Heterogeneous addiction to transforming growth factor-beta signalling in recessive dystrophic epidermolysis bullosa-associated cutaneous squamous cell carcinoma.

BACKGROUND: Recessive dystrophic epidermolysis bullosa (RDEB) is associated with a high mortality rate due to the development of life-threatening, metastatic cutaneous squamous cell carcinoma (cSCC). Elevated transforming growth factor-beta (TGF-ß) signalling is implicated in cSCC development and progression in patients with RDEB. OBJECTIVES: To determine the effect of exogenous and endogenous TGF-ß signalling in RDEB cSCC with a view to assessing the potential of targeting TGF-ß signalling for RDEB cSCC therapy. METHODS: A panel of 11 patient-derived RDEB cSCC primary tumour keratinocyte cell lines (SCCRDEBs) were tested for their signalling and proliferation responses to exogenous TGF-ß. Their responses to TGF-ß receptor type-1 (TGFBR1) kinase inhibitors [SB-431542 and AZ12601011 (AZA01)] were tested using in vitro proliferation, clonogenicity, migration and three-dimensional invasion assays, and in vivo tumour xenograft assays. RESULTS: All SCCRDEBs responded to exogenous TGF-ß by activation of canonical SMAD signalling and proliferative arrest. Blocking endogenous signalling by treatment with SB-431542 and AZ12601011 significantly inhibited proliferation (seven of 11), clonogenicity (six of 11), migration (eight of 11) and invasion (six of 11) of SCCRDEBs. However, these TGFBR1 kinase inhibitors also promoted proliferation and clonogenicity in two of 11 SCCRDEB cell lines. Pretreatment of in vitro TGFBR1-addicted SCCRDEB70 cells with SB-431542 enhanced overall survival and reduced tumour volume in subcutaneous xenografts but had no effect on nonaddicted SCCRDEB2 cells in these assays. CONCLUSIONS: Targeting TGFBR1 kinase activity may have therapeutic benefit in the majority of RDEB cSCCs. However, the potential tumour suppressive role of TGF-ß signalling in a subset of RDEB cSCCs necessitates biomarker identification to enable patient stratification before clinical intervention.

Online fluorescence spectroscopy for the real-time evaluation of the microbial quality of drinking water.

We assessed the utility of online fluorescence spectroscopy for the real-time evaluation of the microbial quality of untreated drinking water. Online fluorimeters were installed on the raw water intake at four groundwater-derived UK public water supplies alongside existing turbidity sensors that are used to forewarn of the presence of microbial contamination in the water industry. The fluorimeters targeted fluorescent dissolved organic matter (DOM) peaks at excitation/emission wavelengths of 280/365 nm (tryptophan-like fluorescence, TLF) and 280/450 nm (humic-like fluorescence, HLF). Discrete samples were collected for Escherichia coli, total bacterial cell counts by flow cytometry, and laboratory-based fluorescence and absorbance. Both TLF and HLF were strongly correlated with E. coli (ρ = 0.71-0.77) and total bacterial cell concentrations (ρ = 0.73-0.76), whereas the correlations between turbidity and E. coli (ρ = 0.48) and total bacterial cell counts (ρ = 0.40) were much weaker. No clear TLF peak was observed at the sites and all apparent TLF was considered to be optical bleed-through from the neighbouring HLF peak. Therefore, a HLF fluorimeter alone would be sufficient to evaluate the microbial water quality at these sources. Fluorescent DOM was also influenced by site operations such as pump start-up and the precipitation of cations on the sensor windows. Online fluorescent DOM sensors are a better indicator of the microbial quality of untreated drinking water than turbidity and they have wide-ranging potential applications within the water industry.

Terrestrial water load and groundwater fluctuation in the Bengal Basin.

