Associations between body composition, physical capabilities and pulmonary function in healthy older adults.

BACKGROUND/OBJECTIVES: There are positive associations between pulmonary function (PF) and fat-free mass as well as muscle strength. Contrarily, negative associations were found with indirect measures of visceral adipose tissue (VAT). We aimed to differentiate between associations of body composition and PF by assessing mediating and moderating effects of physical capabilities. SUBJECTS/METHODS: Cross-sectional data were assessed among 40 healthy, free-living elderly (20 males) aged 65.1-81.2 years (mean±s.d. age: 72.2±4.3 years; body mass index: 25.6±3.7 kg/m2). Total and regional skeletal muscle (SM), and adipose tissue (AT) were measured using whole-body magnetic resonance imaging. Muscle strength by handgrip dynamometry, physical activity (PA) by questionnaire, and physical performance by gait speed and sit-to-stand test (STS). Forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1) were assessed by spirometry. RESULTS: Positive associations between height-standardized FVC (FVCI) as well as FEV1 (FEVI), and SM (r=0.435-0.520, P<0.05) were found; subcutaneous AT (SAT) and FVCI correlated negatively (r=-0.374; P<0.05). HGS and PA correlated positively with FEVI (r=0.456-0.608, P<0.05), HGS also with FVCI (r=0.595, P<0.05). Stepwise multiple regression using FVCI and FEVI as dependent variables, and total/thoracic SM, VAT, SAT, HGS, PA and physical performance as independent variables showed that (i) only HGS entered the regression for predicting FVCI (R2=0.351; standard error of estimation (SEE)=0.32 l), and (ii) HGS and PA explained 50% of FEVI (SEE=0.23 l). HGS mediated the relationship between SM and PF; the STS moderated the relationship between SM and FVCI. CONCLUSIONS: In healthy elderly, PF is positively associated with SM; physical capabilities mediate and moderate these relationships.

Investigations of the partitioning and residence times of Po-210 and Pb-210 in a riverine system in Southeast Michigan, USA.

Some of the daughter products in the (222)Rn-decay series, such as (210)Po and (210)Pb, have been widely used as tracers and chronometers in aqueous systems. We measured the concentrations of (210)Pb and (210)Po in the dissolved (≤0.5 µm), bulk (unfiltered) and particulate phases (≥1 µm) collected in the Clinton River in the Lake St. Clair watershed in Southeast Michigan in order to investigate their partitioning between particulate and dissolved phases. Activity measurements of the dissolved and particulate phases revealed that an average of 38% (range: 12-59%) and 33% (range: 12-66%) of the total (210)Pb and (210)Po, respectively, in the water column was found in the particulate phase. The activity of dissolved and total (210)Pb was higher than that of (210)Po because of the higher atmospheric depositional fluxes of (210)Pb compared to (210)Po. Although the calculated Kd values of (210)Pb and (210)Po were similar, there was an inverse relationship between the Kd and suspended particulate matter concentration, indicating the presence of a particle concentration effect and we attribute this observation to the presence of significant amounts of colloidal (210)Po and (210)Pb in the dissolved phase. The fractionation factors for Po and Pb were found to be less than 1 in most cases. The first-order box model calculation-based residence times with respect to scavenging varied from 2 to 25 days for (210)Pb and 19-78 days for (210)Po, indicating higher particle-reactivity of (210)Pb compared to (210)Po.

Universal conductance and conductivity at critical points in integer quantum Hall systems.

The sample averaged longitudinal two-terminal conductance and the respective Kubo conductivity are calculated at quantum critical points in the integer quantum Hall regime. In the limit of large system size, both transport quantities are found to be the same within numerical uncertainty in the lowest Landau band, and , respectively. In the second-lowest Landau band, a critical conductance is obtained which indeed supports the notion of universality. However, these numbers are significantly at variance with the hitherto commonly believed value . We argue that this difference is due to the multifractal structure of critical wave functions, a property that should generically show up in the conductance at quantum critical points.

