维生素A阻抑大鼠实验性肝纤维化的病理研究

利用光镜、电镜、免疫组化和形态学定量技术动态研究维生素A对大鼠四氯化碳肝纤维化的抑制作用。结果表明,维生素A可减少四氯化碳中毒大鼠肝内纤维连接蛋白和Ⅰ、Ⅲ型胶原沉积,抑制贮脂细胞向成纤维细胞转化,并可明显地减轻肝纤维化程度。本文还对维生素A抑制肝纤维化的机理及意义作了初步探讨。     

Patient and parental attitudes toward genetic screening and its implications at an adult cystic fibrosis centre

General population screening for cystic fibrosis carrier status in the United Kingdom would detect 72% of at-risk couples. Proper counselling would allow these couples to make informed reproductive choices, including the possibility of prenatal diagnosis and the termination of an affected pregnancy. However, children with cystic fibrosis born in this decade, given optimum treatment, now have an average life expectancy of 40 years, and there is no unanimity of opinion on how, where, when, or even if, screening should be offered. The purpose of this questionnaire-based study was to examine the attitudes of an adult clinic population who have grown up with cystic fibrosis, and of their parents, towards genetic screening programmes and the controversies and ethical dilemmas surrounding such programmes in cystic fibrosis. Both patients and parents supported prenatal screening (88% and 90%) and the option of terminating an affected pregnancy (68% and 84%). Only 22% of patients and 10% of parents felt that screening should be limited to families with a history of cystic fibrosis, and 19% and 6%, respectively, that prenatal diagnosis should be restricted to those with a previous child with cystic fibrosis. Despite the negative aspects of any screening programme and the acknowledged ethical problems peculiar to cystic fibrosis, the conclusion of our patients and parents who have lived intimately with the illness is that there should be the option of utilising information available from genetic screening for cystic fibrosis to guide reproductive choices. Pilot programmes to define the optimum management of such screening should continue.     

Diagnosis of allergic bronchopulmonary aspergillosis (ABPA) in cystic fibrosis

BACKGROUND: The diagnosis of allergic bronchopulmonary aspergillosis (ABPA) in cystic fibrosis (CF) patients may be difficult to establish because ABPA shares many characteristics with coexisting atopy or other lung infections in these patients. This study aimed to evaluate the sensitivity and specificity of various paraclinical parameters in the diagnosis of ABPA in patients with CF. METHODS: Accumulated data from a 5-year period in 238 CF patients were used to divide patients into two groups designated the ABPA group (n=26) and the non-ABPA group (n = 35). Patients in both groups were colonized with Aspergillus fumigatus (Af.), but only the ABPA group consistently demonstrated specific IgE antibodies and specific precipitins. Patients without A. fumigatus colonization were not assigned to either of these groups (n = 177). By this selection as the true diagnosis, 10 patients were selected from the ABPA group and 10 patients from the non-ABPA group. RESULTS: The groups were comparable as to age, sex, lung function (P=0.6), and presence of chronic Pseudomonas aeruginosa infection (P>0.1). No significant difference between the groups in unspecific atopic parameters such as eosinophil count (P=0.9) or eosinophil cationic protein (ECP) in sputum, plasma, or serum (P=0.9, P=0.59, and P = 0.9, respectively) was demonstrated. Total IgE was significantly higher in the ABPA group (P<0.01). The groups were comparable in skin prick test (SPT) positivity to a standard panel of aeroallergens (pollen, dander, molds, and mites) (P>0.2). Statistically significantly higher levels in the ABPA group were demonstrated in specific IgE to Af. (P < 0.05), SPT positivity to Af. (P < 0.02), and Af. precipitins (P < 0.05). Histamine release (HR) to Af. tended to be higher (P=0.075) in the ABPA group. Specific IgE to Af. was determined by Magic Lite (ML), CAP, and Maxisorp (in-house RAST). The CAP level was one to two classes higher than the ML level; however, the results were comparable (r=0.66, P<0.005). IgE to Af. measured by CAP was the test which offered the highest positive predictive value (PPV) and negative predictive value (NPV). Optimal diagnostic cutoff levels for the diagnosis of ABPA were determined: class 2 for HR to Af., 200 kIU/l for total IgE, and 3.5 (titer) for precipitating antibodies to Af., and class 2 for IgE to Af. (by CAP System). CONCLUSIONS: Unspecific atopy markers were of limited value for the diagnosis of ABPA. Patients with ABPA do not seem to be more atopic to other aeroallergens than non-ABPA patients. The most valid parameters for the diagnosis of ABPA in CF are SPT to Af., IgE to Af. in combination with precipitating antibodies to Af., and/or total IgE.     

