Reply to the ‘Comment on “Metal–organic green dye: chemical and physical insight into a modified Zn-benzoporphyrin for dye-sensitized solar cells”’ by R. Steer, RSC Advances, 2018, DOI: 10.1039/c8ra00213d

The authors reply to the comment by R. P. Steer discussing the reasons for their incorrect assignment of the luminescence decay of the novel compound 5,10,15-(triphenyl),20-[ethynyl-(4-carboxy)phenyl]tetrabenzoporphyrinate Zn(ii) (PETBP). Further DFT and TDDFT calculations have been performed on the compound to investigate the possibility of a direct S₂–S₀ decay instead of a S₂–S₁ conversion with a subsequent emission to the ground state. In addition, the presence of traces of very luminescent contaminants of the ring-opened type has been considered on the grounds of calculated absorption and fluorescence spectra. The results of these investigations confirm that the S₂–S₀ emission reported in the commented paper is not attributable to the target molecule but rather to a neglected luminescent impurity.

The authors reply to the comment by R. P. Steer discussing the reasons for their incorrect assignment of the luminescence decay of the novel compound 5,10,15-(triphenyl),20-[ethynyl-(4-carboxy)phenyl]tetrabenzoporphyrinate Zn(ii) (PETBP).

TCR Vβ repertoire in an Italian longeval population including centenarians

During the last years, the hypothesis that aging and diseases are two distinct phenomena, and that successful aging is possible for most humans, has been put forward. We studied the TCR Vβ repertoire of T lymphocytes of healthy longevals and centenarians as crossing point of genetic predisposition and environmental effects to longevity, using the Spectra-typing method. TCR Vβ1, Vβ8, and Vβ20 were found to be expanded in the longeval population, compared with the younger control population. This repertoire can have been shaped by the selective action of particular HLA alleles, or by the clonal expansion of specific T cell clones, able to modulate the immune response to endogenous and exogenous antigens. Moreover, the skewed Vβ usage and the clonal expansion seem to be the effects of physiological changes occurring with aging and not pathological signs of malignity.

Regulatory influence of scaffolds on cell behavior: how cells decode biomaterials

A stem cell is defined as a cell able to self-renew and at the same time to generate one or more specialized progenies. In the adult organism, stem cells need a specific microenvironment where to reside. This tissue-specific instructive microenvironment, hosting stem cells and governing their fate, is composed of extracellular matrix and soluble molecules. Cell-matrix and cell-cell interactions also contribute to the specifications of this milieu, regarded as a whole unitary system and referred to as "niche". For many stem cell systems a niche has been identified, but only partially defined. In regenerative medicine and tissue engineering, biomaterials are used to deliver stem cells in specific anatomical sites where a regenerative process is needed. In this context, biomaterials have to provide informative microenvironments mimicking a physiological niche. Stem cells may read and decode any biomaterial and modify their behavior and fate accordingly. Any material is therefore informative in the sense that its intrinsic nature and structure will anyway transmit a signal that will have to be decoded by colonizing cells. We still know very little of how to create local microenvironments, or artificial niches, that will govern stem cells behavior and their terminal fate. Here we will review some characteristics identifying specific niches and some of the requirements allowing stem cells differentiation processes. We will discuss on those biomaterials that are being projected/engineered/manufactured to gain the informative status necessary to drive proper molecular cross-talk and cell differentiation; specific examples will be proposed for bone and cartilage substitutes.

X-ray Absorption Spectroscopy Studies of Ruthenoxane Phthalocyanine Derivative HO-[(Pc)RuO](n)()-H

Comprehensive EXAFS investigation carried out on ruthenoxane phthalocyanine and on its chemical precursors ruthenium phthalocyanine dimer and ruthenium bis-pyridine phthalocyanine are reported. The distances around the ruthenium atom were obtained by data analysis and confirm the structural models already proposed for the first two compounds and indicate two pyridines axially coordinated to the central metal for the adduct.

TCR repertoire of suppressor CD8+CD28- T cell populations

The cellular basis of graft rejection and the development of strategies for specific suppression of T cell responses against allogeneic and xenogeneic transplants represents an area of active investigation. Recently, a population of MHC-class I restricted CD8+CD28- T suppressor cells (Ts) which are able to inhibit specifically the proliferative response of allospecific, xenospecific and nominal-antigen specific CD4+ T helper cells (Th) has been identified. We have studied the TCR V beta gene repertoire expressed by CD8+CD28- Ts isolated from allospecific, xenospecific, and nominal antigen-specific T cell lines (TCL). A limited V beta repertoire has been found in all TCLs studied. The most restricted TCR V beta usage was observed within the population of Ts from xenospecific TCLs. The TCR V beta usage within the Ts subset of TCL differs from the TCR repertoire expressed by the CD4+ Th subset of the same TCL. This is consistent with the fact that Ts and Th cells recognize distinct MHC/ antigen complexes. The finding that the TCR repertoire used by Ts is limited opens new avenues for studying the mechanisms of transplant rejection.

