Intrinsically Safe Systems: Equivalency of International Standards Compared to U.S. Mining Approval Criteria.

This paper provides a suitability determination of international standards for evaluating electrical and electronic systems and line powered apparatus as an alternative to the Mine Safety and Health Administration (MSHA) criteria for two-fault intrinsic safety approval. The primary issue is to demonstrate that international equipment evaluation standards will provide at least the same level of protection for miners as the MSHA requirements. The secondary issue is to identify additional benefits that may be derived from the use of the "entity concept" in the approval process, such as potential cost savings, and an easier and quicker path for the introduction of new technology.

Drosophila Bcl-2 proteins participate in stress-induced apoptosis, but are not required for normal development.

Many developing tissues require programmed cell death (PCD) for proper formation. In mice and C. elegans, developmental PCD is regulated by the Bcl-2 family of proteins. Two bcl-2 genes are encoded in the Drosophila genome (debcl/dBorg1/Drob-1/dBok and buffy/dBorg2) and previous RNAi-based studies suggested a requirement for these in embryonic development. However, we report here that, despite the fact that many tissues in fruit flies are shaped by PCD, deletion of the bcl-2 genes does not perturb normal development. We investigated whether the fly bcl-2 genes regulate non-apoptotic processes that require caspases, but found these to be bcl-2 gene-independent. However, irradiation of the mutants demonstrates that DNA damage-induced apoptosis, mediated by Reaper, is blocked by buffy and that debcl is required to inhibit buffy. Our results demonstrate that developmental PCD regulation in the fly does not rely upon the Bcl-2 proteins, but that they provide an added layer of protection in the apoptotic response to stress.

Comparison of various doses of carbon 13-labeled aminopyrine for a carbon 13-labeled aminopyrine demethylation blood test in healthy dogs.

OBJECTIVE: To determine an optimal dose of carbon 13 ((13)C)-labeled aminopyrine for use in a (13)C-aminopyrine demethylation blood test in healthy dogs. ANIMALS: 9 adult dogs. PROCEDURES: Food was withheld from each dog for 12 hours. A 2-mL baseline blood sample was obtained from each dog and placed into an evacuated tube containing sodium heparin. Carbon 13-labeled aminopyrine was administered IV at doses of 1, 2, 5, or 10 mg/kg. Additional blood samples (2 mL) were obtained and placed into evacuated tubes containing sodium heparin 30, 45, 60, and 75 minutes after (13)C-aminopyrine administration. Hydrochloric acid was used to extract CO(2) from blood samples. The extracted gas was analyzed by fractional mass spectrometry to determine the percentage dose of (13)C administered as (13)C-aminopyrine and recovered in extracted gas (PCD). RESULTS: Gross evidence of clinical adverse effects was not detected in any dog after administration of (13)C-aminopyrine. The mean coefficient of variation (CV) for PCD was significantly lower than the mean CV for the summation of PCD values up to a given sampling time (CUMPCD). Mean PCD values among the 4 doses for each sample time were not significantly different. Administration of (13)C-aminopyrine at a dose of 2 mg/kg resulted in the lowest interindividual variability. CONCLUSIONS AND CLINICAL RELEVANCE: The PCD is superior to CUMPCD for the quantification of aminopyrine demethylation. Administration of (13)C-(13)C-aminopyrine at a dose of 2 mg/kg is appropriate for use in the (13)C-aminopyrine demethylation blood test in healthy dogs.

Kinetic analysis of demethylation of 13C-aminopyrine in healthy dogs.

