Difference spectrum distortion in non-homogeneous pigment associations: Abnormal phytochrome spectra in vivo

Difference spectra for phototransformation of phytochrome in vivo may vary considerably in shape, in peak position and in the ratio of the heights of red to far-red peaks. Assuming non-homogeneous distributions of pigments, spectra could be calculated for a number of models of plant cells containing both phytochrome and chlorophyll. Some models satisfactorily account for the observed spectra and provide some information about the intracellular pigment distribution. The theory may also find application in the interpretation of difference spectra of other naturally occurring pigment associations.     

Synthesis and biological properties of substituted 1,4-dihydro-5-methyl-4-oxo-3-quinolinecarboxylic acids

A series of substituted 1-cyclopropyl-6-fluoro-1,4-dihydro-5-methyl-4-oxo-3-quinoline carboxylic acids was synthesized and tested for their in vitro and in vivo antibacterial activity. The introduction of a methyl group at the 5-position of quinoline nucleus enhanced characteristically the antibacterial activity against Gram-positive bacteria, including Streptococcus pneumonia, which is a major pathogen in the respiratory tract infection, while retaining Gram-negative activity. Among them, 1-cyclopropyl-6-fluoro-1,4-dihydro-5-methyl-7-(3-methyl-1-piperazinyl)-4-oxo-3-quinolinecarboxylic acid hydrochloride (grepafloxacin) exhibited potent in vitro antibacterial activity against Gram-positive bacteria such as Streptococcus pneumoniae and high in vivo efficacy on the experimental systemic infections caused by the Gram-positive and -negative bacteria tested. It also showed a high distribution to the lung and bronchoalveolar lavage fluid in comparison to reference drugs and is now undergoing clinical evaluation.     

Highly selective inhibition of estrogen biosynthesis by CGS 20267, a new non-steroidal aromatase inhibitor

CGS 20267 is a new non-steroidal compound which potently inhibits aromatase in vitro (IC₅₀ of 11.5 nM) and in vivo (ED₅₀ of 1–3 μg/kg p.o.). CGS 20267 maximally inhibits estradiol production in vitro in LH-stimulated hamster ovarian tissue at 0.1 μM with an IC₅₀ of 0.02 μM and does not significantly affect progesterone production up to 350 μM. In ACTH-stimulated rat adrenal tissue in vitro, aldosterone production was inhibited with an IC₅₀ of 210 μM (10,000 times higher than the IC₅₀ for estradiol production); no significant effect on corticosterone production was seen at 350 μM. In vivo, in ACTH-treated rats, CGS 20267 does not affect plasma levels of corticosterone or aldosterone at a dose of 4 mg/kg p.o. (1000 times higher than the ED₅₀ for aromatase inhibition in vivo). In adult female rats, a 14-day treatment with 1 mg/kg p.o. daily, completely interrupts ovarian cyclicity and suppresses uterine weight to that seen 14 days after ovariectomy. In adult female rats bearing estrogen-dependent DMBA-induced mammary tumors, 0.1 mg/kg p.o. given daily for 42 days caused almost complete regression of tumors present at the start of treatment. Thus compared to each other, CGS 16949A and CGS 20267 are both highly potent in inhibiting estrogen biosynthesis in vitro and in vivo. The striking difference between them is that unlike CGS 16949A, CGS 20267 does not affect adrenal steroidogenesis in vitro or in vivo, at concentrations and doses several orders of magnitude higher than those required to inhibit estrogen biosynthesis.     

Translating tissue culture results into animal models: the case of Salmonella typhimurium

Investigators use both in vitro and in vivo models to better understand infectious disease processes. Both models are extremely useful in research, but there exists a significant gap in complexity between the highly controlled reductionist in vitro systems and the largely undefined, but relevant variability encompassing in vivo animal models. In an effort to understand how Salmonella initiates disease at the intestinal epithelium, in vitro models have served a useful purpose in allowing investigators to identify molecular mechanisms responsible for Salmonella invasion of host cells and stimulation of host inflammatory responses. Identification of these molecular mechanisms has generated hypotheses that are now being tested using in vivo models. Translating the in vitro findings into the context of an animal model and subsequently to human disease remains a difficult challenge for any disease process.     

