Expression of transforming growth factor beta(1), beta(3), and basic fibroblast growth factor in full-thickness skin wounds of equine limbs and thorax.

OBJECTIVE: To map the expression of transforming growth factor (TGF)-beta(1), TGF-beta(3), and basic fibroblast growth factor (bFGF) in full-thickness skin wounds of the horse. To determine whether their expression differs between limbs and thorax, to understand the pathogenesis of exuberant granulation tissue. STUDY DESIGN: Six wounds were created on one lateral metacarpal area and one midthoracic area of each horse. Sequential wound biopsies allowed comparison of the temporal expression of growth factors between limb and thoracic wounds. ANIMALS: Four 2- to 4-year-old horses. METHODS: Wounds were assessed grossly and histologically at 12 and 24 hours, and 2, 5, 10, and 14 days postoperatively. ELISAs were used to measure the growth factor concentrations of homogenates of wound biopsies taken at the same timepoints. RESULTS: TGF-beta(1) peaked at 24 hours in both locations and returned to baseline in thoracic wounds by 14 days but remained elevated in limb wounds for the duration of the study. Expression kinetics of TGF-beta(3) differed from those of TGF-beta(1). TGF-beta(3) concentrations gradually increased over time, showing a trend toward an earlier and higher peak in thoracic compared with limb wounds. bFGF expression kinetics resembled those of TGF-beta(1), but no statistically significant differences existed between limb and thoracic wounds. CONCLUSIONS: Growth factor expression is up-regulated during normal equine wound repair. TGF-beta(1) and TGF-beta(3) show a reciprocal temporal regulation. Statistically significant differences exist between limb and thoracic wounds with respect to TGF-beta(1) expression. CLINICAL RELEVANCE: The persistence of TGF-beta(1) expression in leg wounds may be related to the development of exuberant granulation tissue in this location, because TGF-beta(1) is profibrotic.

Recurrent pregnancy loss associated with endometrial hyperechoic areas (endometrial calcifications): a case report and review of the literature.

Endometrial calcifications occur sporadically and are associated with infertility. Previous uterine trauma during instrumentation and/or uterine infection are likely involved in their pathogenesis. The association between endometrial calcifications and recurrent pregnancy loss has been very infrequently reported. A 28-year-old woman with a history of two consecutive first trimester pregnancy losses presented with ultrasonographic hyperechoic endometrial areas associated with histologic endometrial calcification foci. A third pregnancy conceived before starting micronized oral progesterone supplementation also spontaneously aborted at eight weeks. During the fourth pregnancy, progesterone supplementation was taken for the initial 12 weeks. The endometrial lesions were no longer detectable and the pregnancy progressed to term without complications. Endometrial calcifications, related to intrauterine bone tissue, have been previously treated with curettage or with endoscopic surgery, and to the best of our knowledge, have not been reported to disappear spontaneously. In this case, regression of the endometrial calcifications and a favorable pregnancy outcome occurred in concert with oral micronized progesterone supplementation. A combination of transvaginal ultrasonography and endometrial biopsy appears to be an effective method for diagnosing and monitoring of this rare condition.

The spectrum of neuroendocrine differentiation among gastrointestinal carcinoids: importance of histologic grading, MIB-1, p53, and bcl-2 immunoreactivity.

