Body composition in underweight elderly subjects: reliability of bioelectrical impedance analysis

BACKGROUND AND AIMS: In underweight elderly subjects it is important to estimate body composition and particularly fat-free mass (FFM). Bioelectrical impedance analysis (BIA) is a non-invasive method in determining FFM, but its usefulness in these frail subjects should be verified. The aim of this study is to verify in underweight elderly people the reliability of previously published BIA formulas in detecting FFM. METHODS: Fifty-seven hospitalized elderly subjects (27 males and 30 females) with body mass index <20 kg/m(2) were selected. In all subjects, FFM was detected by dual energy X-ray absorptiometry. Moreover, BIA measurements were performed at standard frequency (50 kHz and 800 microA) and FFM was derived using the main previous published BIA equations. Results: In men, Kyle and Rising equations gave acceptable estimates of FFM with a mean error, respectively, of 1+/-1.9 and 1.4+/-1.7 kg. Also RJL formula could be used after adjusting for a correction factor. In women, no equation seemed sufficiently reliable to estimate FFM. CONCLUSIONS: BIA method seems useful to evaluate body composition in underweight elderly men but it seems to have intrinsic limits in women. Nevertheless, the variability in behavior of the different equations suggests to be careful in adopting BIA equations.     

Auditory and vestibular findings in Fabry disease: a study of hemizygous males and heterozygous females

AIM: This study aimed to evaluate audiological and vestibular involvement in Fabry disease and the early effects of enzyme replacement therapy with human alpha-galactosidase A. METHODS: Fourteen patients (10 males, 4 females) aged 14-57 years were studied. Each patient underwent a clinical (history of otological and vestibular aspects, otoscopy) and instrumental (pure tone and speech audiometry, impedance, auditory brainstem response and oto-acoustic emission recordings, vestibular caloric tests, electronystagmography during acceleratory stimulation, dynamic posturography) evaluation before starting enzyme replacement therapy. RESULTS: Fifty per cent of patients complained of hearing symptoms (hearing loss, tinnitus, ear fullness). Subjective hearing loss was present in six cases and in three cases it was the first reported symptom of Fabry disease. In six of the seven cases the onset and/or progression of hearing symptoms were sudden. Vertigo or dizziness was reported by four patients and in two cases was associated with hearing symptoms. Audiological evaluation showed sensorineural hearing loss in eight patients (5 males, 3 females). Hearing loss was unilateral in six cases and bilateral in the remaining two cases. The hearing loss (HL) ranged from 30 to 80 dB HL (mean, 43 dB HL) and the lesion was always cochlear. Vestibular examination showed abnormalities in four patients (bilateral weak/abolished response in three cases, side prevalence in one case), which were not related to either the audiological results or the history of vertigo/dizziness. CONCLUSION: Involvement of the inner ear is common in men and women with Fabry disease. We found a high incidence of cochlear hearing loss, which was typically unilateral and showed onset and/or progression by sudden episodes. Vascular or hydropic mechanisms could be hypothesized to explain audiological findings. Vestibular involvement had a lower incidence and showed a different pattern, thus suggesting that several pathophysiological mechanisms could play a role in determining inner ear damage in Fabry disease. Our preliminary results show that enzyme replacement therapy may stabilize hearing function; however, further follow-up is required.     

Molecular pathology and genetics of congenital hepatorenal fibrocystic syndromes

The hepatorenal fibrocystic (HRFC) syndromes are a heterogeneous group of severe monogenic conditions that may be detected before birth. Commonly, HRFC syndromes present in the neonatal and paediatric age, with consistent developmental abnormalities mostly involving the liver and kidney. The changes include the proliferation and dilatation of epithelial ducts in these tissues with abnormal deposition of extracellular matrix. In this review, we examine the clinical features and differential diagnoses of this group of syndromes, including autosomal recessive polycystic kidney disease (ARPKD), juvenile nephronophthisis (NPHP), Meckel-Gruber syndrome (MKS), Bardet-Biedl syndrome (BBS), and Jeune asphyxiating thoracic dystrophy (JATD). Extrahepatic manifestations include mostly bone and central nervous system abnormalities, dysmorphic features, and developmental delay. Previously, it has been suggested that ARPKD, JATD, and Ellis-van Creveld syndrome (EvC) may arise from defects in differentiation in a common developmental pathway. We review recent molecular advances in the recessive HRFC syndromes and discuss this hypothesis.     

Contrasting effects of organic and inorganic toxicants on freshwater periphyton

This study analyses the factors influencing the response of periphyton communities to toxicants in order to test the validity of the short-term physiological method. The effects of two model compounds, atrazine and zinc, on the photosynthesis of periphyton from different lotic systems were analyzed using short-term toxicity tests. Periphyton communities from seven sites belonging to a relatively small area were used to explore the ecological parameters affecting toxicity in flowing waters. Furthermore, time course studies of zinc toxicity on intact and suspended periphyton were carried out in order to evaluate the significance of periphyton structure (thickness) on toxicity. Atrazine toxicity varied slightly (0.42-2.42 microM) in tests with photosynthesis as an endpoint. Only environmental light was detected to lead to systematic changes in sensitivity of field collected communities. In contrast, the range of EC(10) values for zinc was very broad (7->1000 microM), and mainly related to algal biomass, while also water chemistry (alkalinity) was important. The results of time-course experiments indicated that the penetration of zinc into thick biofilms was limited. The model compounds tested in the present study may exemplify two different situations. In the case of atrazine, the effect on periphyton is easy to predict from the physiological tests used here. On the other hand, zinc toxicity assessed using photosynthesis of periphyton is much affected by many biological and chemical variables. It is concluded that toxicity tests of metals and other organic and inorganic compounds should be based on longer times of exposure.     

