Guangdong Landau Biotechnology Co.

Guangzhou, China

Guangdong Landau Biotechnology Co.

Guangzhou, China

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Chen L.,Nanjing Southeast University | Fan X.,Nanjing Southeast University | Jin G.,Nanjing Southeast University | Wan X.,Nanjing Southeast University | And 4 more authors.
Journal of Biomedical Nanotechnology | Year: 2014

Transplantation of bone marrow stromal cells (BMSCs) or Schwann cells (SCs) can facilitate axonal regeneration in nerve injuries. The aim of this study was to assess the effect of BMSCs and SCs transplantation on a rat with traumatic brain injury (TBI) and cellular migration in brain, and investigate whether combined BMSCs and SCs transplantations have more advantages than BMSCs transplantation alone. BMSCs were cultured in vitro and then labeled with SPIO. The labeled and unlabeled cells were assayed by MTT inspection to compare the effect of SPIO on growth activity of rat's BMSCs. Sciatic nerve was taken of the rat and striped off epineurium to obtain SCs by carrying out cell culture using mixed enzyme digestion. The SCs were identified by immunofluorescence labeling for S-100 protein and cellular activities were analyzed by MTT growth curves. Improved Feeney method was adopted to make a rat TBI model. In total, 50 male Sprague Dawley (SD) rats weighing 200-250 g were randomly divided into 5 groups: Groups A-E (n = 10 for each group). Injections of nutrient and stereotactic transplantation of BMSCs labeled with SPIO and stereotactic transplantation of SCs and BMSCs labeled with SPIO were administered in these groups 48 hours after TBI modeling. Neurological severity scores (NSS) were implemented at the 3 day, 1 week, 2 week and 4 week, respectively, after transplantation and 7.0T MRI scanning was done to observe migration situation of transplanted cells. After completion of MRI inspection at 4 weeks post transplantation, all rats were sacrificed and their brain tissue sections taken and assayed by HE staining and prussian blue staining. Numerous BMSCs were successfully labeled with SPIO. The labeling efficiency was more than 90%. There was no obvious difference between cellular proliferation of BMSCs labeled and unlabeled with SPIO at different time points. SCs were cultured in vitro and SCs S-100 detected as positive. MRI results show that T2WI was expressed in low signal area and migrated towards injury side after BMSCs labeled with SPIO were transplanted into brain. The combined transplantation had a quicker migration speed than single transplantation. NSS result shows that the combined transplantation group had a low score than single transplantation group after 2 weeks. In conclusion, BMSCs labeled with SPIO can be transplanted into brain and can be used in 7.0T MRI tracing in vivo. Compared to single transplantation, the combined transplantation of BMSCs and SCs has a quicker cellular migration and a better prognosis. Copyright © 2014 American Scientific Publishers All rights reserved.


Chen L.,Nanjing Southeast University | Qiu R.,Nanjing Southeast University | Xu Q.,Guangdong Landau Biotechnology Co.
Journal of Nanoscience and Nanotechnology | Year: 2014

This paper reviews the recent studies and development of mesenchymal stem cell (MSCs) therapy for neurodegenerative diseases. MSCs transplantation, a promising therapy, can promote functional recovery by producing trophic factors that induce survival and regeneration of host neurons in animal models and patients with neurodegenerative diseases. In this review, we introduce briefly the potential benefits of MSCs. Finally, the possibility of clinical application in neurodegenerative diseases is also discussed. Copyright © 2014 American Scientific Publishers All rights reserved.


Chen L.,Nanjing Southeast University | Qiu R.,Nanjing Southeast University | Xu Q.,Guangdong Landau Biotechnology Co.
Journal of Nanoscience and Nanotechnology | Year: 2014

This paper reviews the recent studies and development of stem cell therapy for ischemic stroke. Stem cells can differentiate into several types of mature cells, including neurons and glial cells. Stem cell transplantation, a promising therapy, can be able to facilitate functional recovery both in animal models and stroke patients. In this review, we introduce briefly the different types of endogenous stem cells and the transplantation of exogenous stem cells; in addition, we discuss the timing, dosage, route, and tracing of stem cell therapy for ischemic stroke in details. Finally, the clinical challenge and application of stem cells in future are also discussed. Copyright © 2014 American Scientific Publishers All rights reserved.


