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1.
Healthcare (Basel) ; 10(12)2022 Dec 13.
Article in English | MEDLINE | ID: mdl-36554045

ABSTRACT

Fetal structural congenital abnormalities (SCAs) complicate 2-3% of all pregnancies. Whole-exome sequencing (WES) has been increasingly adopted prenatally when karyotyping and chromosomal microarray do not yield a diagnosis. This is a retrospective cohort study of 104 fetuses with SCAs identified on antenatal ultrasound in Hong Kong, where whole exome sequencing is performed. Molecular diagnosis was obtained in 25 of the 104 fetuses (24%). The highest diagnostic rate was found in fetuses with multiple SCAs (29.2%), particularly those with involvement of the cardiac and musculoskeletal systems. Variants of uncertain significance were detected in 8 out of the 104 fetuses (7.7%). Our study shows the utility of WES in the prenatal setting, and the extended use of the technology would be recommended in addition to conventional genetic workup.

2.
ACS Omega ; 7(43): 39463-39470, 2022 Nov 01.
Article in English | MEDLINE | ID: mdl-36340143

ABSTRACT

In this work, silicone nanofilament (SNF) coatings were prepared via a droplet-assisted growth and shaping (DAGS) approach, where the preparation of the coatings is allowed under ambient conditions. The application of SNF coatings as catalyst supports for amino moieties from (3-aminopropyl)triethoxysilane (APTES) was investigated. With the optimized coating conditions identified, the Brunauer-Emmett-Teller surface areas of a bare glass filter substrate and bare glass beads after the coating have increased by 5-fold and 16-fold, respectively. The SNF-coated filters were readily functionalized with amino groups via a liquid-phase deposition process, and their catalytic activities for a Knoevenagel reaction were evaluated using a batch reactor and a packed bed reactor. In both reactors, the as-prepared filters demonstrated superior catalytic performance over the functionalized filters without SNF coatings. Notably, the unique flexibility of the SNF coatings allowed the facile preparation of a packed bed reactor and a scalable catalytic system. It is expected that the packed bed system established in this study will support the development and the use of various SNF-supported organocatalysts and catalytic materials.

3.
Small ; 18(40): e2203820, 2022 10.
Article in English | MEDLINE | ID: mdl-35971157

ABSTRACT

One-dimensional silicone nanostructures, such as filaments, wires, and tubes, have attracted significant attention, owing to their remarkable application capabilities in a large range of material and surface science. However, the soft mechanical properties of silicone cause vulnerability and irregularity in the synthesized structures, which limits their applications. Herein, a simple, solvent-free, and efficient dynamic Droplet Assisted Growth and Shaping (d-DAGS) strategy is proposed for the one-step synthesis and in situ control of the shape of silicone nanostructures. The special designed bamboo-shaped silicone nanorods (SNRs) that are produced by the repetitive dynamic regulation of growth conditions, concomitant with the periodic purging and injection of precursors, exhibit highly-regular and tunable structure with a specific number of segments, indicating that they can be tailor-made according to the requirements of various properties. The enhanced mechanical stiffness and chemical durability strongly support their excellent performances in water-resistance under both static and dynamic wetting conditions. The SNRs significantly promote buoyancy and self-cleaning properties; and exhibit very high water-harvesting efficiency compared with existing designs. Notably, the well-structured ultra-long rods with an ultrahigh aspect ratio (≈176) can also be fabricated by the d-DAGS method, and they can remain standing straight upwards and regular, even though they consist of flexible silicone.


Subject(s)
Nanostructures , Nanotubes , Nanostructures/chemistry , Silicones , Water/chemistry
4.
J Med Internet Res ; 22(3): e16769, 2020 03 27.
Article in English | MEDLINE | ID: mdl-32217498

