Bioelectrical impedance analysis is more accurate than clinical examination in determining the volaemic status of elderly patients with fragility fracture and hyponatraemia.

OBJECTIVES: Management of hyponatraemia depends crucially on accurate determination of volaemic (hydration) status but this is notoriously challenging to measure in older people. Bioelectrical impedance analysis (BIA) provides a validated means of determining total body water (TBW), but its clinical utility in determining volaemic status in hyponatraemia has never been tested. This study assessed the utility of BIA in the clinical management of hyponatraemia in elderly patients with fragility fractures (EPFF), a group at high risk of hyponatraemia. DESIGN: Prospective observational study of consenting patients ≥65 years with fragility fractures (N=127). SETTING: University teaching hospital in Scotland. PARTICIPANTS: Patients ≥665 years with fragility fractures with capacity to consent to participation. MEASUREMENTS: BIA and standard clinical examination procedures (jugular venous distension, skin turgor, mouth and axillary moistness, peripheral oedema, capillary refill time, overall impression) were performed daily throughout each participant's hospital stay. Volaemic status of hyponatraemia was determined by an expert panel using clinical data (history, examination, nursing observations and laboratory tests) blinded to TBW readings. Cohen's kappa was calculated to assess the level of agreement between the expert panel and both BIA and standard clinical examination measures in determining the volaemic state of hyponatraemia. RESULTS: 26/33 (79%) cases of hyponatraemia had sufficient clinical information to allow determination of volaemic status by BIA. There was moderate level of agreement between BIA and the expert panel, kappa 0.52 (p<.001). All kappa values for standard clinical assessments of volaemic status neared zero, indicating nil to slight agreement. CONCLUSION: BIA outperformed all aspects of the standard clinical examination in determining the volaemic status of hyponatraemic EPFF, suggesting it may be useful in clinical practice.

Effects of reduced winter duration on seed dormancy and germination in six populations of the alpine herb Aciphyllya glacialis (Apiaceae).

The life stages of seed germination and seedling establishment play a vital role in maintaining plant populations and determining range dynamics of species. Thus, it is not surprising that specific germination requirements and dormancy mechanisms have evolved in all major angiosperm clades. In a rapidly changing climate, we face growing pressure to manage, conserve and restore native plant species and communities. To achieve these aims, we require solid knowledge of whether and how seed germination requirements and dormancy status vary between different populations of a given species and how germination strategies may be affected by warming climatic conditions. We assessed the effect of decreasing durations of cold stratification (i.e. conditions representing a shortened winter as predicted under climate change) on germination and dormancy of the alpine herb Aciphylla glacialis. Our results confirmed previous research showing that A. glacialis seeds possess physiological dormancy that can be alleviated by cold stratification. In addition, the results demonstrated that A. glacialis seeds have underdeveloped embryos at dispersal; these grow to germinable size following 4-9 weeks at both constant 5°C and 10-5°C (day-night) temperatures. We conclude that A. glacialis exhibits morphophysiological dormancy. Furthermore, we found that the final percentage germination and dormancy status varied significantly among natural populations and that this variation did not correlate with elevation at the site of seed origin. Seeds germinated following 6-8 weeks of cold stratification, and seedlings showed no detrimental effects as a result of shorter stratification periods. Together, these results suggest that reduced duration of winter is unlikely to have direct negative impacts on germination or early seedling growth in A. glacialis. The causes and implications of the population variation in germination traits are discussed.

Volaemic assessment of the elderly hyponatraemic patient: reliability of clinical assessment and validation of bioelectrical impedance analysis.

