Characterising group-level brain connectivity: A framework using Bayesian exponential random graph models.

The brain can be modelled as a network with nodes and edges derived from a range of imaging modalities: the nodes correspond to spatially distinct regions and the edges to the interactions between them. Whole-brain connectivity studies typically seek to determine how network properties change with a given categorical phenotype such as age-group, disease condition or mental state. To do so reliably, it is necessary to determine the features of the connectivity structure that are common across a group of brain scans. Given the complex interdependencies inherent in network data, this is not a straightforward task. Some studies construct a group-representative network (GRN), ignoring individual differences, while other studies analyse networks for each individual independently, ignoring information that is shared across individuals. We propose a Bayesian framework based on exponential random graph models (ERGM) extended to multiple networks to characterise the distribution of an entire population of networks. Using resting-state fMRI data from the Cam-CAN project, a study on healthy ageing, we demonstrate how our method can be used to characterise and compare the brain's functional connectivity structure across a group of young individuals and a group of old individuals.

Assessing dynamic functional connectivity in heterogeneous samples.

Several methods have been developed to measure dynamic functional connectivity (dFC) in fMRI data. These methods are often based on a sliding-window analysis, which aims to capture how the brain's functional organization varies over the course of a scan. The aim of many studies is to compare dFC across groups, such as younger versus older people. However, spurious group differences in measured dFC may be caused by other sources of heterogeneity between people. For example, the shape of the haemodynamic response function (HRF) and levels of measurement noise have been found to vary with age. We use a generic simulation framework for fMRI data to investigate the effect of such heterogeneity on estimates of dFC. Our findings show that, despite no differences in true dFC, individual differences in measured dFC can result from other (non-dynamic) features of the data, such as differences in neural autocorrelation, HRF shape, connectivity strength and measurement noise. We also find that common dFC methods such as k-means and multilayer modularity approaches can detect spurious group differences in dynamic connectivity due to inappropriate setting of their hyperparameters. fMRI studies therefore need to consider alternative sources of heterogeneity across individuals before concluding differences in dFC.

[GP medication prioritisation in older patients with multiple comorbidities recently discharged from hospital: a case-based bottom-up approach]. / Hausärztliche Arzneimittelpriorisierung bei stationär entlassenen, multimorbiden, älteren Patienten--Ein Vignetten-Ansatz aus der Hausarzt-Perspektive.

INTRODUCTION: After the hospital discharge of older patients with multiple morbidities, GPs are often faced with the task of prioritising the patients' drug regimens so as to reduce the risk of overmedication. AIM: How do GPs prioritise such medications in multimorbid elderly patients at the transition between inpatient and home care? The experience by the GPs is documented in typical case vignettes. METHOD: 44 GPs in Sachsen-Anhalt were recruited--they were engaged in focus group discussions and interviewed using semi-standardised questionnaires. Typical case vignettes were developed, relevant to the everyday care that elderly patients would typically receive from their GPs with respect to their drug optimisation. RESULTS: According to the results of the focus groups, the following issues affect GPs' decisions: drug and patient safety, their own competence in the health system, patient health literacy, evidence base, communication between secondary and primary care (and their respective influences on each other). When considering individual cases, patient safety, patient wishes, and quality of life were central. This is demonstrated by the drug dispositions of one exemplary case vignette. CONCLUSIONS: GPs do prioritise drug regimens with rational criteria. Initial problem delineation, process documentation and the design of a transferable product are interlinking steps in the development of case vignettes. Care issues of drug therapy in elderly patients with multiple morbidities should be investigated further with larger representative samples in order to clarify whether the criteria used here are applied contextually or consistently. Embedding case vignettes into further education concepts is also likely to be useful.

Ageing with an intellectual disability: the impact of personal resources on well-being.

BACKGROUND: The population of ageing people with mild and moderate intellectual disabilities (ID) is growing rapidly. This study examines how personal resources (physical health, mental health and social networks) impact the well-being of ageing people with ID. METHODS: Longitudinal survey data on 667 people with a mild or moderate ID were acquired via interviews in 2006 and 2010. Indicators of personal resources (physical health, mental health and social networks) were assessed, as were indicators of well-being (satisfaction with life, happiness and loneliness). Additionally, data on background characteristics and autonomy were gathered. RESULTS: The results show that age is positively related to decreased mobility and auditory disabilities and negatively related to independent living, autonomy in how one spends one's leisure time and autonomy in decision-making. Longitudinal analyses demonstrated that, with the exception of health that deteriorated, and social satisfaction that improved, almost all variables remained stable over the 4-year period. Further, good physical health in 2006 predicted happiness in 2010. CONCLUSION: Despite the fact that age is associated with poorer physical and mental health and a smaller social network, this study showed that older people with ID have relatively high levels of well-being. Findings are discussed in the light of coping with ageing and impact of life events.

