Silver nanoparticles enhanced enzyme-linked immunosorbent assay (ELISA) detection of cancer testis antigens (CTAs).

OBJECTIVE: The Enzyme-Linked Immunosorbent Assay (ELISA) has been a cornerstone technique in laboratory medicine for over 55 years, relying on the specific binding of antibodies to antigens. ELISA's widespread use stems from its ability to detect low concentrations, its specificity, reproducibility, and potential for high-throughput screening. However, its sensitivity has limitations, prompting the exploration of innovative methods to improve the limit of detection (LOD). Nanoparticles provide a promising platform for enhancing ELISA sensitivity. Due to their high surface-to-volume ratio, they offer increased binding sites for capture elements and reporting tags, leading to amplified analytical signals. Recent studies have demonstrated improved sensitivity in ELISA through nanoparticle application, yielding faster detection times and enhanced sensitivities. This study investigates the potential of 50 nm citrate-capped silver nanoparticles to enhance ELISA's performance in quantifying cancer testis antigens (CTAs). PATIENTS AND METHODS: In our study, we used the Human NY-ESO-1 ELISA kit (for research purposes) to determine the concentration of CTAs in randomly selected samples from healthy (n=89) and oncological (n=80) subjects, aged 18-75. We employed 50 nm citrate-capped silver nanoparticles (AGCB50-1M, BioPure Silver Nanoparticles - bare citrate, nano-Composix, San Diego, CA, USA). ELISA reactions followed the manufacturer's instructions, and data processing aligned with the same guidelines. Absorbance (OD) measurements occurred at 450 nm, influencing nanoparticle selection. Each ELISA well contained 5 ml of nanoparticles' stock solution with specified concentrations. CTAs concentrations were derived from the standard curve through CurveExpert Basic software. Statistical analysis was performed using SPSS v. 27 software, with p-values indicating significance if <0.03. The study adhered to Helsinki Declaration principles and received ethical approval. Participants provided informed written consent. RESULTS: The increased concentration values of CTAs for healthy individuals and cancer patients were determined in the case of the application of silver nanoparticles. CONCLUSIONS: The usage of nanoparticles can enhance the sensitivity of the ELISA method and positively influence its specific detection limit.

Exposure to pesticides and pediatric Wilms' tumor. A meta-analysis on pre-conception and pregnancy parental exposure with an IARC/WHO commentary.

BACKGROUND: There are hereditary types of nephroblastoma or Wilms' tumor associated with exposure of the germ cells of either parent to harmful environmental factors. Some studies have examined the exposure of compounds used pesticides and herbicides as a risk factor for Wilms' tumor. METHODS: A systematic review and meta-analysis were carried out on case-control studies to establish the potential link between exposure to these organic molecules and Wilms' tumor occurrence in children rigorously. We examined the monographs on some organo-phosphate insecticides and herbicides issued by the International Association for the Research on Cancer (IARC) under the auspices of the World Health Organization (WHO). PUBMED, SCOPUS, and Google Scholar studies (1960-2021) were identified and systematically reviewed following Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Subgroup analyses were conducted after stratification for occupational versus residential exposure and before birth (prenatal) vs. after birth (postnatal) exposure. In addition, we revised the monographs on chemical compounds issued recently by the IARC/WHO. RESULTS: Our findings seem to consolidate that parental pesticide exposure during the preconception or pregnancy period is correlated with an increased occurrence risk for Wilms' tumor. We confirm the validity of the WHO essays on certain organophosphate herbicides and insecticides, which support these compounds, may be highly relevant in future cancer prevention policies. CONCLUSION: Parental exposure to pesticides, particularly in household settings, is poorly emphasized in our society. There is a strong association between these organophosphate compounds and pediatric cancer. Public health agencies may need to take stronger action than in the past.

Real-world outcomes according to treatment strategies in ALK-rearranged non-small-cell lung cancer (NSCLC) patients: an Italian retrospective study.