BACKGROUND: Hyponatraemia is the commonest electrolyte disturbance of hospital inpatients. Assessment of volaemic status is an important part of diagnosis and management. AIM: To determine reliability of clinical assessment of volaemic state by assessing inter-observer variability of clinical measures of volaemic state. To assess validity of bioelectrical impedance analysis as a tool to measure total body water in elderly hyponatraemic patients. DESIGN: Observational study conducted in a Department of Medicine for the Elderly. METHODS: Hospital inpatients >65 years old (n=22) with serum sodium concentration <130 mmol/l were included. Two assessors determined volaemic state on two occasions 72 h apart. Level of agreement between observers was determined on each occasion. Total body water estimation was undertaken with bioelectrical impedance analysis and measurement of dilution of deuterium oxide. Correlation between these two measures was then analysed. RESULTS: Cohen's κ for agreement between two observers for overall assessment of volaemic state was 0.59 (P<0.01). Values for agreement between individual clinical markers of volaemic state ranged between 0.16 and 0.45. Pearson correlation coefficient (r) for correlation between estimation of total body water undertaken by bioelectrical impedance analysis and by measurement of dilution of deuterium oxide was 0.69 (P<0.001). CONCLUSION: There was moderate inter-observer agreement of overall clinical volaemic assessment of elderly hyponatraemic patients. Total body water estimation by bioelectrical impedance analysis correlates well with estimation by measurement of dilution of deuterium oxide, providing a potentially useful tool to improve the management of the elderly hyponatraemic patient.

Mimicking a semi-arid tropical environment achieves dormancy alleviation for seeds of Australian native Goodeniaceae and Asteraceae.

BACKGROUND AND AIMS: Seed physiological dormancy (PD) limits the use and conservation of some of Queensland's (Qld) native forb species. It was hypothesised that optimum dormancy-alleviating treatments would reflect environmental conditions that seeds experience in situ, and this premise was tested for PD seeds of four species native to south-west Qld. METHODS: High temperatures and increased rainfall during summer are characteristic of this semi-arid tropical environment. Ex situ treatments were designed to mimic conditions that seeds dispersed in spring experience during the summer months before germinating in cooler autumn temperatures. Seeds received between 4 and 20 weeks of a dry after-ripening (DAR), warm stratification or dry/wet cycling treatment (DAR interspersed with short periods of warm stratification), in darkness, before being transferred to germination test conditions. In addition, natural dormancy alleviation of one of the Goodeniaceae species was investigated in situ. KEY RESULTS: Dry/wet cycling resulted in higher levels of germination of Actinobole uliginosum (Asteraceae), Goodenia cycloptera and Velleia glabrata (Goodeniaceae) when compared with constant DAR or stratification, while Goodenia fascicularis (Goodeniaceae) responded better to short durations of warm stratification. Long durations of DAR partially alleviated PD of A. uliginosum; however, stratification induced and maintained dormancy of this species. Modifications to the dry/wet cycling treatment and germination test conditions based on data collected in situ enabled germination of G. cycloptera and V. glabrata to be further improved. CONCLUSIONS: Treatments designed using temperature, relative humidity and rainfall data for the period between natural seed dispersal and germination can successfully alleviate PD. Differences between the four species in conditions that resulted in maximum germination indicate that, in addition to responding to broad-scale climate patterns, species may be adapted to particular microsites and/or seasonal conditions.

Distributed situation awareness in dynamic systems: theoretical development and application of an ergonomics methodology.

The purpose of this paper is to propose foundations for a theory of situation awareness based on the analysis of interactions between agents (i.e. both human and non-human) in subsystems. This approach may help to promote a better understanding of technology-mediated interaction in systems, as well as helping in the formulation of hypotheses and predictions concerning distributed situation awareness. It is proposed that agents within a system each hold their own situation awareness, which may be very different from (although compatible with) that of other agents. It is argued that we should not always hope for, or indeed want, sharing of this awareness, as different system agents have different purposes. This view marks situation awareness as a dynamic and collaborative process binding agents together on tasks on a moment-by-moment basis. Implications of this viewpoint for the development of a new theory of, and accompanying methodology for, distributed situation awareness are offered.

Nerve growth factor induces increased airway inflammation via a neuropeptide-dependent mechanism in a transgenic animal model of allergic airway inflammation.