Effects of Culture Medium on Cystic Fibrosis and Normal Fibroblasts Studied by X-Ray Microanalysis

The effect of culture medium from fibroblast cultures of cystic fibrosis (CF) patients and healthy controls on the elemental composition of fibroblasts was investigated by X-ray microanalysis. Exposure of normal fibroblasts to culture medium from CF fibroblasts caused an increase in calcium level. Exposure of CF fibroblasts to culture medium from normal cells caused an increase of the sodium content of CF cells to approximately normal levels; the calcium level of the CF fibroblasts, however, remained abnormally high. The results may indicate that CF fibroblasts lack a factor needed for the regulation of sodium transport. CF fibroblast medium apparently contains a factor that interferes with the regulation of calcium transport.     

Modulation of osteopontin in proteinuria-induced renal interstitial fibrosis

Proteinuria is associated with macrophage-dependent interstitial fibrosis (IF). Osteopontin (OPN), a macrophage chemoattractant, may be involved in the transition of proteinuria to IF but protective properties have also been reported. To elucidate whether OPN may be involved in the proteinuria-induced cascade of tubulointerstitial damage, renal expression of OPN was studied during the development of proteinuria-induced renal damage and during anti-proteinuric intervention with ACE inhibition (ACEi). First, the temporal relationships between proteinuria, interstitial OPN induction, and IF in adriamycin nephrosis (AN), a model of chronic proteinuria-induced renal damage, were studied. Second, the effect of anti-proteinuric treatment on OPN expression was investigated. The time course of OPN induction and markers of renal damage was studied in rats with unilateral AN at 6-week intervals until week 30. In a second study, a renal biopsy was taken 6 weeks after induction of bilateral AN; subsequently, rats were treated with ACEi until termination (week 12). In unilateral AN, proteinuria developed gradually and stabilized at week 10. In proteinuric kidneys, OPN expression was induced from week 12 onwards. Simultaneously, a progressive increase in interstitial macrophages, alpha-smooth muscle actin (alpha-SMA), collagen type III, and focal glomerulosclerosis (FGS) was observed. In bilateral AN, ACEi reduced proteinuria and OPN protein and stabilized fibrosis. In untreated animals, OPN mRNA increased, with stable OPN protein and fibrosis and increased FGS. Thus, in AN, development of proteinuria is followed by up-regulation of OPN along with markers of renal damage. The up-regulation of OPN is reversible by anti-proteinuric treatment without a corresponding reduction in fibrosis. Whereas these data are consistent with a role for OPN in the cascade of transition from proteinuria to fibrosis, intervention with ACEi showed that reduction of OPN does not attenuate established fibrosis.     

Changes in the infectivity, pyruvate kinase activity, acid phosphatase activity and P-glycoprotein expression in glibenclamide-resistant Leishmania mexicana

We previously demonstrated susceptibility of Leishmania sp. to glibenclamide, a K⁺-ATP transport blocker which interacts with members of the superfamily of adenosine 5′ triphosphate-binding cassette transporters. In order to characterize the molecular differences between a sensitive Leishmania strain, NR(Gs), and an experimentally selected glibenclamide-resistant strain, NR(Gr), specific biochemical and functional parameters have been evaluated both in the wild type and in the resistant strain. Most noteworthy, NR(Gr) exhibit an increased expression of P-glycoprotein and a decreased activity of functional key enzymes such as acid phosphatase, a prominent virulent factor of the parasite, and pyruvate kinase, a key control enzyme for both carbohydrate and protein metabolism. The specific biochemical, metabolic and functional changes observed in the resistant strain correlated with a reduced infectivity of stationary phase NR(Gr) in J774 macrophages and suggested a mechanism to overcome the effect of glibenclamide. Received: 21 January 2000 / Accepted: 1 March 2000     

COX-2+ myofibroblasts may play a key role in marked stromal fibrosis in strictured colorectal carcinomas