Groundwater-level fluctuations represent hydraulic responses to changes in groundwater storage due to aquifer recharge and drainage as well as to changes in stress that include water mass loading and unloading above the aquifer surface. The latter 'poroelastic' response of confined aquifers is a well-established phenomenon which has been demonstrated in diverse hydrogeological environments but is frequently ignored in assessments of groundwater resources. Here we present high-frequency groundwater measurements over a twelve-month period from the tropical, fluvio-deltaic Bengal Aquifer System (BAS), the largest aquifer in south Asia. The groundwater level fluctuations are dominated by the aquifer poroelastic response to changes in terrestrial water loading by processes acting over periods ranging from hours to months; the effects of groundwater flow are subordinate. Our measurements represent the first direct, quantitative identification of loading effects on groundwater levels in the BAS. Our analysis highlights the potential limitations of hydrogeological analyses which ignore loading effects in this environment. We also demonstrate the potential for employing poroelastic responses in the BAS and across other tropical fluvio-deltaic regions as a direct, in-situ measure of changes in terrestrial water storage to complement analyses from the Gravity and Climate Experiment (GRACE) mission but at much higher resolution.

Hydrogeological typologies of the Indo-Gangetic basin alluvial aquifer, South Asia.

The Indo-Gangetic aquifer is one of the world's most important transboundary water resources, and the most heavily exploited aquifer in the world. To better understand the aquifer system, typologies have been characterized for the aquifer, which integrate existing datasets across the Indo-Gangetic catchment basin at a transboundary scale for the first time, and provide an alternative conceptualization of this aquifer system. Traditionally considered and mapped as a single homogenous aquifer of comparable aquifer properties and groundwater resource at a transboundary scale, the typologies illuminate significant spatial differences in recharge, permeability, storage, and groundwater chemistry across the aquifer system at this transboundary scale. These changes are shown to be systematic, concurrent with large-scale changes in sedimentology of the Pleistocene and Holocene alluvial aquifer, climate, and recent irrigation practices. Seven typologies of the aquifer are presented, each having a distinct set of challenges and opportunities for groundwater development and a different resilience to abstraction and climate change. The seven typologies are: (1) the piedmont margin, (2) the Upper Indus and Upper-Mid Ganges, (3) the Lower Ganges and Mid Brahmaputra, (4) the fluvially influenced deltaic area of the Bengal Basin, (5) the Middle Indus and Upper Ganges, (6) the Lower Indus, and (7) the marine-influenced deltaic areas.

L'aquifère de l'Indus et du Gange est une des ressources en eau transfrontalière la plus importante au monde et un des aquifères le plus exploité au monde. Pour mieux comprendre le système aquifère, des typologies ont été caractérisées pour cet aquifère ; elles intègrent pour la première fois un jeu de données disponibles sur l'ensemble du bassin de l'Indus et du Gange à une échelle transfrontalière, et apportent une conceptualisation alternative de ce système aquifère. Traditionnellement considéré et cartographié comme un simple aquifère homogène aux propriétés aquifères similaires et comme une ressource d'eau souterraine à l'échelle transfrontalière, les typologies mettent en évidence des différences significatives spatiales de la recharge, de la perméabilité, de la capacité de stockage et de la chimie des eaux souterraines sur l'ensemble du système aquifère à une échelle transfrontalière. Ces changements sont systématiques coïncidant aux changements à large échelle de la sédimentologie de l'aquifère alluvial du Pléistocène et de l'Holocène, du climat et des pratiques récentes d'irrigation. Sept typologies de l'aquifère sont présentées, chacune ayant un ensemble distinct de défis et d'opportunités pour le développement des eaux souterraines et une résilience différente à l'exploitation et au changement climatique. Les sept typologies sont: (1) la marge de piedmont, (2) Le haut Indus et le Ganges moyen supérieur, (3) le Ganges inférieur et le Brahmapoutre moyen, (4) la zone deltaïque du bassin du Bengale sous influence fluviale, (5) l'Indus moyen et le Ganges supérieur, (6) l'Indus inférieur, et (7) la zone deltaïque sous influence marine.