CONTEXT: The advent of panneuroendocrine markers has helped to better depict the heterogeneity of gastrointestinal carcinoids. Consequently, it has been proposed that these tumors constitute a histologic spectrum that includes well-, moderately, and poorly differentiated carcinoids. However, the reproducibility of this grading system and its prognostic importance have sometimes been called into question. OBJECTIVE: To investigate the potential utility of cell proliferation and oncoprotein markers in augmenting the histologic classification. DESIGN AND SETTING: Retrospective study; tertiary care teaching hospital. METHODS: Fifty-eight patients with 41 well-differentiated, 12 moderately differentiated and 5 poorly differentiated carcinoids from various topographic sites of the gastrointestinal tract were selected and immunostained for panneuroendocrine markers, MIB-1, p53, and bcl-2. MAIN OUTCOME MEASURES: Degree of association between histologic grading, MIB-1, p53, and bcl-2 immunoreactivity and carcinoid metastatic behavior. RESULTS: The group comprised 30 males and 28 females whose mean age was 52.7 years (range, 14-81). Mean follow-up time was 85.8 months. All 58 patients tested positive for chromogranin A and/or synaptophysin. The group was divided into nonmetastatic (42/58, or 72.4%) and metastatic (16/58, or 27.6%) cases. Histologic grading tended to be associated with metastatic spread, but this occurrence of metastases did not attain statistical significance (P =.08). Positivity for MIB-1 (P =.004) and p53 (P =.04) was significantly associated with metastatic behavior, whereas bcl-2 was not (P = 0. 63). CONCLUSIONS: Although an organoid pattern and neuroendocrine immunophenotype help to define the spectrum of gastrotestinal carcinoids, this study suggests that the histologic grading of these tumors has some limitations with respect to predicting metastatic behavior. However, MIB-1 and p53 can compliment histologic grading as prognostic indicators in this regard while bcl-2 appears to be less useful.

N-myristoyltransferase.

Myristoylation refers to the co-translational addition of a myristoyl group to an amino-terminal glycine residue of a protein by an ubiquitously distributed enzyme myristoyl-CoA:protein N-myristoyltransferase (NMT, EC 2.3.1.97). This review describes the basic enzymology, molecular cloning and regulation of NMT activity in various pathophysiological processes such as colon cancer and diabetes.

The impact of endoscopic technology on gastrointestinal pathology.

Since its introduction in the 1950s, fiberoptic endoscopy has dramatically altered the scope and practice of gastrointestinal (GI) pathology. Whereas examination by rigid instruments was generally restricted to the proximal digestive foregut and distal 25 cm of the large bowel, fiberoptic endoscopy extended these limits considerably, which resulted in a greater volume of biopsies submitted to the pathology laboratory. Furthermore, this technique is associated with a lesser degree of patient discomfort and a lower risk of complications compared to rigid or semiflexible endoscopy. In established endoscopy units, flexible endoscopy is performed increasingly with the videoscope rather than the fiberscope. With the added advantage of direct visualization, flexible endoscopy has eclipsed barium radiology as the premier investigative modality for GI diseases. Although upper GI endoscopy and colonoscopy account for the majority of biopsy material, there are other flexible endoscopic techniques, including endoscopic retrograde cholangiopancreatography and enterostomy. Flexible endoscopy has not only impacted the diagnosis of important disease entities (eg, reflux esophagitis, H. pylori gastritis, celiac disease and GI polyps and neoplasia), but it has also become a key component of surveillance protocols for dysplasia in Barrett's esophagus and idiopathic inflammatory bowel disease. Predicting major trends that may emerge from (GI flexible endoscopy in the future is somewhat difficult, but promising new avenues of investigation include increased use of endoluminal ultrasound and trans-bowel fine needle aspiration. Biopsy material will be submitted with more frequency for genetic molecular studies such as tumor development and progression and identification of infections agents; the priorities for handling biopsy material may have to be re-examined. Gastrointestinal (GI) biopsies constitute a substantial proportion of the surgical pathology load in most tertiary care medical centers. Based on topographic site of origin, the GI tract is the single largest component of the biopsy service in this institution. This relates in part to the high frequency of patients' complaints referable to the digestive tract and is also a result of the advances in GI endoscopy that have led to more widespread application of this technique. To gain a better appreciation of the impact of the changes in endoscopic techniques on gastrointestinal pathology, it is pertinent to examine the historical perspective from which the technology arose.

A case of peripartum eosinophilic myocarditis.

