Prevalence and distinctive biologic features of flat colorectal adenomas in a North American population

BACKGROUND & AIMS

To assess the prevalence of flat and depressed (F&D) colorectal adenomas in the United States, we performed a prospective study of 211 American patients.

METHODS

Dye-assisted colonoscopy was performed in the presence of both an American and a Japanese investigator.

RESULTS

F&D lesions were found in 22.7% of patients, and these were more likely to be adenomatous than polypoid lesions (82% vs. 67%; P = 0.03) and contained more invasive cancer (4.5% vs. 0%; P = 0.04), which also appeared to be at a disproportionately advanced stage. The average size of all F&D advanced lesions (high-grade dysplasia and cancer) was significantly smaller than comparable polypoid lesions (10.75 +/- 2.7 mm vs. 20 +/- 2.9 mm; P < 0.05). F&D adenomas showed significantly stronger fragile histidine triad (FHIT) expression and lower p53 reactivity than similarly sized polypoid adenomas, whereas proliferative and apoptotic indices were similar in both groups.

CONCLUSIONS

We conclude that there is a significant prevalence of colonic F&D colorectal adenomas in this country and that these lesions have significantly different biologic features than polypoid lesions. The clinical and epidemiologic implications of these findings for American patients need to be addressed in further studies.

Necrotizing angiitis of the small intestine related to AA-amyloidosis: a novel association

A 71-year-old man with intestinal pseudo-obstruction was found to have a diffusely thickened adynamic small bowel with AA-amyloid in submucosal vessels and muscularis propria, foreign body giant cell reaction to amyloid, and necrotizing angiitis. The mucosa was unremarkable. Immunostains demonstrated numerous CD68+ monocyte/macrophages and CD8+ T cells associated with the amyloid deposits. The patient had no evidence of systemic vasculitis and no underlying cause for AA-amyloidosis was identified. Necrotizing angiitis coexistent with amyloid angiopathy has been reported in brain and temporal arteries, but not in the gastrointestinal tract and not with AA-amyloid. The inflammatory cell infiltrates in this case are consistent with a foreign-body and/or cell-mediated immunologic reaction to AA-amyloid, although a role for these cells in amyloid formation cannot be excluded.

Increased sensitivity to dextran sodium sulfate colitis in IRE1beta-deficient mice

The epithelial cells of the gastrointestinal tract are exposed to toxins and infectious agents that can adversely affect protein folding in the endoplasmic reticulum (ER) and cause ER stress. The IRE1 genes are implicated in sensing and responding to ER stress signals. We found that epithelial cells of the gastrointestinal tract express IRE1beta, a specific isoform of IRE1. BiP protein, a marker of ER stress, was elevated in the colonic mucosa of IRE1beta(-/-) mice, and, when exposed to dextran sodium sulfate (DSS) to induce inflammatory bowel disease, mutant mice developed colitis 3-5 days earlier than did wild-type or IRE1beta(+/-) mice. The inflammation marker ICAM-1 was also expressed earlier in the colonic mucosa of DSS-treated IRE1beta(-/-) mice, indicating that the mutation had its impact early in the inflammatory process, before the onset of mucosal ulceration. These findings are consistent with a model whereby perturbations in ER function, which are normally mitigated by the activity of IRE1beta, participate in the development of colitis.

Drug enterocyte adducts: possible causal factor for diclofenac enteropathy in rats

BACKGROUND & AIMS

Enteropathy is a frequent complication of diclofenac and other nonsteroidal anti-inflammatory drugs, yet little is known about the underlying mechanism. One possibility is that reactive metabolites of diclofenac form adducts with enterocyte macromolecules, as previously shown for liver. We addressed this possibility by using immunohistochemistry to detect diclofenac adducts.

METHODS

Rats were treated orally with diclofenac (10-100 mg/kg) and killed after 1-24 hours, and their gastrointestinal (GI) tracts were evaluated for ulcer number and area. Adduct distribution and intensity were assessed by immunohistochemistry by using a technique to simultaneously process and stain multiple intestinal rings.

RESULTS

Drug treatment led to dose-dependent formation of both adducts and ulcers only in small intestine and only in animals with intact enterohepatic circulation. Adducts formed within enterocytes by 1 hour, translocated to the brush border, preceded ulceration and vascular protein leakage, and were intense at sites of ulceration. Adducts and ulcers exhibited a parallel distribution within intestinal quintiles: 3rd > 5th >> 1st.

CONCLUSIONS

Diclofenac treatment resulted in the formation of drug adducts in enterocytes. Because this molecular change occurred before ulceration, was dose dependent, and exhibited concordant distribution with extent of ulceration, the results suggest a causal role for drug adduct formation in diclofenac enteropathy.

Recovery and identification of West Nile virus from a hawk in winter

West Nile virus was recovered from the brain of a red-tailed hawk that died in Westchester County, N.Y., in February 2000. Multiple foci of glial cells, lymphocytes, and a few pyknotic nuclei were observed in the brain. Three to 4 days after inoculation of Vero cells with brain homogenates, cytopathic changes were detected. The presence of West Nile virus antigen in fixed cells or cell lysates was revealed by fluorescent antibody testing or enzyme-linked immunosorbent assay, respectively. Furthermore, Reverse transcriptase-PCR with primers specific for the NS3 gene of West Nile virus resulted in an amplicon of the expected size (470 bp). Electron microscopy of thin sections of infected Vero cells revealed the presence of viral particles approximately 40 nm in diameter, within cytoplasmic vesicles. The demonstration of infection with the West Nile virus in the dead of the winter, long after mosquitoes ceased to be active, is significant in that it testifies to the survival of the virus in the region beyond mosquito season and suggests another route of transmission: in this case, prey to predator.

Gastroesophageal reflux disease, use of H2 receptor antagonists, and risk of esophageal and gastric cancer

OBJECTIVE

The incidence of esophageal adenocarcinoma has risen rapidly in the past two decades, for unknown reasons. The goal of this analysis was to determine whether gastroesophageal reflux disease (GERD) or the medications used to treat it are associated with an increased risk of esophageal or gastric cancer, using data from a large population-based case-control study.

METHODS

Cases were aged 30-79 years, newly diagnosed with esophageal adenocarcinoma (n = 293), esophageal squamous cell carcinoma (n = 221), gastric cardia adenocarcinoma (n = 261), or non-cardia gastric adenocarcinoma (n = 368) in three areas with population-based tumor registries. Controls (n = 695) were chosen by random digit dialing and from Health Care Financing Administration rosters. Data were collected using an in-person structured interview.

RESULTS

History of gastric ulcer was associated with an increased risk of non-cardia gastric adenocarcinoma (OR 2.1, 95% CI 1.4-3.2). Risk of esophageal adenocarcinoma increased with frequency of GERD symptoms; the odds ratio in those reporting daily symptoms was 5.5 (95% CI 3.2-9.3). Ever having used H2 blockers was unassociated with esophageal adenocarcinoma risk (OR 0.9, 95% CI 0.5-1.5). The odds ratio was 1.3 (95% CI 0.6-2.8) in long-term (4 or more years) users, but increased to 2.1 (95% CI 0.8-5.6) when use in the 5 years prior to the interview was disregarded. Risk was also modestly increased among users of antacids. Neither GERD symptoms nor use of H2 blockers or antacids was associated with risk of the other three tumor types.

CONCLUSIONS

Individuals with long-standing GERD are at increased risk of esophageal adenocarcinoma, whether or not the symptoms are treated with H2 blockers or antacids.

Aging enhances susceptibility of diclofenac-treated rats to gastric ulceration, while attenuating enteropathy

Although clinical reports note aging and gender as risk factors for NSAID therapy associated gastroenteropathy, neither variable has been examined in an animal model. We addressed this unknown by comparing the responses of young (4 months) and old (22 months) rats of both genders to oral treatment with diclofenac (10 or 50 mg/kg). Diclofenac produced gastric ulcers only in old rats, with markedly larger lesions in females. In contrast, the small intestines in old rats of both genders given the 50 mg/kg dosage had >30% fewer ulcers and a fourfold decrease in area of ulceration compared to young rats. The small intestine was the only site of lesions after the 10 mg/kg dosage and showed one gender influence, namely, a transiently faster time course of ulcer development in females. Old and young rats given 50 mg/kg showed similar declines in serum levels of the vascular permeability indices-total protein and albumin-despite reduced intestinal damage in the old animals, which suggests additive vascular leakage across the gastric lesions that were evident only in old animals. Serum biochemistry showed no evidence of hepatotoxicity or dysfunction, consonant with small intestine as the primary target for diclofenac toxicity in rats. We provide the first experimental evidence for an aging influence on the gastrointestinal target site of a nonaspirin NSAID.

