[Clinical analysis of 4 children with cryptogenic organizing pneumonia].

Objective: To analyze the clinical features of children with cryptogenic organizing pneumonia (COP) confirmed by pathology. Methods: The clinical manifestations, imaging, pathology, treatment and outcome data of 4 children with COP confirmed by thoracoscopic lung biopsy were retrospectively analyzed, who were hospitalized at Respiratory Department of Shenzhen Children's Hospital from January 2004 to December 2022. Results: All of the 4 patients were male, the age ranged from 1 year 3 months to 14 years. The time from onset to diagnosis was 3 months to 3 years. The follow-up duration was 6 months to 6 years. All the 4 cases had cough, 2 cases had tachypnea and wheezing, 1 case had expectoration, 1 case had chest pain, 1 case had decreased activity tolerance and weight loss. Rales in 2 cases and hypoxemia in 1 case. Pulmonary high resolution CT showed diffuse distribution, involvement of both lungs in 3 cases, and single lung combined migration in 1 case.Three cases showed ground-glass opacity, consolidation, patchy or fibrous strips, and 1 case presented air bronchogram and "reversed halo sign". All the 4 cases were performed thoracoscopic lung biopsy, and the pathological findings showed cellulose exudate or small nodules filled with granulation tissue or fibroblasts in the alveolar cavity and small airways, and 1 case was Masson corpuscle positive. Three patients achieved remission after glucocorticoid therapy. Spontaneous remission without treatment was seen in 1 patient.Two cases were followed up for 17 months and 6 years, respectively, who had excellent outcome. Conclusions: The manifestations of COP in children include cough, expectoration and chest pain. Infants and young children may have tachypnea and wheezing. The most common chest CT findings are diffuse distribution of ground-glass opacity, patchy and consolidation in both lungs. Diagnosis should depend on pathological examination. The effect of glucocorticoid therapy is good.

[Immunodeficiency diseases with interstitial lung disease as major clinical manifestations: report of six cases].

Objective: To summarize the clinical features of immunodeficiency diseases with interstitial lung disease (ILD) as major clinical manifestations and to improve understanding etiology of ILD. Methods: The clinical features and clinical clues for diagnosis of six cases with immunodeficiency presented with ILD in Shenzhen Children's Hospital from January 2014 to December 2016 were retrospectively analyzed. Results: The patients' age ranged from 3 months to 5 years and 9 months, 5 cases were male. All cases had cough and tachypnea, 3 cases had lung infection and respiratory failure, 2 cases had chronic hypoxia and one had clubbing. Three cases had skin rashes; 5 cases had failure to thrive. Chest CT scan showed diffuse ground glass opacity in all the 6 cases, and 2 cases had cystic changes and one had "crazy-paving" pattern. Five patients were suspected to have surfactant dysfunction and genetic testing was performed before diagnosis of immunodeficiency, of which the results were negative. With human immunodeficiency virus antibody test or immunologic laboratory testing and/or immune genetic panel, acquired immune deficiency syndrome was confirmed in one case, hyper-IgM syndrome was confirmed in two cases and hyper-IgE syndrome in one case, Wiskott-Aldrich syndrome in one and STAT3 gain of function genetic mutation in another. All cases had clinical clues indicative of underlying immunocompromise. Conclusions: The clinical features of immunodeficiency diseases with ILD are cough, tachypnea or hypoxia, respiratory failure with infection, diffuse ground glass opacity in Chest CT imaging. With thorough medical history and immunology screening, there would be clinical clues indicative of underlying immunocompromise. Screening for immunodeficiency disease should be emphasized in the differential diagnosis of ILD, otherwise it may lead to misdiagnosis or unnecessary testing.

[Retracted: Clinical and epidemiological characteristics of 34 children with 2019 novel coronavirus infection in Shenzhen].