El acuífero Indo-Gangético es uno de los recursos hídricos transfronterizos más importantes y el acuífero más explotado del mundo. Para comprender mejor el sistema acuífero, por primera vez se han caracterizado tipologías para el acuífero, integrando los conjuntos de datos existentes a través de la cuenca hidrográfica Indo-Ganges a una escala transfronteriza, y proporcionando una conceptualización alternativa de este sistema acuífero. Tradicionalmente consideradas y cartografiadas como un solo acuífero homogéneo de propiedades acuíferas y recursos de agua subterránea comparables a escala transfronteriza, las tipologías iluminan diferencias espaciales significativas en la recarga, permeabilidad, almacenamiento y química del agua subterránea a través del sistema acuífero a esta escala transfronteriza. Estos cambios son mostrados por ser sistemáticos, coincidentes con cambios en gran escala en la sedimentología del acuífero aluvial del Pleistoceno y del Holoceno, en el clima y en las prácticas recientes de riego. Se presentan siete tipologías del acuífero, cada una con un conjunto distinto de desafíos y oportunidades para el desarrollo del agua subterránea y una diferente resiliencia a la extracción y al cambio climático. Las siete tipologías son: (1) el margen del piedemonte, (2) el Indus superior y el Ganges superior-medio, (3) el Ganges inferior y el Brahmaputra medio, (4) el área deltaica fluvialmente influenciada de la cuenca de Bengala, (5) el Ganges superior, (6) el Indo Inferior, y (7) las áreas deltaicas con influencia marina.

O aquífero do Indo-Gangético é um dos recursos hídricos transfronteiriços mais importantes do mundo, e o mais explorado. Para melhor entender o sistema aquífero, tipologias foram caracterizadas para o aquífero, que integram pela primeira vez bancos de dados existentes sobre a bacia de abastecimento Indo-Gangética em uma escala transfornteiriça, e fornecem uma conceptualização alternativa desse sistema aquífero. Tradicionalmente considerado e mapeado como um aquífero homogêneo de propriedades aquíferas comparáveis e recursos subterrâneos em escala transfronteiriça, as tipologias elucidam diferenças espaciais significantes na recarga, permeabilidade, armazenamento, e química das águas subterrâneas pelo aquífero nessa escala transfronteiriça. Essas mudanças aparentam ser sistemáticas, concorrentes com mudanças em larga escala na sedimentologia do aquífero aluvial do Pleistoceno e Holoceno, clima e práticas recentes de irrigação. Sete tipologias do aquífero são apresentadas, cada uma tendo conjuntos de desafios e oportunidades distintos para o desenvolvimento das águas subterrâneas e uma resiliência diferente nas mudanças de extração e clima. As sete tipologias são: (1) a margem piemonte, (2) O Alto Indo e o Alto-médio Ganges, (3) O Baixo Ganges e o Médio Brahmaputra, (4) a área deltaica influenciada fluvialmente da Bacia de Bengala, (5) o Médio Indo e o Alto Ganges, (6) o Baixo Indo, e (7) as áreas deltaicas com influencia marinha.

Three approaches to time valuation in recreation demand: a study of the Snake River recreation area in eastern Washington.

Three travel cost models are used to estimate non-fishing recreation demand at the Snake River reservoirs recreation area in eastern Washington. The opportunity cost of time is specified in the "traditional" and McConnell-Strand models as a fraction of the exogenous market wage rate and in the two-step decision model as a function of socioeconomic attributes of the recreationists. Benefits per person per trip were $90, $35, and $46 respectively, for the three models. Boaters visit the site more than three times as often as non-boaters resulting in higher annual benefits for boaters.

25-hydroxyvitamin D, insulin-like growth factor-I, and bone mineral accrual during growth.

CONTEXT: The extent to which 25-hydroxyvitamin D [25(OH)D] and IGF-I influence bone mineral content (BMC) accrual from early to mid-puberty is unclear. OBJECTIVE, SETTING, AND PARTICIPANTS: This study sought to determine relationships among 25(OH)D, IGF-I, and BMC in community-dwelling prepubertal females (n = 76; aged 4-8 yr at baseline) over a period of up to 9 yr. DESIGN: The hypothesis that changes in IGF-I vs. 25(OH)D are more strongly associated with BMC accrual was formulated after data collection. 25(OH)D and IGF-I were log-transformed and further adjusted using two-way ANOVA for differences in season and race. Linear mixed modeling (including a random subject-specific intercept and a random subject-specific slope on age) was employed to analyze the proportion of variance the transformed 25(OH)D and IGF-I variables explained for the bone outcomes. RESULTS: IGF-I was more strongly associated with BMC accrual than 25(OH)D at the total body (R(2) = 0.874 vs. 0.809), proximal femur (R(2) = 0.847 vs. 0.771), radius (R(2) = 0.812 vs. 0.759), and lumbar spine (R(2) = 0.759 vs. 0.698). The rate of BMC accrual was positively associated with changes in IGF-I but negatively associated with 25(OH)D. When IGF-I and 25(OH)D were included in the same regression equation, 25(OH)D did not have a significant predictive effect on BMC accrual above and beyond that of IGF-I. CONCLUSIONS: These prospective data in early adolescent females indicate that both 25(OH)D and IGF-I have a significant impact on bone mineral accrual; however, the positive association of IGF-I and BMC accrual is greater than the negative association of 25(OH)D and BMC accrual.

