Magnetic Circular Dichroism of meso-Phenyl-Substituted Pd-Octaethylporphyrins

Absorption and magnetic circular dichroism (MCD) spectra have been measured and theoretically simulated for a series of palladium octaethylporphyrins substituted at the meso positions with phenyl groups (n = 0-4). Analysis of the spectra included the perimeter model and time-dependent density functional theory (TDDFT) calculations. With the increasing number of phenyl substituents, the molecule is transformed from a positive hard (ΔHOMO > ΔLUMO) to a soft (ΔHOMO ≈ ΔLUMO) chromophore. This is manifested by a drastic decrease of the absorption intensity in the 0-0 region of the Q-band and by the strongly altered ratio of MCD intensities in the Q and Soret regions. Such behavior can be readily predicted using perimeter model, by analyzing frontier orbital shifts caused by various perturbations: alkyl and aryl substitution, insertion of a metal, and deviations from planarity. TDDFT calculations confirm the trends predicted by the perimeter model, but they fail in cases of less symmetrical derivatives to properly reproduce the MCD spectra in the Soret region. Our results confirm the power of the perimeter model in predicting absorption and MCD spectra of large organic molecules, porphyrins in particular. We also postulate, contrary to previous works, that the isolated porphyrin dianion is not a soft chromophore, but rather a strongly positive-hard one.

Activity of Zn and Mg phthalocyanines and porphyrazines in amyloid aggregation of insulin

Formation of the deposits of protein aggregates—amyloid fibrils in an intracellular and intercellular space—is common to a large group of amyloid‐associated disorders. Among the approaches to develop of therapy of such disorders is the use of agents preventing protein fibrillization. Polyaromatic complexes—porphyrins and phthalocyanines—are known as compounds possessing anti‐fibrillogenic activity.

Here, we explore the impact of related macrocyclic complexes—phthalocyanines (Pc) and octaphenyl porphyrazines (Pz) of Mg and Zn—on aggregation of amyloidogenic protein insulin. Pz complexes are firstly reported as compounds able to affect protein fibrillization.

The effect of Pc and Pz complexes on the kinetics and intensity of insulin aggregation was studied by the fluorescent assay using amyloid sensitive cyanine dye. This has shown the impact of metal ion on the anti‐fibrillogenic properties of macrocyclic complexes—the effect on the fibrillization kinetics of Mg‐containing compounds is much more pronounced comparing to that of Zn analogues.

Scanning electron microscopy experiments have demonstrated that filamentous fibrils are the main product of aggregation both for free insulin and in the presence of macrocyclic complexes. However, those fibrils are distinct by their length and proneness to lateral aggregation. The Pc complexes cause the increase in variation of fibrils length 0.9 to 2.7 nm in opposite to 1.4 to 2.0 nm for free insulin, whereas Pz complexes cause certain shortening of the fibrils to 0.8 to 1.6 nm.

The averaged size of the fibrils population was estimated by dynamic light scattering; it correlates with the size of single fibrils detected by scanning electron microscopy.

Resonance Raman spectroscopy study of protonated porphyrin

Resonance Raman microscopy was used to study the resonance Raman scattering of the diacid (diprotonated form) of free-base porphyrin (21H,23H-porphine) in a crystal powder and KBr pellets. Intensive lines in the spectral range between 100÷1000cm^-1 have been detected and assigned as spectral manifestation of out-of-plane modes. The Raman spectra were simulated by means of DFT methods and compared with the experimental data. It is evident from experimental and theoretical results that the activation of out-of-plane modes arises from saddle distortion of the porphyrin macrocycle upon formation of its diprotonated form.

Increased mRNA Expression of Transforming Growth Factor Beta in the Arterial Wall of Chronically Rejected Renal Allografts in Humans

INTRODUCTION

Transforming growth factor beta (TGF-beta) has an established role in interstitial damage of renal transplants during chronic rejection (CR). However, its involvement in transplant vasculopathy is not clear. The aim of the study was to assess TGF-beta gene expression in the walls of large-caliber arteries within chronically rejecting renal allografts. We evaluated associations between gene expression of this factor and intimal thickness or clinical data.

MATERIAL AND METHODS

Renal artery samples of kidney allografts were obtained from 20 hemodialysis patients with end-stage renal graft disease due to CR, who were undergoing graftectomy. The control group included 32 hemodialysis patients with end-stage renal disease, undergoing nephrectomy due to autosomal dominant polycystic kidney disease (n = 12), chronic pyelonephritis (n = 13), or kidney limited tumor (n = 7). Gene expression of TGF-beta was measured using real-time PCR.

RESULTS

TGF-beta mRNA expression was 3.25-fold higher in CR than in control patients (P < .001). Expression of mRNA for this cytokine was not influenced by the following factors: intimal thickness; age; serum cholesterol, triglycerides and glucose; BMI; graft survival; time of dialysis before transplantation; total ischemic time; immunosuppressive regimen; incidence of acute rejection episode; panel reactive antibodies; and period of dialysis before graftectomy. TGF-beta is involved in neointimal formation in CR.