[Mild bleeding diathesis in a 62-year-old woman with hereditary thrombocytopenia]. / Milde Blutungsneigung bei einer 62-Jährigen mit hereditärer Thrombozytopenie.

A 62-year-old woman presented with severe, isolated thrombocytopenia. Due to the positive family history and normal thrombocyte morphology ANKRD26-associated thrombocytopenia 2 (THC2) was suspected. The diagnosis was confirmed by DNA sequencing. Although this is the first case report on THC2 in Germany, we anticipate that THC2 might be a frequent cause of hereditary thrombocytopenia. A specific therapy was not necessary, but would consist of platelet supplementation.

[Clinical trials in children--between the expectations of scientific requirements, the assurance of proven treatment and ethical demands]. / Klinische Prüfung an Kindern im Spannungsfeld zwischen wissenschaftlichen Anforderungen, der Sicherstellung der korrekten Behandlung und ethischen Aspekten.

Regulation (EC) No. 1901/2006 of the European Parliament and the Council dated 12 December 2008 on medicinal products for paediatric use is the result of a survey by the European Commission, concluding that children in the European Union are inadequately treated with medicinal products. The Regulation is addressed to the pharmaceutical industry with the intention to place medicinal products on the market and to the Member States to register all information on medicinal products for the treatment of children. The pharmaceutical industry will be obliged to conduct clinical trials in children for new medicinal products and medicinal products still under patent. This will be supported by incentives and rewards. As a consequence of the requirement to conduct clinical trials in children the framework and conditions have to be defined and ethical considerations have to be respected.

Aetiology of adult burns treated from 2000 to 2012 in a Swiss University Hospital.

BACKGROUND: Burns in Switzerland are frequent and lead to high economic and social costs. However, little is known about the aetiology of burns suffered by patients seeking treatment in hospital emergency departments. This knowledge could be used to develop preventive measures. METHODS: This retrospective analysis included all patients (≥16 years old) with acute thermal injuries of known cause admitted to the adult emergency department in Bern University Hospital (Switzerland, not a specialised burns unit) between 2000 and 2012. Clinical and sociodemographic data were extracted from medical records, i.e. the environment in which the burn occurred, as well as details of burn severity and aetiology. RESULTS: Seven hundred and one (701) patients with a mean age of 35.0±14.5 years (56% men) were included in the analysis. The winter season and the days around Christmas, turn of the year and Swiss National Day were identified as times with high risk of burns. Household (45%) and workplace (31%) were the most common locations/settings in which the burns occurred. Approximately every second burn was caused by scald, every fourth by flame and every seventh by hot objects. The analysis identified cooking, tar and electricity in workplace accidents, barbecues and the use of gasoline as aetiological factors in burns in leisure time, together with water in domestic thermal injuries. Burns occurred predominantly on non-protected skin on the hand and arms. The most severe burns were seen in electrical and flame burns. Men suffered more severe burns than women in all settings except psychopathology. CONCLUSIONS: The data suggest that the incidence and severity of burns in Switzerland could be reduced by preventive strategies and public campaigns, including education on fire protection systems, raising awareness about the times and locations where the risks of burns are greater, further improvement in workplace safety, particularly with cooking facilities and electrical equipment, and the development of innovative safety devices (i.e. machines, protective gloves). These findings have to be interpreted carefully, as this study includes only adult patients who presented in our ED and, in most cases, the burns covered less than 20% of the body surface.

[Serous vascularized pigment epithelial detachment in exudative AMD. Morphological typing and risk of tears in the RPE]. / Seröse vaskularisierte Pigmentepithelabhebungen bei exsudativer altersbedingter Makuladegeneration : Morphologische Typisierung und Risiko eines Einrisses im retinalen Pigmentepithel.

