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排序方式: 共有337条查询结果,搜索用时 31 毫秒
21.
The role of acid in the pathogenesis of indomethacin-induced gastric antral ulcers in the rat. 总被引:1,自引:1,他引:0
Clayton NM Oakley I Williams LV Trevethick MA 《Alimentary pharmacology & therapeutics》1996,10(3):339-345
BACKGROUND: The role of acid in the pathogenesis of indomethacin- induced ulcers of the rat gastric antrum was studied by comparing the effects of pretreating animals with both long-acting (loxtidine, AH22216) and short-acting (ranitidine and cimetidine) inhibitors of acid secretion. RESULTS: Ranitidine and cimetidine were much weaker at inhibiting antral damage when compared to their reported potencies as antisecretory agents. In marked contrast, loxtidine and AH22216 inhibited indomethacin-induced antral ulcers at doses similar to their reported potencies as inhibitors of acid secretion. Histological analysis at doses causing near maximal inhibition of macroscopic damage revealed an almost complete absence of ulcers but a large and significant increase in mucosal damage due to superficial erosions. Hourly dosing with hydrochloric acid reversed the protective effect of ranitidine, cimetidine and loxtidine on macroscopic damage and, histologically, this was associated with the widespread appearance of antral ulcers and a reduction in the proportion of mucosal damage caused by superficial erosions. CONCLUSIONS: The results of this study suggest that the pathogenesis of nonsteroidal anti-inflammatory drug (NSAID)-induced antral ulcers involves at least two stages: (1) an initial acid-independent formation of mucosal erosions followed by (2) an acid-dependent conversion of erosions to frank ulcers. Clinically, drugs that suppress acid completely for long periods may be very effective in preventing NSAID-induced gastric antral ulcers. 相似文献
22.
Wells K Vaughan J Pajewski TN Hom S Ngamtrakulpanit L Smith A Nguyen A Turner R Hunt J 《Thorax》2005,60(1):27-31
BACKGROUND: Measurement of pH in exhaled breath condensate (EBC) is robust and simple. Acidic source fluid (airway lining fluid) traps bases while volatilising acids, leading to EBC acidification in many lung diseases. Lower airway ammonia is one determinant of airway lining fluid pH, raising the concern that addition of the base ammonia by contamination from the mouth might confound EBC pH assays. METHODS: Three discrete methods were used to limit oral ammonia contamination of EBC collections: endotracheal intubation, oral rinsing, and -40 degrees C condenser temperatures. Separately, ammonia was removed from collected EBC samples by lyophilisation and resuspension. Intraweek and intraday variability of ammonia concentration was determined in 76 subjects, and ammonia and pH from a further 235 samples were graphically compared. Ammonia was assayed spectrophotometrically and pH was assessed after deaeration. RESULTS: Data from 1091 samples are presented. Ammonia was reduced in EBC by all methods. Endotracheal intubation decreased EBC ammonia from a mean (SD) of 619 (124) microM to 80 (24) microM (p<0.001, n=32). Oral rinsing before collection also led to a decline in EBC ammonia from 573 (307) microM to 224 (80) microM (p=0.016, n=7). The colder the condensation temperature used, the less ammonia was trapped in the EBC. Lyophilisation removed 99.4 (1.9)% of ammonia. Most importantly, the pH of EBC never decreased after removal of ammonia by any of these methods. Intraweek and intraday coefficients of variation for ammonia were 64 (27)% and 60 (32)%, which is substantially more variable than EBC pH assays. CONCLUSIONS: Although ammonia and pH appear to correlate in EBC, the oral ammonia concentration is not an important determinant of EBC pH. No precautions need to be taken to exclude oral ammonia when EBC pH is of interest. The low pH and low ammonia found in EBC from patients with lung diseases appear to be independent effects of volatile compounds arising from the airway. 相似文献
23.
NM?JomhaEmail author PC?Anoop Janet?AW?Elliott K?Bagnall LE?McGann 《BMC musculoskeletal disorders》2003,4(1):5
Background
The identification of live cells using membrane integrity dyes has become a frequently used technique, especially with articular cartilage and chondrocytes in situ where tissue slices are used to assess cell recovery as a function of location. The development of a reproducible computerised method of cell evaluation would eliminate many variables associated with manual counting and significantly reduce the amount of time required to evaluate experimental results.Methods
To validate a custom computerised counting program, intra-person and inter-person cell counts of nine human evaluators (three groups – unskilled, novice, and experienced) were compared with repeated pixel counts of the custom program on 15 digitised images (in triplicate) of chondrocytes in situ stained with fluorescent dyes.Results
Results indicated increased reproducibility with increased experience within evaluators [Intraclass Correlation Coefficient (ICC) range = 0.67 (unskilled) to 0.99 (experienced)] and between evaluators [ICC = 0.47 (unskilled), 0.85 (novice), 0.93 (experienced)]. The computer program had perfect reproducibility (ICC = 1.0). There was a significant relationship between the average of the experienced evaluators results and the custom program results (ICC = 0.77).Conclusions
This study demonstrated that increased experience in cell counting resulted in increased reproducibility both within and between human evaluators but confirmed that the computer program was the most reproducible. There was a good correlation between the intact cell recovery determined by the computer program and the experienced human evaluators. The results of this study showed that the computer counting program was a reproducible tool to evaluate intact cell recovery after use of membrane integrity dyes on chondrocytes in situ. This and the significant decrease in the time used to count the cells by the computer program advocate its use in future studies because it has significant advantages.24.