AIMS: To elucidate the mechanism of marked stromal fibrosis in strictured colorectal carcinomas (SC) that cause complete ileus. METHODS AND RESULTS: Sixteen cases of SC and 29 cases of non-strictured colorectal carcinoma (NSC) were studied. These carcinomas showed similar clinicopathological features except for bowel stricture. The stricture index (SI) showing the degree of bowel stricture was 59.8 +/- 12.1% in SC versus 20.8 +/- 24.6% in NSC (P < 0.001). The fibrosis index (FI), defined to reflect the extent of stromal fibrosis, was 56.3 +/- 8.8% in SC versus 21.9 +/- 10.6% in NSC (P < 0.001). COX-2+ myofibroblasts were detected in 13 cases (81.3%) in SC versus eight cases (27.6%) in NSC (P < 0.01). The COX-2+ myofibroblast density was 276.7 +/- 181.1 cells/mm(2) in SC versus 26.6 +/- 52.7 cells/mm(2) in NSC (P < 0.001). When all cases were divided into two groups with and without COX-2+ myofibroblasts, the SI was 48.8 +/- 19.1% in those with COX-2+ myofibroblasts versus 24.8 +/- 29.3% in those with COX-2- myofibroblasts (P < 0.001). CONCLUSION: COX-2+ myofibroblasts may play an important role in extensive bowel stricture in colorectal carcinomas.     

Family functioning in school-age children with cystic fibrosis: an observational assessment of family interactions in the mealtime environment

OBJECTIVE: To examine, using direct observation methodology, differences in family functioning at mealtime between families of school-age children with cystic fibrosis (CF) and families of school-age children without a chronic illness. METHOD: Family functioning was rated using the McMaster Mealtime Interaction Coding System (MICS) during a videotaped dinner among 28 families of children with CF and 27 families of non-ill, age-matched peers. Families were rated on overall family functioning and on six dimensions of the MICS: task accomplishment, communication, affect management, interpersonal involvement, behavior control, and role allocation. RESULTS: Ratings for families of a child with CF were significantly lower than they were for comparison families on overall family functioning and on four of the six MICS dimensions: communication, affect management, interpersonal involvement, and behavioral control. Moreover, a significantly greater percentage of families of children with CF were rated in the unhealthy range on overall family functioning and on five of six MICS dimensions. There was no relationship between family functioning and child weight status for children with CF. CONCLUSIONS: The current study suggests that for families of school-age children with CF, the family system is negatively affected during mealtime. Dietary interventions need to address family-centered, as well as child-centered, interventions to help families manage challenges presented during the family meal.     

Properties and regulation of chloride channels in cystic fibrosis and normal airway cells

The present study examines the properties of Cl^–channels in cultured respiratory cells of cystic fibrosis (CF) patients and normal (N) individuals. In excised membrane patches the conductances for CF and N Cl^– channels were larger at positive as compared to negative clamp voltages (V _c): 74±2.6 (V _c > 0) and 47±2.0 pS (V _c < 0) for CF (n= 57) and 69±3.6 (V _c > 0) and 45±2.3 pS (V _c < 0) for N (n=35). The open probability (P _o) of the channel increased markedly with depolarization. Both the voltage dependence of the conductance and of P _o contribute to the outward rectification of the channel. The time histogram analysis reveals two open and two closed time constants. The selectivity of the channel was Cl^–=Br^– =I^– > NO ₃ ^– gluconate. The channel was inhibited reversibly by 5-nitro-2-(3-phenylpropylamino)-benzoate (NPPB) at 10^–7 mol/l to 10^–5 mol/l. While Cl^– channels were present in cell attached patches of N cells, they were absent in those of CF cells. The mean conductance for cell attached (N) Cl^– channels was 76±3.2 pS for positive clamp voltages (V _c) and 46±3.9 pS for negative V _c (n=8). When the membrane patches were excised from CF cells Cl^– currents appeared spontaneously (n=19). The immediate appearance (within 1 s) of Cl^– channels after excision was observed at positive (n=6) as well as at negative clamp voltage (n=13). Excision activation of CF Cl^– channels was observed at low (< 10^–9 mol/l) or high (10^–3 mol/l) calcium activities on the cytosolic side of the excised patch. Variation of the Ca⁺ activity (< 10^–9–10^–3 mol/l) or pH (6.5–8.5) on the cytosolic side exerted no effects on these Cl^– channels. These results suggest that Cl^– channels are present in the apical membrane of CF and N respiratory cells but they seem to be inhibited in intact CF cells. Excision of the patch and hence removal of the cytosolic inhibitor leads to an activation of Cl^– channels. The Cl^– channels in excised patches of N and CF cells have identical properties.