Lysine intake affects gene expression of anabolic hormones in Atlantic salmon, Salmo salar.

Nutritional factors influence regulation of the growth hormone (GH) and the insulin-like growth factor (IGF) system in fish, but so far there are no published studies describing how single indispensable amino acids influence these systems. Therefore, the present study aimed to test whether lysine (Lys) intake at low (LL=2.85 g/16 gN), medium (ML=4.91 g/16 gN) and high levels (HL=9.19 g/16 gN) affected the expression of genes related to the GH-IGF system (i.e. GH receptor, GH-R, IGF-I, IGF-II, IGF binding protein 1, IGFBP-1, IGF-I receptor IGF-IR) in Atlantic salmon during seawater growth phase. Salmon fed the HL diet significantly up-regulated hepatic IGF-I mRNA level by a factor of 2.2 as compared to those with medium Lys intake. In addition a significant up-regulation of 2.7-fold in muscle IGF-II mRNA was present. Low Lys intake decreased the nitrogen deposition and muscle protein accretion in fish and significantly down-regulated hepatic IGFBP-1 as well as muscle GH-R and IGF-II, as compared to those fed the ML diet. mRNA of IGF-IR on the other hand was not affected by Lys intake. High Lys intake resulted in a 7-fold up-regulation of muscle IGF-II mRNA level as compared to low Lys intake, and thus might be an important local anabolic regulator in fast muscle tissue. The single indispensable amino acid Lys indeed affected signalling through the genes of IGF-I, IGFBP-1 in hepatic tissue and GH-R, IGF-II in fast muscle in Atlantic salmon. Concomitantly the higher Lys intake increased nitrogen deposition to a certain level.

Calpain 3/p94 is not involved in postmortem proteolysis.

Studies on the correlation between expression and/or autolysis of calpain and postmortem proteolysis in muscle have provided conflicting evidence regarding the possible role of calpain 3 in postmortem tenderization of meat. Thus, the objective of this research was to test the effect of postmortem storage on proteolysis and structural changes in muscle from normal and calpain 3 knockout mice. Knockout mice (n = 6) were sacrificed along with control mice (n = 6). Hind limbs were removed and stored at 4 degrees C; muscles were dissected at 0, 1, and 3 d postmortem and subsequently analyzed individually for degradation of desmin. Pooled samples for each storage time and mouse type were analyzed for degradation of nebulin, dystrophin, vinculin, and troponin-T. In a separate experiment, hind-limb muscles from knockout (n = 4) and control mice (n = 4) were analyzed for structural changes at 0 and 7 d postmortem using light microscopy. As an index of structural changes, fiber detachment, cracked or broken fibers, and the appearance of space between sarcomeres were quantified. Cumulatively, the results of the first experiment indicated that postmortem proteolysis of muscle occurred similarly in control and in calpain 3 knockout mice. Desmin degradation did not differ (P > 0.99), and there were no indications that degradation of nebulin, dystrophin, vinculin, and troponin-T were affected by the absence of calpain 3 in postmortem muscle. Structural changes were affected by time postmortem (P < 0.05), but not by the absence of calpain 3 from the muscles. In conclusion, these results indicate that calpain 3 plays a minor role, if any, in postmortem proteolysis in muscle.

Retained common-duct stones after open cholecystectomy and duct exploration in children.