A 19-year-old postpartum patient with a previous history of asthma and eosinophilic myocarditis is described. Eosinophilic myocarditis is thought to be caused by exacerbation of the idiopathic hypereosinophilic syndrome by pregnancy. The diagnosis was made by a right ventricular endomyocardial biopsy, which showed an eosinophilic infiltrate with a few scattered foci of myonecrosis, but no fibrosis, vasculitis or granulomas. The patient's myocardial function continued to decline over a two-year follow-up period, despite normal levels of eosinophils. She developed echocardiographic evidence of diastolic and systolic dysfunction.

N-Myristoyltransferase overexpression in human colorectal adenocarcinomas.

Modification of proteins by myristoylation has been proposed as a chemotherapeutic target against colon cancer because it is important in the function of various signal transduction proteins. Recently we reported that the enzyme that catalyzes this modification, N-myristoyltransferase (NMT), is elevated in colorectal adenocarcinomas [Magnuson, B. A., Raju, R. V. S., Moyana, T. N., and Sharma, R. K. (1995) J. Natl. Cancer. Inst. 87, 1630-1635]. The purpose of the present study was to investigate whether the elevated activity of NMT in colorectal adenocarcinomas is due to an increase in the production of NMT or a change in the structure of the preexisting enzyme. The expression of NMT in normal colonic mucosa and adenocarcinomas from human colorectal surgical specimens was studied by immunoblotting, and its localization was confirmed by immunohistochemistry. The molecular weight of NMT was determined by fast protein liquid chromatography. In both normal mucosa and colorectal adenocarcinomas, NMT with a molecular mass of 48.5 kDa was identified with anti-human NMT and anti-peptide antibody. However, the expression of NMT was found to be higher in the colorectal tumors. This finding was further confirmed by immunohistochemical studies which showed stronger cytoplasmic staining in the tumors. These findings represent the first description of NMT overexpression in colorectal adenocarcinomas. This has implications with regard to (i) the design of chemotherapeutic drugs and (ii) prognosis, for instance, in monitoring colorectal cancer recurrence or metastases.

Sporadic ampullary hamartoma simulating cancer.

Ampullary tumours are uncommon. They may occur with familial polyposis syndromes or neurofibromatosis. It can be difficult to distinguish them from their periampullary counterparts on clinical, radiologic or histologic grounds. Because most ampullary and periampullary tumours are malignant, they tend to be treated by radical surgery. A 67-year-old man was seen with a sporadic ampullary hamartoma that simulated cancer. It was successfully treated by local excision through a transverse duodenotomy.

Recent trends in the epidemiology of esophageal cancer. Comparison of epidermoid- and adenocarcinomas.

This was a retrospective study of 306 consecutive patients with esophageal carcinoma seen at the Saskatoon Cancer Center from 1970 to 1992, making an annual incidence of approximately 2.7 percent per 100,000 population. The two main cancer types were (1) epidermoid carcinoma (199 patients or 69 percent), and (2) adenocarcinoma (81 patients or 28 percent). At the time of diagnosis, all patients had advanced disease with > 60 percent having extra-esophageal spread. Patient management was conventional with radiotherapy, surgery, chemotherapy, or combinations thereof being the mainstay of treatment. After a mean follow-up of 13 months, 82 percent of the patients had died of disease, 11 percent of other causes, and none were cured of disease. An analysis of the time trends showed an increasing incidence of both epidermoid carcinomas and adenocarcinomas, particularly the latter. There was a preponderance of distally located tumors in either group. The reasons for these trends in the pathobiology of esophageal carcinoma are not fully understood at this time.

The effect of a synthetic analogue of prostaglandin E2 on wound healing in rats.