BACKGROUND: Nerve growth factor (NGF) exerts an important functional impact on the pathogenesis of allergic diseases. Data obtained in animal models of allergic bronchial asthma indicate that NGF alters sensory nerve function and promotes allergic inflammation, bronchial hyper-reactivity, and airway obstruction. OBJECTIVE: To further delineate the effects of NGF on airway inflammation, we employed a transgenic (tg) animal model of allergic inflammation and asthma. METHODS: NGF-tg mice, which overexpress NGF in Clara cells of the airways, were compared with wild-type (wt) littermates regarding their ability to mount IgE-related airway inflammatory responses. Mice were sensitized intraperitoneally to ovalbumin (OVA) and locally challenged via the airways according to established protocols. RESULTS: NGF-tg mice displayed enhanced levels of OVA-specific IgE antibody titres after repeated OVA aerosol exposure. In the airways, increased numbers of eosinophils were detected. These results were confirmed to be NGF specific, because similar results were obtained following local application of NGF into the airways of wt mice. The effect of NGF was partly mediated via neuropeptides, as treatment of OVA-sensitized NGF-tg mice with the dual neurokinin (NK) receptor NK-1/NK-2 antagonist partly prevented enhanced airway inflammation. CONCLUSION: The present data indicate an important functional role of NGF in allergic airway inflammation and point to an involvement of tachykinins as mediators of NGF effects.

Leptin receptor expression in fetal lung increases in late gestation in the baboon: a model for human pregnancy.

Leptin produced by both adipose tissue and the placental trophoblast, has been proposed to regulate numerous aspects of human conceptus development. Although recent animal studies have suggested an additional role for the polypeptide in fetal lung maturation, no evidence has been reported in primates. Therefore, we employed the baboon (Papio sp.), a well-characterized primate model for human pregnancy, to determine the presence and ontogeny of leptin receptor in fetal lung with advancing gestation. Lungs were collected from fetal baboons, early in gestation (days 58-62, n = 4), at mid gestation (days 98-102, n = 4), and late in gestation (days 158-165, n = 4) (term 184 days). mRNA transcripts for leptin (LEP) and both long and short intracellular domain isoforms of the leptin receptor (LEP-R(L) and LEP-R(S)) were assessed by RT-PCR. leptin receptor protein was evaluated by immunoblotting and cell types expressing leptin receptor were identified in late pregnancy by immunohistochemistry. Fetal serum leptin concentrations, determined by RIA, remained relatively unchanged at 5.7 +/- 1.1 ng/ml (mean +/- s.e.m.) in mid pregnancy and 8.4 +/- 3.0 ng/ml in late pregnancy (P > 0.05). Although leptin were detectable in fetal lung, no changes in transcript abundance were apparent with advancing gestation. However, transcripts for both LEP-R(L) and LEP-R(S) receptor isoforms increased several-fold (P < 0.05) in fetal lung between mid and late gestation, while leptin receptor protein was detectable only in late pregnancy. leptin receptor was localized in distal pulmonary epithelial cells, including type II pneumocytes. In conclusion, leptin is present in the fetal baboon and its receptor is enhanced during late gestation in cells responsible for the synthesis of pulmonary surfactant. Collectively, these and past findings may suggest a modulatory role for the polypeptide in pulmonary development and/or may identify leptin receptor as a physiological marker of primate fetal lung maturity.

Sensory nerves promote ozone-induced lung inflammation in mice.

