BIOLOGICAL ACTIVITIES OF PHTHALOCYANINES—VIII. CELLULAR DISTRIBUTION INV–79 CHINESE HAMSTER CELLS AND PHOTOTOXICITY OF SELECTIVELY SULFONATED ALUMINUM PHTHALOCYANINES

Abstract— Water soluble chloro aluminum phthalocyanines sulfonated to different degrees are studied for phototoxicity and cellular distribution inV–79 Chinese hamster cells. The more hydrophobic disulfonated dyes, with sulfonate substituents on adjacent benzyl groups of the phthalocyanine ring structure, exhibited the best cell penetrating properties and the highest phototoxicity. Fluorescence microscopy revealed that the dye was uniformly distributed in the cytoplasm but absent in the nucleus. The greater cell membrane penetrating properties of the lower as compared to the higher sulfonated dyes are attributed to the amphiphilic nature of the former.     

In vitro PHOTODEGRADATION OF CHLORPROMAZINE

The in vitro photodecomposition of chlorpromazine (CPZ) was investigated with the aim to evaluate possible reactive determinants that could play a role in the occurrence of the in vivo -observed photosensitivity. In view of the in vivo situation, CPZ was dissolved in low concentration in buffered aqueous solution (pH 7.4) or in dilute human serum and irradiated with low intensity (5–7 W m^-2) UV-A and UV-B. No distinct difference was found between UV-A or UV-B irradiation as far as photoproduct formation is concerned. This suggests the same degradation mechanism at both wavelength ranges. In buffered aqueous solution, irradiation of CPZ resulted in 65 and 90% 2-hydroxypromazine (PZOH), 5 and 7% promazine (PZH) and 2 and 0% chlorpromazinesulfoxide (CPZSO) under aerobic and anaerobic conditions, respectively. In dilute human serum, there was only a shift in the PZH/PZOH ratio, probably as a result of H-atom or electron donation by sulfur containing groups present in proteins. The results demonstrate that photodegradation of CPZ in vitro , under conditions relevant to the in vivo situation, proceeds almost entirely by dechlorination rather than by radical cation formation (the essential pathway of CPZSO production). Thus we conclude that the thiyl radical cation probably does not play a major role in the in vivo -observed phototoxic reactions.     

INTRAUTERINE 5-AMINOLEVULINIC ACID INDUCES SELECTIVE FLUORESCENCE AND PHOTODYNAMIC ABLATION OF THE RAT ENDOMETRIUM*

Abstract— 5-Aminolevulinic acid (ALA), a precursor of protoporphyrin IX (Pp IX), was administered into the rat uterine cavity in an attempt to selectively ablate the endometrium. Doses of ALA ranging from 4 to 50 mg were injected into one uterine horn of rats while the vehicle (saline) was injected into the contralateral horn. Animals were divided into three groups. In group one, the uterine horns were removed and processed for either fluorescent mi- croscopy or spectrophotofluorometry 3 h later. In group two, rats were allowed to survive for either 2 or 10 days, and then the uterine horns were harvested and processed histologically. In group three, both uterine horns were exposed to transmural light (approximately 150 J/cm*) 3 h after administration of ALA or saline and processed histologically either 2 or 10 days later. Fluorescent microscopy showed fluorescence in the endometrium and not in the myometrium. The maximum emission spectra of endometrial fluorescence occurred at 630 and 690 nm, characteristic of Pp IX. In contrast, no fluorescence was detected in saline-treated uterine horns. Light exposure resulted in extensive damage only to the ALA-treated endometrium. There was no indication of regeneration 10 days after treatment. We conclude from these studies that ALA administered into the lumen of the rat uterus is selectively converted into Pp IX within the endometrium. Furthermore, photoactivation of the Pp IX results in selective ablation of the endometrium.     

COLLECTIVE DECISION MAKING IN AN INTERNATIONAL RIVER POLLUTION MODEL

In this paper, we study international river pollution problems. We introduce a model in which countries located along a river from upstream to downstream derive benefits from causing pollution, but also incur environmental costs from experiencing its own pollution and the pollution of all its upstream countries. The total welfare, being the sum of all benefits minus the sum of all costs, is maximized when all countries cooperate. Several principles from international water law are applied to find reasonable and fair distributions of the total welfare that can be obtained under full cooperation. Such a distribution of the welfare at efficient pollution levels can be implemented by monetary compensations.     

Contour Dynamics with Non-uniform Background Vorticity

In this paper it is demonstrated how a contour dynamics method can be used to simulate the behaviour of vortices in the presence of non-uniform background vorticity in general, and on the γ-plane in particular. For standard contour dynamics in case of zero, or uniform background vorticity, the initial continuous vorticity distributions of the vortices are replaced by appropriate piecewise-uniform distributions. Then, the evolution of the contours separating the several regions of uniform vorticity, are followed in time. In the case of non-uniform background vorticity, it is necessary to replace the sum of the (relative) vorticity of the vortices and the background vorticity by a piecewise-uniform distribution. This has several consequences for applying the method of contour dynamics, which are discussed in this paper. The resulting method is tested on some numerical examples. One of them is (qualitatively) compared with laboratory experiments carried out in a rotating tank.     

