Falls risk assessment outcomes and factors associated with falls for older Indigenous Australians

Objective: To describe the prevalence of falls and associated risk factors in older Indigenous Australians, and compare the accuracy of validated falls risk screening and assessment tools in this population in classifying fall status. Method: Cross‐sectional study of 289 Indigenous Australians aged ≥45 years from the Kimberley region of Western Australia who had a detailed assessment including self‐reported falls in the past year (n=289), the adapted Elderly Falls Screening Tool (EFST; n=255), and the Falls Risk for Older People‐Community (FROP‐Com) screening tool (3 items, n=74) and FROP‐Com falls assessment tool (n=74). Results: 32% of participants had ≥1 fall in the preceding year, and 37.3% were classified high falls risk using the EFST (cut‐off ≥2). In contrast, for the 74 participants assessed with the FROP‐Com, only 14.9% were rated high risk, 35.8% moderate risk, and 49.3% low risk. The FROP‐Com screen and assessment tools had the highest classification accuracy for identifying fallers in the preceding year (area under curve >0.85), with sensitivity/specificity highest for the FROP‐Com assessment (cut‐off ≥12), sensitivity=0.84 and specificity=0.73. Conclusions: Falls are common in older Indigenous Australians. The FROP‐Com falls risk assessment tool appears useful in this population, and this research suggests changes that may improve its utility further.     

How ultrasound influences the electrodeposition of metals

The mechanism of deposition of zinc, lead, cobalt and mercury on glassy carbon has been studied under the influence of power ultrasound (20 kHz), using cyclic voltammetry. Systems of relatively high metal concentration (1 M) and low concentration (10 mM) were compared, and the effects of the application of different ultrasonic intensities, from silent conditions to 238 W cm^?2 investigated. Ultrasound was found to have a significant effect on the deposition part of the cycle in systems in which deposition is under diffusion control, while little, if any, effect was observed on systems in which deposition is under interfacial/charge transfer control. Ultrasound also affected the size of the stripping peak relative to the deposition peak, with the precise effect dependent on the deposition mechanism of the system. At high intensities, the ablative power of ultrasound was observed.     

Autoradiographic characterization of I-neurotensin binding sites in human entorhinal cortex

The laminar and rostro—caudal distribution of ¹²⁵I-neurotensin binding sites is described in human entorhinal cortex using quantitative autoradiography. Specific binding was most prominent over the cell clusters of layer II of the entorhinal cortex throughout its rostro-caudal extent. Dense binding was also observed in the adjacent presubiculum and cortical amygdaloid transition area, whereas minimal binding was detected in the hippocampus and dentate gyms. ¹²⁵I-Neurotensin may serve as a selective probe for neurotensin receptor alterations and layer II-specific cytoarchitectural disturbances in the entorhinal cortex in neuropsychiatric diseases associated with abnormalities of the mesial temporal lobe.     

Rapid increase in mitochondrial volume in nucleus magnocellularis neurons following cochlea removal

Second-order auditory neurons in nucleus magnocellularis (NM) of the chick brainstem undergo a series of rapid metabolic changes following unilateral cochlea removal, culminating in the death of 25% of NM neurons. Within hours of cochlea removal, ipsilateral NM neurons show marked increases in histochemical staining for the mitochondrial enzymes succinate dehydrogenase and cytochrome oxidase. We investigated corresponding ultrastructural changes in NM neurons by preparing animals undergoing unilateral cochlea removal for transmission electron microscopy. We quantified changes in NM mitochondrial volume by stereological methods and qualitatively compared mitochondrial morphology between NM neurons destined to survive and those destined to die after cochlea removal. Within hours of cochlea removal, ipsilateral NM neurons show striking increases in mitochondrial volume (84% at 12 hours and 236% at 12 hours after cochlea removal compared to unoperated, control animals). At 2 week survival times, ipsilateral NM neurons contain fewer mitochondria than contralateral neurons. Surprisingly, anesthesia alone causes short-term increases in NM mitochondrial volume. Animals anesthetized with pentobarbital and ketamine and sacrificed 6 or 12 hours later showed a 45% increase in mitochondrial volume compared to previously unanesthetized animals. NM neurons destined to die within days of cochlea removal can be identified within several hours after deafferentation by the appearance of their ribosomes. We observed qualitative differences in mitochondrial morphology in dying neurons. Mitochondria in neurons destined to die consistently showed mitochondrial swelling and vacuolization indicative of metabolic dysfunction. Similar mitochondrial changes have been reported when mitochondria take up excess calcium. Ultrastructural changes in NM after cochlea removal display features of both programmed and pathological cell death, in which increased intracellular calcium is thought to play a role. © 1994 Wiley-Liss, Inc.     

Energy coupling to periplasmic binding protein-dependent transport systems: stoichiometry of ATP hydrolysis during transport in vivo.

Periplasmic binding protein-dependent transport systems mediate the accumulation of many diverse substrates in prokaryotic cells. Similar transport systems, including the P-glycoprotein responsible for multidrug resistance in human tumors, are also found in eukaryotes. The mechanism by which energy is coupled to the accumulation of substrate by these transport systems has been controversial. In this paper we demonstrate that ATP hydrolysis occurs in vivo concomitantly with transport. These data strongly suggest that ATP hydrolysis directly energizes substrate accumulation by these transport systems. The apparent stoichiometry is one to two molecules of ATP hydrolyzed per molecule of substrate transported.