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31.
Summary: We have developed a novel experimental model of cancer immunity in the frog, Xenopus , which may provide a useful alternative to murine tumor models and a way to assess whether the control of tumor development is a fundamental function of the immune system of vertebrates. In Xenoptis , tumor immunity can be studied in two developmentally distinct immune systems. The larval immune system reflects characteristics of an ancestral system that appears to function without classical MHC class I antigen presentation and an efficient effector mechanism. The adult system appears more highly evolved in that it is remarkably similar to that of mammals and is able to generate a potent antitumor response. This amphibian model also provides a unique system with which to investigate a postulated role of heat shock proteins as components of an ancestral system of antigen presentation and/or immune surveillance that predates the antigen presentation pathway that exclusively involves MHC molecules. 相似文献
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I. Nicholas Crispe 《Clinical & developmental immunology》1995,4(4):257-261
The hypothesis that prothymocytes are distinct from and regulated independently of
multilineage hemopoietic progenitors was tested by enumeration of these two cell populations
in normal versus congenitally athymic (nude) mice. The absence of a thymus and of
peripheral T cells in nude mice had no effect on the frequency of either multilineage
progenitors (day 12 CFU-S) or prothymocytes (CFU-T), suggesting that there is no feedback
regulation of CFU-T frequency. Thymus seeding from the bone marrow is therefore likely
to be regulated by the availability of niches for prothymocyte maturation, rather than by
feedback control of prothymocyte production. 相似文献
35.
Robert C. Knowlton MD Nicholas D. Lawn FRACP James M. Mountz MD PhD Ojha Buddhiwardhan MD Suzanne Miller RN BSN Jorge G. Burneo MD Ruben I. Kuzniecky MD 《Journal of neuroimaging》2004,14(4):324-330
PURPOSE: To examine the application of statistical parametric mapping (SPM) to analyze ictal single-photon emission computed tomography (SPECT) scans in surgical candidates with extratemporal lobe epilepsy. METHODS: The authors selected patients who underwent successful ictal SPECT acquisition in the process of surgical treatment of intractable partial epilepsy. Thirteen patients were identified who met inclusion criteria for confident seizure localization from either intracranial electroencephalogram recordings or epilepsy surgery outcome. In these cases, ictal scans were registered to an in-house-developed normal SPECT atlas composed of 14 spatially normalized brains of normal subjects. SPM96 was used to test on a voxel-by-voxel basis for statistically significant increases in blood flow associated with each patient's ictal scan. The results were then mapped back onto the patient's magnetic resonance image (MRI) for final interpretation. Statistical parametric mapping (SPM) analysis of ictal SPECT scans was compared to both conventional visual interpretation and the analysis of subtraction ictal SPECT co-registered to MRI (SISCOM). RESULTS: Ten of 13 patient scans showed localizing focal ictal increases in regional cerebral blood flow, all of which were concordant with ultimate epilepsy localization. Of the 3 cases not localized with SPM, 1 was localized by conventional visual interpretation and another, not localized by visual interpretation, was correctly localized with SISCOM. Two cases not localized by SISCOM were localized by both visual and SPM analysis. CONCLUSIONS: This work provides supportive evidence for proof of principle that SPM can be used to provide objective, accurate analysis of ictal SPECT scans in patients with extratemporal lobe epilepsy. 相似文献
36.
