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1.
Ther Drug Monit ; 44(3): 377-383, 2022 06 01.
Article in English | MEDLINE | ID: mdl-35094001

ABSTRACT

BACKGROUND: The clinical guidelines suggest that the dosing of cyclosporine (CsA), during combination therapy with paritaprevir/ritonavir-ombitasvir and dasabuvir (PrOD), would be only one-fifth of the pre-PrOD total daily dose to be administered once daily. However, this dosing may not be applicable to all patients depending on their clinical condition. This study focuses on the pharmacokinetic dynamics of PrOD with CsA in Asian organ transplant recipients with severe liver fibrosis or cirrhosis who undergo concurrent treatment with PrOD treatment and CsA. The efficacy and safety of PrOD treatment was also evaluated. METHODS: Data from 7 patients obtained between January 2017 and September 2017 were retrospectively analyzed. Determinations of the blood concentrations of CsA were made, whether used as a single treatment or in combination therapy with PrOD. RESULTS: The combination regimen compared with CsA administered alone resulted in a 4.53-fold and 5.52-fold increase in the area under the concentration-time curve from time 0-12 hours (AUC0-12 h) of CsA on days 1 and 15, respectively. In addition, the maximal concentration, time to maximum concentration, and terminal phase elimination half-life (t1/2) of CsA were increased during the combined treatment of PrOD and CsA. The authors proposed reducing the CsA dosage during PrOD treatment to one-seventh of that of the pre-PrOD treatment of the total daily dose to maintain target CsA levels. All patients achieved sustained virologic responses at week 12. There were no episodes of serious adverse events or graft rejections observed. CONCLUSIONS: Although the combination with PrOD significantly affects the pharmacokinetics of CsA, it is effective and safe with regular monitoring of the CsA blood concentrations and appropriate CsA dose adjustment.


Subject(s)
Hepatitis C , Macrocyclic Compounds , Organ Transplantation , 2-Naphthylamine , Anilides/therapeutic use , Antiviral Agents/adverse effects , Carbamates , Cyclopropanes , Cyclosporine/pharmacology , Cyclosporine/therapeutic use , Drug Interactions , Drug Therapy, Combination , Hepacivirus , Hepatitis C/drug therapy , Humans , Lactams, Macrocyclic , Liver Cirrhosis/drug therapy , Macrocyclic Compounds/therapeutic use , Proline/analogs & derivatives , Retrospective Studies , Ribavirin/therapeutic use , Ritonavir , Sulfonamides , Uracil/analogs & derivatives , Valine
2.
Phytother Res ; 31(8): 1119-1127, 2017 Aug.
Article in English | MEDLINE | ID: mdl-28504367

ABSTRACT

The autophagy-lysosome pathway (ALP) is a primary means by which damaged organelles and long-lived proteins are removed from cells and their components recycled. Impairment of the ALP has been found to be linked to the pathogenesis of Parkinson's disease (PD), a chronic neurodegenerative disorder characterized by the accumulation of protein aggregates and loss of dopaminergic neurons in the midbrain. In recent years, some active compounds derived from plants have been found to regulate the ALP and to exert neuroprotective effects in experimental models of PD, raising the possibility that autophagy enhancement may be an effective therapeutic strategy in PD treatment. In this review, we summarize recent findings of natural products that enhance ALP and thereby protect against PD. Research articles were retrieved from PubMed using relevant keywords in combination. Papers related to the topic were identified, and then the reliability of the experiments was assessed in terms of methodology. The results suggest that targeting the ALP with natural products is a promising strategy for PD treatment. However, risk of bias exists in some studies due to the defective methodology. Rigorous experimental design following the guidelines of autophagy assays, molecular target identification and in vivo efficacy evaluation is critical for the development of ALP enhancers for PD treatment in future studies. Copyright © 2017 John Wiley & Sons, Ltd.


