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81.
IgM allotype heterozygous F1 mice were independently suppressed for Igh6a or Igh6b to
evaluate the contribution of B-1 and B-2 cells to natural serum IgM levels and Ab responses.
B-2 B cells expressing IgM of the suppressed allotype were evident in the spleens of
suppressed mice 4 to 6 weeks after cessation of the suppression regimen, whereas B-1 B
cells of the suppressed allotype were undetectable for up to 9 months. Although serum IgM
of the suppressed allotype was initially depleted in mice suppressed for either allotype, by
7 months of age, there were detectable levels of IgM of the suppressed allotype in the
serum; however, the levels were significantly below that found in nonsuppressed mice.
When mice were immunized with either the T-independent or T-dependent form of
phosphorylcholine, those suppressed for either allotype, and consequently depleted of B-1
B cells of that allotype, did not respond with phosphorylcholine-specific IgM of the
suppressed allotype. In contrast, when mice were immunized with α1-3 dextran, the Igh6a
allotype-suppressed mice were able to produce dextran-specific IgM of that allotype. These
results show that allotype-bearing B-1 cells of both allotypes can be effectively suppressed
by this suppression protocol and this produces long-lasting effects on B-1 cell levels and
serum IgM of the suppressed allotype. These observations reflect the derivation of the
majority of B-1 cells from fetal-neonatal precursors, which cannot be replaced by newly
emerging B-2 cells of adult origin. Their ablation by antibody treatment results in
permanent alterations to the adult B-cell repertoire. 相似文献
82.
Background. A single deep inspiration (DI) is known to be a potent bronchodilator but it is not known if repeated DI can accelerate sustained recovery from bronchoconstriction. Methods. We induced sustained bronchoconstriction using increasing concentrations of nebulized methacholine (Mch) during tidal breathing and assessed airway narrowing by measuring respiratory resistance (Rrs) using forced oscillation in six healthy subjects. On separate days we examined the effects of DI every 3 minutes and of prohibition of DI on recovery of Rrs for 30 minutes after the end of Mch nebulization. Results. Bronchoconstriction (Rrs ∼ 150% above baseline) was induced. DI during recovery had a transient bronchodilator effect but no cumulative effect. At 30 minutes after end of nebulization (and 2 minutes after the last DI) Rrs was 87% above baseline compared to 93% above baseline when DI was prohibited. Conclusion. Recovery from induced bronchoconstriction with methacholine was slow (∼ 2%/min) and not accelerated by frequent DI. 相似文献
83.
84.
85.
Ann Lecluyse 《The European journal of health economics》2007,8(3):237-243
This paper provides new evidence on the degree of income-related inequality in self-assessed health in Belgium. First of all,
we combine the time dimension, which has been shown to be very important in the analysis of inequality, and the use of the
recently developed interval regression approach to transform a categorical health variable in a continuous one. Second, we
measure how the long-run inequality differs from the short-run inequality. Finally, we decompose this health-related income
mobility index as well as the long-run concentration index (CI) itself into its contributors. Using data from the panel survey
of Belgian households (1994–2002), we find that health is pro-rich distributed and that its inequality is underestimated by
9.45% when neglecting the dynamics of individuals over time. Income, education, job status and age are the most important
contributors in the CI and the difference between the short-run and long-run inequality.
相似文献
86.
87.
88.
89.
Ann Goetting 《The journal of primary prevention》1994,14(3):169-186
This paper examines delinquency as it relates to family influences. 相似文献
90.
Abstract A previous study of the sensitivity and accuracy of a standardized radiographic technique for the disclosure of root cavities in a cadaver material indicated that it was not possible to perceive small artificial “resorption” cavities. Using the same material, the aim of the present study was to evaluate whether the use of subtraction radiography would improve the detection of root cavities. In an autopsy material of five mandibular blocks each containing two premolars, small, medium, and large cavities were drilled in the cervical, middle, and apical thirds of the proximal and oral root surfaces. Each jaw block was radiographed before (B) and after (A) cavity preparation with three different exposure times resulting in light, medium, and dark film densities. The radiographs were digitized. Digital subtraction was performed between the A- and B images of varying densities by a computer program developed for dental subtraction radiography. Conventional and reverse contrast modes of the subtraction image were assessed independently by four observers. The results showed small inter- and intraobserver differences in diagnostic accuracy for assessment of total number of root cavities. Original film density did not influence the diagnostic performance in the resulting subtraction image. Contrast mode in the subtraction image influenced diagnostic performance as the majority of observers did best with the reverse contrast mode (p<0.05). Some of the small root cavities were disclosed by the subtraction technique, but overall accuracy was not increased compared to conventional radiography. 相似文献