PURPOSE: Anaplastic lymphoma kinase (ALK) rearrangement confers sensitivity to ALK inhibitors (ALKis) in non-small-cell lung cancer (NSCLC). Although several drugs provided an impressive outcome benefit, the most effective sequential strategy is still unknown. We describe outcomes of real-life patients according to the treatment strategy received. PATIENTS: We retrospectively collected 290 ALK rearranged advanced NSCLC diagnosed between 2011 and 2017 in 23 Italian institutions. RESULTS: After a median follow-up of 26 months, PFS for crizotinib and a new generation ALKis were 9.4 [CI 95% 7.9-11.2] and 11.1 months [CI 95% 9.2-13.8], respectively, while TTF were 10.2 [CI 95% 8.5-12.6] and 11.9 months [CI 95% 9.7-17.4], respectively, being consistent across the different settings. The composed outcomes (the sum of PFS or TTF) in patients treated with crizotinib followed by a new generation ALKis were 27.8 months [CI 95% 24.3-33.7] in PFS and 30.4 months [CI 95% 24.7-34.9] in TTF. The median OS from the diagnosis of advanced disease was 39 months [CI 95% 31.8-54.5]. Patients receiving crizotinib followed by a new generation ALKis showed a higher median OS [57 months (CI 95% 42.0-73.8)] compared to those that did not receive crizotinib [38 months (CI 95% 18.6-NR)] and those who performed only crizotinib as target agent [15 months (CI 95% 11.3-34.0)] (P < 0.0001). CONCLUSION: The sequential administration of crizotinib and a new generation ALKis provided a remarkable clinical benefit in this real-life population, being an interesting option to consider in selected patients.

Diagnostic value of PET/CT in differentiating benign from malignant solitary pulmonary nodules.

PURPOSE: Solitary pulmonary nodules (SPNs) are round or oval lesions with a clear border with the surrounding parenchymal tissue and a radiologic diameter smaller than 3 cm which are not associated with atelectasis, pneumonia, lymphadenopathy, or chest wall pathologies. The purpose of the present study was to evaluate the efficacy of positron emission tomography (PET) / computerized tomography (CT) in differentiating benign from malignant SPNs. METHODS: In this retrospective study, 209 patients, who were diagnosed with SPN by thoracic CT and demonstrated positive or negative results for malignancy in the PET/ CT examination between January 2007 and June 2010, were enrolled. Among the 91 patients who gave consent for interventional procedures, performed were bronchoscopic endobronchial biopsy in 10, transbronchial biopsy in 15, bronchoscopic brushing in 4, transthoracic needle biopsy in 11, video-assisted thoracoscopy (VATS) in 4, lobectomy in 22, pneumonectomy in 2, and wedge resection in 23. The materials were histopathologically examined. RESULTS: 129 (61.72%) of the SPN cases were benign and 80 (38.27%) malignant. The mean SUVmax value for the benign SPNs was 2.06 ± 3.29 and 7.39±5.69 for the malignant SPNs (p=0.000). Positive correlation was found between the nodule diameter and risk for malignancy. A SUVmax value of 4 was found to have the best sensitivity and specificity. CONCLUSION: PET/CT was shown to be an accurate method in the differential diagnosis of benign from malignant solitary pulmonary nodules.

Successful treatment of severe juvenile microscopic polyangiitis with rituximab.

Microscopic polyangiitis (MPA) previously called hypersensitivity angiitis is a systemic necrotizing vasculitis affecting predominantly small vessels. MPA involves multiple organ systems including the lung, the kidneys, the joints, and the skin. MPA mostly affects adults in their fourth and fifth decade of life. MPA and Wegener;s granulomatosis are grouped together as ANCA-associated vasculitis. MPA is associated with high titre of myeloperoxidase antineutrophil cytoplasmic antibodies (MPO)-ANCA. We present a 14-year-old female patient presented with MPA. She was treated with steroids and cyclophosphamide. After the complication of severe lung involvement, rituximab was administered as immune-modulating treatment. The MPA came to remission. This is the first report of a pediatric patient with MPA treated with rituximab. Rituximab might be a potential therapeutic option for relapsing ANCA associated vasculitis in childhood.

An unusual case of intrauterine symptomatic neonatal liver failure.

UNLABELLED: We present an unusual case of neonatal liver failure. Isolated ascites was diagnosed in a female fetus at week 34 gestational age upon routine ultrasound. In the 35th week of gestation a cesarean section was carried out after puncture of fetal ascites. After birth the patient showed symptoms and complications of acute liver failure with portal hypertension. High serum ferritin concentrations, MRI findings compatible with tissue iron overload and no evidence for infectious disease or inborn errors of metabolism suggested possible neonatal hemochromatosis (NH). HFE gene mutation analysis studies of the child and parents were negative. An anti-oxidative and iron chelating therapy was introduced, followed by clinical stabilisation of the newborn and normalisation of liver function. The liver biopsy at 4 month of age showed mild fibrosis with a few iron-loaded hepatocytes and macrophages. At 2 years of age the child was virtually healthy. CONCLUSION: The clinical course of our patient indicates that the pathological changes in the liver being associated with presumptive NH may be reversible when NH is diagnosed early and antioxidative and chelating therapy is immediately initiated.

