Homeobox Gene Six3 is Required for the Differentiation of D2-Type Medium Spiny Neurons / 神经科学通报·英文版

Medium spiny neurons (MSNs) in the striatum, which can be divided into D1 and D2 MSNs, originate from the lateral ganglionic eminence (LGE). Previously, we reported that Six3 is a downstream target of Sp8/Sp9 in the transcriptional regulatory cascade of D2 MSN development and that conditionally knocking out Six3 leads to a severe loss of D2 MSNs. Here, we showed that Six3 mainly functions in D2 MSN precursor cells and gradually loses its function as D2 MSNs mature. Conditional deletion of Six3 had little effect on cell proliferation but blocked the differentiation of D2 MSN precursor cells. In addition, conditional overexpression of Six3 promoted the differentiation of precursor cells in the LGE. We measured an increase of apoptosis in the postnatal striatum of conditional Six3-knockout mice. This suggests that, in the absence of Six3, abnormally differentiated D2 MSNs are eliminated by programmed cell death. These results further identify Six3 as an important regulatory element during D2 MSN differentiation.

MR conventional sagittal-axial plane and coronal iterative decomposition of water and fat with echo asymmetry and least-squares estimation technique in diagnosis of extraforaminal lumbar disc herniation / 中国医学影像技术

Objective To compare the diagnostic value of MR conventional sagittal-axial plane and coronal iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) technique in diagnosis of extraforaminal lumbar disc herniation (ELDH).Methods Totally 32 patients with ELDH confirmed by surgery underwent preoperative MR sagittal-axial plane and coronal IDEAL scanning.Disc herniation,nerve involvement,nerve angle,nerve deep impression,nerve thinning or truncation,nerve adhesion unsmooth and nerve swelling were analyzed between the two methods.Results Disc herniation,nerve involvement and number of reduction or disappearance of surrounding fat had no statistically significant differences between the two methods (all P＞0.05),while nerve angle,nerve deep impression,nerve thinning or truncation,nerve adhesion unsmooth and nerve swelling were significantly different between the two methods (all P＜0.05).Surgical operation confirmed that 32 patients with nerve compression were consistent with findings by IDEAL.Conclusion MR sagittal-axial plane and coronal IDEAL both can be used to diagnose ELDH,but their display ability of nerve compression is different.Coronal IDEAL is superior to conventional sagittal-axial plane and is an effective imaging method,being able to display nerve compression more intuitively,clearly and comprehensively.

The role of spo0A gene in growth and sporulation of Clostridium difficile / 中国感染与化疗杂志

Objective To investigate the role of spo0A gene in growth and sporulation of Clostridium difficile clinical isolates. Methods ClosTron gene knock-out system was used to knock out the spo0A gene of C. difficile strain C25. Bacterial growth curve was plotted by measuring D600 with spectrophotometer in different phases of bacterial growth. Malachite green staining technique was used to count the number of vegetative cells and spores under optical microscope. The sporulation rate was calculated. Results The spo0A mutant and its C25 parental strain showed similar patterns of growth. However, after knock-out of spo0A gene, an asporogenous phenotype was built, while the parental strain could produce spores as usual.Conclusions The spo0A gene plays a key role in sporulation but not growth of C. difficile strain.

BOLD-fMRI study on the basic activity of the brain in major disorder depression and their first-degree relatives / 实用放射学杂志

Objective To study the characteristics and differences of the amplitude of low-frequency fluctuation (ALFF) and the fractional ALFF (fALFF) of the major disorder depression (MDD) and their first-degree relatives in the resting state by functional magnetic resonance imaging (fMRI),to understand the early brain function in patients with MDD.Methods 3.0T fMRI in the resting state was performed in 10 patients with MDD (the depression group),10 first-degree relatives of MDD (the first-degree relatives group) and 10 healthy volunteers (the control group).A statistics analysis of ALFF and fALFF were performed subsequently.Results The ALFF and fALFF values measured in left cerebellum, left precuneus and left medial prefrontal cortex of MDD group were significantly lower than those of the first-degree relatives group (P<0.05).The ALFF values measured in right posterior cingulate cortex and right superior parietal lobule of MDD group were significantly lower than those of the first-degree relatives group (P<0.05).The ALFF and fALFF values measured in left cerebellum, left precuneus and left superior parietal lobule of MDD group were significantly lower than those of the control group (P<0.05).The ALFF values measured in right cingulate cortex and medial prefrontal cortex of MDD group were significantly lower than those of the control group (P<0.05).There was no significance difference found in ALFF values between the first-degree relatives group and the control group,the fALFF values measured in left superior parietallobule of the first-degree relatives group were significantly lower than those of the control group (P<0.05).Conclusion As the widespread ALFF, fALFF abnormalities of brain in MDD and first-degree relatives of MDD,a hypothesis can be get that these abnormal brain region may be associated with cognitive network disorders and emotional distress in MDD.