Objective: To describe the characteristics of clinical manifestations and epidemiology of children with 2019 novel coronavirus (2019-nCoV) infection. Methods: All 34 children with laboratory-confirmed 2019-nCoV infection by quantitative real-time reverse transcription-PCR through nasopharyngeal swab specimens were admitted to the Third People's Hospital of Shenzhen from January 19 to Febuary 7, 2020. Clinical data and epidemiological history of these patients were retrospectively collected and analyzed. Results: Among the 34 cases, 14 were males, and 20 were females. The median age was 8 years and 11 months. No patients had underlying diseases. There were 28 children (82%) related with a family cluster outbreak. There were 26 children (76%) with a travel or residence history in Hubei Province. These patients could be categorized into different clinical types, including 22 (65%) common cases, 9 (26%) mild cases and 3 (8.8%) asymptomatic cases. No severe or critical cases were identified. The most common symptoms were fever (17 cases, 50%) and cough (13 cases, 38% ). In the 34 cases, the white blood cell counts of 28 cases (82%) were normal. Five cases had white blood cell counts more than 10×10(9)/L. One case had white blood cell counts less than 4×10(9)/L. Neutropenia and lymphopenia was found in one case, respectively. C-reactive protein levels and erythrocyte sedimentation rates were elevated in 1 and 5 case, respectively. Elevated procalcitonin was found in 1 case and D-Dimer in 3 cases. The levels of lactic dehydrogenase (LDH) were more than 400 U/L in 10 cases. The CT images of these patients showed bilateral multiple patchy or nodular ground-glass opacities and/or infiltrating shadows in middle and outer zone of the lung or under the pleura. Twenty patients were treated with lopinavir and ritonavir. Glucocorticoids and immunoglobulin were not used in any cases. All the cases improved and were discharged from hospital. Further following up was need. Conclusions: The clinical manifestations in children with 2019-nCoV infection are non-specific and are milder than that in adults. Chest CT scanning is heplful for early diagnosis. Children's infection is mainly caused by family cluster outbreak and imported cases. Family daily prevention is the main way to prevent 2019-nCoV infection.

[Analysis of clinical effects of artificial dermis in functional reconstruction in the late stage of extremely severe burn].

Objective: To explore the clinical effects of artificial dermis combined with autologous split-thickness skin transplantation in the treatment of functional reconstruction in the late stage of extremely severe burn. Methods: From May 2015 to May 2017, medical records of 40 patients with limited activity after scar hyperplasia and conforming to the study criteria, injured in August 2nd Kunshan factory aluminum dust explosion accident in 2014, and had surgeries in our hospital and rehabilitation treatment in our hospital's alliance rehabilitation hospital, Rehabilitation Hospital of Kunshan Zhou City, were retrospectively analyzed. According to the treatment methods, 20 patients (12 males and 8 females, aged 20 to 45 years) were enrolled in artificial dermis group. They were conducted with stage Ⅰ functional site scar loosening and artificial dermis (PELNAC) implanting+ stage Ⅱ transplantation of autologous split-thickness skin. Another 20 patients (14 males and 6 females, aged 20 to 45 years) were enrolled in conventional skin grafting group. They were conducted with stage Ⅰ functional site scar loosening and transplantation of autologous thin medium-thickness skin. After 5 days of autologous skin transplantation, the survival rates of autologous skin in patients of 2 groups were calculated. The autologous skin infection and complete healing time of skin grafting area in patients of 2 groups were recorded. In 3, 6, and 10 months after autologous skin transplantation, the Vancouver Scar Scale (VSS) was used to assess the scar condition of recipient site in patients of 2 groups. The complete healing time of donor site in patients of 2 groups was recorded. In 10 months after autologous skin transplantation, VSS was used to assess the scar condition of donor site in patients of 2 groups. In 12 months after autologous skin transplantation, the functional recovery of surgical function reconstruction site in patients of 2 groups was evaluated and rated. Data were processed with t test, analysis of variance for repeated measurement, Wilcoxon rank-sum test, chi-square test, Fisher's exact probability test, and Bonferroni correction. Results: (1) After 5 days of autologous skin transplantation, the survival rate of autologous skin in patients of artificial dermis group was (95±3)%, similar to (93±3)% in conventional skin grafting group (t=1.262, P>0.05). The results of autologous skin infection of patients in the 2 groups were similar (P>0.05). (2) After autologous skin grafting, the complete healing time of skin grafting area in patients of artificial dermis group was (12.3±2.5) d, similar to (12.7±2.0) d of conventional skin grafting group (t=-0.139, P>0.05). In 3, 6, and 10 months after autologous skin transplantation, the VSS scores of scars in recipient site of patients in artificial dermis group were significantly lower than those of conventional skin grafting group (t=-4.428, -5.655, -6.839, P<0.01). (3) After autologous skin grafting, the complete healing time of donor site in patients of artificial dermis group was obviously shorter than that in conventional skin grafting group (t=-12.435, P<0.01). In 10 months after autologous skin transplantation, the VSS score in donor site of patients in artificial dermis group was significantly lower than that of conventional skin grafting group (t=-16.971, P<0.01). (4) After 12 months of autologous skin transplantation, the functional improvement levels of the functional site of patients in artificial dermis group were good in 4 patients, fair in 15 patients, and bad in 1 patient, while the functional improvement levels of the functional site of patients in conventional skin grafting group were good in 5 patients, fair in 8 patients, and bad in 7 patients. The functional improvement levels of the functional site of patients between the two groups were similar (Z=371.5, P>0.05). Conclusions: Compared with conventional stage Ⅰ functional site scar loosening and transplantation of autologous thin medium-thickness skin, stage Ⅰ functional site scar loosening and artificial dermis implanting+ stage Ⅱ transplantation of autologous split-thickness skin does not affect the survival of skin in the early stage and can effectively improve functional site function, reduce VSS scores of donor site and recipient site, and shorten complete healing time of donor site.