The pathologic spectrum of gastrointestinal and hepatic histoplasmosis

We characterized the pathologic spectrum of lesions in gastrointestinal and hepatic histoplasmosis by studying cases of disseminated disease in immunocompromised and immunocompetent patients from endemic and nonendemic areas. We evaluated 56 specimens from 52 patients with H&E and silver stains. Of these patients, 43% presented with gastrointestinal rather than pulmonary symptoms. Thirty-one percent had gastrointestinal lesions, 10% had liver lesions, and 43% had both. Gross gastrointestinal features included ulcers (49% of patients), nodules (21%), hemorrhage (13%), obstructive masses (6%) and normal mucosa (23%). Microscopic gastrointestinal findings included diffuse lymphohistiocytic infiltration (83%), ulceration (45%), lymphohistiocytic nodules (25%), or minimal inflammatory reaction (15%) but only rare well-formed granulomas (8.5%). The most common hepatic finding was portal lymphohistiocytic inflammation; discrete hepatic granulomas were seen in less than 20% of involved livers. The pathologist must be aware of the broad range of gastrointestinal and hepatic lesions produced by histoplasmosis and, in particular, that well-formed granulomas are rare. Given the appropriate clinical context, histoplasmosis should be considered in both immunocompetent and immunocompromised patients, regardless of pulmonary symptoms, in nonendemic as well as endemic areas.

The effect of ursodeoxycholic acid on the florid duct lesion of primary biliary cirrhosis

The frequency with which florid duct lesions are seen in needle-biopsy specimens of the liver was assessed in patients with primary biliary cirrhosis (PBC) enrolled in a 2-year randomized, double-blind, placebo-controlled trial of ursodeoxycholic acid (UDCA) versus placebo. Paired biopsy specimens obtained at entry and after 2 years on medication were reviewed blindly and mostly simultaneously by a panel of 5 hepatopathologists who, earlier, had characterized the florid duct lesion, which has been well described in the pathology literature. Florid duct lesions at entry were identified in approximately 36%. Patients with earlier disease showed florid duct lesions much more frequently than those with more advanced disease. The prevalence of florid duct lesions in 60 patients receiving placebo medication fell from 38.3% to 21.7%, P =. 025, over the period of 2 years. The prevalence of florid duct lesions also decreased in the 55 patients receiving UDCA, from 32.7% to 18.2%, P =.046. The prevalences of these lesions in the placebo and UDCA patients at entry and at 2 years were not significantly different from each other. The findings suggest that UDCA does not prevent ongoing bile duct destruction in patients with PBC. Instead, they support the impression that UDCA exerts its beneficial effects by protecting against the consequences of bile duct destruction.

Myofibroblasts. II. Intestinal subepithelial myofibroblasts

Intestinal subepithelial myofibroblasts (ISEMF) and the interstitial cells of Cajal are the two types of myofibroblasts identified in the intestine. Intestinal myofibroblasts are activated and proliferate in response to various growth factors, particularly the platelet-derived growth factor (PDGF) family, which includes PDGF-BB and stem cell factor (SCF), through expression of PDGF receptors and the SCF receptor c-kit. ISEMF have been shown to play important roles in the organogenesis of the intestine, and growth factors and cytokines secreted by these cells promote epithelial restitution and proliferation, i.e., wound repair. Their role in the fibrosis of Crohn's disease and collagenous colitis is being investigated. Through cyclooxygenase (COX)-1 and COX-2 activation, ISEMF augment intestinal ion secretion in response to certain secretagogues. By forming a subepithelial barrier to Na(+) diffusion, they create a hypertonic compartment that may account for the ability of the gut to transport fluid against an adverse osmotic gradient. Through the paracrine secretion of prostaglandins and growth factors (e.g., transforming growth factor-beta), ISEMF may play a role in colonic tumorigenesis and metastasis. COX-2 in polyp ISEMF may be a target for nonsteroidal anti-inflammatory drugs (NSAIDs), which would account for the regression of the neoplasms in familial adenomatous polyposis and the preventive effect of NSAIDs in the development of sporadic colon neoplasms. More investigation is needed to clarify the functions of these pleiotropic cells.

Myofibroblasts. I. Paracrine cells important in health and disease

Myofibroblasts are a unique group of smooth-muscle-like fibroblasts that have a similar appearance and function regardless of their tissue of residence. Through the secretion of inflammatory and anti-inflammatory cytokines, chemokines, growth factors, both lipid and gaseous inflammatory mediators, as well as extracellular matrix proteins and proteases, they play an important role in organogenesis and oncogenesis, inflammation, repair, and fibrosis in most organs and tissues. Platelet-derived growth factor (PDGF) and stem cell factor are two secreted proteins responsible for differentiating myofibroblasts from embryological stem cells. These and other growth factors cause proliferation of myofibroblasts, and myofibroblast secretion of extracellular matrix (ECM) molecules and various cytokines and growth factors causes mobility, proliferation, and differentiation of epithelial or parenchymal cells. Repeated cycles of injury and repair lead to organ or tissue fibrosis through secretion of ECM by the myofibroblasts. Transforming growth factor-beta and the PDGF family of growth factors are the key factors in the fibrotic response. Because of their ubiquitous presence in all tissues, myofibroblasts play important roles in various organ diseases and perhaps in multisystem diseases as well.

Molecular characterization of the myxosporean associated with parasitic encephalitis of farmed Atlantic salmon Salmo salar in Ireland

During seasonal epizootics of neurologic disease and mass mortality in the summers of 1992, 1993 and 1994 on a sea-farm in Ireland, Atlantic salmon Salmo salar smolts suffered from encephalitis associated with infection by a neurotropic parasite. Based on ultrastructural studies, this neurotropic parasite was identified as an intercellular presporogonic multicellular developmental stage of a histozoic myxosporean, possibly a Myxobolus species. In order to generate sequence data for phylogenetic comparisons to substantiate the present morphological identification of this myxosporean in the absence of detectable sporogony, polymerase chain reaction (PCR), Southern blot hybridization, dideoxynucleotide chain-termination DNA sequencing, and in situ hybridization (ISH) were used in concert to characterize segments of the small subunit ribosomal RNA (SSU rRNA) gene. Oligonucleotide primers were created from sequences of the SSU rRNA gene of M. cerebralis and were employed in PCR experiments using DNA extracted from formalin-fixed paraffin-embedded tissue sections of brains from Atlantic salmon smolts in which the myxosporean had been detected by light microscopy. Five segments of the SSU rRNA gene of the myxosporean, ranging in length from 187 to 287 base pairs, were amplified, detected by hybridization with sequence-specific probes, and sequenced. Consensus sequences from these segments were aligned to create a partial sequence of the SSU rRNA gene of the myxosporean. Assessments of sequence identity were made between this partial sequence and sequences of SSU rRNA genes from 7 myxosporeans, including Ceratomyxa shasta, Henneguya doori, M. arcticus, M. cerebralis, M. insidiosus, M. neurobius, and M. squamalis. The partial SSU rRNA gene sequence from the myxosporean had more sequence identity with SSU rRNA gene sequences from neurotropic and myotropic species of Myxobolus than to those from epitheliotropic species of Myxobolus or Henneguya, or the enterotropic species of Ceratomyxa, and was identical to regions of the SSU rRNA gene of M. cerebralis. Digoxigenin-labeled oligonucleotide DNA probes complementary to multiple segments of the SSU rRNA gene of M. cerebralis hybridized with DNA of the parasite in histologic sections of brain in ISH experiments, demonstrating definitively that the segments of genome amplified were from the organisms identified by histology and ultrastructural analysis. Based on sequence data derived entirely from genetic material of extrasporogonic stages, the SSU rDNA sequence identity discovered in this study supports the hypothesis that the myxosporean associated with encephalitis of farmed Atlantic salmon smolts is a neurotropic species of the genus Myxobolus, with sequences identical to those of M. cerebralis.

