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1.
Diabetologia ; 55(11): 3094-103, 2012 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-22872212

RESUMEN

AIMS/HYPOTHESIS: Glucose-dependent insulinotropic polypeptide (GIP) is an enteroendocrine hormone that promotes storage of glucose and fat. Its secretion from intestinal K cells is triggered by nutrient ingestion and is modulated by intracellular cAMP. In view of the proadipogenic actions of GIP, this study aimed to identify pathways in K cells that lower cAMP levels and GIP secretion. METHODS: Murine K cells purified by flow cytometry were analysed for expression of G(αi)-coupled receptors by transcriptomic microarrays. Somatostatin and cannabinoid receptor expression was confirmed by quantitative RT-PCR. Hormone secretion in vitro was measured in GLUTag and primary murine intestinal cultures. cAMP was monitored in GLUTag cells using the genetically encoded sensor Epac2-camps. In vivo tolerance tests were performed in cannulated rats. RESULTS: Purified murine K cells expressed high mRNA levels for somatostatin receptors (Sstrs) Sstr2, Sstr3 and Sstr5, and cannabinoid receptor type 1 (Cnr1, CB1). Somatostatin inhibited GIP and glucagon-like peptide-1 (GLP-1) secretion from primary small intestinal cultures, in part through SSTR5, and reduced cAMP generation in GLUTag cells. Although the CB1 agonist methanandamide (mAEA) inhibited GIP secretion, no significant effect was observed on GLP-1 secretion from primary cultures. In cannulated rats, treatment with mAEA prior to an oral glucose tolerance test suppressed plasma GIP but not GLP-1 levels, whereas the CB1 antagonist AM251 elevated basal GIP concentrations. CONCLUSIONS/INTERPRETATION: GIP release is inhibited by somatostatin and CB1 agonists. The differential effects of CB1 ligands on GIP and GLP-1 release may provide a new tool to dissociate secretion of these incretin hormones and lower GIP but not GLP-1 levels in vivo.


Asunto(s)
Colon/metabolismo , Polipéptido Inhibidor Gástrico/metabolismo , Intestino Delgado/metabolismo , Receptor Cannabinoide CB1/metabolismo , Receptores de Somatostatina/metabolismo , Animales , Colon/citología , AMP Cíclico/metabolismo , Células Enteroendocrinas/citología , Células Enteroendocrinas/metabolismo , Péptido 1 Similar al Glucagón/metabolismo , Incretinas/metabolismo , Intestino Delgado/citología , Masculino , Ratones , Ratones Endogámicos C57BL , Cultivo Primario de Células , ARN Mensajero/metabolismo , Ratas , Ratas Sprague-Dawley , Receptor Cannabinoide CB1/genética , Receptores de Somatostatina/genética
3.
Radiat Meas ; 26(6): 863-80, 1996 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11540519

RESUMEN

We present an overview of the Long Duration Exposure Facility (LDEF) induced activation measurements. The LDEF, which was gravity-gradient stabilized, was exposed to the low Earth orbit (LEO) radiation environment over a 5.8 year period. Retrieved activation samples and structural components from the spacecraft were analyzed with low and ultra-low background HPGe gamma spectrometry at several national facilities. This allowed a very sensitive measurement of long-lived radionuclides produced by proton- and neutron-induced reactions in the time-dependent, non-isotropic LEO environment. A summary of major findings from this study is given that consists of directionally dependent activation, depth profiles, thermal neutron activation, and surface beryllium-7 deposition from the upper atmosphere. We also describe a database of these measurements that has been prepared for use in testing radiation environmental models and spacecraft design.


Asunto(s)
Berilio , Neutrones , Protones , Radioisótopos , Vuelo Espacial/instrumentación , Nave Espacial/instrumentación , Aluminio/efectos de la radiación , Anisotropía , Bases de Datos Factuales , Medio Ambiente Extraterrestre , Metales Pesados , Análisis de Activación de Neutrones , Radiactividad , Investigación , Actividad Solar , Espectrometría gamma/métodos
4.
Br J Oral Maxillofac Surg ; 37(4): 255-8, 1999 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-10475644

RESUMEN

We describe a technique for obtaining lingual access for the insertion of a wide metal retractor to protect the lingual nerve from accidental damage during third molar surgery. We also report an audit of a single practice over a 20-year period using the technique described. The approach involves raising soft tissues on the lingual side of the lower third molar tooth to allow insertion of a broad Hovell's lingual retractor. We conclude that raising lingual tissues to form a wide tension-free flap and inserting a specifically designed retractor does not increase the incidence of lingual nerve morbidity. Indeed, the overall incidence of lingual nerve damage was particularly low compared with those in other published series.