Subject(s)
Autophagy/drug effects , Biological Products/pharmacology , Lysosomes/drug effects , Neuroprotective Agents/pharmacology , Parkinson Disease/drug therapy , Animals , Dopaminergic Neurons/pathology , Humans
3.
Int J Mol Sci ; 18(2)2017 Jan 28.
Article in English | MEDLINE | ID: mdl-28134846

ABSTRACT

Hippocampal neurogenesis plays a critical role in the formation of new neurons during learning and memory development. Attenuation of neurogenesis in the brain is one of the primary causes of dementia in Alzheimer's disease (AD), and, conversely, modulating the process of hippocampal neurogenesis benefit patients with AD. Traditional Chinese medicine (TCM), particularly herbal medicine, has been in use for thousands of years in Asia and many regions of the world for the treatment of cancer, cardiovascular diseases and neurodegenerative diseases. In this review, we summarize the role of neurotrophic factors, signal transducing factors, epigenetic modulators and neurotransmitters in neurogenesis, and we also discuss the functions of several Chinese herbs and their active molecules in activating multiple pathways involved in neurogenesis. TCM herbs target pathways such as Notch, Wnt, Sonic Hedgehog and receptor tyrosine kinase pathway, leading to activation of a signaling cascade that ultimately enhances the transcription of several important genes necessary for neurogenesis. Given these pathway activating effects, the use of TCM herbs could be an effective therapeutic strategy for the treatment of AD.


Subject(s)
Alzheimer Disease/drug therapy , Neurogenesis , Animals , Humans , Medicine, Chinese Traditional , Signal Transduction
4.
Chin Med ; 11: 44, 2016.
Article in English | MEDLINE | ID: mdl-27708694

ABSTRACT

BACKGROUND: Tianma-Gouteng-Yin (TGY), which is common Chinese medicine formulation consisting of 11 different herbs and being used in China for the treatment of Parkinson's disease, inflammatory conditions and cardiovascular diseases, was selected for full component analysis. The aim of this study was to quantitatively analyze the chemical profiles of ten commercial TGY samples and one sample produced in our laboratory. METHODS: Ultra-high performance liquid chromatography (UHPLC) coupled with quadrupole-tandem time-of-flight mass spectrometry (Q-TOF-MS) was used to analyze the non-saccharide small molecule components of the different TGY samples. The established method was validated in terms of its linearity, sensitivity, precision, accuracy and stability. High performance liquid chromatography coupled with evaporative light scattering detection (HPLC-ELSD) was also used to quantify three major saccharides (fructose, glucose and sucrose). RESULTS: The relative standard deviations for the precision, repeatability and stability of these compounds were less than 5 %, while the accuracy of the method was 95-105 %. Twenty-eight of the compounds found in TGY were successfully identified, with 20 being quantified. The macromolecules present in these samples were also identified using an ethanol precipitation method, representing 294.68-696.64 mg/g of the total material depending on the batch. Notably, the components identified using this method represented up to 78 % of the total weight of the TGY samples. CONCLUSIONS: The developed UHPLC/Q-TOF-MS and HPLC-ELSD methods successfully identified 28 of the complex compounds found in TGY.

5.
Autophagy ; 12(8): 1372-89, 2016 08 02.
Article in English | MEDLINE | ID: mdl-27172265

ABSTRACT

Autophagy dysfunction is a common feature in neurodegenerative disorders characterized by accumulation of toxic protein aggregates. Increasing evidence has demonstrated that activation of TFEB (transcription factor EB), a master regulator of autophagy and lysosomal biogenesis, can ameliorate neurotoxicity and rescue neurodegeneration in animal models. Currently known TFEB activators are mainly inhibitors of MTOR (mechanistic target of rapamycin [serine/threonine kinase]), which, as a master regulator of cell growth and metabolism, is involved in a wide range of biological functions. Thus, the identification of TFEB modulators acting without inhibiting the MTOR pathway would be preferred and probably less deleterious to cells. In this study, a synthesized curcumin derivative termed C1 is identified as a novel MTOR-independent activator of TFEB. Compound C1 specifically binds to TFEB at the N terminus and promotes TFEB nuclear translocation without inhibiting MTOR activity. By activating TFEB, C1 enhances autophagy and lysosome biogenesis in vitro and in vivo. Collectively, compound C1 is an orally effective activator of TFEB and is a potential therapeutic agent for the treatment of neurodegenerative diseases.


