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result(s) for
"Mount, Richard"
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Loss of Fat4 disrupts PCP signaling and oriented cell division and leads to cystic kidney disease
by
Mount, Richard
,
Saburi, Sakura
,
McNeill, Helen
in
Agriculture
,
Animal Genetics and Genomics
,
Animals
2008
Helen McNeill and colleagues show that loss of Fat4, a homolog of the
Drosophila
planar cell polarity protein Fat, disrupts oriented cell division, leading to a failure of tubule elongation and cystic kidney disease in mice. The findings suggest that loss of planar cell polarity may underlie some forms of cystic kidney disease in humans.
Tissue organization in
Drosophila
is regulated by the core planar cell polarity (PCP) proteins Frizzled, Dishevelled, Prickle, Van Gogh and Flamingo. Core PCP proteins are conserved in mammals and function in mammalian tissue organization. Recent studies have identified another group of
Drosophila
PCP proteins, consisting of the protocadherins Fat and Dachsous (Ds) and the transmembrane protein Four-jointed (Fj). In
Drosophila
, Fat represses
fj
transcription, and Ds represses Fat activity in PCP. Here we show that
Fat4
is an essential gene that has a key role in vertebrate PCP. Loss of
Fat4
disrupts oriented cell divisions and tubule elongation during kidney development, leading to cystic kidney disease.
Fat4
genetically interacts with the PCP genes
Vangl2
and
Fjx1
in cyst formation. In addition,
Fat4
represses
Fjx1
expression, indicating that Fat signaling is conserved. Together, these data suggest that
Fat4
regulates vertebrate PCP and that loss of PCP signaling may underlie some cystic diseases in humans.
Journal Article
A generalised ecohydrological landscape classification for assessing ecosystem risk in Australia due to an altering water regime
by
O'Grady, Anthony P.
,
Post, David A.
,
Pavey, Chris R.
in
Aquatic resources
,
Classification
,
Coal
2024
Describing and classifying a landscape for environmental impact and risk assessment purposes is a non-trivial challenge because this requires region-specific landscape classifications that cater for region-specific impacts. Assessing impacts on ecosystems from the extraction of water resources across large regions requires a causal link between landscape features and their water requirements. We present the rationale and implementation of an ecohydrological classification for regions where coal mine and coal seam gas developments may impact on water. Our classification provides the essential framework for modelling the potential impact of hydrological changes from future coal resource developments at the landscape level. We develop an attribute-based system that provides representations of the ecohydrological entities and their connection to landscape features and make use of existing broad-level classification schemes into an attribute-based system. We incorporate a rule set with prioritisation, which underpins risk modelling and makes the scheme resource efficient, where spatial landscape or ecosystem classification schemes, developed for other purposes, already exist. A consistent rule set and conceptualised landscape processes and functions allow for the combination of diverse data with existing classification schemes. This makes the classification transparent, repeatable and adjustable, should new data become available. We apply the approach in three geographically different regions, with widely disparate information sources, for the classification, and provide a detailed example of its application. We propose that it is widely applicable around the world for linking ecohydrology to environmental impacts.
Journal Article
Australian vegetated coastal ecosystems as global hotspots for climate change mitigation
2019
Policies aiming to preserve vegetated coastal ecosystems (VCE; tidal marshes, mangroves and seagrasses) to mitigate greenhouse gas emissions require national assessments of blue carbon resources. Here, we present organic carbon (C) storage in VCE across Australian climate regions and estimate potential annual CO
2
emission benefits of VCE conservation and restoration. Australia contributes 5–11% of the C stored in VCE globally (70–185 Tg C in aboveground biomass, and 1,055–1,540 Tg C in the upper 1 m of soils). Potential CO
2
emissions from current VCE losses are estimated at 2.1–3.1 Tg CO
2
-e yr
-1
, increasing annual CO
2
emissions from land use change in Australia by 12–21%. This assessment, the most comprehensive for any nation to-date, demonstrates the potential of conservation and restoration of VCE to underpin national policy development for reducing greenhouse gas emissions.
