In viva PHOTODYNAMIC EFFECTS OF PHTHALOCYANINES IN A SKIN-FOLD OBSERVATION CHAMBER MODEL: ROLE OF CENTRAL METAL ION AND DEGREE OF SULFONATION

Six sulfonated metallophthalocyanines, chelated with either aluminum or zinc and sulfonated to different degrees, were studied in vivo for their photodynamic activity in a rat skin-fold chamber model. The chamber, located on the back of female WAG/Rij rats, contained a syngeneic mammary carcinoma implanted into a layer of subcutaneous tissue. Twenty-four hours after intravenous administration of 2.5 μmol/kg of one of the dyes, the chambers received a treatment light dose of 600 J/cm² with monochromatic light of 675 nm at a power density of 100 mW/ cm². During light delivery and up to a period of 7 days after treatment, vascular effects of tumor and normal tissue were scored. Tumor cell viability was determined by histology and by reimplantation of the chamber contents into the skin of the same animal, either 2 h after treatment or after the 7 day observation period. Vascular effects of both tumor and subcutaneous tissue were strongest with dyes with the lowest degree of sulfonation and decreased with increasing degree of sulfonation. Tumor regrowth did not occur with aluminum phthalocyanine mono- and disulfonate and with zinc phthalocyanine monosulfonate. With the protocol that was used, complete necrosis without recovery was only observed when reimplantation took place at the end of the 7 day follow-up period. Reimplantation 2 h after treatment always resulted in tumor regrowth. At this interval, the presence of viable tumor cells was confirmed histologically. In general tumor tissue vasculature was more susceptible to photodynamic damage than vasculature of the normal tissue. The effect on the circulation of both tumor and normal tissue increased with decreasing degree of sulfonation. Based on this study, the photodynamic effects using the six sulfonated metallophthalocyanines on the vasculature can be ranked from high to low as: AlPcS₂= ZnPcS₁ > AIPcS₁ > AIPcS₄ > ZnPcS₂ > ZnPcS₄.     

牛血清白蛋白在NVP/HEMA无规共聚物水凝胶上的吸附研究

合成了不同含水量的N-乙烯吡咯烷酮(NVP)／甲基丙烯酸-β-羟乙酯(HEMA)共聚物水凝胶．研究了温度、pH值，蛋白质初浓度及离子强度等因素对牛血清白蛋白吸附性能的影响．采用紫外分光光度法测定BSA的吸附量．结果表明，蛋白质初浓度越高．温度越高，离子强度越大；蛋白质内部更多的疏水性氧基酸残基暴露于外部．吸附量增加：在等电点pH=4．7附近蛋白质沉积量最大．     

Chip-based capillary electrophoresis with an electrodeless nanospray interface

A sheathless and electrodeless nanospray interface has been used to interface a polycarbonate capillary electrophoresis (CE) chip to a mass spectrometer (MS). The chip was made of two flat polycarbonate plates which were bolted together. Channels were imprinted in one of the plates with metal wires, using a hydraulic press. A short tapered capillary connected to the chip was used as the nanospray emitter. The advantage of this electrodeless interface is that it was not necessary to apply a electrospray voltage to the chip or the nanospray emitter. Instead, the CE voltage already applied to the buffer compartment on the chip, to drive the electrophoresis, was used to generate the spray also. A low conductivity buffer of 1.25 mmol/L ammonium acetate in 80% methanol was used to obtain a large electric field across the buffer channel. The performance of the device was evaluated by analyzing a mixture of three beta-agonists Relative standard deviation (RSD) values obtained were between 4.8 and 5.0%. A sample concentration of 40 nmol/L resulted in a signal-to-noise ratio of 2 to 5 for the different components. Compared to a conventional CE analysis in a fused silica capillary with UV detection, only a minor loss of resolution was observed, which can be attributed to the design of the chip.     

