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991.
Numerical simulation of aerosol particle transport by oscillating flow in respiratory airways 总被引:2,自引:0,他引:2
James K. Briant Duane D. Frank Anthony C. James L. Loren Eyler 《Annals of biomedical engineering》1992,20(6):573-581
Particle transport by oscillating flow in a tapered channel or in a tapered tube was computed from the complete equations
of motion. These geometries represent a simplified model of the divergent flow field of the mammalian bronchial tree. The
computed deformation profile of a line of particles, transported by the oscillatory motion, was compared with prior experimental
results and analytical calculations. All three methods agree that there is transport in the divergent direction of the tube
by an axial stream of steady drift in the core for moderately high frequency of oscillation (Womersley parameter in the range
of 1 to 10). Bidirectional flow is established by an annular stream in the convergent direction, with no net flow on integral
cycles of the oscillating fluid. At higher frequency, however, the steady stream transforms to a different shape in the tapered
tube, with transport in the divergent direction nearer the walls of the tube, rather than in the core. Transport by the continuing
streams with oscillatory ventilation of the respiratory tract should deliver medicinal aerosols of low intrinsic particle
mobility to the peripheral regions of the lungs. 相似文献
992.
James F Jones Elizabeth M Maloney Roumiana S Boneva Ann-Britt Jones William C Reeves 《BMC complementary and alternative medicine》2007,7(1):12
Background
Chronic fatiguing illnesses, including chronic fatigue syndrome (CFS), pose a diagnostic and therapeutic challenge. Previous clinical reports addressed the utilization of health care provided to patients with CFS by a variety of practitioners with other than allopathic training, but did not examine the spectrum of complementary and alternative medicine (CAM) therapies used. This study was designed to measure CAM therapy use by persons with fatiguing illnesses in the United States population. 相似文献993.
Mills JL Druschel CM Pangilinan F Pass K Cox C Seltzer RR Conley MR Brody LC 《American journal of medical genetics. Part A》2005,136(1):8-11
Women who take folic acid in the periconceptional period greatly reduce their chances of having a child with a neural tube defect (NTD). Using multivitamins may also reduce the risk of having a child with an omphalocele. In this study, we tested single nucleotide polymorphisms in folate-related enzyme genes for association with omphalocele. Polymorphisms in methylenetetrahydrofolate reductase (MTHFR), methylenetetrahydrofolate dehydrogenase (MTHFD1), the reduced folate carrier (SLC19A1), and transcobalamin II (TCN2) were examined in 25 children with euploid omphalocele and 59 matched controls. Omphalocele cases were significantly more likely to carry the T allele of MTHFR 677C-->T, a known risk factor for NTDs (odds ratio 3.50, 95% confidence interval 1.07-11.47, P=0.035). The MTHFD1 R653Q, SLC19A1 R27H, and TCN2 P259R polymorphisms showed no significant association with omphalocele. In this small study, the thermolabile variant of MTHFR, 677C-->T, was associated with an increased risk for omphalocele. This variant causes reduced enzyme activity, thus suggesting a mechanism by which multivitamins with folic acid might prevent omphalocele. Additional investigation is required. 相似文献
994.
Amy A. Eapen Kirsten M. Kloepfer Frederick E. Leickly James E. Slaven Girish Vitalpur 《Annals of allergy, asthma & immunology》2019,122(2):193-197
Background
Recent studies have suggested that removing foods from the diet to manage atopic dermatitis (AD), based on positive allergy test results, may lead to immediate allergic reactions on reintroduction of that food.Objective
To examine the frequency of oral food challenge (OFC) failures among foods removed from the diet as suspected AD triggers, focusing on the 5 major food allergens in the United States.Methods
OFCs to egg, milk, peanut, soy, and wheat, performed from 2008 to 2014, at a children's hospital's allergy clinics, were reviewed. OFCs were offered based on history and laboratory values. Reasons for food avoidance were classified as food allergy (IgE-mediated reaction occurring within 2 hours); sensitization only (lack of introduction because of positive test results); and removal because of test results during AD evaluation.Results
There were 442 OFCs performed, with 89 failures (20.1%). Reasons for OFCs included a history of food allergy (320 of 442 [72.4%]), food sensitization without any introduction (77 of 442 [17.4%]), and AD (45 of 442 [10.2%]). OFC failures among those who had food allergy (70 of 320 [21.9%]), sensitization only (13 of 77 [16.9%]), and suspected AD trigger (6 of 45 [13.3%]) did not significantly differ (P?=?.63). Wheat was more likely to be avoided than the other 4 foods for AD concerns (P < .001).Conclusion
The frequency of OFC failure among those who removed foods suspected as AD triggers was 13.3%, indicating a loss of tolerance. Restriction of foods to manage AD must be done with caution and close monitoring. 相似文献995.
