• Journal of Microbiology
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• v.44 no.6
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• pp.665-670
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• 2006

Amyloid $\beta$-peptide (A$\beta$), which is a product of the proteolytic effect of $\beta$-secretase (BACE) on an amyloid precursor protein, is closely associated with Alzheimer's disease (AD) pathogenesis. There is sufficient evidence to suggest that a BACE inhibitor may reduce A$\beta$ levels, thus decreasing the risk of AD. In a previous study, an extract of Clavicorona pyxidata DGUM 29005 mycelia was found to inhibit the production of a soluble $\beta$-amyloid precursor protein (s$\beta$APP), A$\beta$, and BACE in neuronal cell lines. We sought to determine whether this mycelial extract exerts the same effect in human rhabdomyosarcoma A-204 and rat pheochromocytoma PC-12 cells. We found that the production of A$\beta$ decreased in a dose-dependent manner in the presence of the mycelial extract and that the concentration of A$\beta$ never exceeded $50{\mu}g/ml$. The presence of sAPP was detected in every culture medium to which the mycelial extract had been added and its concentration remained the same, regardless of the concentration of the extract used. Endogenous $\beta$-secretase activity in A-204 and PC-12 cellular homogenates also decreased in the presence of this extract. These cells, in culture, were not susceptible to the cytotoxic activity of the mycelial extract.

• The Korean Journal of Physiology and Pharmacology
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• v.13 no.3
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• pp.195-200
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• 2009

Zinc released from excited glutamatergic neurons accelerates amyloid ${\beta}$ (A ${\beta}$) aggregation, underscoring the therapeutic potential of zinc chelation for the treatment of Alzheimer's disease (AD). Zinc can also alter A ${\beta}$ concentration by affecting its degradation. In order to elucidate the possible role of zinc influx in secretase-processed A ${\beta}$ production, SH-SY5Y cells stably expressing amyloid precursor protein (APP) were treated with pyrrolidine dithiocarbamate (PDTC), a zinc ionophore, and the resultant changes in APP processing were examined. PDTC decreased A ${\beta}$ 40 and A ${\beta}$ 42 concentrations in culture media bathing APP-expressing SH-SY5Y cells. Measuring the levels of a series of C-terminal APP fragments generated by enzymatic cutting at different APP-cleavage sites showed that both ${\beta}$-and ${\alpha}$-cleavage of APP were inhibited by zinc influx. PDTC also interfered with the maturation of APP. PDTC, however, paradoxically increased the intracellular levels of A ${\beta}$ 40. These results indicate that inhibition of secretase-mediated APP cleavage accounts -at least in part- for zinc inhibition of A ${\beta}$ secretion.

• Korean Journal of Veterinary Research
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• v.48 no.3
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• pp.251-258
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• 2008

The neurotoxicity of C-terminal fragments of amyloid precusor protein (CT) is known to play some roles in Alzheimer's disease progression. In this study, we investigated the effects of the recombinant C-terminal 105 amino acid fragment of amyloid precusor protein (CT105) on cholinergic function using CT105-injected rat. To study the effects of CT105 on septohippocampal pathway, choline acetyltransferase (ChAT) positive neurons were examined in the medial septum and in the diagonal band after an injection of CT105 peptide into the lateral ventricle. Immunohistological analysis revealed that the number of ChAT-immunopositive cells decreased significantly in both medial septum and diagonal band. In addition, CT105 decreased ChAT-immunopositive cells in the hippocampal area, particulary in the dentate gyros. To study the effect of amyloid beta peptide ($A{\beta}$) and CT105 on the cholinergic system, each peptide was injected into the left lateral ventricle, and acetylcholine (ACh) levels were monitored in hippocampus. ACh level in the hippocampal area was reduced to 60% of control level in $A{\beta}$-treated group, and the level was reduced to 15% of control level in CT105-treated group, at one week after the injection. ACh level was further reduced to 35% of control in $A{\beta}$-treated group, whereas the level was slightly increased to 30% of control in CT105-treated group at 4 weeks after the injection. Taken together, the results in the present study suggest that CT105 impairs the septohippocampal pathway by reducing acetylcholine synthesis and release, which results in damage of learning and memory.

