Twenty-four hour fasting increases endotoxin lethality in the rat

The effect of 24 h food deprivation on endotoxin (ET) lethality in SpD rats was studied. Fed and fasted animals received either 6 h i.v. infusions or i.p. boluses of ET at low, intermediate and high doses, and survival for seven days observed. Fasting was associated with 208-240% greater mortality when ET was infused i.v., and 87-200% when given i.p. ET doses LD10-LD80 gave a linear relationship with mortality. In non-fasted control rats liver glycogen content reduced by 1.28 mumols/min/g dry liver wt over the first post-prandial six hours, and increased by 65-99% in a dose dependent manner after ET (p less than 0.01). Evidence was also obtained relating both liver damage (assessed blind by histopathological scoring) and leucopenia with endotoxin dose, results which were modified by nutritional status. The evidence supports the role of liver glycogen as a protective substrate resource in endotoxic shock.

Regional influences on the physical properties of T cell membranes

Differences in the composition of membrane lipids are well documented between cells from distinct tissues. These differences may be manifested by changes in the motional freedom or fluidity of lipid molecules within plasma membranes and may predispose to alterations in cellular function. Regional influences on immune function have been implied by the finding that thymic-derived cells from murine spleen and lymph nodes are differentially responsive to antigen priming. The possibility that microenvironment also shapes the physical properties of T lymphocyte membranes has not been explored and is the focus of this study. Using mice as the experimental model, differences were found in fluidity and in the resting level of intracellular free-ionized Ca2+ between splenic and lymph node T cells from immunologically normal mice and from autoimmune-prone MRL-lpr/lpr mice. The results indicate that T cells are more heterogeneous than previously recognized and suggest a potential role for microenvironment in determining immune responsiveness.

Ciliated gastric cells: a study of their phenotypic characteristics

Ciliated cells are found in the basal segments of antral glands whose superficial segments have undergone intestinal metaplasia. The affected cells resemble antral rather than metaplastic intestinal cells. This impression is supported by the immunohistochemical demonstration of pepsinogen group II production and ultrastructural demonstration of pepsinogen granules in the involved segments. Abnormal ciliogenesis in these cells resembles a possibly reversible change in bronchial epithelium that accompanies stasis of secretion and chronic inflammation. Affected antral cells show an evidence of decreased mitotic activity, but the multiplicity of cilia in each affected cell suggests that they stem from the continuing propagation of centriole-basal bodies.

[Low-grade B cell gastric lymphoma originated in mucosa-associated lymphoid tissue. Relationship of tumor cells with the marginal zone and monocytoid B lymphocytes. An immunohistochemical and ultrastructural study]

Seven cases of gastric B-cell low-grade lymphomas were characterized by morphology, immunohistology and electron microscopy. All them were immunophenotyped with a panel of monoclonal antibodies against immunoglobulins and other B-cell determinants. Histologic study of gastric B-cell low-grade lymphomas showed germinal centers of lobated shape and polyclonal nature, mainly polyclonal subepithelial plasma cell (except in one case) and neoplastic interfollicular B-cells of monoclonal character. Light-chain restriction supports the neoplastic nature of gastric lymphoma of low-grade malignancy, a distinctive tumour of extranodal B-cell origin. Interfollicular B-cells share with marginal zone cells a perifollicular localization, morphology and phenotype, suggesting a possible relation between these two cellular subtypes. In two cases, the tumour appears constituted by monocytoid B-lymphocytes (MBL), which suggests a relation of tumoral interfollicular B-cells with this subpopulation.

