The first case report of infective endocarditis caused by Gemella taiwanensis.

Gemella is a facultative anaerobic Gram-positive coccus and a rare cause of infective endocarditis (IE). Gram staining may eventually misidentify the organism, which tends to easily decolorize and manifest as either Gram-negative or Gram-variable. Commercial biochemical tests are often used to identify Gemella, but the methods they employ sometimes lack accuracy. A 52-year-old woman was diagnosed with Gemella taiwanensis IE after initial identification of the pathogen as Gemella haemolysans using biochemical tests combined with matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). She was treated successfully with penicillin, gentamicin, and mitral valve replacement. To our knowledge, this is the first case of IE confirmed by 16S rRNA gene and groEL sequencing to have been caused by G. taiwanensis. The accurate diagnosis of rare or difficult-to-identify pathogens is a major challenge for clinical microbiological laboratories. The concurrent use of molecular methods could lead to the recognition of new or different pathogens.

[Contact investigation using QuantiFERON-TB Gold test to evaluate TB exposure in 61 subjects in a hospital setting--(2) Change in QuantiFERON response during one year after exposure].

UNLABELLED: OBJECTIVES & SUBJECTS: The change in IGRA (interferon-gamma release assay, with QuantiFERON-TB Gold, QFT) responses was followed up for one year in a group of contacts of healthcare workers who had been exposed to tuberculosis (TB) infection for a relatively short period in a hospital. The observation was made of a total of 59 close contacts of the index case, where 16 showed positive QFT-conversion and 7 showed the intermediate response ranging 0.1 to 0.35 IU/mL. Three of the conversion cases developed active TB. RESULTS: 67% of the QFT conversions occurred within 2 months of exposure and the others between 2 to 9 months. Those having converted later than 2 months after the exposure showed generally weaker QFT responses than the earlier converters. In response to the treatment to converters (either to latent TB infection or to active TB), 80% of the cases reversed to negative or intermediate. The geometric means of the response values for ESAT-6 and CFP-10 also showed significant decline over the treatment time. DISCUSSIONS: The time profile of responses in the intermediate responders revealed an obviously distinct pattern from that of the negative responders with the values remaining uniformly at very low level throughout, which suggests that this group includes somehow exceptional responders either with or without infection.

[Contact investigation using QuantiFERON-TB Gold test to evaluate TB exposure in 61 subjects in a hospital setting--(1) Outline of the outbreak and its clinical picture].

The index case was a patient who was admitted to a general hospital and treated with pulsed corticosteroid therapy; her breathing was assisted by a respirator. Soon she developed tuberculosis (TB) and died. Immediately after her death, QuantiFERON-TB Gold (QFT) test was conducted in healthcare workers who were in close contact with the index case. From the results of the test, all the healthworkers except 1 were TB negative. However, the QFT test repeated in the healthworkers after 8 weeks was positive in 18.6%. Subsequently, 5 healthworkers, including a doctor, nurses, and radiology technicians, developed TB. Bacterial isolates from 3 of them showed restriction fragment length polymorphism (RFLP) patterns similar to that of the index case. These 3 secondary TB cases included one healthworker who was in contact with the index case for less than 5 min, another whose QFT was negative (or "doubtful" according to the Japanese criterion of the QFT), and a third who was TB positive for QFT test but declined treatment for latent TB infection (LTBI). No other healthworkers or hospitalized patients developed TB. These healthcare workers with TB were further assessed using the QFT test at 6, 9, and 12 months after initial exposure, which showed an additional 4 positive reactors and 4 "doubtful" reactors who were indicated for LTBI treatment. Among these subjects, 7 were those who showed TB positive results 6 months after initial contact. Discussions were made on TB prevention in hospital settings including contact investigations the staff with special reference to application of the QFT test.

Note: in vivo pH imaging system using luminescent indicator and color camera.

Microscopic in vivo pH imaging system is developed that can capture the luminescent- and color-imaging. The former gives a quantitative measurement of a pH distribution in vivo. The latter captures the structural information that can be overlaid to the pH distribution for correlating the structure of a specimen and its pH distribution. By using a digital color camera, a luminescent image as well as a color image is obtained. The system uses HPTS (8-hydroxypyrene-1,3,6-trisulfonate) as a luminescent pH indicator for the luminescent imaging. Filter units are mounted in the microscope, which extract two luminescent images for using the excitation-ratio method. A ratio of the two images is converted to a pH distribution through a priori pH calibration. An application of the system to epidermal cells of Lactuca Sativa L is shown.

Ethylene stimulates endoreduplication but inhibits cytokinesis in cucumber hypocotyl epidermis.

The effects of ethylene on cell division are generally considered inhibitory. In this study, we demonstrate that transient ethylene exposure, while suppressing cytokinesis, stimulates DNA synthesis. We monitored DNA synthesis and cytokinesis in the epidermis of cucumber (Cucumis sativus) hypocotyls, an organ whose post-germination development involves strictly limited cell division. During exposure to ethylene, DNA synthesis, assessed by the incorporation of the thymidine homolog 5-bromo-2'-deoxyuridine, was detected in 20% of the epidermal cells, whereas DNA synthesis was nearly undetectable in normal air. Cytofluorometric analysis of nuclei in affected cells showed an up to 8-fold increase in DNA content. During this time, new cell plate formation was not detected. However, shortly after ethylene was removed, DNA content was rapidly restored to 2C (diploid) levels in all cells, and new cell plate formation dramatically increased. These results demonstrate that ethylene promotes DNA synthesis and its endoreduplication but inhibits cytokinesis, thereby maintaining some cells in G2 phase.

Transient exposure to ethylene stimulates cell division and alters the fate and polarity of hypocotyl epidermal cells.

After transient exposure to the gaseous hormone ethylene, dark-grown cucumber (Cucumis sativus) hypocotyls developed unusual features. Upon ethylene's removal, the developing epidermis showed significant increases in cell division rates, producing an abundance of guard cells and trichomes. These responses to ethylene depended on the stage of development at the time of ethylene exposure. In the upper region of the hypocotyl, where cells were least differentiated at the onset of ethylene treatment, complex, multicellular protuberances formed. Further down the hypocotyl, where stomata and trichomes were beginning to develop at the onset of ethylene exposure, an increase in the number of stomata and trichomes was observed. Stomatal complexes developing after the ethylene treatment had a significant increase in the number of stomatal subsidiary cells and the number of cells per trichome increased. Analysis of division patterns in stomatal complexes indicated that exposure to ethylene either suspended or altered cell fate. Ethylene also altered cell division polarity, resulting in aberrant stomatal complexes and branched trichomes. To our knowledge, the results of this study demonstrate for the first time that transient treatment with physiological concentrations of ethylene can alter cell fate and increase the propensity of cells to divide.