• Korean Journal of Veterinary Service
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• v.25 no.4
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• pp.377-384
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• 2002

In this study, to assess the diagnostic value for mastitis in dairy cows, change of acute phase proteins(haptoglobin and serum amyloid A) concentrations in milk and sera of dairy cows were measured. 50 dairy cows were used in this experiment and divided into two groups. The first group was the healthy dairy cow group whose milk contained less than 2.0${\times}$10$\^$5/ somatic cell counts(n=5). The second group was the mastitis-dairy cow group whose milk counted higher than 5.0${\times}$10$\^$5/ somatic cell counts(n=45). The concentration of haptoglobin and serum amyloid A in milk and sera from these two groups were determined by Tridelta range haptoglobin kit and serum amyloid A kit. The concentration of haptoglobin in the milk from first group was undetectable value and that of the second group was 124.0$\mu\textrm{g}$/$m\ell$. And the concentration of haptoglobin in serum of the first group was 32.0$\mu\textrm{g}$/$m\ell$ and that of the second group was 214.4$\mu\textrm{g}$/$m\ell$. The concentration of serum amyloid A in the milk from first group was 0.32$\mu\textrm{g}$/$m\ell$ and that of the second group was 17.7$\mu\textrm{g}$/$m\ell$. And the concentration of serum amyloid A in serum of the first group was 5.1$\mu\textrm{g}$/$m\ell$ and that of the second group was 25.8$\mu\textrm{g}$/$m\ell$. It was concluded that concentration of haptoglobin and serum amyoid A in milk and serum may be was to discriminate between normal and mastitic milks.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.7
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• pp.621-627
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• 2017

The understanding of the mechanical properties of amyloid fibers, which induce various neurodegenerative diseases, is directly related to the amyloid growth mechanism. Diverse studies have been performed on amyloid fibers from the viewpoint of disease epidemiology. Recently, attempts have been made to use amyloid fibers as new materials because of their notable mechanical properties and self-aggregation abilities. In this study, the mechanical properties of transthyretin (TTR105-115), which induces cardiovascular disease, were evaluated using a molecular dynamics (MD) simulation. In particular, the effect of the end-terminal capping on the structural stability of TTR105-115 was evaluated. The mechanical behavior and properties of TTR105-115 were measured by steered molecular dynamics (SMD). We clarified the factors affecting the mechanical properties of these materials and suggested the possibility of utilizing them as nature inspired materials.

• Biomedical Science Letters
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• v.24 no.4
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• pp.418-425
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• 2018

Amyloid brain positron emission tomography (PET) images are visually and subjectively analyzed by the physician with a lot of time and effort to determine the ${\beta}$-Amyloid ($A{\beta}$) deposition. We designed a convolutional neural network (CNN) model that predicts the $A{\beta}$-positive and $A{\beta}$-negative status. We performed 18F-florbetaben (FBB) brain PET on controls and patients (n=176) with mild cognitive impairment and Alzheimer's Disease (AD). We classified brain PET images visually as per the on the brain amyloid plaque load score. We designed the visual geometry group (VGG16) model for the visual assessment of slice-based samples. To evaluate only the gray matter and not the white matter, gray matter masking (GMM) was applied to the slice-based standard samples. All the performance metrics were higher with GMM than without GMM (accuracy 92.39 vs. 89.60, sensitivity 87.93 vs. 85.76, and specificity 98.94 vs. 95.32). For the patient-based standard, all the performance metrics were almost the same (accuracy 89.78 vs. 89.21), lower (sensitivity 93.97 vs. 99.14), and higher (specificity 81.67 vs. 70.00). The area under curve with the VGG16 model that observed the gray matter region only was slightly higher than the model that observed the whole brain for both slice-based and patient-based decision processes. Amyloid brain PET images can be appropriately analyzed using the CNN model for predicting the $A{\beta}$-positive and $A{\beta}$-negative status.

• The Journal of Korean Physical Therapy
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• v.33 no.3
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• pp.136-141
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• 2021

Purpose: Dementia is a disease in which cognitive function declines, leading to deterioration of body functions and activities of daily living. The purpose of this study is to explore the effects of dual-task training, including cognitive tasks, on cognitive and body function and β-amyloid levels in Alzheimer's dementia patients. Methods: 34 inpatients diagnosed with Alzheimer's dementia at a nursing hospital located in South Korea. The patients were randomly divided into a dual-task group (n=16) and a single-task group (n=18). Each group was trained for 30 minutes three times a week for eight weeks. The MMSE-K was used to measure the patients' cognitive function. To assess the patients' static balance ability, their LOS was measured using BioRescue. while dynamic balance was measured using the BBS. The 10MWT were conducted to evaluate the patients' walking ability. Blood analysis was performed to measure levels of β-amyloid. Results: Both groups exhibited statistically significant improvements in gait function after the training (p<0.05). The dual-task group exhibited statistically significant differences in cognitive function, static and dynamic balance function, and β-amyloid levels after training (p<0.05). A significant difference was observed between the two groups (p<0.05). Conclusion: Dual-task training were found to be effective in improving cognitive and bodily functioning and reducing β-amyloid levels in Alzheimer's dementia patients. Thus, this may be suggested as an effective exercise method for the treatment and early prevention of Alzheimer's dementia.

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2002.11a
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• pp.191-191
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• 2002

• Bulletin of the Korean Chemical Society
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• v.35 no.11
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• pp.3369-3372
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• 2014

• Bulletin of the Korean Chemical Society
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• v.30 no.6
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• pp.1237-1238
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• 2009