OBJECTIVE: To describe the kinetics of demethylation of 13C-aminopyrine in healthy dogs for use in determining the most appropriate time for collection of blood samples for a 13C-aminopyrine demethylation blood test for evaluation of hepatic function. ANIMALS: 9 healthy dogs. PROCEDURES: A 2-mL baseline blood sample was collected into an evacuated heparinized tube, and 13C-aminopyrine was administered to each dog (2 mg/kg, IV). Additional 2-mL blood samples were collected 15, 30, 45, 60, 75, 90, 105, 120, 135, 150, 180, 240, 300, and 360 minutes after 13C-aminopyrine administration. The CO2 was extracted from blood samples by addition of a strong acid, and the percentage dose of 13CO2 (PCD) in the extracted gas was determined by fractional mass spectrometry. RESULTS: No dogs had gross evidence of adverse effects, and all had an increase in PCD after IV administration of 13C-aminopyrine. The PCD had the least variability among 5 variables used to evaluate hepatic demethylating capacity. Peak PCD was detected at 30 minutes in 1 dog, 45 minutes in 5 dogs, 60 minutes in 2 dogs, and 75 minutes in 1 dog. The mean PCD for the 9 dogs peaked at 45 minutes after 13C-aminopyrine administration. CONCLUSIONS AND CLINICAL RELEVANCE: PCD appears to be the preferable variable for evaluation of hepatic demethylating capacity. Intravenous administration of 13C-aminopyrine leads to a consistent increase in PCD. Mean PCD peaked 45 minutes after administration, suggesting that blood sample collection 45 minutes after 13C-aminopyrine administration may be appropriate for use in estimating hepatic demethylating capacity.

Effects of age and dietary beta-carotene on immunological variables in dogs.

beta-Carotene is a naturally occurring carotenoid reported to have health-promoting effects in several species. Advancing age is known to have a negative impact on various immune variables in several species. This study was conducted in order to assess the effect of age on immune response in dogs and to determine whether beta-carotene is able to reverse this age-associated decline. To test this hypothesis, young and old dogs (n = 36) were fed either a control diet or experimental diets containing supplemental beta-carotene for 2-month periods. Age significantly (P < .05) lowered CD4+ T cell populations (47.2% versus 33.7%; young-control versus old-control, respectively) and beta-carotene restored percent distributions in old dogs to nonsignificance versus younger controls (41.0%). T cell proliferation was lower in old dogs (30,254 +/- 2,248 versus 14,811 +/- 2,497 cCPM; young-control versus old-control, respectively; P < .05), and beta-carotene supplementation significantly improved responses in this age group (21,329 +/- 2,275 cCPM). Although B cell proliferation was depressed with age (17,967 +/- 1,384 versus 7,535 +/- 1,469 cCPM; young-control versus old-control, respectively; P < .05), beta-carotene supplementation improved B cell proliferation in young dogs (23,500 +/- 1,339 cCPM). Old dogs displayed lower delayed-type hypersensitivity test (DTH) responses versus younger controls to both phytohemagglutinin-P (PHA; 11.1 +/- 0.95 versus 7.57 +/- 1.15 mm; young-control versus old-control, respectively; P < .05) and sheep red blood cell (RBC; 9.12 +/- 0.62 versus 8.08 +/- 0.75 mm; young-control versus old-control, respectively; P < .10). beta-Carotene improved these responses, mostly within the first 24-48 hours after injection. In summary, older dogs have lower immunological responses compared with younger controls. beta-Carotene supplementation significantly restored immune responses in older dogs when compared with their age-matched controls and younger counterparts.

Ambulatory care-sensitive conditions: clinical outcomes and impact on intensive care unit resource use.

BACKGROUND: We identified risk factors and clinical outcomes associated with ambulatory care-sensitive conditions requiring intensive care unit (ICU) admission. METHODS: This prospective cohort study included 4,144 patients admitted to the medical ICU of an urban teaching hospital during a 3-year period. RESULTS: A total of 627 patients were classified as having ambulatory care-sensitive conditions (ie, potentially preventable ICU admissions). Black race, decreasing Acute Physiology and Chronic Health Evaluation II (APACHE II) score, younger age, female sex, and absence of immunodeficiency were independently associated with ambulatory care-sensitive conditions. Patients classified as having ambulatory care-sensitive conditions accounted for 2,006 ventilator days, 2,508 ICU days, and 5,392 hospital days. The hospital mortality rate was statistically lower for patients with ambulatory care-sensitive conditions than for patients without these conditions. Patients classified as having ambulatory care-sensitive conditions were also statistically more likely than other patients to lack health insurance and to sign out of the hospital against medical advice. CONCLUSION: Patients with ambulatory care-sensitive conditions account for a substantial portion of all admissions to the intensive care unit. These data suggest that interventions aimed at preventing such admissions could improve ICU bed use.