Composite carcinoma-carcinoid tumors of the gastrointestinal tract. A morphologic, histochemical, and immunocytochemical study 总被引:1,自引:0,他引:1
R S Klappenbach R J Kurman C F Sinclair L P James 《American journal of clinical pathology》1985,84(2):137-143
A morphologic, histochemical, and immunocytochemical study of 20 cases of pure gastrointestinal carcinoids, adenocarcinomas, and mixed neoplasms composed of both elements, so-called composite carcinoma-carcinoid tumors (CCC), was undertaken in order to correlate the morphologic patterns with the immunocytochemical localization of carcinoembryonic antigen (CEA), serotonin, and a battery of polypeptide hormones (calcitonin, glucagon, insulin, gastrin, somatostatin, and adrenocorticotropin [ACTH]). Paraffin sections from five pure carcinoids, seven pure adenocarcinomas, and eight CCC from the stomach, small bowel, appendix, and colon were studied with mucicarmine, silver impregnation stains, and a peroxidase-anti-peroxidase technic. Of the eight CCC, all were mucin positive, four were argyrophilic, and three were argentaffin positive. CEA was present in all eight, serotonin in seven, and calcitonin in one. No other neurohormonal peptides were demonstrated. The distribution of serotonin and CEA generally corresponded to the morphologic pattern, but discordance was observed in two cases, i.e., serotonin was not always localized to areas of carcinoid and CEA not always confined to areas of carcinoma. All five pure carcinoids demonstrated intracytoplasmic localization of serotonin, whereas none contained intracytoplasmic CEA. In two cases, CEA was present within acinar lumens only. The seven colonic adenocarcinomas were argyrophil and argentaffin negative. All contained CEA within the cytoplasm and in gland lumens. None contained serotonin. None of the neurohormonal peptides was localized in either pure adenocarcinomas or carcinoids. This study reveals that among gastrointestinal neoplasms displaying morphologic patterns of adenocarcinoma and carcinoid, immunocytochemical localization of CEA and serotonin confirms their bidirectional differentiation and justifies the designation "composite carcinoma-carcinoid." 相似文献
996.
997.
Two mediated smoking cessation programs were subjected to a field evaluation. The Quit Kit is a printed self-help package, and "Calling It Quits" consists of five segments which were aired on the local television news. A sample of 239 persons requested the Quit Kit and were followed. At the 2-month and 12-month follow-ups, respectively, 13.6% and 17.9% of those surveyed reported abstinence. Results indicate the potential of mediated interventions. 相似文献
998.
Studies on the mechanism of phorbol ester-induced inhibition of intercellular junctional communication 总被引:1,自引:0,他引:1
Intercellular gap-junctional communication was measured using[14C]citrulline incorporation in co-cultures of argininosuccinatelyase-deficient human fibroblasts and argininosuccinate synthetase-deficientChinese Hamster V79 cells. As previously shown, in this systemjunctional communication is completely inhibited by the tumorpromoting phorbol ester 12-O-tetra-decanoylphorbol-13-acetate(TPA). In the absence of extracellular calcium, TPA inhibitionwas less pronounced. However, synergism with calcium ionophoreA23187 could not be demonstrated. Chlorpromazine, trifluoperazineand 3,4,5-trimethoxybenzoic acid 8-(diethylamino)octyl esterpartially antagonised the effect of TPA. No antagonism was demonstrablebetween calmidazolium and TPA. Treatment of co-cultures withexogenous phospholipase C or 1-oleoyl-2-acetylglycerol (OAG)resulted in communication inhibition, suggesting that proteinkinase C activation is involved in the mechanism of phorbolester-mediated communication inhibition. However co-cultureswhich had been made refractory to TPA by prolonged exposureto high concentrations remained sensitive to inhibition by phospholipaseC and OAG. These results suggest either that diacylglycerolcan produce other effects independent of protein kinase C activation,or that refractoriness to phorbol esters is not simply due toa decrease in the amount of protein kinase C. 相似文献
999.
Rats were trained to press a lever under a variable-interval (VI) schedule of water reinforcement. After stable responding had developed, a 4.5-KHz tone (CS) was conditioned classically to a 2.5-mA electric shock (US) in groups of animals which had been given various psychoactive drugs or saline. Twenty-four hours later, a stimulus generalization test was conducted in the absence of drug; during this session, tones that varied in frequency around 4.5 KHz were presented while the animals were responding under the VI schedule. In animals conditioned under saline, all tones (non-differentially) suppressed responding which, however, recovered gradually over time. This suppressive effect was eliminated by lysergic acid diethylamide (LSD; 0.2 and 0.32 mg/kg), cocaine (20 mg/kg), diazepam (2.5 mg/kg), lisuride (0.08 mg/kg), mescaline (20 mg/kg) and 5-methoxy-N,N-dimethyltryptamine (4 mg/kg), and was attenuated by amphetamine (4 mg/kg), pentobarbital (15 mg/kg) and morphine (4 mg/kg). Atropine (10 mg/kg), scopolamine (1 mg/kg), clonazepam (0.5 mg/kg), and chlorpromazine (4 mg/kg) did not alter the suppressive effect of the tone. The serotonin antagonist BC-105 (6 mg/kg) reversed the effect of 0.2 mg/kg of LSD. These results suggest (1) that drug-induced stimuli may overshadow other (e.g., external) stimuli during classical conditioning and, (2) that drugs might affect behavior by altering processes (stimulus control or others) that do not simultaneously involve response or motor control. 相似文献
1000.