PubMed Health⌕ Search

Biomedical subjects

N Harpaz

Publications and source records attributed to N Harpaz.

At least 37 records · Page 2Linked to original sources
PubMed1996

Collagenous gastritis associated with lymphocytic colitis.

Collagenous sprue and collagenous colitis are two well-recognized idiopathic enteritides whose defining histologic attribute is fibrous thickening of the subepithelial basement membrane. Analogous changes in gastric mucosa seem to be quite rare. The term "collagenous gastritis" was recently applied for the first time to an isolated case of refractory gastritis in which distinctive subepithelial gastric fibrosis was noted. We report an additional case of this entity in a 35-year-old woman with refractory dyspepsia. In contrast to the earlier case of collagenous gastritis, our patient also had lymphocytic colitis, a type of colitis associated with watery diarrhea. Collagenous gastritis appears to be a distinct clinicopathologic entity, the histologic changes of which should be sought in patients with unexplained dyspepsia. Increased awareness of this condition and its possible clinical correlates may provide clues to its etiology and pathogenesis.

Adult↗
PubMed1996

Colorectal cancer in idiopathic inflammatory bowel disease.

The development of colorectal cancer is the most serious long-term problem faced by patients with extensive ulcerative colitis and Crohn's colitis, with an incidence 20-fold higher and an average age of onset 20 years younger than colorectal cancer in the general population. This report summarizes the epidemiology, pathology, and recent advances in the molecular pathogenesis of colorectal cancer in inflammatory bowel disease and of its acknowledged precursor, mucosal dysplasia. It also reviews the rationale behind the use of endoscopic surveillance for dysplasia as a means of reducing cancer mortality, as well as some of the issues involved in its effective implementation.

Adenocarcinoma↗
PubMed1996

Alterations of transforming growth factor-beta 1 receptor type II occur in ulcerative colitis-associated carcinomas, sporadic colorectal neoplasms, and esophageal carcinomas, but not in gastric neoplasms.

BACKGROUND & AIMS: Gastric cancers, sporadic colorectal cancers, and ulcerative colitis (UC)-associated colorectal carcinomas and dysplasias manifest microsatellite instability (MI); however, esophageal carcinomas rarely exhibit MI. Recently, a transforming growth factor-beta 1 type II receptor (TGF-beta 1RII) mutation in a coding microsatellite was described in primary colorectal carcinomas demonstrating MI. No previous studies of TGF-beta 1RII have addressed mechanisms of inactivation other than MI in human tumors; furthermore, MI-negative tumors have not been examined for TGF-beta 1RII mutation. We evaluated 138 primary human neoplasms for mutation in the poly-A microsatellite tract of TGF-beta 1RII. Additionally, a group of esophageal tumors was evaluated for the expression of TGF-beta 1RII messenger RNA (mRNA). METHODS: First, we determined whether MI was present at other chromosomal loci in these lesions. The poly-deoxyadenine (poly-A) microsatellite tract within the TGF-beta 1RII coding region was then PCR-amplified. In a group of MI-negative esophageal tumors, RT-PCR was performed to determine the expression of TGF-beta 1RII mRNA. RESULTS: Among 17 MI+ UC specimens, 3 (18%) demonstrated TGF-beta 1RII poly-A tract mutation (2 cancers and 1 dysplasia), while 2 (4%) of 44 MI-negative UC specimens (1 dysplasia and 1 tumor), and 13 (81%) of 16 MI+ sporadic colorectal cancers, contained TGF-beta 1RII poly-A mutation. No gastric or esophageal tumors contained TGF-beta 1RII mutation. Among 21 MI-negative esophageal carcinomas. 6 cases (28.5%) had TGF-beta 1RII transcripts that were low or undetectable by RT-PCR. CONCLUSIONS: Mutation within the poly-A microsatellite tract of TGF-beta 1RII occurs early in a subset of UC-neoplasms and commonly in sporadic colorectal cancers, but may be rare in MI+ gastric tumors. Diminished expression of TGF-beta 1RII mRNA in esophageal tumors suggests that mechanisms of inactivation in this gene other than MI play a role in esophageal carcinogenesis.