Image cytometry DNA analysis of diethylnitrosamine-induced dysplasias and invasive squamous cell carcinomas of the esophagus in mice

The nuclear DNA content was assessed by image cytometry in squamous epithelial dysplasias and invasive squamous cell carcinomas of the esophagus induced by diethylnitrosamine (DEN) in mice. The study comprises 48 lesions: 27 lesions with low grade (i.e. slight and moderate) dysplasia, 18 with high grade dysplasia (i.e. severe dysplasia and CIS), and 3 with invasive squamous cell carcinoma. In addition, 5 parallel run control specimens were also investigated. The results demonstrated that only 3.7% (or 1/27) low grade dysplasias but as much as 72.2% (or 13/18) high grade dysplasias, and all three invasive squamous cell carcinomas displayed non-diploid DNA values. Three of 18 high grade dysplasias and all three invasive squamous cell carcinomas demonstrated aneuploid cell nuclei. The results of the present work indicate that the esophageal mucosa of the mouse permit investigation--under controlled conditions--of the nuclear DNA alterations occurring during carcinogenesis in this organ. The results presented herein thus substantiate the theory of increasing DNA aberrations occurring during carcinogenesis in the human esophagus.

The diagnostic value of combining flexible sigmoidoscopy and double-contrast barium enema as a one-stage procedure

Results from the consecutive examination of 675 patients using both flexible sigmoidoscopy and a double-contrast x-ray technique were analyzed with special reference to the detection of polyps in the rectum and sigmoid colon. A total of 193 polyps were found. Histological examination of 93 polyps revealed that half of those less than 5 mm in diameter and 93.3% of those more than 6 mm in diameter were adenomas. The x-ray examination failed to detect 44% of the proven adenomas smaller than 5 mm, 35.3% of those 6-10 mm in size, and 16.7% of those larger than 11 mm in diameter. These rates were significantly higher than those of flexible sigmoidoscopy, which had corresponding miss rates of 8, 11.2, and 0%, respectively. The double-contrast barium enema (DCBE) failed to detect every second polyp in the rectosigmoid. Every second polyp in the same region proved to be adenoma. The DCBE combined with flexible sigmoidoscopy gives the most reliable and precise diagnosis of various disorders of the rectum and sigmoid colon.

The effect of arachidonic acid and its metabolites on acid production in isolated human parietal cells

The effect of arachidonic acid and its metabolites on the histamine-stimulated acid production in human isolated parietal cells provenient from endoscopic biopsies was examined. 14C-aminopyrine (14C-AP) accumulation in the parietal cells was used for evaluation of acid production. Histamine dose-dependently increased AP uptake. Histamine stimulation (taken as 100% at 10(-5) M) was significantly inhibited by prostaglandin (PG) E2 to 66 +/- 7% at 10(-8) M, 42 +/- 8% at 10(-6) M, and 13 +/- 10% at 10(-4) M (mean +/- SEM, n = 10). PGF2 alpha, PGD2, and PGI2 showed significant inhibitory effects only at very high concentrations (10(-5)-10(-4) M). Leukotriene (LT) B4 and LTC4 were without effect. The basal acid production (taken as 0%) was lowered significantly by 10(-6) M arachidonic acid to -20 +/- 7.4% (p less than 0.02, n = 10), and the histamine-stimulated (10(-6) M) acid production from 100% to 64 +/- 7.2% (p less than 0.001, n = 10). Aspirin (10(-3) M) increased basal (45 +/- 9.6%, p less than 0.001, n = 10) and histamine-stimulated (10(-6) M) acid production (164 +/- 16.3%, p less than 0.001). It is concluded that PGE2, the major product from arachidonic acid metabolism in the human gastric mucosa, is a significant inhibitor of the histamine-stimulated human parietal cell and may, in humans, play a role as a local physiologic inhibitor of acid secretion.

Bleomycin-kanamycin resistance as a marker of the presence of transposon Tn5 in clinical strains of Escherichia coli

The aminoglycoside modifying enzyme aminoglycoside 3'-phosphotransferase II (APH(3')II) is encoded for on transposon Tn5 by the aphA gene, in the same operon as the ble gene determining bleomycin resistance. To document this linkage 82 kanamycin-resistant Escherichia coli strains of clinical origin were studied; all 18 isolates presenting bleomycin-kanamycin resistance were shown by an enzymatic assay to produce APH(3')II, and the presence of Tn5 was demonstrated by gene hybridization. Similarly, bleomycin-kanamycin resistance was shown to be linked to APH(3')II production in Salmonella spp. The epidemiology of strains with Tn5-encoded APH(3')II may thus be studied, at least in Escherichia coli, by a simple diffusion test using bleomycin and kanamycin discs.

