Organoid microphysiological system preserves pancreatic islet function within 3D matrix

Three-dimensional (3D) multicellular organoids recapitulate the native complexities of human tissue better than traditional cellular monolayers. As organoids are insufficiently supported using standard static culture, microphysiological systems (MPSs) provide a key enabling technology to maintain organoid physiology in vitro. Here, a polydimethylsiloxane-free MPS that enables continuous dynamic culture and serial in situ multiparametric assessments was leveraged to culture organoids, specifically human and rodent pancreatic islets, within a 3D alginate hydrogel. Computational modeling predicted reduced hypoxic stress and improved insulin secretion compared to static culture. Experimental validation via serial, high-content, and noninvasive assessments quantitatively confirmed that the MPS platform retained organoid viability and functionality for at least 10 days, in stark contrast to the acute decline observed overnight under static conditions. Our findings demonstrate the importance of a dynamic in vitro microenvironment for the preservation of primary organoid function and the utility of this MPS for in situ multiparametric assessment.

Evaluating the use of whole genome sequencing for the investigation of a large mumps outbreak in Ontario, Canada

In 2017 Ontario experienced the largest mumps outbreak in the province in 8 years, at a time when multiple outbreaks were occurring across North America. Of 259 reported cases, 143 occurred in Toronto, primarily among young adults. Routine genotyping of the small hydrophobic gene indicated that the outbreak was due to mumps virus genotype G. We performed a retrospective study of whole genome sequencing of 26 mumps virus isolates from early in the outbreak, using a tiling amplicon method. Results indicated that two of the cases were genetically divergent, with the remaining 24 cases belonging to two major clades and one minor clade. Phylogeographic analysis confirmed circulation of virus from each clade between Toronto and other regions in Ontario. Comparison with other genotype G strains from North America suggested that the presence of co-circulating major clades may have been due to separate importation events from outbreaks in the United States. A transmission network analysis performed with the software program TransPhylo was compared with previously collected epidemiological data. The transmission tree correlated with known epidemiological links between nine patients and identified new potential clusters with no known epidemiological links.

3-D physiomimetic extracellular matrix hydrogels provide a supportive microenvironment for rodent and human islet culture

Organ-on-a-chip platforms serve as cost-efficient testbeds for screening pharmaceutical agents, mimicking natural physiology, and studying disease. In the field of diabetes, the development of an islet-on-a-chip platform would have broad implications in understanding disease pathology and discovering potential therapies. Islet microphysiological systems are limited, however, by their poor cell survival and function in culture. A key factor that has been implicated in this decline is the disruption of islet-matrix interactions following isolation. Herein, we sought to recapitulate the in vivo peri-islet niche using decellularized extracellular matrix (ECM) hydrogels. Sourcing from porcine bladder, lung, and pancreas tissues, 3-D ECM hydrogels were generated, characterized, and validated using both rodent and human pancreatic islets. Optimized decellularization protocols resulted in hydrogels with distinctive viscoelastic properties that correlated to their matrix composition. The in situ 3-D encapsulation of human or rat islets within ECM hydrogels resulted in improved functional stability over standard culture conditions. Islet composition and morphology were also altered, with enhanced retention of islet-resident endothelial cells and the formation of cord-like structures or sprouts emerging from the islet spheroid. These supportive 3-D physiomimetic ECM hydrogels can be leveraged within microfluidic platforms for the long-term culture of islets.

Lessons learnt from the Indian H1N1 (swine flu) epidemic: Predictors of outcome based on epidemiological and clinical profile

Introduction:

Influenza A (H1N1) virus has caused serious respiratory illness (swine flu) and death over the years. The first confirmed case of swine flu H1N1 in India was documented in May 2009, but huge numbers of cases were reported thereafter. In 2015, swine flu outbreak in India had led to significant morbidity and mortality.

Objective:

to study details of swine flu patients admitted in a rural tertiary care center in western India in 2015 and to identify predictors of mortality.

Methodology:

Retrospective data of swine flu cases admitted at a tertiary care teaching hospital in 2015 and their outcome as either cured or expired was recorded.