New insights into the possible role of bacteriophages in transplantation

Due to the increasing prevalence of drug-resistant bacterial infections in the "post-antibiotic era," bacteriophages (bacterial viruses, BP) may be useful to administer to transplant recipients without exposing them to an increased risk of rejection, which occurs consequent to some viral infections. Herein we present evidence that at least some coliphages (T4) do not pose such risk. Interestingly, they may produce immunosuppressive effects extending transplant survival. Our data suggest that BP may be used in clinical transplantation to treat drug-resistant bacterial infections and perhaps as an adjunct to immunosuppressive therapy.

Antitumor activity of bacteriophages in murine experimental cancer models caused possibly by inhibition of beta3 integrin signaling pathway

Bacteriophages (phages) as bacterial viruses are generally believed to have no intrinsic tropism for mammalian cells. In this study the interactions between phages and various eukaryotic cells were investigated. Binding of phages to the membranes of cancer and normal blood cells was observed. Moreover, it was shown that the wild-type phage T4 (wtT4) and its substrain HAP1 with enhanced affinity for melanoma cells inhibit markedly and significantly experimental lung metastasis of murine B16 melanoma cells by 47% and 80%, respectively. A possible molecular mechanism of these effects, namely a specific interaction between the Lys-Gly-Asp motif of the phage protein 24 and beta3-integrin receptors on target cells is proposed. It was also shown that anti-beta3 antibodies and synthetic peptides mimicking natural beta3 ligands inhibit the phage binding to cancer cells. This is in line with the well-described beta3 integrin-dependent mechanism of tumor metastasis. It is concluded that the blocking of beta3 integrins by phage preparations results in a significant decrease in tumor invasiveness.

The biological functions of beta3 integrins

Integrins comprise a large family of alphabeta heterodimeric cell-surface receptors that are found in many animal species. They are expressed on a wide variety of cells. There are two members in the beta3 integrin family: alphaIIb beta3 and alpha(v)beta3. This class of adhesion receptors mediates cell-cell and cell-extracellular matrix interactions. Dysregulation of the beta3 integrins is involved in the pathogenesis of many diseases (including cancer) and in transplant rejection. Integrins also play a key role in many virus infectious cycles. In this paper the biological functions of the beta3 family are reviewed, with particular interest in its role in cancer progression and metastasis.

Mutations in bacteriophage T4 genome

Bacteriophage (phage) T4 belonging to T-even phages is one of the best known phages with a completely deciphered genome sequence. As a model of living systems, T4 phage has many technical advantages. It can be very easily grown in large quantities, manipulated by classical genetics, and engineered by site-directed mutagenesis. Many substances have been first tested for mutagenicity in T-even phages. The results of these tests were very often applicable to higher organisms due to similar mechanisms of mutagenesis. T4 phage is also important in phage therapy, which represents an alternative treatment of bacterial infections since the bacterial resistance to antibiotics has become a serious medical problem. The site-directed mutagenesis is a method that enables to introduce mutations which can influence phage affinity to bacteria and can be a practical technique for enriching phage collections and for widening specificity of phages for new bacterial strains now insensitive to phage therapy.

Vibrations of the phenoxyl radical

Phenoxyl radical (C(6)H(5)O) was prepared photochemically in low-temperature argon matrices. The infrared absorption spectra were obtained for C(6)H(5)O and for the isotopically labeled species C(6)D(5)O and 1-(13)C(12)C(5)H(5)O. All but one IR-active fundamental vibrations were detected, most of them not previously observed. Combination of results from IR linear dichroism measurements on photooriented samples, determination of absolute IR intensities with the help of internal standards, analysis of isotopic shifts, and quantum chemical predictions (B3LYP/cc-pVTZ) led to a detailed assignment of phenoxyl radical vibrations. Significant frequency shifts are observed with respect to previously reported data based on resonance Raman studies in polar solutions. For some vibrations, these shifts reflect environment-induced structural changes, such as increase of the quinoid character of the phenoxyl radical in polar media. In particular, the frequency of the CO stretching vibration, readily observable in both IR and Raman experiments, is extremely sensitive to the environment and can thus be used to probe its polarity.

DNA profiling of trace evidence--mitigating evidence in a dog biting case

A young girl was the victim of a severe dog attack. An animal, suspected of having caused the attack, was later impounded for investigation. Microclots of blood, recovered from the dog's fur, were analyzed by STR DNA. Results showed that this blood was not related to the biting. Other forensic evidence--hairs, fibers, and odontology--failed to connect a particular animal to the attack. The implications of these findings for the dog and its owners are discussed as well as other forensic methods for resolving such cases.

Three different autoimmune bullous diseases in one family: is there a common genetic base?