黑木耳黑色素对急性肝损伤的改善作用

黑色素是一种广泛存在于动物、植物、细菌及真菌中的生物色素,具有多种生物功能及良好的生物活性。黑木耳以“黑”出名,其富含的黑色素具有广阔开发应用价值。本研究旨在评价黑木耳黑色素对急性肝损伤的改善作用。首先应用傅里叶红外光谱初步对提取的黑木耳黑色素进行鉴定,再通过DPPH自由基及羟基自由基清除实验证实提取的黑木耳黑色素体外抗氧化能力,并进一步以四氯化碳致小鼠急性肝损伤为模型,通过检测血清酶指标、肝功指标的变化及病理切片情况,来评价黑木耳黑色素体内抗氧化及保肝效果。结果表明,提取的黑木耳黑色素具有黑色素特征的官能团结构和良好的体外抗氧化能力,对DPPH自由基和羟基（OH）自由基清除的EC₅₀分别为0.0887mg/mL、2.2030mg/mL;动物体内实验中,与模型组对比,给药组（黑木耳黑色素）的小鼠血清中ALT、AST含量显著降低（P<0.01）,肝脏中MDA含量显著降低（P<0.01）和SOD活性显著升高（P<0.01）,并且肝细胞病理状态明显改善。本文报道了黑木耳黑色素在体内能有效改善四氯化碳诱导的小鼠肝损伤,为黑木耳的功能产品开发提供了新思路和研究基础。     

Comparison of the effects of CRF and stress on levels of pituitary cyclic AMP and plasma ACTH in vivo

We have previously reported that acute stress increases levels of rat pituitary cyclic AMP in vivo. The present study was conducted to test the hypothesis that stress-induced increases in pituitary cyclic AMP in vivo were mediated via CRF. We compared the effects of various stressors with the effects of CRF or epinephrine administration on pituitary cyclic AMP and plasma ACTH responses in vivo. Stressors, epinephrine or CRF increased levels of pituitary cyclic AMP. Pituitary cyclic AMP response to either immobilization or CRF was much greater at light onset than at lights off in rats maintained on at 12 hr light: 12 hr dark lighting regimen. In rats with pituitary stalk transections, footshock did not increase levels of pituitary cyclic AMP, suggesting that some factor of central origin was required for this stress response. Exogenous CRF administration did increase levels of pituitary cyclic AMP in stalk-transected rats, while epinephrine increased levels in sham-operated but not in stalk-transected rats. Antisera to CRF markedly decreased pituitary cyclic AMP response to exogenous CRF administered 6 min following antisera and partially attenuated pituitary cyclic AMP response to forced running. Taken as a whole these data support a major role for CRF in the pituitary cyclic AMP response to stress.     

Noninvasive in vivo cell tracking using molecular imaging: A useful tool for developing mesenchymal stem cell-based cancer treatment

Mounting evidence has emphasized the potential of cell therapies in treating various diseases by restoring damaged tissues or replacing defective cells in the body. Cell therapies have become a strong therapeutic modality by applying noninvasive in vivo molecular imaging for examining complex cellular processes, understanding pathophysiological mechanisms of diseases, and evaluating the kinetics/dynamics of cell therapies. In particular, mesenchymal stem cells (MSCs) have shown promise in recent years as drug carriers for cancer treatment. They can also be labeled with different probes and tracked in vivo to assess the in vivo effect of administered cells, and to optimize therapy. The exact role of MSCs in oncologic diseases is not clear as MSCs have been shown to be involved in tumor progression and inhibition, and the exact interactions between MSCs and specific cancer microenvironments are not clear. In this review, a multitude of labeling approaches, imaging modalities, and the merits/demerits of each strategy are outlined. In addition, specific examples of the use of MSCs and in vivo imaging in cancer therapy are provided. Finally, present limitations and future outlooks in terms of the translation of different imaging approaches in clinics are discussed.     

