Role of Waddlia chondrophila placental infection in miscarriage

Waddlia chondrophila is an intracellular bacterium suspected to cause human and bovine abortion. We confirmed an association between antibodies against W. chondrophila and human miscarriage and identified this organism in placenta or genital tract of women who had had miscarriages. These results suggest a possible role of W. chondrophila infection in miscarriage.

The channel-activating protease CAP1/Prss8 is required for placental labyrinth maturation

The serine protease CAP1/Prss8 is crucial for skin barrier function, lung alveolar fluid clearance and has been unveiled as diagnostic marker for specific cancer types. Here, we show that a constitutive knockout of CAP1/Prss8 leads to embryonic lethality. These embryos presented no specific defects, but it is during this period, and in particular at E13.5, that wildtype placentas show an increased expression of CAP1/Prss8, thus suggesting a placental defect in the knockout situation. The placentas of knockout embryos exhibited significantly reduced vascular development and incomplete cellular maturation. In contrary, epiblast-specific deletion of CAP1/Prss8 allowed development until birth. These CAP1/Prss8-deficient newborns presented abnormal epidermis, and died soon after birth due to impaired skin function. We thus conclude that a late placental insufficiency might be the primary cause of embryonic lethality in CAP1/Prss8 knockouts. This study highlights a novel and crucial role for CAP1/Prss8 in placental development and function.

Intestinal spirochetosis mimicking inflammatory bowel disease in children

Background

Intestinal spirochetosis is an unusual infection in children and its clinical significance in humans is uncertain. The presence of these microorganisms in humans is well-known since the late 1800’s and was first described in 1967 by Harland and Lee by electron microscopy.

Case presentation

This article reports the findings of one pediatric case, review of the current literature, and an overview of therapeutic options.

Conclusion

A high degree of suspicion is required in cases presenting with abdominal pain, chronic diarrhoea and/or hematochezia associated with a normal endoscopic examination, thus emphasizing the importance of multiple biopsies throughout the colon.

Prenatal diagnosis of congenital lung malformations

Prenatal diagnosis of congenital lung anomalies has increased in recent years as imaging methods have benefitted from technical improvements. The purpose of this pictorial essay is to illustrate typical imaging findings of a wide spectrum of congenital lung anomalies on prenatal US and MRI. Moreover, we propose an algorithm based on imaging findings to facilitate the differential diagnosis, and suggest a follow-up algorithm during pregnancy and in the immediate postnatal period.

Role of Chlamydia trachomatis in miscarriage

To determine the role of Chlamydia trachomatis in miscarriage, we prospectively collected serum, cervicovaginal swab specimens, and placental samples from 386 women with and without miscarriage. Prevalence of immunoglobulin G against C. trachomatis was higher in the miscarriage group than in the control group (15.2% vs. 7.3%; p = 0.018). Association between C. trachomatis-positive serologic results and miscarriage remained significant after adjustment for age, origin, education, and number of sex partners (odds ratio 2.3, 95% confidence interval 1.1-4.9). C. trachomatis DNA was more frequently amplified from products of conception or placenta from women who had a miscarriage (4%) than from controls (0.7%; p = 0.026). Immunohistochemical analysis confirmed C. trachomatis in placenta from 5 of 7 patients with positive PCR results, whereas results of immunohistochemical analysis were negative in placenta samples from all 8 negative controls tested. Associations between miscarriage and serologic/molecular evidence of C. trachomatis infection support its role in miscarriage.

Phenotypic and molecular characterization of a novel case of dyssegmental dysplasia, Silverman-Handmaker type

Dyssegmental dysplasia, Silverman-Handmaker type (DDSH; #MIM 224410) is an autosomal recessive form of lethal dwarfism characterized by a defect in segmentation and fusion of vertebral bodies components ("anisospondyly") and by severe limb shortening. It is caused by mutations in the perlecan gene (HSPG2), but so far, only three molecularly confirmed cases have been reported. We report a novel case of DDSH in a fetus that presented at 15 weeks gestation with encephalocele, severe micromelic dwarfism and narrow thorax. After termination of pregnancy, radiographs showed short ribs, short and bent long bones and anisospondyly of two vertebral bodies. The fetus was homozygous for a previously undescribed null mutation in HSPG2.

Solid pseudopapillary tumor of the pancreas in children: typical radiological findings and pathological correlation

We report a case series of three children with solid pseudopapillary tumor of the pancreas (SPT) in which a complete radiological work-up, including ultrasound, computed tomography scans, and MRI, has been carried out. The aim of this article is to highlight the characteristic imaging findings of SPT in the pediatric age group and to establish a correlation with typical histopathological findings of the lesion.

Placental vascular obstructive lesions: risk factor for developing necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a severe neonatal disease affecting particularly preterm infants. Its exact pathogenesis still remains unknown. In this study, we have compared the prevalence of vascular obstructive lesions in placentae of premature newborns which developed NEC and of a control group. We further compared separately the findings of placentae of infants of less than 30 weeks of gestation, the age group in which NEC occurs most frequently. We found signs of fetal vascular obstructive lesions in 65% of the placentae of preterm patients developing NEC, compared to only 17% of the placentae of preterm patients in the control group. In the age groups below 30 weeks of gestation, 58.5% of placentae of later NEC patients presented such lesions compared to 24.5% in the control group. The significant difference between NEC and control group suggests a strong association between fetal vascular obstructive lesions and NEC. Therefore, we propose that fetal vascular obstructive lesions might be considered as a risk factor for the development of NEC in premature infants.