Genetically manipulated mice exhibiting altered innervation of the airways were used to examine the role of sensory nerves in ozone-induced lung inflammation. Transgenic mice expressing nerve growth factor (NGF) from the lung-specific Clara cell secretory protein (CCSP) promoter exhibit hyperinnervation of the airways by sympathetic and tachykinin-containing sensory nerve fibers. Mice carrying a mutation in the low-affinity NGF receptor (NGFR) gene possess deficits in sensory innervation. CCSP-NGF transgenic mice exhibited a twofold increase in the number of lung lavage neutrophil level whereas NGFR knockout mice exhibited a nearly 50% decrease in neutrophilic inflammation compared with wild-type mice 18 h after ozone inhalation. Treatment with neurokinin receptor antagonists reduced the level of neutrophilic inflammation in both wild-type and CCSP-NGF mice. Examination of lavage fluid cytokine concentrations revealed that 4 h after ozone exposure CCSP-NGF mice produced significantly higher amounts of the chemokine KC than wild-type mice exposed to ozone. The results of this study indicate that sensory nerves are important mediators of ozone-induced inflammation in mice.

Nerve growth factor induces airway hyperresponsiveness in mice.

BACKGROUND: Previous studies indicated an upregulation of nerve growth factor (NGF) production during allergic inflammation. However, the function of NGF in the lungs is currently poorly understood. It was suggested that NGF could play an important role in the pathophysiology of airway hyperresponsiveness. The regulatory network between immunological events and altered neuronal control of airway smooth muscle contractility remains to be defined. METHODS: NGF was delivered into the airways of mice either by nasal instillation or by genetic engineering. Airway reactivity was then measured by electrical field stimulation. RESULTS: Treatment of mice with NGF induced airway hyperresponsiveness to a similar extent as demonstrated in allergen-sensitized mice. NGF-transgenic mice, overexpressing NGF in Clara cells, were hyperreactive in comparison to wild-type mice. CONCLUSION: These data suggest that NGF by itself determines the induction of airway hyperresponsiveness in the absence of airway inflammation in mice.

Overexpression of PDGF-A in the lung epithelium of transgenic mice produces a lethal phenotype associated with hyperplasia of mesenchymal cells.

Transgenic mice expressing platelet-derived growth factor A chain (PDGF-A) in the distal lung epithelium from the surfactant protein C (SPC) promoter were generated to investigate the role of this growth factor in lung development. Expression of the SPC-PDGFA transgene resulted in an enlarged, nonfunctional lung and perinatal lethality caused by failure to initiate ventilation. Histologic analysis of embryonic day (E) 16.5 lungs revealed increased mesenchymal cells and acinar buds and decreased bronchioles and dilated airspaces in SPC-PDGFA transgenic mice. At E18.5, nontransgenic lungs exhibited lung morphology typical of the saccular stage of lung development, including dilated airspaces, thin respiratory epithelium and mesenchyme, and elastin fiber deposition in primary septa. In contrast, E18.5 transgenic lungs retained many features of the canalicular stage of lung development, including undilated airspaces, cuboidal respiratory epithelium, thickened mesenchyme, and lack of parenchymal elastin deposition. These results indicate that PDGF-A is a potent growth factor for mesenchymal cells in the developing lung and that the downregulation of PDGF-A expression that normally occurs in the lung during late gestation is required for transition from the canalicular to the saccular stage of lung development.

Emphysematous lesions, inflammation, and fibrosis in the lungs of transgenic mice overexpressing platelet-derived growth factor.

Because of its expression pattern and its potent effects on mesenchymal cells, platelet-derived growth factor (PDGF) has been implicated as an important factor in epithelial-mesenchymal cell interactions during normal lung development and in the pathogenesis of fibrotic lung disease. To further explore the role of PDGF in these processes, we have developed transgenic mice that express the PDGF-B gene from the lung-specific surfactant protein C (SPC) promoter. Adult SPC-PDGFB transgenic mice exhibited lung pathology characterized by enlarged airspaces, inflammation, and fibrosis. Emphysematous changes frequently occurred throughout the lung, but inflammation and fibrotic lesions were usually confined to focal areas. The severity of this phenotype varied significantly among individual mice within the same SPC-PDGFB transgenic lineage. A pathology similar to that observed in adult mice was noted in lungs from transgenic mice as young as 1 week of age. Neonatal transgenic mice exhibited enlarged saccules and thickened primary septa. Results of these studies indicated that overexpression of PDGF-B induced distinct abnormalities in the developing and adult lung and led to a complex phenotype that encompassed aspects of both emphysema and fibrotic lung disease.

