Comparative fluorescence spectroscopy of root caries lesions

In this study, the light-emission properties of carious and sound root surfaces were investigated under a wide range of excitation wavelengths. Human molar teeth with exposed root surfaces containing light- and dark-discolored root caries (n = 3 of each) were selected. Emission spectra were recorded from carious and corresponding sound root surface areas from each tooth by using a fluorescence spectrophotometer at excitation wavelengths from 360 nm up to 580 nm, in steps of 20 nm. The spectra were corrected for fluctuations in detector sensitivity and excitation light intensity, and normalized to peak intensity. Excitation spectra were recorded for selected emission wavelengths that showed maximum intensity. Light- and dark-discolored root surface caries showed distinct fluorescence emission bands between 600 and 700 nm that were not present in sound root surface areas. These bands were strongest for excitation wavelengths between 390 and 420 nm. The excitation spectra of root caries revealed maximum excitation at around 405 nm, which is equivalent to the Soret band of porphyrin compounds. The emission spectra of both types of root caries lesions were shifted towards longer wavelengths (red shift at half maximum) when compared to the spectra of corresponding sound root surfaces. The red shift for dark-discolored root caries was higher than for light-discolored lesions at all excitation wavelengths.     

A synthetic porphyrin as an effective dual antidote against carbon monoxide and cyanide poisoning

Simultaneous poisoning by carbon monoxide (CO) and hydrogen cyanide is the major cause of mortality in fire gas accidents. Here, we report on the invention of an injectable antidote against CO and cyanide (CN^–) mixed poisoning. The solution contains four compounds: iron(III)porphyrin (Fe^IIITPPS, F), two methyl-β-cyclodextrin (CD) dimers linked by pyridine (Py3CD, P) and imidazole (Im3CD, I), and a reducing agent (Na₂S₂O₄, S). When these compounds are dissolved in saline, the solution contains two synthetic heme models including a complex of F with P (hemoCD-P) and another one of F with I (hemoCD-I), both in their iron(II) state. hemoCD-P is stable in its iron(II) state and captures CO more strongly than native hemoproteins, while hemoCD-I is readily autoxidized to its iron(III) state to scavenge CN^– once injected into blood circulation. The mixed solution (hemoCD-Twins) exhibited remarkable protective effects against acute CO and CN^– mixed poisoning in mice (~85% survival vs. 0% controls). In a model using rats, exposure to CO and CN^– resulted in a significant decrease in heart rate and blood pressure, which were restored by hemoCD-Twins in association with decreased CO and CN^– levels in blood. Pharmacokinetic data revealed a fast urinary excretion of hemoCD-Twins with an elimination half-life of 47 min. Finally, to simulate a fire accident and translate our findings to a real-life scenario, we confirmed that combustion gas from acrylic cloth caused severe toxicity to mice and that injection of hemoCD-Twins significantly improved the survival rate, leading to a rapid recovery from the physical incapacitation.

