ABSTRACT
Objective:To investigate the effect of 1 064-nm Q-switched Nd:YAG laser at different energy settings on cell viability, protease activity and structures of Malassezia furfur. Methods:Cultured standard strains of Malassezia furfur were divided into several groups to be irradiated with 1 064-nm Q-switched Nd:YAG laser at different energies of 0 (control group) , 500, 600, 700, 800 and 900 mJ, respectively. Then, fungal suspensions in the above groups were inoculated onto the Leeming & Notman medium separately. After 7-day culture, the diameter and number of colonies were measured to evaluate the fungal cell viability, the protease activity was measured by using the whole-milk plate medium, and the ultrastructure of Malassezia furfur in each group was observed by transmission electron microscopy. One-way analysis of variance was used for comparisons among multiple groups, least significant difference- t test for multiple comparisons, and Pearson correlation analysis for analyzing correlations of laser energy with colony diameter, number and protease activity. Results:The colony diameter and number both significantly differed among the control group, 500-, 600-, 700-, 800- and 900-mJ groups (colony diameter: 4.05 ± 0.69, 3.76 ± 0.51, 3.28 ± 0.41, 3.09 ± 0.72, 2.54 ± 0.64 and 2.43 ± 0.41 mm, respectively; colony number: 4 787 ± 597, 4 287 ± 761, 1 879 ± 275, 1 082 ± 248 and 209 ± 42, 72 ± 31 colony-forming units, respectively; F = 14.83, 231.85, respectively, both P < 0.05) , and were significantly decreased in the 600-, 700-, 800- and 900-mJ groups compared with the control group (all P < 0.05) . The laser energy was negatively correlated with the colony diameter and number ( r = -0.67, -0.91, respectively, both P < 0.05) . The protease activity significantly differed among the control group, 500-, 700- and 900-mJ groups ( F = 346.60, P < 0.05) , and was significantly lower in the 700- and 900-mJ groups than in the control group (both P < 0.05) . There was a negative correlation between the laser energy and protease activity ( r = -0.94, P < 0.05) . Transmission electron microscopy showed intact fungal structures in the control group, relatively intact fungal structures in the 500-mJ group, and obviously damaged fungal structures in the 600- to 900-mJ groups, and the greater the laser energy, the more severely the fungal structures were damaged. Conclusion:The 1 064-nm Q-switched Nd:YAG laser could affect the cell viability of and protease activity in Malassezia furfur, and damage its structures.
ABSTRACT
Objective To investigate skin rash characteristics in patients with dengue fever, and to explore factors associated with the occurrence of skin rashes in dengue fever. Methods Skin rashes were observed in 127 hospitalized patients with dengue fever. Clinical and laboratory data were collected from these patients. Statistical analysis was carried out by using a two-sample t-test and chi-square test with the SPSS16.0 software. Results Out of the 127 inpatients, 88 (69.29%)had skin rashes, which usually developed within 5-7 (average, 5.06 ± 2.50)days after fever onset. Among the 88 patients, 37(42.05%)developed skin rashes during fever, while 51(57.95%)after the drop of body temperature. Moreover, 48 (54.55%) patients complained of itching, while 39 (44.32%) never felt itch, and 1 complained of a tingling sensation all over the body. The type of skin rashes was various. Congestive erythema and macules were observed on both palms in 26 (29.55%)patients, and might be the characteristic skin presentation of dengue fever. Skin rashes usually began in both lower extremities, whereas the order of their subsidence was unclear. There was a significant difference in blood platelet (PLT) count as well as alanine transaminase and aspartate transaminase levels between patients with skin rashes and those without(all P=0.00). However, no significant difference was observed in the count of leukocytes, neutrophils or PLT, or the levels of alanine transaminase or aspartate transaminase between patients with hemorrhagic rashes and those with nonhemorrhagic rashes or between patients with itching and those without (all P>0.05). Conclusions Dengue fever has various skin rashes, and congestive erythema and macules on both palms may be the distinctive presentation of dengue fever.