Familial occurrence of an association of multiple intestinal atresia and choanal atresia: a new syndrome?

We report on two familial cases from a non-consanguineous marriage, presenting multiple intestinal and choanal atresia. Massive hydramnios and dilatation of the bowel were observed at 29 weeks of gestation during routine ultrasound scan of a healthy mother. The fetal karyotype was normal and cystic fibrosis screening was negative. Regular scans were performed throughout the pregnancy. The child was born at 34 weeks gestation. Choanal atresia was diagnosed at birth and abdominal investigations showed multiple atresia interesting both the small bowel and the colon. Further interventions were necessary because of recurrent obstructions. During the following pregnancy, a dilatation of the fetal intestinal tract was detected by ultrasonography at 27 weeks of gestation. Pregnancy was interrupted. Post-mortem examination of the fetus confirmed the stenosis of long segments of the small intestine associated with areas of colonic atresia. In both cases, histology and distribution were consistent with those reported in hereditary multiple intestinal atresia (HMIA). An association between multiple intestinal and choanal atresia has never been reported. We suggest it could correspond to a new autosomal recessive entity for which cytogenetic investigations and high-resolution array CGH revealed no visible anomalies.

Hirschsprung's disease: the "Swiss roll" technique revisited

PURPOSE

During pull-through for Hirschsprung's disease (HSCR), the assessment of innervation is mainly based on the presence of ganglion cells when conventional Hematoxylin and Eosin (HE) staining is used. In hypoganglionosis, the evaluation is difficult. We adapted a standardized methodology for the examination of resected bowel after HSCR surgery, using the technique described by Moolenbeek on rodent intestine and later by Meier-Ruge in children. We have analysed the entire innervation of surgically resected bowels and compared the results with the follow up of patients.

METHODS

Three longitudinal strips of colon were harvested from the mesenteric, anti-mesenteric and intermediate part in the whole length of resected colon of six patients with HSCR. Each strip was divided into two parts. One of the contiguous strips was assessed with HE and Hematoxylin-Phloxin-Safran, and the other one with acetylcholinesterase (AChE) histochemistry. We analyzed the distribution of ganglion cells and nerve arrangement along the strips with both techniques and compared the results obtained in the three different regions of the bowel.

RESULTS

There was no significant difference in the pattern of innervation circumferentially. There was a correlation between a progressive increase of AChE activity and nerve hypertrophy and a decrease of ganglion cells from the proximal to the distal part of the resected colon in the submucosa and the myenteric plexus. Nerve hypertrophy and AChE-positive reaction in the mucosa were found at the resection border in patients who presented postoperative complications.

CONCLUSIONS

Simultaneous assessment of nerve cells, nerve fibers and AChE activity is important in the evaluation of the innervation of the bowel segment proximal to the aganglionic zone. The method described is feasible and can be adapted to older children and adults with larger bowels. These results point out the importance of assessing nerve fibers in intraoperative biopsies during pull-through procedures to prevent uncomplete surgical bowel resection.

Gastric outlet obstruction by Brunner's gland hyperplasia in an 8-year-old child

Several cases of Brunner's gland hyperplasia causing hemorrhage, obstruction, or intussusception have been published in the adult literature. Similar cases in the pediatric population are very rare and have only been described twice, always associated with chronic renal failure. We report the third and youngest case of gastric outlet obstruction because of Brunner's gland hyperplasia focusing on histopathologic condition and treatment based on a review of the literature.

Identification of cancer stem cells in Ewing's sarcoma

Cancer stem cells that display tumor-initiating properties have recently been identified in several distinct types of malignancies, holding promise for more effective therapeutic strategies. However, evidence of such cells in sarcomas, which include some of the most aggressive and therapy-resistant tumors, has not been shown to date. Here, we identify and characterize cancer stem cells in Ewing's sarcoma family tumors (ESFT), a highly aggressive pediatric malignancy believed to be of mesenchymal stem cell (MSC) origin. Using magnetic bead cell separation of primary ESFT, we have isolated a subpopulation of CD133+ tumor cells that display the capacity to initiate and sustain tumor growth through serial transplantation in nonobese diabetic/severe combined immunodeficiency mice, re-establishing at each in vivo passage the parental tumor phenotype and hierarchical cell organization. Consistent with the plasticity of MSCs, in vitro differentiation assays showed that the CD133+ cell population retained the ability to differentiate along adipogenic, osteogenic, and chondrogenic lineages. Quantitative real-time PCR analysis of genes implicated in stem cell maintenance revealed that CD133+ ESFT cells express significantly higher levels of OCT4 and NANOG than their CD133- counterparts. Taken together, our observations provide the first identification of ESFT cancer stem cells and demonstration of their MSC properties, a critical step towards a better biological understanding and rational therapeutic targeting of these tumors.