ABSTRACT

BACKGROUND: Technological surrogate nursing (TSN) derives from the idea that nurse-caregiver substitutes can be created by technology to support chronic disease self-care. OBJECTIVE: This paper begins by arguing that TSN is a useful and viable approach to chronic disease self-care. The analysis then focuses on the empirical research question of testing and demonstrating the effectiveness and safety of prototype TSN supplied to patients with the typical complex chronic disease of coexisting type 2 diabetes and hypertension. At the policy level, it is shown that the data allow for a calibration of TSN technology augmentation, which can be readily applied to health care management. METHODS: A 24-week, parallel-group, randomized controlled trial (RCT) was designed and implemented among diabetic and hypertensive outpatients in two Hong Kong public hospitals. Participants were randomly assigned to an intervention group, supplied with a tablet-based TSN app prototype, or to a conventional self-managing control group. Primary indices-hemoglobin A1c, systolic blood pressure, and diastolic blood pressure-and secondary indices were measured at baseline and at 8, 12, 16, and 24 weeks after initiation, after which the data were applied to test TSN effectiveness and safety. RESULTS: A total of 299 participating patients were randomized to the intervention group (n=151) or the control group (n=148). Statistically significant outcomes that directly indicated TSN effectiveness in terms of hemoglobin 1c were found in both groups but not with regard to systolic and diastolic blood pressure. These findings also offered indirect empirical support for TSN safety. Statistically significant comparative changes in these primary indices were not observed between the groups but were suggestive of an operational calibration of TSN technology augmentation. Statistically significant changes in secondary indices were obtained in one or both groups, but not between the groups. CONCLUSIONS: The RCT's strong behavioral basis, as well as the importance of safety and effectiveness when complex chronic illness is proximately self-managed by layperson patients, prompted the formulation of the empirical joint hypothesis that TSN would improve patient self-care while satisfying the condition of patient self-safety. Statistical and decision analysis applied to the experimental outcomes offered support for this hypothesis. Policy relevance of the research is demonstrated by the derivation of a data-grounded operational calibration of TSN technology augmentation with ready application to health care management. TRIAL REGISTRATION: ClinicalTrials.gov NCT02799953; https://clinicaltrials.gov/ct2/show/NCT02799953.


Subject(s)
Diabetes Mellitus, Type 2/nursing , Diabetes Mellitus, Type 2/therapy , Hypertension/nursing , Hypertension/therapy , Nursing Care/methods , Female , Humans , Male , Middle Aged , Self Care
5.
J Am Heart Assoc ; 9(6): e010240, 2020 03 17.
Article in English | MEDLINE | ID: mdl-32157956

ABSTRACT

Background Pin2/TRF1-interacting protein, PinX1, was previously identified as a tumor suppressor. Here, we discovered a novel transcript variant of mPinX1 (mouse PinX1), mPinX1t (mouse PinX1t), in embryonic stem cells (ESCs). The aims of this investigation were (1) to detect the presence of mPinX1 and mPinX1t in ESCs and their differentiation derivatives; (2) to investigate the role of mPinX1 and mPinX1t on regulating the characteristics of undifferentiated ESCs and the cardiac differentiation of ESCs; (3) to elucidate the molecular mechanisms of how mPinX1 and mPinX1t regulate the cardiac differentiation of ESCs. Methods and Results By 5' rapid amplification of cDNA ends, 3' rapid amplification of cDNA ends, and polysome fractionation followed by reverse transcription-polymerase chain reaction, mPinX1t transcript was confirmed to be an intact mRNA that is actively translated. Western blot confirmed the existence of mPinX1t protein. Overexpression or knockdown of mPinX1 (both decreased mPinX1t expression) both decreased while overexpression of mPinX1t increased the cardiac differentiation of ESCs. Although both mPinX1 and mPinX1t proteins were found to bind to cardiac transcription factor mRNAs, only mPinX1t protein but not mPinX1 protein was found to bind to nucleoporin 133 protein, a nuclear pore complex component. In addition, mPinX1t-containing cells were found to have a higher cytosol-to-nucleus ratio of cardiac transcription factor mRNAs when compared with that in the control cells. Our data suggested that mPinX1t may positively regulate cardiac differentiation by enhancing export of cardiac transcription factor mRNAs through interacting with nucleoporin 133. Conclusions We discovered a novel transcript variant of mPinX1, the mPinX1t, which positively regulates the cardiac differentiation of ESCs.


