Detecting alterations in cell ultrastructure with optical imaging

Understanding cell functioning at the nanoscale has been hampered in part by the diffraction limited resolution of optical microscopy. We developed partial wave spectroscopic (PWS) microscopy that is capable of quantifying statistical properties of cell structure at the nanoscale. Our animal and human studies demonstrated that alterations in the nanoscale cell architecture is one of the earliest events in carcinogenesis and precedes any other known morphological changes at larger length scales (i.e. microarchitecture).

Localised massive tumourous xanthomatosis of the small intestine

INTRODUCTION

There are various disorders of the intestine described with accumulations of vacuolated macrophages including single or multiple xanthelasmata, Wolman's disease, cholesteryl ester storage disease (CESD), xanthomatogranulomatotic disease and xantheloma disseminatum.

CLINICAL CASE

In this paper, we report on an exceptional case of a 68-year-old male patient with a localised, massive accumulation of vacuolated, most likely lipid-loaded macrophages with an infiltrative pattern in the muscularis mucosa and propria of the small intestine leading to a tumourous mass requiring surgical removal due to impaired gut function. No enlargement of the liver or the spleen and no evidence of general abnormal lipid storage were detected elsewhere. No evidence of Wolman's or CESD was present. Also, on the ultra-structural level, the macrophages contained no cholesterol clefts typical for either Wolman's and CESD. Instead, largely empty, partly large vacuoles were seen, which most likely contained fatty acids removed during processing.

DISCUSSION

The pathogenetic mechanism of the massive local accumulation of histiocytic cells in this part of the intestine in our case remains un-clear. In summary, this case demonstrates that on rare occasions histiocytic proliferations can mimic tumourous masses with severe functional impairment of the intestine and thus should be in the differential diagnosis of gastrointestinal motility disorders.

Retroviral inclusions in the enteric smooth muscle of a tumor-bearing young chicken

A 15-cm segment of small intestine from a 7-wk-old broiler chicken presented for slaughter was encased by a firm, white mass. Other tissues were grossly unremarkable. Microscopically, the enteric serosa and peripheral muscularis of this segment of small intestine were replaced by a fibrosarcoma. Numerous linear, intracytoplasmic, eosinophilic inclusion bodies were present in smooth muscle cells of the muscularis of the small intestine, and a few similar inclusions were present in the muscularis of the proventriculus. In the heart, there were rare intracytoplasmic inclusions typical of viral matrix inclusions. Ultrastructurally, inclusion bodies in enteric smooth muscle were viral matrix inclusions, and virions resembling avian retroviruses were present in adjacent intercellular spaces. Polymerase chain reaction (PCR) of the deoxyribonucleic acid (DNA) extracted from tumor tissues indicated the presence of proviral DNA of subgroup J avian leukosis virus. This is the first description of the light microscopic appearance of these viral matrix inclusions in enteric smooth muscle.

Intracellular, intercellular, and stromal invasion of gastric mucosa, preneoplastic lesions, and cancer by Helicobacter pylori

BACKGROUND AND AIMS

It is not clear how Helicobacter pylori, an apparently extracellular pathogen colonizing the luminal side of the gastric epithelium, invariably causes an immune-inflammatory response on the stromal side of the mucosa. Penetration of H pylori into epithelial cell lines and its interaction with immune-inflammatory cells have been documented in vitro. Several investigations also showed in vivo bacterial penetration into the epithelium up to the lamina propria; however, the identification as H pylori of the bacteria-like bodies observed in unchanged, metaplastic, or neoplastic mucosa remained sometimes questionable.

METHODS

To search for bacteria-like organisms, we used transmission electron microscopy on endoscopic biopsy specimens from 20 dyspeptic subjects and surgical specimens of neoplastic and nonneoplastic mucosa from 20 cancerous stomachs. To ascertain the H pylori nature of the organisms found, we used 6 different antibodies directed against bacterial lysates, purified vacuolating cytotoxin A, or purified cytotoxin-associated antigen A in immunogold tests. The results were compared with those of H pylori strains cultivated in vitro.

RESULTS

In nonmetaplastic gastric epithelium, cytochemically proven H pylori were detected, in the majority of cases, inside cytoplasm of epithelial cells, in intraepithelial intercellular spaces, and in underlying lamina propria, often in direct contact with immune-inflammatory cells and sometimes inside small blood vessels. Cytochemically proven H pylori were also observed inside 6 of 8 intestinal metaplasias and 9 of 20 cancers.

CONCLUSIONS

H pylori penetrates normal, metaplastic, and neoplastic gastric epithelium in vivo, intracellularly, or interstitially to cause a strong immune-inflammatory response and promote gastric carcinogenesis.

Intestinal type adenocarcinoma: a previously unrecognized histologic variant of ductal carcinoma of the pancreas

Adenocarcinomas with intestinal differentiation have been described in a wide variety of anatomical sites. To our knowledge, however, ductal adenocarcinomas with intestinal phenotype have not been described in the pancreas. We report here 11 ductal carcinomas of the pancreas that were morphologically similar to colonic adenocarcinomas. These pancreatic carcinomas of intestinal type represented 10% of 110 consecutively removed ductal carcinomas of the pancreas. All intestinal type carcinomas expressed cytokeratin 7, carcinoembryonic antigen, CDX2, and MUC2. The pattern of reactivity of cytokeratin 7 and carcinoembryonic antigen was diffuse, whereas that of mucin 2 staining and CDX2 nuclear labeling was focal and confined predominantly to goblet cells and less frequently to columnar cells. Six carcinomas contained collections of endocrine cells admixed with the columnar and goblet cells. Five carcinomas were associated with high-grade pancreatic intraepithelial neoplasia of intestinal type. Six patients were female and 5 were male. Their ages ranged from 52 to 76 years (mean age, 61 years). The clinical presentation did not differ from that of the conventional ductal carcinomas. All carcinomas originated in the head of the pancreas, and 5 had metastasized to the regional lymph nodes at the time of surgical resection. Only 1 patient survived 5 years. Three patients are disease free from 2.8 to 8.9 months after surgery. Six patients died as a direct result of the carcinomas, and 1 was lost to follow-up. More studies are needed to determine the biologic behavior of this distinctive histologic variant of ductal adenocarcinoma of the pancreas.