Corticosteroids reverse the inhibition of Na-glucose cotransport in the chronically inflamed rabbit ileum

In a rabbit model of chronic ileal inflammation, we previously demonstrated inhibition of Na-glucose cotransport (SGLT-1). The mechanism of inhibition was secondary to a decrease in the number of cotransporters and not solely secondary to an inhibition of Na-K-ATPase or altered affinity for glucose. In this study, we determined the effect of methylprednisolone (MP) on SGLT-1 inhibition during chronic ileitis. Treatment with MP almost completely reversed the reduction in SGLT-1 in villus cells from the chronically inflamed ileum. MP also reversed the decrease in Na-K-ATPase activity in villus cells during chronic ileitis. However, MP treatment reversed the SGLT-1 inhibition in villus cell brush-border membrane vesicles from the inflamed ileum, which suggested an effect of MP at the level of the cotransporter itself. Kinetic studies demonstrated that the reversal of SGLT-1 inhibition by MP was secondary to an increase in the maximal velocity for glucose without a change in the affinity. Analysis of immunoreactive protein levels of the cotransporter demonstrated a restoration of the cotransporter numbers after MP treatment in the chronically inflamed ileum. Thus MP treatment alleviates SGLT-1 inhibition in the chronically inflamed ileum by increasing the number of cotransporters and not solely secondary to enhancing the activity of Na-K-ATPase or by altering the affinity for glucose.

Differential diagnosis of bile duct injury and ductopenia

Injury and loss of intrahepatic bile ducts are relatively common manifestations of liver disease in both adults and children. They occur in a wide variety of conditions ranging from developmental abnormalities and errors of metabolism to autoimmune disorders, infections, and iatrogenic states. Consequently the differential diagnosis is often complex. Moreover, although duct injury is generally easily detected in needle biopsy specimens, ductopenia is not infrequently both overlooked and overdiagnosed. This article reviews the differential diagnosis of duct injury and ductopenia in liver biopsy specimens and provides an algorithmic framework for narrowing down the differential diagnosis before correlation with the clinical findings.

Immunohistochemical detection of Listeria antigens in the placenta in perinatal listeriosis

Listeria monocytogenes, a worldwide pathogen, causes significant perinatal mortality and morbidity and has been implicated in spontaneous abortions, still-births, premature delivery, and neonatal sepsis, often with meningitis. Maternal symptoms are frequently minimal, and diagnosis is made only if the suspicion is high and diagnostic maternal blood or amniotic fluid cultures are performed. Because cultures are not routinely performed on spontaneously aborted fetuses, many authors feel that the true incidence of the disease may be underestimated. To date, the absence of a test to retrospectively diagnose Listeria infection has contributed to the lack of accurate estimates of the incidence of the disease. Seven cases in which immunohistochemical stains were used to confirm the diagnosis of placental listeriosis are described. All placentas showed the characteristic lesions with severe chorioamnionitis, numerous microabscesses, and focal necrotizing villitis. Immunohistochemical localization of Listeria antigen was made to the amnion (focally in areas with no inflammatory infiltrate), the abscesses, and the areas with villitis. In general, the antigen was extracellular and intracellular, predominantly within macrophages or the amnion epithelium. Listeria antigen was often found where definite identification of the organism was not possible on Brown-Hopps or Warthin-Starry stains. The immunohistochemical technique may therefore show an increase in sensitivity of detection of L monocytogenes compared with routine bacterial stains. Moreover, the ability to retrospectively evaluate placental specimens for evidence of this organism should permit the true incidence of perinatal listeriosis to be determined.

Risk of esophageal and gastric adenocarcinomas in relation to use of calcium channel blockers, asthma drugs, and other medications that promote gastroesophageal reflux

Incidence of adenocarcinomas of the esophagus and gastric cardia has risen dramatically over the past 2 decades in the U. S., for reasons that are not yet clear. A number of common medications (e.g., calcium channel blockers, tricyclic antidepressants, and certain asthma medications) promote gastroesophageal reflux by relaxing the lower esophageal sphincter (LES). Reflux is thought to increase cancer risk by promoting cellular proliferation, and by exposing the esophageal epithelium to potentially genotoxic gastric and intestinal contents. Recent studies have suggested that calcium channel blockers may also increase cancer risk by inhibiting apoptosis. Using personal interview data from a multicenter, population-based case-control study conducted between 1993 and 1995 in three areas of the U. S., we evaluated whether the use of LES-relaxing drugs was associated with increased risk of adenocarcinomas of the esophagus and gastric cardia. Cases of esophageal adenocarcinoma (n = 293) and gastric cardia adenocarcinoma (n = 261) were compared with general population controls (n = 695). Information on additional case groups of esophageal squamous cell carcinoma (n = 221) and noncardia gastric cancer (n = 368) were also available for comparison. Overall, 27.4% of controls had used one or more of these drugs for at least 6 months, compared with 30.2% of esophageal adenocarcinoma and 23.8% of gastric cardia adenocarcinoma cases. The adjusted odds ratios (ORs) for ever use were 1.0 [95% confidence interval (CI) = 0.7-1.5] and 0.8 (95% CI = 0.5-1.1), respectively. There was little evidence of increasing risk with increasing duration of use of all LES-relaxing drugs together. We found an increased risk of esophageal adenocarcinoma among persons reporting use of asthma drugs containing theophylline (OR = 2.5; 95% CI = 1.1-5.6) or beta agonists (OR = 1.7; 95% CI = 0.8-3.8). Risks were higher among long-term users (>5 years) of these drugs (OR = 3.1; 95% CI = 0.9-10.3 and OR = 2.3; 95% CI = 0.8-7.0, respectively). In contrast, there was no evidence that the use of calcium channel blockers or other specific groups of drugs increased the risk of any of the cancers studied. These results provide reassuring evidence that the increases in incidence of adenocarcinomas of the esophagus and gastric cardia are not likely to be related to the use of LES-relaxing drugs as a group, or calcium channel blockers in particular, but they do suggest that persons treated for long-standing asthma may be at increased risk of esophageal adenocarcinoma.

Epizootiology, pathology, and ultrastructure of the myxosporean associated with parasitic encephalitis of farmed Atlantic salmon Salmo salar in Ireland

In 1995 at a sea-farm in Ireland, Atlantic salmon Salmo salar smolts were introduced in the spring and autumn into 2 marine rearing sites, one with and one without recent histories of neurologic disease and mass mortality believed to be due to parasitic encephalitis. In order to monitor disease, determine the onset and anatomic distribution of parasites and encephalitis, and determine the ultrastructure and identity of the parasite, randomly selected smolts were necropsied from both sites at intervals of 1 to 3 d for periods of 1 to 2 mo, and clinical signs and cumulative mortalities were monitored. The prevalences of parasites and encephalitis were assessed by light microscopy, and sections of brain were examined by transmission electron microscopy. No clinical signs of neurologic disease were observed, but parasites and encephalitis were detected in smolts from both sites, with prevalences of each that were significantly greater in smolts from the site with recent disease. Based on light microscopy, the parasite was first detected in smolts sampled at 26 d post-introduction. Parasites were detected with significantly greater frequency in the optic tectum of the mesencephalon than in the diencephalon, metencephalon, and myelencephalon, and were not detected in the telencephalon. Foci of non-suppurative encephalitis were detected with significantly greater frequency in the myelencephalon than in each of the other 4 anatomic subdivisions. In each anatomic subdivision the prevalence of encephalitis was significantly greater than that of parasitic infection. The ultrastructure of the parasite was consistent with that of a histozoic presporogonic multicellular developmental stage of a myxosporean, characterized by intercellular branching tubular structures containing generative cells arranged individually or in cell-in-cell doublets. Parasitic stages were located between bundles of axons, with compression of axons along segments of their plasmalemma. No mature spores were detected.