Reduced tumor necrosis factor-alpha and transforming growth factor-beta1 expression in the lungs of inbred mice that fail to develop fibroproliferative lesions consequent to asbestos exposure.

Tumor necrosis factor (TNF)-alpha and transforming growth factor (TGF)-beta mRNA and protein expression and the degree of fibroproliferative response to inhaled asbestos fibers are clearly reduced in the 129 inbred mouse strain as compared with typical fibrogenesis observed in the C57BL/6 inbred strain. The C57BL/6 mice showed prominent lesions at bronchiolar-alveolar duct (BAD) junctions where asbestos fibers deposit and responding macrophages accumulate. The 129 mice, however, were generally indistinguishable from controls even though the numbers of asbestos fibers deposited in the lungs of all exposed animals were the same. Quantitative morphometry of H&E-stained lung sections comparing the C57BL/6 and 129 mice showed significantly less mean cross-sectional area of the BAD junctions in the 129 animals, apparent at both 48 hours and 4 weeks after exposure. In addition, fewer macrophages had accumulated at these sites in the 129 mice. Nuclear bromodeoxyuridine immunostaining demonstrated that the number of proliferating cells at first alveolar duct bifurcations and in adjacent terminal bronchioles was significantly reduced in the 129 strain compared with C57BL/6 mice at 48 hours after exposure (P < 0.01). TNF-alpha and TGF-beta1 gene expression, as measured by in situ hybridization, was reduced in the 129 mice at 48 hours after exposure, and expression of TNF-alpha and TGF-beta1 protein, as measured by immunohistochemistry, was similarly reduced or absent in the 129 animals. We postulate that the protection afforded the 129 mice is related to reduction of growth factor expression by the bronchiolar-alveolar epithelium and lung macrophages.

Alveolar macrophage apoptosis and TNF-alpha, but not p53, expression correlate with murine response to bleomycin.

Apoptosis is considered to be a protective mechanism that limits lung injury. However, apoptosis might contribute to the inflammatory burden present in the injured lung. The exposure of mice to bleomycin (BLM) is a well-established model for the study of lung injury. BLM exposure induces DNA damage and enhances tumor necrosis factor (TNF)-alpha expression in the lung. To evaluate the importance of alveolar macrophage (AM) apoptosis in the pathogenesis of lung injury, we exposed BLM-sensitive (C57BL/6) and BLM-resistant (BALB/c) mice to BLM (120 mg/kg) and studied the induction of apoptosis [by light-microscopy changes (2, 8, 12, 24, 48, and 72 h) and annexin V uptake by flow cytometry (24 h)], the secretion of TNF-alpha (measured by ELISA), and the expression of p53 (by immunoblotting) in AM retrieved from these mice. BLM, but not vehicle, induced apoptosis in AM from both murine strains. The numbers of apoptotic AM were significantly greater (P < 0.001) in C57BL/6 mice (52.9%) compared with BALB/c mice (40.8%) as demonstrated by annexin V uptake. BLM induction of apoptosis in AM was preceded by an increased secretion of TNF-alpha in C57BL/6 but not in BALB/c mice. Furthermore, double TNF-alpha receptor-deficient mice, developed on a C57BL/6 background, demonstrated significantly (P < 0.001) lower numbers of apoptotic AM compared with C57BL/6 and BALB/c mice. BLM also enhanced p53 expression in AM from both murine strains. However, p53-deficient mice developed BLM-induced lung injury, exhibited similar lung cell proliferation (measured as proliferating cell nuclear antigen immunostaining), and accumulated similar amounts of lung hydroxyproline (65 +/- 6.9 microgram/lung) as did C57BL/6 (62 +/- 6.5 microgram/lung) mice. Therefore, AM apoptosis is occurring during BLM-induced lung injury in a manner that correlates with murine strain sensitivity to BLM. Furthermore, TNF-alpha secretion rather than p53 expression contributes to the difference in murine strain response to BLM.tumor necrosis factor; strain susceptibility

TNF-alpha receptor knockout mice are protected from the fibroproliferative effects of inhaled asbestos fibers.