[A novel compound heterozygous mutation in ABCA3 gene in a child with diffuse parenchymal lung disease].

Objective: To summarize the clinical characteristics of the diffuse parenchymal lung diseases in a child caused by a novel compound heterozygous ABCA3 mutation and explore the association between the phenotype and ABCA3 mutation. Method: The clinical material of a patient diagnosed with diffuse parenchymal lung disease with ABCA3 mutation in December 2016 in Shenzhen Children's Hospital was analyzed. The information about ABCA3 gene mutation updated before April, 2017 was searched and collected from the gene databases (including 1000Genomes, HGMD, EXAC) and the literatures (including Wanfang Chinese database and Pubmed). Result: The girl was one year and nine months old. She presented with chronic cough, tachypnea, cyanosis and failure to thrive since she was one year and three months old. Her condition gradually deteriorated after she was empirically treated. Physical examination showed malnutrition, tachypnea and clubbed-fingers. Her high resolution computed tomography (HRCT) revealed diffused ground-glass opacities, thickened interlobular septum, and multiple subpleural small air-filled lung cysts. The second generation sequencing study identified a novel compound heterozygous mutation (c.1755delC+c.2890G>A) in her ABCA3 gene, which derived respectively from her parents and has not been reported in the database and the literatures mentioned above. Conclusion: c.1755delC+c.2890G>A is a new kind of compound heterozygous mutation in ABCA3, which can cause children's diffuse parenchymal lung disease. Its phenotype is related to its genotype.

Population structure analysis and association mapping of blast resistance in indica rice (Oryza sativa L.) landraces.

Rice blast caused by Magnaporthe oryzae is one of the most devastating rice diseases worldwide. To understand the genetic diversity of indica landrace accessions and identify simple sequence repeat (SSR) markers that are associated with blast resistance, a population of 276 indica landraces from across the world was constructed. This population was then used to evaluate the blast-resistance phenotype through artificial inoculation under controlled conditions in 2012 and 2013. The genetic diversity and association of the population with resistance were analyzed by examining the phenotype for 160 SSR markers distributed on 12 rice chromosomes. The 276 accessions were classified into seven groups using model- and distance-based cluster analyses. Associations between SSR markers and blast resistance showed that 26 SSR markers were significantly associated with blast resistance in 2012 and 2013 (P < 0.01) and that the phenotypic variation ranged from 2.68 to 13.11%. Nineteen of the markers associated with blast resistance were located in regions where genes or quantitative trait loci (QTLs) have been previously reported, and seven were newly identified in this study. These results indicate that marker-trait association has potential advantages over classical linkage analysis and QTL mapping, and that these markers could be used for marker-assisted selection in rice blast-resistance-breeding programs.

Identification of quantitative trait loci conferring blast resistance in Bodao, a japonica rice landrace.

Bodao, a japonica landrace from the Taihu Lake region of China, is highly resistant to most Chinese isolates of Magnaporthe oryzea, a form of rice blast. To effectively dissect the influence of genetics on this blast resistance, a population of 155 recombinant inbred lines (F2:8) derived from a cross of Bodao x Suyunuo was inoculated with 12 blast isolates. Using a quantitative trait locus (QTL) mapping approach, 13 QTL on chromosomes 1, 2, 9, 11, and 12 were detected from Bodao. Five QTL, including qtl11-1-1, qtl11-3-7, qtl11-4-9, qtl12-1-1, and qtl12-2-3, have not been previously reported. The qtl11-3-7 and qtl11-4-9 may be the two main effective QTL and resistant to 7 and 9 isolates, respectively. The results of the present study will be valuable for the fine mapping and cloning of these two new resistance genes.