Subject(s)
Cell Cycle Proteins/metabolism , Cell Differentiation , Mouse Embryonic Stem Cells/metabolism , Myocytes, Cardiac/metabolism , Tumor Suppressor Proteins/metabolism , Animals , Cell Cycle Proteins/genetics , Cell Line , Cell Lineage , Gene Expression Regulation, Developmental , Mice , Minor Histocompatibility Antigens/genetics , Minor Histocompatibility Antigens/metabolism , Morphogenesis , Nuclear Pore Complex Proteins/genetics , Nuclear Pore Complex Proteins/metabolism , Protein Isoforms , RNA, Messenger/genetics , RNA, Messenger/metabolism , Signal Transduction , Transcription Factors/genetics , Transcription Factors/metabolism , Transcription, Genetic , Tumor Suppressor Proteins/genetics
6.
ACS Nano ; 11(9): 8953-8961, 2017 09 26.
Article in English | MEDLINE | ID: mdl-28813141

ABSTRACT

With intrinsic safety and much higher energy densities than supercapacitors, rechargeable nickel/cobalt-zinc-based textile batteries are promising power sources for next generation personalized wearable electronics. However, high-performance wearable nickel/cobalt-zinc-based batteries are rarely reported because there is a lack of industrially weavable and knittable highly conductive yarns. Here, we use scalably produced highly conductive yarns uniformly covered with zinc (as anode) and nickel cobalt hydroxide nanosheets (as cathode) to fabricate rechargeable yarn batteries. They possess a battery level capacity and energy density, as well as a supercapacitor level power density. They deliver high specific capacity of 5 mAh cm-3 and energy densities of 0.12 mWh cm-2 and 8 mWh cm-3 (based on the whole solid battery). They exhibit ultrahigh rate capabilities of 232 C (liquid electrolyte) and 116 C (solid electrolyte), which endows the batteries excellent power densities of 32.8 mW cm-2 and 2.2 W cm-3 (based on the whole solid battery). These are among the highest values reported so far. A wrist band battery is further constructed by using a large conductive cloth woven from the conductive yarns by a commercial weaving machine. It powers various electronic devices successfully, enabling dual functions of wearability and energy storage.

8.
Mol Neurodegener ; 9: 54, 2014 Nov 28.
Article in English | MEDLINE | ID: mdl-25432085

ABSTRACT

BACKGROUND: Recent epidemiological evidence suggests that modifying lifestyle by increasing physical activity could be a non-pharmacological approach to improving symptoms and slowing disease progression in Alzheimer's disease and other tauopathies. Previous studies have shown that exercise reduces tau hyperphosphorylation, however, it is not known whether exercise reduces the accumulation of soluble or insoluble tau aggregates and neurofibrillary tangles, which are both neuropathological hallmarks of neurodegenerative tauopathy. In this study, 7-month old P301S tau transgenic mice were subjected to 12-weeks of forced treadmill exercise and evaluated for effects on motor function and tau pathology at 10 months of age. RESULTS: Exercise improved general locomotor and exploratory activity and resulted in significant reductions in full-length and hyperphosphorylated tau in the spinal cord and hippocampus as well as a reduction in sarkosyl-insoluble AT8-tau in the spinal cord. Exercise did not attenuate significant neuron loss in the hippocampus or cortex. Key proteins involved in autophagy-microtubule-associated protein 1A/1B light chain 3 and p62/sequestosome 1 -were also measured to assess whether autophagy is implicated in the exercised-induced reduction of aggregated tau protein. There were no significant effects of forced treadmill exercise on autophagy protein levels in P301S mice. CONCLUSIONS: Our results suggest that forced treadmill exercise differently affects the brain and spinal cord of aged P301S tau mice, with greater benefits observed in the spinal cord versus the brain. Our work adds to the growing body of evidence that exercise is beneficial in tauopathy, however these benefits may be more limited at later stages of disease.