We have demonstrated that C57BL/6-129 hybrid mice with genes for both the 55kd and 75kd receptors for TNF-alpha knocked out (TNF-alphaRKO) fail to develop fibroproliferative lesions after asbestos exposure. There is good evidence that TNF-alpha plays a major role in mediating interstitial pulmonary fibrosis. Our findings support this view and we present here new data obtained by in situ hybridization showing that expression of the genes coding for transforming growth factor alpha (TGF-alpha) and platelet-derived growth factor A-chain (PDGF-A) is reduced in the TNF-alphaRKO mice compared with control animals. In accordance with this observation, data on bromodeoxyuridine (BrdU) incorporation in the lungs of the TNF-alphaRKO mice show no increases over unexposed control animals. In contrast, wild-type control mice exposed to asbestos exhibit 15- to 20-fold increases in BrdU uptake and consequently develop fibrogenic lesions. Even though the levels of TNF-alpha gene expression and protein production were increased in the asbestos-exposed TNF-alphaRKO mice, the lack of receptor signaling protected the mice from developing fibroproliferative lesions. We agree with the view that TNF-alpha is essential for the development of interstitial pulmonary fibrosis and postulate that TNF-alpha mediates its effects through activation of other growth factors such as PDGF and TGF-alpha that control cell growth and matrix production.

Expression of TNF and the necessity of TNF receptors in bleomycin-induced lung injury in mice.

Bleomycin (BLM) induction of lung fibrosis in mice is an established model to study the mechanism of pulmonary fibrosis. Cytokine secretion has been implicated as a fundamental component of the lung fibrotic process observed in response to BLM. Among the cytokines implicated in lung fibrosis, Tumor necrosis factor (TNF) alpha has been considered to play a fundamental role. In the present study, we characterized the cellular sources of TNF during BLM-induced lung injury and examined the importance of TNF receptors in this process. To characterize the expression of TNF, we utilized two strains of mice, one sensitive (C57BL/6) and one resistant (BALB/c) to BLM-induced lung injury. Mice received BLM (120 mg/kg total) or saline, as control, by multiple subcutaneous injections. BLM induced the development of inflammation in subpleural areas only in the lungs of BLM-sensitive mice. These subpleural areas were characterized by infiltration of CD68-positive macrophages and increased collagen deposition. BLM enhanced the expression of TNF mRNA in BLM-sensitive, but not in BLM-resistant, mice. In situ hybridization studies localized the expression of TNF in the areas of BLM-induced inflammation in 6% and 27% of macrophages at 14 and 21 days post BLM treatment. In addition to TNF, BLM exposure resulted in the upregulated expression of transforming growth factor (TGF)-beta 1, but not interleukin (IL)-1, mRNA in the lungs of both murine strains at 14 and 21 days. This upregulated expression of TGF-beta 1 mRNA was greater in the lungs of BLM-sensitive mice. In separate experiments, double TNF receptor knockout mice were exposed to BLM. These animals demonstrated an increased expression of TNF, but not TGF-beta 1, mRNA in response to BLM and did not exhibit histologic evidence of lung injury following BLM exposure. In summary, the upregulation of TNF mRNA in macrophages correlated with the appearance of inflammation following BLM exposure and was limited to the BLM-sensitive strain. Furthermore, in addition to the release of the TNF ligand, it appears that the presence of TNF receptors is necessary for the development of BLM-induced lung injury, and signaling through these receptors may contribute to the regulation of the TGF-beta 1 mRNA expression observed in response to bleomycin. These results provide further support for a role of macrophages and TNF in the induction of lung inflammation.