Colitis, Ulcerative↗
PubMed1995

Adenomatous polyposis coli gene mutations in ulcerative colitis-associated dysplasias and cancers versus sporadic colon neoplasms.

Adenomatous polyposis coli (APC) gene mutations occur in most sporadic colonic adenomas and carcinomas. Precursor lesions of ulcerative colitis (UC)-associated colon carcinomas, although morphologically similar to sporadic adenomas, may be biologically distinct from them and are, in fact, managed differently. Since sporadic adenomas may also occur in UC, a method of discriminating between these forms of neoplasia could have clinical utility. We examined 33 patients with UC-associated dysplasias and cancers and 23 sporadic colon neoplasms in a side-by-side comparison for APC mutations. Codons 686-1693, containing 64% of all reported APC mutations (the mutation cluster region), were screened for truncating mutations using an in vitro synthesized protein assay. Two of thirty-three patients (6%) with UC-associated dysplasias and cancers had a total of three truncating APC mutations, all in frank carcinomas, while 17 of 23 (74%) with sporadic colonic neoplasms had mutations. DNA sequencing confirmed two mutations in codon 1460, replacing arginine with a stop codon, as well as one 2-base pair deletion, resulting in a frameshift and a stop at codon 1477. One specimen contained one each of these APC mutations. This apparent contrast in mutation rates at the mutation cluster region of APC is consistent with other biological characteristics separating sporadic colon neoplasms from UC-associated dysplasias and cancers. These data raise the possibility that nonadenomatous UC dysplasias may arise by a molecular pathway distinct from that prevailing in sporadic colon carcinogenesis, and they suggest a molecular assay to discriminate between sporadic adenomas and dysplasias occurring in UC.

Base Sequence↗
PubMed1995

Perinuclear anti-neutrophil cytoplasmic antibody and refractory pouchitis. A case-control study.

Refractory pouchitis (RP) is a debilitating complication of ileal pouch reservoirs that affects approximately 2.5% of patients. Although the cause of RP is unknown, it is frequently hypothesized that it reflects underlying Crohn's disease. Since perinuclear anti-neutrophil cytoplasmic antibody (pANCA) is found in approximately 70% of ulcerative colitis patients but only rarely in Crohn's disease patients, it may help distinguish Crohn's disease from ulcerative colitis. Therefore, to test whether RP reflects "missed" Crohn's disease, we determined the ANCA status of 26 patients with RP. The pANCA was positive in 42% of cases [50% of Kock pouch cases and 33% of ileoanal pull-through (IAPT) cases] and 57% of matched control subjects without pouchitis (N = 42, P = NS). Moreover, 3/6 (50%) of IAPT RP subjects whose signs and symptoms most suggested Crohn's disease tested positive for pANCA. When compared to controls, IAPT cases exhibited significantly more preoperative extraintestinal manifestations (EIMs) of inflammatory bowel disease (P < 0.05). The presence of preoperative EIMs was 100% predictive of postoperative EIMs (P < 0.05). Review of pouch biopsies from cases of RP revealed no pathognomonic histologic features of Crohn's disease. These data confirm our previous suggestion that RP does not reflect underlying Crohn's disease but may be associated with the EIMs of inflammatory bowel disease.

Adult↗
PubMed1995

Urinary organ specific neoantigen. A potentially diagnostic test for colorectal cancer.

