同种异体组织工程复合皮肤移植修复大鼠皮肤缺损

目的：检测组织工程皮肤的生物活性及免疫原性，探讨临床可行性。方法：以新生SD大鼠皮肤为原材料培养组织工程复合皮肤并将其移植到成年Wistar大鼠，通过大体观察，组织学检测对不同时间自体，异体及组织工程复合皮肤移植进行比较，研究了组织工程复合皮肤的存活及免疫排斥情况。结果：异体皮肤移植组有明显的免疫排斥，组织工程皮肤组见有明显排斥，且与自体皮肤结合良好。结论：组织工程复合皮无明显的免疫排斥，是较好的皮肤移植替代品，具有潜在的发展前景。     

Middle latency auditory evoked potentials improve the detection of abnormalities along auditory pathways in multiple sclerosis patients.

Brain-stem and middle latency auditory evoked potentials (BAEPs and MLAEPs) have been studied in 34 multiple sclerosis (MS) patients. We were able to detect a central nervous system auditory pathway involvement in 17 (50%) of the patients: 38% by BAEPs alone (I-V inter-peak latency) and 47% by MLAEPs alone (Na and Pa peak latency). Five patients had abnormal MLAEPs with normal BAEPs whereas the opposite was detectable in only 1 patient. In addition, most MLAEP parameters in the MS group statistically differed from those obtained in the control group. Therefore, our results demonstrated that the auditory pathway impairment could frequently be located at a rostral level along the auditory radiation. In conclusion, even if only Na and Pa components were considered, MLAEPs succeeded in improving the sensitivity of the auditory evoked potential examination without increasing the false positive rate.     

Expression of the Ly-5 alloantigenic system on epidermal cells

The expression of Ly-5 alloantigens is confined to hemopoietic cell types and is therefore considered a valuable indicator for the bone marrow derivation of a given cell. The further finding that different hemopoietic cell lineages express different molecular forms of the Ly-5 alloantigens prompted us to investigate (1) whether murine epidermal cells or subpopulations thereof express Ly-5 specificities and if so, (2) whether the expression of particular molecular configurations of Ly-5 antigens would allow us to gain a clue about the derivation of certain epidermal cell populations. When epidermal sheets from BALB/c, C57Bl/6, and C3H/He mice, were exposed to monoclonal anti Ly-5.1 antibody in an indirect immunofluorescence technique, a system of evenly distributed, dendritic cells was visualized. Allelic exclusion of the Ly-5 system was demonstrated by replacing anti-Ly-5.1 antibody by anti-Ly-5.2 reagent and by using epidermal sheets from SJL/J mice. Studies on epidermal cell (EC) suspensions revealed that about 1.6-5.2% of C3H/He EC were Ly-5-reactive and that approximately equal numbers of Ly-5-positive cells bore either Thy-1 or Ia antigens. Electron microscopic studies disclosed two morphologically different Ly-5-positive cell populations, i.e., cells of the Langerhans cell lineage and a recently defined cell system, whose most prominent feature is the expression of the Thy-1 antigen. We have termed these cells dendritic Thy-1+EC (dTHY-1+EC). In order to define the molecular configurations of the Ly-5 alloantigens, EC and spleen cells were internally labeled and--after immunoprecipitation of cell-membrane detergent extracts with anti-Ly-5.1--were analyzed on sodium dodecyl sulfate-polyacrylamide gels. Spleen cells yielded 3 bands with a molecular weight of 180,000, 195,000, and 215,000, respectively, as is characteristic for T lymphocytes, non-T/non-B cells, and B lymphocytes. In contrast, a single 195,000-200,000 dalton band was found in precipitates of both untreated and Langerhans cell-depleted (anti-Ia+C) EC. These data demonstrate the existence and active biosynthesis of the Ly-5 alloantigenic system on certain EC populations, i.e., Langerhans cells and dThy-1+EC, and therefore imply that both cell types originate from a bone marrow-derived precursor. The expression of the same molecular configuration of Ly-5 alloantigens on both LC and dThy-1+EC suggest that these two cell populations do not belong either to the T-cell or to the B-cell lineage and imply an ontogenetic relationship between dThy-1+EC and Ia-positive EC.     