DELPHI有机共轭体系MM力场的优化和应用

运用我们建议的SC-HMO方法优化了有机共轭烯烃的DELPHIMM力场。将优化所得力场和参数用于计算各类型101个共轭化合物的分子几何构型、生成热、偶极矩和IR频率等, 结果可与MM3法相比。     

On Some Families of Smooth Affine Spherical Varieties of Full Rank

Let G be a complex connected reductive group. Losev has shown that a smooth affine spherical G-variety X is uniquely determined by its weight monoid, which is the set of irreducible representations of G that occur in the coordinate ring of X. In this paper we use a combinatorial characterization of the weight monoids of smooth affine spherical varieties to classify:(a) all such varieties for G = SL(2) × C~×and(b) all such varieties for G simple which have a G-saturated weight monoid of full rank. We also use the characterization and Knop's classification theorem for multiplicity free Hamiltonian manifolds to give a new proof of Woodward's result that every reflective Delzant polytope is the moment polytope of such a manifold.     

The lowest triplet state of luminescent scheelites: a study of the MoO24- ion by electron paramagnetic resonance with optical detection

The fine-structure and g tensors of the luminescent triplet state of the molybdate anion in single-crystals of CaWO₄:MoO₄, CdMoO₄ and PbMoO₄, all with the scheelite structure, are reported. In all three hosts the MoO24- ion is distorted on excitation. The directions of the principal axes of the fine-structure and g tensors support the idea that the effect results from the combined action of a Jahn-Teller instability and the crystal field. The hyperfine coupling of the ⁹⁵Mo and ⁹⁷Mo nuclei points towards excitation to an orbital with a large contribution of Mo 4d_3z2-2r.     

Microwave rotational spectra of the Kr-NH3 van der Waals complex

Rotational spectra of the Kr-NH₃ van der Waals complex were measured in the frequency range between 4 and 24 GHz using a pulsed jet cavity Fourier transform microwave spectrometer. The isotopomers studied included those of NH₃, ¹⁵NH₃, ND₃, NHD₂, and NH₂D with the five most abundant isotopes of Kr. Tunnelling splittings due to the inversion of the ammonia subunit within the ground state of the complex were observed for all three deuterium containing isotopomers. In the NH₃ and ¹⁵NH₃ isotopomers, one of the tunnelling states has a spin statistical weight of zero and the splitting can therefore not be measured in these species. Nuclear quadrupole hyperfine structure arising from the ¹⁴N and ⁸³Kr nuclei was measured and the corresponding nuclear quadrupole coupling constants were determined. These were used to estimate structural parameters and derive information about the intermolecular dynamics. Smaller nuclear quadrupole splittings arising from the deuterium nuclei were observed but could not be resolved. The ground state spectroscopic constants were compared with experimental and theoretical data previously reported for Ar-NH₃ and its isotopomers. For the Kr-ND₃ isotopomers, additional transitions were observed and assigned to the two inversion components of an excited internal rotor state. A fit of the spectroscopic constants revealed the presence of a Coriolis perturbation, similar to that reported for this state in Ar-ND₃ and Ar-NH₃.     

The magnetic field dependence of the electron spin polarization in consecutive spin correlated radical pairs in type I photosynthetic reaction centres

The magnetic field/microwave frequency dependence of the spin polarized EPR spectra of the sequential spin correlated radical pairs P⁺A^? ₁ and P⁺F^? _x in type I photosynthetic reaction centres is investigated. Experimental data are presented for photosystem (PS) I and reaction centres of heliobacteria at × band (9.7 GHz) and K band (24 GHz). In photosystem I at ambient temperatures the lifetime of A ^? ₁ is ~290 ns and both states are observable by transient EPR. In heliobacteria, electron transfer to F_x occurs within ~600 ps and only the state P⁺F^? _x is observed. The experimental data show a net polarization of P⁺ in the state P⁺F^? _x, which displays a clear dependence on the strength of the external field. The net polarization generated in sequential radical pairs is expected to pass through a maximum as a function of the Zeeman energy when the characteristic time of singlet-triplet mixing is comparable with the lifetime of the precursor. In PS I, the precursor lifetime (290ns) is much longer than the characteristic time of singlet-triplet mixing at × band (9 GHz, 3 kG) and K band (24 GHz, 8 kG). As a result, the observable net polarization decreases with the field strength in this region. In contrast, in heliobacteria, the precursor lifetime (600 ps) is much shorter than the characteristic time of singlet-triplet mixing, and the net polarization increases in the same range of Zeeman energies. The polarization patterns in these two systems can be described using the specific limiting cases of a short lived and long lived precursor radical pair and written as a sum of several contributions. The spectra are simulated on this basis using parameters derived entirely from independent experimental data, and good agreement between the experimental polarization patterns is obtained. The calculated polarization patterns are sensitive to spin dynamics on a timescale much shorter than the spectrometer response time, and the expected influence of a 10 ns component in the electron transfer, as observed optically in some PS I, preparations is discussed. No significant influence from such a component is found in the spin polarization patterns of PS I from the cyanobacterium Synechocystis 6803.