PubMed Health⌕ Search

Biomedical subjects

Jian Mao

Publications and source records attributed to Jian Mao.

9 recordsLinked to original sources
PubMed2006

[Etiology of laryngeal stridor in neonates: analysis of 16 cases].

OBJECTIVE: To reduce misdiagnosis and explore etiology of laryngeal stridor in neonates. METHODS: Sixteen neonates with laryngeal stridor were reviewed. All the patients were examined with CT scan for larynx and lungs and some were examined with laryngoscopy. Laboratory examination and chromosome analysis were also done in all or some patients. RESULTS: All the 16 neonates were diagnosed before admission as congenital simple laryngeal stridor in other hospitals. Of the 16 neonates with laryngeal stridor, 5 (31%) had thyroglossal ductal cyst, 1 (6%) neonate with cri du chat (5p(-)) syndrome, 2 (13%) neonates with Pierre-Robin syndrome and the rest 8 (50%) were suspected of congenital simple laryngeal stridor. CONCLUSION: Neonates with laryngeal stridor are easily misdiagnosed; neonatal thyroglossal duct cyst is one of common causes. The diagnosis for a congenital simple laryngeal stridor should be carefully made excluding the possibility of related diseases. The authors recommend that laryngoscopy and CT scan for larynx should be performed in the neonates with laryngeal stridor.

Diagnostic Errors↗
PubMed2006

[Evaluation of MRI in nasopharyngeal carcinoma with cavernous sinus infiltration].

OBJECTIVE: To investigate the incidence, MRI characteristics and invasion route of nasopharyngeal carcinoma (NPC) infiltrating the cavernous sinus. METHODS: The data of 141 patients with histologically proven NPC collected from May 2003 to June 2004 were reviewed. All patients were examined by 1.5-tesla superconducting MR unit to evaluate the tumor extent. MR FSE technique was used for T1 WI and T2WI images in the axial plane, followed by FSPGR fat-suppressed gadolinium-enhancement for T1WI images in the axial and coronal sections. All MR images were interpreted and evaluated by two diagnostic radiologists, paying particular attention to the nasopharynx and cavernous sinus infiltration. RESULTS: MR imaging showed infiltration of 49 cavernous sinuses in 39 patients (27.7%). The most common MRI features were enlargement of cavernous sinus with unconventional enhancement (22/49, 44.9%), even with formation of mass inside the sinus (9/49, 18.4%). The other MRI image features were local or diffuse dura mater thickening of cavernous sinus and presence of obscure structure as intra-sinus blurs and hazies inside. The most common infiltration route is through the foramen ovale (18/49, 36.7%), or through both the foramen ovale and foramen lacerum (6/49, 12.2%). CONCLUSION: In NPC patients, MRI invasion is characteristically and clearly shown as changes in the cavernous sinus. Possession of this information is crucial for giving correct treatment. The main infiltrtion route is through foramen ovale.

Adolescent↗
PubMed2005

From The Cover: A role for Arabidopsis cryptochromes and COP1 in the regulation of stomatal opening.

Cryptochromes (CRY) are blue light photoreceptors that mediate various light-induced responses in plants and animals. Arabidopsis CRY (CRY1 and CRY2) functions through negatively regulating constitutive photomorphogenic (COP) 1, a repressor of photomorphogenesis. Water evaporation and photosynthesis are regulated by the stomatal pores in plants, which are closed in darkness but open in response to blue light. There is evidence only for the phototropin blue light receptors (PHOT1 and PHOT2) in mediating blue light regulation of stomatal opening. Here, we report a previously uncharacterized role for Arabidopsis CRY and COP1 in the regulation of stomatal opening. Stomata of the cry1 cry2 double mutant showed reduced blue light response, whereas those of the CRY1-overexpressing plants showed hypersensitive response to blue light. In addition, stomata of the phot1 phot2 double mutant responded to blue light, but those of the cry1 cry2 phot1 phot2 quadruple mutant hardly responded. Strikingly, stomata of the cop1 mutant were constitutively open in darkness and stomata of the cry1 cry2 cop1 and phot1 phot2 cop1 triple mutants were open as wide as those of the cop1 single mutant under blue light. These results indicate that CRY functions additively with PHOT in mediating blue light-induced stomatal opening and that COP1 is a repressor of stomatal opening and likely acts downstream of CRY and PHOT signaling pathways.

Arabidopsis↗
PubMed2005

CT perfusion at early stage of hepatic diffuse disease.