Time-dependent pump-probe spectra of NeBr2

Time- and frequency-resolved pump-probe measurements on NeBr2 have been performed to better characterize its fragmentation dynamics on the B electronic state for vibrational levels in the energy region of the transition from direct vibrational predissociation to intramolecular vibrational relaxation dynamics. Above nu'=20 of the Br2 stretching mode, it was observed that the dependence of lifetime on the vibrational quantum number deviates from the energy-gap law by leveling off in the range of 10 psE transitions of the complex. These transitions are shifted 20 cm(-1) to lower energy from the free Br2 resonances, indicating an E state Ne-Br2 bond energy of 82 cm(-1). Measurements of NeBr2 vibrational predissociation via the delta nu=-2 channel were also performed for nu'=27, 28, and 29. The closing of the delta nu=-1 channel leads to an increase in the lifetimes of these vibrational levels. A new Nd:yttrium aluminum garnet pumped dual optical parametric oscillator/optical parametric amplifier system is described that allows us to conveniently record time-delayed pump-probe spectra with 2-cm(-1) spectral resolution and 15-ps time resolution.     

Capillary isoelectric focusing-mass spectrometry for shotgun approach in proteomics

We report on capillary isoelectric focusing-mass spectrometry (CIEF-MS) of complex peptide mixtures in the absence of carrier ampholytes. Furthermore, the use of low concentrations of carrier ampholytes as mere spacers is investigated. Carrier ampholytes are complex mixtures of amphoteric compounds with high buffering capacity. Since all peptides are amphoteric compounds by themselves, the use of carrier ampholytes may be superfluous to establish a stable pH gradient in CIEF analysis of protein digests. Our research showed that when carrier ampholytes are omitted, the analyte ions are not focused at their isoelectric point. The analytes are charged, leading to electrophoretic mobility uncharacteristic for CIEF. The method was tested for a five-protein-mixture at 0.02 mg/mL per protein and 0.05 mg/mL per protein. At the lower concentration, the analytes were stacked during the focusing process in only a limited length of the capillary. Therefore, the higher concentration led to better separation efficiency. It was found that at low concentration (0.20%) the carrier ampholytes could work as spacers. Though it led to sensitivity losses of 15-45%, this was compensated by the higher separation efficiencies seen. The method was evaluated with an eight-protein-mixture, of which all could be identified after performing MS/MS.     

膦取代的羰基铂簇的合成,结构和性质

Pt(PPh_3)_2Cl_2在碱性介质中,与一氧化碳直接进行还原及羰基化反应,得到五种膦取代的羰基铂配合物:Pt_5(μ_2-CO)_5(CO)(PPh_3)_4 1,Pt_3(μ_2-CO)_3(PPh_3)_3 2,Pt_3(μ_2-CO)_3(PPh_3)_4 3,Pt_4(μ_2-CO)_5(PPh_3)_4 4,以及Pt(Cl)(PPh_3)_2(COOCH_3) 5。经X-射线单晶衍射分析,确定了新的三核铂羰基簇2以及配合物5的分子结构。还讨论了1和5的生成机理。     

Effects of partial/asymmetrical filling of micelles and chiral selectors on capillary electrophoresis enantiomeric separation: generation of a gradient

The effect of several experimental parameters on enantiomeric separations in micellar capillary electrophoresis (MCE) was studied. A model separation system was tested. It was composed of an acidic phosphate buffer with sodium dodecyl sulfate (SDS) and hydroxypropyl-beta-cyclodextrin (HP-beta-CD) as the chiral selector. A substituted angelicin was used as a chiral analyte. Changes in the concentration of SDS micelles/SDS monomers in the presence of HP-beta-CD and their impact on the enantioselective separation were investigated. Variation of the composition of electrolytes in the individual compartments of the separation system (inlet vial, capillary, and outlet vial) affected both the migration times and the resolution of the enantiomers. Current vs. time dependencies also were monitored during the separations. A mathematical model of electromigration in micellar systems with chiral selector present was proposed and a computer simulation was used to explain the observed phenomena and to confirm the generation of a CD/SDS-micelle concentration gradient under certain experimental conditions. This is the reported first attempt of a computer simulation of the complex, dynamic chiral environment of the CD-SDS-MCE system.     

