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1.
2.
Six-Month Exposure of Strain A/J Mice to Cigarette Sidestream Smoke: Cell Kinetics and Lung Tumor Data 总被引:3,自引:1,他引:2
Male strain A/J mice were exposed to sidestream smoke (SS) generatedfrom burning Kentucky 1R4F reference cigarettes. Chamber concentrationswere 4 mg/m3 of total suspended respirable particulate matter(TSP). Animals were exposed 6 hr a day, 5 days a week. One-weekcumulative labeling indices were significantly increased inthe large intrapulmonary airways during the 1st week and inthe respiratory epithelium of the nasal and maxillar turbinatesduring the first 3 weeks of exposure and then returned to controlvalues. Subsequently, signs of increased cell proliferationwere again found in the nasal and maxillar turbinates duringthe 9th and 16th exposure weeks. The experiment was terminatedafter 6 months. The number of animals bearing lung tumors wasthe same in smoke-exposed as in filtered airexposed animalsas was the average number of tumors per lung. Analysis of theDNA of individual tumors obtained from exposed and control micefor K-ras mutations suggested that exon 2 might be a specifictarget for SS. It was concluded that (1) duration of exposurewas too short or (2) concentration of TSP was too low to reveala possible carcinogenic potential of SS in strain A/J mice orthat (3) SS is not carcinogenic in strain A mice. 相似文献
3.
Stochastic models for geriatric in-patient behaviour 总被引:1,自引:0,他引:1
Departments of geriatric medicine engage in two distinct formsof clinical activity: acute/rehabilitative and long-stay care.These are organizationally distinct and have very differentresource needs. Current hospital planning models, however, assumethat patients all move through the system at the same rate,thereby ignoring this effect of inherent heterogeneity in patientbehaviour. The present paper describes the movement of patientsthrough geriatric hospitals by a two-stage continuous-time Markovmodel, where the stages represent acute/rehabilitative and long-staypatients respectively. Patients are initially admitted to thefirst stage, from which they may depart from the system, bydeath or discharge, or move into the second stage, from whichthey eventually depart by death or discharge (unlikely). Admissionsare modelled in two ways: either as replacements for departuresor as a Poisson stream. Expressions for the distribution andmovement of numbers of patients are derived and evaluated fordata from a number of hospitals. Such an approach has the advantage,over previous crude models, of taking into account differenttypes of patients and introducing variability, thus making itpossible to extract variances as well as means of numbers ofgeriatric patients requiring hospital care. 相似文献
4.
EDWARD VICTOR ROSS MD NATHAN S. UEBELHOER DO YACOV DOMANKEVITZ PHD 《Dermatologic surgery》2007,33(12):1466-1469
BACKGROUND Purpura-free elimination of telangiectases with a single pass of a pulsed dye laser with a large spot has proved difficult.
OBJECTIVE The purpose of this report was to define parameters that achieve single-pass purpura-free telangiectasia reduction.
MATERIALS Thirty patients between the ages of 23 and 78 years were treated with a pulsed dye laser with a 10-mm spot and fluences ranging from 9 to 10 J/cm2 . The macropulse width was 20 ms. Each macropulse was composed of eight pulselets. Treatments were carried out over facial areas with discrete telangiectases.
RESULTS Smaller telangiectases (<600 μm) showed transient bluing followed by stenosis. Larger vessels (600–10,000 μm) showed bluing but inconsistent closure. A second pass typically resulted in closure.
CONCLUSION A modified pulsed dye laser was capable of single-pass purpura-free reduction with a 10-mm spot size. 相似文献
OBJECTIVE The purpose of this report was to define parameters that achieve single-pass purpura-free telangiectasia reduction.
MATERIALS Thirty patients between the ages of 23 and 78 years were treated with a pulsed dye laser with a 10-mm spot and fluences ranging from 9 to 10 J/cm
RESULTS Smaller telangiectases (<600 μm) showed transient bluing followed by stenosis. Larger vessels (600–10,000 μm) showed bluing but inconsistent closure. A second pass typically resulted in closure.
CONCLUSION A modified pulsed dye laser was capable of single-pass purpura-free reduction with a 10-mm spot size. 相似文献
5.
