Introduction : brain science : inside out

BRAIN – remains as the most sophisticated organ in the known universe. While more has been learned about it in the past two hundred years, we are still at a very early stage in our understanding. The field of Neuroscience is still in its infancy, but is rapidly exploding – turning many yesterday’s brain “myth” to today’s brain “facts”

The resin-embedded cornea prepared via rapid processing protocol : a good histomorphometric target for clinical investigation in opthalmology and optometry.

This study illustrates and quantifies the changes on corneal tissue between the paraffin-embedded and resin-embedded blocks and thus, selects a better target in investigational ophthalmology and optometry via light microscopy. Corneas of two cynomolgus monkeys (Macaca fascicularis) were used in this study. The formalin-fixed cornea was prepared in paraffin block via the conventional tissue processing protocol (4-day protocol) and stained with haematoxylin and eosin. The glutaraldehyde-fixed cornea was prepared in resin block via the rapid and modified tissue processing procedure (1.2-day protocol) and stained with toluidine blue. The paraffin-embedded sample exhibits various undesired tissue damage and artifact such as thinner epithelium (due to the substantial volumic extraction from the tissue), thicker stroma layer (due to the separation of lamellae and the presence of voids) and the distorted endothelium. In contrast, the resin-embedded corneal tissue has demonstrated satisfactory corneal ultrastructural preservation. The rapid and modified tissue processing method for preparing the resin-embedded is particularly beneficial to accelerate the microscopic evaluation in ophthalmology and optometry

Acute oral toxicity and biodistribution study of zinc aluminium-levodopa nanocomposite

Layered double hydroxide (LDH) is an inorganic-organic nano-layered material that harbours drug between its two-layered sheets, forming a sandwich-like structure. It is attracting a great deal of attention as an alternative drug delivery (nanodelivery) system in the field of pharmacology due to their relative low toxic potential. The production of these nanodelivery systems, aimed at improving human health through decrease toxicity, targeted delivery of the active compound to areas of interest with sustained release ability. In this study, we administered zinc-aluminium-LDH-levodopa nanocomposite (ZAL) and zinc-aluminium nanocomposite (ZA) to Sprague Dawley rats to evaluate for acute oral toxicity following OECD guidelines. The oral administration of ZAL and ZA at a limit dose of 2,000 mg/kg produced neither mortality nor acute toxic signs throughout 14 days of the observation. The percentage of body weight gain of the animals showed no significant difference between control and treatment groups. Animal from the two treated groups gained weight continuously over the study period, which was shown to be significantly higher than the weight at the beginning of the study (P < 0.05). Biochemical analysis of animal serum showed no significant difference between rats treated with ZAL, ZA and controls. There was no gross lesion or histopathological changes observed in vital organs of the rats. The results suggested that ZAL and ZA at 2,000 mg/kg body weight in rats do not induce acute toxicity in the animals. Elemental analysis of tissues of treated animals demonstrated the wider distribution of the nanocomposite including the brain. In summary, findings of acute toxicity tests in this study suggest that zinc-aluminium nanocomposite intercalated with and the un-intercalated were safe when administered orally in animal models for short periods of time. It also highlighted the potential distribution ability of Tween-80 coated nanocomposite after oral administration

smART Brain

In the smART Brain section, visitors can expect a dynamic yet entertaining science journey and educational time. “The Master Hat” is specially designed to portray the left-right brain dominance : the right brain is often regarded as the more creative side whilst the left brain is regarded as the analytical side

Histomorphometric profile of the corneal response to short-term reverse-geometry orthokeratology lens wear in primate corneas: a pilot study