Result:

Out of 65 confirmed cases of severe swine flu that required hospitalization, 40(61%) were male. 55 of 65 (84.61%) patients [mean (SD) age: 50(15)] were cured while 10 patients [mean (SD) age 51(15)] expired. Overall mean (SD) age was 50.23(15) years with average (SD) days of hospitalization were 6.32(3.3) days. The commonest symptoms were cough (100%) followed by throat pain (96.9%), common-cold, fever (93.8%), and breathlessness (83.1%). 40% of patients needed non invasive ventilator support while 16.9% patient required invasive ventilator. Mean temperature on presentation was (99.96’F), RR (25.89/min), SpO2 on room air was 82.06%. Average White Blood Cells were 8274/mm³ with neutrophils were 79.58%. Mean procalcitonin was 0.83 ng/ml. It was found through univariate analysis that sputum production (P = 0.013), chest pain (P = 0.04), Respiratory Rate (P = 0.013), SpO2 on presentation at room air (P = 0.001), Days of non invasive ventilator (P = 0.001), intubation and invasive ventilator (P = 0.001) were statistically significantly associated with outcome but through multivariate analysis it was revealed that only requirement of intubation (invasive ventilator) was significantly predicting mortality(Odds ratio=234) (P = 0.0001).

Conclusion:

Requirement of intubation was associated with poor outcome.

Laundering of hospital staff uniforms at home

Few hospitals now launder staff uniforms. Staff are expected to use their own domestic machines, most of which run with 40 degrees C cycles. However, there is little information on the effectiveness of home laundering. This study demonstrates that domestic washing machines reduce viable counts of Staphylococcus aureus to below detectable levels from an inoculum of 10(8)-10(12) colony-forming units (>or=10(6)-fold reduction), even using low temperature (40 degrees C) programmes. Environmental organisms, predominantly Gram-negative flora, were introduced from the machine itself but were destroyed by tumble drying or ironing. Domestic laundering of uniforms is an acceptable alternative to hospital laundering if combined with tumble drying or ironing.

Fatal haemorrhage following a low-energy fracture of the pubic ramus

We report a case of fatal haemorrhage following a low-energy fracture of the pubic ramus in an 85-year-old woman.

Mathematical modeling of retinal birefringence scanning

Retinal birefringence scanning (RBS) is a new technique that is used to detect the fixation of the eye remotely and noninvasively. The method is based on analysis of polarization changes induced by the retina. In this study, the principles of RBS were mathematically modeled to facilitate a better understanding of the origins of the signals obtained. Stokes vector analysis and Mueller matrix multiplication were augmented with Poincaré sphere representation. The cornea was modeled as a linear retarder. The foveal area was modeled as a radially symmetric birefringent medium. The model accurately predicted the frequency and phase of RBS signals obtained during central and paracentral fixation. The signal that indicates central fixation during RBS likely results from a combination of the radial birefringence of the Henle fibers and the overlying corneal birefringence.

Automated detection of foveal fixation by use of retinal birefringence scanning

Foveal fixation was monitored in normal subjects remotely and continuously by use of a noninvasive retinal scan. Polarized infrared light was imaged onto the retina and scanned in a 3 degrees annulus at 44 Hz. Reflections were analyzed by differential polarization detection. In all 32 eyes studied, the detected signal was predominantly 88 Hz during central fixation (within +/-1 degree) and 44 Hz during paracentral fixation. Phase shift at 44 Hz correlated with the direction of eye displacement. Potential applications of this technique include screening for eye disease, eye position monitoring during clinical procedures, and use of eye fixation to operate devices.

Evidence for normal aging of the septo-hippocampal cholinergic system in apoE (-/-) mice but impaired clearance of axonal degeneration products following injury

The association of the epsilon4 allele of apoE with increased risk for Alzheimer's disease (AD) and with poor clinical outcome after certain acute brain injuries has sparked interest in the neurobiology of apoE. ApoE (-/-) mice provide a tool to investigate the role of apoE in the nervous system in vivo. Since integrity of the basal forebrain cholinergic system is severely compromised in AD, with severity of dysfunction correlating with apoE4 gene dosage, the present study tested the hypothesis that apoE is required to maintain the normal integrity of basal forebrain cholinergic neurons (BFCNs). Histological and biochemical analyses of the septo-hippocampal cholinergic system were performed in apoE (-/-) mice during aging and following injury. Using unbiased quantitative methods, there was little or no evidence for defects in the septo-hippocampal cholinergic system, as assessed by p75(NTR)-immunoreactive neuron number and size in the medial septum, cholinergic fiber density in the hippocampus, and choline acetyltransferase activity in the hippocampus, cortex, and striatum in aged apoE (-/-) mice (up to 24 months of age) as compared to age-matched wild-type mice of the same strain. In addition, cholinergic neuronal survival and size following fimbria-fornix transection in apoE (-/-) mice did not differ from controls. However, following entorhinal cortex lesion, there was persistence of degeneration products in the deafferented hippocampus in apoE (-/-) mice. These data suggest that although apoE is not required for the maintenance of BFCNs in vivo, it may play a role in the clearance of cholesterol-laden neurodegeneration products following brain injury.

