Ultrasonographic evaluation of the caudal vena cava in dogs with right-sided heart disease

INTRODUCTION/OBJECTIVES

In humans with impaired right-sided cardiac function, the caudal vena cava (CVC) diameter serves as a marker of venous congestion. This study aimed to investigate whether ultrasonographic CVC variables could identify the presence of right-sided congestive heart failure (R-CHF) in dogs with right-sided heart disease (RHD).

ANIMALS

Fifty client-owned control dogs and 67 dogs with RHD were enrolled. The dogs with RHD were subdivided into the non-R-CHF (n = 43) and R-CHF (n = 24) groups.

MATERIALS AND METHODS

We measured and compared the ultrasonographic CVC variables and echocardiographic variables among the groups. Receiver operating characteristic (ROC) curve analysis was performed to calculate the sensitivity and specificity of the variables at optimal cutoff values.

RESULTS

We obtained the highest accuracies of the ratio of the shortest diameter (SD) of the minimal CVC area to the aorta diameter (Ao) during inspiration [SD(min)/Ao] and of the ratio of SD(min) to the longest diameter of the minimal CVC area during inspiration [LD(min),SD/LD(min)], with high sensitivities, specificities, and an area under the ROC curve greater than 0.925.

CONCLUSIONS

In addition to the echocardiographic assessment of right-sided cardiac function, the CVC variables in this study, especially SD(min)/Ao and SD/LD(min), would be useful diagnostic indices for identifying R-CHF in dogs with RHD.

Seasonal monitoring of Hida salamander Hynobius kimurae using environmental DNA with a genus-specific primer set

The diversity and the abundance of amphibians have dramatically declined globally over the past 30 years, and the monitoring and conservation of their habitats is essential. However, traditional methods such as bait trapping and mark-recapture are costly, and morphological identification usually requires a high level of taxonomic expertise. Here, seasonal surveillances of Hida salamanderHynobius kimuraewere performed by means of environmental DNA (eDNA) analysis withHynobius-specific primers and a species-specific TaqMan probe. Water sampling and visual surveys were conducted seasonally in a stream in Kyoto Prefecture, Japan. Detection rates of eDNA were then calculated by real-time PCR, and eDNA site occupancy probability was estimated by multi-scale occupancy modeling. The eDNA-based detection rate of Hida salamander was 76.7%, whereas the visual survey-based detection rate was 23.3%, and target eDNA was detected at almost all sites where the presence of target species was visually confirmed. Moreover, factors relating to the site- and sample-level occurrence probabilities of the target eDNA differed depending on the developmental stage of the target species. Our findings support previous studies showing that eDNA analysis enables an effective assessment of amphibian distributions without damaging the organisms or their habitat, and we compare for the first time the site occupancy probability of amphibian eDNA throughout the life cycle of an amphibian species. The present study contributes to the development of eDNA analysis as a tool for understanding the distribution and seasonal activity of amphibian species and will thus aid in the planning of conservation measures and habitat restoration for these species.

Novel lipoprotein density profiling in laminitic, obese, and healthy horses

Lipoproteins are water-miscible macromolecules enabling the transport of lipids in blood. In humans, altered proportions of lipoproteins are used to detect and classify metabolic diseases. Obesity and obesity-related comorbidities are common in horses. The pathophysiology of obesity is poorly understood and likely multifactorial. Development of new diagnostic tests to identify horses at risk of developing obesity to implement preventative measures is critical; however, a necessary first step to accomplish this goal is to improve our understanding of the pathophysiology of disease. Thus, the objective of this study was to characterize and compare lipoprotein profiles of horses with normal and excess body conditions, with and without laminitis using a novel method of continuous lipoprotein density profiling (CLPDP). Comparisons were made between 4 groups of horses: (1) laminitic, obese horses (n = 66); (2) laminitic, nonobese horses (n = 35); (3) nonlaminitic, obese horses (n = 41); and (4) nonlaminitic, nonobese horses (n = 95). Lipoprotein profiling, including evaluation of triglyceride-rich lipoprotein (TRL), low-density lipoproteins (LDLs), and high-density lipoproteins (HDLs) was performed using CLPDP, and all 4 groups were compared. A significant difference was observed among groups for the subfractions TRL, LDL1, LDL2, HDL2b, HDL2a, HDL3a, HDL3b, HDL3c, and total HDL. This is the first known description of CLPDP to characterize equine lipid profiles and holds promise as a useful method for lipid characterization of horses.

MiFish, a set of universal PCR primers for metabarcoding environmental DNA from fishes: detection of more than 230 subtropical marine species

We developed a set of universal PCR primers (MiFish-U/E) for metabarcoding environmental DNA (eDNA) from fishes. Primers were designed using aligned whole mitochondrial genome (mitogenome) sequences from 880 species, supplemented by partial mitogenome sequences from 160 elasmobranchs (sharks and rays). The primers target a hypervariable region of the 12S rRNA gene (163-185 bp), which contains sufficient information to identify fishes to taxonomic family, genus and species except for some closely related congeners. To test versatility of the primers across a diverse range of fishes, we sampled eDNA from four tanks in the Okinawa Churaumi Aquarium with known species compositions, prepared dual-indexed libraries and performed paired-end sequencing of the region using high-throughput next-generation sequencing technologies. Out of the 180 marine fish species contained in the four tanks with reference sequences in a custom database, we detected 168 species (93.3%) distributed across 59 families and 123 genera. These fishes are not only taxonomically diverse, ranging from sharks and rays to higher teleosts, but are also greatly varied in their ecology, including both pelagic and benthic species living in shallow coastal to deep waters. We also sampled natural seawaters around coral reefs near the aquarium and detected 93 fish species using this approach. Of the 93 species, 64 were not detected in the four aquarium tanks, rendering the total number of species detected to 232 (from 70 families and 152 genera). The metabarcoding approach presented here is non-invasive, more efficient, more cost-effective and more sensitive than the traditional survey methods. It has the potential to serve as an alternative (or complementary) tool for biodiversity monitoring that revolutionizes natural resource management and ecological studies of fish communities on larger spatial and temporal scales.