Utility quick test for analyzing materials for drinking water distribution systems for effect on taste-and-odor.

A workshop of international drinking water experts was convened in Sedona, Arizona, March 26-27, 2001 for the purpose of developing a method for testing drinking water system components for their potential to contribute to taste-and-odor problems in drinking water. The workshop participants derived a method using provisions from European Standards as well as newly developed approaches. It is intended that this method can serve as a temporary procedure for water utilities, as well as a recommended template to derive an official standard. Materials to be tested may include pipes, fittings, ancillaries, joints, lubricants, tanks, and reservoirs. The recommended method includes a migration (leaching) test with chlorinated water, followed by sensory analysis of the samples from the migration test after dechlorination. Sensory analyses use both statistical (e.g., triangle test) and descriptive (e.g. Flavor Profile Analysis) techniques. A decision tree for the results is provided.

Effects of chlorine and chloramines on earthy and musty odors in drinking water.

Water treatment plants in the US may operate under the assumption that chlorine masks earthy and musty odors from geosmin and 2-methylisoborneol (MIB) in drinking water. To test this hypothesis, we evaluated the effects of chlorine and chloramines on geosmin and MIB by two sensory analysis approaches--a statistical Pairwise Comparison Test, and Flavor Profile Analysis (FPA). All Pairwise Ranking test statistics were significant (p<0.05); we conclude that panelists can differentiate minor differences in geosmin and MIB concentrations in a Pairwise Comparison Test even in the presence of chlorine. FPA appeared to be more challenging in discerning subtle differences in concentrations of geosmin or MIB than did the Pairwise Comparison Test, and the presence of chlorine (0.5-20 mg/L) and chloramines (3-24 mg/L) confused the panelists (i.e showed a larger error in the intensity of response reported by the panel), but did not necessarily mask geosmin or MIB.

Materials used in drinking water distribution systems: contribution to taste-and-odor.

In order to assist drinking water utilities with identifying the possible sources and causes of taste-and-odor conditions associated with materials used in distribution systems, we evaluated information from case studies and a database from the National Sanitation Foundation (NSF), International. This database identified chemicals that had leached from drinking water system components during testing of materials under ANSI/NSF Standard 61, which provides information to water utilities on potential taste-and-odor and health concerns from the use of new materials. The data were arranged to provide a process for locating the potential source of a taste-and-odor event. After a sensory analysis is conducted on the drinking water samples, the descriptor can be matched with categories on the "Drinking Water Taste and Odor Wheel 2000" in order to suggest the candidate material.

Early GABA(A) receptor clustering during the development of the rostral nucleus of the solitary tract.

While there is an abundance of gamma-aminobutyric acid (GABA) in the gustatory zone of the nucleus of the solitary tract of the perinatal rat, we know that GABAergic synapse formation is not complete until well after birth. Our recent results have shown that GABA(B) receptors are present at birth in the cells of the nucleus; however, they do not redistribute and cluster at synaptic sites until after PND10. The present study examined the time course of appearance and redistribution of GABA(A) receptors in the nucleus. GABA(A) receptors were also present at birth. However, in comparison to GABA(B) receptors, GABA(A) receptors underwent an earlier translocation to synaptic sites. Extrasynaptic label, for example, of GABA(A) receptors was non-existent compared to GABA(B) receptors at PND10 and well-defined clusters of GABA(A) receptors could be seen as early as PND1. We propose that while GABA(A), receptors may play an early neurotransmitter role at the synapse, GABA(B) receptors may play a non-transmitter neurotrophic role.

Redistribution and increased specificity of GABA(B) receptors during development of the rostral nucleus of the solitary tract.