Intestinal perineuriomas: clinicopathologic definition of a new anatomic subset in a series of 10 cases

Benign peripheral nerve sheath tumors are uncommon in the gastrointestinal tract, and perineuriomas have not previously been reported to occur at this anatomic location. In this study, we analyzed the clinicopathologic and immunohistochemical features of 10 perineuriomas arising in the intestine. Eight patients were female and 2 male (median age, 51 years; range, 35-72 years). Eight of the lesions were intramucosal perineuriomas presenting as small sessile polyps detected during colonoscopy; 6 of these 8 patients were asymptomatic and undergoing colorectal cancer screening. The remaining 2 cases were submucosal masses, one each located in the colon and jejunum. Of the mucosal polyps, six were located in the rectosigmoid or sigmoid colon and one each was detected in the descending colon and transverse colon. The polyps ranged from 0.2 to 0.6 cm (median, 0.4 cm) in greatest dimension. The colonic and jejunal masses measured 3 cm and 4.5 cm, respectively. Histologically, the intramucosal perineuriomas were composed of uniform bland spindle cells having ovoid to elongated nuclei and pale indistinct cytoplasm, with no cytologic atypia, pleomorphism, or mitotic activity. The lesions had a fine collagenous stroma, demonstrated irregular borders with the adjacent lamina propria, and entrapped colonic crypts. Five cases exhibited hyperplastic changes in the adjacent or entrapped epithelium. The colonic submucosal tumor was microscopically well circumscribed, whereas the jejunal perineurioma showed focal infiltration through the muscularis propria into the subserosa. The stroma was collagenous in the colonic tumor and predominantly myxoid in the jejunal tumor. The spindle cells in the submucosal perineuriomas demonstrated tapered nuclei and elongated bipolar cytoplasmic processes. All tumors except one were positive for epithelial membrane antigen (EMA); 4 of 10 expressed claudin-1 and 2 of 10 expressed CD34. All tumors were negative for S-100 protein, glial fibrillary acidic protein, neurofilament protein, smooth muscle actin, desmin, caldesmon, KIT, and pan-keratin. Electron microscopy was performed on the tumor lacking EMA expression, revealing typical features of perineurioma, namely, spindle cells with long bipolar cytoplasmic processes and prominent pinocytotic vesicles, surrounded by discontinuous basal lamina. Clinical follow-up was available for 4 patients (median, 34 months; range, 8-53 months). No tumor recurred. In summary, perineuriomas may arise in the intestine, most often as intramucosal lesions detected as colorectal polyps with distinctive histologic features including entrapment of colonic crypts. Distinguishing perineuriomas from other spindle cell neoplasms of the gastrointestinal tract can be facilitated by immunostaining for EMA and claudin-1.

[Sample preparation for electron microscope with tissues fixed with formalin and embedded in paraffin]

A method of sample preparation for electron microscope is introduced. After paraffin-embedded tissues, fresh and fixed on time, were deparaffined, the tissue were fixed in 4% glutaraldehyde for 24 hours, in 1% osmic acid for 1-2 hours, and dehydrated with acetone and embedded in Epon812; then they were cut into ultrathin sections. By this method, better ultrastructure of paraffin-embedded tissues was obtained, and the method could satisfy the demand for observation under electron microscope. In addition, some important proceedings were also discussed in the paper.

[Deposition of keinoid fibers in gastrointestinal stromal tumors of the small intestine. Report of two cases and review of the literature]

Skeinoid fibers are interstitial collections of a pathological collagen, most often seen in gastrointestinal stromal tumors. They were first described in 1991. We report two cases of intestinal stromal tumors, one in an exceptionally young patient with excessive skeinoid fiber deposition. The microscopic as well as the ultrastructural findings of skeinoid fibers are demonstrated and their role is discussed considering the newest literature.

Integrin alphavbeta3 promotes anchorage-dependent apoptosis in human intestinal carcinoma cells

A population of cells surviving during prolonged incubation in suspension (anoikis-negative cells) were selected from the original anoikis-positive human intestinal carcinoma cell line Caco-2. Anoikis-negative cells are characterized by a strong transcriptional downregulation of the alphav-integrin chain as detected by FACS analysis, RT-PCR and Northern blotting. This finding suggested that alphav-integrin generates a signal stimulating apoptosis of Caco-2 cells upon their detachment from the extracellular matrix. Two lines of evidence supporting this suggestion were provided. First, activation of the alphavbeta3 integrin on Caco-2 cells by their treatment with an alphavbeta3-specific monoclonal antibody resulted in marked stimulation of anoikis. Second, treatment of Caco-2 cells with alphav-specific antisense oligonucleotide resulted in downregulation of the expression of alphav chain and in elevated resistance of these cells to anoikis. Thus, for the first time, our data prove that alphavbeta3 integrin can be an active transducer of apoptosis-stimulating signals generated in response to disruption of the cell-matrix contacts.

IgG-mediated histamine release from canine mastocytoma-derived cells

BACKGROUND

Recent data suggest that normal tissue mast cells can express functional receptors for IgG under certain conditions. However, little is known about IgG receptor expression and functional consequences in mast cell neoplasms.

METHODS

In this study, neoplastic mast cells were obtained from a dog with cutaneous mastocytoma (CM-MC) and from a dog with visceral mastocytoma (VI-MC). Both cell populations were characterized morphologically and functionally.

RESULTS

Most cells proliferated constantly in suspension without particular supplements. Doubling times of CM-MC and VI-MC were 52.2 and 27.5 h, respectively. Both cell types were sensitive to formalin fixation, did not contain heparin and were tryptase and chymase positive. Electron microscopy showed fine granules with electron-dense content in both cell populations. The total histamine content of CM-MC and VI-MC was 0.25 and 0.10 pg/cell, respectively. Calcium ionophore A23187 and substance P induced dose-dependent histamine release, whereas compound 48/80 had no effect. Most significantly, both cell types, when sensitized with monomeric dog IgG, released histamine upon stimulation by anti-dog IgG.

CONCLUSIONS

Dog mastocytoma-derived cells may be useful to study the regulation of neoplastic mast cell growth and differentiation, as well as IgG receptor-mediated activation in neoplastic mast cells. Further research is required to clarify the pathophysiological significance of constitutive expression of IgG receptors in neoplastic (canine) mast cells.