Lineage-specific RUNX3 hypomethylation marks the preneoplastic immune component of gastric cancer

Runt domain transcription factor 3 (RUNX3) is widely regarded as a tumour-suppressor gene inactivated by DNA hypermethylation of its canonical CpG (cytidine-phosphate-guanidine) island (CGI) promoter in gastric cancer (GC). Absence of RUNX3 expression from normal gastric epithelial cells (GECs), the progenitors to GC, coupled with frequent RUNX3 overexpression in GC progression, challenge this longstanding paradigm. However, epigenetic models to better describe RUNX3 deregulation in GC have not emerged. Here, we identify lineage-specific DNA methylation at an alternate, non-CGI promoter (P1) as a new mechanism of RUNX3 epigenetic control. In normal GECs, P1 was hypermethylated and repressed, whereas in immune lineages P1 was hypomethylated and widely expressed. In human GC development, we detected aberrant P1 hypomethylation signatures associated with the early inflammatory, preneoplastic and tumour stages. Aberrant P1 hypomethylation was fully recapitulated in mouse models of gastric inflammation and tumorigenesis. Cell sorting showed that P1 hypomethylation reflects altered cell-type composition of the gastric epithelium/tumour microenvironment caused by immune cell recruitment, not methylation loss. Finally, via long-term culture of gastric tumour epithelium, we revealed that de novo methylation of the RUNX3 canonical CGI promoter is a bystander effect of oncogenic immortalization and not likely causal in GC pathogenesis as previously argued. We propose a new model of RUNX3 epigenetic control in cancer, based on immune-specific, non-CGI promoter hypomethylation. This novel epigenetic signature may have utility in early detection of GC and possibly other epithelial cancers with premalignant immune involvement.

Detection of ki-ras mutation in nonneoplastic mucosa of Japanese patients with colorectal cancers

About 50% of colorectal adenocarcinoma in humans have been reported to contain mutated Ki-ras gene. To provide a better understanding for the possible role of this mutation and to examine whether its presence can reliably predict a risk of colorectal cancer, we have analyzed the normal appearing mucosa of patients with colorectal adenocarcinoma. With an Enriched PCR procedure, we can detect mutated Ki-ras allele in the presence of 10(3) to 10(4) normal alleles. Only by this procedure was Ki-ras mutation detected in the non-neoplastic colonic mucosa of 9 out of 50 (18%) Japanese patients with colorectal cancer. This analysis indicated that epithelial cells which carry mutated Ki-ras gene were 100- to 1000-fold less frequent in the non-neoplastic mucosa than at the tumor site. The presence of ras gene mutation in normal appearing mucosa points to a previous exposure which had initiated the multistage process of colorectal carcinogenesis.

Inflammation-induced repression of tumor suppressor miR-7 in gastric tumor cells

Inflammation has an important role in cancer development through various mechanisms. It has been shown that dysregulation of microRNAs (miRNAs) that function as oncogenes or tumor suppressors contributes to tumorigenesis. However, the relationship between inflammation and cancer-related miRNA expression in tumorigenesis has not yet been fully understood. Using K19-C2mE and Gan mouse models that develop gastritis and gastritis-associated tumors, respectively, we found that 21 miRNAs were upregulated, and that 29 miRNAs were downregulated in gastric tumors in an inflammation-dependent manner. Among these miRNAs, the expression of miR-7, a possible tumor suppressor, significantly decreased in both gastritis and gastric tumors. Moreover, the expression of miR-7 in human gastric cancer was inversely correlated with the levels of interleukin-1β and tumor necrosis factor-α, suggesting that miR-7 downregulation is related to the severity of inflammatory responses. In the normal mouse stomach, miR-7 expression was at a basal level in undifferentiated gastric epithelial cells, and was induced during differentiation. Moreover, transfection of a miR-7 precursor into gastric cancer cells suppressed cell proliferation and soft agar colony formation. These results suggest that suppression of miR-7 expression is important for maintaining the undifferentiated status of gastric epithelial cells, and thus contributes to gastric tumorigenesis. Although epigenetic changes were not found in the CpG islands around miR-7-1 of gastritis and gastric tumor cells, we found that activated macrophage-derived small molecule(s) (<3 kDa) are responsible for miR-7 repression in gastric cancer cells. Furthermore, the miR-7 expression level significantly decreased in the inflamed gastric mucosa of Helicobacter-infected mice, whereas it increased in the stomach of germfree K19-C2mE and Gan mice wherein inflammatory responses were suppressed. Taken together, these results indicate that downregulation of tumor suppressor miR-7 is a novel mechanism by which the inflammatory response promotes gastric tumorigenesis.

Endosonographic evaluation of c-kit-positive gastrointestinal stromal tumor

BACKGROUND

Endosonographic features of c-kit-positive gastrointestinal stromal tumors (GISTs) were compared with those of leiomyomas and schwannomas.

METHODS

Twenty-four patients with gastric mesenchymal tumors who underwent endoscopic ultrasonography (EUS) and surgical treatment were enrolled. GISTs were defined as c-kit (CD117)-positive tumors, leiomyomas as desmin-positive and c-kit-negative tumors, and schwannomas as S-100-positive and c-kit-negative tumors. Invasion to adjacent organs or more than 20 mitotic counts per 50 high power fields indicated malignancy.

RESULTS

There were 19 GISTs, three leiomyomas, and two schwannomas. All five malignant tumors were GISTs. A marginal halo was found in 12 of 19 GISTs and in both of the schwannomas, but not in any of the three leiomyomas. The echogenicities of GISTs were low but higher than that of the normal proper muscle layer, whereas those of leiomyomas and schwannomas were usually low. Lobulation of the tumor surface was documented only in GISTs, particularly in malignant ones. The tumor doubling time of a malignant GIST was 9.3 months, and that of six benign GISTs was 18.7 months (range = 10.7-28.0 months).

CONCLUSION

Marginal halo and relatively higher echogenicity on EUS might suggest GIST. Marginal lobulation and a short doubling time may be signs of a malignant GIST.

Visualizing the gastric wall with a 30-MHz ultrasonic miniprobe: ex vivo imaging of normal gastric sites and sites of early gastric cancer

BACKGROUND

This study was performed to determine the echo layer structures of the normal gastric wall and early gastric cancer when visualized with a 30-MHz ultrasonic miniprobe.