Recent results show that there is an abundance of gamma-aminobutyric acid (GABA) before GABAergic synapses have formed in the gustatory zone of the nucleus of the solitary tract. These results suggest that a non-synaptic, developmental function may exist for GABA prior to synaptogenesis. However, GABA exerts its physiological effect via its receptors, the development of which is a largely unknown process. The developmental expression of one of the GABA receptors in the young nucleus of the solitary tract is the focus of this study. The development of GABA(B) receptors was investigated by light and electron microscopy. The results suggest that before the development of GABAergic synapses, GABA(B) receptors are diffusely distributed. When GABAergic synapses form, the receptors become clustered. Quantitative postembedding immunohistochemical studies at the electron microscopic level show that extrasynaptic labeling for GABA(B) receptors decreases during development, but synaptic labeling increases. Increased specificity of neurotransmitter receptors at synapses has been shown in other systems during development, including other central nervous system structures, but this may be the first demonstration of the phenomenon using quantitative electron microscopy.

Levitation of current carrying states in the lattice model for the integer quantum Hall effect.

The disorder driven quantum Hall to insulator transition is investigated for a two-dimensional lattice model. The Hall conductivity and the localization length are calculated numerically near the transition. For uncorrelated and weakly correlated disorder potentials the current carrying states are annihilated by the negative Chern states originating from the band center. In the presence of correlated disorder potentials with correlation length larger than approximately half the lattice constant the floating up of the critical states in energy without merging is observed. This behavior is similar to the levitation scenario proposed for the continuum model.

Changes in GABA-immunoreactivity during development of the rostral subdivision of the nucleus of the solitary tract.

GABA plays an important role in the processing of gustatory information in the rostral nucleus of the solitary tract. The following study used post-embedment immunohistochemistry in the rat brainstem to localize GABA at both the light and electron microscopic levels to characterize the developmental distribution of GABA and synaptogenesis of GABA-immunoreactive terminals in the rostral nucleus of the solitary tract. During the first postnatal week, GABA is present in the rostral nucleus of the solitary tract, but less of it is synaptic than any time later in development. Of the few synaptic terminals present at postnatal day 1, less than 20% are GABA-immunoreactive. This proportion more than doubles to reach adult levels by postnatal day 10. By weaning (postnatal day 20), GABA-immunoreactive cells are found in nearly the same density as in the adult. Development continues after weaning and is characterized by a disproportionate loss of non-GABA-containing cells. Finally, one previously identified subtype of GABA-immunoreactive terminal matures very late during the postweaning phase of development. The study provides the first analysis of the development of GABA-related circuitry in the rostral nucleus of the solitary tract using anatomical methods. These data provide the background with which to view the emerging physiology of developing taste neurons.

Adoption and failure of the "Boyer model" at the University of Louisville.

In the 1990s two factors had a major impact on the promotion and tenure process at the University of Louisville (UL) School of Medicine. Clinical reimbursements declined, and as they did, faculty hired as income-generating clinicians continued to be evaluated as researchers. In addition, with legislation ending mandatory retirement, accountability and the requirement for demonstrations of continued competency increased. In part because of the need to recognize service and the need to evaluate post-tenure faculty, the Board of Trustees launched several ambitious initiatives that were collectively entitled "Redefinition of Faculty." The eventual acceptance of the policies under this umbrella included the adoption of the four kinds of scholarship defined by Ernest Boyer. However, because of faculty unrest regarding other facets of this initiative, compromises in the way that the Boyer model was adopted rendered the governance documents untenable. The difficulties with how the UL School of Medicine adopted the Boyer model are detailed, as are some of the lessons learned. Despite the difficulties, the concepts in Boyer's treatise have not been abandoned; the UL School of Medicine has embraced the need for a broadened view of scholarship in its newly emerging governance documents in which, for example, clinical service, formerly unrecognized as a promotable activity, is now recognized as such.

Development of salt-responsive neurons in the nucleus of the solitary tract.