A retrospective study was performed of 250 patients with cholelithiasis treated at the Royal Children's Hospital, (RCH) Melbourne, over 25 years by open operation; 32 (12.8%) had proven choledocholithiasis on either preoperative imaging, operative cholangiography (OpCG), or postoperative investigation. A further 3 had underlying congenital biliary abnormalities and were excluded from further study. Thirty-one of the 32 were explored at open operation, 27 after OpCG and 4 on clinical grounds. One retained common-bile-duct (CBD) stone was undetected until the postoperative period (1/250, 0.25%). Seven ducts were not cleared, giving a duct exploration failure rate of 22.6% (7/31). All 8 retained CBD stones were identified in the early postoperative period and managed with a variety of techniques, including endoscopic retrograde cholangio-pancreatography (ERCP). The incidence of retained stones after open CBD exploration was high (22.6%), and can be attributed to difficulties in operative technique dealing with the smaller paediatric CBD. In addition, haemolytic disease seems to induce a propensity for choledocholithiasis. Given the small numbers presenting with cholelithiasis to RCH (10 per year), it is suggested that a selective approach to CBD exploration is appropriate in children. With the increasing use of laparoscopic cholecystectomy in children and the inherent technical difficulties of laparoscopic operative cholangiography, ERCP may offer an alternative solution in dealing with CBD stones rather than open or laparoscopic CBD exploration.

Ultrastructural changes during aging in M. longissimus thoracis from moose and reindeer.

Game meat is commonly consumed in Europe but few studies have examined the quality related parameters. In this study we examined the changes in ultrastructure at four times postmortem in M. longissimus from moose (Alces alces) and reindeer (Rangifer tarandus tarandus). The moose were slaughtered during a hunt and reindeer by Swedish standard practices for this semi-domestic animal. Ultrastructural changes occurring in all animals included separation of the sarcolemma from myofibrils, I band breaks, and cytoskeleton breaks; however both I band breaks and cytoskeletal breaks were less common in moose and reindeer than values reported for sheep and beef. Fiber area in the longissimus thoracis muscle was approximately 3270 µm(2) for moose and 1170 µm(2) for reindeer indicating that the tenderness of reindeer meat may be largely determined by fiber size.

Evidence against the non-enzymatic calcium theory of tenderization.

The objective of the present study was to determine whether variation in the tenderization of lamb longissimus could be attributed to variations in the rise in free calcium postmortem and sarcomere lengthening post rigor. The longissimus muscle of 10 crossbred lambs (Romney×Coopworth) was sampled at 1 and 7 days postmortem for determination of MIRINZ shear force, myofibrillar fragmentation index (MFI), sarcomere length, free calcium, and proteolysis of troponin-T. Despite considerable variation in tenderness and tenderization of the muscles, sarcomere lengthening was not observed. The concentration of free calcium at 7 days postmortem correlated significantly with the MFI (r=0.640; P<0.05) and tended to correlate with the shear force (r=-0.596; P<0.1) and degradation of troponin-T (r=0.625; P<0.1). Degradation of troponin-T was significantly correlated with tenderization (r=0.664; P<0.05). Troponin-T is a calpain substrate, but reportedly is not degraded through a direct effect from calcium. The present results, therefore, suggest that the variation in free calcium in postmortem muscle affects tenderization through an effect on the calpain system and not through a direct effect of calcium on myofibrillar proteins. Consequently, the results of this study do not support the (calcium) theory that calcium directly affects tenderization.

High-pressure effects on lysosome integrity and lysosomal enzyme activity in bovine muscle.

This study was conducted to determine whether the application of high hydrostatic pressure could modify the enzymatic activity and membrane integrity of lysosomes in muscle. Several combinations of pressure (0-600 MPa) and time (0-300 s) were applied to two types of samples: purified enzymes (cathepsin D and acid phosphatase) in buffer solution and intact muscle (biceps femoris). The enzymes studied showed varying degrees of susceptibility depending on the level of pressure, holding time, and environment. Acid phosphatase activity was minimally affected by pressure in buffer solution, whereas cathepsin D was modulated significantly by the pressure and time applied. The activities of the enzymes extracted from meat increased with pressure. The cytochemical observations showed the presence of primary and secondary lysosomes in muscles. After pressurization, the membrane integrity of the lysosomes was modified. A correlation could be established between lysosomal enzymatic activities and the lysosome membrane breakdown.

mRNA levels of dipeptidyl peptidase IV decrease during intestinal adaptation.

