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1.
Org Lett ; 23(6): 2342-2346, 2021 03 19.
Article in English | MEDLINE | ID: mdl-33683897

ABSTRACT

Rifamycins have been clinically utilized against mycobacterial infections for more than 50 years; however, their biosynthesis has not been fully elucidated. Here, on the basis of in vivo gene deletions, in vitro enzyme assays, isotope labeling, and site-directed mutations, we found that a flavin-dependent monooxygenase encoded by a rifamycin biosynthetic gene cluster, Rif-Orf17, not only converted the naphthoquinone chromophore of rifamycin S into benzo-γ-pyrone but also linearized rifamycin SV through phenolic hydroxylation. Both oxidation routes lead to inactivation of rifamycins.


Subject(s)
Flavins/chemistry , Mixed Function Oxygenases/chemistry , Rifamycins/chemistry , Anti-Bacterial Agents/biosynthesis , Anti-Bacterial Agents/chemistry , Flavins/metabolism , Molecular Structure , Multigene Family , Oxidation-Reduction , Rifamycins/metabolism
2.
Front Microbiol ; 11: 971, 2020.
Article in English | MEDLINE | ID: mdl-32582048

ABSTRACT

Rifamycin derivatives, such as rifampicin, have potent antibiotic activity and have long been used in the clinic as mainstay components for the treatment of tuberculosis, leprosy, and AIDS-associated mycobacterial infections. However, the extensive usage of these antibiotics has resulted in the rapid development of bacterial resistance. The resistance mechanisms mainly include mutations of the rifamycin target RNA polymerase of bacteria and enzymatic modifications of rifamycin antibiotics. One modification is the recently characterized rifamycin degradation catalyzed by Rox enzymes, which belong to the widely occurring flavin monooxygenases. Intriguingly, our recent sequence analysis revealed the rifamycin producers also encode Rox homologs that are not yet characterized. In this work, we expanded the study of the Rox-catalyzed rifamycin degradation. We first showed that the Rox proteins from rifamycin producers have the enzymatic rifamycin SV-degrading activity. Then we used the structurally diverse rifamycin compounds rifampicin and 16-demethylrifamycin W to probe the substrate scope and found that they each have a slightly different substrate scope. Finally, we demonstrated that Rox proteins can also catalyze the transformation of 16-demethylsalinisporamycin to 16-demethylsaliniketal A. Since 16-demethylsalinisporamycin and 16-demethylsaliniketal A are the counterpart analogs of salinisporamycin and saliniketal A, our biochemical findings not only uncover a previously uncharacterized self-resistance mechanism in the rifamycin producers, but also bridge the gap between the biosynthesis of the potential antitumor compound saliniketal A.

3.
Med Sci Law ; 58(1): 58-61, 2018 Jan.
Article in English | MEDLINE | ID: mdl-29363384

ABSTRACT

Dental injuries, especially of the incisors, caused by punches in violent criminal attacks could be seen in daily forensic casework involving the identification of injuries to a living body. Sometimes, when there is neither circumstantial evidence nor information about the surrounding circumstances, it is difficult to discern the cause of these injuries and the manner in which they were inflicted. As an example of clinical forensic medicine, we present the case of a 58-year-old woman whose teeth were injured when fighting with her son-in-law over household affairs with no witnesses present. The two parties had conflicting stories about the cause of the woman's injury. The woman claimed that her teeth were lost while she was being beaten by her son-in-law, and the man argued that the damage to his mother-in-law's teeth was self-inflicted when she bit his fingers. The police attending the crime called for a forensic examination. Forensic practitioners analysed the mechanism of the tooth loss using multi-slice spiral computed tomography (MSCT) and imaging reconstruction technology. Local alveolar bone (medial alveolar) fracture and a small area of alveolar bone loss were found on MSCT. Thus, forensic medical experts speculated that the woman's lower central and lateral incisors were lost as a result of a violent attack and were not self-inflicted. Finally, forensic practitioners helped police in avoiding a miscarriage of justice and wrongful conviction.