Neuromagnetic evidence of synchronized spontaneous activity in the brain following repetitive sensory stimulation

Neuromagnetic measurements in the visual and somatosensory modalities reveal that, following repetitive stimulation, the brain persists in emitting synchronized after-discharges in the form of oscillations with highly specific spectral composition. In the visual modality, this rhythmic activity is centered at the frequency of the resting alpha rhythm and it is most readily induced by stimulation of the same frequency. This suggests that the phenomenon is due to synchronization of the generators responsible for the natural rhythms by the steady-state stimulation and that these generators behave as resonant oscillators. The phenomenon could then be referred to as Synchronized Spontaneous Activity (SSA). The discovery of this phenomenon has important implications for modelling the dynamics of normal evoked and spontaneous cerebral activity as well as for the understanding of pathological conditions such as photically induced epilepsies.     

Inhaled nitric oxide in neonates and children with pulmonary hypertension

Fourteen critically ill neonatal and paediatric intensive care patients with various primary diagnoses and signs of associated pulmonary hypertension received inhaled nitric oxide (NO), 20–80 ppm, after failure of conventional therapy to improve oxygenation. NO administration was found to be associated with a significant improvement in postductal arterial oxygen tension (pre-NO: 3.75 (SD 1.39) kPa; post-NO: 6.05 (SD 1.70) kPa; p = 0.004). In 10 patients, NO was found to increase arterial oxygen tension with more than 1 kPa. In 2 of these patients, ECMO treatment could be avoided due to the pronounced improvement in gas exchange seen after the initiation of NO administration. The remaining 4 patients failed to respond to NO administration. One patient developed methaemoglobinaemia (13.9%) which required treatment with methylthionine. Since we were unable to produce any beneficial effect of NO in the late phase of the pulmonary disease process, we believe that, in order to be successful, inhaled NO should be instituted when conventional treatment has failed and the administration of an iv vasodilator is usually considered.     

Faecal interleukin-8 and tumour necrosis factor-alpha concentrations in cystic fibrosis

Interleukin-8 (IL-8) and tumour necrosis factor-alpha (TNF-alpha) concentrations were measured in faecal samples from nine patients with cystic fibrosis and nine healthy age matched controls. The patients were assessed with Shwachman score, apparent energy absorption, pancreatic enzyme dosage, simple spirometry, and presence of pseudomonal colonisation. Median (range) wet stool IL-8 and TNF-alpha concentrations in patients were 32,113 pg/g (21,656-178,128) and 3187 pg/g (368-17,611) respectively, compared with < 43.5 pg (IL-8)/g (< 22-4079) and 99 pg (TNF-alpha)/g (< 0.26-231) in controls. IL-8 concentration was negatively correlated with Shwachman score (r = -0.79) and pancreatic enzyme dosage (r = -0.77), but not with energy absorption. Seven patients were mature enough to cooperate with spirometry. Their IL-8 concentrations correlated with percentage predicted forced expiratory volume in one second (r = -0.78). IL-8 concentration was greater in four patients with, than five without, established pseudomonal colonisation: median difference 134,583 pg/g. TNF-alpha concentration was not correlated with measures of disease severity. Faecal IL-8 concentration might reflect the severity of pulmonary inflammation in cystic fibrosis and could provide an easily obtainable marker of disease activity.     

Prospective study of fetal heart rate and rhythm patterns

The fetal heart beat, detected by ultrasound, was recorded for five minutes from 934 antenatal women--266 at 30 to 35 weeks' gestation and 718 at 36 to 41 weeks. Episodes of bradycardia < 100/minute ranging from 5-30 seconds' duration occurred in 3 (1.1%) of the former and in 9 (1.3%) of the latter group. Tachycardia > 180/minute ranging from 30-90 seconds' duration occurred in 1 (0.4%) of the former and in 4 (0.6%) of the latter. Premature beats were not detected between 30 and 35 weeks, but occurred in 12 (1.7%) of 720 at 36 to 41 weeks' gestation. 50 subjects were monitored at both 30 and 35 weeks and 36 to 41 weeks' gestation and in one woman premature beats were present in the latter but not in the former recording. The incidence (1.7% of premature beats in the fetus at 36 to 41 weeks' gestation was similar to that in the healthy neonate (0.8%). Recordings of arrhythmias or rates outside the range 100-180/minute were replayed through a standard antepartum fetal heart rate monitor. The monitor failed to detect premature beats, 2 to 4 episodes of tachycardia > 180/minute, and 9 of 12 episodes of bradycardia < 100/minute, stressing its unreliability for detecting rapidly changing rates.