Long-term symptom patterns, endoscopic findings, and gastric histology in Helicobacter pylori-infected and -uninfected patients

There is a paucity of data on the long-term behavior of dyspepsia, endoscopic findings, and gastroduodenal histology in patients with or without Helicobacter pylori colonization. We evaluated these parameters during a period of 7 to 19 years (average, 12.3 years) by baseline and follow-up studies. In 36 patients studied, the pattern of gastroduodenal dyspepsia and esophagogastroduodenoscopy findings remained essentially unchanged in 67% and 56% respectively. Dyspepsia patterns did not correlate significantly with either endoscopic or histologic findings, including the severity or location of gastritis in the fundus or antrum, or the presence or absence of H. pylori gastritis. Of 36 patients with adequate biopsies of the fundus and antrum, H. pylori colonization with gastritis was present in 73% but not in 27%. Progression to various degrees of atrophic gastritis was noted in 100% with, and in none without, H. pylori gastritis. In the fundus, atrophy progressed from 14% to 56%, but intestinal metaplasia did not change. In the antrum, atrophy increased from 22% to 64% and intestinal metaplasia increased from 17% to 36%. No patient demonstrated dysplasia, but severe atrophy was seen in the fundus (6%) and antrum (11%). Only two patients (5%) had severe loss of glandular elements and very low pepsinogen I, and thus can be considered to have developed advanced gastric atrophy.

An inverse relation between cagA+ strains of Helicobacter pylori infection and risk of esophageal and gastric cardia adenocarcinoma

Gastric colonization with Helicobacter pylori, especially cagA+ strains, is a risk factor for noncardia gastric adenocarcinoma, but its relationship with gastric cardia adenocarcinoma is unclear. Although incidence rates for noncardia gastric adenocarcinoma have declined steadily, paralleling a decline in H. pylori prevalence, rates for adenocarcinomas of esophagus and gastric cardia have sharply increased in industrialized countries in recent decades. To clarify the role of H. pylori infection in these tumors with divergent incidence trends, we analyzed serum IgG antibodies to H. pylori and to a recombinant fragment of CagA by antigen-specific ELISA among 129 patients newly diagnosed with esophageal/gastric cardia adenocarcinoma, 67 patients with noncardia gastric adenocarcinoma, and 224 population controls. Cancer risks were estimated by odds ratios (OR) and 95% confidence intervals (CI) using logistic regression models. Infection with cagA+ strains was not significantly related to risk for noncardia gastric cancers (OR, 1.4; CI, 0.7-2.8) but was significantly associated with a reduced risk for esophageal/cardia cancers (OR, 0.4; CI, 0.2-0.8). However, there was little association with cagA- strains of H. pylori for either cancer site (OR, 1.0 and 1.1, respectively). These findings suggest that the effects of H. pylori strains on tumor development vary by anatomical site. Further studies are needed to confirm these results and to assess whether the decreasing prevalence of H. pylori, especially cagA+ strains, may be associated with the rising incidence of esophageal/gastric cardia adenocarcinomas in industrialized countries.

Use of aspirin and other nonsteroidal anti-inflammatory drugs and risk of esophageal and gastric cancer

Regular users of aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) are at reduced risk of colon cancer, but the evidence for protective effects of NSAIDs elsewhere in the digestive tract is scant. We investigated the association between the use of NSAIDs and risk of esophageal and gastric cancer, using data from a large population-based, case-control study. Cases were individuals, ages 30-79 years, diagnosed with esophageal adenocarcinoma (n = 293), esophageal squamous cell carcinoma (n = 221), gastric cardia adenocarcinoma (n = 261), or noncardia gastric adenocarcinoma (n = 368) in three areas with population-based tumor registries. Controls (n = 695) were selected by random digit dialing and through the rosters of the Health Care Financing Administration. After controlling for the major risk factors, we found that current users of aspirin were at decreased risk of esophageal adenocarcinoma [odds ratio (OR), 0.37; 95% confidence interval (CI), 0.24-0.58], esophageal squamous cell carcinoma (OR, 0.49; 95% CI, 0.28-0.87), and noncardia gastric adenocarcinoma (OR, 0.46; 95% CI, 0.31-0.68), but not of gastric cardia adenocarcinoma (OR, 0.80; 95% CI, 0.54-1.19), when compared to never users. Risk was similarly reduced among current users of nonaspirin NSAIDs. The associations with current NSAID use persisted when we excluded use within 2 or 5 years of reference date, which might have been affected by preclinical disease in cases, and when we restricted analyses to subjects reporting no history of chronic gastrointestinal symptoms. Our findings add to the growing evidence that the risk of cancers of the esophagus and stomach is reduced in users of NSAIDs, although whether the association is causal in nature is not clear.

Body mass index and risk of adenocarcinomas of the esophagus and gastric cardia

BACKGROUND

Incidence rates have risen rapidly for esophageal adenocarcinoma and moderately for gastric cardia adenocarcinoma, while rates have remained stable for esophageal squamous cell carcinoma and have declined steadily for noncardia gastric adenocarcinoma. We examined anthropometric risk factors in a population-based case-control study of esophageal and gastric cancers in Connecticut, New Jersey, and western Washington.

METHODS

Healthy control subjects (n = 695) and case patients with esophageal squamous cell carcinoma or noncardia gastric adenocarcinoma (n = 589) were frequency-matched to case patients with adenocarcinomas of esophagus or gastric cardia (n = 554) by 5-year age groups, sex, and race (New Jersey only). Classification of cases by tumor site of origin and histology was determined by review of pathology materials and hospital records. Data were collected using in-person structured interviews. Associations with obesity, measured by body mass index (BMI), were estimated by odds ratios (ORs). All ORs were adjusted for geographic location, age, sex, race, cigarette smoking, and proxy response status.

RESULTS

The ORs for esophageal adenocarcinoma rose with increasing adult BMI. The magnitude of association with BMI was greater among the younger age groups and among nonsmokers. The ORs for gastric cardia adenocarcinoma rose moderately with increasing BMI. Adult BMI was not associated with risk of esophageal squamous cell carcinoma or noncardia gastric adenocarcinoma.

CONCLUSIONS

Increasing prevalence of obesity in the United States population may have contributed to the upward trends in esophageal and gastric cardia adenocarcinomas.

Effects of insulin-like growth factor I on glucose metabolism in rats with liver cirrhosis

To determine the effect of insulin-like growth factor I (IGF-I) on glucose metabolism in cirrhosis, a 2-h euglycemic clamp with IGF-I (0.65 nmol.kg-1.min-1) or insulin (12 pmol.kg-1.min-1) was performed in awake rats with carbon tetrachloride-induced liver cirrhosis. Rates of [3-3H]glucose-determined whole body glucose turnover were similar in the fasting state in cirrhotic and control rats (36.4 +/- 2.6 and 37.7 +/- 2.8 mumol.kg-1.min-1, respectively). In the control group, IGF-I and insulin had similar effects on turnover (81.6 +/- 27.0 and 76.1 +/- 9.9 mumol.kg-1.min-1), muscle glycogen synthesis (47.5 +/- 12.3 and 37.5 +/- 2.5 nmol.g muscle-1.min-1), and suppression of endogenous glucose production (EGP; -54 +/- 14 and -60 +/- 12%). Cirrhotic rats were markedly insulin resistant, reflected by a 43% reduction of turnover (43.8 +/- 9.4 mumol.g muscle-1.min-1; P = 0.03), a 73% reduction in muscle glycogen synthesis (10.2 +/- 3.4 nmol.g muscle-1.min-1; P < 0.0001), and a diminished suppression of EGP (-32 +/- 17% vs. control: -56 +/- 14%; P < 0.05). In contrast, during the IGF-I clamps, turnover increased threefold in the cirrhotic rats (P = 0.001), rates of muscle glycogen synthesis were 7.4 times higher than during the insulin stimulation (P < 0.0001), and EGP was suppressed by 80 +/- 12% (P < 0.05). In conclusion, insulin resistance in cirrhotic rats is mostly due to defects in insulin-stimulated muscle glycogen synthesis, and the ability of IGF-I to stimulate muscle glycogen synthesis as well as suppress EGP is maintained in cirrhotic rats. These findings suggest that alterations in both hepatic and peripheral glucose metabolism in patients with cirrhosis might be amenable to IGF-I therapy.