Purpose: To investigate the histological changes in primate cornea induced by short-term overnight orthokeratology (OK). Methods: Nine young adult primates were used. One animal served as negative control. The remaining 8 animals wore reverse-geometry OK lenses for periods of 4, 8, 16, and 24 hours on 1 eye with the other eye as control. Central and midperipheral corneal thickness, as well as ultrastructural changes in corneal epithelium, stroma and endothelium in response to OK lenses, were evaluated. Results: OK significantly reduced the thickness of the central cornea in all treatment groups. The central corneal thinning was both stromal and epithelial in origin. Substantial midperipheral corneal thickening was seen in 16-hour and 24-hour lens-wear groups and this effect was both stromal and epithelial in origin as well. Histology evidence indicated the primary epithelial response in the central cornea was compression of cells that resulted in wing cells becoming shorter and basal cells being squatted rather than lost or migration of cell layers. These pronounced cell shape changes occurred without compromising the structural integrity of the desmosomes. The thickened corneal epithelium has normal cell layers. The squamous cells have larger surface sizes and are composed of oval instead of flattened nuclei. This implied delayed surface cell exfoliation at the thickened midperipheral epithelium. Physical presence of OK lens over the cornea did not influence the microstructures of microvilli and microplicae, endothelium, and collagen distribution. Conclusions: The primate cornea, particularly the corneal epithelium, responds rapidly to the application of reverse-geometry OK lenses with significant epithelial cell shape alterations with short-term OK lens wear. This finding suggests that the corneal epithelium is moldable in response to the physical forces generated by the OK lenses

Discovery of anatomic variant of saphenous nerve from human cadaver dissection

Introduction: Saphenous nerve is the longest and largest pure sensory nerve, supplying the medial side of the thigh, leg and foot. Materials and Methods: In the present case study, during routine cadaveric dissection of the antero-medial part of the thigh, an interesting anomalous pattern of saphenous nerve was seen in the right lower limb of a 62 years old embalmed male cadaver from the Department of Human Anatomy, Universiti Putra Malaysia (UPM). Results: This saphenous nerve can be recognised as an unusual anatomical variant in which it gives a motor branch to the sartorius muscle during traversing the adductor canal and it was accompanied by blood vessels at the same time. The nerve continues its usual course and pierces the fascia lata, between the tendon of sartorius and gracilis and becomes subcutaneous. Conclusion: Knowledge of the variant anatomy of the saphenous nerve is important to surgeon in avoiding nerve injuries during adductor canal nerve block, nerve entrapment surgery, reconstructive surgery, pain management services and knee surgery successfully

Expression of Notch-1 receptor and its ligands Jagged-1 and Delta-1 in amoeboid microglia in postnatal rat brain and murine BV-2 cells.

Notch-1 receptor signaling pathway is involved in neuronal and glial differentiation. Its involvement in microglial functions, however, has remained elusive. This study reports the localization of Notch-1 receptor immunoreactivity in the amoeboid microglial cells (AMC) in the postnatal rat brain. By immunofluorescence, Notch-1 receptor was colocalized with its ligands, Jagged-1 and Delta-1, in the AMC in the corpus callosum and subventricular zone. Notch-1 immunopositive cells were confirmed to be microglia labeled by OX42 and lectin. Immunoexpression of Notch-1 receptor was progressively reduced with age. Western blot analysis showed that Notch-1 protein level in the corpus callosum in which the AMC were heavily populated was concomitantly decreased. In postnatal rats challenged with lipopolysaccharide (LPS), Notch-1 receptor immunofluorescence in AMC was noticeably enhanced. Furthermore, Notch-1 protein level in the corpus callosum was increased as revealed by Western blotting analysis. In primary microglial culture treated with LPS, mRNA expression of Notch-1 and its ligand Jagged-1 was upregulated but that of Delta-1 was reduced. The expression pattern of Notch-1 and its ligands was confirmed in murine BV-2 cells. Furthermore, Notch-1 neutralization with its antibody reduced its protein expression. More importantly, neutralization of Notch-1 concomitantly suppressed the mRNA expression of IL-6, IL-1, M-CSF, and iNOS; TNF-α, mRNA expression, however, was enhanced. Western blot confirmed the changes of protein level of the above except for IL-6, which remained relatively unaltered. It is concluded that Notch-1 signaling in the AMC and LPS-activated microglia/BV-2 cells modulates the expression of proinflammatory cytokines and nitric oxide