Subject(s)
Alzheimer Disease/metabolism , Tauopathies/metabolism , tau Proteins/genetics , Animals , Brain/metabolism , Disease Models, Animal , Mice, Transgenic , Nerve Degeneration/pathology , Physical Conditioning, Animal , Spinal Cord/metabolism
9.
Spine J ; 14(10): 2472-8, 2014 Oct 01.
Article in English | MEDLINE | ID: mdl-24735748

ABSTRACT

BACKGROUND CONTEXT: Periosteum, endosteum, and bone are innervated by sensory nerves expressing calcitonin gene-related peptide (CGRP), which is a known osteoanabolic peptide and plays an important role in fracture healing and spinal fusion. Synthesis and release of CGRP are found in sensory neurons located in the dorsal root ganglions (DRGs) and can be upregulated by electrical stimulation (ES) at DRG. PURPOSE: To prove our study hypothesis on the potential of precise ES at DRG through implantable microelectrical stimulation system (IMESS) for its effect on promoting spinal fusion in a rat model without decortications and bone grafting. STUDY DESIGN: An experimental animal study. METHODS: A novel IMESS was developed for stimulating L4-L6 DRG in rats. Sixteen rats were used and divided equally into the control group without ES and the ES group, with a daily 20 minutes ES to DRG for 6 weeks. At the end of 6 weeks, radiography and microcomputed tomography were conducted to evaluate new bone formation and spinal fusion. Bilateral L4-L6 DRGs were harvested for immunohistochemistry and quantification of neurons with upregulated CGRP expression. RESULTS: In the ES group, rate of radiographic fusion with complete and uninterrupted bony bridging was 100% (8/8) at the right L4/L5 transverse processes and 75% (6/8) at the right L5/L6 transverse processes. Bony callus formation was absent at the left L4-L6 transverse processes in the ES group and in bilateral L4-L6 transverse processes in the control group. CONCLUSIONS: We proved for the first time that precise ES at DRG through IMESS effectively promoted intertransverse process fusion in rat model without decortications and bone grafting. Electrical stimulation at DRG might be an attractive minimal invasive bioengineering approach and an alternative therapy for intertransverse process fusion that is increasingly being used for the treatment of degenerative spine disorders.


Subject(s)
Electric Stimulation/methods , Ganglia, Spinal/physiology , Lumbar Vertebrae/surgery , Sensory Receptor Cells/physiology , Spinal Fusion/methods , Animals , Bone Transplantation , Calcitonin Gene-Related Peptide/metabolism , Electrodes, Implanted , Female , Ganglia, Spinal/metabolism , Lumbar Vertebrae/metabolism , Rats , Rats, Sprague-Dawley , Sensory Receptor Cells/metabolism
10.
Hypertension ; 62(2): 295-301, 2013 Aug.
Article in English | MEDLINE | ID: mdl-23753418

ABSTRACT

D3 dopamine receptor (D3R)-deficient mice have renin-dependent hypertension associated with sodium retention, but the hypertension is mild. To determine whether any compensatory mechanisms in the kidney are involved in the regulation of blood pressure with disruption of Drd3, we measured the renal protein expression of all dopamine receptor subtypes (D1R, D2R, D4R, and D5R) in D3R homozygous (D3(-/-)) and heterozygous (D3(+/-)) knockout mice and their wild-type (D3(+/+)) littermates. The renal immunohistochemistry and protein expression of D5R were increased (n=5/group) in D3(-/-) mice; renal D4R protein expression was decreased, whereas renal protein expressions of D1R and D2R were similar in both groups. Renal D5R protein expression was also increased in D3(+/-) (n=5/group) relative to D3(+/+) mice, whereas D1R, D2R, and D4R protein expressions were similar in D3(+/-) and D3(+/+) mice. The increase in renal D5R protein expression was abolished when D3(-/-) mice were fed a high-salt diet. Treatment with the D1-like receptor antagonist, SCH23390, increased the blood pressure in anesthetized D3(-/-) but not D3(+/+) mice (n=4/group), suggesting that the renal upregulation of D5R may have minimized the hypertension in D3(-/-) mice. The renal D5R protein upregulation was not caused by increased transcription because renal mRNA expression of D5R was similar in D3(-/-) and D3(+/+) mice. Our findings suggest that the renal upregulation of D5R may have minimized the hypertension that developed in D3(-/-) mice.