25.
Segal I; Sharer NM; Kay PM; Gutteridge JM; Braganza JM 《QJM : monthly journal of the Association of Physicians》1996,89(1):45-53
Vitamin C can be used to overcome oxidative stress and ease pain in chronic
pancreatitis. But its use is deprecated in conditions of tissue iron
overload, because its bioactive form, ascorbate, can accelerate
free-radical reactions that are driven by transition metals. We measured
iron, ascorbate and copper in Sowetan Blacks (RSA) with chronic
pancreatitis, obtaining serum/plasma from 14 consecutive patients and 15
controls. Compared with data from corresponding groups in Manchester,
African samples had less ascorbate (p < 0.0001), but more caeruloplasmin
(p < 0.0001). African and British controls had comparable iron and
iron-binding capacity. Plasma from African patients had less ascorbate than
that from African controls (p < 0.005) and in six samples, ferritin
exceeded 300 micrograms/l (677 pmol/l). Low- molecular-mass iron or copper,
capable of participating in free radical reactions, was not detected.
British patients, had similar caeruloplasmin levels to African patients but
higher ascorbate levels. There is no evidence of iron overload in our
African samples. Outwardly healthy controls from Soweto have elevated
levels of caeruloplasmin, possibly to compensate for dietary deficiency of
ascorbate. Persistent oxidative stress is a unifying feature of chronic
pancreatitis, but its degree is higher in African than British patients.
Supplements of vitamin C should be safe in Blacks of southern Africa.
相似文献
26.
To determine the cause of a positive direct antiglobulin test (DAT), blood banks routinely perform serologic tests on eluates prepared from DAT-positive red cells. Negative eluates traditionally have been suspected to be associated with drug reactions. This report confirms that the most frequent cause of a positive DAT and a nonreactive eluate is hypergammaglobulinemia. The results of 74 patient samples with positive DATs were analyzed retrospectively. Eluates prepared from the red cells of 54 patients (72.9%) reacted; eluates from 20 patients (27.1%) did not react. This latter group had identical serologic and clinical findings, suggesting that they made up a homogeneous group. In particular, the patients had a positive DAT, a negative indirect antiglobulin test, and a negative eluate; an increased serum concentration of IgG; and no evidence of hemolysis. In a subsequent study, DATs were performed prospectively on red cells from 44 consecutive patients with elevated serum IgG levels. The serum IgG concentration was highest in the three patients whose red cells had a positive DAT. The DAT also became positive in two patients treated with high-dose intravenous gammaglobulin (IV IgG). These studies indicate that a negative eluate from red cells with a positive DAT, a common serologic finding, is often caused by hypergammaglobulinemia. The authors postulate that IgG binds nonspecifically to the red cells because of the hypergammaglobulinemia. 相似文献
27.
QUADAS评价:一种用于诊断性研究的质量评价工具(修订版) 总被引:2,自引:0,他引:2
背景 QUADAS是一种新近发展起来的诊断性研究的质量评价工具。虽然已有系统评价采用了QUADAS,但尚未得以正式确证。本研究的目的是评价QUADAS的有效性和实用性。方法3位评价者采用QUADAS独立评价30项研究的质量。比较每位评价者的评分与最终结论之间的意见一致度。这主要是通过比较所有QUADAS条目的总分和每个单项的得分来实现的。20位曾在其系统评价中使用过QUADAS的评价者就其使用经验完成一份简短的问卷。结果就所有条目而言,每位评价者的评分与最终结论之间的意见一致度分别达到了91%、90%和85%。就单项QUADAS条目而言,一致度在50%至100%之间,中位值是90%。与难以解释的试验结果和退出病例相关的条目,评分结果差异最大。有关QUADAS内容的反馈意见普遍较好,仅少数评价者提出了有关QUADAS涵盖面、使用便利性、评分说明的清晰度及有效性方面的问题。结论QUADAS内容本身无需作大的修改。评价过程的主要困难出现在难以解释的试验结果和退出病例这2个条目的评分上。对这些条目的评分指南提出了修改意见。评价者必需根据其系统评价制定相应的评分指南,并确保所有评价者都清楚如何评分。评价者还应考虑是否所有的QUADAS条目都与其系统评价相关,以及其他质量条目是否应作为其系统评价的评价部分。 相似文献
28.