NOEL S. STURM ANN MARIE HUTZLER CLINTON S. DAVID BASSEM Y. AZIZEH DEV TRIVEDI VICTOR J. HRUBY 《Chemical biology & drug design》1997,49(4):293-299
We have designed and synthesized eight compounds 2-9 which incorporate neutral, hydrophobic amino acid residues in positions 9, 11 and 16 of the glucagon molecule: (2) [desHis1,Va19,11e11,16] glucagon amide, (3) [desHis1,Val9,11,16]glucagon amide, (4) [desHis1,Va19,Leu11,16]glucagon amide, (5) [desHis1,Nle9,11e11,16]glucagon amide, (6) [desHis1,Nle9,Val11,16]glucagon amide, (7) [desHis1,Nle9,Leu11,16]glucagon amide, (8) [desHis1,Val9,Leu11,16,Lys17,18,Glu21]glucagon amide and (9) [desHis1,Nle9,Leu11,16,Lys17,18,Glu21]glucagon amide. The effect of neutral, hydrophobic residues at positions 9, 11 and 16 led to good binding to the glucagon receptor. Compared to glucagon (IC50= 1.5 nM), analogues 2-9 were found to have IC50 values of 6.0, 6.0, 11.0, 9.0, 2.5, 2.8, 6.5 and 7.0 nM, respectively. When these compounds were tested for their ability to block adenylate cyclase (AC) activity, they were found to be antagonists having no stimulation of adenyl cyclase, with PA2, values of 6.15, 6.20, 6.30, 7.25, 6.10, 7.30, 6.25 and 7.25, respectively. © Munksgaard 1997. 相似文献
6.
BUCCI THOMAS J.; WUSTENBERG WILLIAM; PERMAN VICTOR; WEISS DOUGLAS J.; DACRE JACK C.; BAUMEL IRWIN P.; PARKER ROBERT M. 《Toxicological sciences》1994,22(2):220-230
Diisopropyl methylphosphonate (DIMP), produced during manufactureof the chemical agent GB (Sarin), is a groundwater contaminantat Rocky Mountain Arsenal, Colorado. DIMP was fed for 90 daysto dark brown "Ranch Wild" mink housed under controlled indoorconditions. One-year-old mink, 10 of each sex, were fed 0, 50,450, 2700, 5400, or 8000 ppm in standard ranch diet. ActualDIMP consumption was 0, 8, 73, 400, 827, and 1136 mg/kg bodywt/day, respectively. Two additional groups of 10 served as"pair-fed" controls. Body weight and food intake were recordedweekly. Complete blood count and 15 chemical analytes were measuredat Weeks 0, 3, 7, and 13. Necropsy and microscopic examinationwere performed on all mink. No clinical morbidity or deathsoccurred. Both sexes fed 8000 ppm ate approximately 20% lessand weighed approximately 20% less than the controls; 5400 ppmfemales had a 10% weight decrement. Plasma cholinesterase (ChE)decreased in the top three dose groups starting at Week 3. At13 weeks, decrements were approximately 50% but returned tonormal after 1 week without DIMP. Erythrocyte ChE was not reduced.Heinz bodies occurred in 1015% of RBCs in 50% of 8000ppm mink at 13 weeks, and 0.12.0% of RBCs in 25% at 2700ppm. There were mild decreases in RBC count, hematocrit, andhemoglobin, and increases in reticulocyte count, at the 5400and 8000 ppm doses. All recovered within 3 weeks after DIMPwas with drawn. The 8000 ppm group had marginal splenic hematopoiesis,histologically. No other treatment-related changes were noted.The 450 ppm dose was a clear no-effect level (approximately73 mg DIMP/kg body wt/day). Compared to reports of similar studiesof DIMP in rats and dogs, these mink displayed no unique speciessusceptibility. 相似文献
7.
8.
MARY A. FOULKES DENNIS O. DIXON VICTOR DeGRUTTOLA STEVEN SELF 《Statistics in medicine》1996,15(21):2269-2270
9.
Carbachol, a cholinergic agonist, and GABAA receptor antagonists injected into the pontine dorsomedial reticular formation can trigger rapid eye movement (REM) sleep-like state. Data suggest that GABAergic and cholinergic effects interact to produce this effect but the sites where this occurs have not been delineated. In urethane-anesthetized rats, in which carbachol effectively elicits REM sleep-like episodes (REMSLE), we tested the ability of 10 nL microinjections of carbachol (10 m m ) and bicuculline (0.5 or 2 m m ) to elicit REMSLE at 47 sites located within the dorsal pontine reticular formation at the levels -8.00 to -10.80 from bregma (B) (Paxinos and Watson, The Rat Brain in Stereotaxic Coordinates , Academic Press, San Diego, 1997). At rostral levels, most carbachol and some bicuculline injections elicited REMSLE with latencies that gradually decreased from 242 to 12 s for carbachol and from 908 to 38 s for bicuculline for more caudal injection sites. As the latencies decreased, the durations of bicuculline-elicited REMSLE increased from 104 s to over 38 min, and the effect was dose dependent, whereas the duration of carbachol-elicited REMSLE changed little (104–354 s). Plots of REMSLE latency versus the antero-posterior coordinates revealed that both drugs were maximally effective near B-8.80. At levels caudal to B-8.80, carbachol was effective at few sites, whereas bicuculline-elicited REMSLE to at least B-9.30 level. Thus, the bicuculline-sensitive sites extended further caudally than those for carbachol and antagonism of GABAA receptors both triggered REMSLE and controlled their duration, whereas carbachol effects on REMSLE duration were small or limited by its concurrent REMSLE-opposing actions. 相似文献