PURPOSE: Are there any morphological parameters in pigment epithelial detachment (PED) in eyes with age-related macular degeneration (AMD), which could identify the development of tears (RIP) in the retinal pigment epithelium (RPE) before initiation of anti-vascular endothelial growth factor (VEGF) therapy? METHODS: Retrospectively, the spectral domain optical coherence tomography (SD-OCT), FLA and near infrared (NIR) images of 98 eyes with PED in exudative AMD before treatment (ranibizumab or bevacizumab) were analyzed. Eyes in which a tear in the RPE (RIP group) could be observed during treatment were compared to eyes without the development of RIP (PED group) in the following morphological parameters of PED: height, number of peaks, presence of hyporeflective fissures at the base of the PED, structure of the RPE, presence of floating structures in the PED with maximum hyperreflectivity, amount and localization of hyperreflectivity in the PED and hyperreflectivity in the NIR images. RESULTS: In the 80 eyes of the PED group the mean PED height was 373.7± 197 µm and in the 18 eyes of the RIP group the mean PED height was higher (694.2± 284.3 µm, p < 0.0001). A difference was also seen in the number of peaks per PED (PED group 43%, RIP group 72%, p = 0.039) and in the hyperreflectivity in NIR images (PED group 68%, RIP group 94%, p = 0.033). There were no significant differences in the other morphological parameters. A classification into four types of PED was found by the parameters height and number of peaks. The PED type with a height > 350 µm and one peak (RIP 43%) developed tears more often (p = 0.001) than the PED type < 350 µm with one peak (RIP 0%, p = 0.001). A trend in the visual acuity over 156 weeks was seen: in PED types with heights > 350 µm there was a lower increase in the visual acuity than in PED types < 350 µm (rm ANOVA p = 0.18; ɛ HH = 0.88). Furthermore, in PED types > 350 µm with multiple peaks the total number of injections necessary was higher than in the other PED types (p = 0.032). CONCLUSION: Morphological parameters, such as PED height, number of peaks per PED in OCT images and hyperreflectivity in NIR images are prognostic factors for RPE tears in exudative AMD. The PED height and number of peaks per PED are useful for classification of PED in the daily routine.

Nanoparticulate CpG immunotherapy in RAO-affected horses: phase I and IIa study.

BACKGROUND: Recurrent airway obstruction (RAO), an asthma-like disease, is 1 of the most common allergic diseases in horses in the northern hemisphere. Hypersensitivity reactions to environmental antigens cause an allergic inflammatory response in the equine airways. Cytosine-phosphate-guanosine-oligodeoxynucleotides (CpG-ODN) are known to direct the immune system toward a Th1-pathway, and away from the pro-allergic Th2-line (Th2/Th1-shift). Gelatin nanoparticles (GNPs) are biocompatible and biodegradable immunological inert drug delivery systems that protect CpG-ODN against nuclease degeneration. Preliminary studies on the inhalation of GNP-bound CpG-ODN in RAO-affected horses have shown promising results. OBJECTIVES: The aim of this study was to evaluate the clinical and immunological effects of GNP-bound CpG-ODN in a double-blinded, placebo-controlled, prospective, randomized clinical trial and to verify a sustained effect post-treatment. ANIMALS AND METHODS: Twenty-four RAO-affected horses received 1 inhalation every 2 days for 5 consecutive administrations. Horses were examined for clinical, endoscopic, cytological, and blood biochemical variables before the inhalation regimen (I), immediately afterwards (II), and 4 weeks post-treatment (III). RESULTS: At time points I and II, administration of treatment rather than placebo corresponded to a statistically significant decrease in respiratory effort, nasal discharge, tracheal secretion, and viscosity, AaDO2 and neutrophil percentage, and an increase in arterial oxygen pressure. CONCLUSION AND CLINICAL IMPORTANCE: Administration of a GNP-bound CpG-ODN formulation caused a potent and persistent effect on allergic and inflammatory-induced clinical variables in RAO-affected horses. This treatment, therefore, provides an innovative, promising, and well-tolerated strategy beyond conventional symptomatic long-term therapy and could serve as a model for asthma treatment in humans.

Sociocognitive predictors of the intention of healthcare workers to receive the influenza vaccine in Belgian, Dutch and German hospital settings.