CD1a down-regulation in primary invasive ductal breast carcinoma may predict regional lymph node invasion and patient outcome.

AIMS: CD1a is a molecule belonging to the highly conserved group of CD1 proteins. Its expression in dendritic cells is related to the presentation of tumour-derived glycolipid antigens to T cells and, consequently, the development of a successful antitumour response. The aim was to investigate the presence of CD1a+ cells in both primary tumours and lymph nodes (LN) of a series of 35 invasive ductal carcinomas by both immunohistochemistry and reverse transcription-polymerase chain reaction. METHODS AND RESULTS: CD1a antigen was more expressed in N0 than N1 breast cancer (P < 0.0001) in both primary lesions and LN metastases and correlated positively and significantly with oestrogen (ER) (P = 0.0025) and progesterone (P = 0.0226) receptor (PR) status, as well as CD4+ and CD8+ T-lymphocyte infiltration. CONCLUSIONS: This is the first report to show a link between CD1a+ mononuclear cells in breast cancer and in paired LN metastases. The positive and significant correlations between the number of CD1a+ cells and positivity of the primary tumour for ER and PR suggest a possible role for CD1a as a prognostic marker for breast cancer, raising the possibility that hormone receptor-positive breast cancer patients may have a better prognosis in the presence of greater dendritic cell infiltration.

Fetal distribution of 5alpha-reductase 1 and 5alpha-reductase 2, and their input on human prostate development.

PURPOSE: Human prostate development starts in the tenth week of gestation. Initial interactions between the epithelium and mesenchyma are stimulated by androgens. The transformation of circulating testosterone to 5alpha-dihydrotestosterone by tissue linked 5alpha-reductase is a key event in androgen metabolism. The 5alpha-dihydrotestosterone mediates androgen effects in the urogenital sinus and external genitalia, leading to the formation of a male phenotype and androgen mediated prostate growth. Supposedly 5alpha-reductase 2 is the predominant isoenzyme in human accessory sex tissue, whereas the function of 5alpha-reductase 1 remains unclear. We focused on the detection, distribution and effects of the 2 isoenzymes during gestation and infancy. MATERIALS AND METHODS: Serial sections from fetuses and infants were immunostained using antibodies directed against 5alpha-reductase 1 and 2. Additionally, to detect the downstream products of androgen synthesis reverse transcriptase-polymerase chain reaction analyses were done for 17 beta-hydroxysteroid dehydrogenase types 2, 3 and 7. RESULTS: Immunohistochemistry revealed positive staining for each isoenzyme throughout fetal development. Moreover, reverse transcriptase-polymerase chain reaction for 5alpha-reductase 1 and 2 confirmed these findings on the transcription level. Additionally, the most relevant enzymatic downstream products of cellular androgen synthesis (17 beta-hydroxysteroid dehydrogenase 2, 3 and 7) were also detected by reverse transcriptase-polymerase chain reaction. CONCLUSIONS: To our knowledge this is the first study revealing the expression and distribution of each 5alpha-reductase isoenzyme as well as the potential contribution of 5alpha-reductase 1 during fetal human prostate development.

Conjoined epigastric heteropagus twins: excision of a parasitic twin from the anterior abdominal wall of her sibling.

Epigastric heteropagus twins (EHT) are an exceedingly rare form of asymmetric conjoined twins in whom the dependent twin (parasite) is attached to the right or left upper abdomen of the dominant part (autosite). Such a case observed at our institution with 34 month follow-up is presented here and the surgical technique described. A magnetic resonance imaging (MRI)-supported surgical separation of the parasite with successful closure of the abdominal wall defect of the autosite was performed. Follow-up studies showed an autosite which was alive and in optimal health. A comprehensive review including data from English and non-English literature is presented.

DMBT1 expression and glycosylation during the adenoma-carcinoma sequence in colorectal cancer.

The gene DMBT1 (deleted in malignant brain tumour-1) has been proposed to play a role in brain and epithelial cancer, but shows unusual features for a classical tumour-suppressor gene. On the one hand, DMBT1 has been linked to mucosal protection, whereas, on the other, it potentially plays a role in epithelial differentiation. Thus its function in a particular tissue is of mechanistic importance for its role in cancer. Because the former function requires secretion to the lumen and the latter function may depend on its presence in the extracellular matrix, we decided to investigate DMBT1 expression, location and its mode of secretion during malignant transformation in colorectal cancer. Using human colorectal PC/AA cell lines and tissue sections from individual patients, we have examined the expression of DMBT1 and its glycosylation in the adenoma-carcinoma sequence leading to the adenocarcinoma phenotype.