Fire accidents frequently occur around the world and the consequent inhalation of combustion gases represents the leading cause of death under these circumstances (1–10). Typically, combustion gases consist, among others, of carbon dioxide, water (H₂O), carbon monoxide (CO), hydrogen cyanide (HCN), hydrochloric acid, nitrogen oxide, and sulfur oxide. Their amounts depend on the materials of combustion (3–10) and, among them, CO and HCN are the most dangerous due to their severe toxic effects in humans (3–4, 5–15). CO is generated during incomplete combustion of carbon materials while HCN derives from carbon- and nitrogen-containing materials. Thus, CO and HCN gases are simultaneously released when synthetic materials such as plastics, acrylic cloths, and urethanes are burned in buildings. Once inhaled, CO strongly binds to ferrous iron(II) heme proteins such as hemoglobin (Hb) in erythrocytes and myoglobin in muscles (16–19), thus compromising oxygen (O₂) transport/storage in the blood circulation and tissues. On the contrary, HCN binds as cyanide ion (CN^–) to ferric iron(III) heme, preferentially targeting cytochrome c oxidase (CcO) in mitochondria and interrupting O₂-dependent energy production (11, 20–22). Likewise, the toxic effects of CO on mitochondrial respiration are ascribed to its ability to bind to cytochrome c oxidase (23–25). Therefore, both CO and HCN can inhibit aerobic respiration mediated by several heme proteins leading to anoxia-induced lethal toxicity. As the molecular mechanisms of CO and HCN toxicity are closely related, additional or synergistic deleterious effects can be expected when these two gases are produced and inhaled at the same time (26–31). Therapeutic strategies to treat either CO or HCN poisoning have been developed independently (11, 13, 22, 32–37). However, to our knowledge, there is no medical intervention at present to neutralize simultaneously CO and HCN with an effective treatment in vivo.In the present study, we have developed an injectable antidote for CO and HCN mixed poisoning. This agent contains supramolecular compounds, termed hemoCDs, composed of a water-soluble iron(II/III)porphyrin and two cyclodextrin (CD) dimers. Based on our previous research on the synthesis and characterization of heme protein model structures (38–40), the gas-binding ability and the redox status of the iron center of the porphyrin can be regulated by the linker structure of the CD dimers englobing the porphyrin. The porphyrin complexed with a CD dimer having a pyridine linker (hemoCD-P, Fig. 1 A, Left) is stable in the iron(II) state in vivo and shows much higher CO-binding affinity compared to the affinities reported for native heme proteins (41–45). On the contrary, the porphyrin complexed with a CD dimer having an imidazole linker (hemoCD-I, Fig. 1 A, Right) is stable in the iron(III) state and shows a higher binding affinity to CN^– than native ferric met-hemoglobin (met-Hb) (46, 47). These two complexes do not bind to plasma proteins in the circulation when injected separately and are quickly excreted in urines without any chemical decomposition. Therefore, these compounds have the ability to capture either CO or CN^– to their iron(II/III) centers in vivo and expel these toxic ligands from the organism (41–47). Here, we have developed hemoCD-Twins that contains both hemoCD-P and hemoCD-I in saline for simultaneous removal of CO and HCN in vivo. This paper describes the primary pharmacological properties of hemoCD-Twins and its detoxification effects in animals intoxicated with CO and CN^–. To simulate a real-life fire accident, the burning of acrylic cloth with consequent release of combustion gases was also used as an experimental approach for antidotal tests. We found that hemoCD-Twins exhibits the following features: 1) The synthetic compounds are storable at room temperature over a year thanks to their chemical stability; 2) the solution can be quickly prepared without the need of special handlings; 3) a single administration of hemoCD-Twins shows immediate dual antidotal effect against CO and CN^–; and 4) the injected solution is quickly eliminated from the body without significant side effects. We are envisioning a scenario whereby a person who is accidentally exposed to fire gases containing CO and HCN can be promptly treated at the site by infusion with hemoCD-Twins.Open in a separate windowFig. 1.hemoCD-Twins as an antidote system against CO and CN^– mixed poisoning. (A) Biomimetic heme protein model compounds hemoCD-P and hemoCD-I that are used as CO and CN^– scavengers in vivo. (B) Chemical structures of the four components P, I, F, and S contained in hemoCD-Twins. (C) Preparation of hemoCD-Twins. Three powder compounds, F, P, and I, were dissolved in PBS in a 2:1:1 molar ratio, where the solution contains hemoCD-P and hemoCD-I in ferric iron(III) states. The solution is stable and storable at room temperature. The reducing agent S is added just before use. (D) Schematic illustration for the simultaneous removal of CO and CN^– by a single injection of hemoCD-Twins in vivo. CO and CN^– are removed from living organisms and excreted in the urine with hemoCD-P and hemoCD-I in ferrous iron(II) and ferric iron(III) complexes, respectively.     

竹笋提取液复合制剂在失血性贫血中的疗效观察

目的观察竹笋提取液复合制剂治疗失血性贫血的疗效。方法分别采用医用生化分析仪、HP1100色谱仪以及ICTMS检测竹笋提取液中葡萄糖、总蛋白、宏量元素,氨基酸和微量元素的含量。以小鼠内眦静脉丛取血法,建立失血性贫血小鼠动物模型;采用灌胃给药的方式,2个实验组(药物组)分别给予竹笋提取液复合铁制剂1(0.15%铁卟啉、10%蜂蜜)、制剂2(70%竹笋提取液、0.15%铁卟啉、10%蜂蜜),1个对照组给予同等剂量去离子水,于给药的不同时间点0、18、42、67和90 h从小鼠尾静脉取血,测定血红蛋白(Hb)、红细胞(RBC)、红细胞压积(Hct)。急性毒性试验采用小鼠最大灌胃量给药,观察有无毒性反应。结果制剂2中的竹笋提取液中含有葡萄糖,蛋白质,Na、Cl、Mg、K、Ca、P等多种宏量元素,刺激或参与造血功能的Mn、Fe、Zn、Cu等微量元素,以及促进非血红素铁吸收的多种氨基酸成分;小鼠失血后立刻给药,制剂1与制剂2对失血性贫血的疗效均好于对照组,且制剂2优于制剂1(P<0.05);急性经口毒性动物实验未见异常。结论竹笋提取液含有丰富的葡萄糖、蛋白质以及多种元素,能够刺激造血,扩充血容量,其复合铁制剂对失血性贫血的恢复有促进作用。     