BACKGROUND: Influenza vaccination of healthcare workers (HCWs) is recommended to prevent the transmission of influenza to vulnerable patients. Nevertheless, vaccination coverage rates of HCWs in European countries have been low. AIM: To investigate the relative and combined strength of sociocognitive variables, from past research, theory and a qualitative study, in explaining the motivation of HCWs to receive the influenza vaccine. METHODS: An anonymous, online questionnaire was distributed among HCWs in hospital settings in Belgium, Germany and the Netherlands between February and April 2013. FINDINGS: Attitude and past vaccination uptake explained a considerable amount of variance in the intention of HCWs to receive the influenza vaccine. Moreover, low perceived social norms, omission bias, low moral norms, being older, having no patient contact, and being Belgian or Dutch (compared with German) increased the probability of having no intention to receive the influenza vaccine compared with being undecided about vaccination. High intention to receive the influenza vaccine was shown to be more likely than being undecided about vaccination when HCWs had high perceived susceptibility of contracting influenza, low naturalistic views, and lower motivation to receive the vaccine solely for self-protection. CONCLUSION: Country-specific interventions and a focus on different sociocognitive variables depending on the intention/lack of intention of HCWs to receive the influenza vaccine may be beneficial to promote vaccination uptake.

HaCaT cell line as a model system for vitamin D3 metabolism in human skin.

Synthesis and catabolism of calcitriol (1,25(OH)2D3) were studied using HaCaT cell line as a cell culture model. Our results indicate that stimulation of HaCaT cells with epidermal growth factor (EGF) or transforming growth factor-alpha (TGF-alpha) within 16 h just prior to reaching confluence amplified the production of calcitriol when calcidiol (3H-25OHD3) was used as a substrate. EGF- and TGF-alpha-induced (0.1-10 nM) 1-hydroxylation of 3H-25OHD3 was concentration-dependent but showed different kinetics. Synthesis of calcitriol induced by EGF was inversely related to the degree of cellular confluence. Stimulation by EGF was an actinomycin D- and cycloheximide-sensitive process. Independently of the growth factor used, the production of 3H-24R,25(OH)2D3 and the catabolism of 3H-1,25(OH)2D3 to 3H-1,24,25(OH)3D3 were unexpectedly low (< or = 5% and < or = 2%/), as compared to the amount of calcitriol generated. Exogenous addition of unlabeled 1,25(OH)2D3, 1,24R(OH)2D3, calcipotriol, or 24R,25(OH)2D3 at concentrations as low as 10(-11) M, potently inhibited the 3H-1,25(OH)2D3 production. These results suggest that EGF-treated HaCaT keratinocytes could serve for further studies of the vitamin D3 pathway and its relationship to proliferation and differentiation, but differences in calcitriol synthesis and catabolism from those in cultured primary keratinocytes or other cell lines must be considered.

UVB-induced conversion of 7-dehydrocholesterol to 1alpha,25-dihydroxyvitamin D3 in an in vitro human skin equivalent model.

We have previously shown that keratinocytes in vitro can convert biologically inactive vitamin D3 to the hormone calcitriol (1alpha,25-dihydroxyvitamin D3). This study was initiated to test whether the ultraviolet-B-induced photolysis of provitamin D3 (7-dehydrocholesterol), which results in the formation of vitamin D3, can generate calcitriol in an in vivo-like human skin equivalent model made of fibroblasts in a collagen matrix as the dermal component and keratinocytes as the epidermal component. Cultures were preincubated with increasing concentrations of 7-dehydrocholesterol (0.53-5.94 nmol per cm2 human skin equivalent) at 37 degrees C and irradiated with monochromatic ultraviolet B at wavelengths ranging from 285 to 315 nm (effective ultraviolet doses 7.5-45 mJ per cm2). In our in vitro model irradiation with ultraviolet B resulted in a sequential metabolic process with generation of previtamin D3 followed by the time-dependent formation of vitamin D3, 25-hydroxyvitamin D3, and ultimately calcitriol in the femtomolar range. Unirradiated cultures and irradiated cultures without keratinocytes generated no calcitriol. Irradiation of skin equivalents at wavelengths > 315 nm generated no or only trace amounts of calcitriol. The ultraviolet-B-triggered conversion of 7-dehydrocholesterol to calcitriol was strongly inhibited by ketoconazole indicating the involvement of P450 mixed function oxidases. The amount of calcitriol generated was dependent on the 7-dehydrocholesterol concentration, on wavelength, and on ultraviolet B dose. Hence, keratinocytes in the presence of physiologic concentrations of 7-dehydrocholesterol and irradiated with therapeutic doses of ultraviolet B may be a potential source of biologically active calcitriol within the epidermis.

Human keratinocyte line HaCaT metabolizes 1alpha-hydroxyvitamin D3 and vitamin D3 to 1alpha,25-dihydroxyvitamin D3 (calcitriol).