2,6-dicyano-1,5-dimethylsemibullvalene as a probe for homoaromatic molecules of the Dewar-Hoffman type

The 2,6-dicyano-1,5-dimethylsemibullvalene (2d) synthesized via the bicyclo[3.3.0]octanedione 7 exists as a classical ground state which is lower in energy by less than 5 kcal/mole than the homoaromatic transition of the Cope rearrangement of 2d.     

Experimental analysis and modified rotor description of the infrared fundamental band of HCl in Ar, Kr, and Xe solutions

We report an experimental study of the rotovibrational fundamental PQR-band shapes in the IR absorption spectra of HCl dissolved in condensed rare gases in a wide range of temperatures. The effective vibrational frequencies are determined from analysis of the fine rotational structure partially resolved in the band wings. The central Q-branch components appear redshifted with respect to the effective vibrational frequencies, their shifts in different solvents found to match the HCl stretching mode shifts in binary Rg...HCl van der Waals heterodimers. Theoretical quasi-free rotor and modified rotor models are applied to describe evolution of the band profiles at changing thermodynamic conditions. Both models are shown to reproduce equally well the observed spectral density distributions in the band wings. However, the modified rotor formalism that accounts for depopulation of the lower-energy rotational solute states provides better agreement with the experiment in the range of the P- and R-branch maxima. We surmise that the Q branches separated from the measured spectral profiles are formed by transitions between rotationally hindered states of diatomic molecules coupled to the solvent by the local anisotropy of the interaction potential.     

Physicochemical aspects of microbial adhesion — Influence of antibody adsorption on the deposition ofStreptococcus sobrinus in a parallel-plate flow chamber

Deposition of the oral bacteriumStreptococcus sobrinus HG977 onto glass (water contact angle 0°) and onto FEP-Teflon (fluoroethylenepropylene; water contact angle 110°) was studied in a parallel-plate flow chamber in the presence and absence of polyclonal antibodies (pAb) and monoclonal antibodies (mAbs) adsorbed onto the cells. The zeta potentials of the bacteria ranged from −7.1 to −8.5 mV at pH 6.8 and were not affected by the presence of pAb or mAbs. Hydrophobicity (by water contact angles) increased from 30° (no antibodies) to 88° in the presence of pAb adsorbed onto the bacterial cell surface. The untreatedS. sobrinus had a greater tendency to adhere to glass (44.5 × 10⁶ cm⁻²) than to FEP-Teflon (18.3 × 10⁶ cm⁻²), in accordance with thermodynamic modelling. After preincubation ofS. sobrinus with pAb, its clear preference for adhesion to glass disappeared as expected from its increased hydrophobicity. Although forS. sobrinus preincubated with OMVU10 no difference was found in hydrophobicity in comparison to the untreated bacteria, the number of bacteria adhering to glass decreased to 10.2 ¢ 10⁶ cm⁻². Formation of bacterial aggregates was found whenS. sobrinus, preincubated with pAb or OMVU10, adhered to glass and FEP. This was also observed when untreated bacteria adhered to glass coated with OMVU10, or to FEP coaled with OMVU10 or pAb. Adhesion in these experiments is therefore thought to occur via near-neighbour collection induced by the presence of pAb or mAbs. Low numbers of bacteria were removed from glass after draining the flow cell, whereas high numbers of untreated bacteria and bacteria preincubated with OMVU10 were removed from FEP.S. sobrinus cells preincubated with pAb were not removed but piled up. It was concluded that the adhesion of untreatedS. sobrinus andS. sobrinus preincubated with pAb is in accordance with thermodynamic modelling, based on the overall wettability of the cell surfaces, whereas the adhesion ofS. sobrinus preincubated with OMVU10 may be through localized interactions, not expressed in overall surface properties.