METHODS

Twelve surgically resected gastric specimens were used for an ex vivo study. Eighteen normal sites and 12 early gastric cancer sites were scanned with an Olympus (XUM-S30-25R) probe with a frequency of 30-MHz. Endoscopic ultrasound images were compared with corresponding histopathologic sections stained with hematoxylin and eosin.

RESULTS

The normal mucosa was visualized as at least four alternating echo layers; the muscularis mucosa was delineated at all normal sites. Lymphoid aggregates within the mucosa could be seen. The submucosa was clearly visualized in most cases, but the muscularis propria and subserosa were seldom depicted due to attenuation of ultrasound waves. At the sites of gastric cancer, the layered architecture of the mucosa was disturbed by an irregular hypoechoic lesion. Minimal submucosal infiltration (400 and 750 micrometer) was clearly depicted in two cases, without ulceration at or around the tumor site. However, attenuation at the site of a deep ulcer scar prevented adequate visualization of the tumor extent in two other cases with ulceration.

CONCLUSION

A 30-MHz ultrasonic miniprobe may provide additional imaging information of the gastric wall and could play a role in the assessment of early cancer lesions.

Gene mutation as a target for early detection in cancer diagnosis

The increasing number of genetic aberrations implicated in the development of human cancer has prompted a search to detect them at the earliest possible stage of their formation. Of the many such genetic changes identified thus far, relatively few meet the standard for markers in early diagnosis and prognosis, namely that the genetic modifications occur during the early onset phase of cancer development. Parallel to the increasing number of such genes is the growing availability of technologies using more powerful and cost-efficient methods that enable mass screening for genetic alterations. The purpose of this review is to summarize the currently available genes that can serve as markers for early detection of cancers and methods that allow their detection.

Distinct pattern of p53 phosphorylation in human tumors

The protein product of the tumor suppressor gene p53 is phosphorylated on multiple residues by several protein kinases. Using a battery of 10 antibodies developed against different phosphorylated and acetylated residues of p53, we compared the pattern of p53 phosphorylation and acetylation in tumor-derived cell lines, tumor samples, and non-neoplastic cells. Irrespective of tumor types or the presence of p53 mutation, phosphorylation and acetylation of p53 was substantially higher in samples obtained from tumor tissues than those found in non-transformed samples. Among the 10 sites analysed, phosphorylation of residues 15, 81, 392, and acetylation were among the more frequent modifications. Analysis of two of the more abundant phosphorylation or acetylation sites on p53 is sufficient to detect 72% of tumor-derived p53 proteins. The distinct pattern of p53 phosphorylation and acetylation in human tumors may offer a new means to monitor the status and activity of p53 in the course of tumor development and progression.

Jun NH2-terminal kinase phosphorylation of p53 on Thr-81 is important for p53 stabilization and transcriptional activities in response to stress

The p53 tumor suppressor protein plays a key role in the regulation of stress-mediated growth arrest and apoptosis. Stress-induced phosphorylation of p53 tightly regulates its stability and transcriptional activities. Mass spectrometry analysis of p53 phosphorylated in 293T cells by active Jun NH2-terminal kinase (JNK) identified T81 as the JNK phosphorylation site. JNK phosphorylated p53 at T81 in response to DNA damage and stress-inducing agents, as determined by phospho-specific antibodies to T81. Unlike wild-type p53, in response to JNK stimuli p53 mutated on T81 (T81A) did not exhibit increased expression or concomitant activation of transcriptional activity, growth inhibition, and apoptosis. Forced expression of MKP5, a JNK phosphatase, in JNK kinase-expressing cells decreased T81 phosphorylation while reducing p53 transcriptional activity and p53-mediated apoptosis. Similarly transfection of antisense JNK 1 and -2 decreased T81 phosphorylation in response to UV irradiation. More than 180 human tumors have been reported to contain p53 with mutations within the region that encompasses T81 and the JNK binding site (amino acids 81 to 116). Our studies identify an additional mechanism for the regulation of p53 stability and functional activities in response to stress.

Altered expression of p53 and p27 proteins, alone or combined, as a predictor of metastatic potential in early invasive carcinoma of colon and rectum--a comparative clinicopathologic and molecular analysis

To place the choice of therapy (endoscopic resection or radical surgery) in early invasive carcinoma (EIC) of colon and rectum on a more rational basis, this study sought to identify molecular predictors of metastasis. Several morphologic risk factors (histologic type, degree of tumor invasion, lymphatic and venous invasion) and expression of p53 and p27 proteins in the primary tumor were compared in 80 patients with EIC, including 12 (15%) with metastasis or recurrence (or both). Of the factors enumerated, deeper invasion of the submucosal layer, lymphatic-venous invasion, p53 overexpression, and decreased expression of p27 were correlated significantly with metastasis. The results also indicated that altered expression of p53 or p27 is independently relevant to metastasis of EIC. Analysis of these markers, together with determination of the morphologic risk factors, could complement the identification of patients with metastasis on the basis of known morphologic risk factors. Because the molecular factors can be assessed more objectively than can the morphologic parameters, they may strengthen the ability to identify EIC that has undergone, or will undergo, metastasis.

Presacral ganglioneuroma arising in an elderly man with persistent constipation

Presacral ganglioneuroma in a 70-year-old man with persistent constipation and its features on computed tomography, magnetic resonance, and endoscopic ultrasonography are presented. Barium enema study and laparotomy showed that constipation was caused mainly by extrinsic compression from this tumor. Computed tomography, magnetic resonance, endoscopic ultrasonographic features such as well-defined solid tumor with a cystic component and punctate calcifications may facilitate early diagnosis of this rare tumor.