Subject(s)
Hypertension/etiology , Kidney/physiology , Receptors, Dopamine D3/physiology , Receptors, Dopamine D5/physiology , Animals , Benzazepines/pharmacology , Hypertension/prevention & control , Immunohistochemistry , Mice , Mice, Inbred C57BL , Receptors, Dopamine D3/analysis , Receptors, Dopamine D5/analysis , Sodium/metabolism , Sodium Chloride, Dietary/administration & dosage , Up-Regulation
12.
Nanoscale ; 4(11): 3482-9, 2012 Jun 07.
Article in English | MEDLINE | ID: mdl-22552632

ABSTRACT

The first continuous, real-time spectroscopic monitoring of a photo-driven cargo delivery event from a mesoporous silica-based nanocarrier inside a single living cell is reported. By chemically attaching azobenzene molecules inside the 3 nm pore channels of mesoporous silica nanoparticles (∼70 nm diameter), the escape of the cargo molecule [propidium iodide (PI)] from the pore is prevented in the dark but is facilitated by the light-driven isomerization motion. Real-time spectroscopic measurements of a single cell uncover intermediate processes that occur during this intracellular delivery event, from nanomachine activation to the release of PI into the cytosol and to PI's eventual intercalation with nuclear DNA. Changes in PI's fluorescence intensity and the hypsochromic shift of the band maxima are used to identify the local environment of the fluorophore that is being observed in the cell. The ability to precisely initiate a chemical event inside an individual cell and continuously monitor the subsequent biological responses will enhance our understanding of intracellular process upon drug, protein and nucleic acid delivery.


Subject(s)
Nanoparticles/chemistry , Azo Compounds/chemistry , Cell Line , DNA/chemistry , Humans , Intercalating Agents/chemistry , Microscopy, Fluorescence , Porosity , Propidium/chemistry , Silicon Dioxide/chemistry
13.
Pharmacotherapy ; 32(1): 67-79, 2012 Jan.
Article in English | MEDLINE | ID: mdl-22392829

ABSTRACT

Many patients receive prolonged proton pump inhibitor (PPI) therapy for upper gastrointestinal disorders, but the long-term safety of PPIs, particularly increased risk of hip and nonhip fractures, has been questioned. To summarize the current literature on the risk of bone mineral density (BMD) reduction and fracture associated with PPI therapy, we conducted a literature search to identify all pertinent studies from 1980-February 2011. A total of 14 observational studies were included in this review. Most studies evaluated the risk of fracture associated with prolonged PPI exposure. Eight studies found an increased fracture risk at the hip, and five studies found an increased fracture risk at the spine associated with PPIs. Three studies showed reduction in fracture risk associated with PPIs after discontinuation for 1 month-1 year. Three studies evaluated the risk of BMD reduction associated with PPIs but did not find consistent changes in baseline or subsequent BMD. The current data suggest a modest increase in the risk of hip fracture and vertebral fracture associated with PPIs, although some studies showed conflicting results. Further studies will be needed to determine whether the increased risk of fracture is due to PPI exposure or residual confounding.


Subject(s)
Bone Density/drug effects , Fractures, Bone/chemically induced , Proton Pump Inhibitors/adverse effects , Bone Density/physiology , Fractures, Bone/epidemiology , Fractures, Bone/physiopathology , Humans , Risk Factors
14.
Neurosci Lett ; 505(3): 268-72, 2011 Nov 21.
Article in English | MEDLINE | ID: mdl-22040668

ABSTRACT

The etiology of neurodegenerative disorders like Parkinson's disease remains unknown, although many genetic and environmental factors are suggested as likely causes. Neuronal oxidative stress and mitochondrial dysfunction have been implicated as possible triggers for the onset and progression of Parkinson's neurodegeneration. We have recently shown that long-term treadmill exercise prevented neurological, mitochondrial and locomotor deficits in a chronic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine and probenecid-induced mouse model of Parkinson's disease that was originally established in our laboratory. In the present study, we further demonstrated that long-term exercise attenuated both cytochrome c release and elevated levels of p53, which are known to be associated with mitochondrial dysfunction in the striatum of this chronic model. On the other hand, the expressions of mitochondrial transcription factor A and peroxisome proliferator-activated receptor gamma coactivator 1α were unexpectedly upregulated in the striatum of this chronic model, but long-term exercise training brought their levels down closer to normal. Our findings suggest that maintaining normal mitochondrial function is essential for preventing the process of Parkinson's disease-like neurodegeneration, whereas stimulating the mitochondrial transcription factors for biogenesis is not obligatory.