Identification of cancer stem cells in Ewing's sarcoma

Cancer stem cells that display tumor-initiating properties have recently been identified in several distinct types of malignancies, holding promise for more effective therapeutic strategies. However, evidence of such cells in sarcomas, which include some of the most aggressive and therapy-resistant tumors, has not been shown to date. Here, we identify and characterize cancer stem cells in Ewing's sarcoma family tumors (ESFT), a highly aggressive pediatric malignancy believed to be of mesenchymal stem cell (MSC) origin. Using magnetic bead cell separation of primary ESFT, we have isolated a subpopulation of CD133+ tumor cells that display the capacity to initiate and sustain tumor growth through serial transplantation in nonobese diabetic/severe combined immunodeficiency mice, re-establishing at each in vivo passage the parental tumor phenotype and hierarchical cell organization. Consistent with the plasticity of MSCs, in vitro differentiation assays showed that the CD133+ cell population retained the ability to differentiate along adipogenic, osteogenic, and chondrogenic lineages. Quantitative real-time PCR analysis of genes implicated in stem cell maintenance revealed that CD133+ ESFT cells express significantly higher levels of OCT4 and NANOG than their CD133- counterparts. Taken together, our observations provide the first identification of ESFT cancer stem cells and demonstration of their MSC properties, a critical step towards a better biological understanding and rational therapeutic targeting of these tumors.

Imprinting of tumor-suppressor genes in human placenta

Transcriptional deregulation in cancer has been shown to be associated with epigenetic alterations, in particular to tumor-suppressor- gene (TSG) promoters. In contrast, DNA methylation of TSGs is not considered to be present in normal differentiated cells. Nevertheless, we previously showed that the promoter of the tumor-suppressor gene APC is methylated, for one allele only, in normal gastric cells. Recently, RASSF1A has been shown to be imprinted in normal human placenta. To clarify putative TSG methylation in the placenta, 23 normal placental tissues from the first trimester, both decidua and villi, and four normal non-gestational endometrium were screened for DNA methylation by methylation-sensitive single-strand conformation analysis (MS-SSCA) and sequencing after bisulfite modification, on a panel of 12 genes known to be implicated in carcinogenesis. In all placental villi, four TSG promoters-APC, SFRP2, RASSF1A and WIF1-were hypermethylated, whereas all decidua and normal endometrium did not show any methylation. Allele-specific methylation analysis revealed that this methylation was monoallelic. Furthermore, comparison with maternal DNA indicated that APC and WIF1 were methylated on the maternal allele, whereas SFRP2 was methylated on the paternal allele. Sequence analysis of WIF1 mRNA revealed that only the unmethylated paternal allele was transcribed. The imprinting status of these TSGs is conserved during pregnancy. These results indicate that TSG imprinting is pre-existent in normal human placenta and should not be confused with carcinogenesis or pathology-induced methylation.

Isolation and in vitro chondrogenic potential of human foetal spine cells

Cell therapy for nucleus pulposus (NP) regeneration is an attractive treatment for early disc degeneration as shown by studies using autologous NP cells or stem cells. Another potential source of cells is foetal cells. We investigated the feasibility of isolating foetal cells from human foetal spine tissues and assessed their chondrogenic potential in alginate bead cultures. Histology and immunohistochemistry of foetal tissues showed that the structure and the matrix composition (aggrecan, type I and II collagen) of foetal intervertebral disc (IVD) were similar to adult IVD. Isolated foetal cells were cultured in monolayer in basic media supplemented with 10% Fetal Bovine Serum (FBS) and from each foetal tissue donation, a cell bank of foetal spine cells at passage 2 was established and was composed of around 2000 vials of 5 million cells. Gene expression and immunohistochemistry of foetal spine cells cultured in alginate beads during 28 days showed that cells were able to produce aggrecan and type II collagen and very low level of type I and type X collagen, indicating chondrogenic differentiation. However variability in matrix synthesis was observed between donors. In conclusion, foetal cells could be isolated from human foetal spine tissues and since these cells showed chondrogenic potential, they could be a potential cell source for IVD regeneration.

Molecular risk stratification of medulloblastoma patients based on immunohistochemical analysis of MYC, LDHB, and CCNB1 expression

PURPOSE

Medulloblastoma is the most common malignant embryonal brain tumor in children. The current clinical risk stratification to select treatment modalities is not optimal because it does not identify the standard-risk patients with resistant disease or the unknown number of high-risk patients who might be overtreated with current protocols. The aim of this study is to improve the risk stratification of medulloblastoma patients by using the expression of multiple prognostic markers in combination with current clinical parameters.

EXPERIMENTAL DESIGN

Candidate prognostic markers were selected from literature or from medulloblastoma expression data. Selected genes were immunohistochemically analyzed for their prognostic value using medulloblastoma tissue arrays containing 124 well-characterized patient samples.

RESULTS

Protein expression analyses showed that the combined expression of three genes was able to predict survival in medulloblastoma patients. Low MYC expression identified medulloblastoma patients with a very good outcome. In contrast, concomitant expression of LDHB and CCNB1 characterized patients with a very poor outcome. Multivariate analyses showed that both expression of MYC and the LDHB/CCNB1 gene signature were strong prognostic markers independent of the clinical parameters metastasis and residual disease. Combined analysis of clinical and molecular markers enabled greater resolution of disease risk than clinical factors alone.