Glial fibrillary acidic protein-apolipoprotein E (apoE) transgenic mice: astrocyte-specific expression and differing biological effects of astrocyte-secreted apoE3 and apoE4 lipoproteins

The epsilon4 allele of apolipoprotein E (apoE) is associated with increased risk for Alzheimer's disease (AD) and poor outcome after brain injury. In the CNS, apoE is expressed by glia, predominantly astrocytes. To define the potential biological functions of different human apoE isoforms produced within the brain, transgenic mice were generated in which human apoE3 and apoE4 expression is under control of the astrocyte-specific glial fibrillary acidic protein (GFAP) promoter. These animals were then bred back to apoE knock-out mice. Human apoE protein is found within astrocytes and the neuropil throughout development and into the adult period, as assessed by immunocytochemistry and immunoblot analysis in several GFAP-apoE3 and E4 lines. Cultured astrocytes from these mice secrete apoE3 and apoE4 in lipoproteins that are high-density lipoprotein-like in size. When primary hippocampal neurons are grown in the presence of astrocyte monolayers derived from these transgenic mice, there is significantly greater neurite outgrowth from neurons grown in the presence of apoE3-secreting astrocytes compared with apoE4-secreting or apoE knock-out astrocytes. These effects are not dependent on direct astrocyte-neuron contact and appear to require the low-density lipoprotein receptor-related protein. These data suggest that astrocyte-secreted, apoE3-containing lipoproteins have different biological effects than apoE4-containing lipoproteins. In addition to providing information regarding the role of astrocyte-secreted apoE lipoproteins in the normal brain, these animals will also be useful in models of both AD and CNS injury.

Spatial learning induces neurogenesis in the avian brain

It is known from previous work that neurones are born continuously in the ventricular zone of the bird brain. In this study, we show that the amount of cell proliferation in the ventricular zone of the hippocampus (HP) and the hyperstriatum ventrale (HV) is influenced by behavioural experience. Two groups of birds (marsh tits) were compared: those allowed to store and retrieve food once every 3 days between days 35 and 56, and age-matched controls treated in an identical way, except that they were not allowed to store and retrieve food. After three trials of storing and retrieval, between days 35 and 41 posthatch, experienced birds showed a significantly higher rate of cell proliferation than did controls. The experienced birds also showed a significant increase in total cell and neuronal number by day 56 posthatch, after eight trials of storing and retrieval. There were no significant differences in the amount of programmed cell death in the hippocampus in this study. In a novel analysis of the data we demonstrate that the effect of experience between days 35 and 41 was to increase the daily rate of neurogenesis in the ventricular zone from 3.9 to 10%, and that this change could account for the increase in total hippocampal neuronal number by day 56 in the experienced birds. Thus, the observed increase in hippocampal volume and neuronal number as a result of food storing and retrieval, may be caused by an increase in neurogenesis in the first few trials of food storing experience.

Hippocampal tissue transplants reverse lesion-induced spatial memory deficits in zebra finches (Taeniopygia guttata)

The avian hippocampal formation (Hf) plays an important role in spatial memory for food storing. Here we examined the effects of excitotoxic lesions of the Hf and subsequent neural transplantation on a one-trial associative memory task in zebra finches. The results showed (1) that small ibotenic acid lesions of the dorsal Hf of zebra finches produced significant spatial memory impairments compared with controls, sham-lesioned birds, and prelesion performance; and (2) that Hf-lesioned birds given transplants of embryonic hippocampal (H) tissue, but not those given transplants of embryonic anterior telencephalon (AT) tissue, showed a significant reversal of the performance deficits on the spatial memory task. Lesioned-only birds and lesioned birds given H or AT transplants that did not survive did not show behavioral improvement. Sham-lesioned and untreated control birds maintained good performance throughout the experiment. The H and AT transplants were found to be growing partially within the Hf and partially within the underlying ventricle. The transplants appeared healthy and contained neurons with beaded and unbeaded fibers (shown by immunohistochemistry with antibodies to parvalbumin, substance P, and a 200 kDa neurofilament protein). Blood vessels and erythrocytes were also present within the transplants. The results show that neural transplants can survive within the bird brain and that small lesions of the Hf produce significant spatial memory deficits that can only be reversed by surviving homologous H transplants, and not by heterologous telencephalon transplants.