Comparative ultrastructural study of cytotoxic granules in nasal natural killer cell lymphoma, intestinal T-cell lymphoma, and anaplastic large cell lymphoma

Comparative immunohistochemical and ultrastructural studies were performed on five nasal natural killer (NK) cell lymphoma cases, two intestinal T-cell lymphoma cases, and eight anaplastic large cell lymphoma (ALCL) cases to clarify morphological differences in cytotoxic granules among these cytotoxic lymphomas. Nasal NK-cell lymphomas and intestinal T-cell lymphomas had fine azurophilic granules and displayed dot-like immunostaining of granzyme B- and T-cell intracellular antigen 1 (TIA-1), predominantly in the central area of the cytoplasm. Ultrastructurally, these NK-cell lymphomas and intestinal T-cell lymphomas had two types of cytotoxic granules, type-I granules (dense core granules) and type-II granules (multivesicular bodies), which have been demonstrated in normal large granular lymphocytes in peripheral blood. However, ALCLs did not have azurophilic granules, and only type-II cytotoxic granules were found ultrastructurally, even though they showed similar dot-like immunostained patterns of granzyme B and TIA-1, as seen in NK-cell lymphomas and intestinal T-cell lymphomas. Immunoelectron microscopy revealed that TIA-1 was primarily located at the periphery of the cytoplasmic granules in the NK-cell lymphoma and ALCL cases. These findings suggest that malignant lymphomas with a cytotoxic phenotype can be divided into two types, (azurophilic granule)+, (type-I granule)+, (type-II granule)+ lymphomas and (azurophilic granule)-, (type-I granule)-, (type-II granule)+ lymphomas.

Duodenal periampullary gangliocytic paraganglioma: report of two cases with immunohistochemical and ultrastructural study

We report two cases of Gangliocytic Paraganglioma (GP) of the ampulla of Vater occurring in a 63-year-old and a 34-year-old individual. The patients were both admitted for a long history of intermittent gastrointestinal bleeding and abdominal discomfort, with no other symptoms. At endoscopy, the GP appeared as a polypoid, ulcerated mass in the ampullar region, measuring 2.5x1.8 and 2 cm, respectively. Microscopically, the tumors showed similar features and were composed of epithelial cells (more than 50%), spindle cells, and ganglion-like cells. The epithelial cells showed clear cytoplasm and formed nests (zellballen or paraganglioma-like groups), and less frequently, cords (carcinoid-like), extending to mucosa and submucosa. Ganglion cells were sparse, constantly associated with the spindle cells. Both epithelial and ganglion cells were synaptophysin, chromogranin A, and anti-neurofilament immunoreactive. The spindle cells were all S-100 positive. Ultrastructural studies revealed dark and light cells, rare elongated cellular processes, secretory granules, and fine fibrils resembling neurofilaments. The histogenesis of GP is still a matter of debate, however its neoplastic nature is supported by the occasionally reported malignant evolution.

Nuclear localization of 111In after intravenous injection of [111In-DTPA-D-Phe1]-octreotide in patients with neuroendocrine tumors

Treatment with tumor-targeting substances is currently being evaluated in clinical trials. For patients with neuroendocrine tumors expressing somatostatin receptors, the 111In-labeled somatostatin analog [diethylenetriaminepentaacetic acid (DTPA)-DPhe1]-octreotide has been used with promising results. To further investigate the clinical effect of the injected conjugate, we analyzed the cellular distribution of 111In by ultrastructural autoradiography.

METHODS

Seven patients with somatostatin receptor-expressing midgut carcinoid tumors scheduled for abdominal surgery were investigated by somatostatin receptor scintigraphy. During operation, tumor tissue samples and samples of normal intestine were collected, fixed, and processed for electron microscopy. A thin layer of film emulsion was applied on sections and after the exposure film was developed. The cellular distribution of silver precipitations indicating the presence of isotope was evaluated.

RESULTS

Cell surface receptor binding and internalization of [111In-DTPA-D-Phe1]-octreotide in the tumor cells was easily revealed by silver precipitations in the film. Multiple silver grains were seen at the plasma membrane, in the cytoplasmic area among secretory granules and vesicular compartments, and in the perinuclear area. Silver grains were also regularly located in the nucleus. For all patients, the silver precipitation patterns from 111In decay were identical in all examined cells from removed tumors, and in most cells 111In could be seen in the nucleus. The specificity of the silver reaction products is supported by the observation that enterocytes in intestinal tissue specimens from near the tumor did not show any silver grains and no background labeling was seen in the plastic.

CONCLUSION

After internalization through the somatostatin receptor system, 111In is translocated to the perinuclear area and into the nucleus. Whether the nuclide is still conjugated to the intact somatostatin analog or to part of it cannot be evaluated in this study. Despite the short irradiation range of 111In, the nuclear localization can explain its clinical effectiveness. The results from this study suggest that [111In-DTPA-D-Phe1]-octreotide may act as a powerful tumor cell-targeting substance.

Gastrointestinal autonomic nerve tumor (plexosarcoma): report of a case with fine needle aspiration biopsy and histologic, immunocytochemical and ultrastructural study

BACKGROUND

Gastrointestinal stromal tumors (GISTs) encompass a large group of mesenchymal neoplasms that display common cytologic spindle-shaped morphology on light microscopy. Immunocytochemical and ultrastructural studies can demonstrate several patterns of differentiation.

CASE

A 70-year-old male presented with two intraabdominal small bowel masses. The cytopathologic features of a fine needle aspiration biopsy (FNAB) included plump spindle cells in densely populated aggregates or in a fasciculated pattern, without significant pleomorphism. An epithelioid component in a lobular arrangement with abundant, eosinophilic cytoplasm was also noted. The nuclei were vesicular, with a very evident, eosinophilic nucleolus and finely distributed chromatin. Groups of loosely cohesive cells with slender, dendritic-like cytoplasm were evident. Immunocytochemical study of the embedded, fine needle aspirated fragments of the neoplasm demonstrated immunoreactivity for vimentin and neuron-specific enolase. Cytokeratin immunoreactivity or muscular, vascular, neuroendocrine or nerve sheath differentiation failed to be demonstrated. The cytologic and immunocytochemical findings correlated well with the histologic features of the neoplasm. The morphologic diagnosis was confirmed by ultrastructural study.

CONCLUSION

FNAB and immunocytochemistry can be valuable in making the correct diagnosis between gastrointestinal stromal tumors.

Multiple small intestinal stromal tumors with skeinoid fibers in association with neurofibromatosis 1 (von Recklinghausen's disease)

A case of multiple small intestinal stromal tumors (SIST) with skeinoid fibers of the jejunum arising in a 50 year old male with neurofibromatosis 1 (NF-1) is reported. Seven small tumors of the jejunal wall were incidentally found and excised during an operation for abdominal and retroperitoneal neurofibromas. Histologically, the tumors were composed of uniform spindle-shaped cells with fascicular pattern, almost indistinguishable from the histology in leiomyoma. Periodic acid Schiff stain-positive hyaline globules were observed among the tumor cells. Ultrastructurally, these globules were stromal tangles of curvilinear, fluffy fibrils, consistent with skeinoid fibers. The electron-dense granules, possibly neuro-secretory granules, were found in the cytoplasm of the tumor cells. Immunohistochemically, the tumor cells were positive for vimentin, neuron specific enolase and CD34, but negative for muscle markers and S100 protein. The association of NF-1 and multiple SIST with skeinoid fibers may have clinical implications. The multiple occurrence of SIST with skeinoid fibers seems to be often cited as one of the gastrointestinal manifestations of NF-1. The possible site of origin of SIST with skeinoid fibers in NF-1 may be the enteric autonomic nerve plexus in the small intestinal wall.