Induction chemotherapy to weekly paclitaxel concurrent with curative radiotherapy in stage IV (M0) unresectable head and neck squamous cell carcinoma: a dose escalation study.

The purpose was to determine the maximum tolerated dose (MTD) of weekly paclitaxel with concurrent, daily irradiation in patients with unresectable head and neck squamous cell carcinoma previously submitted to induction chemotherapy. Patients with stage IV, and unresectable tumor and/or node/s were enrolled. Nine male patients were submitted to a course of paclitaxel 175 mg/m2 day 1 and cisplatin 75 mg/m2 day 2 given every 3 weeks for three courses. Curative radiotherapy (RT) started 3 weeks after the last cycle of chemotherapy with the goal of delivering a total dose of 66-70 Gy. During RT weekly paclitaxel was administered for 6 courses if feasible; paclitaxel was given according to a dose escalation schema in cohorts of three patients. Dose level A, 30 mg/m2; dose level B, 40 mg/m2; dose level C, 50 mg/m2. During weekly paclitaxel the major toxicity was mucositis that required a treatment break in two of three patients in dose level C; mucositis grade 4 required interruption of paclitaxel administration in all these patients. RT can be given in a continuous fashion with weekly paclitaxel after induction chemotherapy. The MTD of weekly paclitaxel was 40 mg/m2.

Hepatic failure with neonatal tissue siderosis of hemochromatotic type in an infant presenting with meconium ileus. Case report and differential diagnosis of the perinatal iron storage disorders.

We report on a female preterm infant with hepatic failure and neonatal tissue siderosis of hemochromatotic type diagnosed by using both histochemistry and atomic absorption spectroscopy. The infant presented with meconium ileus, signs of rapidly progressive hepatic failure, and hyperferritinemia (7132 ng/ml). Despite surgery and intensive care the infant died 32 days after birth. Postmortem examination showed a wrinkled liver with extensive collapse of the hepatic architecture and regenerating nodules as well as hepatic and extrahepatic iron accumulation of hemochromatotic type, sparing the reticuloendothelial system. Atomic absorption spectroscopy confirmed an increase in the iron content of various organs: liver, heart, pancreas, oral salivary gland, kidney, and adrenal gland. The increase in the iron content of various organs was determined by comparing the analysis of the propositus with those of 5 gestationally age-related preterm infants who had died in the intensive care unit: 2 died of meconium aspiration syndrome, the other 3 of hyaline membrane disease, bronchopulmonary dysplasia, and immaturity, respectively. We also compared the analysis of 15 fetuses having a a condition predisposing to iron accumulation (trisomy 21, trisomy 18, cytomegalovirus, amnion infection syndrome, Rhesus- and ABO-incompatibility, congenital hemolysis, anti-phospholipid syndrome, congenital heart disease). Delta F508, the most frequent mutation seen in cystic fibrosis patients, was excluded by gene sequencing. Different noxae causing iron accumulation in the neonatal period have led to the statement that neonatal hemochromatosis may collect different etiologies, such as metabolic disorders, infections, chromosomal aberrations, and immunological disorders. In this study, we report the singular evidence of neonatal iron accumulation of hemochromatotic type in an infant presenting with meconium ileus and propose a classification of the neonatal disorders associated with iron accumulation.

Mapping a method for systematically reviewing the medical literature: a helpful checklist postmortem protocol of human immunodeficiency virus (HIV)-related pathology in childhood.

INTRODUCTION: Since the first description of two children affected with human immunodeficiency virus (HIV), various diagnostic procedures have been established. However, the morphologic study of biopsy and autopsy material from children with acquired immunodeficiency syndrome (AIDS) is still of fundamental importance. The morphology has contributed remarkably to the progress in understanding the pathogenesis of the primary tissue lesions and of the sequelae directly or indirectly associated with HIV infection. The aim of this study was to evaluate the HIV pathology in pediatric AIDS (PAIDS) through a systematic review of the English-language literature and to draw up a practical checklist protocol for the postmortem. MATERIALS AND METHODS: Information on HIV pathology in childhood was retrieved from a MEDLINE search (January 1994-January 2001) of the original reports and bibliographic article reviews published in English. Citations from papers retrieved were screened and retrieved papers were evaluated. RESULTS: Based on the screened data, we propose a practical, organ-oriented checklist protocol for the postmortem according to the HIV pathogenesis. CONCLUSIONS: Evidence-based medicine is a paradigm now exerting increasing influence in related fields such as surgery, general practice, psychiatry, and pathology. This article is a summary of the literature on PAIDS pathology. The protocol that we propose is particularly useful for pediatric pathology programs and for electronic data processing.