Altered expression of beta-catenin and c-erbB-2 in early gastric cancer

To investigate the possible relationship between altered expression (loss of membranous staining or nuclear accumulation) of beta-catenin and invasion/metastasis in early gastric cancer (EGC), beta-catenin was detected immunohistochemically in 116 cases of EGC, including 86 differentiated and 30 undifferentiated carcinomas. In parallel, immunohistochemical expression of c-erbB-2 was analyzed in all EGC cases. Regardless of histological type, altered expression of beta-catenin was found in 47% of mucosal carcinomas and 89% of carcinomas with submucosal invasion (p<0.001). Of particular interest is that beta-catenin alteration was found in almost all EGCs with lymph node metastasis, even though no significant statistical comparison could be made. These results suggest that molecular changes resulting in abnormal beta-catenin expression participate in the process of submucosal invasion and metastasis. While loss of expression was preferentially observed in undifferentiated EGCs, nuclear accumulation was found exclusively in 24% of differentiated EGCs. c-erbB-2 was overexpressed in only 16% of differentiated EGCs but there was no correlation between this overexpression and invasion or metastasis. However, it is intriguing that 12 out of 14 cases with c-erbB-2 overexpression also showed altered beta-catenin expression, suggesting that both molecules are involved in the development of a certain set of differentiated EGCs.

Quantitative enriched PCR (QEPCR), a highly sensitive method for detection of K-ras oncogene mutation

We have developed a rapid and highly sensitive method for the detection of mutant K-ras codon 12 allele in the presence of 10(5) copies of the wild-type alleles. This sensitivity is achieved by selective amplification of mutant K-ras sequences, using a two-stage procedure with modified primers. In the first stage, primers consist of K-ras sequences in the 3' portion and polyomavirus sequence (to minimize homology with human genome) on the 5' portion. The 3' portion also consists of mismatch sequence that generates an MvaI site in normal, but not mutant, K-ras codon 12 alleles. Thus, following the first round of 20 cycles, restriction enzyme cleavage is carried out to selectively digest normal K-ras codon 12 alleles. To enrich mutant alleles, a second amplification is performed using tail primers that recognize the polyoma, but not human sequences. This design ensures that in the second amplification only mutant alleles that were pre-amplified in the first round would serve as template for this reaction. Ethidium bromide-stained polyacrylamide gel electrophoresis (PAGE) of second-stage PCR product that has been digested with MvaI is used to monitor the presence of mutant alleles, detected at sensitivity of 1/10(5). This technique offers high sensitive detection of mutant K-ras alleles using a new concept of tail-primer design and is likely to assist in identifying patients at risk to develop pancreatic, colon, or lung cancer, which harbor high incidence of mutant ras alleles.

K-ras mutation: early detection in molecular diagnosis and risk assessment of colorectal, pancreas, and lung cancers--a review

Multiple genomic alterations are involved in the development of most human cancers. They include alterations in oncogenes, tumor suppressor genes, DNA mismatch repair and excision repair genes. Genetic testing for susceptibility has been a part of the management of patients with well-defined but uncommon hereditary cancers in which certain susceptible gene mutations are determined in the germ line. However, a molecular diagnostic approach to sporadic cancers, which comprise the vast majority of malignant tumors in human beings, is still under development. One of the best characterized tumor-related genes is K-ras, which somatically mutates in several types of sporadic human cancers. Since mutations of this gene occur exclusively in three hot spots (codons 12, 13 and 61), and are frequently detected and well characterized in colorectal, pancreas and lung cancers, molecular diagnosis and susceptibility (risk) assessment targeting K-ras mutations are being developed. For this purpose, sample collection methods that reflect the state of the entire affected organ are important. Clinical samples used for molecular diagnosis and risk assessment include stool and lavage fluid, pancreatic and duodenal juices, and sputum and lavage fluids for colorectal, pancreas and lung cancers, respectively. The reported incidence of K-ras mutations detected in these samples ranges from 7% to 80% for colorectal cancers, 25% to 87% for pancreatic cancers, and 25% to 48% for lung cancers. Incidence of mutations clearly depends on the sensitivity of the method for detecting the mutant K-ras allele, as well as the nature and the quality of the clinical samples. Various methods including plaque hybridization, dot blot hybridization, combined PCR and RFLP or SSCP, and sensitive PCR have been used, and they exhibited high specificity (75 to 100%) in detecting mutations. Molecular analysis is demonstrating promise in assessing susceptibility to, or risk of developing, sporadic cancers.

Wnt/beta-catenin signaling induces the expression and activity of betaTrCP ubiquitin ligase receptor

Beta-transducing repeat-containing protein (betaTrCP) targets the ubiquitination and subsequent degradation of both beta-catenin and IkappaB, thereby playing an important role in beta-catenin/Tcf and NF-kappaB-dependent signaling. Here evidence is presented that beta-catenin/Tcf signaling elevates the expression of betaTrCP mRNA and protein in a Tcf-dependent manner, which does not require betaTrCP transcription. Induction of betaTrCP expression by the beta-catenin/Tcf pathway results in an accelerated degradation of the wild-type beta-catenin, suggesting that the negative feedback loop regulation may control the beta-catenin/Tcf pathway. This signaling also upregulated NF-kappaB transactivation without affecting the activity of IkappaB kinase, thereby establishing that the maintenance of the betaTrCP level is important for coordination between beta-catenin/Tcf and NF-kappaB signaling.

Analysis of JNK, Mdm2 and p14(ARF) contribution to the regulation of mutant p53 stability

Identification of Mdm2 and JNK as proteins that target degradation of wt p53 prompted us to examine their effect on mutant p53, which exhibits a prolonged half-life. Of five mutant p53 forms studied for association with the targeting molecules, two no longer bound to Mdm2 and JNK. Three mutant forms, which exhibit high expression levels, showed lower affinity for association with Mdm2 and JNK in concordance with greater affinity to p14(ARF), which is among the stabilizing p53 molecules. Monitoring mutant p53 stability in vitro confirmed that, while certain forms of mutant p53 are no longer affected by either JNK or Mdm2, others are targeted for degradation by JNK/Mdm2, albeit at lower efficiency when compared with wt p53. Expression of wt p53 in tumor cells revealed a short half-life, suggesting that the targeting molecules are functional. Forced expression of mutant p53 in p53 null cells confirmed pattern of association with JNK/Mdm2 and prolonged half-life, as found in the tumor cells. Over-expression of Mdm2 in either tumor (which do express endogenous functional Mdm2) or in p53 null cells decreased the stability of mutant p53 suggesting that, despite its expression, Mdm2/JNK are insufficient (amount/affinity) for targeting mutant p53 degradation. Based on both in vitro and in vivo analyses, we conclude that the prolonged half-life of mutant p53 depends on the nature of the mutation, which either alters association with targeting molecules, ratio between p53 and targeting/stabilizing molecules or targeting efficiency.

