Antibacterial TAP-mimic electrospun polymer scaffold: effects on P. gingivalis-infected dentin biofilm

Objectives

This study sought to investigate, in vitro, the effects of a recently developed triple antibiotic paste (TAP)-mimic polymer nanofibrous scaffold against Porphyromonas gingivalis-infected dentin biofilm.

Materials and methods

Dentin specimens (4 × 4 × 1 mm³) were prepared from human canines. The specimens were sterilized, inoculated with P. gingivalis (ATCC 33277), and incubated for 1 week to allow for biofilm formation. Infected dentin specimens were exposed for 3 days to the following treatments: antibiotic-free polydioxanone scaffold (PDS, control), PDS + 25 wt% TAP [25 mg of each antibiotic (metronidazole, ciprofloxacin, and minocycline) per mL of the PDS polymer solution], or a saturated TAP-based solution (50 mg of each antibiotic per mL of saline solution). In order to serve as the negative control, infected dentin specimens were left untreated (bacteria only). To determine the antimicrobial efficacy of the TAP-mimic scaffold, a colony-forming unit (CFU) per milliliter (n = 10/group) measurement was performed. Furthermore, additional specimens (n = 2/group) were prepared to qualitatively study biofilm inhibition via scanning electron microscopy (SEM). Statistics were performed, and significance was set at the 5 % level.

Results

Both the TAP-mimic scaffold and the positive control (TAP solution) led to complete bacterial elimination, differing statistically (p < 0.05) from the negative control group (bacteria only). No statistical differences were observed for CFU per milliliter data between antibiotic-free scaffolds (2.7 log₁₀ CFU/mL) and the negative control (5.9 log₁₀ CFU/mL).

Conclusions

The obtained data revealed significant antimicrobial properties of the novel PDS-based TAP-mimic scaffold against an established P. gingivalis-infected dentin biofilm.

Clinical relevance

Collectively, the data suggest that the proposed nanofibrous scaffold might be used as an alternative to the advocated clinical gold standard (i.e., TAP) for intracanal disinfection prior to regenerative endodontics.

     

Physical and functional independency of p70 and p58 natural killer (NK) cell receptors for HLA class I: their role in the definition of different groups of alloreactive NK cell clones.

Natural killer (NK) cells express clonally distributed receptors for different groups of HLA class I alleles. The Z27 monoclonal antibody described in this study recognizes a p70 receptor specific for HLA-B alleles belonging to the Bw4 supertypic specificity. Single amino acid substitutions in the peptide-binding groove of HLA-B2705 molecules influenced the recognition by some, but not all, p7O/Z27+ clones. This suggests the existence of a limited polymorphism within the p7O family of receptors. The pattern of reactivity of monoclonal antibody Z27 revealed that Bw4-specific receptors may be expressed alone or in combination with different (GL183 and/or EB6) p58 molecules. Analysis of NK clones coexpressing p58 and p7O receptors allowed us to demonstrate that the two molecules represent physically and functionally independent receptors. The expression of p7O molecules either alone or in combination with EB6 molecules provided the molecular basis for understanding the cytolytic pattern of two previously defined groups of "alloreactive" NK cell clones ("group 3" and "group 5").     

The association of thrombocytopaenia and Lyme disease.

The association of asymptomatic thrombocytopaenia in six patients with acute Lyme disease is described. Recovery from thrombocytopaenia occurred shortly following antibiotic therapy. Patients residing in endemic areas for Lyme disease who present with flu-like symptoms and laboratory findings of thrombocytopaenia should prompt suspicion of acute Lyme disease. Appropriate clinical studies should be undertaken to confirm the diagnosis.     

Isolation of pig pancreatic islets by a new method with hydraulic shaking: preliminary report

The limited availability of human pancreas represents a serious problem in islet transplantation. In the past few years many efforts have been made to isolate pancreatic islets from large mammals in order to achieve valid and reproducible isolation methods [1–4]. For several reasons swine may be considered an ideal source of islet tissue because of the similarity between human and porcine insulin and because of the easy availability of pig pancreata. Some papers have been published recently on this topic with good results [1, 5–7]. However, some problems, such as islet dissociation into single cells after collagenase digestion, are not completely solved. In this article, an automated method involving a hydraulic shaking system is described for islet isolation from the pig pancreas, developed in our laboratory and derived from Ricordi's model.     

Importance of early diagnosis in the improvement of prognosis in breast carcinoma: non-palpable lesions. Preliminary results

There are still marked differences in the current indications for breast screening proposed by the various international school of oncology. Epidemiological data to the effect that breast screening in asymptomatic women aged over 50 reduces the death rate due to breast cancer now appears to be widely accepted, but an analogous finding for women aged between 40-49 has not yet been confirmed. Following a brief analysis of the most important breast screening programmes carried out to date, the Authors report the preliminary results regarding the identification and biopsy of non-palpable breast lesions during the course of a screening programme in 1986 by the Dept. of Cancer Surgery. Of a total of 1128 breast scans in asymptomatic patients aged between 40 and 73, 24 suspect (1.9%) non-palpable lesions were found of which 5 (20.8%) proved to be carcinomas.