Comprehensive gene expression analysis of the DNA (cytosine-5) methyltransferase family in rice (Oryza sativa L.).

Cytosine DNA methylation is a conserved epigenetic regulatory mechanism in both plants and animals. DNA methyltransferases (DNA MTases) not only initiate (de novo) but also maintain the process of DNA methylation. Here, we characterized the genome-wide expression profiles of 10 cytosine DNA MTase genes belonging to 4 subfamilies, MET1, CMT, DNMT2, and DRM, in rice. Tissue-specific gene expression analysis showed that all family members varied widely in their expression and specificities and might be involved in some basic metabolic pathways. Similarly, the expression of all rice cytosine DNA MTase genes was not regulated by plant hormones except OsDRM1a and OsDRM1b, which were downregulated by jasmonic acid. The transcription level of 10 genes in rice shoots and roots was also measured under salt and osmotic stress. Meanwhile, quantitative polymerase chain reaction data of the japonica and indica rice cultivars revealed that there is large variation in the expression activities of all genes. The results provide a foundation to further explore the roles of DNA MTases and the epigenetic regulation of abiotic stress responses in rice.

Antioxidant enzyme levels in pathogenesis of oral squamous cell carcinoma (OSCC).

Increased oxidative stress and altered anti-oxidant defense systems have been implicated in the pathogenesis of several diseases including cancer. Therefore, the aim of our study is to evaluate the antioxidant enzyme levels such as superoxide dismutase (SOD) and catalase in blood samples and tissues collected from oral squamous cell carcinoma patients and compared with healthy controls.The collected blood samples and tumor tissues from the diseased individuals and the normal controls are analyzed for malondialdehyde (MDA) and nitric oxide (NO), which is the indicator of oxidative and nitrosative stress respectively. The anti-oxidant enzymes SOD and catalase levels are measured by UV visible spectrophotometer. Subsequently, immuno-histostaining for antioxidant enzymes were performed in oral squamous cell carcinoma biopsies and sections were analyzed.The levels of MDA and NO were significantly elevated in the blood and tissue samples of OSCC patients. The antioxidant enzymes SOD and catalase were significantly reduced in OSCC tissues; while in erythrocytes catalase level is reduced whereas the SOD level is increased. Further, the reduced immuno-histostaining was observed for catalase and SOD in OSCC tissues when compared to normal oral epithelium.The enhanced levels of MDA and NO revealed that increased oxidative stress in conjunction with the reduced antioxidant defense mechanism in OSCC patients, might be involved in cancer progression. Our results suggest that detection of reactive oxygen species (ROS) and antioxidant enzymes levels might be a valuable marker in cancer prognosis and for improving therapeutic strategies in oral cancer.

Trace mineral interactions in broiler chicken diets.

1. The aim of the present study was to demonstrate trace mineral interactions among organic copper, iron, manganese and zinc (Cu, Fe, Mn and Zn) in broiler chickens. 2. Three experiments were conducted using a control diet which was deficient in Cu, Fe, Mn and Zn. 3. In experiment 1, the control diet, supplemental organic Cu, Fe alone and combined diets, were randomly fed to 4 groups of one-day-old Cobb broilers (each group had 6 replicates of 4 birds). 4. In experiment 2, the control diet, supplemental organic Mn and Zn alone or combined with Cu, Fe diets and corresponding inorganic combined diet, were randomly fed to 6 groups (each group had 8 replicates of 6 birds). 5. In experiment 3, the depletion of organic Zn, the depletion of inorganic Zn and normal Zn treatments were carried out in three groups of one-day-old Cobb broilers (each group had 8 replicates of 6 birds). 6. Adding organic Cu, Fe and Mn alone or combined to Zn deficient diets did not significantly improve bird performance and were mostly excreted. Supplemental organic Zn alone or combined with other elements significantly increased feed intake, body weight gain and tibia bone length. However, supplemental organic Fe alone or combined with Cu significantly increased feed intake but had no obvious effect on body weight gain. The organic Fe supplementation resulted in a wider tibia. 7. Depletion of organic and inorganic Zn resulted in decreased feed intake, body weight gain and total tibia bone Zn content. Zinc deficiency did not affect the uptake of organic Fe by tibia bone but reduced its total Fe content. 8. Zinc is the first limiting element among these 4 trace minerals. Adding Mn, Cu and Fe to Zn deficient diets did not stimulate bird performance. Surplus organic Fe and Cu resulted in increased feed intake and increased tibia bone Fe content but did not contribute to bird performance.