Environmental factors as regulators and effectors of multistep carcinogenesis

This review highlights current knowledge of environmental factors in carcinogenesis and their cellular targets. The hypothesis that environmental factors influence carcinogenesis is widely supported by both epidemiological and experimental studies. The fact that only a small fraction of cancers can be attributed to germline mutations in cancer-related genes further buttresses the importance of environmental factors in carcinogenesis. Furthermore, penetrance of germline mutations may be modified by either environmental or other genetic factors. Examples of environmental factors that have been associated with increased cancer risk in the human population include chemical and physical mutagens (e.g. cigarette smoke, heterocyclic amines, asbestos and UV irradiation), infection by certain viral or bacterial pathogens, and dietary non-genotoxic constituents (e.g. macro- and micronutrients). Among molecular targets of environmental influences on carcinogenesis are somatic mutation (genetic change) and aberrant DNA methylation (epigenetic change) at the genomic level and post-translational modifications at the protein level. At both levels, changes elicited affect either the stability or the activity of key regulatory proteins, including oncoproteins and tumor suppressor proteins. Together, via multiple genetic and epigenetic lesions, environmental factors modulate important changes in the pathway of cellular carcinogenesis.

Collagen production by cultured human retinal pigment epithelial cells

We investigated extracellular matrix produced by human retinal pigment epithelial cells (RPE) in vitro using electron microscopy and enzyme linked immunosorbent assay (ELISA). The thickness of the matrix under the cell layer was about 30 microns after 360 days of culture. It consisted mainly of fibrous and granular components. Type IV and V collagen were detected but type I and III were not detected by ELISA. It appeared that RPE can secrete type IV and V collagen and form a thick membrane which may cause proliferative vitreoretinopathy (PVR) by contraction. Control of RPE proliferation and secretion of extracellular matrix is indispensable for prevention of PVR.

[Correlations between risk factors for metastasis in early tumors of the large intestine]

Intramucosal colorectal cancers (Tis) are treated by local excision. Controversies remain as to the management of patients with the submucosally invasive colorectal cancers (EIC). The decision for radical surgery or local excision depends on an estimate of the risk of metastases.

AIM

To estimate correlations between the risk factors for metastases in EIC and to evaluate the tests that identify the metastasising EICs. In the study, we investigated the relationships between selected prognostic factors (the gross appearance, depth of submucosal invasion, vessel invasion, grade, presence of adenoma component, and p53 overexpression) and the frequency of metastases in 64 EICs.

STATISTICAL ANALYSIS

Fisher's exact test and log-linear analysis. Tests' evaluation: sensitivity, specificity, predictive values. The metastases were detected in 11 tumours (17%). The metastases were found with the significantly (p < 0.05) higher frequency in moderately differentiated adenocarcinomas, in tumours with massive invasion, with vessel invasion, and with the p53 overexpression. The only interaction was between the grade and the depth of invasion. No other interaction between the risk factors was found with the multivariate analysis. The evaluation of the depth of invasion was characterised by the highest sensitivity in detecting metastases, and by the highest negative predictive value. The highest specificity and the positive predictive value were found for the evaluation of vessel invasion. The massive submucosal invasion, vessel invasion, moderately differentiated characteristics, and the p53 overexpression seem to be the independent risk factors for metastases in EIC. The evaluation of these factors should be helpful as prognostic tests and for the proper choice of the treatment modality for the patients with EIC.

Does p53 overexpression cause metastases in early invasive colorectal adenocarcinoma?

OBJECTIVE

To find out whether p53 overexpression correlates with metastatic potential and other adverse prognostic factors in early invasive colorectal carcinoma and whether measurement of the expression of p53 protein could be helpful in the choice of treatment (endoscopic/local or radical resection).

DESIGN

Retrospective study.

SETTING

University hospital, Japan.

SUBJECTS

Overexpression of p53 protein in the primary tumour was examined immunohistochemically in 50 patients with early invasive colorectal cancer.

MAIN OUTCOME MEASURES

Differences in p53 overexpression between subgroups.

RESULTS

Abnormal accumulation of nuclear p53 was detected in the primary tumour of 20 patients (40%) with early invasive colorectal cancer. We found p53-positive cells in 7 (78%) of 9 that had metastasised to regional lymph nodes or distant organs, or both, and in 13 (32%) of 41 that had not metastasised (p = 0.02). p53 Immunoreactivity was also present in 10 (71%) of 14 superficial (type II) lesions compared with 10 (28%) of 36 protruding (type I) ones (p = 0.009) and in 12 (57%) of 21 moderately differentiated adenocarcinomas compared with 8 (28%) of 29 well-differentiated adenocarcinomas (p = 0.045). There was no significant correlation between p53 overexpression and the depth of tumour invasion or angiolymphatic involvement. The p53-positive metastasising tumours had features that corresponded to those of early carcinoma arising de novo.

CONCLUSION

Our results seem to support the postulate that p53 overexpression in early invasive colorectal carcinomas is associated with an increase in their metastatic potential.

Combined analysis of microsatellite instability and K-ras mutation increases detection incidence of normal samples from colorectal cancer patients

Microsatellite instability (MI) and K-ras oncogene mutation have been widely used as biomarkers of genetic changes in colorectal cancer (CRC). Each of these biomarkers was independently found in normal-appearing colonic mucosa at stages preceding the development of CRC, albeit at a relatively low incidence. To assess the potential value of combined MI and K-ras mutation analysis in the detection of normal-appearing colonic mucosa samples taken from patients with CRC, we have chosen to analyze multiple (3-7) normal colonic mucosa samples and the respective colorectal tumor tissues from 20 patients with CRC. As a control, we have used 54 normal mucosa samples obtained from 9 autopsies of patients without CRC. In at least 1 of 5 loci analyzed, MI was found in 8 of 20 patients via analysis of multiple normal-appearing colonic mucosa samples from each patient. Combined analysis of MI and mutant ras alleles in normal-appearing colonic mucosa samples enabled the identification of 11 of 20 patients with CRC. None of the 54 normal colonic mucosa samples obtained from 9 patients without CRC were found to carry mutant ras or MI. The ability to detect 55% of patients with CRC via the analysis of normal mucosa samples provides an important advance in our approach toward early detection of individuals who may be at risk to develop this tumor type.