This was a prospective, randomized, double-blind experimental study to assess the effect of a long-acting prostaglandin (PG) analogue on wound healing in rats. Eight-cm long, dorsal midline skin incisions were made on rats (n = 44) and immediately resutured. The treatment group (n = 22) received daily intraperitoneal injections of 16,16-dimethyl prostaglandin E2-methyl ester (di-MPGE2) for 7 days, whereas the controls (n = 22) received normal saline. The rats were sacrificed in groups of 11 at 7 and 14 days, respectively. The wounds were excised and analyzed. Histology showed that there was increased fibrosis (p < 0.03) and a decreased number of macrophages (p < 0.02) in the PG group at 7 days. Tensile strength and hydroxyproline content also increased but did not attain significant levels. The differences between the PG and control groups at 14 days similarly did not attain statistical significance. The results suggest that in wound healing, the administration of di-MPGE2 may be beneficial during the early stages of inflammation, rather than during the later stages of remodelling.

Granulomatous appendicitis in acute myeloblastic leukemia: expanding the clinicopathologic spectrum of invasive candidiasis.

The incidence of systemic candidiasis appears to be on the rise, and unusual or hitherto undocumented clinicopathologic features of invasive candidiasis continue to be described. This report adds further to this spectrum by describing granulomatous appendicitis due to invasive candidiasis. The patient was a 23-year-old woman with acute promyelocytic leukemia. Her other risk factors included the use of aggressive chemotherapy, immunosuppressives, broadspectrum antibiotics, and invasive instrumentation. In view of the acquired immunodeficiency syndrome epidemic, as well as the improved survival of patients with prolonged neutropenia owing to better intensive care units, there is reason to believe that other as yet undocumented clinicopathologic manifestations of invasive candidiasis or other opportunistic infections may come to light.

Increased N-myristoyltransferase activity observed in rat and human colonic tumors.

BACKGROUND: Colorectal cancer is one of the leading causes of cancer death in North America. Since treatment of colonic cancer remains difficult because of the lack of effective chemotherapeutic agents, it is important to continue to search for cellular functions that can be disrupted by chemotherapeutic drugs and inhibit the development or progression of this disease. Modification of proteins by myristoylation has been recognized as important in the function of various viral, oncogenic, and signal-transduction proteins and thus has been proposed as a target for chemotherapeutic drug design. However, the activity of the enzyme that catalyzes this modification, N-myristoyltransferase, has not been investigated in cancer relative to normal tissue. PURPOSE: The purpose of this study was twofold: 1) to investigate the activity of N-myristoyltransferase in azoxymethane-induced rat colonic cancer tissue compared with normal and normal-appearing rat colonic tissue and 2) to determine if similar differences would be observed in a small sample of human colonic tumors. METHODS: N-Myristoyltransferase activity was determined in 45 colonic tissue specimens from Sprague-Dawley rats--10 given injections of the colon carcinogen, azoxymethane, and three untreated. Tissue specimens included 35 colonic tumors of varying pathologic stages, seven specimens of normal-appearing adjacent mucosa, and three specimens of normal colonic mucosa. Colectomy specimens from five patients were assayed for N-myristoyltransferase activity. Subcellular distribution of N-myristoyltransferase activity was determined. Synthetic peptides of known myristoylated proteins--pp60src and cyclic adenosine monophosphate-dependent protein kinase--were used in kinetic analyses of N-myristoyltransferase in colonic cancer and normal-appearing colonic tissue. All P values are two-tailed. RESULTS: N-Myristoyltransferase activity was increased in rat colonic tumors compared with normal-appearing adjacent mucosa and normal mucosa (P = .0002). Elevation of N-myristoyltransferase activity was present in all tumors, including colonic polyps. Increased N-myristoyltransferase activity was also observed in human colonic tumors and was predominantly cytosolic. N-Myristoyltransferase of colonic cancer tissues had a similar Michaelis constant but an approximate twofold higher maximum velocity for both the pp60src- and cyclic adenosine monophosphate-dependent protein kinase-derived peptides compared with N-myristoyltransferase of normal-appearing tissue. CONCLUSIONS: This study demonstrates for the first time that N-myristoyltransferase activity is higher in colonic epithelial neoplasms than in normal-appearing colonic tissue and that an increase in N-myristoyltransferase activity appears at an early stage in colonic carcinogenesis.