CONCLUSIONS

A molecular risk stratification model for medulloblastoma patients is proposed based on the signature of MYC, LDHB, and CCNB1 expression. Combined with clinical variables, the model may provide a more accurate basis for targeting therapy in children with this disease.

A 16-month-old boy vomits a double tongue: intraluminal duplication of the cervical esophagus in children

A 16-month-old boy presented with a story of stridor, solid dysphagia and a history of spectacular protrusion underneath his tongue which was mistaken by the parents for a snake's tongue! The radiological examinations showed a filling defect of the upper and middle third esophagus which compressed the cervical trachea. This was found to be an intraluminal tubular esophageal duplication. Treatment by cervicotomy and unusual histological facts are presented.

Combination of immunohistochemistry and ploidy analysis to assist histopathological diagnosis of molar diseases

Background:

Differential diagnosis between hydropic abortion, partial mole and complete mole is still a challenge for pathologists but really important for patient management.

Material and Method:

In this study, we have evaluated 111 products of conception from the first trimester. Histological analysis was made according to the main diagnostic histopathological features described in the literature and the cases were categorized in hydropic abortus (HA), partial mole (PM) and complete mole (CM). Immunohistochemistry was performed using monoclonal antibody against p57^kip protein a putative paternally imprinted inhibitor gene and DNA ploidy was analysed in all cases by image cytometry.

Results:

All 23 HAs presented a diploid DNA content and were p57^kip2 positive. From the 28 CMs, 12 cases (43%) were diploid and 16 cases (57%) were tetraploid but no expression of p57^kip2 was found with positive internal controls. From the 60 PMs, 58 cases were positive for p57^kip2 expression and 53 cases (88%) were triploid, 6 cases (10%) tetraploid and 1 case (2%) diploid.

Conclusion:

This study on 111 cases of early pregnancies confirms the usefulness of immunohistochemistry and cytometry but demonstrates the importance of the combination of both techniques to assist histology for the best reliable diagnosis.

Role of DNA content analysis and immunohistochemistry in the evaluation of the risk of unfavourable outcome in Wilms' tumours

BACKGROUND

Wilms' tumour (WT) is the most common solid tumour affecting young children. Its histological diversity leads to difficulties in predicting the outcome.

MATERIALS AND METHODS

Image analysis cytometry and immunohistochemistry with a selected panel of antibodies were performed in 23 cases of WT considered of intermediate risk according to the revised International Society of Pediatric Oncology (SIOP) working classification of renal tumours of childhood. In this series, a tumour was considered aggressive according to its propensity for metastases or its recurrence.

RESULTS

Out of the 14 non-aggressive WT, 4 were found to be diploid and 10 were aneuploid including 6 that were heterogeneous for DNA-ploidy. All the tumours presented a low proliferative index and were negative for p53 and p57(kip2) immunostaining. Out of the 9 aggressive tumours, all were aneuploid and 4 were found to be heterogeneous for DNA-ploidy. They all presented a high degree of cell proliferation and 7 were positive for p53 immunostaining. Only two were positive for the p57(kip2) marker. The only fatal case revealed an aneuploid-homogeneous DNA-ploidy analysis, was p53 and p57(kip2) positive and presented a high cell proliferation index.

CONCLUSION

A significant correlation between the presence of focal DNA-aneuploidy in Wilms' tumours and adverse prognosis is not established, but some immunohistochemical markers may be useful for the clinical evaluation of these tumours and to help in predicting the risk of an unfavourable outcome.

[Pediatric pathology: a child is not an adult in miniature form]

In pediatric pathology, diagnosis explores major aspects of childhood disorders ranging from malformative syndromes to neoplasm's and forensic pathology. For this mental gymnastics, knowledge of the different morphological and physiological process of development and adaptation are essential. Furthermore, new adjuvant technology ensure a more precise diagnosis by the pediatric pathologist. A review of some particular situations in child are illustrated below.

Digital image DNA cytometry: a useful tool for the evaluation of malignancy in biliary strictures

Background: Cytologic evaluation of the biliary tract strictures is nowadays widely used for distinguishing between benign and malignant lesions but remains a challenge for some problematic cases. Digital Image cytometry (DNA-cytometry) helps cytopathologists to resolve some unclear situations.

Methods: We have analysed 41 specimens of bile duct brushings obtained from patients during ERCP (11 benign cases, 7 suspicious for malignancy cases and 23 malignant cases) by DNA-cytometry and correlated them with the histological biopsy counterpart.

Results: All eleven cytological and histological benign cases were DNA-diploid and among 22 patients with malignant cytological and histological diagnosis 21 were DNA-aneuploid. One case considered malignant by the cytopathologist revealed DNA-aneuploid but malignancy could not be confirmed by histology. The analysis of the suspicious for malignancy cases revealed that all DNA-aneuploid cases were malignant and all DNA-diploid cases were benign referring to the follow-up of the patients.