Endometrial stromal sarcoma with focal smooth muscle differentiation: recurrence after 17 years: a follow-up report with discussion of the nomenclature

In 1977, a case report was published describing a 28-year-old women with an endometrial stromal tumor that showed foci of myogenic differentiation. The term "stromomyoma" was introduced to encompass both this type of neoplasm as well as "uterine neoplasms resembling ovarian sex-cord tumors" (UTROSCTs). More than 17 years later, the tumor recurred, involving the right ovary, sigmoid colon, small bowel, abdominal wall and omentum. The histologic and electron microscopic similarities between the recurrent tumor and the primary neoplasm were confirmed. Applying the recent classification and diagnostic criteria of endometrial mesenchymal neoplasms, we have concluded that this tumor was a low-grade endometrial stromal sarcoma (LGSS). The formerly proposed term "stromomyoma" implies a benign tumor, in contrast to the obviously malignant nature of this particular tumor. Focal myogenic differentiation of LGSS is not an uncommon finding and does not warrant a separate diagnostic or prognostic entity. UTROSCTs and endometrial stromal sarcomas are two separate diagnostic entities, and combining them under an inclusive terminology is not appropriate.

Differential expression of VIP/PACAP receptor genes in breast, intestinal, and pancreatic cell lines

Vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating peptide (PACAP) are structurally-related neuropeptides that function as trophic factors in addition to their more classical roles as neurotransmitters. Binding and molecular cloning studies have shown that their actions are mediated by receptors encoded by at least three different genes. VIP binding has been demonstrated on many tumor types, and radiolabeled VIP has recently been used as a novel method to localize intestinal tumors in humans and their sites of metastasis. To determine the receptor subtype and level of gene expression, we screened breast, intestinal, and pancreatic, cell lines by Northern blot analysis. Breast lines expressed VIP/PACAP1 receptor mRNA levels comparable to intestinal lines, in agreement with the studies showing particularly high VIP binding in these tumors and their derived cell lines. Pancreatic cell lines expressed mRNA for several receptor types. This extends the potential utility of VIP and PACAP in the localization of tumors, and because VIP and PACAP may regulate the growth rate of some tumors by autocrine or other mechanisms, the identification of receptor subtypes on these lines sets the stage for studies in which the activity of these individual receptors in growth and other processes can be investigated.

Well-differentiated endocrine tumours of the middle ear and of the hindgut have immunocytochemical and ultrastructural features in common

The immunocytochemical analysis of two cases of well-differentiated endocrine tumours (carcinoids) of the middle ear revealed predominant cell populations producing pancreatic polypeptide (PP)-related peptides, glucagon-related peptides, and serotonin (the latter only in one case). In consecutive sections PP- and glucagon-related immunoreactivities mainly colocalized in the same tumour cells. Ultrastructurally tumour cells were characterized by medium-sized to large granules of moderate to high density, on which PP and glicentin were localized by the immunogold technique. No amphicrine cells were found. These features are consistent with those of similar tumours in the rectal mucosa that are mainly composed of L cells coexpressing both PP-related and glucagon-related peptides. Additional tumour antigens of hindgut type detected immunohistochemically were prostatic acid phosphatase and CAR-5 mucin. Expression of the CAR-5 antigen was also found in samples of normal middle ear mucosa, in which endocrine cells have not been identified. In case 1 peritumoral mucosal invaginations showed a proliferation of endocrine cells identical immunophenotypically to tumour cells, possibly representing a precursor lesion. It is concluded that well-differentiated endocrine tumours of the middle ear are a distinct pathological entity characterized by multiple hormone production, typically involving three classes of hormones (pancreatic polypeptide-related peptides, glucagon-related peptides, and serotonin) of the hindgut endocrine system.

Activation of proglucagon gene transcription by protein kinase-A in a novel mouse enteroendocrine cell line

The gene encoding proglucagon is expressed predominantly in the pancreas and intestine. The physiological importance of glucagon secreted from the islets of Langerhans has engendered considerable interest in the molecular control of proglucagon gene transcription in the endocrine pancreas. In contrast, little is known about the molecular control of proglucagon gene expression in the intestine. The recent demonstration that glucagon-like peptide-1 (GLP-1) secreted from the intestine is a potent regulator of insulin secretion and glucose homeostasis has stimulated renewed interest in the factors that control GLP-1 synthesis in the intestinal L-cell. To develop a model for the analysis of intestinal proglucagon gene expression, we have targeted expression of a proglucagon gene-simian virus-40 large T-antigen fusion gene to enteroendocrine cells in transgenic mice. These mice develop intestinal tumors that were used to derive a novel cell line, designated GLUTag, that expresses the proglucagon gene and secretes immunoreactive GLP-1 in vitro. GLUTag cells demonstrate morphological characteristics of enteroendocrine cells by electron microscopy and are plurihormonal, as shown by immunocytochemistry and RNA analyses. GLUTag cells express the proglucagon and cholecystokinin genes, consistent with the pattern of lineage-specific enteroendocrine differentiation described for mouse intestine. Proglucagon gene expression was induced by activators of the protein kinase-A pathway, and a combination of messenger RNA half-life and nuclear run-on experiments demonstrated that the protein kinase-A-induction is mediated by an increase in proglucagon gene transcription. In contrast, activators of protein kinase-C stimulated secretion, but not biosynthesis of the PGDPs in GLUTag cell cultures. Analysis of proglucagon processing in GLUTag cells demonstrated the liberation of glucagon, oxyntomodulin, glicentin, and multiple forms of GLP-1. These observations provide evidence for the direct induction of proglucagon gene transcription by a cAMP-dependent pathway and suggest that the GLUTag cell line represents a useful model for the analysis of the molecular determinants of enteroendocrine gene expression.

[Ultrastructural study of explants of carcinoma of the large intestine during prolonged organ cultivation]

The electron microscopical study on organ cultures of colonic carcinoma has shown that tumour cells form typical for this kind of tumours glandular-like structures which consist of ultrastructural differentiated cells with organospecific features of brush-border and goblet cell types. Depending on the terms of cultivation the consecutive stages of ultrastructural differentiation have been retraced starting from undifferentiated cells (the 5th day of the experiment) up to structurally matured differentiated cells (the 7th-9th days of experiment). The tumour growth in the organ cultures is realized mainly by an explant itself building up processes from its peripheral cell lining and its invagination inside a piece. Glandular-like structures which are forming on the ends of processes and invaginations have undergone further separation. The question of monoclonal origin of colonic carcinoma in organ cultures is discussed.