Subject(s)
Basic Helix-Loop-Helix Leucine Zipper Transcription Factors/metabolism , Curcumin/chemistry , TOR Serine-Threonine Kinases/metabolism , Animals , Autophagy , Brain/metabolism , Cell Nucleus/metabolism , HeLa Cells , Humans , Lysosomes/metabolism , Male , Mice , Neurodegenerative Diseases/metabolism , Phosphorylation , Protein Binding , Rats , Rats, Sprague-Dawley
6.
Pharmacoepidemiol Drug Saf ; 25(6): 661-7, 2016 06.
Article in English | MEDLINE | ID: mdl-26799240

ABSTRACT

PURPOSE: During the past two decades, many novel immunosuppressive drugs have been approved for transplant recipients. Trends in the use of maintenance immunosuppressants after liver transplantation in Asia are unclear. Thus, we aimed to analyze the prescription trends in maintenance immunosuppressive drugs among liver transplant recipients in Taiwan and compare the results with the trends reported from western countries. METHODS: We conducted a retrospective nationwide population-based study utilizing the National Health Insurance Research Database (NHIRD) to analyze the prescribing patterns of immunosuppressants used in Taiwanese liver transplant recipients from 2000 to 2009. RESULTS: A total of 1686 liver transplant patients and their prescriptions of immunosuppressants were analyzed. The 5-year survival rate of liver transplant recipients was 79.6%. In 2009, the major immunosuppressive therapy among liver transplant recipients was a dual-drug regimen with tacrolimus and mycophenolic acid (57.3%). Among the calcineurin inhibitors (CNI), the use of cyclosporine decreased from 58.9% to 12.5%, while the use of tacrolimus notably increased from 23.3% to 77.5%. The use of azathioprine decreased from 21.3% to 0.4%, while the use of mycophenolic acid increased from 56.1% to 76.5%. Among the mammalian target of rapamycin (mTOR) inhibitors, sirolimus was approved in 2002, and its use increased to 8.7% in 2009. In the first 3 months after liver transplantation, a total of 17 different regimens were used in 2009, compared with seven regimens in 2000. CONCLUSIONS: Although the CNI-based combination obviously remains the major regimen, our results reveal a trend toward individualized immunosuppressive regimens among Taiwanese liver transplant recipients. Copyright © 2016 John Wiley & Sons, Ltd.


Subject(s)
Calcineurin Inhibitors/administration & dosage , Immunosuppressive Agents/administration & dosage , Liver Transplantation/methods , Practice Patterns, Physicians'/statistics & numerical data , Adult , Databases, Factual , Drug Therapy, Combination , Female , Follow-Up Studies , Humans , Immunosuppressive Agents/pharmacology , Male , Middle Aged , Precision Medicine , Retrospective Studies , Survival Rate , Taiwan , Time Factors , Young Adult
7.
Sci Rep ; 5: 16862, 2015 Nov 18.
Article in English | MEDLINE | ID: mdl-26578166

ABSTRACT

Tianma Gouteng Yin (TGY) is a traditional Chinese medicine (TCM) decoction widely used to treat symptoms associated with typical Parkinson's disease (PD). In this study, the neuroprotective effects of water extract of TGY were tested on rotenone-intoxicated and human α-synuclein transgenic Drosophila PD models. In addition, the neuroprotective effect of TGY was also evaluated in the human dopaminergic neuroblastoma SH-SY5Y cell line treated with rotenone and the rotenone intoxicated hemi-parkinsonian rats. In rotenone-induced PD models, TGY improved survival rate, alleviated impaired locomotor function of Drosophila, mitigated the loss of dopaminergic neurons in hemi-parkinsonian rats and alleviated apoptotic cell death in SH-SY5Y cells; in α-synuclein transgenic Drosophila, TGY reduced the level of α-synuclein and prevented degeneration of dopaminergic neurons. Conclusively, TGY is neuroprotective in PD models both in vivo and in vitro.


