetamide, increase about 2-fold during the sperm passage from the caput to caudal epididymides. Majority of the increased disulfides resides in the human protamine fractions.     

Welcome the Family of FANCJ-like Helicases to the Block of Genome Stability Maintenance Proteins

The FANCJ family of DNA helicases is emerging as an important group of proteins for the prevention of human disease, cancer, and chromosomal instability. FANCJ was identified by its association with breast cancer, and is implicated in Fanconi Anemia. Proteins with sequence similarity to FANCJ are important for maintenance of genomic stability. Mutations in genes encoding proteins related to FANCJ, designated ChlR1 in human and Chl1p in yeast, result in sister chromatid cohesion defects. Nematodes mutated in dog-1 show germline as well as somatic deletions in genes containing guanine-rich DNA. Rtel knockout mice are embryonic lethal, and embryonic stem cells show telomere loss and chromosomal instability. FANCJ also shares sequence similarity with human XPD and yeast RAD3 helicases required for nucleotide excision repair. The recently solved structure of XPD has provided new insight to the helicase core and accessory domains of sequence related Superfamily 2 helicases. The functions and roles of members of the FANCJ-like helicase family will be discussed. Received 17 September 2008; received after revision 24 October 2008; accepted 28 October 2008     

Novel vesicular extrusions during cell spreading

Summary During the late stages of cell spreading in vitro, the cells extrude a vesicular material into the medium. This phenomenon was observed in human glia and glioma cells as well as in human diploid fibroblasts MRC-5 and WI-38 cells. This extrusion of vesicular material is inhibited by cytochalasin-B and colcemid suggesting the involvement of microfilaments and microtubules and the active nature of this event. It appears that the cells may be excreting damaged surface components by a mechanism similar to patching, capping and endocytosis.     

Differential sensitivity to photohemolysis of erythrocytes enriched with some liposome-carried substances

The sensitivity of human erythrocytes to photohemolysis sensitized by addition of protoporphyrin IX can be selectively affected by their enrichment with substances carried by cationic liposomes. In particular the enrichment which superoxide dismutase is accompanied by a copper-related greater sensitivity toward photohemolysis, as observed in the Down's syndrome (mongolism). Instead it is possible to protect the erythrocytes against the phototoxic effect of protoporphyrin by enrichment with small amounts of beta-carotene.