Conformation-dependent phosphorylation of p53

Phosphorylation of the p53 tumor suppressor protein is known to modulate its functions. Using bacterially produced glutathione S-transferase (GST)-p53 fusion protein and baculovirus-expressed histidine-tagged p53 ((His)p53), we have determined human p53 phosphorylation by purified forms of jun-N-kinase (JNK), protein kinase A (PKA), and beta subunit of casein kinase II (CKIIbeta) as well as by kinases present in whole cell extracts (WCEs). We demonstrate that PKA is potent p53 kinase, albeit, in a conformation- and concentration-dependent manner, as concluded by comparing full-length with truncated forms of p53. We further demonstrate JNK interaction with GST-p53 and the ability of JNK to phosphorylate truncated forms of GST-p53 or full-length (His)p53. Dependence of phosphorylation on conformation of p53 is further supported by the finding that the wild-type form of p53 (p53wt) undergoes better phosphorylation by CKIIbeta and by WCE kinases than mutant forms of p53 at amino acid 249 (p53(249)) or 273 (p53(273)). Moreover, shifting the kinase reaction's temperature from 37 degrees C to 18 degrees C reduces the phosphorylation of mutant p53 to a greater extent than of p53wt. Comparing truncated forms of p53 revealed that the ability of CKIIbeta, PKA, or WCE kinases to phosphorylate p53 requires amino acids 97-155 within the DNA-binding domain region. Among three 20-aa peptides spanning this region we have identified residues 97-117 that increase p53 phosphorylation by CKIIbeta while inhibiting p53 phosphorylation by PKA or WCE kinases. The importance of this region is further supported by computer modeling studies, which demonstrated that mutant p53(249) exhibits significant changes to the conformation of p53 within amino acids 97-117. In summary, phosphorylation-related analysis of different p53 forms in vitro indicates that conformation of p53 is a key determinant in its availability as a substrate for different kinases, as for the phosphorylation pattern generated by the same kinase.

Sclerosing pancreatitis showing rapidly progressive changes with recurrent mass formation

CONCLUSION

Sclerosing pancreatitis might develop repeatedly or might rapidly extend to the whole pancreas with recurrent mass formation.

BACKGROUND

Nothing is known concerning course or development of sclerosing pancreatitis.

METHODS

A 63-yr-old male was followed up for 2.5 yr.

RESULTS

The patient was admitted because of a tumor in the body and tail of the pancreas. Serum pancreatic enzymes were transiently elevated, but tumor markers were all negative. Imaging studies showed a tumor 7 cm in size. The main pancreatic duct was normal in the head and obstructed at the body on endoscopic retrograde pancreatography (ERCP). The K-ras oncogene mutation was positive in pure pancreatic juice. Distal pancreatectomy was performed because pancreatic cancer was highly suspected. Pathological findings showed that the tumor was a densely fibrotic mass without malignant cells. Inflammatory cell infiltration was observed in the stroma. One year later, another mass 3 cm in size was noted in the remnant pancreatic head. ERCP revealed diffuse irregular narrowing of the main pancreatic duct, its branches, and the common bile duct. Liver dysfunction improved and an elevation of serum pancreatic enzymes subsided without any specific treatment, and the mass diminished in size. The patterns of various imaging studies on the second tumor were the same as those of the previous resected mass. Corticosteroid was not administered.

Analysis of mutant K-ras in multiple sites of normal appearing mucosa of colorectal cancer patients

While 50% of colorectal tumors were found to harbor K-ms codon 12 mutation, only 18% of the respective patients contain this mutation in the normal appearing tissue when enriched PCR, a sensitive method that enables detection of one mutant allele in 10(4) normal alleles, is used. To determine whether the lower percentage could be attributed to the low incidence of this mutation or to the method of sampling, we have analyzed multiple normal appearing samples obtained from the same patient. Of 90 non-neoplastic mucosal samples collected from 20 patients with colorectal cancer, K-ras codon 12 mutation was identified in 6 samples taken from 5 patients. These results indicate that only one or two of the multiple samples contain mutant ras alleles. The presence of mutant ras alleles in the normal appearing tissues did not always correlate with that in the tumor site with respect to its presence and/or the type of base pair alterations, indicating independent or late events. While pointing to the importance of proper sampling method, the ability to detect ms mutation in normal mucosal tissues suggests it may serve as a useful biomarker of internal/external exposure which precede colorectal cancer development.

[Comparative study on biological difference between gastric cancer and colorectal cancer]

In this study, we investigated the clinico-pathologic characteristics of patients with adenocarcinoma of the stomach and those with colorectal carcinoma to compare early progression patterns of both tumors. Histologically, gastric and colorectal adenocarcinomas showed similar progression patterns, including the incidence of submucosal invasion, lymphatic infiltration and lymph node metastasis. One striking finding was in gross appearance in born tumors. In contrast to most gastric well differentiated adenocarcinoma (DTA), which showed superficial growth, colorectal DTAs mainly showed polypoid growth. However, the superficial-type colorectal DTAs invaded the submucosal layer more frequently than did polypoid DTAs and gastric DTAs. These findings indicate that superficial-type colorectal DTAs grow more rapidly and aggressively than do polypoid DTAs and gastric DTAs. In order to elucidate growth rates between gastric cancer and colorectal cancer with hepatic metastasis doubling time was measured by exponential growth of tumor marker (CEA or AFP). The doubling time of liver metastases calculated from tumor markers was 26.6 +/- 10.8 days for stomach cancer and 57.8 +/- 35.4 days for colorectal cancer; accordingly doubling time for gastric cancer was approximately half of that for colonic cancer. However, there were no other factors (age, sex, site, histologic type in stomach, tumor marker production, etc.) influencing doubling time.

Frequent and characteristic K-ras activation in aberrant crypt foci of colon. Is there preference among K-ras mutants for malignant progression?