Subject(s)
Alveolar Bone Loss/diagnostic imaging , Alveolar Process/diagnostic imaging , Alveolar Process/injuries , Jaw Fractures/diagnostic imaging , Physical Abuse , Alveolar Bone Loss/etiology , Female , Forensic Medicine , Humans , Jaw Fractures/etiology , Middle Aged , Tomography, Spiral Computed
4.
J Ophthalmol ; 2016: 4087096, 2016.
Article in English | MEDLINE | ID: mdl-27688906

ABSTRACT

UNLABELLED: Objective. To explore the potential effects of methanol and its metabolite, formic acid, on rat retina function. Methods. Sprague-Dawley rats were divided into 3- and 7-day groups and a control. Experimental groups were given methanol and the control group were provided saline by gavage. Retinal function of each group was assessed by electroretinogram. Concentrations of methanol and formic acid were detected by GC/HS and HPLC, respectively. Results. The a and b amplitudes of methanol treated groups decreased and latent periods delayed in scotopic and photopic ERG recordings. The summed amplitudes of oscillatory potentials (OPs) of groups B and C decreased and the elapsed time delayed. The amplitudes of OS1, OS3, OS4, and OS5 of group B and OS3, OS4, and OS5 of group C decreased compared with the control group. The IPI1 of group B and IPI1-4 of group C were broader compared with the control group and the IPI1-4 and ET of group B were broader than group C. CONCLUSIONS: Both of scotopic and photopic retinal functions were impaired by methanol poisoning, and impairment was more serious in the 7-day than in the 3-day group. OPs, especially later OPs and IPI2, were more sensitive to methanol intoxication than other eletroretinogram subcomponents.

5.
Fa Yi Xue Za Zhi ; 31(2): 105-8, 2015 Apr.
Article in Chinese | MEDLINE | ID: mdl-26245086

ABSTRACT

OBJECTIV: e To find the correlation between real best corrected visual acuity (BCVA) and testing results of microperimetry and visual evoked potential (VEP) and to explore a new method in recording BCVA in macular disease. METHODS: Sixty-two patients with macular disease (macular disease group, 62 eyes) and eighteen healthy volunteers (control group, 36 eyes) had BCVA, microperimetry and VEP recorded. RESULTS: (1) By microperimetry, the values of retinal mean sensitivity and fixation percentage in macular disease group were lower than that in control group. The bicurve ellipse area in macular disease group was higher than that in control group. By VEP, P100 amplitude under 0.5 cpd and 2 cpd in macular disease group were significantly higher than that in control group and the latency was prolonged (P < 0.05). (2) In macular disease group, BCVA had significant positive correlation with retinal mean sensitivity, bicurve ellipse area, macular central 2 degrees and 4 degrees fixation percentage, respectively (P < 0.05). There was a significant correlation between retinal mean sensitivity and P100 amplitude (P < 0.05). (3) Multiple linear regression equation was y = 0.053 x1+0.008 x3+3.897 (y was BCVA, while x1 was retinal mean sensitivity and x3 was P100 amplitude under 2 cpd). CONCLUSION: Combined use of microperimetry and VEP is useful in the assessment of BCVA in macular disease.


Subject(s)
Evoked Potentials, Visual/physiology , Macula Lutea/physiopathology , Visual Field Tests/methods , Case-Control Studies , Eye , Humans , Retina , Retinal Diseases/pathology , Tomography, Optical Coherence , Visual Acuity/physiology
6.
Fa Yi Xue Za Zhi ; 31(1): 20-2, 27, 2015 Feb.
Article in Chinese | MEDLINE | ID: mdl-26058128

ABSTRACT

OBJECTIVE: To compare the correlation between contrast vision (LV) and sweep visual evoked potential acuity (SVEP-A) among people with emmetropia, mild myopia, and moderate myopia. METHODS: The CV and SVEP-A were tested individually in 96 eyes from healthy young volunteers, including 37 eyes of emmetropia, 27 eyes of mild myopia, and 32 eyes of moderate myopia. The statistic analysis was done by ANOVA analysis and rank sum test. RESULTS: (1) With the decrease of contrast, CV and SVEP-A decreased in every group. (2) At 100% contrast, the difference of CV between emmetropia and mild myopia had statistical significance (P<0.05). At 100%, 25% and 10% contrast, the difference of CV between emmetropia and moderate myopia had statistical significance (P<0.05). (3) In the same group, the difference of 100% and 25% contrast had statistical significance (P < 0.05). So was between 100% and 10% contrast. (4) At 100% and 10% contrast, the difference of CV and SVEP-A had statistical significance (P < 0.05). CONCLUSION: The CV of myopia relates to many factors including ametropia and fundus lesions. The correction of ametropia is important to the values of CV and SVEP-A.