Transcription defines the embryonic domains of cis-regulatory activity at the Drosophila bithorax complex.

The extensive infraabdominal (iab) region contains a number of cis-regulatory elements, including enhancers, silencers, and insulators responsible for directing the developmental expression of the abdominal-A and Abdominal-B homeotic genes at the Drosophila bithorax complex. It is unclear how these regulatory elements are primed for activity early in embryogenesis, but the 100-kb intergenic region is subject to a complex transcriptional program. Here, we use molecular and genetic methods to examine the functional activity of the RNAs produced from this region and their role in cis regulation. We show that a subset of these transcripts demonstrates a distinct pattern of cellular localization. Furthermore, the transcripts from each iab region are discrete and the transcripts do not spread across the insulator elements that delineate the iab regions. In embryos carrying a Mcp deletion, the intergenic transcription pattern is disrupted in the iab4 region and the fourth abdominal segment is transformed into the fifth. We propose that intergenic transcription is required early in embryogenesis to initiate the activation of the Drosophila bithorax complex and define the domains of activity for the iab cis-regulatory elements. We also discuss a possible mechanism by which this may occur.

Biochemical and histopathological evaluation of changes in sled dog paw skin associated with physical stress and cold temperatures.

Abstract Twenty-six Alaskan sled dogs were used to study the biochemical and histopathological changes which occur when dog paws are exposed to cold temperatures and physical stress. They were separated into a running group of 20 dogs and a control group of six non-running dogs. Over 2 1/2 days, the running group ran in their natural environment for 170 miles and environmental parameters were recorded. Following the run, an 8-mm díameter skin biopsy specimen was taken from the lateral aspect of the right fore and hind paws of the running and non-running dogs. The skin was evaluated for histopathological changes and the présence of 2, 3-dinor thromboxane B2 (2, 3-dinor TxB2 ). No significant histopathological changes were noted in any of the biopsy specimens. Based on measured elevation of 2, 3-dinor TxB2 , the forepaws experienced more physical stress than the hind paws. Wet snow at higher environmental temperatures caused more paw stress than hard crusted snow at lower environmental temperatures. Resumen Se emplearon veintiséis perros trineo de Alaska para estudiar las alteraciones bioquimicas e histopatológicas ocurridas durante la exposición de las patas a las bajas temperaturas y al estrés fisico. Se dividieron entre un grupo de 20 perros corredores y un grupo control de seis perros no corredores. Durante dos días y medio el grupo de corredores corrió en su ambiente natural 170 millas. Durante la carrera se tomó una biopsia por punch de 8 mm del aspecto lateral de la pata derecha delantera y trasera de los perros corredores y no corredores. Se evaluaron las alteraciones histopatológicas cutáneas y la presencia de tromboxano B2 2, 3-dinor (2, 3-dinor TxB2 ). No se observaron alteraciones histopatológicas significativas en ninguna de las muestras de biopsia. Según la elevación detectada en 2.3-dinor TxB2 , las patas delanteras sufrieron un estrés fisico mayor que las traseras. La nieve húmeda en temperaturas ambientales elevadas causó un estrés mayor que la nieve dura en temperaturas ambientales más