Effect of potassium diformate on growth performance and gut microbiota in broiler chickens challenged with necrotic enteritis.

1. The effect of potassium diformate (KDF) on mortality, growth performance, microbial populations, pH and short chain fatty acid concentrations in the intestinal tract of broiler chickens challenged with necrotic enteritis was investigated. 2. An experiment with 1050 Cobb male broiler chickens was conducted from 1 to 35 d of age. There were 7 treatment groups: (1) unchallenged negative control, (2) unchallenged KDF (4.50 g/kg feed), (3) challenged negative control, (4) challenged positive control (100 ppm monensin and 45 ppm Zn-bacitracin), and (5) to (7) challenged KDF (inclusion rate 2.25, 4.50 and 6.75 g/kg feed, respectively). 3. The necrotic enteritis challenge caused significant growth depression except in the challenged positive control group. Inclusion of KDF in feed had no significant effect on weight gain or feed conversion ratio, neither under challenged nor unchallenged conditions. Necrotic-enteritis-related mortalities were reduced in response to the positive control feed and KDF at 2.25 and 4.50 g/kg rates, but with no effect at the 6.75 g/kg rate. 4. There was no effect of KDF on Clostridium perfringens numbers in jejunum during the necrotic enteritis challenge (d 15). Post challenge (d 35), 4.5 g/kg KDF reduced the number of C. perfringens and Enterobacteria in jejunum compared with the negative control group. 5. Intestinal pH was not affected by adding KDF to the feed. The challenge reduced jejunum pH compared with the unchallenged treatment groups and challenged positive control group. 6. Chickens fed the KDF diets had detectable concentrations of formic acid in the jejunum. There was a tendency towards higher concentrations of acetic acid and lactic acid in the small intestine of unchallenged birds, whereas challenged birds had higher concentrations of butyric acid in the caeca. 7. It is concluded that KDF holds promise as an agent to control necrotic enteritis in broiler chickens and it may be possible to enhance the efficacy of KDF by manipulating dietary properties that may influence the dissociation kinetics of KDF in the gut.

Optimal dietary inclusion of organically complexed zinc for broiler chickens.

1. The aim of the present study was to determine the optimal content of organically complexed zinc (Zn) for broiler chickens. 2. Five different Zn and manganese (Mn) dietary contents from organically complexed supplements including a control diet containing 15 mg Mn and 20 mg Zn/kg diet, were randomly fed to one-day-old Cobb broilers (each treatment had 6 replicates of 4 birds) for 35 d. Body weight and feed intake were recorded weekly. At the end of the experiment, two birds from each cage were killed and their right tibia were collected to measure bone size, strength and mineral contents. 3. Body weight gain and total tibia copper (Cu), iron (Fe), Mn and Zn contents increased linearly with supplemental Zn and Mn intake. The optimal Zn requirements for broilers at 1-14 and 14-35 d of age were 58 and 68 mg/kg diet, respectively. 4. Supplementation of Mn and Zn had no effect on tibia bone width and strength, but increased tibia length. 5. In commercial practice, organically complexed Zn may need to be supplemented during the entire period of production at a higher content than NRC recommendation but it is not necessary to exceed 70 mg/kg diet.

Protocatechuic acid suppresses MPP+ -induced mitochondrial dysfunction and apoptotic cell death in PC12 cells.

Protocatechuic acid (PCA), a phenolic compound isolated from the kernels of Alpinia (A.) oxyphylla, showed antioxidant neuroprotective effect in our previous study. Here, we investigated the effect of PCA on the MPP(+)-induced mitochondrial dysfunction and apoptotic cell death in PC12 cells. The apoptosis in MPP(+)-induced PC12 cells was associated with loss of mitochondrial membrane potential, the formation of reactive oxygen species (ROS), GSH depletion, activation of caspase-3 and down-regulation of Bcl-2. In contrast, treatment of PC12 cells with PCA significantly prevented the above-mentioned mitochondrial dysfunction. Our data pointed to the potential clinical application/use of PCA to overcome neurodegenerative diseases such as Parkinson's disease.

Protocatechuic acid from Alpinia oxyphylla against MPP+-induced neurotoxicity in PC12 cells.