Glycyrrhizae Radix attenuates peroxynitrite-induced renal oxidative damage through inhibition of protein nitration

We investigated the protective effects of Glycyrrhizae Radix extract against peroxynitrite (ONOO^-)-induced oxidative stress under in vivo as well as in vitro conditions. The extract showed strong ONOO^- and nitric oxide (NO) scavenging effects under in vitro system, in particular higher activity against ONOO^-. Furthermore, elevations of plasma 3-nitrotyrosine levels, indicative of in vivo ONOO^- generation and NO production, were shown using a rat in vivo ONOO^--generation model of lipopolysaccharide injection plus ischemia-reperfusion. The administration of Glycyrrhizae Radix extract at doses of 30 and 60 mg/kg body weight/day for 30 days significantly reduced the concentrations of 3-nitrotyrosine and NO and decreased inducible NO synthase activity. In addition, the nitrated tyrosine protein level and myeloperoxidase activity in the kidney were significantly lower in rats given Glycyrrhizae Radix extract than in control rats. However, the administration of Glycyrrhizae Radix extract did not result in either significant elevation of glutathione levels or reduction of lipid peroxidation in renal mitochondria. Moreover, the in vivo ONOO^- generation system resulted in renal functional impairment, reflected by increased plasma levels of urea nitrogen and creatinine, whereas the administration of Glycyrrhizae Radix extract reduced these levels significantly, implying that the renal dysfunction induced by ONOO^- was ameliorated. The present study suggests that Glycyrrhizae Radix extract could protect the kidneys against ONOO^- through scavenging ONOO^- and/or its precursor NO, inhibiting protein nitration and improving renal dysfunction caused by ONOO^-.     

-alkoxyphenol leukotriene B4 receptor antagonists: effect of a chroman carboxylic acid.

Several -alkoxyphenols containing a chroman carboxylic acid sidechain have been prepared as antagonists of leukotriene B₄ receptors. These antagonists were compared to their parent alkoxyphenols containing the tetrazole acid sidechain. These chroman containing antagonists retained their binding potency for human neutrophil receptors; however, showed enhanced potency against guinea pig receptors in both in vitro and in vivo systems.     

A study of chlorophyll b in vivo

1. The absorption spectrum of chlorophyll b in vivo at 77°K is presented as the difference spectrum between preparations of spinach and chlorophyll b-free Vischeria stellata chloroplasts.

2. A shoulder on this spectrum around 662 nm is due to a component different from chlorophyll b. This component may well be identical with the chlorophyll a form, chlorophyll a (665).

3. The 77°K chlorophyll b absorption spectra in the nonfractionated photosyn-thetic pigment apparatus and in fractions mainly representing Photosystems 1 or 2 are not significantly different.

4. The aerobic irreversible photobleaching of chlorophyll b was studied in the intact pigment complex as well as in fractions mainly consisting of Photosystem 1 or 2. A two-step photobleaching was observed in all cases. The time-course of this bleaching was not significantly different for chlorophyll b in both fractions.

5. These results do not indicate that more than a single chlorophyll b complex occurs in vivo.     

Peripheral oxytocin treatment modulates central dopamine transmission in the mouse limbic structures

The effects of subcutaneous (s.c.) oxytocin treatment have been investigated on various parameters of dopaminergic neurotransmission in basal forebrain structures (nucleus olfactorius posterior + nucleus accumbens + septum) of the mouse. Acute oxytocin treatment failed to influence dopamine utilization in the basal forebrain. Following chronic injections of oxytocin (0.2 mg/kg) for 8 8 days, the neuropeptide decreased dopamine utilization. Neither in vivo nor in vitro oxytocin treatment was capable of influencing the in vitro uptake of [³H]dopamine in basal forebrain slices. The spontaneous release of [³H]dopamine (in the presence of 4.2 mM K⁺) from basal forebrain tissue slices was not affected by in vitro or acute or chronic in vivo oxytocin treatment. The stimulated release of [³H]dopamine (in the presence of 30 mM K⁺) was significantly inhibited by chronic in vivo oxytocin administration. Chronic oxytocin treatment decreased the B_max value of [³H]spiroperidol binding in the basal forebrain. The dissociation constant (K_d) of [³H]spiroperidol binding was not influenced by oxytocin. The data indicate that peripheral oxytocin treatment is capable of modifying dopaminergic neurotransmission in mouse basal forebrain regions.     