Asunto(s)
Tercer Molar/cirugía , Extracción Dental/métodos , Adolescente , Adulto , Distribución por Edad , Mejilla , Auditoría Odontológica , Femenino , Humanos , Incidencia , Complicaciones Intraoperatorias/epidemiología , Complicaciones Intraoperatorias/etiología , Complicaciones Intraoperatorias/prevención & control , Traumatismos del Nervio Lingual , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Distribución por Sexo , Colgajos Quirúrgicos , Lengua , Extracción Dental/efectos adversos , Extracción Dental/instrumentación
5.
Br J Oral Maxillofac Surg ; 38(5): 537-8, 2000 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11010790

RESUMEN

We found an incidence of 6% (5/81) of traumatic neuroma after section of the great auricular nerve during operations on the parotid gland. Excision permits definitive diagnosis, the stump being allowed to retract beneath the belly of the sternomastoid muscle. However, excision is not always indicated, and the diagnosis can be made clinically allowing for a more conservative treatment policy.


Asunto(s)
Neuroma/etiología , Glándula Parótida/cirugía , Complicaciones Posoperatorias/etiología , Humanos , Neuroma/diagnóstico , Neuroma/cirugía , Complicaciones Posoperatorias/diagnóstico , Complicaciones Posoperatorias/cirugía , Estudios Retrospectivos
6.
J Laser Appl ; 10(4): 174-80, 1998 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-10182367

RESUMEN

The use of laser diode pointers that operate in the visible radiation region (400-760 nm) is becoming widespread. These pointers are intended for use by educators while presenting talks in the classroom or at conventions and meetings. They are also useful in any situation where one needs to point out special items during any instructive situation. The pointers can be purchased in novelty stores, mail-order magazines, office supply stores, common electronic stores, and over the internet. The power omitted by these laser pointers ranges from 1 to 5 mW. The potential for hazard with laser pointers is generally considered to be limited to the unprotected eyes of individuals who might be exposed by a direct beam (intrabeam viewing). No skin hazard usually exists. There are, however, even more powerful laser pointers now appearing. The units are imported into the U.S. often without proper manufacturer certification or labeling. The potential for hazards with these devices is not well understood by the general public and workers, and numerous exposure incidents have been recorded by the authors. Users of these products need to be alerted to the potential hazards and be encouraged to follow appropriate safety recommendations. These factors are discussed and safety recommendations for laser pointers are presented.


Asunto(s)
Seguridad de Productos para el Consumidor , Rayos Láser , Certificación , Tecnología Educacional/instrumentación , Electrónica/instrumentación , Exposición a Riesgos Ambientales , Diseño de Equipo , Seguridad de Equipos , Lesiones Oculares/etiología , Guías como Asunto , Humanos , Rayos Láser/efectos adversos , Rayos Láser/clasificación , Rayos Láser/normas , Exposición Profesional , Etiquetado de Productos , Retina/efectos de la radiación , Trastornos de la Visión/etiología
7.
Appl Radiat Isot ; 72: 89-95, 2013 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-23208237

RESUMEN

Transmission measurements of radiation through process pipes provide a non-intrusive method of determining the amount of product present in the pipes. The product could be a liquid, a slurry, or a gas, which is the most challenging because of the low density. Traditionally, these techniques have used a radioactive source that has to be replaced periodically. We have developed a transmission technique based on an X-ray tube instead of a decaying source. A notch filter is used to provide a narrow transmission line, and a thin silicon transmission detector is used to monitor the X-ray tube output. The transmitted X-rays are measured with a high-throughput gamma spectrometer that consists of a NaI(Tl) detector and an MCA with precise dead time correction. This spectrometer provides stable transmission measurements with an accuracy of a fraction of a percent. The shielding and collimator are made of machinable tungsten for thermal mechanical stability, as well low-cost, low-weight tungsten powder in polymer castings. We describe two methods of measuring the pipe wall thickness without evacuating the pipe. Our particular application was for enrichment monitors for UF(6) in process pipes. Enrichment monitors that are independent of the plant data require two measurements: a transmission measurement to determine the total amount of uranium in the pipe and a measurement of the 186-keV gamma-ray line to determine the amount of (235)U present. The ratio of these values gives the enrichment. Previous designs used a decaying radioactive source such as (57)Co (122 keV, T(½)=272 days) or (109)Cd (22 keV, T(½)=1.2 years). A major effort was required to access and periodically replace these sources in operating plants. In this report, we describe the use of an X-ray tube, which eliminated the source problem, and other innovations. Then we present data from an enrichment monitor that incorporates these innovations.