Yang J.,Xiamen University | Chen L.,Nanjing Southeast University | Chitkara N.,NASA | Xu Q.,Guangdong Landau Biotechnology Co.
Neurology India | Year: 2014

Background: Given the importance of intracranial stenosis as a cause of recurrent ischemic stroke and the lack of evidence supporting a clear choice for prevention of recurrent ischemic events, a computer simulation model for prognostic prediction could be used to improve decision making. Aims: The aim of the following study is to compare the long-term effect of aspirin, clopidogrel and clopidogrel plus aspirin for prevention of recurrent stroke due to atherosclerotic intracranial artery stenosis. Setting and Design: The cohort consisted of 206 patients from 2006 to 2011. Materials and Methods: A two-state Markov model was used to predict the prognosis of patients with stroke or transient ischemic attack (TIA) caused by angiographically verified 50-99% stenosis of a major intracranial artery to receive aspirin, clopidogrel, or dual therapy. Statistical Analysis: Two tests were used: Pearson Chi-square test or Fisher's exact test (for percentages) and Kruskal Wallis test (for rank order data). Results: In the 10-year Markov cohort analysis, 36.24% of patients who were treated with clopidogrel plus aspirin developed to recurrent stroke while the probability for patients in the aspirin group and clopidogrel group was 42.60% and 48.39% respectively. Patients with clopidogrel plus aspirin had the highest quality-adjusted life years, followed by aspirin and clopidogrel. Conclusion: To prevent recurrent stroke in patients with intracranial artery stenosis, especially in those patients with a history of TIA or coronary artery disease, medical therapy with clopidogrel plus aspirin should be considered in preference to aspirin alone.


Chen X.,Sun Yat Sen University | Dang G.,Sun Yat Sen University | Dang C.,Sun Yat Sen University | Liu G.,Sun Yat Sen University | And 4 more authors.
Restorative Neurology and Neuroscience | Year: 2015

Purpose: We aimed to develop a nonhuman primate (NHP) stroke model for studies of secondary lesions in remote areas and to characterize its behavioral and neuroimaging features. Methods: Monkeys were either subjected to middle cerebral artery occlusion (MCAO) distal to the M1 branch (n = 17) or sham operation (n = 7). Neurological assessment and magnetic resonance imaging (MRI) were performed before and 1 week after operation. Results: After MCAO, six monkeys showed occlusion of the distal M1 segment and infarcts predominantly in the cortical and subcortical regions, without hippocampal and thalamic involvement. They had obvious neurological deficits. The other 11 monkeys showed blockage of the main trunk of the MCA, with infarcts extending into the hippocampus and thalamus, but no substantia nigra involvement. Their infarct volume were larger and neurological deficits were more severe than those after distal M1 occlusion. All sham-operated monkeys displayed normal behavior; however, MRI revealed small infarcts in three animals. Conclusions: MCAO or even sham operations might cause cerebral infarction in NHPs. Therefore, neurological assessment should be combined with MRI for screening candidate stroke models. Our model is suitable for studying secondary damage in remote regions, including the thalamus, hippocampus, and substantia nigra, after stroke. © 2015 - IOS Press and the authors. All rights reserved.


