On the negligible impact of ruffling on the electronic spectra of porphine, tetramethylporphyrin, and perfluoroalkylporphyrins.

In the first part of this paper, the syntheses, structural characterization, molecular modeling, and electronic spectra for planar and nonplanar perfluoroalkylated porphyrins, (R(f))(4)P's, are reported. These studies demonstrate that the intrinsic substituent effect of the perfluoroalkyl group on the long-wavelength electronic spectrum of porphyrins is substantial, and similar (in magnitude) to that of a phenyl ring. Moreover, it is shown that out-of-plane distortion of (R(f))(4)P's has a negligible impact on their electronic spectra. These data bolster the findings of our earlier work and demonstrate that nonplanarity of (R(f))(4)P's does not result in a red-shift in their optical spectra. In the second part of this paper, time-dependent density functional spectral calculations (B3LYP/6-311G/TD) for porphine, 5,10,15,20-tetrakis(trifluoromethyl)porphyrin, and 5,10,15,20-tetramethylporphyrin in a variety of ruffled conformations are reported. The results of these studies indicate that (1) substantial ruffling of porphyrins has a negligible effect upon their electronic spectra, (2) similarly small effects upon electronic spectra are predicted if electron-withdrawing or electron-releasing groups decorate the porphyrin periphery, (3) for sterically encumbered porphyrins, ruffling can actually result in hypsochromic shifts in various absorption bands, and (4) the bulk of the red-shift commonly thought to be due to nonplanar distortion actually arises from other substituent effects. These results pose serious challenges to previous theoretical and empirical studies that have sought to find a cause-and-effect relationship between nonplanarity and electronic spectra in porphyrins.

Atherosclerotic lesion of the circle of Willis: its study applying an atherometric system using multivariate statistical techniques.

In 2043 autopsies divided into the high (HAG) and low (LAG) atherosclerosis group a set of variables of a new atherometric system (AS) was used to characterize the atherosclerotic lesion (AL) in the circle of Willis arteries: fatty streaks (X), fibrous plaques (Y), severe plaques (Z), index of stenosis (P) and index of benignity (B). Principal component analysis identified a first component of severity (Y, P and Z) and a second component of benignity (X and B). Fibrous plaques play the main role in the severity of AL in the circle of Willis. The new AS proved its usefulness in characterizing the state of AL, whereas discriminant analysis and AS distinguished between the HAG and the LAG. The classification was correct in 74.5% and 76.5% when using three (X, Y, Z) and five (X, Y, Z, P, B) variables, respectively.

Atherosclerotic lesion of the aorta: its study applying a biometric system using multivariate statistical techniques.

UNLABELLED: To study the atherosclerotic lesion (a.l.) in the two aorta segments (thoracic and abdominal) in a given set of autopsies (total 2043) performed during five years (1981-85) in one of the principal general hospitals in the city of Havana, a set of five variables was used as part of a new biometric system (BS), to characterize the a.l. in any vascular sector. Three of these variables represent the main types of a.l., fatty streaks (X), fibrous plaques (Y) and severe (complicated and calcified) plaques (Z), while the others were indices of stenosis (P) and benignity (B). Classical dissection and pathological laboratory procedures were performed. Qualitative and quantitative gross morphometric analyses were done by a digitilizer joined to a NEC (9801) personal microcomputer (Japan). These data were processed in a medium size computer EC-1040 (GDR). The multivariate statistical techniques, the principal component analysis (PCA) and the discriminant analysis (DA), were used applying the "SPSS" programme. CONCLUSIONS: (1) PCA revealed in the two aorta segments studied a first component of benignity, fatty streaks (X) and benignity index (B) and a second component of severity, severe plaques (Z) and stenosis number (P). Because of the dimensions of the two aorta segments (width and length) the dominant, first component, is benignity. So the BS is useful in characterizing and describing the lesional state of any aorta segments; (2) DA and BS proved to be useful to distinguish between the high atherosclerotic group (HAG) and the low atherosclerotic group (LAG). The correct classification rate exceed in all cases 70%. The three components of the lesional state vector (X,Y,Z) distinguish the groups. The stenosis (P) and benignity (B) indices proved to be most relevant. The sign of benignity index is always the same as that of the LAG. Thus this variable truly represents benignity. The coherence and consistency of the BS was also proved by DA.

Interspecific interaction of aortic endothelial and smooth muscle cells.