Cultured human keratinocytes have the property to hydroxylate exogenous 25-hydroxyvitamin D3 (25OHD3) at the C-1alpha position thus producing 1alpha,25-dihydroxyvitamin D3 (1alpha,25(OH)2D3). In this study we investigated whether keratinocytes can also hydroxylate vitamin D3 and one of its metabolites at the C-25 position. We could demonstrate that HaCaT keratinocytes can metabolize 1alpha-hydroxyvitamin D3 (1alpha-OHD3) and vitamin D3 to 1alpha,25(OH)2D3. Identification of the generated product as 1alpha,25(OH)2D3 was based on its elution pattern in two different high performance liquid chromatography systems, on its specific binding in a calf thymus receptor assay and on its gas chromatography-mass spectrometry characteristics. The hydroxylation of vitamin D3 to 1alpha,25(OH)2D3 was dose- and time-dependent. Bovine serum albumin added up to 1.5% (w/v) to the culture medium greatly increased the hydroxylation rates. These results show that HaCaT cells have the capacity to hydroxylate vitamin D3 at the C-1/25 positions. The generation of endogenous 1alpha,25(OH)2D3 from vitamin D3 within the skin may indicate a novel pathway which is of importance for the regulation of epidermal cell growth and differentiation.

Diagnostic value of urinary alanine aminopeptidase and N-acetyl-beta-D-glucosaminidase in comparison to alpha 1-microglobulin as a marker in evaluating tubular dysfunction in glomerulonephritis patients.

To estimate the diagnostic value of tubular parameters, the urinary alanine aminopeptidase (AAP), N-acetyl-beta-D-glucosaminidase (NAG) and the alpha(1)-microglobulin (a1M) of 150 patients with histologically proven glomerulonephritis (GN) were determined. In addition, the reabsorption rate of the proximal tubule and the fractional excretion of sodium, the free water clearance and the renal function were assessed by inulin and p-aminohippurate (PAH) clearance. Compared to healthy controls, urinary AAP, NAG and a1M were found significantly elevated in GN patients. Morphological tubular changes were confirmed by significant differences in urinary laboratory parameters. In patients with tubular atrophy, the diagnostic sensitivity and specificity were calculated as follows: AAP (0.94/0.35), NAG (0.75/0.59) and a1M (0.73/0.52). In patients showing tubular protein droplets, the values were 0.90/0.17 for AAP, 0.78/0.76 for NAG and 0.84/0.74 for a1M and in patients with interstitial fibrosis, the values were AAP (0.95/0.35), NAG (0.75/0. 46) and a1M (68/0.38). Urinary AAP, NAG and a1M reflect histologically proven tubulus alteration in GN, although in most cases, the renal function is still intact. AAP indicates very early tubular impairment and, in some cases, AAP is elevated although NAG and a1M are still within normal ranges. We suggest that the enzyme activities are useful in the diagnostics of early stages of the disease.

UVB-induced conversion of 7-dehydrocholesterol to 1 alpha,25-dihydroxyvitamin D3 (calcitriol) in the human keratinocyte line HaCaT.

We have previously shown that keratinocytes in vitro can convert biologically inactive vitamin D3 to the hormone calcitriol. The present study was initiated to test whether ultraviolet B (UVB)-induced photolysis of provitamin D3 (7-dehydrocholesterol, [7-DHC]) which results in the formation of vitamin D3 also leads to the generation of calcitriol in keratinocytes. Submerged monolayers of HaCaT keratinocytes were preincubated with 7-DHC (25 microM) at 37 degrees C and irradiated with monochromatic UVB at different wavelengths (effective UV-doses: 7.5-60 mJ/cm2), or a narrow-band fluorescent lamp Philips TL-01 (UVB-doses: 125-1500 mJ/cm2). Irradiation with both sources of UVB resulted in the generation of different amounts of previtamin D3 in our in vitro model followed by time-dependent isomerization to vitamin D3 and consecutive formation of calcitriol in the picomolar range. Unirradiated cultures or cultures exposed to wavelengths > 315 nm generated no or only trace amounts of calcitriol. The conversion of vitamin D3 generated after UVB irradiation to calcitriol is inhibited by ketoconazole indicating the involvement of P450 mixed function oxidases in this chemical reaction. The generation of calcitriol was wavelength- and UVB dose dependent and reached approximately 18-fold higher levels after irradiation at 297 nm than at 310 nm (effective UVB dose: 30 mJ/cm2). Hence, keratinocytes may be a potential source of biologically active calcitriol within epidermis, when irradiated with therapeutical doses of UVB.