Myeloid-derived suppressor cells are increased in frequency but not maximally suppressive in peripheral blood of Type 1 Diabetes Mellitus patients

Type 1 Diabetes Mellitus (T1D) results from the destruction of insulin-producing beta cells in the pancreas by autoreactive T cells. Myeloid derived suppressor cells (MDSCs) are a recently identified immune cell subset that down-regulate T cells. Whether defects in MDSC numbers or function may contribute to T1D pathogenesis is not known. We report here that MDSCs are unexpectedly enriched in peripheral blood of both mice and patients with autoimmune diabetes. Peripheral blood MDSCs from T1D patients suppressed T cell proliferation in a contact-dependent manner; however, suppressive function could be enhanced with in vitro cytokine induction. These findings suggest that native T1D MDSCs are not maximally suppressive and that strategies to promote MDSC suppressive function may be effective in preventing or treating T1D.     

Arsenic and porphyrins

BACKGROUND: To evaluate the possible effect of inorganic arsenic (iAs) and of its species on the urinary excretion of porphyrin homologues. METHODS: Total porphyrins and their homologues (copro, penta, hexa, hepta, uroporphyrins) and arsenic species (trivalent and pentavalent As; monomethyl arsonic acid; dimethyl arsenic acid; arsenobetaine) were measured respectively by HPLC and HPLC-ICP MS in urine from 86 art glass workers exposed to iAs and from 54 controls. RESULTS: A significant increase in the excretion of penta and uroporphyrins was demonstrated for workers exposed to As; As3 was the species best correlated with urinary porphyrin excretion. CONCLUSIONS: The increase of urinary excretion for some porphyrin homologues appears to be consistent with the inhibition by As of URO-decarboxylase in the heme biosynthesis pathway. The determination of urinary porphyrin homologues could be useful to assess, on a group basis, some early effects of arsenic and to demonstrate possible individual susceptibility to the element.     

Photodynamic inactivation of fibroblasts by a cationic porphyrin

An important determinant of the clinical applicability and value of antimicrobial photodynamic inactivation (PDI) is the cytotoxicity of the treatment to human cells. We evaluated the in vitro cytotoxicity of PDI to human dermal fibroblasts using 5-phenyl-10,15,20-tris(N-methyl-4-pyridyl)porphyrin chloride (TriP[4]) as the photosensitiser. The fibroblasts were exposed to a PDI regime that is known to be sufficient for the inactivation of Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans [1]. The PDI experiments were carried out in phosphate-buffered saline (PBS) and in 6.25%, 12.5%, 25% and 50% fetal calf serum (FCS)/PBS suspensions. Cell viability subsequent to exposure was evaluated after 0 h, 6 h and 18 h using the methylthiazoletetrazolium (MTT) assay and compared to pretreatment values. At a TriP[4] concentration previously demonstrated to induce a 5log₁₀-unit reduction in a viable count for S. aureus, 79% of the fibroblasts were photo-inactivated. Increasing the FCS concentration in the medium protected the fibroblasts against PDI. Based on our in vitro results, we propose that in vivo PDI of S. aureus holds potential; however, PDI of P. aeruginosa and C. albicans will probably require such a strong PDI regime that it will induce substantial damage to fibroblasts.     