The proliferation stimulating or inhibitory effect of aortic endothelial cells on aortic smooth muscle cells and vice versa was studied in cell culture by using a newly developed co-cultivation technique. The effect was registered as the incorporation of labelled thymidine detected by liquid scintillation counting. The experiments were performed in intra and interspecific combinations, using bovine, pig or rat aortic cell cultures. The endothelial cells stimulated smooth muscle cell proliferation in a species specific way. In interspecies combinations either inhibition or no effect was observed. The smooth muscle cells usually had an inhibitory effect on the proliferation of endothelial cells except for the pig smooth muscle cells which had a stimulatory effect in both inter and intraspecies combinations. Co-cultivation of smooth muscle or endothelial cells with cells of the same type resulted mostly in inhibition or no effect in both intra and interspecies combinations. This phenomenon was particularly conspicuous with endothelial cells. The different stimulatory and inhibitory effects produced by these cells may play an important role in the regulation of neovascularization and in reendothelization of denuded intimal areas.

The lesional state vector: a new approach to characterize atherosclerotic lesions.

A new approach to study the atherosclerotic lesions (AL) applying a vectorial system is presented. The "lesional state vector" (LSV) is formed by using as vectors the three main types of AL, e.g. fatty streak, fibrous plaque and severe plaque (complicated and calcified considered together) as the coordinates. This vectorial representation is part of a biometric system described in 1982 by Carlevaro and Fernández-Britto, to characterize the AL in any vascular sector or group of patients. The LSV is a suitable tool to study the AL since it conserves all the information available as primary data and it is extremely useful for comparative studies applying different statistical techniques, including multivariate approaches. To demonstrate its advantage, we studied the coronary vessels (right, left anterior descending and left circumflex arteries), the cerebral arteries (circle of Willis) and the aorta (thoracic and abdominal segments) in 2,043 autopsies performed during 5 years (1981-1985). The patients were classified according to the primary cause of death, as high atherosclerotic (HAG) or low atherosclerotic groups (LAG), comprising 1,171 and 872 cases, respectively. Qualitative and quantitative gross analysis were done by a digitizer joined to a personal computer (NEC 9801, Japan). These data were processed on computer ES 1040, GDR. The statistical techniques applied (including the multivariate analysis) were those available in the Statistical Package for Social Sciences (SPSS). Applying the LSV to the arteries studied it was found that in the coronary arteries and in the circle of Willis, the severe plaque and the fibrous plaque played the most important roles, respectively. Graphic representation can make differentiation between HAG and LAG easy.(ABSTRACT TRUNCATED AT 250 WORDS)

Examination of a spontaneously transformed aortic smooth muscle cell line. I. Morphological examinations.

Spontaneous transformation was observed of a mini-pig aortic smooth muscle cell line in its 21st passage in vitro. The transformed cells exhibited changed phenotype, heteroploidy and excessive proliferative activity. The initially elongated cells developed a polymorphous essentially polygonal appearance. The longitudinal filaments characteristic of normal cells disappeared and only finely granular double refracting matter was detectable in polarized light. The transformed cells exhibited microvilli in both transmission electron microscopic and scanning electronmicroscopic preparations. The appearance of spontaneous lectin binding in the transformed cells is a sign of altered plasma membrane structure. The possible contaminational origin of the transformed cells was carefully excluded.

Metastable equilibrium with random local fluctuations: simulations of dynamic receptor pattern generation in a fluid mosaic membrane.

The generation of receptors in the animal cell's membrane was simulated by a model consisting of units in four possible states within a hexagonal area (playboard) of n units of a triangular network. The state of each unit was determined by the previous state of itself and of its six nearest neighbours, as regulated by a set of transition rules, which kept the mean relative frequency (m.r.f.) of each state constant. The transition rules were applied to the system exactly n times, regardless whether this involved selection of a unit on 0, 1, 2 or more occasions (programme "random selection with repeat"; RS-R). Comparison to previous results obtained by other ways of application of the rules has shown that the RS-R programme accounted for the highest m.r.f. of quiet (Q) units and Q clusters (sub-patterns), and also for the longest survival of Q configurations through several generations. Functioning of the model under the RS-R programme simulates an integrated system in metastable equilibrium with random local fluctuations, such as the cytoplasmic membrane is imagined to be in standardized environmental conditions. The formation-persistence-disintegration cycle of the sub-patterns is believed to simulate the dynamic generation of transitory receptor configurations in the cell membrane.

An advanced version of the dynamic receptor pattern generation model: the flux model.

