The vertebrate retina is a clearly organized signal-processing system. It contains more than 60 different types of neurons, arranged in three distinct neural layers. Each cell type is believed to serve unique role(s) in encoding visual information. While we now have a relatively good understanding of the constituent cell types in the retina and some general ideas of their connectivity, with few exceptions, how the retinal circuitry performs computation remains poorly understood. Computational modeling has been commonly used to study the retina from the single cell to the network level. In this article, we begin by reviewing retinal modeling strategies and existing models. We then discuss in detail the significance and limitations of these models, and finally, we provide suggestions for the future development of retinal neural modeling.
The progression of breast cancer is increasing at an alarming rate, particularly in western countries. Meanwhile, the lower incidence in Asian countries could be attributed to the heavy incorporation of green leaves vegetables or spices in their diets. Murraya koenigii (MK) or often times known as curry leaves are common spice used mostly in tropical countries. Anti-inflammatory and chemopreventive effects of MK aqueous extract on 4T1 breast cancer cell-challenged mice were evaluated.
Neurodegenerative causes of blindness and deafness possess a major challenge in their clinical management as proper treatment guidelines have not yet been found. Brain-derived neurotrophic factor (BDNF) has been established as a promising therapy against neurodegenerative disorders including hearing and visual loss. Unfortunately, the blood-retinal barrier and blood-cochlear barrier, which have a comparable structure to the blood-brain barrier prevent molecules of larger sizes (such as BDNF) from exiting the circulation and reaching the targeted cells. Anatomical features of the eye and ear allow use of local administration, bypassing histo-hematic barriers. This paper focuses on highlighting a variety of strategies proposed for the local administration of the BDNF, like direct delivery, viral gene therapy, and cell-based therapy, which have been shown to successfully improve development, survival, and function of spiral and retinal ganglion cells. The similarities and controversies for BDNF treatment of posterior eye diseases and inner ear diseases have been analyzed and compared. In this review, we also focus on the possibility of translation of this knowledge into clinical practice. And finally, we suggest that using nanoparticulate drug-delivery systems may substantially contribute to the development of clinically viable techniques for BDNF delivery into the cochlea or posterior eye segment, which, ultimately, can lead to a long-term or permanent rescue of auditory and optic neurons from degeneration.
MicroRNAs (miRNAs) have a crucial role in gene expression regulation and protein synthesis, especially in the central nervous system. In developing mouse embryos a novel miRNA, miR-3099, is highly expressed, particularly in the central nervous system. This study aims to determine the expression of miR-3099 during cellular differentiation of 46C mouse embryonic stem cells after neural induction with N2/B27 medium.
Four commercial repellents were evaluated in the laboratory against Leptotrombidium deliense chiggers. Both in vitro and in vivo methods were used to determine repellency of the compounds. The repellents were Kellis (containing citronella oil, jojoba oil and tea tree oil), Kaps (containing citronella oil), BioZ (containing citronella oil, geranium oil and lemon grass oil) and Off (containing DEET). The combination of three active ingredients: citronella oil, geranium oil, lemon grass oil gave the highest repellency (87%) followed by DEET (84%). In vitro repellencies ranged from 73% to 87%. There was no significant difference between the four products. All the repellents had 100% in vivo repellency compared to 41-57% for the controls.
Hypnale hypnale (hump-nosed pit viper) is a medically important venomous snake in Sri Lanka and Southwestern India. Bite of this snake may result in hemostatic dysfunction, acute kidney injury and death. Clinical studies indicated that the locally available polyvalent antivenoms produced in India are not effective against hump-nosed pit viper envenoming. Hence, there is an urgent need to search for effective antivenom. In this paper, we examined the ability of Calloselasma rhodostoma (Malayan pit viper) monovalent antivenom and the Hemato polyvalent antivenom (both produced by Thai Red Cross Society, TRCS) to neutralize the lethality and toxic effects of H. hypnale venom, as C. rhodostoma is considered a sister taxon of H. hypnale. In vitro neutralization studies showed that the Hemato polyvalent antivenom effectively neutralized the lethality of H. hypnale venom (1.52mgvenom/mL antivenom) as well as the hemorrhagic, procoagulant and necrotic activities of the venom. The monovalent C. rhodostoma antivenom could also neutralize the lethality and toxic activities of the venom, but the potency was lower. The Hemato polyvalent antivenom also effectively protected mice from the lethal and local effects of H. hypnale venom in an in vivo rodent model of envenoming. Furthermore, the polyvalent antivenom could also effectively neutralize the venom of Daboia russelii (2.50mgvenom/mL antivenom), another common cause of snake bites in Sri Lanka and South India. These findings suggested that the Hemato polyvalent antivenom may be beneficial in the antivenom treatment of H. hypnale envenoming.