The rodent gustatory system has become a popular and useful model for the study of brain development because of this system's protracted period of postnatal maturation and its sensitivity to subtle changes in the animal's sensory environment. The goal of this investigation was to improve our understanding of dendritic remodeling exhibited by second-order gustatory neurons by presenting a comprehensive and definitive description of the development of the dendritic architecture of taste-sensitive neurons in the rostral nucleus of the solitary tract. Extracellular and intracellular recording and intracellular labeling techniques were used to examine the structure and function of individual gustatory neurons in three groups of rats: (1) Postnatal day 13-21 (PND13-21), (2) Postnatal day 22-28 (PND22-28), and (3) Adult (postnatal day 60-90). We found that neurons that responded to all three of the salts in our taste array ("Salt Sensitive") exhibited a striking increase in the number of dendritic branch points, maximum branch order, swelling density, and spine density between the PND13-21 and PND22-28 periods. These increases were followed by a period of dendritic remodeling during which the values for all measures except spine density decreased significantly. The neurons that did not respond to all three salts exhibited no change in the number of dendritic branches, branch order, or spine density during development, but they did undergo a decrease in swelling density. We also found that there was a significant decrease in the total dendritic length and cell volume of Salt Sensitive neurons between the PND22-28 and Adult periods, whereas the cells that did not respond to all three salts exhibited an increase in dendritic length and cell volume between postnatal day 28 and adulthood. Finally, we found that the dendrites of the Adult Salt Sensitive neurons were more restricted in the rostrocaudal axis than either the PND13-21 or PND22-28 Salt Sensitive cells. In contrast, there were no significant changes in the rostrocaudal extent of the dendritic arbors of cells that did not respond to all three salts. When viewed in the context of the extant literature and our own preliminary studies that used modified salt diets, we propose that these results provide strong support for the hypothesis that there is a relationship between postnatal dendritic development (particularly remodeling) and the animal's sensitivity to salts.

Community characteristics associated with elder abuse.

OBJECTIVES: To help define the relationship between elder abuse rates and counties' demographics, healthcare resources, and social service characteristics. DESIGN: County-level data from Iowa were analyzed to test the association between county characteristics and rates of elder abuse between 1984 and 1993 using univariate correlation analysis and stagewise linear regression. SETTING: Ninety-nine counties in Iowa. PARTICIPANTS: Iowa residents aged 65 years and older. MEASUREMENTS: County-level population-adjusted numbers of abused elderly, abused children, children in poverty, high school dropouts, physicians and other healthcare providers, hospital beds, social workers and caseworkers in the Department of Human Services (DHS). RESULTS: Community characteristics that had a positive association with rates of reported or substantiated elder abuse at the P < .001 level were population density, children in poverty, and reported child abuse. Lower substantiated elder abuse rates were associated at P < .05 with higher community rates of high school dropouts, number of chiropractors, and number of nurse practitioners. After adjusting for number of DHS caseworkers and reported child abuse rates (a surrogate for workload) a district effect persists for substantiated elder abuse cases (P = .002). CONCLUSION: County demographics are risk factors for reported and substantiated elder abuse. The strongest risk factor for reported elder abuse was reported child abuse. The difference in districts may reflect differences in resources and/or differing characteristics of caseworkers who substantiate elder abuse. The risk factors may reflect conditions that influence the amount of elder abuse or the detection of existing elder abuse.

Structure and function of gustatory neurons in the nucleus of the solitary tract. IV. The morphology and synaptology of GABA-immunoreactive terminals.

In the visual, auditory and somatosensory systems, insight into the synaptic arrangements of specific types of neurons has proven useful in understanding how sensory processing within that system occurs. The neurotransmitter GABA is present in the nucleus of the solitary tract and based on the fact that the vast majority of cells respond to GABA, its agonists and antagonists, and that over 45% of synaptic terminals in the rostral subdivision of the nucleus of the solitary tract are GABA-immunoreactive, GABA is thought to play an important role in gustatory processing. The following study was carried out to establish the distribution of GABA-immunoreactive terminals within the nucleus of the solitary tract. Specifically, the distribution on to physiologically-identified gustatory neurons was determined using post-embedding electron immuno-histochemistry. GABA-immunoreactive terminals synapse with gustatory neuronal somata and all portions of their dendrites, but non-GABAergic terminals synapse only with distal dendrites of the gustatory cells and on to correspondingly small unidentified dendritic profiles in the neuropil. There is a differential distribution of two subtypes of GABA-immunoreactive terminals on to proximal and distal portions of the gustatory neurons as well. Finally, a model for the synaptic arrangements involving gustatory and GABAergic neurons is proposed.