Subject(s)
Dopaminergic Neurons/drug effects , Dopaminergic Neurons/metabolism , Drugs, Chinese Herbal/pharmacology , Medicine, Chinese Traditional , Neuroprotective Agents/pharmacology , Animals , Animals, Genetically Modified , Apoptosis/drug effects , Cell Count , Cell Line, Tumor , Chromatography, Liquid , Disease Models, Animal , Dopamine/metabolism , Drosophila , Drug Antagonism , Drugs, Chinese Herbal/administration & dosage , Drugs, Chinese Herbal/chemistry , Humans , Male , Mass Spectrometry , Neuroprotective Agents/administration & dosage , Neuroprotective Agents/chemistry , Parkinson Disease/drug therapy , Parkinson Disease/genetics , Parkinson Disease/metabolism , Parkinson Disease/pathology , Parkinson Disease/physiopathology , Rats , Rotenone/pharmacology , alpha-Synuclein/metabolism
8.
Pharmacoepidemiol Drug Saf ; 23(12): 1312-9, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25335855

ABSTRACT

PURPOSE: Significantly increasing heart transplantations have been performed in Taiwan in the past decades, but the trends of maintenance immunosuppression for heart transplant recipients have not been well known. In this study, we aimed to explore the trends of maintenance immunosuppressive therapy and common complications for heart transplant recipients. METHODS: We retrospectively analyzed ambulatory prescriptions in 488 heart transplant recipients for the period 2000-2009. Patient complications after heart transplantation were also identified. RESULTS: The annual number of new heart transplant recipients ranged from 18 to 68. The 5-year survival rate was 77.9%. The total number of regimens was 10 in 2000, and increased to 28 in 2009. Most prescriptions were immunosuppressive combinations (95.5%-89.5%). The majority of immunosuppressive regimens were a triple regimen: cyclosporine, mycophenolic acid and corticosteroid in 2009. Cyclosporine was a predominant calcineurin inhibitor with a decreasing trend from 73.9% to 59.1%, whereas the use of tacrolimus significantly increased from 11.9% to 38.4%. Mycophenolic acid was the most frequently used antimetabolite (60.1%-80.3%), while the use of azathioprine was reduced (21.6%-2.3%). From 2008, the launch of everolimus initiated a new era in the utilization of mammalian target of rapamycin inhibitors for maintenance immunosuppression. CONCLUSIONS: Cyclosporine remained the most frequently used calcineurin inhibitors, and tacrolimus increased gradually. Mycophenolic acid was the most popular antimetabolite rather than azathioprine. The rapidly increased everolimus combined regimen may change the patterns of maintenance immunosuppression. The increasing number of combination therapies indicates an active role of everolimus and a tendency of complex tailored individual therapies.


Subject(s)
Graft Rejection/drug therapy , Heart Transplantation , Immunosuppressive Agents/therapeutic use , Practice Patterns, Physicians'/trends , Transplant Recipients/statistics & numerical data , Drug Therapy, Combination , History, 21st Century , Humans , Retrospective Studies , Taiwan , Time Factors
9.
PLoS One ; 9(3): e92954, 2014.
Article in English | MEDLINE | ID: mdl-24671102

ABSTRACT

Huanglian-Jie-Du-Tang (HLJDT) is a famous traditional Chinese herbal formula that has been widely used clinically to treat cerebral ischemia. Recently, we found that berberine, a major alkaloid compound in HLJDT, reduced amyloid-ß (Aß) accumulation in an Alzheimer's disease (AD) mouse model. In this study, we compared the effects of HLJDT, four single component herbs of HLJDT (Rhizoma coptidis (RC), Radix scutellariae (RS), Cortex phellodendri (CP) and Fructus gardenia (FG)) and the modified formula of HLJDT (HLJDT-M, which is free of RS) on the regulatory processing of amyloid-ß precursor protein (APP) in an in vitro model of AD. Here we show that treatment with HLJDT-M and its components RC, CP, and the main compound berberine on N2a mouse neuroblastoma cells stably expressing human APP with the Swedish mutation (N2a-SwedAPP) significantly decreased the levels of full-length APP, phosphorylated APP at threonine 668, C-terminal fragments of APP, soluble APP (sAPP)-α and sAPPß-Swedish and reduced the generation of Aß peptide in the cell lysates of N2a-SwedAPP. HLJDT-M showed more significant APP- and Aß- reducing effects than berberine, RC or CP treatment alone. In contrast, HLJDT, its component RS and the main active compound of RS, baicalein, strongly increased the levels of all the metabolic products of APP in the cell lysates. The extract from FG, however, did not influence APP modulation. Interestingly, regular treatment of TgCRND8 APP transgenic mice with baicalein exacerbated the amyloid plaque burden, APP metabolism and Aß production. Taken together, these data provide convincing evidence that HLJDT and baicalein treatment can increase the amyloidogenic metabolism of APP which is at least partly responsible for the baicalein-mediated Aß plaque increase in the brains of TgCRND8 mice. On the other hand, HLJDT-M significantly decreased all the APP metabolic products including Aß. Further study of HLJDT-M for therapeutic use in treating AD is warranted.