Policies aiming to preserve vegetated coastal ecosystems (VCE) to mitigate greenhouse gas emissions require national assessments of blue carbon resources. Here the authors assessed organic carbon storage in VCE across Australian and the potential annual CO
2
emission benefits of VCE conservation and find that Australia contributes substantially the carbon stored in VCE globally.
Journal Article
Three Distinct Auditory Areas of Cortex (AI, AII, and AAF) Defined by Optical Imaging of Intrinsic Signals
by
Mori, Naoki
,
Sawada, Soichi
,
Harrison, Robert V.
in
Animals
,
Audiometry, Pure-Tone
,
auditory cortex
2000
Using pure-tone sound stimulation, three separate auditory areas are revealed by optical imaging of intrinsic signals in the temporal cortex of the chinchilla (Chinchilla laniger). These areas correlate with primary auditory cortex (AI) and two secondary areas, AII and the anterior auditory field (AAF). We have distinguished AI on the basis of concurrent single-unit electrophysiological recording; neurons within the AI intrinsic signal region have short (<15 ms) onset–response latencies compared with neurons recorded in AII and the AAF. Within AI, AII, and AAF we have been able to define cochleotopic or tonotopic organization from the differences in intrinsic signal areas evoked by pure tones at octave-spaced frequencies from 500 Hz to 16 kHz. The maps in AI and AII are arranged orthogonal to each other.
Journal Article
Influence of Age at Implantation and of Residual Hearing on Speech Outcome Measures after Cochlear Implantation: Binary Partitioning Analysis
by
Harrison, Robert V.
,
El-Hakim, Hamdy
,
Papsin, Blake C.
in
Audiometry
,
Children
,
Diagnostic Tests
2002
The goal of this study was to evaluate speech understanding outcomes in prelingually deaf children who use a cochlear implant device. Specifically, we discuss investigations on 2 prognostic variables — age at implantation and degree of residual hearing — and use a novel method: binary partitioning analysis. Our outcome measures are standard speech perception evaluations, including the Word Intelligibility by Picture Identification (WIPI) test, the Phonetically Balanced–Kindergarten (PBK) test, and the Glendonald Auditory Screening Procedure (GASP). Regarding age at implantation, we definitely showed that growth rates of speech understanding do relate to age at implantation, but not in a simple fashion. We used binary partitioning in an attempt to find the age at implantation that best separates the performances of children with younger versus older ages at implantation. We found that there is no one “critical age”; much appears to depend on the nature and difficulty (eg, whether open- or closed-set) of the test used. Regarding residual hearing, binary partitioning analysis was unable to show that the amount of residual hearing (as shown by preimplantation audiometric data) has any significant bearing on speech outcome measures in congenitally or prelingually deaf children.
Journal Article
Is wind-wave fetch exposure related to soft shoreline change in swell-sheltered situations with low terrestrial sediment input?
2015
Rising sea levels and changing wind climates are widely expected to be associated with receding coastlines, creating a planning need for coastal change prediction, especially for soft shores like those associated with saltmarsh. We ask whether it is possible use a simple cartographic wind-wave fetch method to estimate the spatial pattern of progradation and recession of soft shores in swell-sheltered situations in which there is little or no input of new sediment from terrestrial sources. For points on an extensive embayment shoreline of this type we mapped change over 54 years from aerial photographs, recorded current shoreline morphology and calculated a wave fetch index (WFI). Morphological indication of strong progradation was associated with low WFI, but there was no statistically significant effect of variation in WFI on the degree of shoreline retreat. Saltmarsh shorelines averaged 14 cm per annum retreat between 1952 and 2006, a rate that did not vary significantly between air photo periods. We conclude that our geographic information system approach utilising WFI is likely to be useful as a planning tool in identifying those parts of sediment-poor saltmarsh shores where erosion is most likely or least likely to occur, but not particularly useful for predicting finer-scale variation in rates of shoreline recession within the particular substrate types in our study area. In the context of relative sea-level rise and increasing wind speeds, such modelling can help identify coastlines which are likely to support saltmarshes into the future.