BACKGROUND: Glucagon-like peptide 2 (GLP-2) has recently been shown to be a potent enterotrophic factor that may mediate mucosal hyperplasia during intestinal adaptation. The intestinal brush-border protease dipeptidyl peptidase IV (DPP IV) cleaves GLP-2 to an inactive form. It has been postulated that DPP IV activity limits the enterotrophic activity of GLP-2 in rats and humans. Massive small bowel resection (MSBR) in rats is an animal model of intestinal adaptation that has been used successfully to characterize factors involved in the modulation of adaptation. METHODS: Total RNA was extracted from normal terminal ileum or terminal ileum post-MSBR from Sprague-Dawley rats which were sacrificed 2, 4, and 7 days postresection. A partial rat DPP IV clone was isolated by reverse transcription polymerase chain reaction, and Northern blot analysis of rat DPP IV mRNA levels in normal small bowel and small bowel post-MSBR was performed. RESULTS: Within normal small bowel, DPP IV mRNA levels were greatest in the terminal ileum; levels in the duodenum and jejunum were approximately 50% of those in the terminal ileum. DPP IV mRNA levels decreased in terminal ileum post-MSBR 2, 4, and 7 days after resection. CONCLUSION: The decreased DPPIV gene expression suggests a novel mechanism by which the effects on mucosal growth of GLP-2 may be further enhanced, and further that GLP-2 may be a more useful therapeutic agent in humans than currently anticipated.

Effects of postmortem storage on the ultrastructure of the endomysium and myofibrils in normal and callipyge longissimus.

These experiments were conducted to examine ultrastructural changes in longissimus from normal and callipyge lamb during 14 d of postmortem storage at 4 degrees C. Six crossbred ewe lambs (1/2 Dorset x 1/2 Romanov) were grain-fed and slaughtered at approximately 250 d of age. Leg conformation score was the basis for classifying carcasses into normal and callipyge. The normal and callipyge longissimus had mean Warner-Bratzler shear force of 2.8 (2.7, 2.4, and 3.4) and 9.0 (12.2, 6.9, and 7.9) kg, respectively, after 14 d of postmortem storage. The results of transmission electron microscopy demonstrated ultrastructural changes, including sarcolemma detachment, loss of myofibril lateral attachments, and I-band breaks in normal longissimus. Detachment of sarcolemma from myofibrils occurred in both phenotypes, but it was delayed by several days in callipyge longissimus. Thus, the sarcolemma detachment seems not to contribute significantly to postmortem tenderization. The endomysium of both phenotypes did not change with postmortem storage. In normal longissimus, the percentage of fractured I-bands increased from 0% at d 1 to 11% at d 3 (P<.05) and did not change between 3 and 14 d (15%) postmortem (P>.05). However, postmortem storage did not affect (0 to 3%) the frequency of the I-band breaks in the callipyge longissimus (P>.05). Therefore, the break in the I-band region in postmortem muscle is a change that is associated with postmortem tenderization. We conclude that the major factor responsible for the toughness of meat from callipyge longissimus is the postmortem stability of myofibrils.

Tissue distribution of rat glucagon receptor and GLP-1 receptor gene expression.

The regulation of glucose metabolism by glucagon and GLP-1 is well established, but novel functions for these and other proglucagon-derived peptides are less well defined. This paper highlights the diversity of both GLP-1 and glucagon activity by studying the tissue distribution of glucagon and GLP-1 receptor gene expression by both Southern blot analysis of RT-PCR products and nuclease protection assays. By Southern blot analysis of RT-PCR products, GLP-1 receptor mRNA was detected in lung, hypothalamus, hippocampus, cerebral cortex, kidney, pancreas, and throughout the gastrointestinal tract. Glucagon receptor expression was detected in liver, kidney, spleen, thymus, adrenal glands, pancreas, cerebral cortex, lung, and throughout the gastrointestinal tract. Nuclease protection assay revealed glucagon receptor expression to be highest in liver and kidney, whereas GLP-1 receptor expression was only detected by protection assay in lung, stomach, and large bowel. Despite previous evidence that other receptors for proglucagon-derived peptides may exist, no evidence of novel receptors or multiple isoforms of the glucagon and GLP-1 receptors was found, indicating that the two cloned receptors may mediate all the effects of proglucagon-derived peptides, or that novel receptors may share less homology with the glucagon and GLP-1 receptors than previously anticipated.