Subject(s)
Alzheimer Disease/drug therapy , Amyloid beta-Protein Precursor/metabolism , Drugs, Chinese Herbal/therapeutic use , Protein Processing, Post-Translational , Alzheimer Disease/pathology , Animals , Berberine/pharmacology , Berberine/therapeutic use , Cell Survival/drug effects , Disease Models, Animal , Drugs, Chinese Herbal/chemistry , Drugs, Chinese Herbal/pharmacology , Flavanones/pharmacology , Flavanones/therapeutic use , Humans , Intracellular Space/metabolism , Mice, Transgenic , Mutation/genetics , Plaque, Amyloid/metabolism , Plaque, Amyloid/pathology , Protein Processing, Post-Translational/drug effects
10.
BMC Med Res Methodol ; 13: 148, 2013 Dec 05.
Article in English | MEDLINE | ID: mdl-24308700

ABSTRACT

BACKGROUND: Diagnostic problems in clinical trials are sometimes ordinal. For example, colon tumor staging was performed according to the TNM classification. However, clinical data are limited by markedly small sample sizes in some stage. METHODS: We propose a distribution-free test for detecting ordered alternatives in a completely randomized design. The new statistic is based on summing all correctly (ascending) ordered samples. RESULTS: The exact mean and variance of the null distribution are derived and it is shown that this distribution is asymptotically normal. Furthermore, we show using Monte Carlo simulation that the proposed test is a significant improvement over the Terpstra-Magel test. That is, power is decreased where the investigator falsely assumes an a priori ordering relationship. CONCLUSIONS: We conclude that these tests frequently detect an ordered trend when, in fact, one does not exist. However, the new test can reduce the error rate, at least not to the extent in which the Jonckheere-Terpstra test does.


Subject(s)
Data Interpretation, Statistical , Adenocarcinoma/classification , Adenocarcinoma/pathology , Algorithms , Colonic Neoplasms/classification , Colonic Neoplasms/pathology , Computer Simulation , Humans , Monte Carlo Method , Neoplasm Staging/methods , Statistics, Nonparametric
11.
Zhonghua Yu Fang Yi Xue Za Zhi ; 47(5): 455-8, 2013 May.
Article in Chinese | MEDLINE | ID: mdl-23958132

ABSTRACT

OBJECTIVE: To establish a method for determination of the epichlorohydrin in drinking water by isotope dilution gas chromatography-mass spectrometry (GC-MS). METHODS: The internal standard solution D5-epichlorohydrin was added in drinking water sample. The epichlorohydrin was firstly collected by active carbon, and the adsorbent was then centrifuged at 2739 × g for 10 min to remove water. Finally, the epichlorohydrin was desorbed by dipping the active carbon in 1.0 ml acetone for 1 h. The desorbed solution was tested by GC-MS and quantified with isotopic internal standards. The detection limit, precision and accuracy of the assay were evaluated. This method was adopted to detect the epichlorohydrin in drinking water for 25 batches in a city. RESULTS: The determination method of epichlorohydrin represented a good linear relationship in the range of 0.0645-3.8700 µg/L, the linear regression equation was Y = 2.828X + 4.91 × 10(-2) (r > 0.999). When the epichlorohydrin concentration were 0.0806, 0.3230 and 3.2300 µg/L, the relative standard deviations (RSD) were 7.9%, 4.7% and 3.1%, respectively. The average recoveries were from 95.7% to 98.7%. The limit of detection (LOD) was 0.015 µg/L, limit of quantification (LOQ) was 0.052 µg/L. The content of epichlorohydrin in the 25 cases of drinking water was under the limit of detection. CONCLUSION: The method is more simple than the national standard method, with high sensitivity, accuracy and good reproducibility, which is suitable for detection of the trace amounts of epichlorohydrin in drinking water.