Mononuclear phagocyte hydrolytic enzyme activity associated with cerebral HIV-1 infection

In patients with HIV encephalitis, activated macrophages and microglial cells in the brain are infected by the human immunodeficiency virus (HIV-1). Immune activation can release neurotoxic chemicals including cytokines, free radicals, autocoids, and hydrolytic enzymes. In this study, the presence of hydrolytic enzymes in acquired immune deficiency syndrome (AIDS)-related neurodegeneration was addressed. Activities of four lysosomal hydrolases were assayed in the frontal lobe of 69 males who died with AIDS and 31 age-matched control men. Activities of all four enzymes were increased significantly (1.6 to 3.6 times) in white matter of patients with AIDS. Less pronounced increases were present in cerebral cortex. Of 69 of the subjects with AIDS, 50 (72%), had at least one abnormally active enzyme. Patients with HIV encephalitis and other neuropathological changes were affected as were many subjects without any clear neuropathological anomaly. Lysosomal cathepsin D immunostaining revealed increased lysosomes within perivascular macrophages, multinucleated cells, activated microglial cells, and hypertrophic astrocytes. Increased enzyme activity was correlated significantly with assay results for HIV-1 DNA using the polymerase chain reaction. The release of acid hydrolases associated with cerebral HIV-1 infection could lead to unopposed hydrolysis of matrix and surface proteins. These post-translational disturbances could contribute to white matter and synaptic injury in AIDS.

Mechanism of inhibition of Na+-glucose cotransport in the chronically inflamed rabbit ileum

In a rabbit model of chronic ileal inflammation, we previously demonstrated that coupled NaCl absorption was reduced because of an inhibition of Cl-/HCO3- but not Na+/H+ exchange on the brush-border membrane (BBM) of villus cells. In this study we determined the alterations in Na+-stimulated glucose [Na+-O-methyl-D-glucose (Na+-OMG)] absorption during chronic ileitis. Na+-OMG uptake was reduced in villus cells from the chronically inflamed ileum. Na+-K+-adenosinetriphosphatase (ATPase), which provides the favorable Na+ gradient for this cotransporter in intact cells, was found to be reduced also. However, in villus cell BBM vesicles from the inflamed ileum Na+-OMG uptake was reduced as well, suggesting an effect at the level of the cotransporter itself. Kinetic studies demonstrated that Na+-OMG uptake in the inflamed ileum was inhibited by a decrease in the maximal rate of uptake for OMG without a change in the affinity. Analysis of steady-state mRNA and immunoreactive protein levels of this cotransporter demonstrates reduced expression. Thus Na+-glucose cotransport was inhibited in the chronically inflamed ileum, and the inhibition was secondary to a decrease in the number of cotransporters and not solely secondary to an inhibition of Na+-K--ATPase or altered affinity for glucose.

Tobacco, alcohol, and socioeconomic status and adenocarcinomas of the esophagus and gastric cardia

BACKGROUND

Incidence rates for adenocarcinomas of the esophagus and gastric cardia have risen steeply over the last few decades. To determine risk factors for these tumors, we conducted a multicenter, population-based, case-control study.

METHODS

The study included 554 subjects newly diagnosed with esophageal or gastric cardia adenocarcinomas, 589 subjects newly diagnosed with esophageal squamous cell carcinoma or other gastric adenocarcinomas, and 695 control subjects. Estimates of risk (odds ratios [ORs] and corresponding 95% confidence intervals [CIs]) were calculated for the four tumor types separately and for esophageal and gastric cardia adenocarcinomas combined.

RESULTS

Risk of esophageal and gastric cardia adenocarcinomas combined was increased among current cigarette smokers (OR = 2.4; 95% = 1.7-3.4), with little reduction observed until 30 years after smoking cessation; this risk rose with increasing intensity and duration of smoking. Risk of these tumors was not related to beer (OR = 0.8; 95% CI = 0.6-1.1) or liquor (OR = 1.1; 95% CI = 0.8-1.4) consumption, but it was reduced for drinking wine (OR = 0.6; 95% CI = 0.5-0.8). Similar ORs were obtained for the development of noncardia gastric adenocarcinomas in relation to tobacco and alcohol use, but higher ORs were obtained for the development of esophageal squamous cell carcinomas. For all four tumor types, risks were higher among those with low income or education.

CONCLUSIONS

Smoking is a major risk factor for esophageal and gastric cardia adenocarcinomas, accounting for approximately 40% of cases.

IMPLICATIONS

Because of the long lag time before risk of these tumors is reduced among ex-smokers, smoking may affect early stage carcinogenesis. The increase in smoking prevalence during the first two thirds of this century may be reflected in the rising incidence of these tumors in the past few decades among older individuals. The recent decrease in smoking may not yet have had an impact.

Partially purified soy hydrolysates retard proliferation and inhibit bacterial translocation in cultured C2BBe cells

Hydrolyzed soybean isolates SP-A and SP-B (Abbott Laboratories, OH), developed for use in enteral nutritional products, were tested in cultures of C2BBe cells, a colonic adenocarcinoma cell line with enterocytic differentiation, to evaluate effects on cell growth, maturation and ability to resist infection by enteric bacteria. SP-A delayed formation of confluent monolayers by 10 d compared with cells cultured without SP-A. SP-A also caused a retardation in the development of intercellular tight junctions as measured by transmonolayer electrical resistance (TER). SP-B had no effect on cell proliferation or TER of intestinal cell cultures. SP-A and SP-B enhanced the development of the brush border enzymes alkaline phosphatase and isomaltase over a 28 d period. By these criteria, SP-A and SP-B appear to affect intestinal epithelial cell development in culture. When C2BBe monolayers were exposed to the enteric bacteria, Salmonella typhimurium or Salmonella typhi, an inhibition of the passage of S. typhi was seen in cultures with SP-A and SP-B. No effect on the passage of S. typhimurium was seen with either soy isolate. Partially purified soy isolates therefore impart resistance to selected enteroinvasive bacteria. Addition of soy hydrolysates to the media of cultured intestinal cells may serve as a rapid and economical screening mechanism for preclinical trials that would test the therapeutic benefits of soybean isolates.

Mucosal inflammation in pediatric diversion colitis: a quantitative analysis

BACKGROUND

Diversion colitis commonly occurs in bypassed segments of colorectum, and has been described qualitatively in Hirschsprung's disease patients with colostomies. The objective of this study was to characterize quantitatively the changes in the inflammatory cell population in the mucosa of children with diversion colitis.

METHODS

Paraffin blocks of well-oriented, full-thickness colorectal tissues were obtained from 15 children with diversion colitis (all with Hirschsprung's disease), four pediatric controls and four adult controls. Sections were immunostained for B and T lymphocytes, macrophages, IgG, IgM, and IgA. Measurements were made referent to a standard length of muscularis mucosae. Lymphoid follicles were counted and the areas occupied by B and T cells were determined by image analysis. Cells in the interfollicular lamina propria were counted separately, but IgA-containing plasma cells were too abundant to enumerate.

RESULTS

Pediatric diversion colitis was characterized by enlarged and more numerous lymphoid follicles with approximately four times as many B lymphocytes and twice as many T lymphocytes in the follicular compartment of the mucosa when compared to pediatric controls. The interfollicular mucosa was thickened (499 +/- 27 versus 380 +/- 56 microns) and contained approximately six times as many B cells and eight times as many T cells as controls. Macrophages and plasma cells containing IgG and IgM were not significantly increased.

CONCLUSIONS

These findings extend the qualitative observations of increased follicular and lamina propria lymphoid tissue in bypassed segments of colon, and are consistent with the hypothesis of persistent antigenic stimulation of the mucosa-associated lymphoid tissue.

Viral RNA in duodenal bile of cirrhotic patients with chronic hepatitis C

BACKGROUND

Hepatitis C virus (HCV) has been detected in blood, saliva, urine, semen, breast milk, and tears. To our knowledge, bile has not yet been investigated. We observed histologic immunoreactivity in bile with an antibody to c100 protein in four of five HCV-positive cirrhotic livers, but also in two HCV-negative controls owing to a focally present cross-reacting antigen.