Small intestinal stromal tumors with skeinoid fibers in neurofibromatosis: report of four cases with ultrastructural study of skeinoid fibers from paraffin blocks

Small intestinal stromal tumors (SIST) with skeinoid fibers (SF) are reported in four patients with neurofibromatosis. SF appeared as intercellular eosinophilic globules that stained positively on periodic acid-Schiff stain and bluish on Masson trichrome stain, like those reported previously. Electron microscopic confirmation of SF was carried out on tissue retrieved from paraffin blocks, which revealed diagnostic ultrastructural features of SF. The association of SIST with SF and neurofibromatosis enhances the diagnostic value of SF as a marker of neurogenic spindle cell tumors. This study also underscores the importance of electron microscopy for differentiation of SF from pseudoskeinoid structures, which may mimic SF on light microscopic examination.

[Surface microscopic patterns of an experimental model of surgically induced carcinogenesis]

An experimental model of carcinogenesis is developed by authors, using internal urinary diversion in Wistar rats. Results show the transformation of normal digestive pattern, discovering proliferative-inflammatory changes at the first time which after go to an histiotypical tumorous pattern. They conclude at the carcinogenicity of the presented surgical model and is described the evolution of the superficial morphological pattern during the tumorigenic process.

Dedifferentiated leiomyosarcoma of the intestinal tract: histological, ultrastructural and immunohistochemical examinations

Six cases of dedifferentiated leiomyosarcoma of the small and large bowel are presented with histological, ultrastructural and immunohistochemical examination. One case arose in the jejunum, two in the ileum, and the other three in the large intestine. The tumours were submucosal in four cases with large areas of ulceration; two were polypoid. Four tumours showed typical leiomyosarcomatous appearance with dedifferentiated components and two were typical leiomyosarcomas at the primary site with differentiated components only in metastatic foci. By immunohistochemistry, typical leiomyosarcomatous areas showed a positive reaction for muscle-specific actin (MSA), MB1, MB2 and myosin. In contrast, desmin-positive cells were scattered throughout the tumour or were not present. Tumour cells in dedifferentiated components were positive for alpha-1-antitrypsin and alpha-1-antichymotrypsin in all cases but one; neuron specific enolase, MB1, MB2 and myosin were positive with variety. MSA was faintly positive in only a few tumour cells of two cases and desmin was not detected in any of the cases studied. Ultrastructurally, tumour cells in typical leiomyosarcomatous areas demonstrated evident smooth muscle features, although in dedifferentiated areas they lacked such features except in one case. Our results indicate that dedifferentiated elements may derive from ordinary leiomyosarcoma and loose muscle features due to dedifferentiation.

[An immunohistochemical and ultrastructural survey on smooth muscle tumors of the alimentary tract]

33 cases of smooth muscle tumors of the alimentary tract were analysed. Among them, 18 cases showed positive reaction to desmin, including one out of two cases of esophageal neoplasms, 6 out of 11 cases of gastric neoplasms, 5 from 12 cases of small intestinal neoplasms, 6 from 8 cases of large intestinal neoplasms, 14 out of 21 cases of benign tumors as well as sarcomas in grade I, and 4 from 12 cases of sarcomas in grade II and III (only mild positive result obtained in grade II and III-sarcomas). S-100 protein staining was performed in 27 cases and positive reaction was obtained only in five. Among them, 2 cases showed prominent positive reaction. 20 cases were studied by electron microscopy, and cytoplasmic myofilaments as well as dense bodies were demonstrated in 7 cases. All of them were the benign neoplasm or sarcoma in grade I. The conclusion is that most stromal tumors of the digestive system are originating from the smooth muscle, except very few cases are neurogenic in origin.

Human gut mucosal mast cells: ultrastructural observations and anatomic variation in mast cell-nerve associations in vivo

One hundred and seventeen coded intestinal biopsy specimens were examined by electron microscopy. All surgical biopsies were obtained from uninvolved sites of patients with two inflammatory bowel diseases (ulcerative colitis or Crohn's disease) and from patients with preneoplastic and neoplastic diseases (adenocarcinoma, rectal polyp, familial polyposis). Biopsy sites included normal ileum, colon, and rectum as well as conventional ileostomies and continent pouches constructed from the ileum. The data reported here describe the ultrastructural anatomy of human gastrointestinal tract mucosal mast cells in vivo and their anatomic associations with enteric nerves.

Skeinoid fibers: an ultrastructural marker of neurogenic spindle cell tumors

The article describes novel stromal fibrillar aggregates found in three cases of neurogenic spindle cell tumor and eight cases of small intestinal stromal tumor. The aggregates were composed of tangles of curvilinear fluffy fibrils with a periodicity of from 41 to 48 nm with a staining pattern similar to that of collagen fibrils. The overall ultrastructural appearance simulated skeins of yarn, hence they are designated skeinoid fibers. No similar stromal fibers were found in more than 5000 other tumors studied. Their exclusive presence in neurogenic spindle cell tumors suggests the possibility that they are an ultrastructural marker for neurogenic spindle cell tumors and that the eight cases of small intestinal stromal tumors with skeinoid fibers may be of neurogenic origin.

Filamentous inclusions of unusual composition and architecture in a metastatic tumor showing myoepithelial differentiation

A hyaline/eosinophilic cytoplasmic inclusion is described in a metastatic tumor occurring in the omentum and bowel of a 32-year-old white woman. The tumor was essentially of round cell type; was positive for cytokeratin, actin, and S-100 protein by immunohistochemistry; and showed desmosomes (maculae adherentes), tonofibrils, modestly developed myofilaments with focal densities, and a basal lamina by electron microscopy. It was therefore interpreted as showing myoepithelial differentiation. Nearly all cells possessed a large, rounded cytoplasmic inclusion that was architecturally unusual, consisting of intermediate filaments intermingled with lattices of fine filaments. The inclusions exhibited an additionally unusual immunohistochemical staining for both cytokeratin and actin. A comparison with cases described in the literature is made.