Structure and function of gustatory neurons in the nucleus of the solitary tract. III. Classification of terminals using cluster analysis.

In sensory systems, insight into synaptic arrangements on cells of known physiological response properties has helped our understanding of the structural basis for these properties. To carry out these types of studies, however, synaptic types in the region of interest must be defined. Unfortunately, defining synaptic types in the brainstem has proved to be a challenging enterprise. Our study was done to classify synapses in the gustatory part of the nucleus solitarius using objective quantitative criteria and a cluster analysis procedure. Cluster analysis allows classification of a population of objects, such as synaptic terminals, into groups that exhibit similar characteristics. Six terminal types were identified using cluster analysis and subsequent analyses of variance and post hoc tests. Unlike classification schemes used for the cerebral cortex, where synaptic apposition density thickness and shape of vesicles is useful (Gray's Type I and II synapses), the concentration of vesicles in a terminal was a more useful measurement with which to classify terminals in the nucleus solitarius. To validate that vesicle density (vesicles/microm2) is a useful defining characteristic to classify terminals in the nucleus solitarius, terminals of a known type were used. GABAergic terminals were identified using postembedding immunohistochemical techniques, and their vesicle density was determined. GABAergic terminals fall into the range of two of the terminal types defined by the cluster analysis and, based on vesicle density, two types of GABAergic terminals were identified. We conclude that vesicle density is a helpful means to identify synapses in this brainstem nucleus.

Developmental changes in the dendritic architecture of salt-sensitive neurons in the nucleus of the solitary tract.

Recent studies have provided evidence that brainstem gustatory neurons undergo substantial dendritic growth during a period of postnatal development that coincides with the maturation of their response to salts, suggesting a relationship (perhaps causal) between the physiology and morphology of developing salt-sensitive neurons. In an initial effort to explore this issue, we used extracellular and intracellular recording and intracellular labeling techniques to examine the structure and function of individual gustatory neurons in the rostral nucleus of the solitary tract (rNST) of young (postnatal day [P] 22-28) and adult rats. We found that P22-28 cells that responded to all three of the salts in our taste array had a greater dendritic length, a greater cell volume, and more dendritic branches than the cells that responded to one salt. As a group, taste-sensitive neurons in P22-28 animals had a higher maximum dendritic branch order and a trend toward more dendritic branch points than gustatory neurons in adult animals. The dendritic arbors of P22-28 taste neurons that responded to all three salts were larger (greater surface area and volume), more extensive in the rostrocaudal axis and exhibited a higher maximum branch order, more branch points and higher swelling density than adult cells that responded to all three salts. These results demonstrate that the morphology of salt-sensitive gustatory neurons in developing animals is closely related to the number of salts that evoke a response. The data also support the postulate that gustatory neurons in the rat brainstem undergo substantial dendritic remodeling between the fourth week of life and adulthood. Dendritic remodeling may play an important role in the maturation of the rNST response to NaCl.

Localization of proteins associated with the outer hair cell plasma membrane in the gerbil cochlea.

There is substantial evidence that the motility of mammalian outer hair cells is generated close to or within the plasma membrane. Several analogies between the outer hair cell cortical lattice and the membrane-related cytoskeleton of erythrocytes have been noted. In erythrocytes a member of the anion exchanger protein family, AE1, also known as Band 3, is involved in membrane-cytoskeleton linkage via Protein 4.1. In the following paper, the presence of these two proteins in gerbilline outer hair cells is confirmed by western blot. Furthermore, co-localization of these two proteins was detected in the lateral wall of outer hair cells by immunofluorescence and postembedding electron immunohistochemistry. Band 3 is restricted to this region, whereas Protein 4.1 has a somewhat more dispersed distribution. Thus, the structure of these sensory receptor cells may result from an adaptation of a strategy used by other motile cells. The proteins investigated likely have a support function and may comprise "pillars" seen between the lateral plasma membrane and the cytoskeleton in micrographs of outer hair cells. The possibility that Band 3 comprises "protein particles" seen in the lateral plasma membrane, or maybe directly involved in the voltage-dependent force generation in outer hair cells, is also discussed.