Subject(s)
Corpus Striatum/metabolism , MPTP Poisoning/pathology , MPTP Poisoning/rehabilitation , Physical Conditioning, Animal/methods , Transcription Factors/metabolism , Adjuvants, Pharmaceutic/toxicity , Analysis of Variance , Animals , Chronic Disease , Corpus Striatum/pathology , Cytochromes c/metabolism , DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , Disease Models, Animal , Exercise Test , High Mobility Group Proteins/genetics , High Mobility Group Proteins/metabolism , MPTP Poisoning/chemically induced , Male , Mice , Mice, Inbred C57BL , Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha , Probenecid/toxicity , RNA, Messenger/metabolism , Trans-Activators/genetics , Trans-Activators/metabolism , Transcription Factors/genetics
15.
Pharmacol Biochem Behav ; 99(4): 704-11, 2011 Oct.
Article in English | MEDLINE | ID: mdl-21741988

ABSTRACT

Neuronal oxidative stress and mitochondrial dysfunction have been implicated in Parkinson's disease. Melatonin is a natural antioxidant and free radical scavenger that has been shown to effectively reduce cellular oxidative stress and protect mitochondrial functions in vitro. However, whether melatonin is capable of slowing down the neurodegenerative process in animal models of Parkinson's disease remains controversial. In this research, we examined long-term melatonin treatment on striatal mitochondrial and dopaminergic functions and on animal locomotor performance in a chronic mouse model of Parkinson's disease originally established in our laboratory by gradually treating C57BL/6 mice with 10 doses of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (15 mg/kg, s.c.) and probenecid (250 mg/kg, i.p.) over five weeks. We report here that when the chronic Parkinsonian mice were pre-treated and continuously treated with melatonin (5mg/kg/day, i.p.) for 18 weeks, the defects of mitochondrial respiration, ATP and antioxidant enzyme levels detected in the striatum of chronic Parkinson's mice were fully preempted. Meanwhile, the striatal dopaminergic and locomotor deficits seen in the chronic Parkinson's mice were partially and significantly forestalled. These results imply that long-term melatonin is not only mitochondrial protective but also moderately neuronal protective in the chronic Parkinson's mice. Melatonin may potentially be effective for slowing down the progression of idiopathic Parkinson's disease and for reducing oxidative stress and respiratory chain inhibition in other mitochondrial disorders.


Subject(s)
Antiparkinson Agents , Behavior, Animal/drug effects , Free Radical Scavengers/pharmacology , Melatonin/pharmacology , Mitochondria/metabolism , Neuroprotective Agents , Parkinsonian Disorders/metabolism , Parkinsonian Disorders/psychology , Adenosine Triphosphate/metabolism , Animals , Corpus Striatum/drug effects , Corpus Striatum/metabolism , MPTP Poisoning/drug therapy , MPTP Poisoning/psychology , Male , Mice , Mice, Inbred C57BL , Mitochondria/drug effects , Oxygen Consumption/drug effects , Parkinsonian Disorders/chemically induced , Postural Balance/drug effects , Probenecid , Psychomotor Performance/drug effects , Substantia Nigra/drug effects , Substantia Nigra/metabolism , Superoxide Dismutase/metabolism , Tubulin/metabolism
16.
Eur J Neurosci ; 33(7): 1264-74, 2011 Apr.
Article in English | MEDLINE | ID: mdl-21375602