Single jejunoileal and right colonic carcinoids as midgut tumors. A study collating immunophenotypes and histogenesis.

The jejunoileum and the right colon, both of which are located in the midgut, have some histologic similarities such as the presence of Paneth cells and intraepithelial endocrine cells (IEECs). Since gastrointestinal (GI) carcinoids arise from the same stem cells as GI endocrine cells, the question was whether or not there might also be similarities in the histogenesis of jejunoileal carcinoids (JICs) and right colonic carcinoids (RCCs). Ten single JICs and 3 RCCs together with their respective controls were stained using various neurohormonal immunoreagents. Our results showed that neither the JICs nor the RCCs appeared to arise from a background of diffuse IEEC hyperplasia. Furthermore, in the jejunoileum, serotonergic progenitor cells appear to have a proclivity for neoplastic transformation, as do cells of the pancreatic polypeptide and glucagon lineage in the right colon.

Expression of tumor-associated polymorphic epithelial mucin and carcinoembryonic antigen in gastrointestinal carcinoid tumors. Implications for immunodiagnosis and immunotherapy.

BACKGROUND: Gastrointestinal neoplastic epithelium of glandular origin commonly produces N-linked and O-linked glycoproteins such as carcinoembryonic antigen (CEA) and tumor-associated polymorphic epithelial mucin (PEM). Antibodies to these glycoproteins increasingly are being used in immunodiagnosis and/or immunotherapy. Although GI carcinoid tumors have a neuroendocrine immunophenotype and generally have an indolent clinical course compared with their adenocarcinomatous counterparts, they also arise from undifferentiated crypt epithelium. The purpose of this study was to determine whether GI carcinoids similarly expressed epitopes for CEA and PEM. METHODS: Thirty-nine GI carcinoid tumors from various topographic sites were analyzed by immunohistochemistry using the murine monoclonal antibodies B72.3, ACT19, and T84. The former two antibodies recognize epitopes in PEM, whereas the latter is an anti-CEA antibody, which was confirmed using enzyme-linked immunosorbent assays. RESULTS: The majority of carcinoid tumors (74%), particularly jejunoileal carcinoids, reacted for ACT19 antibody, whereas considerably fewer reacted for B72.3 (31%) and T84 (26%). The extent of staining was also greatest with ACT19. The GI mucosa adjacent to or overlying the carcinoid tumors also stained for the various antibodies. CONCLUSIONS: The extent and degree of positivity of carcinoid tumors for ACT19 raises the possibility that this antibody may be used in the future for the radioimmunodiagnosis and/or immunotherapy of these tumors, particularly in cases that are multicentric, unresectable, or with metastatic disease.

Development of the early mucosal lesions in experimental inflammatory bowel disease--implications for pathogenesis.

The purpose of this study was to better establish the morphologic basis of the early mucosal lesions of experimental inflammatory bowel disease because understanding the development of these lesions has important pathogenetic implications. Sprague-Dawley rats were given 1.5% hydrolyzed lambda-carrageenan orally for 30 days. This produced small intestinal lesions which were then evaluated. Light microscopy showed an increased amount of inflammatory cells in the gut wall with prominent Peyer's patches, microgranulomas, crypt abscesses, pin-point ulcerations, and a repair reaction. Scanning electron microscopy revealed pin-point ulcerations in relation to Peyer's patches. Transmission electron microscopy, in addition to the above findings, showed disruptions of enterocyte microvilli and terminal webs. Follicle-associated epithelium appeared to be a predictive site for the development of crypt abscesses and pin-point ulcerations. Enzyme-linked immunoadsorbent assays indicated that orally administered carrageenan elicited a systemic antibody response. Our results suggest that damage to enterocyte microvilli and terminal webs may be important early events in the morphogenesis of the lesions.