Expression of chemokine receptors by subsets of neurons in the central nervous system.

IL-8 is expressed by activated and neoplastic astrocytes and enhances the survival of hippocampal neurons in vitro. Since mRNA encoding chemokine receptors have been demonstrated in brain, the expression of chemokine receptors by specific cell types in anatomic regions of the central nervous system (CNS) was investigated. Archival tissues from various regions of the CNS were stained with specific mAbs to the Duffy Ag/receptor for chemokines, a promiscuous receptor that binds selected chemokines; the specific receptor for IL-8 (CXCR1); and the receptor (CXCR2) shared by IL-8 and melanoma growth stimulatory activity. The Duffy Ag/receptor for chemokines was expressed exclusively by Purkinje cells in the cerebellum. Chemokine binding and radioligand cross-linking confirmed the presence of a high affinity, promiscuous chemokine receptor in the cerebellum. Although CXCR1 was not expressed in the CNS, CXCR2 was expressed at high levels by subsets of projection neurons in diverse regions of the brain and spinal cord, including the hippocampus, dentate nucleus, pontine nuclei, locus coeruleus, and paraventricular nucleus, and in the anterior horn, interomediolateral cell column, and Clarke's column of the spinal cord. Fibers that express CXCR2 included those in the superior cerebellar peduncle and the substantia gelatinosa. Immunohistochemical analysis of the involved brain tissues from patients with Alzheimer's disease revealed expression of CXCR2 in the neuritic portion of plaques surrounding deposits of amyloid. These data suggest that chemokines may play a role in reactive processes in normal neuronal function and neurodegenerative disorders.

The use of cluster analysis for cell typing.

In invertebrates, large neurons, identifiable in each animal, have proven to be useful models for investigating basic neurobiological phenomena. In vertebrates, the number of neurons and the complexity of nervous systems increase and 'identifiability' is lost. To compensate for this, other approaches must be adopted to study the vertebrate brain. One successful approach has been to identify cell types, recognizable in each individual. The identification of cell types in central nuclei has helped us understand the organization of these nuclei and has provided an important foundation for examining possible relationships between the structure and function of neurons. Unfortunately, not all nuclei are composed of neurons of readily identifiable types. Nuclei lacking distinct cell types are, in general, less well understood than nuclei with morphologically distinct cell types. This article describes a statistical approach known as cluster analysis that we used to define cell types in the nucleus of the solitary tract-a nucleus that had been suggested to contain identifiable cell types but within which cell typing had proven difficult. Similar techniques have been used to classify Golgi-impregnated cells in the ventrobasal complex of the dog, the subthalamic nucleus of the bushbaby and the human retina. Cluster analysis has also been used in the gustatory system, in general, and nucleus of the solitary tract, in specific, to classify electrophysiologically characterized cells. The method also includes a technique for verifying the utility of the resulting classification.

Anatomical correlates of the passive properties underlying the developmental shift in the frequency map of the mammalian cochlea.

As the cochlea develops, the cells in the basal cochlea become sensitive to progressively higher frequencies. To identify features of cochlear morphology that may underlie the place code shift, measurements of infant and adult gerbil cochleas were made at both the light and electron microscopic levels. The measurements included areas of the cochlear duct, basilar membrane, and organ of Corti, height and width of the basilar membrane, thickness of the tympanic cover layer, thickness of the upper and lower basilar membrane fiber bands, and optical density of the basilar membrane. The results indicated that basilar membrane dimensions do not change as the place code shifts and that regions that code for the roughly the same frequency (e.g., approximately 11.2 kHz) at different ages can have basilar membranes of very different dimensions. In contrast, the size of the organ of Corti and the thickness of fiber bands inside the basilar membrane do change in ways consistent with the shift in the frequency map.