Induction of the mitochondrial permeability transition by selenium compounds mediated by oxidation of the protein thiol groups and generation of the superoxide

The cancer chemopreventive effect of selenium compounds cannot be fully explained by the role of selenium as a component of antioxidant enzymes, suggesting that other mechanisms, such as thiol oxidation or free radical generation, also underlie this effect. The toxicities of six different selenium compounds (selenite, selenate, selenocystine, selenocystamine, selenodioxide, and selenomethionine) have now been compared in HepG2 human hepatoma cells and isolated rat liver mitochondria. Selenite, selenocystine, and selenodioxide induced apoptosis in HepG2 cells and mediated oxidation of protein thiol groups in both HepG2 cells and isolated mitochondria. Selenocystamine oxidized protein thiol groups in isolated mitochondria and crude extracts of HepG2 cells but not in intact HepG2 cells, suggesting that this compound is not able to cross the cell membrane. The selenium compounds capable of oxidizing thiol groups also induced the mitochondrial permeability transition (MPT) in isolated mitochondria. Furthermore, they generated the superoxide (O(2) .-) on reaction with glutathione in the presence of mitochondria, and an O(2) .-) scavenger inhibited their induction of the MPT. These results suggest that the pro-apoptotic action of selenium compounds is mediated by both thiol oxidation and the generation of O(2) .-), both of which contribute to opening of the MPT pore.     

Detection and quantification of breast tumor necrosis with MR imaging: value of the necrosis-avid contrast agent Gadophrin-3

RATIONALE AND OBJECTIVES: The authors evaluated the use of T1-weighted magnetic resonance (MR) imaging with Gadophrin-3 enhancement and of plain T2-weighted MR imaging to detect and quantify breast tumor necrosis. MATERIALS AND METHODS: Twenty EMT-6 tumors (mouse mammary sarcoma), implanted into the mammary fat pad of BALB/c-AnNCrl mice, underwent MR imaging with plain T2-weighted and T1-weighted fast field echo sequences before and 24 hours after injection of Gadophrin-3, a new necrosis-avid contrast agent. Tumor necrosis on MR images was quantified by means of a dedicated segmentation program and was correlated with histologic findings. RESULTS: In all tumors a central necrosis was revealed by histopathologic analysis, and central enhancement was seen with Gadophrin-3 on T1-weighted images. Small tumors (diameter, < 1 cm) showed an inhomogeneous central enhancement, whereas larger tumors (diameter, > 1 cm) enhanced mainly in the periphery of necrotic tissue. Plain T2-weighted images showed a hyperintense central area in only three of 20 cases with a large central necrosis. CONCLUSION: Gadophrin-3-enhanced T1-weighted images are superior to plain T2-weighted images for the detection of necrosis in a murine tumor xenograft model.     

Urinary porphyrins in patients with endemic chronic arsenic poisoning caused by burning coal in China

Objective  To evaluate the effect of arsenic (As) on the porphyrin biosynthetic pathway, urine samples from patients with endemic chronic arsenic poisoning were examined. Subjects and Methods  The subjects were 16 patients, who had been exposed to As from burning coal for 8 to 25 years, and 16 controls living in the same region in Guizhou Province in southwest China. Concentrations of urinary As, porphyrins and ALA were determined by induced coupled plasma mass spectrometry (ICP-MS), high performance liquid chromatography (HPLC) with a reversed-phase column and fluorescence detector, and colorimetric spectrophotometry, respectively. Results  Concentrations of As in patients and controls, 184.40±200.04 and 86.82±64.20μ g/g creatinine (mean ±SD) respectively, were significantly different (p<0.05). The concentrations of various kinds of urinary porphyrins, including isomers I and III of coproporphyrin and pentacarboxylporphyrin, were determined. Positive correlations were observed between As and porphyrins (e.g. total porphyrins, hexacarboxylporphyrin and coproporphyrin III) or between As and ALA in male and female patients. However, porphyrin and ALA concentrations were not significantly different between the patients and the controls. Urinary porphyrin concentrations in females were higher than those in males. Conclusion  Exposure to As from burning coal may influence porphyrin biosynthesis.     

新型尾式卟啉的制备、表征及其与DNA相互作用的初步研究

目的合成1个新型尾式卟啉化合物（目标化合物1）,并对其与小牛胸腺DNA（CT-DNA）的相互作用方式进行初步研究。方法以吡咯、对羟基苯甲醛和苯甲醛为原料,制备得到以柔性碳链连接的目标化合物1,采用MS1、HNMR以及UV-vis等对化合物进行表征;并采用紫外光谱、荧光光谱以及黏度实验初步研究目标化合物1与CT-DNA的相互作用。结果目标化合物1的电喷雾质谱（ESI-MS）在997.4出现一个归属于[M＋H]＋的分子离子峰,实验结果与理论计算一致;目标化合物1的电子吸收光谱分别在419 nm出现一个归属于卟啉环的特征Soret吸收,在500~700 nm之间出现归属于卟啉环的特征Q-带吸收。结论目标化合物1能够以插入方式与DNA分子发生结合。