bajas. [Bradley, D.M., Swaim, S.F., Vaughn, D.M., Powers, R.D., McGuire, J.A., Reinhart, G.A., Burr, J., Swenson, R.A. Biochemical and histopathological evaluation of changes in sled dog paw skin associated with physical stress and cold temperatures. (Estudio bioquimico e histopatologico de las alteraciones en las patas de perros de trineo asociadas al estrés fisico y por las bajas temperaturas). Veterinary Dermatology 1996; 7: 203-208.] Résumé Vingt six chiens de traineau de l'Alaska fürent utilisés dans une étude évaluant les modifications biochimiques et histologiques survenant lorsque les pattes sont exposées à des températures froides et des stress physiques. lls fürent divisés en un groupe de vingt chiens de course et un groupe de six chiens ne courant pas. Après deux jours et demi, le groupe de course avait parcouru 170 miles dans son environnement naturel, dont les paramètres fürent enregistrés. Après la course, des biopsies de 8 mm de díamètre fürent prises sur les faces latérales des pattes antérieure et postérieure droites des chiens d'attelage et de ceux qui étaient restés au repos. L'évaluation de l'état cutané s'est faite sur les modifications histologiques et la présence de 2, 3-dinor thromboxane B2 (2, 3-dinor TxB2 ). Aucune modification histologique significative n'a été notée dans aucune des biopsies réalisées. Jugé sur l'élévation du 2, 3 TxB2 , les pattes antérieures subissent un stress physique supérieur aux pattes postérieures. La neige humide à temperatures plus élevées cause plus d'agression que la neige dure et crouteuse à des températures plus basses. [Bradley, D.M., Swaim, S.F., Vaughn, D.M., Powers, R.D., McGuire, J.A., Reinhart, G.A., Burr, J., Swenson, R.A. Biochemical and histopathological evaluation of changes in sled dog paw skin associated with physical stress and cold temperatures. (Evaluation des modifications biochimiques et histologiques induites par les stress physiques et le froid au niveau de la peau des pattes de chiens de traineau). Veterinary Dermatology 1996; 7: 203-208.] Zusammenfassung Sechsundzwanzig Alaska-Schlittenhunde wurde für eine Studie über biochemische und histopathologische Veränderungen herangezogen, die an den Pfotenballen auftreten, wenn sie kalten Temperaturen und physischem Streß ausgesetzt sind. Die Hunde wurden in eine Renngruppe von 20 Hunden und eine Kontrollgruppe von sechs Nicht-Rennhunden eingeteilt. Über einen Zeitraum von zweieinhalb Tagen rannte die Renngruppe in lhrer natürlichen Umgebung 170 Mellen, wobei die Umgebungsparamenter aufgezeichnet wurden. Nach dem Rennen wurden Biopsien mit einem Durchmesser von 8 mm von der Lateralseite der rechten Vorder-und Hinterpfote bei den Renn-und Nichtrennhunden entnommen. Die Haut wurde auf histopathologische Veränderungen und die Anwesenheit von 2, 3-dinor-Thromboxan BA (2, 3-dinor TxB2 ) untersucht. Es wurden keine signifikanten histopathologischen Veränderungen bei einer der Biopsien festgestellt. Auf der Basis der gemessenen Erhöhung von 2, 3-dinor TxB2 erfuhren die Vorderpfoten mehr physischen Streß als die Hinterpfoten. Nasser Schnee und höhere Umgebungstemperaturen verursachten mehr Pfotenstreß als harter, verkrusteter Schnee bei niedrigeren Umgebungstemperaturen. [Bradley, D.M., Swaim, S.F., Vaughn, D.M., Powers, R.D., McGuire, J.A., Reinhart, G.A., Burr, J., Swenson, R.A. Biochemical and histopathological evaluation of changes in sled dog paw skin associated with physical stress and cold temperatures (Biochemische und histopathologische Untersuchung von Hautveränderungen an den Pfoten von Schlittenhunden in Verbindung mit physischem Streß und Kälte). Veterinary Dermatology 1996; 7: 203-208.].