Subject(s)
Evoked Potentials, Visual/physiology , Myopia/physiopathology , Visual Acuity/physiology , Eye , Fundus Oculi , Humans , Neurologic Examination , Severity of Illness Index , Vision Tests/instrumentation
7.
Fa Yi Xue Za Zhi ; 30(4): 261-3, 2014 Aug.
Article in Chinese | MEDLINE | ID: mdl-25434087

ABSTRACT

OBJECTIVE: To compare the agreement of anterior chamber angle examination by ultrasound biomicroscope (UBM), slit lamp optical coherence tomography (SL-OCT), and gonioscopy in angle recession and angle closure. METHODS: The anterior chamber angle was measured with UBM, SL-OCT and gonioscopy in turns for temporal, nasal, superior and inferior quadrant in the same dark room. The results were compared with the agreement of the three methods in angle recession and angle closure by χ2 test and Kappa test. RESULTS: There were no statistically significant differences of the three methods in testing angle closure and angle recession (P>0.05). The consistency of UBM and gonioscopy was better (Kappa value of 0.882) than that of SL-OCT and gonioscopy (Kappa value of 0.624). CONCLUSION: When testing angle recession, UBM is better than SL-OCT with gonioscopy as the standard. When testing angle closure, UBM, SL-OCT and gonioscopy have good agreement.


Subject(s)
Glaucoma, Angle-Closure , Gonioscopy , Microscopy, Acoustic , Tomography, Optical Coherence , Anterior Chamber , Humans , Intraocular Pressure , Slit Lamp
8.
Fa Yi Xue Za Zhi ; 30(3): 178-80, 2014 Jun.
Article in Chinese | MEDLINE | ID: mdl-25272870

ABSTRACT

OBJECTIVE: To study the characters of oscillatory potentials (OPs) of electroretinogram (ERG) after methanol intoxication in rats. METHOD: The SD rat models of methanol intoxication were established and divided into control group, 3-day intoxication group, 7-day intoxication group. The changes of OPs of ERG were recorded in a dark room. RESULTS: The total amplitudes of 3-day and 7-day intoxication groups decreased approximately 50% compared with that of the control group, while the schedule delayed approximately 16% and 61%, respectively. CONCLUSION: The characters of methanol intoxication in rats included delay in schedule and decline in the total amplitude of OPs.


Subject(s)
Electroretinography , Methanol/poisoning , Retina/physiopathology , Animals , Rats
9.
Fa Yi Xue Za Zhi ; 30(6): 470-3, 2014 Dec.
Article in Chinese | MEDLINE | ID: mdl-25816583

ABSTRACT

alphaB-crystallin is the structural protein of vertebrate lens, which is widely expressed in non-lens tissue. As one of the heat shock protein family members, alphaB-crystallin possesses biological properties of molecular chaperones and anti-apoptotic effects. Multi-factor injuries, such as retinopathy, inflammation and nervous system diseases, have a closely relationship with alphaB-crystallin. This paper reviews the research progress of the expression and mechanism of alphaB-crystallin in retina and extraocular tissues and organs.