AIM: To determine the validity of the non-invasive method of CT perfusion (CTP) in rat model of hepatic diffuse disease. METHODS: Twenty-eight Wistar rats were divided into two groups. Liver diffuse lesions were induced by diethylnitrosamine in 14 rats of test group. Rats in control group were bred with pure water. From the 1st to 12th wk after the test group was intervened, both groups were studied every week with CTP. CTP parameters of liver parenchyma in different periods and pathologic changes in two groups were compared and analyzed. RESULTS: The process of hepatic diffuse lesions in test groups was classified into three stages or periods according to the pathologic alterations, namely hepatitis, hepatic fibrosis, and cirrhosis. During this period, hepatic artery flow (HAF) of control group declined slightly, mean transit time (MTT), blood flow (BF) and volume (BV) increased, but there were no significant differences between different periods. In test group, HAF tended to increase gradually, MTT prolonged obviously, BV and BF decreased at the same time. The results of statistical analysis revealed that the difference in the HAF ratio of test group to control group was significant. The ratio of BV and BF in test group to control group in stage of hepatitis and hepatic cirrhosis, hepatic fibrosis and early stage of hepatic cirrhosis was significantly different, but there was no significant difference between hepatitis and hepatic fibrosis. The main pathological changes in stage of hepatitis were swelling of hepatic cells, while sinusoid capillarization and deposition of collagen aggravated gradually in the extravascular Disse's spaces in stage of fibrosis and early stage of cirrhosis. CONCLUSION: The technique could reflect some early changes of hepatic blood perfusion in rat with liver diffuse disease and is valuable for their early diagnosis.

Animals↗
PubMed2005

Magnetic resonance diffusion-weighted imaging in the diagnosis of diffuse liver diseases in rats.

BACKGROUND: The diagnosis of diffuse hepatic lesions in early stage is a tough task at any time for clinical conventional imaging. Magnetic resonance diffusion-weighted imaging (MR DWI) can detect the changes of tissue structure at molecular level. This study was designed to determine the value of DWI in the diagnosis of diffuse liver lesions in early stage. METHODS: Diffuse liver lesions were induced by diethylnitrosamine in 42 rats of test group. Fourteen rats in control group were fed with pure water. Dynamic changes of MR DWI were observed every week in both groups during the early stage of diffuse liver lesions (1 to 12 weeks after drug administration in the test group). Apparent diffusion coefficient (ADC) values of liver parenchyma in different stages and pathologic changes were analyzed. RESULTS: The process of diffuse hepatic lesions in the test group was classified into three stages according to pathological changes, namely hepatitis, hepatic fibrosis and cirrhosis. No obvious morphological changes were shown by conventional imaging in both groups during this stage. But MR DWI demonstrated heterogeneous signal changes in early stage of hepatic cirrhosis in the test group. No significant change of ADC values was found in the control group between different weeks (P > 0.05). The ADC values of the test group declined from the fifth week, and after the tenth week the ADC values were significantly different between the test and control groups at gradient factor (b) value 300 sec/mm(2) (P < 0.05). At b value 600 and 1000 sec/mm(2), significant difference was seen between the two groups from the sixth week onward. The range of ADC value of the groups was (1.7 - 0.9) +/- (0.40 - 0.04) mm(2)/sec (b = 600) and (1.38 - 0.75) +/- (0.07 - 0.35) mm(2)/sec (b = 1000), respectively. Dominant pathological changes included swelled hepatocytes within 1 to 4 weeks after the administration of diethylnitrosamine in the test group, hyperplasia of fibrous tissues in 5 - 8 weeks and formation of cirrhotic nodules in 9 - 12 weeks. CONCLUSIONS: MR functional DWI could detect diffuse liver lesions earlier than conventional morphological imaging. ADC value as a marker for early diagnosis of diffuse liver lesions could also be used to inspect changes of the lesions.

Animals↗
PubMed2005

N-terminal domain-mediated homodimerization is required for photoreceptor activity of Arabidopsis CRYPTOCHROME 1.

