Short-chain fatty acids are a major by-product of anaerobic metabolism and can be detected in gingival fluid from periodontal pockets. Since most T cells are present subjacent to the pocket epithelium in conjunction with the plasma cells, it is important to know how these T cells are affected by short-chain fatty acids produced by subgingival plaque. The purpose of this study is to examine the effects of extracellular metabolites from periodontopathic bacteria on the proliferation and cytokine production of mouse splenic cells as a potential mechanism of imbalance among host-microbial interactions. A low-molecular-weight, heat-stable agent present in the two-day culture filtrate of Porphyromonas gingivalis, Prevotella loescheii, and Fusobacterium nucleatum significantly depressed Con A- and LPS- induced cell proliferation. To determine whether short-chain fatty acids present in the filtrate could account for the depression, we tested extracted volatile and non-volatile fatty acids for their effects on mitogenic activity. The volatile fatty acids extracted from immunosuppressive supernatants greatly inhibited T- and B- cell proliferation. Among these volatile fatty acids, butyric, propionic, valeric, and isovaleric acids impaired cell proliferation dose-dependently. From gas-liquid chromatographic analysis data, it is suggested that immuno-inhibitory activities in culture filtrates are mainly attributable to butyric and isovaleric acids in P. gingivalis, to propionic, butyric, and isovaleric acids in P. loescheii, and to butyric acid in F. nucleatum. Furthermore, these fatty acids significantly depressed interleukin 2 (IL-2), IL-4, IL-5, IL-6, and IL-10 production by Con A-stimulated splenic-T cells dose-dependently.(ABSTRACT TRUNCATED AT 250 WORDS)

Background: Peripheral lung lesions are increasing in numbers. Endoscopic diagnosis is essential for the prevention of unnecessary operations. Conventional diagnostic procedures have limitations in availability and results. Objectives: Endobronchial ultrasonography (EBUS) was investigated as a means to guide transbronchial lung biopsy, to reduce the discomfort during the procedure and to improve diagnostic accuracy. Methods: In 50 cases, we performed transbronchial lung biopsy combined with EBUS and fluoroscopic guidance. The results were compared to 42 controls assessed by fluoroscopy only. Results: In 38 cases (76%), EBUS could describe the peripheral lesion (33 from inside, including 9 cases with difficulties in fluoroscopic observation, and 5 from an adjacent bronchus, indicating the correct location of the lesion). If successfully placed inside, a change in the patient’s position was not required, which helped to reduce patient discomfort. Lung cancer was diagnosed in 24 patients and benign disease in 25 patients; in 1 case diagnosis remained unknown. When the EBUS probe could be introduced inside the lesion, the sensitivity for cancer diagnosis and specificity for cancer exclusion were 100%, respectively (15/15, 18/18). Compared to the controls in whom the biopsy site was determined by fluoroscopy only, the sensitivity tended to be superior by EBUS, although it did not reach statistical significance (p = 0.06). However, specificity and accuracy were statistically significant (both p = 0.02). Conclusions: When the lesion can be correctly described by EBUS from inside the lesion, EBUS is useful to guide transbronchial lung biopsy, can contribute to a reduction in patient discomfort and improves the accuracy of diagnosis. Additional navigation tools to increase correct positioning of the EBUS probe are desirable.

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A new strain of Serratia marcescens UCP1459 isolated from a semi-arid soil produced the natural red pigment prodigiosin, characterized by an uncommon pyrrolylpyrromethane skeleton. Prodigiosin is a promising drug due to its reported antifungal, immunosuppressive and anti-proliferative activities. The objective of this work was to indentify a suitable medium to simultaneously enhance S. marcescens growth and pigment production using renewable resources obtained from industrial wastes. S. marcescens produced the highest level of prodigiosin (49.5 g/L) at 48 h of cultivation using 6% “manipueira” (cassava wastewater) supplemented with mannitol (2%) at pH 7 and 28 °C. Carbohydrates in “manipueira” and mannitol play a role in the enhanced cell growth and prodigiosin production. The purified pigment extracted from the biomass was analyzed by mass spectrophotometry and showed the expected molecular weight of 324 Da corresponding to prodigiosin. In conclusion, we have successfully designed a new, economically feasible medium supporting enhanced S. marcescens growth and a high yield production of prodigiosin.

The purpose of this study was to examine the effect of butyric acid, an extracellular metabolite from periodontopathic bacteria, on apoptosis induction in murine thymocytes, splenic T cells, and human Jurkat T cells. Butyric acid significantly suppressed T-cell viability in both a concentration-and time-dependent fashion. The results of DNA fragmentation assay indicated that butyric acid rapidly induced apoptosis in thymocytes (with 1.25 mM butyric acid and 6 h after treatment) and in splenic T cells and Jurkat cells (with 2.5 mM butyric acid and 16 h after treatment). Incubation of thymocytes or Jurkat cells with 5 mM butyric acid for 21 h resulted in the typical ladder pattern of DNA fragmentation. Furthermore, Jurkat cells treated with 5 mM butyric acid showed the characteristic pattern of apoptotic cells such as chromatin condensation and hypodiploid nuclei. Experiments with fractionated subpopulations of splenic T cells revealed that DNA fragmentation was predominantly observed in CD4 ؉ T cells. Butyric acid-induced apoptosis of thymocytes was decreased by the protein kinase inhibitors H7 and staurosporine. These inhibitors were less effective with similarly treated splenic T cells and Jurkat cells. These data suggest that butyric acid, one of the volatile fatty acids produced by periodontopathic bacteria and one that easily penetrates the oral mucosa, can modulate the immunoregulatory cell population in periodontal tissue by inducing T-cell death through apoptosis.