Subject(s)
Gene Expression Regulation, Developmental , Heat-Shock Proteins/metabolism , alpha-Crystallin B Chain/metabolism , Crystallins , Humans , Lens, Crystalline , Retina
10.
Fa Yi Xue Za Zhi ; 29(4): 286-9, 294, 2013 Aug.
Article in Chinese | MEDLINE | ID: mdl-24350547

ABSTRACT

Multifocal visual electrophysiology, consisting of multifocal electroretinography (mfERG) and multifocal visual evoked potential (mfVEP), can objectively evaluate retina function and retina-cortical conduction pathway status by stimulating many local retinal regions and obtaining each local response simultaneously. Having many advantages such as short testing time and high sensitivity, it has been widely used in clinical ophthalmology, especially in the diagnosis of retinal disease and glaucoma. It is a new objective technique in clinical forensic medicine involving visual function evaluation of ocular trauma in particular. This article summarizes the way of stimulation, the position of electrodes, the way of analysis, the visual function evaluation of mfERG and mfVEP, and discussed the value of multifocal visual electrophysiology in forensic medicine.


Subject(s)
Electroretinography/methods , Evoked Potentials, Visual/physiology , Eye Injuries/diagnosis , Retina/physiology , Vision, Ocular/physiology , Electrodes , Electrophysiology , Eye Injuries/physiopathology , Forensic Medicine/methods , Glaucoma/diagnosis , Glaucoma/physiopathology , Humans , Image Processing, Computer-Assisted , Retina/physiopathology , Retinal Diseases/diagnosis , Retinal Diseases/physiopathology , Visual Acuity/physiology , Visual Fields/physiology
11.
Fa Yi Xue Za Zhi ; 29(2): 96-8, 2013 Apr.
Article in Chinese | MEDLINE | ID: mdl-23930500

ABSTRACT

OBJECTIVE: To study the correlativity between the projected visual chart vision ("projector vision" in this paper) and the measured values of contrast vision, and to explore the application of contrast vision in identifying visual impairment after eye injury in the clinical forensic medicine. METHODS: One hundred and twenty nine eyes of seventy-nine young volunteers were collected for examination both of projector vision and contrast vision. In the examination of contrast vision, the contrast of optotypes were set to 100%, 25% and 10%, respectively. The correlativity of both collected experimental data were statistically analyzed. RESULTS: Projector vision was consistent with 100% contrast vision. There was a close and positive correlation between the contrast of optotypes and measured vision values. Under the same contrast of optotypes, projector vision presented a linear correlation with the average value of contrast vision. CONCLUSION: There is a close correlation between projector vision and contrast vision. The contrast vision can be applied to judicial identification in the clinical forensic medicine.


Subject(s)
Contrast Sensitivity , Vision Tests , Visual Acuity , Adult , Eye Injuries/diagnosis , Female , Humans , Male , Middle Aged , Young Adult
12.
Fa Yi Xue Za Zhi ; 28(1): 24-7, 2012 Feb.
Article in Chinese | MEDLINE | ID: mdl-22435333

ABSTRACT

OBJECTIVE: To study the application value of contrast vision in identifying the malingering decreased vision in the practice of clinical forensic medicine. METHODS: Thirty-one young and middle aged volunteers were selected and divided randomly into group 1 (16 persons with 32 eyes) and group 2 (15 persons with 30 eyes). The optotype contrast was 100%, 25%, 10% and 5%, respectively. The contrast vision of group 1 was tested. The contrast vision of group 2 was tested as follows: (1) the volunteers cooperated without inspector's interference; (2) the volunteers cooperated under inspector's interference; (3) the volunteers disguised decreased vision without inspector's interference; (4) the volunteers disguised decreased vision under inspector's interference. The data was then analyzed by statistics. RESULTS: There was a close correlation between contrast vision and contrast. As the contrast decreased, the vision acuity also decreased. The contrast vision curve of former two methods showed a good reproducibility while the contrast vision curve of latter two methods had a bad reproducibility. CONCLUSION: The repetition of contrast curve with or without inspector's interference can be used to discriminate malingering vision. The acquired contrast curves can be provided to the court as direct evidence and can help enhance the verification conclusion.


Subject(s)
Malingering/diagnosis , Vision Tests/methods , Vision, Low/diagnosis , Visual Acuity , Adult , Contrast Sensitivity/physiology , Diagnosis, Differential , Female , Humans , Male , Malingering/psychology , Reproducibility of Results , Sensitivity and Specificity , Severity of Illness Index , Vision Tests/statistics & numerical data , Vision, Binocular , Vision, Low/psychology , Young Adult
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