Accessory liver in an infant with congenital diaphragmatic hernia.

Incidence of congenital diaphragmatic hernia (CDH) ranges from 1 in 2,400 to one in 5,000 live births. Associated anomalies in CDH are approximately 30% to 35%. The authors report on an infant with CDH and an accessory supradiaphragmatic liver with separate vascularization from the thoracic aorta. The pathogenesis of this malformation is discussed. The postoperative course and the follow-up of the child over 5 years was completely uneventful.

Ellis-van Creveld syndrome: a generalized dysplasia of enchondral ossification.

We report a 25-week fetus with lethal Ellis-van Creveld syndrome who was diagnosed prenatally from the US detection of a narrow chest, postaxial polydactyly of the hands, short acro-/mesomelic limbs and a ventricular septal defect. The postnatal radiographic features of the skeleton confirmed the diagnosis. Literature review of the histopathology of the physeal growth plate is contradictory, varying between retardation of the hypertrophic chondrocytes without disorganization and marked disorganization of the proliferating chondrocytes. We investigated numerous sites of the enchondral ossification and observed retardation of the physeal growth plate in all sites and retardation with pronounced disorganization of the physeal growth plate in the upper mesomelic bone segments only. These data support the concept that Ellis-van Creveld syndrome is mainly a generalized disorder of the maturation of enchondral ossification.

Occult thyroid pathology in a child with acquired immunodeficiency syndrome. Case report and review of the drug-related pathology in pediatric acquired immunodeficiency syndrome.

A 11-year-old boy with acquired immunodeficiency syndrome (AaS), Varicella-zoster virus (VZV) infection and long-term antiviral treatment suffered from a disorder of contractility of the left ventricle of the heart. Following severe unmanageable vomiting, the patient died and the postmortem examination showed marked involution of the lymphatic system, multiple foci of fibrosis of both ventricles of the heart, and regressive changes of the thyroid gland. Biochemical values of the thyroid gland function were, however, not altered. Neither human immunodeficiency virus-related p24 antigen, nor VZV DNA sequences were found in the thyroid gland. Regressive changes of the thyroid gland can probably occur before its function fails. By analyzing the possible etiologies, the endocrine toxicity of a long-term antiviral treatment should be taken into account.

Analysis of the spectrum of malformations in human fetuses of the second and third trimester of pregnancy with human triploidy.

Triploidy is constituted by an extra haploid set of chromosomes for a total of 69 chromosomes in humans. A "parent-of-origin" effect has been demonstrated by analysis of cytogenetic polymorphisms of triploidy pregnancies. Two distinct phenotypes of human triploid fetuses have been recognized according to the parental origin of the extra haploid set. The first one or triploidy of diandric type occurs when the extra haploid set of chromosomes arises from the father, the second one or triploidy of digynic type occurs when the extra haploid set of chromosomes arises from the mother. Diandric fetuses appear relatively well grown with a large placenta, while digynic fetuses show intrauterine growth retardation with a small placenta. Autopsy archive data files (1982-1998) of the Institute of Pathology, University of Heidelberg (Germany) were examined for fetuses with triploidy. We found 12 well-studied triploid fetuses (gestational age: 20 to 32 weeks). Eleven fetuses corresponded to the digynic type of triploidy and one fetus corresponded to the diandric type of triploidy. The spectrum of external malformations included a dysmorphic face (broad root of the nose, exophthalmos, low-set ears, micro-/retrognathia, microgenia, median cleft lip and/or palate, gnathoschisis, macroglossia), encephalocele, spina bifida, syndactyly, club or rocker-bottom feet, pes equino-valgus. More common internal malformations included ventricular septum defect of the heart, abnormal lobation of the lungs, and renal disease (agenesis, cysts).

Study of the malformation of ductal plate of the liver in Meckel syndrome and review of other syndromes presenting with this anomaly.