Expression profiling of genes involved in the development and function of skeletal muscles in Ts1Cje mouse model of down syndrome

Introduction: Down syndrome (DS) is caused by trisomy of human chromosome 21 (HSA21). Motor dysfunction due to hypotonia has limited labour productivity and have significant effects on socio-economic status in DS individuals. Ts1Cje, a mouse model of DS that exhibits muscle weakness was employed, to investigate the expression profile of selected trisomic and disomic genes involved in skeletal muscle structure and function. Methods: Quadriceps and triceps were harvested from the Ts1Cje (C57BL/6) postnatal day 60-70 mice and corresponding wild-type littermates. Total RNA extracted from these tissues was subjected for quantitative expression profiling of three trisomic genes (Itsn1, Synj1 and Rcan1) involved in neurotransmission and six disomic genes (Lamc1, Leprel1, Myl6b, Msn, Pgm5 and Tmod1) essential for maintenance of muscle structure and function. Real-time quantitative PCR method was used for the profiling. Results: Differential gene expression in DS is reflected by 1.5-fold or more increase in the level of expression as predicted by the gene dosage imbalance hypothesis. The analysis showed no significant changes in the expression level of trisomic genes (Itsn1, Synj1 and Rcan1). On contrary, disomic genes, Leprel1 and Pgm5, were upregulated for more than 1.5-fold in DS quadriceps whereas Lamc1, Myl6b and Pgm5 were upregulated for more than 1.5 fold in DS triceps as compared to the wild-type group. Conclusions: Our findings suggest that the dysregulation of Lamc1, Leprel1, Myl6b and Pgm5 genes is associated to muscle weakness seen in Ts1Cje and may play a role in molecular pathogenesis of muscle weakness in DS

Challenges and future perspectives for 3D cerebral organoids as a model for complex brain disorders

The human brain is made up of billions of neurons and glial cells which are interconnected and organized into specific patterns of neural circuitry, and hence is arguably the most sophisticated organ in human, both structurally and functionally. Studying the underlying mechanisms responsible for neurological or neurodegenerative disorders and the developmental basis of complex brain diseases such as autism, schizophrenia, bipolar disorder, Alzheimer’s and Parkinson’s disease has proven challenging due to practical and ethical limitations on experiments with human material and the limitations of existing biological/animal models. Recently, cerebral organoids have been proposed as a promising and revolutionary model for understanding complex brain disorders and preclinical drug screening

The restoration of REST inhibits reactivity of Down syndrome iPSC-derived astrocytes

IntroductionAccumulating evidence indicates that the increased presence of astrocytes is fundamentally linked to the neurological dysfunctions observed in individuals with Down syndrome (DS). REST (RE1-silencing transcription factor), as a chromatin modifier, regulates 15,450 genes in humans. REST is a key regulatory element that governs astrocyte differentiation, development, and the maintenance of their physiological functions. The downregulation of REST may disrupt the homeostatic balance of astrocytes in DS.MethodsThis study aims to elucidate the role of REST in DS-astrocytes through comprehensive transcriptomic analysis and experimental validation.ResultsTranscriptomic analysis identified that REST-targeted differentially expressed genes (DEGs) in DS astrocytes are enriched in pathways associated with inflammatory response. Notably, our findings in astrocytes derived from DS human induced pluripotent stem cells (hiPSCs) show that the loss of nucleus REST leads to an upregulation of inflammatory mediators and markers indicative of the presence of reactive astrocytes. Lithium treatment, which restored nucleus REST in trisomic astrocytes, significantly suppressed the expression of these inflammatory mediators and reactive astrocyte markers.DiscussionThese findings suggest that REST is pivotal in modulating astrocyte functionality and reactivity in DS. The loss of REST in DS-astrocytes prompts the formation of reactive astrocytes, thereby compromising central nervous system homeostasis. Lithium treatment possesses the potential to rescue astrocyte reactivity in DS by restoring nucleus REST expression