How to Characterize a Biological Antioxidant

An antioxidant is a substance that, when present at low concentrations compared to those of an oxidizable substrate, significantly delays or prevents oxidation of that substrate. Many substances have been suggested to act as antioxidants in vivo, but few have been proved to do so. The present review addresses the criteria necessary to evaluate a proposed antioxidant activity. Simple methods for assessing the possibility of physiologically-feasible scavenging of important biological oxidants (superoxide, hydrogen peroxide, hydroxyl radical, hypochlorous acid, haem-associated ferryl species, radicals derived from activated phagocytes, and peroxyl radicals, both lipid-soluble and water-soluble) are presented, and the appropriate control experiments are described. Methods that may be used to gain evidence that a compound actually does function as an antioxidant in vivo are discussed. A review of the pro-oxidant and anti-oxidant properties of ascorbic acid that have been reported in the literature leads to the conclusion that this compound acts as an antioxidant in vivo under most circumstances.     

In Vivo Esr Studies of Antioxidant Activity on Free Radical Reaction in Living Mice Under Oxidative Stress

In vivo antioxidant activity seems to be quite complicate due to multiple interaction with biomaterials and differs from results by in vitro experiments. In vivo estimation of antioxidant activity is performed by measuring TBA reactive substances in blood or hydrocarbon gases in breath, but these systems do not measure free radical reaction but the final products of oxidative reaction. In the present study, we applied in vivo ESR to evaluate antioxidant activity by monitoring the redox reaction of nitroxide radical and clearly found that the nitroxide is very susceptible to oxidative stress in vivo and quite useful to evaluate antioxidant activity non-invasively.     

The effect of in vivo heat treatments on blowfly flight muscle mitochondrial function: Effects on partial reactions of the respiratory chain

1. 1. The development of thermotolerance has been shown to protect blowfly flight muscle mitochondrial function from damage resulting from an LD₅₀ in vivo heat dose.

2. 2. The principal sites of the damage have been studied using specific inhibitors of the respiratory chain, rotenone and antimycin A, together with substrates that stimulate respiration through the different complexes.

3. 3. Complex I was identified as the primary site for heat damage. State III respiration was inhibited following the LD₅₀ in vivo heat dose, and uncoupling with FCCP did not restore respiration to control levels, indicating that the respiratory enzymes were inactivated. The development of thermotolerance protected this site from heat damage.

4. 4. In contrast, G3-P stimulated respiration was the same in control, LD₅₀ in vivo treated controls and LD₅₀, in vivo treated thermotolerant mitochondria, and significantly higher than state III respiration of LD₅₀ in vivo treated controls. This suggested that respiration through G3-P dehydrogenase, Co enzyme Q and Complex III is not damaged. However, as G3-P stimulated respiration of coupled mitochondria from LD₅₀ in-vivo treated flies was markedly reduced (El-Wadawi and Bowler, 1995. J. exp. Biol. 198: 2413–2421), phosphorylation at complex III may be inhibited also.

5. 5. Ferrocyanide stimulated respiration through cytochrome c-Complex IV was also inhibited in LD₅₀ in vivo treated flies, as compared with unheated control mitochondria. However, thermotolerance protected this site also from heat damage.

     

Evaluation of a three point pressure method for the determination of arterial transmission characteristics

The mathematical expressions required to analyse wave transmission characteristics (frequency dependent phase velocity, attenuation, and reflection) in arteries, under in vivo conditions, are summarized. In addition, a three point pressure method, which theoretically permits experimental determination of the propagation constant (phase velocity and attenuation), was tested under in vitro conditions. It is found to be a potentially powerful tool for in vivo studies if used with the appropriate constraints.     