ABSTRACT

The protective impact of exercise on neurodegenerative processes has not been confirmed, and the mechanisms underlying the benefit of exercise have not been determined in human Parkinson's disease or in chronic animal disease models. This research examined the long-term neurological, behavioral, and mechanistic consequences of endurance exercise in experimental chronic parkinsonism. We used a chronic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced mouse model of Parkinson's disease with moderate neurodegeneration and examined the effects of treadmill exercise on movement and balance coordination, changes in dopamine neuron biomarkers, mitochondrial functions, and neurotrophic factor activities in the nigrostriatal system. The exercise results were compared with those of the control and sedentary chronic parkinsonian animals. After 18 weeks of exercise training in the chronic parkinsonian mice, we observed a significant deterrence in the loss of neuronal dopamine-producing cells and other functional indicators. The impaired movement and balance incoordination in the chronic parkinsonian mice were also markedly reduced following exercise. Mechanistic investigations revealed that the neuronal and behavioral recovery produced by exercise in the chronic parkinsonian mice was associated with an improved mitochondrial function and an increase in the brain region-specific levels of brain-derived and glial cell line-derived neurotrophic factors. Our findings indicate that exercise not only produces neuronal and mitochondrial protection, it also boosts nigrostriatal neurotrophic factor levels in the chronic parkinsonian mice with moderate neurodegeneration. Therefore, modifying lifestyle with increased exercise activity would be a non-pharmacological neuroprotective approach for averting neurodegenerative processes, as demonstrated in experimental chronic parkinsonism.


Subject(s)
Disease Models, Animal , Nerve Degeneration/pathology , Parkinsonian Disorders/pathology , Parkinsonian Disorders/physiopathology , Physical Conditioning, Animal , Adjuvants, Pharmaceutic/pharmacology , Animals , Biomarkers/metabolism , Brain-Derived Neurotrophic Factor/metabolism , Corpus Striatum/cytology , Corpus Striatum/metabolism , Dopamine/metabolism , Exercise , Glial Cell Line-Derived Neurotrophic Factors/metabolism , Humans , Male , Mice , Mice, Inbred C57BL , Mitochondria/metabolism , Motor Activity/physiology , Neurons/cytology , Neurons/metabolism , Parkinson Disease/pathology , Parkinson Disease/physiopathology , Probenecid/pharmacology , Substantia Nigra/cytology , Substantia Nigra/metabolism , Superoxide Dismutase/metabolism
17.
Am J Physiol Renal Physiol ; 300(5): F1123-9, 2011 May.
Article in English | MEDLINE | ID: mdl-21325500

ABSTRACT

The current experiments explore the role of dopamine in facilitating the acute increase in renal phosphate excretion in response to a high-phosphate diet. Compared with a low-phosphate (0.1%) diet for 24 h, mice fed a high-phosphate (1.2%) diet had significantly higher rates of phosphate excretion in the urine associated with a two- to threefold increase in the dopamine content of the kidney and in the urinary excretion of dopamine. Animals fed a high-phosphate diet had a significant increase in the abundance and activity of renal DOPA (l-dihydroxyphenylalanine) decarboxylase and significant reductions in renalase, monoamine oxidase A, and monoamine oxidase B. The activity of protein kinase A and protein kinase C, markers of activation of renal dopamine receptors, were significantly higher in animals fed a high-phosphate vs. a low-phosphate diet. Treatment of rats with carbidopa, an inhibitor of DOPA decarboxylase, impaired adaptation to a high-phosphate diet. These experiments indicate that the rapid adaptation to a high-phosphate diet involves alterations in key enzymes involved in dopamine synthesis and degradation, resulting in increased renal dopamine content and activation of the signaling cascade used by dopamine to inhibit the renal tubular reabsorption of phosphate.


Subject(s)
Dopamine/metabolism , Kidney/metabolism , Phosphorus, Dietary/metabolism , Adaptation, Physiological , Analysis of Variance , Animals , Aromatic Amino Acid Decarboxylase Inhibitors , Carbidopa/pharmacology , Cyclic AMP-Dependent Protein Kinases/metabolism , Dopa Decarboxylase/metabolism , Dopamine/urine , Enzyme Inhibitors/pharmacology , Kidney/drug effects , Male , Mice , Mice, Inbred C57BL , Monoamine Oxidase/metabolism , Phosphorus, Dietary/administration & dosage , Phosphorus, Dietary/urine , Protein Kinase C/metabolism , Rats , Rats, Sprague-Dawley , Signal Transduction , Time Factors , Up-Regulation
18.
Pflugers Arch ; 461(1): 191-202, 2011 Jan.
Article in English | MEDLINE | ID: mdl-21110038