Image cytometry DNA analysis of invasive squamous cell carcinoma of the esophagus

The Feulgen-DNA content of squamous carcinoma cell nuclei from the human esophagus was assessed in punch biopsies from 47 untreated patients. Forty-four of the 47 biopsies (93.6%) demonstrated aneuploid cell populations, and the remaining 3 (6.4%) were non-diploid. Previous studies have demonstrated that in esophageal dysplasias adjacent to invasive squamous cell carcinoma, DNA in single cells is substantially altered. Thus the process of esophageal carcinogenesis can be monitored not only by histological changes, but also by DNA aberrations in single cells. Quantitative DNA measurement appears, therefore, to be a complement to the histological evaluation of esophageal lesions with suspected, but not unequivocal, evidence of neoplastic growth.

The tumor-associated antigens BR55-2, GA73-3 and GICA 19-9 in normal and corresponding neoplastic human tissues, especially gastrointestinal tissues

Immunohistochemical analysis with a monoclonal antibody, anti-BR55-2, was carried out on 163 tumors with their adjacent normal tissues and on 51 normal tissues from various organs by the ABC method. The expression of the antigen BR55-2 was compared with the expression of the colorectal carcinoma (CRC) associated antigens, GA73-3 and GICA19-9. BR55-2 was expressed in most normal epithelial tissues, whereas in the colon it seems to be exclusively a tumor-associated antigen. MAb55-2 might be of value in studying dysplastic lesions of the colon and in assessing the depth of invasion of CRC. In CRC, the expression of BR55-2 was complementary to that of GA73-3. MAb55-2 may therefore be of value in immunotherapy of CRC.

Monocytoid B-cell lymphoma, a tumour related to the marginal zone

Monocytoid B-lymphocytes are a B-cell subset present in subcapsular sinuses in some cases of lymphadenitis. We describe a case of lymphoma of this cell type. The tumour shows a distinctive morphology characterized by concentric strands of tumour cells around lymphoid follicles with hyperplastic germinal centres and conserved mantle zones. Electron microscopy of these cells shows short cellular processes as well as moderate development of endoplasmic reticulum. The phenotype of the tumour was monoclonal IgM-kappa, distinct from other node-based B-cell subpopulations and suggesting a possible relationship to the lymphocytes of the marginal zone present peripheral to lymphoid follicles of the spleen. Morphological features that suggest a relationship with hairy cell leukaemia are contrasted by phenotypic differences and the ultrastructural absence of ribosomic lamellar complexes.

Alternating proliferative capacity in the rat gastrointestinal mucosa. Effects of E2 prostaglandins and indomethacin

Having previously observed an apparent uneven distribution of proliferating cells in the gastric corporic mucosa of the rat, we examined the mitotic distribution along 8-mm sections of gastric and jejunal epithelia. Metaphases were arrested with vincristine to facilitate mitotic count, and the effects of treatment with a prostaglandin E2 analogue and a cyclooxygenase blocker were examined. Clusters of mitotic figures alternating with non-proliferating areas were observed in the gastric corporic epithelium of control rats. During 4 h mitotic activity was absent over 21% of the corporic mucosa. Extending the examined area to about 240 glands reduced substantially the error of mitotic counts. An uneven distribution of mitoses was found in the antral and jejunal epithelium, but areas without proliferating cells were uncommon. Treatment with the prostaglandin E2 analogue reduced the number of mitosis-free areas in the gastric corpus to 13%, and clusters were less easily identified. The total mitotic count was unaffected by treatment. In the jejunum prostaglandin increased the absolute number of mitoses. The mitotic span was also increased, reflecting the uneven distribution. Indomethacin produced the opposite effects to the prostaglandin analogue, including reduction of epithelial height. Of the gastric corporic mucosa 35% was non-proliferating during the observation period, but the clustering phenomenon was still apparent. Absence of dose relationship was attributed to ulcerogenic actions of high doses of indomethacin. It is concluded that mitoses are unevenly distributed in the upper gastrointestinal epithelium of the rat and that safe estimates of mitotic count require examination of large corporic areas.(ABSTRACT TRUNCATED AT 250 WORDS)