Six new linear peptides, pterulamides I-VI (1-6), were isolated from the fruiting bodies of a Malaysian Pterula species. The structures were elucidated by MS and 2D NMR experiments, and the absolute configurations of the constituent amino acids established using Marfey's method. The pterulamides are mainly assembled from nonpolar N-methylated amino acids and, most interestingly, have non-amino-acid N-terminal groups, among them the unusual cinnamoyl, (E)-3-methylsulfinylpropenoyl, and (E)-3-methylthiopropenoyl groups. Furthermore, pterulamides I-V are the first natural peptides with a methylamide C-terminus. Pterulamides I and IV are cytotoxic against the P388 cell line with IC50 values of 0.55 and 0.95 microg/mL (0.79 and 1.33 microM), respectively.
Introduction: The aims of this study were to assess the differences in the percentages of abnormal morphology between the epididymal and testicular spermatozoa of mature male offspring mice whose mothers were injected with various doses of lead acetate during gestation. Materials and Methods: Seventy two healthy female mice were divided into three major groups according to the number of injections involving 1, 2 or 3 injections at 8th day; 8th and 13th days; and 8th, 13th and 18th days of gestation period, respectively. Each major group was subdivided into four minor groups according to the dosage of lead administered (0, 25, 50 and 100) mg/Kg. Results: The percentages of abnormal morphology of epididymal and testicular spermatozoa were studied and the data were statistically analyzed. The results of this study proved that an increased number of injections and/or dose of lead acetate injected to the mothers during gestation cause an elevation in the percentage of abnormal morphology of both epididymal and testicular spermatozoa of the male mice offspring. Conclusion: In conclusion this study demonstrated that lead acetate when exposed prenatally have toxic effects on the sperm in the offspring male mice resulting in abnormal morphology of spermatozoa. The most likely causative factor is disturbances in the phase(s) of spermatogenesis and/or spermiogenesis.
Neural tube defects (NTDs) are the leading cause of disability in humans arising from the malformation of the central nervous system. The genes responsible and their involvement in causing neural tube defects in humans are poorly understood. Gene expression analysis in a whole organism enables the identification of the possible role of the gene being studied. If the gene is expressed in a particular tissue at a certain period of development, this spatiotemporal pattern of the gene of interest signals the possibility that the gene serves a function of being switched on in those tissues at that particular time. In this report, we have identified possible gene candidates in the mouse which may be required for the development of the neural tube, the precursor to the brain and the spinal cord. Development of the brain occurs by closure of the anterior neuropore (forms the cranial neural tube) while the spinal cord forms due to resolution of the posterior neuropore (forms the caudal neural tube). The genes Tiaml and T-cadherin were found to be likely candidate genes for the development of the spinal cord and may serve as potential human NTDs genes.
The detection of tetrodotoxin (TTX) and saxitoxin (STX) in dried salted yellow puffer fish (Xenopterus naritus) eggs bought from Satok Market, Kuching, Sarawak was carried out by mouse bioassay method. The amount of TTX and STX detected in the samples ranged from 95.6-195.5 Mouse Unit (MU)/g and 1.72-3.58 MU/g respectively. The results indicate that the dried salted eggs samples were found to contain TTX 9-20 times above the regulatory limit for human consumption (10 MU/g). Although detected, the amount of STX in salted eggs extract was slightly below the accepted threshold limit (4 MU/g). The local public in Sarawak should be educated on the potential danger of consuming dried salted puffer fish eggs in addition to the current warnings on puffer fish.
Venoms of Calliophis bivirgata and Calliophis intestinalis exhibited moderate binding activities toward Neuro Bivalent Antivenom (Taiwan) but not the other six elapid monovalent or bivalent antivenoms available in the region. All antivenoms failed to neutralize C. bivirgata venom lethality in mice. The findings indicate the need to validate antivenom cross-reactivity with in vivo cross-neutralization, and imply that distinct antigens of Calliophis venoms should be incorporated in the production of a pan-regional poly-specific antivenom.