Nerve growth factor effects on the song control system of zebra finches

The aim of this experiment was to test whether or not nerve growth factor (NGF) is involved in cholinergic processes in the avian brain, by injecting NGF into the higher vocal center (HVC) and examining its effects on adult male zebra finch song. Since NGF has been hypothesized to protect cells after injury, some birds received both NGF and ibotenic acid (IBO) lesions of HVC, while others received either NGF or IBO or neither (SHAM). Only the IBO-treated birds showed alterations in song. Although there was no evidence of cell preservation in the immunocytochemical and morphological analysis NGF appears to prevent the IBO induced impairment in song augmenting the activity of the remaining neurons and enhancing brain repair.

Automated analysis of electromyographic (EMG) recordings during botulinum injections

PURPOSE

Botulinum toxin is injected into extraocular muscles using electromyographic (EMG) guidance to confirm needle location prior to injection. The purpose of this study was to develop and test an automated, objective method of storing and grading EMG signal quality obtained during botulinum injection. A reliable, nonsubjective estimate of signal quality will enhance future studies of the complications or effectiveness of botulinum toxin injections into extraocular muscle.

METHODS

Injections were administered using a standard procedure. The EMG was digitized, recorded, and analyzed using discrete Fourier transform and power spectrum analysis. Audible signal quality was also graded subjectively by the surgeon. Patients were followed to determine the clinical response to the injection.

RESULTS

Eighteen patients (24 injections) were studied. Each sample was collected and analyzed in less than one second. The EMG contained signals over a range of frequencies from 50 to 500 Hz, with an average peak near 90 Hz. Substantial variability of the signal was observed between patients. Contracting muscle had a higher total power and peak frequency in most, but not all, cases. Total signal power correlated moderately with subjective estimates of signal quality. Neither subjective nor computer-derived signal quality estimates correlated with the response to injection or complications.

CONCLUSIONS

Computerized signal analysis can automatically characterize EMG signal power and frequency distribution. Although this technique has the potential to identify needle location at the time of botulinum injection accurately, signal variability limited the clinical and research utility of the present protocol.

Neuropathological sequelae of long-term allogeneic and syngeneic neural transplantation into the hippocampus

The long-term fate of multiple intrahippocampal allogeneic transplants of fetal basal forebrain tissue was studied in neonatally tolerised and immunised groups of rats with lesions of the fimbria-fornix. Despite the good survival of the allografts in all groups, unexpected transplant-associated host hippocampal neuropathology was discovered 12 months after transplantation, which consisted of (i) CA1 cell degeneration and (ii) abnormal accumulations of phosphorylated neurofilaments in neuronal perikarya and axonal swellings only within the host hippocampal neuropil and not of the transplanted tissue. This neurofilament abnormality, identified by RT97 immunohistochemistry, was significantly greater in the transplanted rats compared to the non-grafted lesion-only and sham-lesioned rats (p < 0.01). The same type of neurofilament abnormality was again observed in a second, separate experiment using unilateral and bilateral syngeneic and allogeneic transplants. The neuropathology was significantly (p < 0.05) greater in the transplanted side of the unilateral transplanted rats compared to the non-transplanted lesion-only control side of the same animals, showing that transplantation per se was a major factor involved in the pathogenesis of this neuropathology, irrespective of the type of transplant (syngeneic or allogeneic). In addition, a small degree of neurofilament abnormality was also found within the transplants in the second experiment, but not in the first. The results show that, under certain conditions, specific local neuropathological damage to the surrounding host neural tissue can develop in long-surviving allografted and syngrafted animals.

Immunoidentification of cellular brain proteins associated with cognitive recovery in brain transplants

In adult, lesion-impaired rat brain receiving embryonic day 15 (E15) fetal transplants, the level of expression of glial fibrillary acidic protein (GFAP) correlates positively with choline acetyltransferase (ChAT) levels and also with measurements of successful behavioural recovery. These results suggest that glial cells may play a pivotal role in the cognitive success of so-called cholinergic-rich transplants. The objective of this study was to investigate the association between GFAP- and ChAT-staining antigens in or around cholinergic-rich fetal grafts transplanted in adult cortex. An immunohistochemical fluorescent double-labelling technique was used to simultaneously identify GFAP- and ChAT-staining cells to assess whether there was a different type or distribution of cells present in these successful transplants. On brain sections of transplant area, GFAP-staining glial cells did not co-label with ChAT-staining cells. The transplant area, therefore, did not reveal a different type of cell from those seen in comparable normal cortical brain but rather a greater concentration of both GFAP- and ChAT-positive staining cells.