Driver stress and performance on a driving simulator.

Effects of stress on driving performance can depend on the nature of driver's stress reactions and on the traffic environment. In an experimental study, we assessed multiple dimensions of vulnerability to driver stress by a questionnaire that was validated in previous field studies and related those dimensions to performance on a driving simulator. Results were broadly consistent with prediction. A dimension of habitual dislike of driving was associated with reduced control skills, greater caution, and disturbance of moods. A measure of aggressive driving predicted more frequent and more error-prone overtaking, which are effects attributed to the use of confrontive coping strategies in interaction with other vehicles. An alertness measure predicted speed of reaction to pedestrian hazards. This research has practical applications for system design, automated monitoring of driver performance, selection and assessment of drivers, and training.

Vertebral osteomyelitis in an infant presenting with a posterior mediastinal mass.

A rare case of vertebral osteomyelitis and paravertebral abscess that presented as a posterior mediastinal tumour with airway compression in a 7-week-old baby is presented. The differential diagnosis and the recommended treatment are discussed.

Association of muscle-specific kinase MuSK with the acetylcholine receptor in mammalian muscle.

During synaptogenesis at the neuromuscular junction, a neurally released factor, agrin, causes the clustering of acetylcholine receptors (AChRs) in the muscle membrane beneath the nerve terminal. Agrin acts through a specific receptor which is thought to have a receptor tyrosine kinase, MuSK, as one of its components. In agrin-treated muscle cells, both MuSK and the AChR become tyrosine phosphorylated. To determine how the activation of MuSK leads to AChR clustering, we have investigated their interaction in cultured C2 myotubes. Immunoprecipitation experiments showed that MuSK is associated with the AChR and that this association is increased by agrin treatment. Agrin also caused a transient activation of the AChR-associated MuSK, as demonstrated by MuSK phosphorylation. In agrin-treated myotubes, MuSK phosphorylation increased with the same time course as phosphorylation of the beta subunit of the AChR, but declined more quickly. Although both herbimycin and staurosporine blocked agrin-induced AChR phosphorylation, only herbimycin inhibited the phosphorylation of MuSK. These results suggest that although agrin increases the amount of activated MuSK that is associated with the AChR, MuSK is not directly responsible for AChR phosphorylation but acts through other kinases.

Fish muscle cytoskeleton integrity is not dependent on intact thin filaments.

Striated muscle cytoskeleton was studied by ultrastructure and electrophoresis. Treatment of sea bass white muscle myofibrils and glycerinated fibres with calpain caused disruption of costameres, intermediate filaments, and Z-line, without altering sarcomeres. V8 protease also caused loss of costameres and Z-line, and disrupted sarcomeres without affecting the intermediate filaments. Recombinant lipase caused loss of Z-lines and also sarcolemma detachment, without changing sarcomeres or intermediate filaments. DNase-1 removed thin filaments and partially removed Z-lines while leaving intact the sarcolemma attachments and intermediate filaments. Calpain, V8 protease, lipase and DNase-1 treatments induced extensive loss of alpha-actinin from the Z-line, which could be related to titin cleavage (calpain, V8), phosphoinositide hydrolysis (lipase), and actin depolymerisation (DNase-1). These results show that the cytoskeletal components are independent of intact thin filaments.

Age and gender differences in perceived accident likelihood and driver competences.

Road traffic accident involvement rates show clear age and gender differences which may in part be accounted for by differences in risk perception and perceptions of driving competence. The present study extends and replicates that of Matthews and Moran (1986). Young (18-30 years) and older (45-60 years) male and female drivers responded to a questionnaire on perceived accident risk and driving competence (judgment and skill) with respect to themselves and four target groups, and also rated a series of videotaped driving sequences with respect to likelihood of accident occurrence and perceived driving competence. Results showed that effects of rater characteristics were generally confined to the questionnaire. Younger males were perceived as most likely to experience an accident and were judged to be lower than other groups in driving competence. Younger groups showed little bias against older groups and vice versa, but gender-related bias was apparent. The findings of Matthews and Moran were generally confirmed. The results are discussed with reference to four main issues: (1) demographic bias effects--which are generally weak; (2) stereotyping on the basis of gender and/or age of driver; (3) group-specific bias; (4) self-appraisal bias.