The comparison between cytology alone and cytology combined with DNA-cytometry related to the histological diagnosis (gold standard) resulted in a sensitivity of 100% and a specificity of 79% for cytology alone; a specificity of 94% and a sensitivity 92% for DNA-cytometry and a specificity of 93% and a sensitivity of 100% with combined analyses. The positive predictive value was 90% for cytology, 96% for DNA-cytometry and for both analyses. The negative predictive value showed 100% for cytology, 89% for DNA-cytometry and 100% for combined studies.

Conclusions: Despite the limited number of patients involved in the study, the Results obtained indicate an increased of specificity and of positive predictive value using DNA-cytometry. These Results confirm the pertinence of these method for challenging cases, in conjunction with other available diagnostic tools.

Deoxyribonucleic acid content as an indicator of progression of squamous cell carcinogenesis in the esophagus: Comparative analysis on imprint-cytospin and tissue section preparation

BACKGROUND

The purpose of this study was to explore the potential use of image analysis on tissue sections preparation as a predictive marker of early malignant changes during squamous cell (SC) carcinogenesis in the esophagus. Results of DNA ploidy quantification on formalin-fixed, paraffin-embedded tissue using two different techniques were compared: imprint-cytospin and 6 microm thick tissue sections preparation.

METHODS

This retrospective study included 26 surgical specimens of squamous cell carcinoma (SCC) from patients who underwent surgery alone at the Department of Surgery in CHUV Hospital in Lausanne between January 1993 and December 2000. We analyzed 53 samples of healthy tissue, 43 tumors and 7 lymph node metastases.

RESULTS

Diploid DNA histogram patterns were observed in all histologically healthy tissues, either distant or proximal to the lesion. Aneuploidy was observed in 34 (79%) of 43 carcinomas, namely 24 (75%) of 32 early squamous cell carcinomas and 10 (91%) of 11 advanced carcinomas. DNA content was similar in the different tumor stages, whether patients presented with single or multiple synchronous tumors. All lymph node metastases had similar DNA content as their primary tumor.

CONCLUSIONS

Early malignant changes in the esophagus are associated with alteration in DNA content, and aneuploidy tends to correlate with progression of invasive SCC. A very good correlation between imprint-cytospin and tissue section analysis was observed. Although each method used here showed advantages and disadvantages; tissue sections preparation provided useful information on aberrant cell-cycle regulation and helped select the optimal treatment for the individual patient along with consideration of other clinical parameters.

Image cytometry: an aid for cytological diagnosis of pleural effusions

The conventional cytology rate for identification of neoplastic cells in effusions is about 60%. The rate of diagnostically equivocal effusions in routine cytology is dependent on the volume of effusion examined, type of preparation and staining, experience of the examiner, and application of ancillary methods. The aim of our study was to confirm the role of image cytometry analysis (DNA-ploidy) on pleural effusions. In this retrospective study based on 42 available cases with a histological diagnosis, we have examined 13 reactive mesothelial proliferations and 29 cases of malignant tumors (adenocarcinoma [ACA] or mesothelioma). The smears collected were submitted to the image analysis following a-three step protocol (smears stained with the Papanicolaou method were destained and then restained with Feulgen staining and finally analysed using image analysis cytometry). The results have shown that nonmalignant cases (reactive mesothelial proliferation) were all diploid and in contrast all aneuploid cases corresponded to malignant tumors. Only three mesotheliomas showed a diploid profile. In conclusion, these results confirm data from literature and indicate that cytometric analysis of nuclear content is a useful marker for identification of malignant cells in equivocal effusions and can be used to increase the cytological sensitivity in doubtful mesothelial proliferations.

DNA-ploidy in advanced gastric carcinoma is less heterogeneous than in early gastric cancer

This analysis of DNA‐ploidy heterogeneity in advanced gastric carcinomas is consistent with the hypothesis of the emergence of a single aneuploid cell clone as a crucial mechanism in the progression from early gastric carcinoma to advanced gastric cancer. The prognostic value of DNA‐ploidy in gastric cancers has been a matter of controversy. Tumour DNA‐ploidy heterogeneity, the presence within the same tumour of multiple stemlines differing in DNA content, has been described in various tumours including gastric cancers. The occurrence of such heterogeneity has been accepted as an explanation for the divergent DNA‐ploidy results in this type of tumours. A previous study of early gastric cancers suggested that in pure diploid superficial carcinomas, genetic instability might lead to a cell clone which has undergone a ploidy shift and is more aggressive. If so, this would initially result in DNA‐ploidy heterogeneity. Proliferative dominance of the aneuploid clone could eventually evolve to a homogeneous aneuploid tumour. In order to test this hypothesis, we studied DNA‐aneuploidy and DNA‐ploidy heterogeneity in advanced gastric carcinomas. We performed DNA cytophotometry on multiple samples collected from 16 advanced gastric carcinomas and found 15 DNA‐aneuploid tumours (94%) and one diploid tumour. Multiple DNA‐stemlines were found in 4 cases (26%). Analysis of proliferative activity performed on the same samples revealed higher proliferation rate in DNA‐ploidy homogeneous tumours than in aneuploid heterogeneous tumours. Heterogeneous tumours did not overexpress p53. These results confirm that DNA‐aneuploidy is frequent in advanced gastric cancer and demonstrate that a majority of these aneuploid tumours are not DNA‐ploidy heterogeneous. Furthermore, the higher proliferative activity in homogeneous‐aneuploid carcinomas and their more frequent overexpression of p53 support the hypothesis that in gastric cancer tumour progression implies the development of a dominant and more aggressive (higher proliferative activity, p53 overexpression) aneuploid cell clone.