Chromosome 6p-encoded HLA-DR2 determination discriminates migraine without aura from migraine with aura

Segregation analysis indicates that migraine without aura (MWoA) and migraine with aura (MWA) have multifactorial inheritance, but involved genetic and environmental factors are largely unknown. A controlled study was performed to assess the HLA-driven liability to migraine and to verify if the heterogeneity between MWoA and MWA is HLA-linked. Forty-five migraine patients (31 MWoA, 14 MWA) and 53 healthy blood donors as controls, coming from the same geographic area, were studied. Tissue typing was performed using the standard complement-dependent microlymphocytotoxicity technique for HLA Class I and by PCR-SSP (Sequences Specific Primers) typing for HLA Class II. Data emerging from the present study showed no altered distribution for HLA Class I A, B, C antigen frequency in migraine (MWoA, MWA) if compared to the control group. HLA Class II DR2 antigen showed a decreased frequency in MWA group if compared with both MWoA (p = 0.01) and control group (p = 0.039, RR = 0.21). These results seem to support the hypothesis of a protective role of DR2 antigen in MWA and provide additional basis for the proposed difference within MWoA and MWA.

Specific suppression of human CD4+ Th cell responses to pig MHC antigens by CD8+CD28- regulatory T cells

Evidence that T cells can down-regulate the immune response by producing or consuming certain cytokines or by lysing APCs or Th cells has been provided in various systems. However, the generation and characterization of suppressor T cell lines have met with limited success. Here we show that xenospecific suppressor T cells can be generated by in vitro stimulation of human T cells with pig APCs. Similar to allospecific suppressors, these xenospecific suppressor T cells carry the CD8+CD28- phenotype and react to MHC class I Ags expressed by the APCs used for priming. TCR spectratyping of T suppressor cells showed oligoclonal usage of TCR-Vbeta families, indicating that xenostimulation of CD8+CD28- T cells results in Ag-driven selection of a limited Vbeta repertoire. Xenospecific T suppressor cells prevent the up-regulation of CD154 molecules on the membrane of Th cells, inhibiting their ability to react against the immunizing MHC class II xenoantigens. The mechanism of this suppression, therefore, appears to be blockade of CD154/CD40 interaction required for efficient costimulation of activated T cells.

Induction of MHC-class I restricted human suppressor T cells by peptide priming in vitro

The induction of regulatory T cells may offer an effective means for specific immunosuppression of autoimmune disease and allograft rejection. The existence of suppressor T cells has been previously documented, yet their mechanism of action remains poorly characterized. Our studies demonstrate that T suppressor (Ts) cell lines can be generated by in vitro immunization of human PBMCs, with synthetic peptides or soluble proteins coupled to beads. Such Ts cells express the CD8+CD28- phenotype and show the following characteristics: (a) antigen specificity and restriction by self MHC Class I molecules; (b) limited TCR V beta gene usage; (c) ability to inhibit antigen-specific, MHC Class II restricted, Th proliferative responses; and (d) capacity to downregulate and/or inhibit the upregulation by Th of CD40, CD80, and CD86 molecules on APCs. The inhibitory activity of Ts on Th proliferation requires the tripartite interaction between Th, Ts, and APCs and results from inefficient costimulation of Th.

HLA and complement factors alleles sharing in Italian couples with recurrent spontaneous abortions

Recurrent Spontaneous Abortion (RSA) is postulated to be due to several factors including immunogenetic mechanisms. Many studies have been conducted on the effect of the MHC region in the reproductive phenomena suggesting an immunological or genetic involvement in RSA. We studied couples with 3 or more abortions among a larger group of couples in which female partners were anti-cardiolipin antibodies negative, resulting in a population of 43 couples typed for HLA-A, B, C, DR, DQ. In 16 of these 43 couples, complement factors C4A, C4B, and Bf were typed. The data shows a statistically significant increase of C4B*Q0 in RSA patients (N = 32) compared with the control population (N = 44) (pc = .00147) and also a statistically significant increase of C4B*Q0 sharing in aborting couples (43.75%) against the expected sharing rate in the control population (1.86%) (p < .001). Frequency increase of C4B*Q0 allele in aborting population leads to the hypothesis that an imbalance of complement factors expression and activity can have detrimental effects on implantation and embryo survival. Additionally, the significant sharing rate of C4B*Q0 in couples with RSA could indicate the existence of a gene in linked to this allele predisposing to RSA and acting in a recessive manner if present in double copies in the fetus.

HLA-DR and -DQ alleles in Italian patients with melanoma

Controversial data have been reported about HLA alleles and susceptibility to melanoma. Our investigation was undertaken to analyze the relationship between HLA alleles distribution in patients with melanoma and susceptibility to the tumor, in order to study the possible correlation between HLA class II DQA1, DQB1 and DRB1 genes involved in immune recognition, and melanoma, usually considered a highly immunogenic tumor. We therefore typed by means of PCR-SSP (sequence-specific primers) 53 Italian patients and 53 healthy random controls coming from the same geographic area. We observed a decrease of all haplotypes bearing DQB1*0301, DQB1*0302 and DQB1*0303 alleles but not of haplotype DRB1*11;DQA1*0501;DQB1*0301. Our results seem to support the hypothesis of a protective role of some DQ3-bearing haplotypic combinations in melanoma.

[Attrition of the mandibular bone caused by compression of the submandibular salivary gland. Description of a case]

A case of circumscribed reabsorption of the internal osseous lamina of the horizontal branch of the mandible, caused by compression of the submandibular salivary gland, is described. The picture, which recalled that of solitary bone cyst, is explained by reference to the fact that the mandible is of connective origin, and allows itself to be imprinted relatively easily by surrounding, adjacent anatomical formations during growth. In case of this kind, no treatment is required.