Subject(s)
Drinking Water/analysis , Epichlorohydrin/analysis , Gas Chromatography-Mass Spectrometry/methods
12.
Invest Ophthalmol Vis Sci ; 53(9): 5737-47, 2012 Aug 20.
Article in English | MEDLINE | ID: mdl-22789924

ABSTRACT

PURPOSE: Individuals with oculocutaneous albinism are predisposed to visual system abnormalities affecting the retina and retinofugal projections, which may lead to reduced visual acuity and Infantile Nystagmus Syndrome (INS). Due to absence of an established mammalian animal model, mechanisms underlying INS remain elusive. In this study, we screened wild-type mice of varying pigmentation for ocular motor abnormalities in order to identify a possible mouse model for INS. METHODS: Three albino mouse strains (CD1, BALB/c, DBA/1), and two normally pigmented strains (129S6, C57BL/6) were screened using infrared oculography. Varying visual stimuli (black or white background, stationary pattern, optokinetic, i.e., horizontally rotating pattern) were displayed to the full (fVF) or anterior visual field (aVF) of the restrained mouse. RESULTS: We found spontaneous nystagmus, specifically jerks and oscillations, in albino mice under all experimental conditions. Median eye velocity was between 0.8 and 3.4 deg/s, depending on the strain. In contrast, the eyes in pigmented mice were nearly stable with a median absolute eye velocity of below 0.4 deg/s. In albino mice, fVF optokinetic stimuli elicited an optokinetic response (OKR) in the correct direction, albeit with superimposed oscillations. However, aVF optokinetic stimuli evoked reversed OKR in these strains, a well known feature of INS. CONCLUSIONS: Based on our results, we endorse the investigated albino mouse strains as new animal models for INS.


Subject(s)
Albinism, Oculocutaneous/etiology , Disease Models, Animal , Nystagmus, Congenital/etiology , Albinism, Oculocutaneous/diagnosis , Albinism, Oculocutaneous/physiopathology , Animals , Male , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Mice, Inbred DBA , Nystagmus, Congenital/diagnosis , Nystagmus, Congenital/physiopathology , Nystagmus, Optokinetic/physiology
13.
PLoS One ; 7(4): e35256, 2012.
Article in English | MEDLINE | ID: mdl-22523578

ABSTRACT

The metabotropic glutamate receptor 6 (mGluR6 or GRM6) belongs to the class III of the metabotropic glutamate receptor family. It is the only known mGluR that mediates direct synaptic transmission in the nervous system and is thought to mediate the ON-response in the ON-pathway of the vertebrate retina. Phylogenetic and gene structure analysis indicated that the zebrafish genome harbours two mglur6 paralogs, mglur6a and mglur6b. Besides expression in the inner nuclear layer and distinct regions in the brain, both mglur6 paralogs are expressed in ganglion cells of the retina, an expression pattern which can also be observed in the downstream effector molecules gnaoa and gnaob. This unexpected expression pattern is consistent with immunohistological labeling using a peptide antibody specific for the mGluR6b paralog. These expression patterns contradict the existing view that mGluR6 is solely located on ON-bipolar cells where it functions in signal transmission. Consistent with expression in ON-bipolar cells, we report a decreased b-wave amplitude in the electroretinogram after morpholino-based downregulation of mGluR6b, showing a function in the ON response. Our data suggest more widespread functions of mGluR6 mediated signaling in the central nervous system, possibly including sign reversing synapses in the inner retina.


Subject(s)
Receptors, Metabotropic Glutamate/genetics , Receptors, Metabotropic Glutamate/metabolism , Retinal Ganglion Cells/metabolism , Zebrafish/metabolism , Animals , Gene Expression , Phylogeny , Retina/metabolism , Synapses/metabolism , Synaptic Transmission/genetics , Zebrafish/genetics
14.
Rev Neurosci ; 22(1): 5-16, 2011.
Article in English | MEDLINE | ID: mdl-21615257

ABSTRACT

To ensure high acuity vision, eye movements have to be controlled with astonishing precision by the oculomotor system. Many human diseases can lead to abnormal eye movements, typically of the involuntary oscillatory eye movements type called nystagmus. Such nystagmus can be congenital (infantile) or acquired later in life. Although the resulting eye movements are well characterized, there is only little information about the underlying etiology. This is in part owing to the lack of appropriate animal models. In this review article, we describe how the zebrafish with its quick maturing visual system can be used to model oculomotor pathologies. We compare the characteristics and assessment of human and zebrafish eye movements. We describe the oculomotor properties of the zebrafish mutant belladonna, which has non-crossing optical fibers, and is a particularly informative model for human oculomotor deficits. This mutant displays a reverse optokinetic response, spontaneous oscillations that closely mimic human congenital nystagmus and abnormal motor behavior linked to circular vection.