p16 inactivation by methylation of the CDKN2A promoter occurs early during neoplastic progression in Barrett's esophagus

BACKGROUND & AIMS

The potential role of p16 inactivation by CDKN2A/p16 promoter hypermethylation and/or loss of heterozygosity (LOH) of the CDKN2A gene was investigated in neoplastic progression of Barrett's esophagus.

METHODS

CDKN2A promoter hypermethylation was studied by methylation sensitive single-strand conformation analysis and sequencing using bisulfite modified DNA in Barrett's esophageal adenocarcinomas, premalignant lesions, and normal squamous esophageal epithelium. All of the lesions of interest were sampled by microdissection from paraffin-embedded fixed tissue sections.

RESULTS

No methylation of the CDKN2A promoter was found in normal esophageal squamous cell epithelia, whereas methylation was detected in 18 of 22 (82%) adenocarcinomas and 10 of 33 (30%) premalignant lesions, including 4 of 12 (33%) samples with intestinal metaplasia only. LOH at the CDKN2A gene locus was found in 68% of adenocarcinomas and in 55% of premalignant lesions. Of 28 samples without p16 immunoreactivity, 25 (89%) showed CDKN2A promoter hypermethylation with or without LOH of CDKN2A. Only 2 (8%) samples expressing p16 protein were found to be methylated; these showed a mixture of completely methylated and unmethylated CDKN2A promoters. In 7 of 19 (37%) informative samples without LOH of CDKN2A, the CDKN2A promoter was found to be methylated at both alleles. Loss of p16 protein expression was strongly associated with CDKN2A promoter hypermethylation (P < 0.00001), but not with LOH (P = 0.33).

CONCLUSIONS

Our results indicate that methylation of the CDKN2A promoter is the predominant mechanism for p16 inactivation. This hypermethylation is a very common event in esophageal adenocarcinoma and occurs as early as metaplasia.

Beta-catenin expression and its association with prognostic factors in adenocarcinoma developed in Barrett esophagus

The majority of the adenocarcinomas arising in Barrett esophagus manifest clinically at an advanced stage and have a poor prognosis. As a result of this poor prognosis, much attention has been directed toward the exploration of markers for neoplastic progression in Barrett esophagus. The objective of the present study was to determine the expression of beta-catenin by immunohistochemical analysis in 70 adenocarcinomas developed in Barrett esophagus and to examine its relationship to various prognostic factors currently in use. Abnormal beta-catenin expression, consisting of the loss of membranous staining and the appearance of the nuclear staining, was found in 43 cases (61%). Of patients with the 43 tumors showing abnormal beta-catenin expression, 25 (58%) survived more than 1 year. In contrast, only 7 (26%) of 27 patients with tumors showing normal beta-catenin expression survived longer than 1 year. Most of the superficial (Tis-T1) tumors (83% [10/12]) exhibited abnormal beta-catenin expression compared with only 53% (31/58) in the T2-T3 group. These results suggest a possible correlation among beta-catenin expression, tumor stage, and length of survival as prognostic factors in patients with adenocarcinoma in Barrett esophagus.

Primary neuroendocrine carcinoma of the liver: an autopsy case

An autopsy case of primary hepatic neuroendocrine carcinoma is described. A 72-year-old man had a large tumor mass measuring 22 cm in its greatest diameter and localized to the right, left and caudal lobes of the non-cirrhotic liver. Microscopically, the tumor was composed of middle-sized pleomorphic cells organized in ribbons or trabeculae, with scanty intersecting fibrous septae. Immunohistochemically, the tumor cells were positive for multikeratin C11, chromogranin A and synaptophysin. The patient also had metastases in the bone marrow. No alternative primary source of endocrine tumor was detected. The patient died 4 days after presentation.

p53 gene mutation and protein accumulation during neoplastic progression in Barrett's esophagus