ABSTRACT

Embryonic stem cells (ESCs) can uniquely proliferate indefinitely and differentiate into all cell lineages. ESCs may therefore provide an unlimited supply of cells for cell-based therapies. Previous study reported the presence of hyperpolarization-activated inward currents in undifferentiated mouse (m) ESCs, but the functional role of this hyperpolarization-activated current in mESCs is unknown. In this study, the role of this current in maintaining the proliferative capacity and the cell cycle progression of ESCs was investigated. In D3 mESCs, this hyperpolarization-activated inward current can be blocked by HCN channel blocker ZD7288. Application of the HCN channel blockers, cesium (1-10 mM) or ZD7288 (0.1-30 µM), attenuated cell proliferation in a concentration-dependent manner. Both HCN blockers were found to be non-cytotoxic to mESCs as determined by cell viability test. Interestingly, ZD7288 at 10 and 30 µM was found to decrease the proportion of cells in G(0)/G(1) phase and increase the proportion of cells in S phase. This suggests that this hyperpolarization-activated current can affect the cell cycle progression in mESCs. In summary, the present investigation suggests that ESC proliferation and cell cycle progression can be regulated by this hyperpolarization-activated current.


Subject(s)
Cell Cycle/drug effects , Cell Proliferation/drug effects , Cyclic Nucleotide-Gated Cation Channels/antagonists & inhibitors , Embryonic Stem Cells/cytology , Animals , Cell Survival/drug effects , Cesium/pharmacology , Cyclic Nucleotide-Gated Cation Channels/metabolism , Cyclin B/biosynthesis , Embryonic Stem Cells/drug effects , Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels , Membrane Potentials , Mice , Patch-Clamp Techniques , Pyrimidines/pharmacology
19.
J Cell Physiol ; 224(1): 165-77, 2010 Jul.
Article in English | MEDLINE | ID: mdl-20333647

ABSTRACT

Embryonic stem cells (ESCs) possess two unique characteristics: self-renewal and pluripotency. In this study, roles of voltage-gated potassium channels (K(v)) in maintaining mouse (m) ESC characteristics were investigated. Tetraethylammonium (TEA(+)), a K(v) blocker, attenuated cell proliferation in a concentration-dependent manner. Possible reasons for this attenuation, including cytotoxicity, cell cycle arrest and differentiation, were examined. Blocking K(v) did not change the viability of mESCs. Interestingly, K(v) inhibition increased the proportion of cells in G(0)/G(1) phase and decreased that in S phase. This change in cell cycle distribution can be attributed to cell cycle arrest or differentiation. Loss of pluripotency as determined at both molecular and functional levels was detected in mESCs with K(v) blockade, indicating that K(v) inhibition in undifferentiated mESCs directs cells to differentiate instead of to self-renew and progress through the cell cycle. Membrane potential measurement revealed that K(v) blockade led to depolarization, consistent with the role of K(v) as the key determinant of membrane potential. The present results suggest that membrane potential changes may act as a "switch" for ESCs to decide whether to proliferate or to differentiate: hyperpolarization at G(1) phase would favor ESCs to enter S phase while depolarization would favor ESCs to differentiate. Consistent with this notion, S-phase-synchronized mESCs were found to be more hyperpolarized than G(0)/G(1)-phase-synchronized mESCs. Moreover, when mESCs differentiated, the differentiation derivatives depolarized at the initial stage of differentiation. This investigation is the first study to provide evidence that K(v) and membrane potential affect the fate determination of ESCs.


Subject(s)
Cell Differentiation , Cell Proliferation , Embryonic Stem Cells/metabolism , Pluripotent Stem Cells/metabolism , Potassium Channels, Voltage-Gated/metabolism , Potassium/metabolism , Animals , Biomarkers/metabolism , Cell Cycle , Cell Differentiation/drug effects , Cell Differentiation/genetics , Cell Line , Cell Proliferation/drug effects , Cell Survival , Dose-Response Relationship, Drug , Embryonic Stem Cells/drug effects , Gene Expression Regulation, Developmental , Membrane Potentials , Mice , Pluripotent Stem Cells/drug effects , Potassium Channel Blockers/pharmacology , Potassium Channels, Voltage-Gated/antagonists & inhibitors , Tetraethylammonium/pharmacology , Time Factors
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