METHODS

We collected duodenal bile from 13 cirrhotic patients during endoscopic evaluation of varices (10 HCV, three controls) and assayed for HCV by reverse transcriptase polymerase chain reaction.

RESULTS

Viral RNA was detected in the bile of 8 of 10 seropositive patients and in 0 of 3 seronegative controls.

CONCLUSION

Hepatitis C virus RNA and an antigen immunoreactive with anti-c100 protein are present in bile in a proportion of cirrhotic patients with chronic HCV. It remains to be determined whether the virus is intact or degenerate, and whether it is shed into bile from hepatocytes or is a contaminant from blood or other secretions.

Diffuse pagetoid squamous cell carcinoma in situ of the esophagus: a case report

BACKGROUND

In Western countries, esophageal squamous cell carcinoma is usually advanced at presentation and is rarely diagnosed in situ. The authors studied an in situ squamous cell carcinoma that occupied the entire mucosa of a 9 cm length of esophagus, causing dysphagia for solid food in a woman aged 68 years.

METHODS

The esophagectomy specimen contained a circumferential region of depressed tan mucosa in the middle and lower thirds, bordered above and below by normal squamous mucosa, without ulcer, stricture, or mass. The entire lesion was submitted for histology and evaluated with immunostains for cytokeratins and markers of Paget's cells, p53 mutation, and proliferation.

RESULTS

The lesion involved 45 cm2 of mucosa. Large, atypical cells with frequent mitoses occupied the basal layers of the squamous epithelium and were often separated from more superficial maturing cells by acantholysis. Pagetoid spread of tumor cells into nonneoplastic surface and gland duct epithelium was prominent. The tumor cells expressed cytokeratins of low molecular weight, p53 gene product, and proliferating cell nuclear antigen (PCNA), but lacked markers usually seen in Paget's cells in the breast or vulva. No invasion was evident.

CONCLUSIONS

This extensive in situ squamous cell carcinoma of the esophagus resulted from pagetoid spread of tumor cells. These cells had a phenotype suggestive of origin from primitive epidermal stem cells and also had overexpressed p53 and PCNA, but they lacked the capacity to penetrate the basement membrane. Flat, erythematous areas of esophageal mucosa seen during endoscopy could represent early squamous cell carcinoma and should be biopsied.

Effect of chronic inflammation on electrolyte transport in rabbit ileal villus and crypt cells

The effect of chronic inflammation on electrolyte transport in rabbit ileal villus and crypt cells was determined with the use of a rabbit model of chronic ileitis. In both cells, Na+/H+ exchange was monitored by following recovery from an acid load, and Cl-/HCO3- exchange was monitored by following recovery from an alkaline load. In villus cells, recovery from an acid load was not affected; however, recovery from an alkaline load was slowed. These data suggest that chronic inflammation inhibits Cl-/HCO3- exchange in villus cells. In contrast, in crypt cells, recovery from an alkaline load was unaffected, whereas recovery from an acid load was accelerated. These data suggest that chronic inflammation stimulates Na+/H+ exchange in crypt cells. Inhibition of Cl-/HCO3- exchange in villus cells would be expected to inhibit coupled NaCl absorption, which occurs by the coupling of brush-border membrane (BBM) Na+/H+ and Cl-/HCO3- exchange. Stimulation of Na+/H+ exchange in crypt cells, known to be present only on the basolateral membrane, alkalinizes the cell. This alkalinization may stimulate BBM Cl-/HCO3- exchange, resulting in HCO3- secretion. Thus these unique alterations in transporter activity suggest that different endogenous immune-inflammatory mediators may have differing effects on specific transporters in villus and crypt cells in the chronically inflamed ileum.

Cathepsin D in intestinal ganglion cells. A potential aid to diagnosis in suspected Hirschsprung's disease

There is still a need for a better method of detecting immature ganglion cells in paraffin sections of colorectal luminal biopsies in cases suspected of Hirschsprung's disease. The lysosomal aspartic proteinase cathepsin D has been immunolocalized to various cell types, including ganglion cells. We investigated its expression in intestinal ganglion cells to determine whether it could be used as an aid in the detection of immature ganglion cells in rectal biopsies from children suspected of having Hirschsprung's disease. Routinely processed tissues of eight adult intestines resected for gunshot wounds and six ganglioneuromas (for mature ganglion cells), of six colons resected for neonatal necrotizing enterocolitis (for immature ganglion cells), and of 11 cases of suspected and three cases of known Hirschsprung's disease were immunostained with a polyclonal antibody to cathepsin D using the avidin-biotin-peroxidase method. In all cases, all ganglion cell bodies present showed intense granular cytoplasmic reactivity for cathepsin D. The granules crowded the cytoplasm and formed a collarette around the nucleus. In the submucosa, the only other immunoreactive cells were histiocytes, but they could be distinguished from ganglion cells by their characteristic nuclear features and their occurrence singly and unassociated with nerves. The three resection specimens with Hirschsprung's disease showed a clear transition between the ganglionic and the aganglionic segments. We conclude that cathepsin D is a promising marker of immature ganglion cells in cases suspected of Hirschsprung's disease.

Supernatant from cultured intestinal cells inhibits the growth of gram-negative bacteria

Bacterial growth chambers of Transwell units bearing intestinal epithelial monolayers (C2BBe) was consistently observed to be stagnant during the course of transmigration studies with Salmonella typhi. This limitation could not be explained by varying the bacterial load in the inoculum. Conditioned media produced by cultured C2BBe cells would not support bacterial growth. Growth support of the media was restored by heating to 95 C for 10 min. C2BBe conditioned media had bacteriostatic activity for a large variety of gram-negative, enteropathogenic bacteria but had no effect on gram-positive bacteria.

Colonic xanthelasma due to glyceride accumulation associated with an adenoma

The case is reported of a 66-year-old woman who presented with endoscopic and histological features of multiple lipid deposits in the mucosa of the sigmoid colon associated with an adenoma. Associated clinical features were abdominal pain and diarrhea. Colectomy led to the complete resolution of symptoms. Biochemical analysis disclosed the presence of glycerides in the mucosa. The pathogenesis of lipid deposits and the possible link with the formation of an adenoma is discussed.

Encephalitozoon (Septata) intestinalis: cytologic, histologic, and electron microscopic features of a systemic intestinal pathogen

Encephalitozoon (Septata) intestinalis affects AIDS patients with CD4 counts <100/microL, causing intestinal and disseminated disease. It must be distinguished from the more common intestinal microsporidian, Enterocytozoon bieneusi, and from other microsporidia of extraintestinal tissues, such as Encephalitozoon hellem and E cuniculi, because clinical manifestations and treatment differ. In this report, the authors describe the diagnostic features of E intestinalis and illustrate all stages of its life cycle as exemplified by a case studied in detail. Spores can be detected by light microscopy in feces, urine, or nasal secretions, but not identified to species. A presumptive tissue diagnosis of E intestinalis can be made if 20 to 50 organisms 1.2-2.5 microm in diameter are seen within vacuoles in enterocytes. The diagnosis is substantiated if organisms also are present in stromal cells. On electron microscopy, the septate parasitophorous vacuole is pathognomonic. E bieneusi occurs only in intestinal and biliary epithelial cells, and never within a vacuole. E hellem and E cuniculi, which are not intestinal pathogens, may cause systemic infection but develop in a nonseptate vacuole.