Establishment and evaluation of hamster model of Clostridium difficile-associat-ed diarrhea / 中国感染与化疗杂志

Objective To explore a method for establishing the hamster model of Clostridium difficile-associated diarrhea (CDAD)and the indicators for its evaluation.Methods Clindamycin was administered to hamsters subcutaneously (day 1),and 24 h later infected with C.difficile clinical isolates KH1 (ribotype 027,106-108 CFU/mL)or SH9 (ribotype 001 ,108-1010 CFU/mL)by gavage.Animals were observed for CDAD symptoms such as diarrhea,weight loss and death.At the end of ob-servation period (day 7 or death),the cecum was collected from each animal for histological evaluation of inflammation.Results Following a single dose of 100 mg/kg clindamycin subcutaneously,all the animals challenged with KH1 (108 CFU/mL)devel-oped diarrhea and then died within 5 days.All the hamsters challenged with SH9 (1010 CFU/mL)developed diarrhea as well but only 66.7% died at the end of observation period.Among other groups,only one or none developed diarrhea and then died. The symptoms of hamsters with diarrhea included loose stool,wet tail and weight loss.On histological examination,conges-tion,hemorrhage and neutrophil infiltration of the mucosa were observed in the hamsters died of CDAD.Conclusions We have successfully established a hamster CDAD model that allows for future investigations.

Three-dimensional reconstruction and digitized visualization of the sacrum of women of Uygur and Han nationalities in Xinjiang / 南方医科大学学报

<p><b>OBJECTIVE</b>To construct digitized three-dimensional models of the sacrum of women of Uygur and Han nationalities in Xinjiang and assess their value in anatomical studies.</p><p><b>METHODS</b>Ninety Uygur women and 90 Han women of child-bearing age in Xinjiang were recruited. Digitized three-dimensional reconstruction was used to construct the sacrum models for morphological study and measurement of the physiological indices.</p><p><b>RESULTS</b>The sacral forms of Han women were consistent with the standard anatomical descriptions. Of the Uygur women, 57 (63.3%) showed a standard type of the sacrum, 6 (6.7%) had 4 pairs of sacral foramens, 9 (10%) had 5 pairs of sacral foramens, and 18 (20%) had sacrococcygeal joint abnormalities. There were significant differences in sacral morphologies between the two nationalities (P<0.05). The depths of the sacrum foramen and sacral hiatus were significantly greater in Uyghur women than in Han women (P<0.05). Only a minor proportion of the cases had nonstandard sacral types, found only in Uygur women.</p><p><b>CONCLUSIONS</b>Uygur and Han women of child-bearing age in Xinjiang have morphological and anatomical differences of the sacrum, which should be considered in clinical practice.</p>

Residual dentin thickness in first premolars after root canal preparation / 华西口腔医学杂志

<p><b>OBJECTIVE</b>The residual dentin thickness of first premolars were measured by anatomical methods before and after post preparation, the data from which can help clinicians to choose proper sizes of peeso drill.</p><p><b>METHODS</b>30 first maxillary premolars and 30 first mandibular premolars were collected. Walls of 4 mm short of the apex were respectively measured before and after post preparation with peeso drills number 1-3.</p><p><b>RESULTS</b>The measurement results of all indexes assumed a normal distribution. For two-canal first maxillary premolars and single-canal first mandibular premolars, the average residual mesial and distal thickness of root walls 4 mm short of the apex were less than 1 mm after post preparation by number 3 peeso drill. The buccal root had nonsignificant differences (P>0.05). The palatine root and the first mandibular premolars had significant differences (P<0.05). For single-canal first maxillary premolars, the average residual mesial and distal thickness were less than 1 mm after post preparation by number 2 peeso drill. The distal wall had significant differences (P<0.05).</p><p><b>CONCLUSION</b>In post preparation, for the buccal root of two-canal maxillary premolars, the maximum size of peeso drill was number 3, and for the palatine root and first mandibular premolars, the size was number 2, and for single-canal maxillary first premolars, the size was number 1.</p>

3-D Image of Near-infrared Fluorescent Probe in Tissue-like Solution / 航天医学与医学工程

Objective To develop the fluorescence molecular imaging system and obtain the 3D images of near-infrared fluorescent probe in tissue-like solution.Methods Weak optical signals were acquired with hypothermal cooled CCD camera.The system captured the fluorescent images of different projections at rotating the tissue phantom.The photon propagation in tissue followed the diffusion approximation theory.The 3D image of probe was calculated with a fast reconstruction algorithm based on finite element approach.Results The imaging system could obtain the full-angle dense raw dataset.The reconstruction algorithm had capacity to recover the position and contour of the fluorescent target included in diffusive medium.Conclusion The results from phantom experiments are promising and show the potentials to act as a platform for in vivo fluorescence tomography.

A Reconstruction Algorithm for Fluorescence Molecular Tomography Based on the Total Least-Squares Rule and the Normalized Conjugate Gradient Method / 航天医学与医学工程

Objective To find an efficient and practical reconstruction algorithm for the fluorescence molecular tomography basing on total leastsquares rule as well as the normalized conjugate gradient method.Methods The finite element method was used to get the weighting matrix from the forward diffusion model.For the inverse reconstruction problem,the total least-squares rule was employed.The normalized conjugate gradient method was applied to find the fluorochrome information in the objective area.Results The simulation experiments showed that images reconstructed by the total least-squares rule were more accurate than those reconstructed by the least-squares rule under the same circumstances when noise existed.The presented algorithm could also give consistent results when the initial guesses varied in a wide range.Conclusion The algorithm presented in this paper offers a practical and efficient reconstruction for the fluorescence molecular tomography.