An ethyl acetate extract of Alpinia oxyphylla was found to possess neuroprotective activity against 1-methyl-4-phenylpyridinium ion (MPP(+)) induced apotosis and oxidative stress in cultured PC12 cells. From the extract, a phenolic compound was isolated through bioassay-guided fractionation and identified as protocatechuic acid (PCA) by IR, MS, and (1)H and (13)C NMR spectroscopy. It was the first time which was isolated from the kernels of A. oxyphylla. Exposure of PC12 cells to 1mM MPP(+) may cause significant viability loss and apoptotic cell death. PCA stimulated PC12 cellular proliferation and markedly attenuated MPP(+)-induced apoptotic cell death in a dose-dependent manner. By observing the nuclear morphological changes and flow cytometric analysis, PCA showed its significant effect on protecting PC12 cells against MPP(+)-induced apoptosis. Meanwhile, PCA enhanced the activities of superoxide dismutase (SOD) and catalase (CAT) in PC12 cells. In addition, PCA also dose-dependently reduced the hydrogen peroxide (H(2)O(2))- or sodium nitroprusside (SNP)-induced cell death in PC12 cells. The results suggest that PCA may be one of the primary active components in the kernels of A. oxyphylla and provide a useful therapeutic strategy for the treatment of oxidative stress-induced neurodegenerative disease such as Parkinson's disease.

Catalpol inhibits apoptosis in hydrogen peroxide-induced PC12 cells by preventing cytochrome c release and inactivating of caspase cascade.

In the present study, using a rat pheochromocytoma (PC12) cell line, the effect of catalpol on H2O2-induced apoptosis was studied. The apoptosis in H2O2-induced PC12 cells was accompanied by down-regulation of Bcl-2, up-regulation of Bax, the release of mitochondrial cytochrome c to cytosol and sequential activation of caspase-1 and caspase-3 then leading to cleavage of poly-ADP-ribose polymerase (PARP). Catalpol not only suppressed the down-regulation of Bcl-2, up-regulation of Bax and the release of mitochondrial cytochrome c to cytosol, but also attenuated caspase-3 activation, PARP cleavage, and eventually protected against H2O2-induced apoptosis. Taken together, these results suggest that treatment of PC12 cells with catalpol can block H2O2-induced apoptosis by the regulation of Bcl-2 family members, as well as suppression of cytochrome c release and caspase cascade activation.

Hydrogen peroxide-induced apoptosis in pc12 cells and the protective effect of puerarin.

In this study, the effect of puerarin on hydrogen peroxide-induced apoptosis in PC12 cells was studied. Exposure of cells to 0.5mM H(2)O(2)may cause significant viability loss and apoptotic rate increase. When c-Myc, Bcl-2 and Bax expression and caspase-3 activity were measured, using Ac-DEVD-AMC as a substrate, the changes in these apoptosis regulatory and effector proteins suggested that the elevation of c-Myc, decrease in Bcl-2:Bax protein ratio, and caspase-3 activation all play a key role in apoptosis. When cells were treated with puerarin prior to 0.5 mM H(2)O(2)treatment, a reduction in viability loss and apoptotic rate was seen. In addition, c-Myc expression decreased and Bcl-2:Bax ratio increased. Puerarin also reduced the H(2)O(2)-induced elevation of caspase-3 activation. These results suggest that puerarin can protect neurons against oxidative stress. It can block apoptosis in its early stages via the regulation of anti- and pro-apoptotic proteins, as well as by the attenuation of caspase-3 activation in H(2)O(2)-induced PC12 cells.

Effect of ischemic preconditioning on hepatic tolerance to cold ischemia in the rat.

A short warm ischemia before reperfusion has been shown to improve the tolerance of the heart and the liver to a prolonged warm ischaemia. The present experimental study was conducted to evaluate the effect of such preconditioning on hepatic tolerance to an extended cold ischemia. In a model of isolated perfused liver, livers from Wistar rats (250-350 g) were stored for 24 h in UW (4 degrees C) immediately after harvesting and reperfused for 3 h at 37 degrees C. Control livers subjected to a 24-h cold ischemia were compared to livers subjected to preconditioning (defined as a 5- or 10-min clamping of the hepatic pedicle followed by a 10-min reperfusion before liver harvesting) prior to the definitive 24-h cold ischemia. While there was no difference in bile production between the preconditioned groups and the controls, transaminases and LDH release was significantly increased, vascular resistance was enhanced, and preservation injury was more extensive in both preconditioned groups as compared to controls. In contrast to the beneficial effect reported on prolonged warm ischaemia, preconditioning has a deleterious effect on hepatic tolerance to an extended cold ischemia.