Subject(s)
Disease Models, Animal , Ocular Motility Disorders , Zebrafish , Animals , Biological Clocks , Eye Movements , Humans , Ocular Motility Disorders/genetics , Ocular Motility Disorders/physiopathology , Reflex, Vestibulo-Ocular
16.
Commun Integr Biol ; 3(4): 379-81, 2010 Jul.
Article in English | MEDLINE | ID: mdl-20798832

ABSTRACT

Zebrafish belladonna (bel) mutants carry a mutation in the lhx2 gene that encodes a Lim domain homeobox transcription factor, leading to a defect in the retinotectal axon pathfinding. As a result, a large fraction of homozygous bel mutants is achiasmatic. Achiasmatic bel mutants display ocular motor instabilities, both reserved optokinetic response (OKR) and spontaneous eye oscillations, and an unstable swimming behavior, described as looping. All these unstable behaviors have been linked to the underlying optic nerve projection defect. Looping has been investigated under different visual stimuli and shown to be vision dependent and contrast sensitive. In addition, looping correlates perfectly with reversed OKR and the spontaneous oscillations of the eyes. Hence, it has been hypothesized that looping is a compensatory response to the perception of self-motion induced by the spontaneous eye oscillations. However, both ocular and postural instabilities could also be caused by a yet unidentified vestibular deficit. Here, we performed a preliminary test of the vestibular function in achiasmatic bel larval mutants in order to clarify the potential role of a vestibular deficit in looping. We found that the vestibular ocular reflex (VOR) is normally directed in both bel mutants and wild types and therefore exclude the possibility that nystagmus and looping in reverse to the rotating optokinetic drum can be attributed to an underlying vestibular deficit.

17.
PLoS One ; 4(8): e6550, 2009 Aug 12.
Article in English | MEDLINE | ID: mdl-19672291

ABSTRACT

Zebrafish mutant belladonna (bel) carries a mutation in the lhx2 gene (encoding a Lim domain homeobox transcription factor) that results in a defect in retinotectal axon pathfinding, which can lead to uncrossed optic nerves failing to form an optic chiasm. Here, we report on a novel swimming behavior of the bel mutants, best described as looping. Together with two previously reported oculomotor instabilities that have been related to achiasmatic bel mutants, reversed optokinetic response (OKR) and congenital nystagmus (CN, involuntary conjugate oscillations of both eyes), looping opens a door to study the influence of visual input and eye movements on postural balance. Our result shows that looping correlates perfectly with reversed OKR and CN and is vision-dependent and contrast sensitive. CN precedes looping and the direction of the CN slow phase is predictive of the looping direction, but is absent during looping. Therefore, looping may be triggered by CN in bel. Moreover, looping in wild-type fish can also be evoked by whole-field motion, suggesting that looping in a bel mutant larvae is a result of self-motion perception. In contrary to previous hypotheses, our findings indicate that postural control in vertebrates relies on both direct visual input (afference signal) and eye-movement-related signals (efference copy or reafference signal).


Subject(s)
Motion Perception , Zebrafish/physiology , Animals , Behavior, Animal , Eye Movements , LIM-Homeodomain Proteins , Mutation , Nerve Tissue Proteins/genetics , Transcription Factors , Zebrafish/genetics , Zebrafish Proteins/genetics
18.
Front Biosci ; 13: 1899-916, 2008 Jan 01.
Article in English | MEDLINE | ID: mdl-17981678

ABSTRACT

The optokinetic response (OKR) is a stereotyped eye movement in response to movement in he surround. The OKR serves to stabilize the visual image on the retina, and allows for high resolution vision. Due to its high selection value, all vertebrates display this basic behavior. Here, we review the properties of the OKR with a focus on the zebrafish, including methodological aspects of measuring eye movements in small larvae. The genetic amenabilities of the zebrafish model permit the use of this reflexive behavior in genetic screens. Such approaches have led to the isolation of mutant strains with specific defects in the visual pathway. In addition to the use of the OKR as a screening assay, mutations with characteristic abnormalities in the execution of this behavior will enable the analysis of sensory-motor control in great detail. A case in point is the belladonna mutation, where an axonal misrouting effect at the optic chiasm leads to a reversed OKR with a number of interesting properties.