We report an unusual familial occurrence of autoimmune bullous diseases. Three members of a family suffered from three different autoimmune bullous diseases: pemphigus vulgaris (PV), linear IgA disease (LAD) and cicatricial pemphigoid (CP). The HLA type was determined in five family members: all were positive for HLA-DQ5/DR6, which is reported to be associated with susceptibility to PV. The CP patient was DQ7(3) positive, which is in concordance with enhanced susceptibility to ocular CP and CP. The LAD patient was B8 and DR3 negative but positive for HLA-A1. Our study supports the hypothesis that there is a genetically transmitted susceptibility to autoimmune bullous diseases but that additional factors seem necessary actually to develop a particular disease.

T cell interactions with extracellular matrix proteins in patients with thyroid-associated ophthalmopathy

Although thyroid-associated ophthalmopathy (TAO) is now generally accepted as an autoimmune inflammatory disorder of the extraocular muscles and the orbital connective tissue, its aetiopathogenesis remains poorly understood. Recent data indicate that impaired interactions between T cells and extracellular matrix (ECM) proteins may play an important role in development and maintaining of an inflammatory process. We report here results of the study focusing on interactions between T lymphocytes and collagen-I (Coll-I), collagen-IV (Coll-IV), fibronectin (FN), laminin (LM) in patients with TAO. Using a standard peripheral blood mononuclear cells (PBMC) proliferation assay, we observed a markedly enhanced T cell response to Coll-I in patients with active TAO (mean SI=4.5). The proliferatory response to Coll-I was significantly greater (Wilcoxon test; p < 0.001) than in normal subjects (mean SI=1.88), patients with stable TAO (mean SI=2.05) and patients with thyroid autoimmune diseases (AITD) without ophthalmopathy (mean SI=2.49). PBMC stimulation by Coll-I is likely to be antigen-dependent requiring engagement of the T cell receptor with collagen peptides, rather than mediated via integrins. The percentage of circulating CD29+ (beta1 integrin chain) T cells was not increased in patients with active TAO. Additionally in the assay of costimulation of CD3-mediated proliferation, we found that peripheral blood T cells from patients with TAO and AITD were costimulated only by FN. On the other hand a markedly enhanced costimulation of CD3-mediated proliferative responses by Coll-I, Coll-IV, FN and LM were observed in a retrobulbar T cell line. We conclude that abnormalities in T cell interactions with ECM proteins, especially Coll-I may play a role in the pathogenesis of TAO.

Modulation of CD3-dependent lymphocyte proliferation by extracellular matrix proteins in atopic dermatitis

Patients with atopic dermatitis were found to have an about 7-fold increased spontaneous proliferative response of peripheral blood lymphocytes and an about 4-fold elevation of CD3-dependent lymphocyte transformation as compared to normal controls. The CD3-dependent lymphocyte response in patients with severe atopic dermatitis lesions was increased to a lower degree than in those with mild skin lesions. Despite a highly increased CD3-dependent lymphocyte response, the extracellular matrix proteins could induce further co-stimulation of lymphocytes in patients with atopic dermatitis, similar to that in normal controls. However, co-activation by type IV collagen was markedly increased in patients with severe lesions, whereas co-stimulations by both type I collagen and fibronectin were decreased in patients with mild lesions. This finding reflects presumably the changes in lymphocyte subpopulations and their activities related to the recirculation of these cells through the active skin lesions and to the contact of T cells with extracellular matrix proteins. The percentage of CD26-positive lymphocytes was also significantly (p < 0.05) increased in patients with severe atopic dermatitis. These data indicate that helper T cells are excessively activated in atopic dermatitis and that the function of beta-1-integrin receptors underlying the extracellular matrix protein-mediated co-activation of CD3-dependent lymphocyte responses is modified by disease severity.

Excessive costimulation of CD3-dependent lymphocyte response by extracellular matrix proteins in severe widespread psoriasis

Costimulation of anti-CD3-triggered proliferative T-cell responses by type I and type IV collagen and fibronectin was studied in 25 patients with psoriasis and 12 healthy subjects. The stimulation index of anti-CD3-mediated responses in the presence of type I collagen was about half that in the controls. Although the CD3-dependent proliferative response of psoriatic lymphocytes in patients with active widespread plaque psoriasis was reduced by about 50%, costimulatory responses induced by type IV collagen and fibronectin were found to be enhanced in relation to the controls. The degree of costimulation by type IV collagen and fibronectin was related to disease severity. The highest values of the stimulation index were found in patients with a PASI greater than 24, skin involvement of more than 40% of body surface area, and a duration of psoriatic lesions of more than 3 months. The results indicated that in active widespread plaque psoriasis subpopulations of T cells bearing receptors for some extracellular matrix proteins were increased in the peripheral blood. A factor responsible for this phenomenon may be trafficking of T cells through the basement membrane zone of psoriatic lesions, which presumably causes modification of T cell immunological responsiveness after recirculation.

Wall hangings, hairs and the Holocaust

Two wall hangings, from the time of the Second World War, were reportedly made from human hair. Laboratory examination of the hangings confirmed this fact. Fibers, holding the wall hangings together, and the weave of the hangings were also examined. Results and implications of the findings are discussed.