The aim of the present study was to characterize expression and mutation of p53 during the neoplastic progression from Barrett's esophagus to adenocarcinoma and to test the reliability of immunohistochemistry for p53 overexpression as an indicator of p53 mutation in this context. The association of both gene mutation and protein accumulation with clinicopathological findings and survival was also studied. A total of 77 samples from 30 esophagectomy specimens with Barrett's esophagus and adenocarcinoma of patients in longitudinal clinical follow-up were analyzed. Different lesions (intestinal metaplasia, dysplasia, and adenocarcinoma) as well as normal squamous-cell esophageal epithelia were sampled from formalin-fixed, paraffin-embedded tissues by microdissection. Mutations in p53 Exons 5 to 9 were detected by polymerase chain reaction-single-strand conformation polymorphisms (PCR-SSCP) and confirmed by direct DNA sequencing. Nuclear accumulation of p53 protein was analyzed immunohistochemically from tissue sections adjacent to those used for microdissection. p53 gene mutations were found in 17 and p53 protein accumulation were found in 20 tumor samples. Of the 17 adenocarcinomas with a p53 mutation, 16 stained positive for p53 protein. p53 mutations were detected significantly more frequently in high-grade dysplastic than in low-grade dysplastic lesions (77% versus 29%, P < 0.01). In contrast, nuclear accumulation of p53 was detected in 85% of high-grade and 71% of low-grade dysplastic lesions. In eight cases with p53 mutation, the mutation identified in the tumors was also detected in premalignant lesions, mainly in high-grade dysplasia. In four cases of p53-mutated tumors, clones with different p53 mutations were detected in premalignant lesions. Neither p53 mutations nor p53 protein accumulations were found in metaplastic lesions. In summary, we found that p53 mutations occurred mainly during the transition from low-grade to high-grade dysplasia in the neoplastic progression of Barrett's esophagus but not in the nondysplastic Barrett's mucosa. Mutational analysis of p53 by PCR-SSCP and p53 accumulation by immunohistochemistry were mostly concordant in adenocarcinoma and high-grade dysplastic lesions but frequently discordant in low-grade dysplastic lesions. No correlation between p53 gene mutation or p53 accumulation and clinicopathological findings was observed in this study.

Promoter methylation analysis on microdissected paraffin-embedded tissues using bisulfite treatment and PCR-SSCP

Methylation-sensitive single-strand conformation analysis (MS-SSCA) is a new method of screening for DNA methylation changes. The combination of bisulfite modification and PCR results in the conversion of unmethylated cytosines to thymines, whereas methylated cytosines remain unchanged. This sequence conversion can lead to methylation-dependent alterations of single-strand conformation, which can be detected by SSCA. An analysis of mixtures of methylated and unmethylated DNA at known ratios revealed that the relative intensities of the corresponding bands following MS-SSCA were maintained. MS-SSCA was applied for methylation analysis of human p16 promoter region using genomic DNA obtained from either frozen, fixed, or microdissected fixed tissue sections. MS-SSCA is a rapid, specific, and semiquantitative approach that allows the detection of methylation of the p16 gene promoter. In reconstruction experiments, the method permits the detection of 10% or less of cells harboring a methylated p16 promoter. We have been successful in analyzing by MS-SSCA almost all (96%) tumor samples microdissected from archival paraffin-embedded fixed tissue sections and obtaining reproducible results. In addition, when microdissection was performed, the clonality of this genetic alteration could be identified.

Nuclear accumulation of beta-catenin is a common and early event during neoplastic progression of Barrett esophagus

Our aim was to characterize expression and mutation of beta-catenin in the progression of Barrett esophagus to adenocarcinoma. Immunohistochemical analysis of beta-catenin was performed on paraffin-embedded tissue from 30 cases with adenocarcinomas and premalignant lesions. To determine whether there is a correlation between beta-catenin nuclear accumulation and exon 3 mutation of this gene, mutational analysis by polymerase chain reaction-single-strand conformation polymorphism was performed on DNA extracted from the same 30 adenocarcinomas. As a result, the prevalence of reduced expression of beta-catenin on the membrane, with or without nuclear staining, increased significantly from low-grade (LG) to high-grade (HG) dysplasia. Focal nuclear staining for beta-catenin was present in 19 cases of adenocarcinoma, and nuclear staining was associated significantly with progression from metaplasia to LG dysplasia. In addition, in glands with clear histologic transition from metaplasia to LG dysplasia, nuclear accumulation of beta-catenin was found only in the LG dysplastic areas. No mutation in exon 3 of the beta-catenin gene was detected in adenocarcinomas. These results demonstrate that disturbance of the APC/beta-catenin pathway, as indicated by nuclear accumulation of beta-catenin, is a common and early event during neoplastic progression in Barrett esophagus.

Evaluation of heterogeneity of DNA ploidy in early gastric cancers

DNA ploidy has been shown to be a predictive parameter for prognosis in various solid tumours. The prognostic value of DNA-ploidy in gastric cancers is still a matter of controversy. A possible explanation for the discrepant results reported in the literature could be sampling error in tumours with multiple stemlines differing in DNA-ploidy. In order to determine whether or not such heterogeneity exists in early gastric carcinoma, we have performed DNA cytophotometry on multiple samples of a group of 17 early gastric carcinomas, of which 8 were pure intramucosal and 9 were infiltrating into the submucosa. We found an aneuploid DNA-stemline in 8 (47%) early gastric cancers, more often in tumours invading into the submucosa (5/9) than in purely mucosal tumours (3/8). Multiple DNA-stemlines were found more frequently in submucosally infiltrating tumours (4/5). These results confirm the presence of DNA-aneuploid early gastric carcinoma which are frequently heterogeneous and suggest that heterogeneity occurs more frequently in tumours invading the submucosa. This heterogeneity is best detected by analysing multiple samples of tumours for DNA-ploidy.