Expression of vitamin D3 25-hydroxylase (CYP27) mRNA after induction by vitamin D3 or UVB radiation in keratinocytes of human skin equivalents--a preliminary study.

The presence of both 1alpha-hydroxylase activity and 25-hydroxylase activity is a biochemical prerequisite for the enzymatic generation of 1alpha,25(OH)2D3 from vitamin D3 in keratinocytes. In contrast to 1alpha-hydroxylase, however, activity of a 25-hydroxylase in keratinocytes has not previously been demonstrated. In this study, using RT-PCR we detected vitamin D3 25-hydroxylase mRNA in human keratinocytes. The expression of vitamin D3 25-hydroxylase mRNA in keratinocytes was identical to that of CYP27 expressed in mitochondria of human hepatoma HepG2 cells. CYP27 mRNA in keratinocytes is not constitutively expressed but is inducible both by vitamin D3 (780 nM) and by UVB radiation (300 nm, 30 mJ/cm2).

Demonstration of UVB-induced synthesis of 1 alpha,25-dihydroxyvitamin D3 (calcitriol) in human skin by microdialysis.

Cutaneous vitamin D(3) (VD(3)) is generated by UVB-induced photolysis of 7-dehydrocholesterol (7-DHC). VD(3) then undergoes sequential hydroxylation to calcidiol (25-OHD(3)) in the liver and to hormonally active calcitriol (1 alpha,25-(OH)(2)D(3)) in the kidney. Recently, we have described the epidermal VD(3) metabolic pathway by demonstrating the autochthonous formation of calcitriol in cultured keratinocytes. In this study we sought to determine whether photolysis of 7-DHC induced by irradiation of human skin with monochromatic UVB at 300 nm results in epidermal synthesis of calcitriol in vivo. Using a microdialysis technique we demonstrated that UVB irradiation results in a dose- and time-dependent increase in the calcitriol concentration in the extracellular fluid of UVB-irradiated skin. Topical treatment of skin with an ointment containing 2% ketoconazole immediately after irradiation suppressed UVB-induced intraepidermal calcitriol synthesis. This study demonstrates for the first time UVB-triggered synthesis of calcitriol in human skin in vivo. The link between UVB irradiation and synthesis of calcitriol in the skin may be of great importance for regulation of biological processes such as cell growth, differentiation, apoptosis and immunological reactions.

[Analysis of the NMR signal for biological information in spinal diagnosis]. / Analyse des NMR-Signals auf biologische Information in der Diagnostik der Wirbelsäule.

Discs of 23 patients and volunteers were examined for the purpose of obtaining T1 and T2-relaxation times. First of all, the signal characteristics of the surface coil were evaluated. The relaxation times of 100 discs were then measured by using standard spin echo sequences. There was a correlation between age and T2-values for healthy discs (R = -0.744). This was not found in case of degenerated discs. The mean value of T1 for healthy discs was found to be 825 ms. The results show a possibility of using relaxation measurements in routine diagnosis for the early identification of disc degeneration.

Determination of total cysteamine in human serum by a high-performance liquid chromatography with fluorescence detection.

A convenient, reliable and rapid method for determination of total cysteamine in human plasma by high-performance liquid chromatography with fluorescence detection is reported. This assay involves reduction of samples with dithiothreitol, derivatization of total cysteamine by addition of monobromobimane and protein precipitation by perchloric acid. The calibration curve was linear in the range 2-150 nmol ml-1 and the detection limit was 0.5 nmol ml-1. This method was successfully applied for a pharmacokinetic study of three cysteamine derivatives in healthy volunteers without any interference from coexisting substances.

Experimental lead toxicosis of raccoons (Procyon lotor).

Four pairs of raccoons were treated orally with the following doses of lead acetate (mg/kg; 5 days/week, for 8 weeks): 0 (control), 1, 2 and 4. In the six experimental animals, this treatment produced dose-dependent increases in blood lead, without clinical signs or changes in haematological parameters. After 8 weeks, the liver and kidney of all lead-treated animals and the calvarium and radius of those receiving doses of 2 and 4 mg/kg contained elevated concentrations of lead. Acid-fast inclusions were observed by light and electron microscopy in the kidneys of all raccoons receiving the two highest doses and in one animal receiving the lowest dose. Hepatic acid-fast inclusions were seen in only one animal (dose 4 mg/kg). No inclusions were seen in osteoclasts of the radius. It is suggested that the findings, which support earlier observations that raccoons are fairly resistant to lead, may be of value in studying interactions between lead exposure and oral vaccination of wildlife against rabies.