Urinary organ-specific neoantigen from colorectal cancer patients has been used to make a monoclonal antibody, BAC 18.1. In this study we assessed the potential of this antibody for the diagnosis of colorectal cancer. We evaluated binding in both urine and effluent samples and compared it with effluent carcinoembryonic antigen standardized for both volume (nanograms per milliliter) and protein. Urinary organ-specific antigen as detected by BAC 18.1 was significantly greater in 29 cancer patients (A405: 0.717 +/- 0.500) vs 27 controls [0.121 +/- 0.273 (P < 0.05)]. Considerable overlap of binding of BAC 18.1 was observed in the colonic effluent of patients with CRC (N = 13), adenomas (N = 26), inflammatory bowel disease (N = 8), or having a normal colonoscopic examination (N = 24). CEA levels (nanograms per milliliter) were significantly elevated in the effluent samples of patients with a past history of colorectal cancer, as compared to that of normal individuals (P < 0.05). The presence of the M(r) 30,000 organ-specific neoantigen in colonic effluent was also demonstrated by western blot. Organ-specific neoantigen originates in the colon and is excreted into the urine, so the BAC 18.1 binding levels in the urine may be a diagnostic aid for CRC.

Adult↗
PubMed1995

Sialosyl-Tn antigen: initial report of a new marker of malignant progression in long-standing ulcerative colitis.

BACKGROUND & AIMS: Expression of the mucin-associated carbohydrate antigen sialosyl-Tn (STn) correlates with malignant transformation in sporadic colonic neoplasms. The aim of this study was to analyze STn antigen expression in patients with long-standing ulcerative colitis (UC). METHODS: STn antigen was assessed by immunohistochemistry in archival tissues. Study A was a retrospective chronological case-control study. Serial surveillance colonoscopic biopsy specimens without inflammation or dysplasia were analyzed in 7 patients who developed colon cancer and in 8 controls who did not develop colon cancer. Study B analyzed the anatomic distribution of STn expression in 17 cancer-bearing (case) and 6 cancer-free (control) colectomy specimens from patients with UC. In some colectomy specimens, STn was compared with aneuploidy, which was determined by flow cytometry. RESULTS: In study A, among the 7 patients with UC who developed cancer, 6 patients (86%) expressed STn in at least one prior nondysplastic surveillance biopsy specimen from the same site. Only 3 of 8 control patients (38%) expressed STn. In study B, STn was expressed in 40 of 82 specimens (49%) from cancer-bearing colons but only 8 of 62 specimens (13%) from cancer-free colons. STn was expressed in most aneuploid areas but was also found in diploid, nondysplastic mucosa. CONCLUSIONS: STn antigen seems to be a promising marker of cancer risk in patients with UC.

Aneuploidy↗
PubMed1994

Molecular evidence for two forms of Crohn disease.

Recent epidemiological evidence suggests that there are two forms of Crohn disease (CD): perforating and nonperforating. We hypothesized that, just as with tuberculoid and lepromatous leprosy, differences in the two forms of CD would be both identified and determined by differences in the host immune response. Resected intestinal tissue from control patients as well as perforating and nonperforating CD patients was evaluated for mRNA levels. We employed 32P PCR amplification with published or custom-designed primers of a housekeeping gene (beta-actin); a human T-cell marker (CD3-delta); and the cytokines tumor necrosis factor alpha, transforming growth factor beta, granulocyte/macrophage colony-stimulating factor, interleukin (IL) 1 beta, IL-1ra, and IL-6. Differences were identified with IL-1 beta (control = 162 +/- 57 vs. perforating = 464 +/- 154 vs. nonperforating = 12,582 +/- 4733; P < or = 0.02) and IL-1ra (control = 1337 +/- 622 vs. perforating = 2194 +/- 775 vs. nonperforating = 9715 +/- 2988; P < or = 0.02). These data corroborate the epidemiological observation that there are two forms of CD. Nonperforating CD, the more benign form, is associated with increased IL-1 beta and IL-1ra mRNA expression. We conclude that it is the host immune response that determines which form of CD becomes manifest in any given individual and discuss the investigative, diagnostic, and therapeutic implications of these observations.