The effect of copper exposure on a simple aquatic food chain

The effect of copper (44 microg l(-1)) on a simple food chain was studied using indoor experimental channels to identify the changes in periphyton community (metabolism, chlorophyll a content, abundance, composition and lipid and protein content) and in herbivore (Stagnicola vulnerata) growth rate and reproduction. The algal community was sensitive to copper at the beginning but differences between treatments were not significant during the experiment. However, copper affected growth rate, reproduction and embryo hatching on snails. These results indicate that the effects on snails are more sensitive endpoints in assessing sublethal copper toxicity than effects on periphyton.     

Molecular mechanisms and therapeutical implications of intramembrane receptor/receptor interactions among heptahelical receptors with examples from the striatopallidal GABA neurons

The molecular basis for the known intramembrane receptor/receptor interactions among G protein-coupled receptors was postulated to be heteromerization based on receptor subtype-specific interactions between different types of receptor homomers. The discovery of GABAB heterodimers started this field rapidly followed by the discovery of heteromerization among isoreceptors of several G protein-coupled receptors such as delta/kappa opioid receptors. Heteromerization was also discovered among distinct types of G protein-coupled receptors with the initial demonstration of somatostatin SSTR5/dopamine D2 and adenosine A1/dopamine D1 heteromeric receptor complexes. The functional meaning of these heteromeric complexes is to achieve direct or indirect (via adapter proteins) intramembrane receptor/receptor interactions in the complex. G protein-coupled receptors also form heteromeric complexes involving direct interactions with ion channel receptors, the best example being the GABAA/dopamine D5 receptor heteromerization, as well as with receptor tyrosine kinases and with receptor activity modulating proteins. As an example, adenosine, dopamine, and glutamate metabotropic receptor/receptor interactions in the striatopallidal GABA neurons are discussed as well as their relevance for Parkinson's disease, schizophrenia, and drug dependence. The heterodimer is only one type of heteromeric complex, and the evidence is equally compatible with the existence of higher order heteromeric complexes, where also adapter proteins such as homer proteins and scaffolding proteins can exist. These complexes may assist in the process of linking G protein-coupled receptors and ion channel receptors together in a receptor mosaic that may have special integrative value and may constitute the molecular basis for some forms of learning and memory.     

Social perception and early visual processing in schizophrenia

Persons with schizophrenia experience deficits in social cognition-the cognitive processes involved in how people perceive and interpret information about themselves, others, and social situations. These deficits may be related to the neurocognitive impairments often experienced by persons with schizophrenia. Our primary objective was to examine associations between social perception and early visual processing in schizophrenia. Our secondary objective was to examine whether outpatients with schizophrenia and healthy persons differ in social perception. Forty outpatients with schizophrenia and 30 healthy persons completed a measure of social perception (the Half-Profile of Nonverbal Sensitivity), visual masking procedures, and ratings of positive and negative symptoms. Within patients, performance on visual masking procedures was related to performance on the Half-Profile of Nonverbal Sensitivity. Patients with schizophrenia and the healthy persons differed significantly in their performance on the Half-Profile of Nonverbal Sensitivity, but this difference became nonsignificant when education was a covariate. These findings suggest that social perception in schizophrenia is related to very early aspects of visual processing.     

Protective effects of alpha-tocopherol against gentamicin-induced Oto-vestibulo toxicity: an experimental study

OBJECTIVE: Free radicals are involved in gentamicin ototoxicity and vestibular dysfunction and it has been demonstrated that free radical scavengers, such as alpha-tocopherol, are able to inactive free radicals, attenuating tissue damage This study was designed to investigate the possible protective effects of alpha-tocopherol against gentamicin-induced oto-vestibulo toxicity. MATERIAL AND METHODS: Adult albino guinea pigs were divided into four groups and were treated for 2 weeks as follows: Group A, controls; Group B, gentamicin plus corn oil; Group C, gentamicin only; and Group D, gentamicin plus alpha-tocopherol. To evaluate vestibular function, the animals underwent sinusoidal oscillations in the dark about their vertical and longitudinal axes to evoke horizontal and vertical vestibulo-ocular reflexes (VORs), respectively. Electrocochleographic recordings were performed using an implanted round window electrode. The compound action potentials (CAPs) at 2, 4, 8 and 16 kHz were measured every 5 days Morphological changes were analysed by means of scanning electron microscopy. RESULTS: Gentamicin induced a consistent reduction in VOR responses and a progressive high-frequency hearing loss of 50-60 dB sound pressure level. Alpha-Tocopherol co-therapy slowed the progression of hearing loss and significantly attenuated the final threshold shifts The impairment of vestibular function was reduced, as evidenced by an increased VOR gain. The massive loss of outer hair cells in the cochlear basal turn and of cristae ampullaris stereocilia in gentamicin-treated animals was not observed in the cochlea of animals protected with alpha-tocopherol. CONCLUSION: This study supports the hypothesis that alpha-tocopherol interferes with gentamicin-induced free radical formation, and suggests that this drug may be useful in preventing aminoglycoside oto-vestibulo toxicity.