DSIP affects adrenergic stimulation of rat pineal N-acetyltransferase in vivo and in vitro

The natural occurrence, sleep, and extra-sleep effects of delta sleep-inducing peptide (DSIP) have been shown by different laboratories. However, neither an in vitro assay system nor a probable mechanism of action of the peptide have been conclusively demonstrated so far. The recent finding that DSIP influences the nocturnal rise of N-acetyltransferase (NAT) activity in rat pineal led us to investigate a possible effect on pharmacologically induced NAT activity in vivo and in vitro. Stimulation of the enzyme with adrenergic drugs such as isoproterenol and phenylephrine was reduced by DSIP at doses of 150 and 300 μg/kg injected subcutaneously. In vitro, 6, 150 and 300 nM DSIP attenuated isoproterenol stimulation of the enzyme in cultured pineals, whereas 150 nM DSIP effectively reduced stimulation induced by a combination of the two drugs. The peptide alone did not influence NAT activity in vitro, but produced a slight stimulation in vivo. To our knowledge, these results represent the first report of a direct interaction of DSIP with adrenergic transmission. The in vitro system could prove useful for establishing possible mechanism(s) of action of the ‘sleep peptide.’     

可利霉素通过调控巨噬细胞极化影响黑色素瘤的增殖*

To investigate whether carrimycin (CAM) affects the occurrence and development of melanoma by regulating the polarization of macrophages, and the following related cell biology assays were used to examine its function. Methods: The effect of CAM on macrophage polarization was detected by real-time quantitative polymerase chain reaction (Q-RT-PCR) and Western blot. Flow cytometry and Cell Counting Kit-8 were used to detect the effect of CAM on mouse macrophages in vitro and in vivo phagocytosis and proliferation. Cell line-derived xenograft model was constructed via B16-F10 to evaluate the anti-tumor effect of CAM on melanoma. Results: In the mRNA level, CAM could up-regulate the levels of TNF-α and iNOS in M1 and down-regulate the level of Arg-1 in M2. In the protein level, CAM can increase the expression of p-STAT1 and decrease the expression of p-STAT3. In the cell line-derived xenograft model, these data shown that the occurrence and CAM development of melanoma was inhibited after CAM treatment, the tumor inhibition rate was 41.6%, and promoted the increase of the number of M1 macrophages (P<0.05). Conclusion: CAM promotes the increase in the number of M1 macrophages in vivo and inhibits the progression of melanoma, suggesting that CAM may achieve anti-tumor effects by inducing the polarization of macrophages to M1.     

Developmental profiles of glial enzymes in the chick embryo: In vivo and in culture

The activities of two glial cell enzymes, glutamine synthetase (a marker for astrocytes) and 2′,3′-cyclic nucleotide 3′-phosphohydrolase (a marker for oligodendrocytes and myelination) were studied in the developing chick embryo brain in vivo and in cultures derived from chick embryos. The in vivo findings showed that the activities of both enzymes parallel the patterns of gliogenesis and myelination. Glutamine synthetase follows similar patterns in culture and in vivo, whereas the developmental profile of 2′,3′-cyclic nucleotide 3′-phosphohydrolase appears to be affected by the culture conditions.     

A mechanism for heterogeneous endothelial responses to flow in vivo and in vitro

Exposure of endothelium to a nominally uniform flow field in vivo and in vitrofrequently results in a heterogeneous distribution of individual cell responses. Extremes in response levels are often noted in neighboring cells. Such variations are important for the spatial interpretation of vascular responses to flow and for an understanding of mechanotransduction mechanisms at the level of single cells. We propose that variations of local forces defined by the cell surface geometry contribute to these differences. Atomic force microscopy measurements of cell surface topography in living endothelium both in vitro and in situ combined with computational fluid dynamics demonstrated large cell-to-cell variations in the distribution of flow-generated shear stresses at the endothelial luminal surface. The distribution of forces throughout the surface of individual cells of the monolayer was also found to vary considerably and to be defined by the surface geometry. We conclude that the endothelial three-dimensional surface geometry defines the detailed distribution of shear stresses and gradients at the single cell level, and that there are large variations in force magnitude and distribution between neighboring cells. The measurements support a topographic basis for differential endothelial responses to flow observed in vivo and in vitro. Included in these studies are the first preliminary measurements of the living endothelial cell surface in an intact artery.