12.
Radiol Technol ; 42(1): 15-6, 1970 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-5428998
13.
Am Ind Hyg Assoc J ; 50(8): 419-27, 1989 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-2508455

RESUMEN

There has been an extensive growth within the last five years in the use of high-powered lasers in various metalworking processes. The two types of lasers used most frequently for laser welding/cutting processes are the Neodymium-yttrium-aluminum-garnet (Nd:YAG) and the carbon dioxide (CO2) systems. When such lasers are operated in an open beam configuration, they are designated as a Class IV laser system. Class IV lasers are high-powered lasers that may present an eye and skin hazard under most common exposure conditions, either directly or when the beam has been diffusely scattered. Significant control measures are required for unenclosed (open beam), Class IV laser systems since workers may be exposed to scattered or reflected beams during the operation, maintenance, and service of these lasers. In addition to ocular and/or skin exposure hazards, such lasers also may present a multitude of nonlaser beam occupational concerns. Radiant energy measurements are reported for both the scattered laser radiation and the plasma-related plume radiations released during typical high-powered CO2 laser-target interactions. In addition, the application of the nominal hazard zone (NHZ) and other control measures also are discussed with special emphasis on Class IV industrial CO2 laser systems.


Asunto(s)
Rayos Láser/efectos adversos , Traumatismos por Radiación/etiología , Soldadura , Dióxido de Carbono , Ojo/efectos de la radiación , Dispositivos de Protección de los Ojos , Humanos , Dosis de Radiación , Traumatismos por Radiación/prevención & control , Piel/efectos de la radiación
14.
Lasers Surg Med ; 9(1): 45-9, 1989.
Artículo en Inglés | MEDLINE | ID: mdl-2927229

RESUMEN

Detailed radiometric analyses are reported on selected frosted-style laser surgical probes that are in use in laser surgical procedures. These measurements were performed in order to determine their nominal hazard zone (NHZ) and the requirement for protective eyewear. All measurements were conducted under worst-case conditions using a 30-W Nd:YAG laser. The results show that for the style of probe tested, the NHZ can be considered a spherical volume of 1.3 m and will require eye protection devices having a maximum optical density rating of 4.3 at 1.06 microns for all personnel who may come within that range.


Asunto(s)
Dispositivos de Protección de los Ojos , Terapia por Láser/instrumentación , Rayos Láser/efectos adversos , Equipos de Seguridad , Tecnología de Fibra Óptica/instrumentación , Humanos , Concentración Máxima Admisible
15.
Am Ind Hyg Assoc J ; 44(8): 572-9, 1983 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-6688700

RESUMEN

High power laser devices are being used for numerous metalworking processes such as welding, cutting and heat treating. Such laser devices are totally enclosed either by the manufacturer or the end-user. When this is done, the total laser system is usually certified by the manufacturer following the federal requirements of the Code of Federal Regulations (CFR) 1040.10 and 10.40.11 as a Class I laser system. Similarly, the end-user may also reclassify an enclosed high-power laser into the Class I category following the requirements of the American National Standards Institute (ANSI) Z-136.1 (1980) standard. There are, however, numerous industrial laser applications where Class IV systems are required to be used in an unenclosed manner. In such applications, there is concern for both ocular and skin hazards caused by direct and scattered laser radiation, as well as potential hazards caused by the optical radiation created by the laser beam's interaction with the metal (i.e. the plume radiation). Radiant energy measurements are reported for both the scattered laser radiation and the resultant plume radiations which were produced during typical unenclosed Class IV Neodymium-YAG laser welding processes. Evaluation of the plume radiation was done with both radiometric and spectroradiometric measurement equipment. The data obtained were compared to applicable safety standards.