Winning the battle but losing the war: methicillin-resistant Staphylococcus aureus (MRSA) infection at a teaching hospital 总被引:2,自引:0,他引:2
Farrington M; Redpath C; Trundle C; Coomber S; Brown NM 《QJM : monthly journal of the Association of Physicians》1998,91(8):539-548
A methicillin-resistant Staphylococcus aureus (MRSA) control policy, aimed
at eradication, was established at a 1000-bed hospital in 1985, applied
consistently for 10.5 years, and then relaxed. Its components included
screening of high-risk patients, transfer of carriers to exhaust-ventilated
isolation rooms, closure of wards to new admissions when local transmission
was detected, MRSA screening during outbreaks, and prospective collection
of clinical and epidemiological information. During the eradication policy
period, every 6 months, a mean of 5.1 patients (range 1-12) already
carrying MRSA were admitted, and a mean of 3.6 (range 0-16) acquired
carriage in the hospital. The largest outbreak comprised 11 patients
despite epidemic MRSA strain EMRSA-16 being introduced six times, and MRSA
did not become endemic. MRSA- positive admissions increased progressively
from 1993; nursing staff workload increased, areas available for
alternative patient accommodation were reduced, the resulting ward closures
interfered with clinical services, and hence the control policy was relaxed
in mid- 1995. Isolation facilities were overwhelmed with 622 new patient-
isolates in the next 18 months, and there were 67 clinical infections in
1996. The proportion of blood cultures positive for MRSA rose nearly
sevenfold by 1996 and 27-fold by 1997. Thus, repeated eradication of MRSA,
even epidemic strains, by use of a stringent policy, is possible given
sufficient resources, whereas flexible national guidelines designed to
control, but not eradicate, epidemic staphylococci, are currently unlikely
to be successful. The costs of eradication policies need to be weighed
against those of endemicity.
相似文献
29.
JM Ranson NM Pantelides D Gharpuray Pandit JKG Laitung 《Journal of plastic, reconstructive & aesthetic surgery》2018,71(9):1269-1273
Objectives
The ‘10% rule’ has become widely accepted by surgeons performing sentinel lymph node biopsy (SLNB) for melanoma. The purpose of this study was to compare the ‘10% rule’ with alternative node harvesting criteria. In particular, we were interested to see whether the use of blue dye had any impact on the sensitivity of the test and whether it is necessary to remove all hot nodes.Methods
We reviewed 537 SLNBs performed for primary melanoma from 2009–2015. SLNB was offered to all patients with 1–4?mm Breslow thickness melanoma and sentinel nodes were harvested according to the ‘10% rule’.Results
One hundred sixteen patients (22%) had at least one positive sentinel node and there were 45 positive nodal basins from which more than one sentinel node had been harvested. Excluding blue dye and sampling only hot nodes would have enabled a 5% reduction in nodes harvested, without any compromise in the sensitivity of the test. However, applying harvesting criteria whereby not all hot nodes are taken was associated with a loss of sensitivity, with positive sentinel nodes being missed and patients understaged.Conclusions
Our data do not support the continued use of blue dye in SLNB for melanoma, as it does not improve the sensitivity of the test. This series adds to growing evidence, suggesting that the ‘10% rule’ with the inclusion of blue nodes should be reconsidered and that radiocolloid tracer alone is sufficient for sentinel node localisation. 相似文献30.
Koukouritaki SB Poch MT Henderson MC Siddens LK Krueger SK VanDyke JE Williams DE Pajewski NM Wang T Hines RN 《The Journal of pharmacology and experimental therapeutics》2007,320(1):266-273
Flavin-containing monooxygenases (FMOs) are important for the disposition of many therapeutics, environmental toxicants, and nutrients. FMO3, the major adult hepatic FMO enzyme, exhibits significant interindividual variation. Eighteen FMO3 single-nucleotide polymorphism (SNP) frequencies were determined in 202 Hispanics (Mexican descent), 201 African Americans, and 200 non-Latino whites. Using expressed recombinant enzyme with methimazole, trimethylamine, sulindac, and ethylenethiourea, the novel structural variants FMO3 E24D and K416N were shown to cause modest changes in catalytic efficiency, whereas a third novel variant, FMO3 N61K, was essentially devoid of activity. The latter variant was present at an allelic frequency of 5.2% in non-Latino whites and 3.5% in African Americans, but it was absent in Hispanics. Inferring haplotypes using PHASE, version 2.1, the greatest haplotype diversity was observed in African Americans followed by non-Latino whites and Hispanics. Haplotype 2A and 2B, consisting of a hypermorphic promoter SNP cluster (-2650C>G, -2543T>A, and -2177G>C) in linkage with synonymous structural variants was inferred at a frequency of 27% in the Hispanic population, but only 5% in non-Latino whites and African Americans. This same promoter SNP cluster in linkage with one or more hypomorphic structural variant also was inferred in multiple haplotypes at a total frequency of 5.6% in the African-American study group but less than 1% in the other two groups. The sum frequencies of the hypomorphic haplotypes H3 [15,167G>A (E158K)], H5B [-2650C>G, 15,167G>A (E158K), 21,375C>T (N285N), 21,443A>G (E308G)], and H6 [15,167G>A (E158K), 21,375C>T (N285N)] was 28% in Hispanics, 23% in non-Latino whites, and 24% in African Americans. 相似文献