Xu Q.,General Hospital of PLA | Xu Q.,Military General Hospital of Beijing PLA | Xu Q.,Southern Medical University | Xu Q.,Guangdong Landau Biotechnology Co. | And 6 more authors.
Cellular and Molecular Neurobiology | Year: 2011

Tracking of ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles-labeled embryonic stem cells, neural stem cells, or adult mesenchymal stem cells in vitro and in vivo by using magnetic resonance (MR) imaging have been reported. However, whether the transdifferentiated cells can be effectively labeled by USPIO has not yet been investigated. The requirement for nerve donor material evokes additional morbidity and inability to generate a sufficiently large number of cells in a short time to hamper the clinic application of Schwann cells (SCs) transplantation. These limitations may be avoided if SCs can be generated from clinically accessible sources, such as bone marrow and umbilical cord. However, a reliable means of inducing the selective differentiation of human mesenchymal stromal cells isolated from the umbilical cord (HUMSCs) into SCs in vitro has not yet been established. In this study, we induce HUMSCs into Schwann-like cells in terms of morphology, phenotype, and function by an improved protocol basing on our previous studies. Furthermore, HUMSCs-derived SCs are labeled efficiently in vitro with ultrasmall superparamagnetic iron oxide contrast agent (USPIO) Sinerem and poly-l-lysine (PLL) without affecting morphology, cell cycle, proliferation, and differentiation ability of the labeled cells between the concentration of 200 to 800 μg/ml. Importantly, when grafted into the intact cerebral cortex and striatum, the survival and migration of these Sinerem-labeled cells were observed using MRI. Our study suggest the effective concentration field for Sinerem use in tracking transdifferentiated HUMSCs, and Sinerem labeling transdifferentiated HUMSCs is feasible, efficient, and safe for MRI tracing following grafting into nervous system. © 2010 Springer Science+Business Media, LLC.


Xiang R.,South China University of Technology | Zhang H.,South China University of Technology | Deng Q.,South China University of Technology | Yue R.,South China University of Technology | And 9 more authors.
Immunogenetics | Year: 2013

High-frequency alleles and/or co-occurring human leukocyte antigen alleles across loci appear to be more important than individual alleles as markers of disease risk and have clinical value as biomarkers for targeted screening or the development of new disease therapies. To better elucidate the major histocompatibility complex (MHC) background and to facilitate the experimental use of cynomolgus macaques, Mafa-DPA1, Mafa-DQA1, Mafa-DRA, and Mafa-DOA alleles were characterized, and their combinations were investigated in 30 Vietnamese macaques by gene cloning and sequencing. A total of 26 Mafa-DPA1, 18 Mafa-DQA1, 9 Mafa-DRA, and 15 Mafa-DOA alleles, including 7 high-frequency alleles, were identified in this study, respectively. In addition, 15 Mafa-DQA1, 17 Mafa-DPA1, 15 Mafa-DOA, and 2 Mafa-DRA alleles represented novel sequences that had not been documented in earlier studies. Our results also showed that the Vietnamese macaques might be valuable because no less than 30 % of the test animals possessed Mafa-DRA*01:02:01 (90 %), -DQA1*26:01:03 (37 %), -DOA*01:02:07 (34 %), and -DQA1*01:03:03 (30 %). We previously reported that the combinations of MHC class II alleles, including the combination of DOA*01:02:07-DPA1*02:09 and DOA*01:02:07- DQA1*01:03:03, were detected in 17 and 14 % of the animals, respectively. Interestingly, more than two Mafa-DQA1 and Mafa-DPA1 alleles were detected in one animal in this study, which suggested that they might be caused by a chromosomal duplication. If our findings can be validated by other studies, it will further enrich the number of known Mafa-DPA1 and Mafa-DQA1 polymorphisms. Our results identified the co-occurring MHC alleles across loci in a cohort of Vietnamese cynomolgus macaques, which emphasized the value of this species as a model for biomedical research. © 2013 Springer-Verlag Berlin Heidelberg.