Asunto(s)
Rayos Láser/efectos adversos , Medicina del Trabajo , Soldadura , Accidentes de Trabajo/prevención & control , Dispositivos de Protección de los Ojos , Humanos , Riesgo , Seguridad , Piel/lesiones
16.
J Occup Med ; 36(2): 133-6, 1994 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-8176510

RESUMEN

Two cases of Waldenstrom's macroglobulinemia (WM) that occurred in employees from one university academic department were investigated using approaches for both cluster and single case investigation. Common personal characteristics and potential past hazardous exposures were evaluated. The patients shared a young age at diagnosis, worked in the same building, and had similar duration of time between first entering the building and diagnosis of WM. No evidence was found to support the original hypothesis that exposure to radioactive material could be related to the occurrence of WM. Although this investigation did not identify a common causal agent among two cases of a rare disease, investigations of disease clusters may be useful for developing etiologic hypotheses even when a full-scale epidemiologic study is not undertaken. Detailed descriptions of case characteristics can help generate ideas for further research.


Asunto(s)
Enfermedades Profesionales/etiología , Exposición Profesional/efectos adversos , Macroglobulinemia de Waldenström/etiología , Adulto , Humanos , Masculino , Persona de Mediana Edad , Factores de Riesgo
18.
Am J Hosp Pharm ; 47(5): 1067-74, 1990 May.
Artículo en Inglés | MEDLINE | ID: mdl-2337096

RESUMEN

A portable system that uses fluorescence stimulated by visible light to identify doxorubicin contamination on skin and surfaces was studied. When activated by violet-blue light in the 465-nm range, doxorubicin fluoresces, emitting orange-red light in the 580-nm range. The light source to stimulate fluorescence was a slide projector with a filter to selectively pass short-wave (blue) visible light. Fluorescence was both observed visually with viewing spectacles and photographed. Solutions of doxorubicin in sterile 0.9% sodium chloride injection were prepared in nine standard concentrations ranging from 2 to 0.001 mg/mL. Droplets of each admixture were placed on stainless steel, laboratory coat cloth, pieces of latex examination glove, bench-top absorbent padding, and other materials on which antineoplastics might spill or leak. These materials then were stored for up to eight weeks and photographed weekly. The relative ability of water, household bleach, hydrogen peroxide solution, and soap solution to deactivate doxorubicin was also measured. Finally, this system was used to inspect the antineoplastic-drug preparation and administration areas of three outpatient cancer clinics for doxorubicin contamination. Doxorubicin fluorescence was easily detectable with viewing spectacles when a slide projector was used as the light source. The photographic method was sensitive for doxorubicin concentrations from 2.0 to 0.001 mg/mL. Immersion of study materials in bleach for one minute eliminated detectable fluorescence. Doxorubicin contamination is detectable for at least eight weeks in the ambient environment. Probable doxorubicin contamination was detected in two of the three clinics surveyed. A safe, portable system that uses fluorescence stimulated by visible light is a sensitive method for detecting doxorubicin on skin and surfaces.


Asunto(s)
Doxorrubicina/análisis , Piel/análisis , Doxorrubicina/efectos de la radiación , Fluorescencia , Humanos , Luz , Fotometría , Rayos Ultravioleta
19.
Lasers Surg Med ; 9(3): 276-81, 1989.
Artículo en Inglés | MEDLINE | ID: mdl-2733536

RESUMEN

A preliminary study was conducted to determine the effectiveness of a smoke evacuation system used in laser surgery. A 30 W medical CO2 continuous wave (CW) laser was used to make cuts in a pork chop to simulate smoke production during laser surgery. A commercially available smoke evacuation system was used to control the smoke from the simulated surgery. The smoke concentration was measured at 6 in and at 3 and 4 ft from site of laser interaction. The nozzle of the smoke evacuator was located at distances of 2, 6, and 12 in from the surgical site to measure the relative effectiveness of the control. Complete control of smoke was achieved when the nozzle was located at 2 in, but significant amounts of smoke escaped when the nozzle was located at 6 and 12 in. Suggestions for the use of the smoke evacuation system and areas for further study are given.


Asunto(s)
Terapia por Láser , Humo/prevención & control , Ventilación , Diseño de Equipo , Estudios de Evaluación como Asunto , Humo/análisis
20.
Appl Opt ; 20(14): 2352-66, 1981 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-20332961

RESUMEN

The purposes and functions of semitransparent eye protective curtains are analyzed. Based upon this analysis, functional requirements are developed, and design requirements are specified for optimum curtains to be used with open arc welding and arc cutting processes. Such curtains also protect against other high intensity broad-spectral-band sources such as compact arc lamps. The requirements for filtering our hazardous UV radiation and blue light must be balanced against the need for transparency in the visible spectrum and the need for reduced glare. Infrared attenuation is shown to be of very little importance.

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