Actins↗
PubMed1994

Microsatellite instability in ulcerative colitis-associated colorectal dysplasias and cancers.

Microsatellites are short nucleotide repeat sequences present throughout the human genome. Alterations of microsatellites, comprising extra or missing copies of these sequences, have been termed microsatellite instability. This abnormality occurs in sporadic and hereditary adenocarcinomas of the proximal colon, as well as in many other tumor types. We determined whether microsatellite instability occurred in ulcerative colitis-associated cancers or precancerous dysplasias. Sixty-three patients were evaluated, consisting of 188 samples of genomic DNA (63 normal controls, 68 cancers, 52 dysplasias, and 5 adjacent tissues) at loci D2S119, D2S123, D2S147, D10S197, and D11S904. Multiplex polymerase chain reaction was performed using one radiolabeled nucleotide, and the products were electrophoresed on denaturing polyacrylamide gels. Seventeen of the 63 patients (27%) possessed lesions showing instability at 1 or more loci. Fourteen of 68 tumor samples (21%) and ten of 52 dysplasias (19%) displayed instability. There was no tendency for a greater number of loci to manifest instability in more advanced lesions. Neither anatomic location nor loss of heterozygosity at the p53 locus were associated with microsatellite instability by 2-way table analysis. These data support a role for defective DNA repair in the generation of a subset of both early and advanced ulcerative colitis-associated colorectal neoplastic lesions.

Colitis, Ulcerative↗
PubMed1994

p53 protein expression in ulcerative colitis-associated colorectal dysplasia and carcinoma.

The frequency and timing of p53 inactivation in ulcerative colitis (UC)-associated tumorigenesis were investigated using immunohistochemistry (IHC) to detect p53 protein overexpression in 56 carcinomas and 40 dysplastic epithelia derived from 58 patients with UC undergoing colectomy for neoplasia. p53 DNA in 25 of the carcinomas also was evaluated by single-strand conformation polymorphism analysis (SSCP) to detect point mutations in exons 5-8 and by loss of heterozygosity analysis to detect allelic deletions. Point mutations were detected in 20 of the 25 carcinomas (80.0%) undergoing both IHC and DNA analysis. One carcinoma contained an allelic deletion but no mutations of the corresponding allele within the region tested. p53 overexpression occurred in 16 (76.2%) of the 21 carcinomas with point mutations and/or allelic deletions but not in any of those with wild type DNA. Of the 56 carcinomas evaluated by IHC, p53 overexpression occurred in 34 carcinomas (60.7%). The proportion of positive tumors was independent of stage, anatomic location, differentiation, and histological subtype. Overexpression was observed in nine of 20 dysplastic masses devoid of and situated remote from carcinoma (45.0%) and correlated positively with increasing grade of dysplasia (P < .025). In contrast, overexpression occurred in 16 of 20 dysplastic epithelia situated adjacent to carcinoma (80.0%) and correlated with overexpression by the corresponding carcinomas but not with the grade of dysplasia present (P = .013). It is concluded that p53 overexpression can be detected by IHC in most, although not all, UC-associated carcinomas with p53 mutations and/or allelic deletions. Based on this method, p53 overexpression occurs frequently in UC-associated carcinomas regardless of stage and pathological characteristics, in noncancerous dysplastic masses with high grade dysplasia, and in dysplasias of all grades situated adjacent to carcinomas. These findings implicate p53 inactivation in the progression from dysplasia to carcinoma in UC and suggest that its occurrence in dysplastic epithelium may be an independent marker of malignant potential.

Carcinoma↗
PubMed1994

Clinicopathological characteristics of colorectal carcinoma complicating ulcerative colitis.