Meckel syndrome (MIM 249.000) is an autosomal recessive disorder with a variable spectrum of anomalies. Since the first reports of this syndrome, very broad diagnostic criteria have been proposed, but the process of defining them continues. It is probable that at least two of three manifestations, including cystic kidney dysplasia, occipital encephalocele or other anomaly of the central nervous system, and postaxial polydactyly occur in most cases. Arrest of the development of intrahepatic bile ducts at the stage of the bilaminar plate formation or ductal plate malformation is considered of high diagnostic value in Meckel syndrome, but there is no complete agreement in the literature about its occurrence. The aims of this investigation were to study the prevalence and morphologic patterns of ductal plate malformation of the liver in Meckel syndrome by evaluating the dilatation of primitive biliary structures and the increase in connective tissue of the portal tract. Archival data files from four German centers (Berlin, Freiburg, Heidelberg, Mainz) were reviewed. Liver sections of 30 well-studied fetuses with Meckel syndrome were immunostained with antibodies against cytokeratins (intermediate filaments of the cytoskeleton) and factor VIII (an endothelial cell marker) and were evaluated both qualitatively and quantitatively. Cystic kidney dysplasia, occipital encephalocele, and postaxial polydactyly were found in 100%, 90%, and 83.3% of the fetuses, respectively. Ductal plate malformation of the liver was a constant anomaly in Meckel syndrome, seen as frequently as renal lesions. We observed essentially two kinds of hepatic lesions: 23 cases showed mainly a cystic dilatation of primitive biliary structures with little portal fibrosis, while 7 cases showed mainly rings of interrupted curved lumina around a central fibrovascular axis and pronounced portal fibrosis. In these seven cases an abnormal pattern of the portal vein, with many small and closely spaced branches of the portal vein (the so-called pollard willow pattern), was also seen. With respect to other fetal developmental anomalies, no difference between the two types of lesions was found. We also provide a potentially useful comprehensive review of other genetic syndromes in which ductal plate malformations may occur.

Contribution of apoptosis and apoptosis-related proteins to the malformation of the primitive intrahepatic biliary system in Meckel syndrome.

In the developing liver, the complete or partial persistence of the primitive double-layered cylinder of biliary-type cells that surrounds the branches of portal vein and its mesenchyme gives origin to portal tracts with an increased number of bile duct structures. The term "ductal plate malformation of the liver" was coined to label the insufficient remodeling of the primitive intrahepatic biliary system. Meckel syndrome is an autosomal recessive inherited disease characterized by occipital encephalocele, postaxial polydactyly, diffuse cystic renal dysplasia, and malformation of the ductal plate of the liver. We studied 52 fetuses with Meckel syndrome from five German centers (Berlin, Freiburg, Heidelberg, Mainz, and Marburg). Analysis of apoptosis and cell proliferation (Ki-67) was performed by terminal deoxynucleotide transferase-mediated dUTP nick-end labeling (TUNEL) and immunohistochemistry in the liver of 24 normal fetuses of different gestational ages (14-38 weeks of gestation) and in 14 fetuses with Meckel syndrome (17-38 weeks of gestation). The expression of two apoptosis-related proteins, Fas (a transmembrane cell surface protein involved in the apoptosis) and Bcl-2 (an anti-apoptotic protein), was studied by immunohistochemistry in the liver of 11 normal fetuses of different gestational ages (14-40 weeks of gestation) and in 40 fetuses with Meckel syndrome (16-38 weeks of gestation). In control fetuses, apoptosis rate and cell proliferation were high in the remodeling ductal plate and moderate in the ductal plate and in remodeled bile ducts. During gestation, expression of Fas and Bcl-2 decreased and increased, respectively. The malformed ductal plates in the fetal livers with Meckel syndrome showed a marked decrease in the apoptotic rate and Fas expression and an increase in proliferative activity and Bcl-2 expression in comparison with control fetuses. Furthermore, by linear regression analysis, we found that both proliferation activity and apoptosis rate in the ductal plate malformation of fetuses with Meckel syndrome were practically constant along the gestation. These results, which represent the first systematic study of apoptosis in ductal plate malformation of the liver, indicate that 1) animals harboring the gene defect of Meckel syndrome could be a good model for the study of the abnormal development of the primitive intrahepatic biliary system, 2) a decreased cell turnover occurs in the ductal plate malformation of fetuses with Meckel syndrome, and 3) the increase of Bcl-2 expression contributes to the pathogenesis of the lack of remodeling of ductal plate of the liver in Meckel syndrome.