Journal Article
Miracles of Our Lady
by
Cash, Annette Grant
,
Berceo, Gonzalo de, 13th cent
,
Mount, Richard Terry
in
Blessed Virgin, Saint
,
Mary
,
Mary, Blessed Virgin, Saint -- Poetry
1997
Miracle tales, in which people are rewarded for piety or punished for sin through the intervention of the Virgin Mary, were a popular literary form all through the Middle Ages.
Optical Imaging of Intrinsic Signals in Chinchilla Auditory Cortex
by
Harrison, Robert V.
,
Harel, Noam
,
Raveh, Eyal
in
Animals
,
Auditory Cortex - physiology
,
Auditory Perception - physiology
1998
We have assessed sound frequency and intensity responses in primary auditory cortex of the (ketamine) anesthetized chinchilla using optical imaging of intrinsic signals. Temporal cortex was exposed via a 10-mm craniotomy and a windowed chamber was mounted. A 4-second period of gated tones (10 ms rise/fall; 50 ms plateau; 10/s) was presented to the contralateral ear at levels between 0 and 80 dB SPL. The cortical surface was illuminated with 540 nm light and video images captured in 0.5-second bins for 7.5 s (Imager 2001; Optical Imaging). Intrinsic signals were first apparent 0.5–1 s after stimulus onset, and were maximal after 3–4 s; they decayed over several seconds. The cortical area in which intrinsic activity was detected corresponded closely with electrophysiologically defined AI cortex. Intrinsic signals can reliably be detected to stimuli at 30–40 dB SPL, and in general, the area of intrinsic signal activity tends to expand with increasing stimulation level. Using stimulation levels of 80 dB SPL, we show that low-frequency stimuli (0.5–1 kHz) evoke intrinsic signals in anterior areas whilst posterior areas are activated by high-frequency stimuli (e.g. 16 kHz). Thus a low- to high-frequency tonotopic organization is seen along this axis.
Journal Article
Basal Cochlear Lesions Result in Increased Amplitude of Otoacoustic Emissions
by
Harrison, Robert V.
,
Hirakawa, Haruo
,
Harel, Noam
in
Amikacin - pharmacology
,
Amikacin - poisoning
,
Animals
1998
We have measured the changes in transient otoacoustic emissions (TEOAEs) and distortion product otoacoustic emissions (DPOAEs) during and after ototoxic amikacin treatment in an animal (chinchilla) model. TEOAE and DPOAE were recorded from 6 adult chinchillas over a 6-week time course starting just before a 5-day or 7-day treatment period with amikacin sulphate (400 mg/kg/day, i.m.). After final recordings, cochlear morphology was assessed by scanning electron microscopy. Generally, both DPOAE and TEOAE amplitudes change during and after treatment in a systematic fashion. High-frequency components change first, followed by lower-frequency components. We note that there is often a long latency to the onset of changes in otoacoustic emissions (OAE), and that these changes can continue for weeks after treatment. Most importantly we report that when the basal region of the cochlea is damaged in the frequency region above the OAE recording bandwidth (0.6–6 kHz for TEOAE; 1–6.7 kHz for DPOAE), we often find an increase in OAE amplitudes. More specifically, we note that as a cochlear lesion progresses apically, there is often a transient increase in a frequency-specific OAE before it reduces or is lost. Our results suggest that the increase in OAE amplitudes precedes the expression of detectable cochlear pathology.
Journal Article
Tonotopic mapping in auditory cortex of the adult chinchilla with amikacin-induced cochlear lesions
by
Harel, N
,
Harrison, R V
,
Hirakawa, H
in
Amikacin - adverse effects
,
Animals
,
Anti-Bacterial Agents - adverse effects
2000
We have found a reorganization of tonotopic maps (based on neuron response thresholds) in primary auditory cortex of the adult chinchilla after amikacin-induced basal cochlear lesions. We find an over-representation of a frequency that corresponds to the border area of the cochlear lesion. The reorganization observed is similar in extent to that previously seen in a developmental model. The properties of neurons within the over-represented area were investigated in order to determine whether their responses originated from a common input (an indication of true plasticity) or represented only the result of truncating the activity of the sensory epithelium (\"pseudo-plasticity\"). Some aspects of our data fit with a true plasticity model and indicate the potential for the deafferented cortex of the mature cortex to regain connections with the surviving sensory epithelium.
Journal Article