BACKGROUND

To investigate very early lesion of colorectal cancer, K-ras activation and nuclear p53 accumulation were studied in aberrant crypt focus (ACF).

METHODS

ACF were microscopically identified in grossly normal mucosa of patients with colorectal cancer who underwent surgery. Each ACF was microdissected from the surgical specimen and divided into two pieces, one for histologic and immunohistochemical examinations and the other for K-ras activation. K-ras mutations in codons 12 and 13 were sequenced after being screened by polymerase chain reaction amplification followed by restriction fragment length polymorphism analysis. Intranuclear accumulation of p53 protein was immunostained with the avidin-biotin complex method.

RESULTS

ACF was predominantly distributed in the sigmoid colon and rectum, and its incidence was increased with age. Unexpectedly, ACF was very rare in colons of three patients with hereditary nonpolyposis colorectal carcinoma. K-ras mutations were detected in 58% (33 of 57) of ACF cases and in 44% (11 of 25) of adenocarcinoma cases. Although GTT mutation in codon 12 was predominantly observed in adenocarcinoma (10 of 11), GAT mutation (12 of 33) was as frequent as GTT mutation (11 of 33) in ACF together with mutation at codon 13 (7 of 33). No accumulation of p53 protein was found in any ACF.

CONCLUSION

ACF were not diagnosed as neoplasms histologically, but they were considered to be neoplastic lesions, and K-ras activation is one of the key events to form ACF. The G-T substitution in K-ras codon 12 may undergo malignant growth easily compared with G-A substitution in colorectal carcinogenesis.

Mutant K-ras in apparently normal mucosa of colorectal cancer patients. Its potential as a biomarker of colorectal tumorigenesis

BACKGROUND

The best way to reduce the incidence of colorectal cancer mortality would be to prevent this cancer. However, none of the biomarkers proposed can accurately identify persons at increased risk of colorectal cancer or those at low risk. As a possible genetic biomarker, K-ras mutations, which are frequently found in colorectal cancers, were analyzed in apparently normal colorectal mucosa.

METHODS

Nonneoplastic mucosa and tumor tissues were collected at surgery from 70 patients with colorectal cancer: one sample each from 50 patients (group A) and multiple samples from the other 20 patients (group B). Mutant K-ras codon 12 was analyzed by the enriched polymerase chain reaction (EPCR), by which one mutant can be detected among 10(3) to 10(4) normal alleles.

RESULTS

Only with the aid of EPCR was mutant K-ras detected in nonneoplastic mucosa of nine patients (18%) in Group A and five patients (25%) in Group B. This increased incidence could be attributed to the multiple tissue sampling. The presence of mutant K-ras in nonneoplastic mucosae was not consistently correlated with that in the tumors. These findings suggest that the mutant K-ras identified in nonneoplastic mucosa actually represents de novo mutations, which may be initiated by different etiologic factors and at different times.

CONCLUSION

Mutant K-ras detected in apparently normal mucosa should be a useful biomarker for identifying persons at higher risk of colorectal cancer. Our study also emphasizes the need for improving the method for sample collection to achieve true representation of the colorectal mucosa.

Frequent and characteristic K-ras activation and absence of p53 protein accumulation in aberrant crypt foci of the colon

BACKGROUND/AIMS

The relationship of aberrant crypt foci (ACF) to colorectal carcinogenesis is still controversial. Histological examination and analyses of K-ras mutations and p53 gene expression were performed to characterize ACF.

METHODS

ACF were identified microscopically in grossly normal colorectal mucosa. The ACF were separated into two pieces, one for histological and immunohistochemical examinations and the other for molecular analysis. K-ras mutations in codons 12 and 13 were analyzed by polymerase chain reaction amplification, followed by restriction fragment length polymorphism and sequencing analyses. Intranuclear p53 protein was immunostained by the avidin-biotin complex method.

RESULTS

Histologically, elongation and apical branching of the crypts in ACF were striking. K-ras mutations were detected in 58% of ACF (33 of 57; 46% [26 of 57] in codon 12, and 12% [7 of 57] in codon 13) and in 44% of adenocarcinomas (11 of 25; all in codon 12). In ACF, GAT mutations (12 of 26) were as frequent as GTT mutations (11 of 26) in codon 12, although GTT mutations in codon 12 were predominant in adenocarcinomas (10 of 11). No accumulation of p53 protein was detected in any ACF, although it was detected in 52% (13 of 25) of the colorectal carcinomas.

CONCLUSIONS

ACF do not seem histologically to be neoplasms, although genetically they are monoclonal lesions. K-ras mutation is critical in the formation of ACF, but p53 alteration could play a causal role in tumor progression.

Effect of docosahexaenoic acid on azoxymethane-induced colon carcinogenesis in rats

The effect of intragastric gavage administration of docosahexaenoic acid (DHA) on azoxymethane (AOM)-induced colon carcinogenesis in rats was studied. Male F344 rats were treated s.c. with 15 mg/kg of AOM once a week for 2 weeks and were given either 0.7 ml of DHA or water intragastrically twice a week starting the day before the first carcinogen treatment. The number of crypt multiplicity (number of crypts/focus) of aberrant crypt foci (ACF) in the colon were measured after 4, 12, and 36 weeks. The numbers and average crypt multiplicities of ACF induced by AOM were significantly lower after 12 and 36 weeks in animals given DHA. DHA also reduced the incidence of spontaneous ACF in animals without carcinogen treatment. Colorectal tumor incidence and number of tumors per rat after 36 weeks were slightly, but not significantly, lower in the DHA-treated group. These results suggest that DHA slightly suppresses colon carcinogenesis, and a possibility that warrants further study.