Subject(s)
Eye Movements , Eye/metabolism , Ocular Physiological Phenomena , Animals , Humans , Kinetics , Mutation , Saccades/physiology , Vertebrates/metabolism , Vision, Ocular , Visual Pathways , Zebrafish , Zebrafish Proteins/physiology
19.
Bioorg Med Chem ; 15(16): 5493-501, 2007 Aug 15.
Article in English | MEDLINE | ID: mdl-17574421

ABSTRACT

The interaction of berberine and its 9-substituted derivatives with human telomeric DNA d[G(3)(T(2)AG(3))(3)](telo21) has been investigated via CD spectroscopy, fluorescence spectroscopy, PCR-stop assay, competitive dialysis, and telomerase repeat amplification protocol (TRAP) assay. The results indicated that these semisynthesized compounds could induce and stabilize the formation of anti-parallel G-quadruplex of telomeric DNA in the presence or absence of metal cations. Compared with berberine, the 9-substituted derivatives exhibit stronger binding affinity with G-quadruplex and higher inhibitory activity for telomerase. Introduction of a side chain with proper length of methylene and terminal amino group to the 9-position of berberine would significantly strengthen the binding affinity with G-quadruplex, resulting in increasing inhibitory effects on the amplification of telo21 DNA and on the telomerase activity.


Subject(s)
Berberine/analogs & derivatives , DNA/chemistry , Telomere/chemistry , Berberine/chemical synthesis , Berberine/chemistry , Berberine/pharmacology , Cations/chemistry , Cell Line, Tumor , Circular Dichroism , DNA/genetics , DNA/metabolism , G-Quadruplexes , Gene Amplification/genetics , Humans , Inhibitory Concentration 50 , Ligands , Metals/chemistry , Molecular Structure , Structure-Activity Relationship , Telomerase/antagonists & inhibitors , Telomerase/metabolism , Telomere/genetics , Telomere/metabolism
20.
J Neurosci ; 26(39): 9873-80, 2006 Sep 27.
Article in English | MEDLINE | ID: mdl-17005851

ABSTRACT

A large fraction of homozygous zebrafish mutant belladonna (bel) larvae display a reversed optokinetic response (OKR) that correlates with failure of the retinal ganglion cells to cross the midline and form the optic chiasm. Some of these achiasmatic mutants display strong spontaneous eye oscillations (SOs) in the absence of motion in the surround. The presentation of a stationary grating was necessary and sufficient to evoke SO. Both OKR reversal and SO depend on vision and are contrast sensitive. We built a quantitative model derived from bel fwd (forward) eye behaviors. To mimic the achiasmatic condition, we reversed the sign of the retinal slip velocity in the model, thereby successfully reproducing both reversed OKR and SO. On the basis of the OKR data, and with the support of the quantitative model, we hypothesize that the reversed OKR and the SO can be completely attributed to RGC misrouting. The strong resemblance between the SO and congenital nystagmus (CN) seen in humans with defective retinotectal projections implies that CN, of so far unknown etiology, may be directly caused by a projection defect.


Subject(s)
Disease Models, Animal , Nerve Tissue Proteins/deficiency , Nystagmus, Optokinetic/physiology , Nystagmus, Pathologic/genetics , Optic Chiasm/pathology , Retinal Ganglion Cells/pathology , Zebrafish Proteins/deficiency , Zebrafish/physiology , Animals , Axons/pathology , Computer Simulation , Contrast Sensitivity/genetics , Contrast Sensitivity/physiology , Crosses, Genetic , Eye Movements/genetics , Eye Movements/physiology , LIM-Homeodomain Proteins , Larva , Models, Neurological , Morphogenesis/genetics , Motion Perception/physiology , Nerve Tissue Proteins/genetics , Nystagmus, Optokinetic/genetics , Nystagmus, Pathologic/congenital , Nystagmus, Pathologic/pathology , Photic Stimulation , Transcription Factors , Zebrafish/anatomy & histology , Zebrafish/genetics , Zebrafish Proteins/genetics
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