Wang S.,Xinxiang Medical University | Wang S.,Chinese Academy of Sciences | Wang S.,Harvard University | Wang S.,Guangdong Landau Biotechnology Inc. Ltd. | And 5 more authors.
PLoS ONE | Year: 2015

Melatonin plays a protective role in type 2 diabetes (T2D) through regulation of glucose metabolism. Whether transcutaneous vagus nerve stimulation (taVNS) is antidiabetic and whether a modulated melatonin production is involved in the antidiabetic mechanism of taVNS is unknown. In this study, once daily 30min noninvasive taVNS was administered in Zucker diabetic fatty (ZDF, fa/fa) and Zucker lean (ZL, +/fa) littermates under anesthesia for 5 consecutive weeks. The acute and chronic influences of taVNS on the secretion of melatonin were studied as well as the effects of taVNS on blood glucose metabolism. We found that naïve ZDF rats develop hyperglycemia naturally with age. Each taVNS session would trigger a tidal secretion of melatonin both during and after the taVNS procedure and induce an acute two-phase glycemic change, a steep increase followed by a gradual decrease. Once daily taVNS sessions eventually reduced the glucose concentration to a normal level in seven days and effectively maintained the normal glycemic and plasma glycosylated hemoglobin (HbAlc) levels when applied for five consecutive weeks. These beneficial effects of taVNS also exist in pinealectomized rats, which otherwise would show overt and continuous hyperglycemia, hyperinsulinemia, and high HbAlc levels. We concluded that multiple taVNS sessions are antidiabetic in T2D through triggering of tidal secretion of melatonin. This finding may have potential importance in developing new approaches to the treatment of T2D, which is highly prevalent, incurable with any current approaches, and very costly to the world. © 2015 Wang et al.


Wan Y.L.,Guangdong Landau Biotechnology Co.
Dong wu xue yan jiu = Zoological research / "Dong wu xue yan jiu" bian ji wei yuan hui bian ji | Year: 2011

To screen spontaneous diabetic mellitus and explore methods for its rapid identification, the basal and inferred levels of blood glucose of 440 overweight, middle- and old-aged cynomolgus monkeys were analyzed. Diagnostic diabetes was further validated by the oral glucose tolerance test (OGTT) and urine glucose. The average level of blood glucose of these cynomolgus monkeys was (3.88±0.98) mmol/L, which was lower than the level for suspected diabetes (5.0 mmol/L). Of them, 56 (12.72%) monkeys were identified with levels of blood glucose greater than 5.0 mmol/L and diagnosed as the diabetic subjects. This population showed impaired glucose tolerance using the OGTT and 39 of the 56 (69.23%) had glucose positive urine. The methods for screening diabetic mellitus used in this study were simple, quick, and limited the harm to animals. However, the incidence of diabetes was higher in these tested monkeys than in the regular human population in China (9.7%), suggesting that these methods are useful for screening diabetic disease in a large population but not suitable for all cynomolgus monkeys.


PubMed | Guangdong Landau Biotechnology Co.
Type: Journal Article | Journal: Dong wu xue yan jiu = Zoological research | Year: 2011

To screen spontaneous diabetic mellitus and explore methods for its rapid identification, the basal and inferred levels of blood glucose of 440 overweight, middle- and old-aged cynomolgus monkeys were analyzed. Diagnostic diabetes was further validated by the oral glucose tolerance test (OGTT) and urine glucose. The average level of blood glucose of these cynomolgus monkeys was (3.880.98) mmol/L, which was lower than the level for suspected diabetes (5.0 mmol/L). Of them, 56 (12.72%) monkeys were identified with levels of blood glucose greater than 5.0 mmol/L and diagnosed as the diabetic subjects. This population showed impaired glucose tolerance using the OGTT and 39 of the 56 (69.23%) had glucose positive urine. The methods for screening diabetic mellitus used in this study were simple, quick, and limited the harm to animals. However, the incidence of diabetes was higher in these tested monkeys than in the regular human population in China (9.7%), suggesting that these methods are useful for screening diabetic disease in a large population but not suitable for all cynomolgus monkeys.

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