Increased cell proliferation of azoxymethane-induced aberrant crypt foci of rat colon

Aberrant crypt foci (ACF) were induced in the colon of F344 rats by s.c. injection of azoxymethane (AOM) twice in a three day-interval and examined after 4 and 12 weeks. The number and crypt multiplicity of ACF in each section of rat colon increased during this period. Histologically, aberrant crypts consisted of proliferating atypical epithelial cells. Cell proliferation of ACF consisting of 4 aberrant crypts [ACF(4)] and 2 aberrant crypts [ACF(2)], and normal crypts in the colon of rats treated with AOM [normal crypts/AOM(+)] or saline [normal crypts/AOM(-)] was investigated by measurement of the mitotic index, proliferating cell nuclear antigen-labeling index (PCNA-LI), and 5-bromo-2'-deoxyuridine-labeling index (BrdU-LI). All three parameters of the cell proliferative activity of ACF(4) were higher than those of normal crypts/AOM(+) and normal crypts/AOM(-). The PCNA-LI and BrdU-LI in ACF(2) were the same as those in ACF(4). These findings suggest that ACF have increased cell proliferative activity. The correlation of these three parameters confirmed that the PCNA-LI is also a useful parameter for evaluating cell proliferative activity in ACF. The presence of many cells stained by PCNA in the upper portion of ACF suggested that ACF have more G1 phase cells, which readily respond to mitogenic stimulation, than G0 phase cells, which are predominant in normal crypts.

Superficial-type adenomas and adenocarcinomas of the colon and rectum: a comparative morphological study

BACKGROUND/AIMS

It has been uncertain whether colorectal carcinomas preferentially arise on preexisting adenomas or de novo. However, from a morphological viewpoint, it seems unlikely that pedunculated or exophytic malignant polyps progress to the deeply ulcerated advanced carcinomas usually found clinically.

METHODS

The morphological features of 26 nonpolypoid, superficial-type colorectal tumors (17 adenomas and 9 adenocarcinomas) were compared to clarify the developmental route of colorectal carcinomas.

RESULTS

The adenomas and adenocarcinomas were very similar in size and gross appearance; however, examination of the surface appearances of unsectioned tumors by dissecting microscopy was helpful for distinguishing the two. Histologically, no adenomatous tissue was found in any case of superficial-type adenocarcinoma. Five of the nine adenocarcinomas, even including those of small size, invaded the submucosal layer, and two showed lymph node metastasis.

CONCLUSIONS

These findings suggest that superficial-type adenocarcinomas show rapid growth and aggressive behavior. We suggest that this type of carcinoma may not progress by the adenoma-to-carcinoma pathway but that it may arise from a very small superficial-type adenoma.

Infrequent K-ras activation in superficial-type (flat) colorectal adenomas and adenocarcinomas

Clinicopathological evidence is accumulating that a superficial-type (flat) colorectal tumor is a distinct neoplastic entity. To clarify the genetic characteristics of this tumor, we investigated the K-ras gene mutations and morphological features of 43 tumors of this type. A mutation of the K-ras codon 12 was detected in only 5 (16%) of 31 adenomas and 2 (17%) of 12 adenocarcinomas. The presence or absence of this mutation was not correlated with the tumor size or stage or with histopathological findings. None of these tumors had a mutation in codon 13 or exon 2, including codon 61. This low incidence of K-ras mutations (16%) suggests that superficial-type colorectal tumors are etiologically distinct from ordinary colorectal polypoid tumors and that there may be an alternative pathway of colorectal tumorigenesis.

Renal cell carcinoma producing alpha-fetoprotein (AFP) with a unique lectins-affinity profile

Renal cell carcinoma (RCC) producing alpha-fetoprotein (AFP) is a rare entity and merely 7 cases have been reported so far. The present case, a 71-year-old woman, showed a high serum AFP level of 204 ng/ml. The RCC of the autopsied right kidney consisted mainly of spindle-shaped or bizarre sarcomatous tumor cells. AFP was immunolocalized only in the concomitant clear cell component. Concanavalin A (Con A)-nonadsorption rate of serum AFP was 42%, which was an intermediate value between those of yolk sac tumors and metastatic liver carcinomas. Lens culinalis agglutinin (LCA)-affinity study of the patient's AFP showed an unknown peak X, which was eluted between the known peaks 2 and 3. These results suggest a certain structural alteration in carbohydrate moieties of the AFP derived from this RCC. A review of the clinicopathologic features of 8 patients with AFP-producing RCC was made to understand the pathophysiology of AFP-producing neoplasms.

Early invasive colorectal carcinomas metastatic to the lymph node with attention to their nonpolypoid development

Clinicopathologic study of six cases of early invasive colorectal carcinoma metastatic to lymph node was performed in order to elucidate possible characteristics relating to the risk of metastasis, with particular attention to the growth pattern of the primary tumor. All of the cases had at least one of the well-known risk factors for lymph node metastasis, including moderately or poorly differentiated histologic characteristics, considerable degree of submucosal invasion, and lymphatic invasion. An interesting finding of the present study was the identification of a nonpolypoid growth pattern with no concomitant adenomatous tissue, which seemed to be different from that of "malignant polyps" of previously reported cases showing adenoma-carcinoma sequence. This unique growth feature was found in all of the cases. Therefore, in addition to the accepted risk factors, nonpolypoid growth pattern and absence of adenomatous component may be risk factors predictive of nodal metastasis in patients with early invasive colorectal carcinoma.

High frequency and low specificity of ras gene mutations in rat Zymbal's gland tumors induced by 2-amino-3-methylimidazo[4,5-f]quinoline

The activating mutations of all three ras genes in rat Zymbal's gland tumors induced by a food mutagen, 2-amino-3-methylimidazo[4,5- f]quinoline (IQ) were analyzed. DNA fragments of the Ha-ras, Ki-ras and N-ras oncogenes were amplified from formalin-fixed and paraffin-embedded tissues by the polymerase chain reaction (PCR) and analyzed for activating mutations involving codons 12, 13 and 61 by oligonucleotide differential hybridization. All nine Zymbal's gland tumors examined, including three papillomas, were found to contain either an Ha-ras or Ki-ras mutation. These mutations were located in either codon 13 or 61 of Ha-ras, and in either codon 12 or 13 of Ki-ras. Of the nine mutations, three were G-->T, three were G-->C, two were G-->A and one was A-->T. Of the nine mutations, eight occurred at guanine bases and seven were transversions. There was no correlation between the types of mutations and the histological types of the tumors. These results suggest that ras gene activation is an important early event in the tumorigenesis induced by IQ in rat Zymbal's gland and that mutations at guanine bases are frequent, though the locations and types of the mutations are not highly specific.