Early gastric carcinoma with focal advanced cancer: a particular subtype of gastric carcinoma

Early gastric cancer (EGC) is defined as a carcinoma limited to the mucosa or mucosa and submucosa, irrespective of whether metastasis to lymph nodes has occurred. EGC presents a much more favorable prognosis than advanced gastric carcinoma (AGC), with a 5-year survival rate between 88% and 96% for EGC versus 45% to 50% for AGC. Moreover, some gastric cancers appear as a more or less extended EGC with focal AGC (fAGC). The purpose of this study was to analyze prognostic factors in this intermediate group of tumors. From 1981 to 1992, among the 615 gastrectomy specimens with carcinoma examined at the Institute of Pathology of the University of Lausanne, only 19 tumors corresponded to the criteria of EGC with fAGC. Clinicopathologic features were studied, and a cytophotometric DNA analysis was performed. Our results show a 5-year survival rate for EGC with fAGC of 61% (11 of 18 patients alive), intermediate between that of EGC and AGC. No significant correlations were found between the most known predictive factors and prognosis. Most tumors analyzed (16 of 19) showed a diploid DNA content in the superficial as well as in the invasive areas. Contrary to the findings in the literature, which show a high-ploidy DNA pattern in most AGC, our cases show low-ploidy DNA even in the invasive portion of the tumors. In conclusion, we show that EGC with focal AGC represents a gastric cancer with an intermediate prognosis and, therefore, must be considered as a specific subtype of gastric carcinoma.

Effects of chronic NO synthase inhibition in rats on renin-angiotensin system and sympathetic nervous system

This study was designed to assess the role of renin and of the sympathoadrenal system in the maintenance of the hypertension induced by chronic nitric oxide synthase (NOS) inhibition in rats kept on a normal (RS) or a low-sodium (LS) diet. With the administration of NG-nitro-L-arginine methyl ester (L-NAME) in drinking water (0.4 milligrams) for 6 wk, mean intra-arterial blood pressure rose to a similar extent to 201 mmHg in the RS and 184 mmHg in the LS animals. Simultaneously, plasma norepinephrine was increased to 838 and 527 pg/ml and epinephrine to 2,041 and 1,341 pg/ml in RS and LS, respectively. Plasma neuropeptide Y levels did not change. Plasma renin activity rose to 21 ng.ml-1.h-1 in RS but remained at 44 ng.ml-1.h-1 in the LS. Both losartan (10 mg/kg) and phentolamine (0.1 mg/kg) intravenous bolus injections reduced blood pressure considerably in the L-NAME hypertensive animals. Whole brain NOS activity was reduced by 84%. Hypertension induced by chronic NOS inhibition in LS as well as in RS fed rats seems to be sustained by an interaction of several mechanisms, including the activation of the sympathetic nervous system and the renin-angiotensin system.

Long-term nitric oxide synthase inhibition and distensibility of carotid artery in intact rats

The goal of the present study was to evaluate the effect of long-term nitric oxide synthase inhibition by NG-nitro-L-arginine-methyl ester (L-NAME) on the morphology and viscoelastic properties of the carotid arteries in rats. Twelve-week-old Wistar-Kyoto rats were treated for 6 weeks with either the nitric oxide synthase inhibitor L-NAME (0.4 g/L in drinking water; L-NAME rats, n = 13) or tap water (control rats, n = 13). Age-matched spontaneously hypertensive rats (SHR, n = 14) received tap water for the same period. The internal diameter of the common carotid artery was measured continuously with an echo-tracking device with the rats under anesthesia with halothane. Intra-arterial pressure was monitored on the contralateral side. L-NAME rats exhibited arterial pressures similar to those of SHR. The distensibility pressure-curve determined in L-NAME rats was a direct continuation of that obtained in control rats. In contrast the distensibility in SHR was increased (P < .01, SHR versus L-NAME rats). Carotid artery cross-sectional area and left ventricular weight index were increased similarly in SHR and L-NAME rats compared with control rats. Thus the hypertension caused by long-term nitric oxide synthesis inhibition was not associated with the increased arterial distensibility observed in SHR despite similar blood pressure elevations, similar arterial hypertrophy, and consequently similar wall stress. This suggests a role for nitric oxide in regulating the mechanical behavior of arteries exposed to high blood pressure.

Localization of neuropeptide Y and its C-terminal flanking peptide in human renal tissue

We produced and characterized three anti-C-flanking peptides of neuropeptide Y (CPON) monoclonal antibodies. The Ka for these antibodies ranged from 0.4 to 0.8 x 10(8) l/mol with an IC50 for CPON(1-30) at about 20 nM as determined by ELISA. All these antibodies are IgG1 and recognize the 16-30 part of CPON. These antibodies and a specific anti-NPY monoclonal antibody were used to study the localization of CPON and NPY in the human kidney. The avidin-biotin technique was employed. NPY and CPON immunoreactivities were present in large amount in the renal tubules of the human kidney but not in the glomeruli. No labeling was found within the renal arterioles and veins, but some immunoreactivity was evidenced in the perivascular area. Because no specific receptor for CPON has been described to date, the presence of this peptide in the tubules may be due to a tubular reabsorption or perhaps to a local synthesis of pro-NPY.