This study examined three features associated with colorectal carcinoma complicating ulcerative colitis: (a) the distribution of 157 cancers in 120 patients with ulcerative colitis treated at St Mark's Hospital between 1947 and 1992; (b) the frequency at which dysplasia was found at a distance from the tumour in 50 total proctocolectomy specimens in which an average of 27 histology blocks were reviewed, and (c) the five year survival rate according to Dukes's stage and participation in a surveillance programme. Of 157 carcinomas, 88 (56%) occurred in the rectosigmoid, 19 (12%) in the descending colon or splenic flexure, and 50 (32%) in the proximal colon. Among the 120 patients, the rectum or sigmoid colon contained cancer in 81 (67.5%). Dysplasia was detected in 41 of 50 reviewed proctocolectomy specimens (82%). Dysplasia distant to a malignancy occurred in 37 (74%); two were classified indefinite, probably positive, 19 were low grade, and 16 were high grade; in 18 specimens there was an elevated dysplastic lesion. Survival was related to the Dukes's stage: about 90% of patients with Dukes's A or B cancer were alive at five years. The five year survival of 16 patients in whom cancer developed during surveillance was 87% compared with 55% of 104 patients who did not participate in surveillance (p = 0.024).

Adult↗
PubMed1994

Langerhans cell histiocytosis of the stomach. A cause of granulomatous gastritis and gastric polyposis.

Langerhans cell histiocytosis (LCH) of the alimentary tract is a rare condition, and LCH of the stomach especially so. We report a histologically and endoscopically unusual case of gastric LCH, the diagnosis of which was based on gastric mucosal biopsy specimens from an adolescent with multi-organ LCH and striking gastric polyposis. Microscopically, the gastric mucosa was expanded by discrete granulomatous microaggregates of Langerhans cells, resulting in a close resemblance to other, more common nonnecrotizing granulomatous gastritides. The diagnosis of LCH was confirmed immunohistochemically and ultrastructurally. To our knowledge, this is the first report of gastric LCH with a granulomatous histologic pattern, and the third to cause diffuse gastric polyposis. Langerhans cell histiocytosis should be included in the histologic differential diagnosis of granulomatous gastritis, as well as in the endoscopic differential diagnosis of gastric polyposis.

Adolescent↗
PubMed1994

Ulcerative appendicitis in universal and nonuniversal ulcerative colitis.

Ulcerative appendicitis (UA), the appendiceal counterpart of ulcerative colitis (UC), is frequently present in colectomy specimens from patients with universal UC and is regarded as part of the continuous inflammatory process that is a hallmark of this disease. It has been reported, although not universally accepted, that UA may also occur in UC that spares the proximal colon, constituting a skip lesion. Colectomies, which included appendices, from 160 consecutive adult and pediatric patients with UC were reviewed histologically and separated into two groups, universal and nonuniversal UC, on the basis of a stringent histopathological definition of normal mucosa. Forty-five cases with obliterated appendiceal lumens were excluded. UA was present in 82 of the 94 cases of universal UC (87%), including 75 of the 83 adult cases (90%) and 7 of the 11 pediatric cases (64%). UA was present in 18 of the 21 cases of nonuniversal UC (86%), all of which were adults, representing skip lesions. UA was found in 12 of the 14 cases in which colitis commenced distal to the hepatic flexure, including 2 of the 3 cases of left-sided colitis and 2 of the 2 cases of proctosigmoiditis. Among patients whose clinical indication for colectomy was the presence of dysplasia or carcinoma and who had patent appendices, UA was present in 6 of the 9 cases with universal UC (68%) and in each of the 3 cases with nonuniversal UC (100%). We conclude that in colectomy specimens discontinuous appendiceal involvement in nonuniversal UC is as prevalent as continuous involvement in universal UC.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Resolution of protein-losing hypertrophic lymphocytic gastritis with therapeutic eradication of Helicobacter pylori.