Pancreastatin-like immunoreactivity in human carcinoid disease

Pancreastatin-like immunoreactivity has been demonstrated in human carcinoid tumors by immunohistochemistry and radioimmunoassay, employing antisera raised to a synthetic C-terminal fragment of porcine pancreastatin. Immunohistochemistry revealed intense immunoreactivity in all tumors. By radioimmunoassay, high concentrations of pancreastatin-like immunoreactivity were measured in carcinoid tumors arising from the fore-gut (mean +/- S.D. and range: 369 +/- 955 and 9.4-3670 pmol g-1, respectively, n = 14), mid-gut (mean +/- S.D. and range: 1354 +/- 1538 and 337-3978 pmol g-1, respectively, n = 5) and in metastases associated with mid-gut tumors (mean +/- S.D. and range: 684 +/- 739 and 31-2255 pmol g-1, respectively, n = 7), compared to corresponding normal tissues (less than 1.4 pmol g-1). Individuals with hepatic metastases and carcinoid syndrome had elevated circulating levels of pancreastatin-like immunoreactivity (mean +/- S.D. and range: 770 +/- 1249 and 42-4120 pmol l-1; n = 12), significantly above the normal, fasting range (mean +/- S.D. and range: 14.9 +/- 7.5 and 4-37.5 pmol l-1, respectively, n = 42). However, patients with non-metastatic carcinoid tumors (n = 4), who had been clinically cured after primary tumor resection, had plasma levels within the normal range. Chromatographic analysis of extracts of primary lung and ileal tumors, hepatic metastases from ileal tumors and plasma from individuals with carcinoid syndrome revealed molecular heterogeneity of pancreastatin-like immunoreactivity.

Intestinal ganglioneuromatosis: mucosal and transmural types. A clinicopathologic and immunohistochemical study of six cases

Six cases of intestinal ganglioneuromatosis (GN) included in this study reveal the occurrence of two morphologic patterns. Transmural GN was characterized by neural hyperplasia in all layers of the bowel wall with predominant involvement of the myenteric plexus. It was found in three patients affected by multiple endocrine neoplasia IIb. Mucosal GN, having predominant involvement of the mucosa without concomitant hyperplasia of the myenteric plexus, was associated with von Recklinghausen's disease, adenocarcinoma of the colon, and multiple adenomas with megacolon in one case each. Clinicopathologic correlations and review of the literature suggest that mucosal GN might represent a distinct entity with a lower morbidity rate than the transmural variant. Immunohistochemical stains reveal considerable heterogeneity. S-100 protein, neuron-specific enolase, and synapto-physin immunostaining followed the distribution of the nervous hyperplasia in the different intestinal layers as identified morphologically and allowed precise determination of the proliferating cells. Increased reactivity for vasoactive intestinal polypeptide, opioid peptides leu-enkephalin and met-enkephalin, and substance P was present in all cases with transmural involvement; mucosal GN showed normal reactivity for opioid peptides and focal increased staining for substance P (one case) and vasoactive intestinal polypeptide (two cases) in the lamina propria. Mild increased immunoreactivity for tyrosine hydroxylase was present in the myenteric plexus of four out of four cases. Histochemical determination of acetylcholinesterase, performed in one case of transmural type, demonstrated hyperplasia of parasympathetic fibers and neurons. Electron microscopic study of another case suggested the presence of several neurotransmitters. These results indicate that the physiopathology of GN is related to a complex hyperplasia of several peptidergic, cholinergic, and probably adrenergic nerve fibers instead of a selective overgrowth of one type of nerve fiber.

Pleomorphic carcinoma of the small bowel. The limitations of immunohistochemical specificity

We report 3 cases of poorly differentiated tumors of the small bowel with histological, immunohistochemical, and ultrastructural studies. The patients were male, aged 45, 57, and 63. In all 3 cases, histological features of spindle cell, epithelioid cell and giant cell areas favoured a diagnosis of carcinoma, although a malignant stromal tumor could not be firmly excluded. Immunohistochemistry demonstrated in the 3 cases a strong expression of both "epithelial" (cytokeratin) and "stromal" (vimentin) markers; one tumor expressed the epithelial membrane antigen, and another one desmin. Electron microscopy showed no specific features in one case. The case positive for desmin demonstrated intracytoplasmic lumina, allowing the diagnosis of carcinoma. In spite of a non-specific immunohistochemical pattern, we finally considered these 3 tumors as of epithelial origin, corresponding to the rare and recently described pleomorphic carcinoma of the small bowel. This report emphasizes the difficult diagnosis of some poorly differentiated tumors, particularly in the gastro-intestinal tract. Such problems had until recently been resolved by ultrastructural and mostly by immunohistochemical studies. However, an increasing number of reports, together with our 3 cases, show unexpected reactivity of tumors with theoretically specific immunoreactions, such as those directed against intermediate filaments. Coexpression of intermediate filaments could be due to cross reactivity of molecules bearing common epitopes, or to the presence of different filaments in the same cell type; recent immunoblotting studies favour this latter hypothesis.

Neoplastic Paneth cells in the experimental murine carcinoma of the small intestine

The purpose of this study is to elucidate the participation of Paneth cells in experimentally induced adenocarcinoma of the intestine. The rats were fed with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) dissolved in drinking water ad libitum at a concentration of 100 micrograms/ml for 28 weeks. They were sacrificed 12 weeks after the last MNNG administration. A number of tumor cells containing large eosinophilic granules in their supranuclear cytoplasm (Paneth cells) were observed in about 20% of the experimentally induced adenocarcinoma of the small intestine. The granules were stained positively with Lendrum, periodic acid-Schiff, Masson's trichrome, and Mallory's phosphotungstic acid hematoxylin. Ultrastructurally, the granules were round, osmiophilic, and relatively even in size. We compared the morphologic features of the Paneth cell-containing small intestinal adenocarcinomas (Group I) with those without Paneth cells (Group II). Group I was distinguished from Group II by its better differentiation, larger tumor size and lower incidence of calcification. Although Paneth cells are extremely rare in human gastrointestinal carcinomas, twenty percent of MNNG-induced intestinal carcinomas harbor Paneth cells. The neoplastic Paneth cells in experimental carcinomas may differentiate from uncommitted cells in the deeper portion of the crypt.

Intestinal schwannoma in a rhesus monkey

An intestinal schwannoma (neurilemmoma) was found in an aged female rhesus monkey culled from a research colony. The neoplasm was characterized principally by palisades of spindle-shaped cells (Antoni type A) surrounded by thick argyrophilic fibres, while plump cells with areas of vacuolation (Antoni type B) were observed to a lesser extent. Thick hyalinized perivascular cuffs were prominent and multifocal thromboses were present in cavernous vascular channels. Electron microscopic examination of the intercellular matrix between Antoni type A cells revealed long-spacing (100 to 120 nm) collagen fibrils. Although the mass had expanded beyond the confines of the muscularis externa, the cytological features of the neoplasm appeared benign.