Crypt cell proliferative micronests in rectal carcinoids. An immunohistochemical study.

Gastrointestinal endocrine cells are situated both in the epithelium as well as in the subepithelium, especially in relation to enteric nerves. This has complicated efforts at delineating the histogenesis of gastrointestinal carcinoids. However, gastrointestinal carcinoids themselves are a heterogeneous group made up of various subsets, and as such may have different modes of origin. The present study investigated the histogenesis of rectal carcinoids because this has not been adequately addressed. Nine rectal carcinoids together with sex- and age-matched controls were stained with silver stains and various immunoreagents. The number of intraepithelial endocrine cells per unit length of mucosa in the carcinoid group was compared with the controls using the Student t test. Our results showed that there was no evidence of diffuse intraepithelial endocrine cell hyperplasia associated with these carcinoids. In six of the cases, however, there were focal areas where the carcinoids abutted onto the mucosal epithelium, and in another two cases there were focal areas depicting crypt cell proliferative micronests. These findings suggest that most conventional rectal carcinoids arise from localized areas of crypt cell proliferation rather than from diffuse areas of intraepithelial endocrine cell hyperplasia. Furthermore, rectal carcinoids appear to be constituted of a heterogenous population of endocrine cells rather than a monoclonal population of cells with each cell expressing a multiplicity of hormones.

Colorectal leiomyosarcomas: a pathobiologic study with long-term follow-up.

Colorectal leiomyosarcoma (CLM) is an uncommon tumour. Reports of its occurrence have been published mostly as single cases or small series. This study documents 12 cases of CLM that were seen over a 28-year period in Saskatchewan. The annual incidence of CLM was 0.45 per million people and constituted 0.12% of all colorectal malignant tumours seen during the study period. CLMs had a predilection for the rectum and sigmoid and commonly were associated with rectal bleeding or abdominal pain. More than half the tumours were detected by sigmoidoscopy. A correct preoperative or intraoperative histologic diagnosis of leiomyosarcoma was made in only two out of six cases. A potentially curative surgical procedure was done in 10 of the 12 patients. The mean follow-up was 6.9 years. Eight patients had tumour recurrence or metastasis, or both. From the findings of this study the authors recommend wide excision of colorectal smooth-muscle tumours whenever there is a suggestion of malignancy.

A comparative immunohistochemical study of jejunoileal and appendiceal carcinoids. Implications for histogenesis and pathogenesis.

BACKGROUND: The purpose of this study was to determine the histogenesis of jejunoileal and appendiceal carcinoids and to ascertain whether this could be useful in further explaining the pathology of these neoplasms. METHODS: Eight cases each of multiple jejunoileal carcinoids and appendiceal carcinoids together with their respective age-matched and sex-matched controls were stained with silver stains, chromogranin A, serotonin, and S-100. Histomorphometric evaluations of the endocrine cells in the mucosa adjacent to the carcinoids were carried out and compared with the respective controls using the Student's t test. RESULTS: All the carcinoids from both groups stained for argyrophilia, argentaffinity, chromogranin A, and serotonin. Histomorphometric evaluations showed intraepithelial endocrine cell hyperplasia (IECH) in the jejunoileal carcinoid group (P = 0.007, chromogranin; P = 0.004, serotonin) but not in the appendiceal carcinoid group. On the other hand, subepithelial endocrine cell aggregates that were separate from the main tumor were seen in two cases of appendiceal carcinoids. With S-100, all appendiceal carcinoids showed intrinsic tumor positivity whereas the jejunoileal carcinoids did not. CONCLUSIONS: The finding of IECH with multiple jejunoileal carcinoids suggests that these carcinoids arise from a field effect. The absence of IECH with appendiceal carcinoids as well as their association with subepithelial endocrine cell aggregates and their intimate relationship with Schwann cell processes suggests that appendiceal carcinoids arise from a more discrete unit, the subepithelial neuroendocrine complex.