Lymphocytic gastritis (LG) is a recently described histological entity characterized by increased lymphocytes in the superficial gastric epithelium and foveolae. It includes a subgroup of patients with giant gastric folds and, often, a protein-losing state, a condition termed hypertrophic lymphocytic gastritis (HLG). Despite close endoscopic and clinical similarities to classical Menetrier's disease, the histopathological features of these two diseases are sufficiently distinct that they are regarded as separate entities. The etiology and pathogenesis of HLG are unknown, and the possible etiological role of Helicobacter pylori in particular is controversial. For this reason we report the case of a 48-yr-old female with HLG, hypoproteinemia, and H. pylori infection whose disease resolved clinically, endoscopically, and pathologically with therapeutic eradication of the H. pylori. H. pylori infection may be a treatable cause of at least some cases of HLG and should therefore be carefully sought in any patient with this condition.

Amoxicillin↗
PubMed1994

Correcting the PiZ defect in the alpha 1-antitrypsin gene of human cells by targeted homologous recombination.

BACKGROUND: Approximately 1% of people in North America carry the PiZ defect in the gene encoding the serum protein alpha 1-antitrypsin (AAT). Homozygotes are subject to early onset emphysema and liver disease. Here we demonstrate a means of correcting this gene defect, a point mutation in chromosome 14, by targeted homologous recombination. EXPERIMENTAL DESIGN: To target recombination to the AAT locus in human cells we use a normal complementary DNA cleaved once approximately 400 base pairs upstream of the PiZ mutation site in exon V. After transfection, targeting is monitored using a polymerase chain reaction assay devised to uniquely amplify successful homologous recombinants. RESULTS: When excercised on human PiZZ GM2522 fibroblasts, targeting replaces exon V of the endogenous gene, containing the PiZ mutation, with the exon V counterpart of a normal complementary DNA, simultaneously displacing the mutated exon V away from its promoter. By reversing the targeting strategy and using human PiM hepatoma cells, we have been able to supplant a normal copy of the AAT gene with a mutated PiZ version. This has allowed us to culture human HepG2 cells expressing the pathologic phenotype of the PiZ defect. Immunocytologic staining demonstrates the presence of inclusions in the liver cells due to aggregation of the PiZ isoform encoded by the recombined AAT gene under control of the endogenous gene promoter. CONCLUSIONS: (a) Targeting to the AAT locus is observed, using the methods we have developed, at rates that render feasible the selection of targeted cells and isolation of clones bearing a corrected AAT gene. (b) Correction of the exon V PiZ mutation alone, regardless of an accompanying exon III mutation, is sufficient to prevent aggregation of the PiZ protein in human liver cells. (c) Targeted homologous recombination offers advantages in potential gene therapy to correct AAT defects.

Animals↗
PubMed1994

Adenocarcinoma in strictures of ulcerative colitis without antecedent dysplasia by colonoscopy.

We report three patients with chronic ulcerative colitis and colonic strictures that were found to harbor advanced adenocarcinomas despite previous endoscopic examinations that had failed to demonstrate dysplasia or carcinoma. This experience calls into question the reliability of endoscopic monitoring of the subset of ulcerative colitis patients with strictures. Review of the literature supports the thesis that the management of these patients requires a high index of suspicion of malignancy, and should include timely consideration of surgery. It is suggested that evaluation of the effectiveness of endoscopic surveillance programs for patients with ulcerative colitis should consider the subset of patients with strictures as a separate cohort.

Adenocarcinoma↗
PubMed1993

The leukocyte adherence inhibition test (LAI) in preoperative diagnosis of epithelial ovarian cancer.

One hundred two women admitted for evaluation of an adnexal mass were tested prior to surgery by the computerized tube leukocyte adherence inhibition (LAI) assay. The test was positive in 24/35 (69%) patients, diagnosed after surgery as epithelial ovarian cancer while 50/67 (75%) of those diagnosed as benign masses were negative. Only 2/38 (5%) of normal control subjects showed a false-positive result. The LAI test described in this report showed a sensitivity of 88% and a specificity of 75% in stage I ovarian cancer; thus it may be useful for early diagnosis of ovarian malignancy.

Adnexal Diseases↗