Hepatomegaly and abnormal liver tests due to glycogenosis in adults with diabetes

In adults with diabetes mellitus, hepatomegaly and abnormalities of liver enzymes occur as a consequence of hepatocellular glycogen accumulation, as has been well described in children. During periods of hyperglycemia glucose freely enters the hepatocytes driving glycogen synthesis, which is augmented further by administration of insulin to supraphysiologic levels. The accumulation of excessive amounts of glycogen in the hepatocytes is a function of intermittent episodes of hyperglycemia and hypoglycemia and the use of excessive insulin. Hepatic glycogenosis occurs in patients with poorly controlled insulin-dependent type I or type II diabetes. The clinical manifestations of this phenomenon may include abdominal pain and obstructive symptoms such as early satiety, nausea, and vomiting. Ascites has rarely been reported. The typical biochemical findings are mildly to moderately elevated aminotransferases, with or without mild elevations of alkaline phosphatase. Liver synthetic function is usually normal. All these abnormalities, including the hepatomegaly, are readily reversible with sustained euglycemic control. The other major cause of hepatomegaly in patients with diabetes is steatosis. This is a function of the body habitus and state of insulin resistance rather than glycemic control. However, the distinction between steatosis and glycogenosis is important: whereas steatosis may progress to fibrosis and cirrhosis, glycogenosis does not, but reflects the need for better diabetic control. Glycogenosis and steatosis cannot be distinguished reliably on ultrasound examination. The histology, however, is definitive. In glycogenosis, as in primary glycogen storage diseases, there is excess glycogen in the cytoplasm, and often also in the nucleus, of hepatocytes. The hepatocytes throughout the lobule appear pale and swollen with clearly defined cell boundaries. Ultrastructural examination reveals cytoplasmic glycogen in clumps displacing organelles to the periphery of the cell, and there is little if any steatosis. We have shown that hepatomegaly due to glycogenosis in adults with diabetes is similar in all respects to the condition seen in children. As in children, liver enzyme abnormalities are unreliable in predicting the presence or the extent of glycogenosis. Hepatic glycogenosis can occur at any age, and therefore should be included in the differential diagnosis of hepatomegaly in all insulin-requiring diabetics.

Migration of Salmonella typhi through intestinal epithelial monolayers: an in vitro study

This study characterizes the transmigration of enteroinvasive Salmonella typhi in vitro, using a human intestinal epithelial cell line as a model of small intestinal epithelium. C2BBe cells, a subclone of CACO-2 with a highly differentiated enterocytic phenotype, were grown to maturity on Transwell filters. S. typhi Ty2 and the vaccine strain, Ty21a, the S. typhi mutant X7344 and parent strain SB130, and S. typhimurium 5771 in logarithmic phase were introduced to the upper chamber of the filter units. Numbers of bacteria in the lower chamber, TER and permeability of the monolayer to mannitol were measured over time. Monolayers were examined by light, electron and confocal microscopy to determine the pathway of bacterial transmigration, and intracellular bacteria were estimated by gentamicin assay. Epithelial cell injury was quantified by light microscopy. S. typhi transmigrated earlier and in larger numbers than S. typhimurium, inducing marked changes in electrical resistance and permeability. Unlike S. typhimurium, S. typhi selected epithelial cells in small number and caused their death and extrusion from the monolayers leaving holes through which S. typhi transmigrated. Ty2 consistently transmigrated in larger numbers and with more injury to monolayers than Ty21a. S. typhi crosses the monolayers of C2BBe cells by a paracellular route in contrast to the transcellular pathway described for other Salmonellae. This may be related to the unique pathophysiology of S. typhi infection and the restricted host specificity of this pathogen. In these assays the vaccine strain, Ty21a, is slightly less invasive than its parent, though more invasive than S. typhimurium.

T-cell alpha beta + and gamma delta + deficient mice display abnormal but distinct phenotypes toward a natural, widespread infection of the intestinal epithelium

Vertebrate immune systems contain T cells bearing either alpha beta or gamma delta T-cell antigen receptors (TCRs). alpha beta T cells perform all well-characterized T-cell effector functions, while the biological functions of gamma delta + cells remain unclear. Of particular interest is the role of gamma delta + cells during epithelial infections, since gamma delta + cells are commonly abundant within epithelia. Eimeria spp. are intracellular protozoa that infect epithelia of most vertebrates, causing coccidiosis. This study shows that in response to Eimeria vermiformis, mice lacking alpha beta T cells display defects in protective immunity, while mice lacking gamma delta + cells display exaggerated intestinal damage, apparently due to a failure to regulate the consequences of the alpha beta T cell response. An immuno-downregulatory role during infection, and during autoimmune disease, may be a general one for gamma delta + cells.

Mucosal biopsy findings and venous abnormalities in idiopathic myointimal hyperplasia of the mesenteric veins

Idiopathic myointimal hyperplasia of the mesenteric veins (IMHMV) is a rare cause of intestinal ischemia secondary to venous compromise. A patient with this condition who presented with crampy abdominal pain, diarrhea, and rectal bleeding initially attributed to inflammatory bowel disease had several colonoscopies and ultimately a sigmoid colectomy. The colonic mucosa in biopsies performed at initial presentation and subsequently and in the resection specimen contained numerous hyperplastic, thick-walled, hyalinized vessels in the lamina propria, which have not been described in this entity previously. Examination of the mucosa in 27 resection specimens of ischemic enterocolitis of various etiologies, in five resections of prolapsed rectum, and in seven colostomy specimens revealed no instance in which there were similar histologic abnormalities. When seen on biopsy, therefore, these features should lead to inclusion of IMHMV in the differential diagnosis. Furthermore, the characteristic lesions of the submucosal and extramural veins in IMHMV were compared with those of 14 examples, from several organs, of veins subjected to arterial pressure and 21 cases of venous hypertension. The marked similarity of the arterialized veins to the mural veins of IMHMV suggests a role for arteriovenous fistulization in the pathogenesis of IMHMV, and a mechanism by which this might occur is proposed.

Intractable cough and abnormal pulmonary function in benign recurrent intrahepatic cholestasis

Benign recurrent intrahepatic cholestasis (BRIC) is a syndrome characterized by recurrent episodes of cholestasis with associated pruritus. The intensity and duration of cholestatic episodes, and the length of the intervening periods, vary unpredictably. We report the case of a patient with BRIC who was incapacitated by a severe intractable cough that accompanied marked pruritus during her second cholestatic episode. No cause for the cough was found, and it resolved spontaneously with amelioration of mild restrictive abnormalities of pulmonary function as the cholestasis subsided. Although cough has not been recognized as a complication of cholestasis, we postulate that it may occur either (i) as a result of direct stimulation of sensory nerves by circulating humoral substances related to the cholestasis that act either peripherally in the airways or centrally, or (ii) through stimulation of the vagus nerve in the liver, leading to cough that is mediated either centrally or by reflex.

Fluorometric assay for DNA polymerases and reverse transcriptase

We report a quick, easy and inexpensive fluorometric assay that measures the activity of replication enzymes using Pico-GreenTM. The systems tested include replication of the natural template M13 Gori by E. coli DNA polymerase III holoenzyme and the replication of a synthetic homopolymer by human immunodeficiency virus reverse transcriptase. A direct comparison of the fluorometric assay with the conventional isotopic assay shows that the fluorometric assay accurately reflects the extent of replication. By performing the assay reactions directly in 96-well plates and using a fluorescence plate reader to determine the extent of reaction, the time required to measure replication activities is significantly shortened.

False tumor-positive lymph nodes in radioimmunodiagnosis and radioimmunoguided surgery: etiologic mechanisms

We investigated the causes of false-positive (nontumor cell) focal uptake in radioimmunodiagnosis (RAID) and false-positive high counts in radioimmunoguided surgery (RIGS). Tissue blocks of two such RAID cases were recut and examined by immunohistochemistry (IH) (group 1). Lymph nodes in the drainage area of 14 colon cancers selected because of tumor-positive draining nodes were examined similarly (group 2). The lymph nodes in group 1 showed nontumor cell germinal center (GC) and rare macrophage (M phi) positivity with monoclonal antibody (mAb) CC49 to tumor antigen (Ag) TAG-72, the same Ag to which the mAb B72.3, used for the RAID studies, was directed. In group 2, CC49 staining was observed in the colon cancers, in noncellular tumor Ag in lymphatic channels, and in the GC of draining nodes in a pattern similar to that of follicular dendritic cells (FDC). An In-111-mAb/tumor Ag (TAG-72 or CEA) complex can result in false-positive RAID/RIGS studies by In-111 retained in the lysosomes of lymph node M phi, following attachment of the mAb to the Ag, and their catabolism in the M phi. An I-125-mAb to either tumor Ag could lead to false positive RIGS studies due to its attachment to the Ag portion of ag/ab complexes affixed to the FDC in the GC of the lymph nodes draining a tumor.