Emma J. Birks MRCP Magdi H. Yacoub DSc FRS Ani Anyanwu FRCS Rosemary Radley Smith FRCP Nicholas R. Banner FRCP Asghar Khaghani FRCS 《The Journal of heart and lung transplantation》2004,23(12):3688-1344
BACKGROUND: Transplantation for patients with a high pulmonary vascular resistance (PVR) carries an increased risk of mortality and right heart failure following heart transplantation and continues to be a major problem. We evaluated the use of hearts from patients who underwent heart and lung transplantation for primary pulmonary hypertension (PPH) as part of a domino procedure because these hearts have hypertrophied right ventricles used to increased pulmonary pressures, but could have a compromised left ventricle or irreversible damage of the right ventricle. METHODS: We reviewed 12 patients with PVR >4 Wood units who underwent orthotopic heart transplantation between 1989 and 1998 using hearts from donors with PPH as part of a domino procedure. RESULTS: We studied 10 men and 2 women, mean age 42.9 years. Mean PVR was 5.3 (range, 4-9) Wood units. Mean ischemia time was 85.3 minutes, and mean donor age was 32 years. Actuarial survival was 75% at 1 year and 75% at 5 years. In the early post-operative period, 3 patients had temporary arrhythmias, 2 required permanent pacemaker implantation, 1 had atrial fibrillation, and 1 had ventricular tachycardia that required defibrillator implantation. At a mean follow-up of 7.8 years, 2 patients had developed asymptomatic transplant coronary disease (both at 8.5 years after transplantation), 1 moderate and 1 very mild; the rest had none. Mean left ventricular ejection fraction at latest follow-up was 70.1% (range, 63%-78%). Right ventricular function assessed clinically and by echocardiography was adequate in the short and long term. CONCLUSIONS: Our results suggest that heart and lung recipients with PPH can provide useful donor hearts to patients with increased PVR and that these hearts function well in the intermediate and long term. 相似文献
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Systemic administration of the phosphodiesterase inhibitor rolipram (0.05–10.0 mg/kg, IP) produced a rapid and dose-related
increase in the amplitude of the acoustic startle response in rats. The (−) isomer was more potent than the (+) isomer in
enhancing startle amplitude. Rolipram increased startle responses that were elicited by brief electrical stimulation of the
ventral cochlear nucleus or nucleus reticularis pontis caudalis, two brainstem relay nuclei of the startle neural circuit.
A low (5 μg) dose of rolipram produced an excitatory effect on startle following spinal (lumbar intrathecal) infusion but
not following supraspinal (lateral ventricle) infusion. Rolipram (0.5 mg/kg, IP) excitation of startle was not blocked by
drugs which differentially disrupt the release of monoamines (DSP4, reserpine + alpha-methylpara-tyrosine, reserpine + para-chloro-phenylalanine)
or by drugs which differentially block monoamine receptors (haloperidol, prazosin, idazoxan, cinanserin, or cyproheptadine).
The marked increase in startle seen following systemic rolipram injection is attributable, at least in part, on an action
in the lumbar spinal cord that directly or indirectly facilitates neural transmission along the reticulospinal component of
the startle reflex neural pathway. The startle reflex should be a useful behavioral test system for studying the mechanism
of action of rolipram and related compounds purported to selectively inhibit calmodulin-independent forms of phosphodiesterase. 相似文献
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40.
The purposes of the study were: (1) to evaluate the effects of different surfaces on the relationship between subtalar and knee joint function, and (2) to examine/explore alternative approaches to the evaluation of these relationships. Five subjects ran under four different surface conditions of various hardness, while both rear and sagittal view kinematic data were collected (200 Hz). Critical parameters describing the knee angle and rearfoot motion were examined in conjunction with a curve analysis technique which incorporated slope differences and curve correlations. A repeated measure ANOVA design (surface × subject) was used along with single subject procedures. The results of the study support a strong inter-relationship between pronation and knee joint function via tibial rotation and underlined it as a possible mechanism for injury. Moreover, discrete point analysis might not be the most appropriate methodology for evaluating dynamic functions such as rearfoot motion and knee angle. Extreme methodological care must be exercised when evaluating these functions to avoid oversmoothing and/or masking correlations and differences due to differential subject responses and individual variability. The fact that increased impact force facilitated timing discrepancies between subtalar and knee joint function resulting in a transition of the pronation curve from a unimodal to bimodal configuration, is hypothesized as a possible explanation to better understand the inter-relationships among these lower extremity functions and their relationship to running injuries. 相似文献