Development of neuroendocrine tumors in the gastrointestinal tract of transgenic mice. Heterogeneity of hormone expression

Expression of hormones in endocrine tumors and derived cell lines of transgenic mice carrying insulin-promoted oncogenes has been investigated by histochemical, immunohistochemical, ultrastructural, and radioimmunologic means. Tumors of the pancreas, small intestine, mesentery, and liver were examined. Insulin-immunoreactive cells were prevalent in pancreatic tumors, with a significant subpopulation of pancreatic polypeptide-immunoreactive elements. Conventional ultrastructural and immunogold analysis identified insulin-storing beta granules in pancreatic tumor cells. In contrast, the largest immunoreactive subpopulation of intestinal tumors expressed secretin (53% of total cells), followed by proglucagon-related peptides (15%), glucose-dependent insulinotropic polypeptide (7%), gastrin (7%), pancreatic polypeptide (2%), neurotensin (2%), and somatostatin (1%). No detectable immunoreactivity for either insulin or serotonin was observed. Electron microscopy and immunogold labeling showed that intestinal tumor cells contained secretin-storing S-type granules. Lymph node and liver tumors contained secretin-immunoreactive cells with ultrastructural features similar to those of intestinal tumors. In addition, high levels of circulating insulinlike and secretinlike immunoreactants were detectable. Analogous hormone profiles were identified in tumor cell lines and culture media. Large T-antigen immunoreactivity was detected in all the nuclei of neoplastic cells, as well as in insulin-immunoreactive elements of non-neoplastic islets and pancreatic ducts and in some secretin-immunoreactive cells of small intestinal mucosa. These data indicate that neuroendocrine tumors arise both in beta cell and S-cell subpopulations of transgenic mice.

Coexistence of delta sleep-inducing peptide and serotonin in midgut carcinoid tumour cells in vivo and in vitro

By immunocytochemistry, delta sleep-inducing peptide (DSIP) was demonstrated to coexist with serotonin (5-HT) in a majority of midgut carcinoid tumour cells studied in biopsies and long-term cell cultures. Tumour cell colonies were characterized ultrastructurally and by confocal laser microscopy. The cultures produced several DSIP-like peptides chromatographically separated from culture media. DSIP has not yet proved to be a useful tumour marker clinically. Provocation with pentagastrin in patients with midgut carcinoid syndrome resulted in increased peripheral levels of 5HT, but not of DSIP.

A primary immunoblastic T malignant lymphoma of the small bowel, with azurophilic intracytoplasmic granules. A histologic, immunologic, and electron microscopy study

We report an aggressive primary T-immunoblastic lymphoma of the small intestine without blood involvement or associated celiac disease. Grossly, the tumor was composed of multiple disseminated ulcerated, infiltrating, or protuberant nodular lesions. Immunologic investigation showed that lymphoma cells were of peripheral (post-thymic) T-cell origin and expressed the phenotype associated with cytotoxic-suppressor subset (Leu4/CD3+, Leu9/CD7+, Leu2/CD8+, Leu11/CD16+, Leu 7/NKcells+, FcIgG+, HLA-DR+, anti-Tac/CD25+, Ki-1/CD30-, Leu1/CD5-, Leu5/CD2-, Leu3/CD4-). A particular morphologic feature of this case is the presence of numerous azurophilic granules within the lymphoma cells, identified as lysosomes by cytochemical and ultrastructural studies. In view of recent immunologic evidence that normal cytotoxic/suppressor T-cells selectively reside within the epithelium of the normal bowel and some of them contain azurophilic granules, it could be suggested that our patient's lymphoma represents a malignant counterpart of these lymphocytes. Furthermore, the aggressive character of this T malignant lymphoma (T-ML) could be related to the expression of T-cell activation markers HLA-DR and Tac/CD25 and the proliferation-associated antigen Ki-67 on a high proportion of tumor cells.

Sarcomatoid carcinoma of the pancreas presenting as gastric carcinoma: clinicopathologic and ultrastructural findings

The clinicopathologic and ultrastructural features of a sarcomatoid carcinoma of the pancreas presenting initially as gastric carcinoma are described. By light microscopy, the tumor contained cellular patterns similar to those present in tumors of mesenchymal origin. Spindle cell areas arranged in a storiform pattern were present. Ultrastructurally, bundles of cytoplasmic microfilaments were present in the cell cytoplasm and were similar in distribution to those found on fine structural examination in tumors of mesenchymal origin. Rows of desmosomes were found between cells supporting an epithelial origin for this tumor. Following initial therapy, metastatic tumor produced polypoid lesions in the small intestine resulting in recurrent small bowel intussuceptions. Our findings indicate that sarcomatoid carcinoma of the pancreas, by both light and ultrastructural examination, is a heterogenous tumor at the cellular level and may be a cause of repeated intussuception when intraluminal compromise occurs.

Ultrastructural diagnosis of melanoma from an endoscopic biopsy

A 56-year-old male with abdominal symptoms and hypoalbuminemia was found to have multiple polypoid lesions on an upper gastrointestinal series, suggesting intestinal involvement by lymphoma. An endoscopic biopsy was interpreted by light microscopy as poorly differentiated adenocarcinoma. Study of the endoscopic biopsy by electron microscopy revealed epithelial features including intracytoplasmic acini, but the presence of premelanosomes in the tumor cells established the diagnosis of malignant melanoma.

[Activity of the nucleolar organizers of the cells in epithelial tumors of the human large intestine]

Normal, adenoma and cancer cell nucleoli have been studied by silver impregnation in 13 cancer patients, 48 patients with adenoma (14-tubular, 35-tubulovillous and villous) and 15 controls. It has been shown that the content of silver granules per cell was significantly higher (34.0 +/- 9.7) in cancer cells than in the control (12.3 +/- 3.1). Adenoma cells were heterogeneous. Most villous adenomas, like adenocarcinomas, had high content of Ag granules per cell. The importance of these findings for theoretical and clinical oncology is discussed.

Influence of Lactobacillus arabinosus on metabolic enzyme activity of methylazoxymethanol (MAM) acetate in gnotobiotic mice

The role of Lactobacillus arabinosus in the malignant transformation of tumors of the large intestine was investigated in mice. Methylazoxymethanol (MAM) acetate, at a weekly dose of 0.2 mg/10 g body weight, was given to germfree mice and to mice monocontaminated with either L. arabinosus or Escherichia coli. At sacrifice, the activity of non-specific esterase, beta-glucuronidase, and alcohol dehydrogenase within the liver and intestine was examined biochemically and histochemically. Non-specific esterase activity in the liver and large intestine was significantly higher in L. arabinosus mice than in the other 2 groups. Also, beta-glucuronidase activity in the large intestine and alcohol dehydrogenase activity in the liver were significantly greater in L. arabinosus mice than in the other groups. Esterase was localized in the mitochondria and absorptive granules within the mucosal epithelium of the large intestine. An apparent increase in the number of certain organelles was observed in the L. arabinosus mice, compared with the other groups. These results suggest that L. arabinosus plays an important role in MAM acetate tumorigenesis and malignant transformation.