Cryptochromes (CRY) are blue light receptors that share sequence similarity with photolyases, flavoproteins that catalyze the repair of UV light-damaged DNA. Transgenic Arabidopsis thaliana seedlings expressing the C-terminal domains of the Arabidopsis CRY fused to beta-glucuronidase (GUS) display a constitutive photomorphogenic (COP) phenotype, indicating that the signaling mechanism of Arabidopsis CRY is mediated through the C-terminal domain. The role of the Arabidopsis CRY N-terminal photolyase-like domain in CRY action remains poorly understood. Here, we report the essential role of the Arabidopsis CRY1 N-terminal domain (CNT1) in the light activation of CRY1 photoreceptor activity. Yeast two-hybrid assay, in vitro binding, in vivo chemical cross-linking, gel filtration, and coimmunoprecipitation studies indicate that CRY1 homodimerizes in a light-independent manner. Mutagenesis and transgenic studies demonstrate that CNT1-mediated dimerization is required for light activation of the C-terminal domain of CRY1 (CCT1). Transgenic data and native gel electrophoresis studies suggest that multimerization of GUS is both responsible and required for mediating a COP phenotype on fusion to CCT1. These results indicate that the properties of the GUS multimer are analogous to those of the light-modified CNT1 dimer. Irradiation with blue light modifies the properties of the CNT1 dimer, resulting in a change in CCT1, activating CCT1, and eventually triggering the CRY1 signaling pathway.

Arabidopsis↗
PubMed2005

[Evaluation of early stage diffused liver lesions with MR functional diffusion-weighted imaging--an experimental study].

OBJECTIVE: To investigate the value of Diffusion-Weighted Imaging (DWI) in the diagnosis of early stage liver diffuse lesions. METHODS: Diethylnitrosamine (DEN) was used to induce liver lesions in rats. Sequential DWI studies were performed on the livers from 1 to 14 weeks after DEN was administered through drinking water. Comparing studies with a blank control group was set and pathohistological examinations of the livers were performed. RESULTS: No obvious routine MRI morphological change was found in either group during this period, but DWI demonstrated heterogeneous changes in the test group at the cirrhosis stage. There was no significant alteration of the apparent diffusion coefficient (ADC) value in the control group during this period (P > 0.05). The ADC values of the test group began to decline from the fifth week. Until the tenth week, the ADC value of the test group decreased drastically and when b = 300 s/mm2 statistic, the results showed an obvious difference between the two groups. There were also differences between the ADC values at the 10th, the 9th and the 1st weeks of the test group (P < 0.05). When b = 600 s/mm2 and 1000 s/mm2, significant differences were found after the sixth week between the two groups (P < 0.01). The main pathohistological liver change in the test group during the 1 to 4 week period after DEN was administered was swelling of hepatocytes; during the 5 to 8 week period it was fibrous tissues hyperplasia, and in the 9 to 14 week period it was cirrhotic nodule formation. CONCLUSION: MR functional DWI could detect liver diffuse lesions earlier than conventional MR imaging. Measurement of ADC value may be of use in early diagnosis of liver diffuse diseases and for monitoring the changes of the lesions.

Animals↗
PubMed2003

Hypoxia-ischemic encephalopathy in full-term neonate: correlation proton MR spectroscopy with MR imaging.

INTRODUCTION: To evaluate 1H Magnetic Resonance Spectroscopy (1HMRS) in the diagnosis of hypoxia-ischemic encephalopathy (HIE) of full-term neonates correlated with Magnetic Resonance Imaging (MRI). MATERIALS AND METHODS: Thirty-eight cases of full-term neonates diagnosed as HIE clinically were selected to perform MRI and 1HMRS examination. The ages ranged from 7 to 17 days, with median age of 8.2 days. In which, 26 cases were followed up and/or MRI reexamined at 6 months of age or later. Eight healthy neonates, with no evidence of birth asphyxia, also underwent 1HMRS for comparison. SE sequences were used for routine MR examination; point resolved spectroscopy sequence was required for 1HMRS. The metabolites in the spectra includes: N-acetylaspartate (NAA), choline compounds (CHO), creatine compounds (CR), myo-inositol (MI), lactate (LAC), glutamate and glutamine (Glu-Gln). RESULTS: The peaks of NAA were fall in two cases; the peaks of LAC, which were elevated, appeared as typical double-peaks appearance in 26 cases; the peaks of Glu-Gln, which were also elevated, appeared as zigzag appearance in nine cases. The peaks of CR were decreased in 11 cases, while those of MI were increased in seven cases. Mild type of lesions was present on MRI in 12 cases whose LAC/CR ratio lower than 0.5; mild and moderate types of lesions were present in 15 cases whose LAC/CR ratio between 0.5 and 1.5. Whereas, nine cases of severe lesions and two cases of moderate lesions were present on MRI in 11 cases whose LAC/CR ratio greater than 1.5. Twenty-six of 38 cases were followed up and/or MRI reexamined after 6 months, in which, sequelae were present in 12 cases. Among them, eight cases of sequelae in nine cases whose LAC/CR ratio greater than 1.5 were present (account for 88.89%). CONCLUSION: 1HMRS plays an important role to diagnose and predict outcome of HIE.

Apgar Score↗