In the recently described simple model of dynamic receptor pattern generation we used a two dimensional hexagonal area of a regular triangular network, formed by a statistically constant distribution of unit electostatic changes in a dynamic equilibrium. A set of 16 trnasition rules was applied to all units simultaneously; the next state of each unit depended only on the previous state of its six nearest neighbours, and the transition of the total pattern into the new one occurred in a single jump. Hence we designated the initial simple model as "jump model". In this paper we described an advanced version of the model, in which simplified rules are applied to one unit after the other in a sequential order, from left to right, starting with the top row of units. In the advanced version the state of a unit depends not only on that of its six nearest neighbours, but also on the state of all units preceding in sequence the one actually considered. This results in flux-like transitions. We therefore designated the advanced version as the "flux model". It is shown that the flux model represents a closer approximation of physical and biological realities than the original jump model.

Measles virus induced lectin binding in cultured, aortic cells.

Using the indirect hemadsorption test it was shown that cultured diploid cells of mini-pig, monkey or human aortic origin develop wheat germ lectin/WGA/binding capacity following infection with measles virus. Heteroploid cell lines of similar origin have bound WGA also without being infected with virus. The possible role of virus induced membrane changes in vascular cell pathology is suggested by the results presented.

Chromosome changes in subacute sclerosing panencephalitis.

In two out of a total of 6 cases of subacute sclerosing panencephalitis with manifest chromosome alterations, chromosome studies were repeated 4 and 5 years of standing, respectively, after manifestation of the disease. In one case the incidence of chromosome alterations increased while in the other no change was found. Both cases were clinically similar in their history with remission.

Influence of membrane active substances on cell surface morphology of cultured aortic endothelial cells.

1. The changes occurring on the surface of cultured aortic endothelial cells under the influence of exogenous cholesterol, lysolecithin, or cholesterol + lysolecithin were pursued by scanning and transmission electron microscopy. 2. Both compounds were found to cause surface changes under different quantitative relations, as shown by scanning electron microscopy of unfixed preparations. The changes were less significant in preparations fixed prior to the scanning--or transmission electron microscopic examination. 3. Other cell lines maintained in this laboratory and similarly treated with cholesterol, were found to be less responsive than the endothelial cells. 4. Cholesterol content was determined by thin layer chromatography in six different cell lines, before and after the addition of cholesterol. Only the endothelial cells showed a notable rise of cholesterol content after treatment. This fact may confirm our finding that cholesterol induced morphological changes were demonstrable only in the endothelial cells.

Scanning electron microscopic examination of in vitro cultured cells by different methods.

1. The morphology of cultured aortic endothelial cells was studied by scanning electron microscopy. The cells were prepared for examination by three different procedures: two involved fixation, the third only drying in vacuum. 2. To check the efficiency of the methods of preparation, three non-endothelial cell lines were processes similarly and examined for SEM morphology. 3. The images of the cell surfaces were found to differ depending on the method of preparation and the value of the methodical approach clearly varied with the type of the cell. It is concluded that for studying cell morphology by SEM the method of preparation should carefully be selected.

In vitro cultivation and identification of aortic endothelium from miniature pig.

Pieces of miniature pig aorta were explanted endothelial face down directly on the bottom of Petri dishes. On removal of the aorta fragments after 2-4 days of incubation single cells or small groups of viable endothelium were found attached. The cells developed into a permanent line (at present over 18 passages) and were identified as pure endothelial cells both by light- and electron microscopic examination.

Chromosome aberrations in cells infected with various strains of measles virus.

The incidence of chromosome fragmentation and/or breakage has been studied in cultured human embryonic diploid cells infected with different wild and vaccinal strains of measles virus. It seemed that for wild strains the mean incidence of fragmentation was two times higher, that of breakage two times lower than for the vaccinal strains.

A guanidine-sensitive step of the poliovirus RNA replication cycle.

It has been shown that the amount of viral RNA synthesized in synchronized HeLa cells 0-2 h after infection does not notably vary during the mitotic cycle. However, the amount of viral RNA synthesized 2-4.5 h after infection exhibited a sharp maximum in S-phase cells. Guanidine inhibited the incorporation of 3-H-uridine into the viral RNA synthesized 2-4.5 h after infection only in cells in the S-phase. It had no demonstrable effect on viral RNA synthesis 0-2 h after infection in cells in any phase of the mitotic cycle. Thus, additional indirect evidence has been presented in favor of the hypothesis that two different replicases or two different conformations of one enzyme are involved in poliovirus RNA replication. The one functioning 0-2 h after infection is cycle-independent and guanidine-sensitive, whereas the other functions exclusively in phase-S cells 2-4.5 h after infection and is inhibited by guanidine.