Mixed intestinal adenocarcinoma-argentaffin carcinoma of the vagina

A mixed intestinal adenocarcinoma-argentaffin carcinoma of the vagina in a 32-year-old woman is reported. Special stains showed the argentaffin and argyrophil reactions of the small cell population of this tumor. The small cells also contained serotonin as demonstrated by immunocytochemistry. Electron microscopy revealed characteristic cytoplasmic neurosecretory granules. The large cells were columnar and contained mucin droplets similar to those in Goblet cells in the intestines. The observations suggest that the tumor was mixed intestinal adenocarcinoma-argentaffin carcinoma (malignant carcinoid), which probably arose in aberrant intestinal epithelial cells in the vagina. The patient died with metastases of pure argentaffin carcinoma in 1 year.

An ultrastructural study of adenocarcinoma of the small intestine in sheep

The ultrastructural appearance at primary and metastatic sites of ten ovine small intestinal adenocarcinomas was that of scirrhous tubular adenocarcinoma. Polygonal undifferentiated tumor cells had desmosomes, folded nuclei, and moderate numbers of mitochondria but few other organelles. More differentiated cells were columnar with apical microvilli and basal nuclei. They contained granular endoplasmic reticulum, Golgi and secretory granules. Microvillus-lined intracytoplasmic lumina (5-10 micron diameter), fibrous filaments (10 nm diameter, up to 1.4 micron length) and tubular paracrystalline arrays (hexagonal symmetry, 37-nm periodicity) in lumina and secretory granules were seen in some tumor cells in all ten sheep.

Lectin binding to human gastric adenocarcinomas and adjacent tissues

The binding of lectins to paraffin sections of nine gastric carcinomas and adjacent mucosa was examined by fluorescence microscopy. A battery of nine lectins was employed, and both intestinal and diffusely infiltrating tumors were tested. Wheat germ agglutinin and Ricinus communis agglutinin I appeared to bind to both mucus and nonmucus glycoproteins; these lectins labeled tumor cells, benign epithelial cells, and nonepithelial tissues strongly and consistently. Peanut agglutin, soybean agglutinin, Dolichos biflorus agglutinin, Bandeiraea simpifolica agglutinin, and Ulex europaeus agglutinin I bound extensively to mucosubstances in vacuoles and apices of benign epithelial cells but often bound to tumor cells focally and in some cases not at all. Neuraminidase digestion enhanced lectin staining in some tumors; but in others, especially those of the diffusely infiltrating type, neuraminidase digestion did not enhance the staining of tumor cells. The results suggest that the decrease in the proportion of tumor cells labeling with lectin relative to superficial epithelial cells can be due either to the oversialylation of mucoproteins or to the loss of glycosylating enzyme activity. Concanavalin A did not bind to mucosubstances in the vacuoles or apices of benign epithelium, but bound to mucus vacuoles of metaplastic epithelium and to coarse cytoplasmic granules in two of the tumors examined. This suggests either the abnormal addition of mannose to mucus glycoprotein or the production of a distinct glycoprotein by some gastric tumors.

The ultrastructural immunohistochemistry of oncofoetal antigens in large bowel carcinomas

Seven large bowel carcinomas were examined by light and electron microscopy for the presence of five oncofoetal antigens. Ultrastructural investigations involved a novel method whereby thick sections of gluteraldehyde-fixed material were cut on a vibratome and then labelled using slight modifications of a standard unlabelled antibody-enzyme (PAP) technique, before further processing. Ultrastructural preservation, staining properties and the retention of antigen activity was seemingly better than that achieved by other investigators. Specific, positive labelling for carcinoembryonic antigen (CEA), colon specific antigen (CSA) and pregnancy-specific beta-1-glycoprotein (SP1) was seen in every case. Clear positive labelling for placental alkaline phosphatase (PLAP) and human chorionic gonadotropin (HCG) was seen in two cases. Extracellular labelling was found in areas of cell debris, free lying or in phagocytic cells and on tumour cell brush borders. The pattern of intracellular labelling, however, was different for each antigen and reflected the probable sites of synthesis and release from the cells. Thus CEA, a complex glycoprotein, was localised within the golgi apparatus, small apical cytoplasmic vesicles and mucous droplets in relatively well differentiated tumour cells. CSA, a chemically related glycoprotein, had a similar, but less dense distribution. SP1, by contrast, was localised within basally-located vesicles associated with the ribosomal endoplasmic reticulum and appeared to be released and persist as debris or taken up by phagocytic cells below the basal lamina. PLAP and HCG, both proteins, were found within simple single membrane-bound vesicles within relatively undifferentiated cells.

[Intestinal ganglioneuromatosis: histochemical, histoenzymological and ultrastructural study of a case]

Report of a child with disseminated ganglioneuromatosis of the gut. The complexity of the intestinal nervous system malformation is proved by histochemical, histoenzymological and ultrastructural studies. The malformation is characterized by: hyperplasia and hypertrophy of enteric plexus and nerves bundles in the meso, high acetylcholinesterase activity, aplasia of the sympathetic innervation with the exception of perivascular plexus, qualitative and likely quantitative integrity of the endocrine digestive system. These data are compared with similar observations in the literature.

Malignant mesenchymoma of the small intestine

We present the clinical and pathologic features of a malignant mesenchymoma of the small intestine. Light and electron microscopic studies of the sarcoma revealed multiple patterns of differentiation, including fibrosarcoma, leiomyosarcoma, chondrosarcoma, and osteosarcoma. A recurrence had the morphologic nature of a mesenchymal chondrosarcoma. Clinically, the neoplasm was not detected by barium contrast radiography, but it was readily defined by sonography and computed tomography. Despite aggressive surgery and chemotherapy, the patient died 15 months after the diagnosis was made.

[Regional proliferative changes in the intestines and intestinal adenocarcinoma and lymphoma in golden hamsters with "wet tail"]

A group of 637 golden hamsters [Mesocricetus auratus] was studied and 64 of them found suffering from wet tail syndrome. They had a regional epithelial proliferation of the gut often reminding of a tumour associated with unspecified bacilliform organisms in enterocytes. Three adult females showed a similar lesion lacking of microbes with intestinal adenocarcinoma instead. Its diffuse growth reaching mesentery was combined with secondaries in mesenteric lymph nodes. Nine older hamsters showed a malignant intestinal lymphoma in similar conditions. Mutual relations of the findings were discussed. Wet tail syndrome seemed to be an intestinal precancer.