Neural transplantation: problems and prospects for therapeutic application

Successful demonstrations of behavioural recovery in a variety of lesion and mutant animal models have encouraged the application of neural transplantation to the alleviation of neurodegenerative disease. Apart from the continuing shortage of foetal tissue, the major problems to be resolved for successful application of neural transplantation to humans are: first, immune rejection of allograft tissue and its pathological consequences to both graft and host tissue; and second, the establishment of normal and extensive graft-host connectivity. Recent developments in transplant research are beginning successfully to apply a number of strategies to resolve these problems.

Localization of GABA-like immunoreactivity in the ectostriatum of domestic chicks: GABA immunocytochemistry combined with Golgi impregnation

The distribution of GABA-like immunoreactivity (GABA-LI) in the ectostriatal core (Ec) of domestic chicks (one to two days old) was investigated using (1) preembedding GABA immunocytochemistry and (2) Golgi impregnation and gold-toning combined with postembedding GABA immunocytochemistry. Two major classes of neurons which display GABA-LI were identified in chick Ec. Firstly, large GABA immunopositive cells which comprise at least two further subtypes: an ovoid or polygonal form of 14-18 microns diameter with no apparent polarity of dendrites and a smaller cell (10-14 microns) with ovoid or basket-shaped soma and often more polarized dendritic ramification. In both subtypes the dendritic surface is smooth or sparsely spiny. Secondly, a small GABA immunopositive cell which is characterized by a round cell body of 5-8 microns diameter and thin and sparsely ramifying dendrites of smooth surface or with irregular protrusions. Based upon comprehensive descriptions of ectostriatal cytoarchitectonics (Tömböl et al., 1988c), and synaptology (Watanabe et al., 1985), we argue that the GABA-immunopositive cell types of chick Ec are likely to represent inhibitory interneurons comparable with GABAergic inhibitory cell types described in mammalian visual cortex.

Training induced dendritic spine density changes are specifically related to memory formation processes in the chick, Gallus domesticus

The density of dendritic spines on large, multipolar, projection neurons in the intermediate medial hyperstriatum ventrale (IMHV) of 1-day-old chicks was examined after training on a one-trial passive avoidance task. Chicks trained on the task were given a brief, subconvulsive transcranial electroshock 5 min after training, a procedure which rendered about half of them amnesic. The spine density was found to be significantly higher 24-26 h after training in the left IMHV in chicks that remembered the response compared to chicks rendered amnesic. These data, taken together with our earlier observations on spine density changes following training, argue strongly in favour of a specific role for dendritic spines in memory formation in the chick.

Changes in the number and structure of dendritic spines 25 hours after passive avoidance training in the domestic chick, Gallus domesticus

One-day-old chicks spontaneously peck at a shiny chrome bead. If the bead is coated with methylanthranilate, a bitter tasting substance (M-chicks), they peck once and avoid a similar bead subsequently. Control chicks peck, and continue pecking at a bead dipped in water (W-chicks). Twenty-five hours after this one-trial passive avoidance training the brains were fixed and Golgi-impregnated. A class of large, multipolar, projection neurons from the intermediate medial hyperstriatum ventrale (IMHV) of both hemispheres from M- and W-chicks were examined for changes in their spine density and spine shape. An estimate of the true spine number was obtained using the correction formula of Feldman and Peters. M-chicks showed highly significant increases (P less than 0.0001) in spine density of between 89-113% in the left hemisphere, and 37-69% in the right, compared with W-chicks. There was a significant hemispheric asymmetry in W-chicks: the right hemisphere had approximately 47% more spines per micron than the left, and this difference was abolished after training. Following passive avoidance training, significant increases in spine head diameter (by approximately 9%) and decreases in spine stem length (by approximately 17%), with no significant alterations in overall spine length, were observed in the left hemisphere. The mean dendrite lengths were not significantly changed after training, but an asymmetry of this measure in W-chicks (left greater than right) was present in dendrite orders 2 (P less than 0.01) and 3 (P less than 0.02). These results show that spine densities can increase rapidly (within 25 h) following a one-trial passive avoidance training task and that spine shape changes can be found on the same dendrites which also show changes in spine number. The data support the view that dendritic spines are involved in memory formation processes.