Noninvasive assessment of hepatic triglyceride content in humans with 13C nuclear magnetic resonance spectroscopy

Hepatic lipid content was assessed noninvasively in 15 patients with hepatic steatosis by 13C nuclear magnetic resonance (NMR) spectroscopy, and compared in a double-blind fashion with histological grading and morphometric quantitation of fat in liver biopsies taken within 2 weeks of the study. The lipid content in the liver biopsies was expressed as the volume fraction of total parenchyma occupied by fat. Hepatic triglyceride content was determined by comparing the 13C NMR signal intensity in vivo with the signal intensity obtained from a lipid phantom of known concentrations. There was an approximately 30-fold increase in the 13C NMR signals of the saturated carbons (methyl/methylene [CH2]n) region of hepatic triglycerides from patients with grade 4 steatosis compared with those with grade 0, yielding a good dynamic range for measuring hepatic triglyceride content. The correlation coefficient between the morphometric and 13C NMR techniques was 0.89 (P < .01). These studies demonstrate that 13C NMR spectroscopy can be used to noninvasively assess hepatic triglyceride content in humans. This method may be clinically useful for diagnosis and follow-up of patients with hepatic steatosis.

Heterotopic bone formation in the gastrointestinal tract

Heterotopic bone is found rarely in the gastrointestinal tract. Here we report four cases, one of which occurred in Barrett's esophagus in an area of metaplasia of specialized cell type without evidence of neoplasia. In the remaining cases, bone was associated with mucin-producing tumors of the appendix, transverse colon, and rectum. The clinical and pathologic findings are discussed in detail. Heterotopic bone formation in the digestive tract usually occurs in the colorectum in association with benign or malignant epithelial tumors, and most often with those that produce abundant mucin. The pathogenesis of the osseous metaplasia in the gastrointestinal tract is not understood, although mucin extravasation is an almost constant feature. Fragments of metaplastic bone in a biopsy of a mucinous neoplasm of the digestive tract should not be misinterpreted as osseous invasion.

Type 73 human papillomavirus in esophageal squamous cell carcinoma: a novel association

BACKGROUND

Human papillomaviruses (HPVs) commonly cause proliferative lesions of squamous epithelia, and infection with certain HPV types carries a high risk of malignant transformation, especially in the uterine cervix but also at other sites, including the esophagus. We used molecular techniques to detect and type HPV in an in situ squamous cell carcinoma in the esophagus of a 39-year old woman.

METHODS

DNA was extracted from paraffin sections of the esophageal lesion and of the uterine cervix (which was removed several years earlier), and analyzed for HPV by polymerase chain reaction (PCR). Primers complementary to highly conserved regions of the open reading frame of most genital HPVs were used to amplify a approximately 450 base pair product that contained both conserved and divergent regions. The PCR products were hybridized with probes specific for HPV-6, HPV-11, HPV-16, and HPV-18, and with a consensus probe. A conspicuous band in the esophageal sample failed to hybridize with any of the probes. The amplimer was subcloned and sequenced. The sequence was compared with other known HPVs.

RESULTS

The intraepithelial neoplasia in the patient's cervical cone biopsy contained HPV-16. The esophageal lesion contained HPV that did not hybridize with probes for types 6, 11, 16, or 18, but exhibited 98.3% homology with HPV-73.

CONCLUSIONS

Squamous cell carcinoma in situ of the esophagus may be associated with infection by HPV-73.

Genetic ablation of parietal cells in transgenic mice: a new model for analyzing cell lineage relationships in the gastric mucosa

The gastric mucosa of mammalian stomach contains several differentiated cell types specialized for the secretion of acid, digestive enzymes, mucus, and hormones. Understanding whether each of these cell lineages is derived from a common stem cell has been a challenging problem. We have used a genetic approach to analyze the ontogeny of progenitor cells within mouse stomach. Herpes simplex virus 1 thymidine kinase was targeted to parietal cells within the gastric mucosa of transgenic mice, and parietal cells were ablated by treatment of animals with the antiherpetic drug ganciclovir. Ganciclovir treatment produced complete ablation of parietal cells, dissolution of gastric glands, and loss of chief and mucus-producing cells. Termination of drug treatment led to the reemergence of all major gastric epithelial cell types and restoration of glandular architecture. Our results imply the existence of a pluripotent stem cell for the gastric mucosa. Parietal cell ablation should provide a model for analyzing cell lineage relationships within the stomach as well as mechanisms underlying gastric injury and repair.

Characterization of RNA with unusual electrophoretic mobility from tissues of patients with Crohn's disease

RNAs from tissues of patients with Crohn's disease that migrate off the diagonal in a two-dimensional gel electrophoresis system were partially characterized. One of the RNA species was a discrete cleavage product of region V2-9 of 28S rRNA; another is a conformer or variant of 5.8S rRNA; and a third is a mixture of unidentified fragments with mobility similar to that of 7S RNA. The yield of these species from resected tissue and their visualization by silver staining was very sensitive to the details of the preparative procedure. No evidence of viroid-like RNA was found within the range of molecular sizes (< 7S) that we examined.

The relationship of granulomas to blood vessels in intestinal Crohn's disease

It has been suggested that granulomatous vasculitis is a primary mechanism in the production of pathologic changes seen in Crohn's disease. We set out to investigate the relationship of granulomas to blood vessels and to confirm or refute previous reports of granulomatous vasculitis in Crohn's disease. Thirty paraffin embedded tissues from 11 patients with Crohn's disease were selected after examination of H&E stained sections for the presence of granulomas. Using an immunohistochemical method, various monoclonal antibodies were applied to sequential sections from each tissue to demonstrate vascular structures and granulomas. In three patients none of the granulomas occurred in association with blood vessels, in five a small proportion of the granulomas affected blood vessels, and in three granulomatous vasculitis appeared occlusive and significant. A total of 232 granulomas were identified, 22% of which were closely associated with blood vessels, which included both arteries and veins; 16% were perivascular, while 6% were intravascular. Perivascular granulomas did not surround blood vessels or invade the medial layers. They were asymmetric, suggesting that they originated by encroachment of nearby lymphatic or connective tissue granulomas. These results indicate that the granulomas of Crohn's disease are usually not associated with blood vessels; however, there is a minority of patients in whom vascular granulomatous inflammation may be important, although probably as a secondary phenomenon.

Relationship of aminotransferases to liver histological status in chronic hepatitis C

OBJECTIVES

Serum aminotransferase levels characteristically fluctuate in chronic hepatitis C, but their relationship to grade (i.e., inflammatory activity) and stage (i.e., degree of fibrosis) of liver disease is uncertain. We therefore correlated aminotransferase levels and liver biopsy findings in 90 patients with serologically confirmed chronic hepatitis C.

METHODS

Mode of transmission; disease duration; symptoms and signs of liver disease; alcohol intake; autoantibody, HIV, and hepatitis B virus status; and liver biochemistries were obtained from records. Liver biopsies were 1) given a morphological diagnosis, 2) evaluated for features of chronic hepatitis C, and 3) scored with a histological activity index.

RESULTS

Individual aminotransferase levels were not related to clinical or laboratory variables, nor were they reliably predictive of morphological diagnosis. No histological characteristics were associated with a particular range of aminotransferase values, except aminotransferases > 350 U/L, which were associated with piecemeal necrosis. Although mean values of aminotransferases were significantly lower among patients with chronic persistent hepatitis (CPH) (i.e., with minimal activity) compared with chronic active hepatitis (CAH) (mild to moderate activity) (ALT 110 U/L +/- 71 SD vs 256 +/- 211; AST 57 U/L +/- 34 vs 123 +/- 88) and in the absence of piecemeal necrosis compared with in its presence (ALT 133 +/- 84 vs 207 +/- 149; AST 73 +/- 47 vs 120 +/- 83), overlap of values was considerable between different histological groups.

CONCLUSION

Aminotransferases do not predict liver histological status in chronic hepatitis C, although > or = 10-fold elevations suggest that piecemeal necrosis is present.