Autotransplantation of colonic tumors into the colonic wall of the rat

Colonic tumors were induced in Sprague-Dawley rats by weekly subcutaneous injections of 1,2 Dimethylhydrazine (DMH) for 4 months. The animals were thereafter laparotomized and a palpable tumor was transplanted into the same animal in a tumor-free area of the transverse colon. Autotransplanted tumors were considered those tumors growing in the wall of the transverse colon, covered by intact colonic mucosa. The frequency of autotransplanted tumors was 34%. The possibility that autotransplantation may also occur in humans by accident, during procedures to remove a colorectal adenocarcinoma, is discussed.

Persistent and generalized lymphadenopathy: a lesion of follicular dendritic cells? An immunohistologic and ultrastructural study

An immunohistochemical and ultrastructural study of 14 cases of persistent and generalized lymphadenopathy (PGL), acquired immune deficiency syndrome (AIDS) related, revealed florid follicular hyperplasia, follicular dendritic cell (FDC) lysis, lymphoid follicle invaginations, increased presence of T8 cells in germinal center, immature sinus histiocytosis (monocytoid B-cells), and inversion of T4/T8 ratio in the paracortical area. Electron microscopic examination showed viral particles of morphologic characteristics consistent with human immunodeficiency virus (HIV) virions attached to the processes of FDC in three of the nine cases studied. Lesions of the germinal center dendritic cell network are the cardinal feature of PGL. This finding lends support to the idea of a viral aggression directed against FDC as the cause of disregulation of the B-cells.

Cell proliferation of the rat gastrointestinal mucosa after treatment with E2 prostaglandins and indomethacin

The frequency of arrested mitoses after vincristine injection was studied in the gastrointestinal mucosa of rats treated with either natural prostaglandin E2 (0.2-5.0 mg X kg-1, b.d.), 15-R-15 methyl prostaglandin E2 (2 mg X kg-1, b.d.) or indomethacin (1.0-3.0 mg X kg-1, b.d.). In addition to the mitotic index, morphometric measurements including the mucosal thickness and the thickness of the proliferative and functional zones of the gastric corpus, antrum and jejunum were performed. Natural prostaglandin E2, at the highest dose range, reduced significantly the mitotic index in the gastric antrum. Normal values were found in the gastric corpus and jejunum and in the antrum with the lower doses. The mitotic index was unaffected by treatment with 15-R-15 methyl prostaglandin E2. Natural prostaglandin E2 produced trophic changes (i.e. increased thickness and/or hyperplasia) in the antrum, functional epithelial zone of the gastric corpus and in the jejunum. More pronounced trophic changes were observed in the mucosa of rats treated with the analogue. Indomethacin reduced the mucosal thickness in all examined epithelia and lowered the mitotic index in the jejunum. It is concluded that the trophic effects of E2 prostaglandins on gastrointestinal epithelia are not caused by increased production of new cells. The reduced mitotic index observed in the antral mucosa of prostaglandin-treated rats could be secondary to a negative feedback from the hyperplastic epithelium. The antitrophic effects of the prostaglandin-synthesis blocker (indomethacin) indicates that endogenous prostaglandins may participate in the epithelial cell regulation of the gastrointestinal tract.

Effect of oral prostaglandin E2 on DNA turnover in gastric and intestinal epithelia of the rat

The mucosal incorporation and clearance of a DNA precursor was examined in the rat stomach and intestine following oral treatment with natural prostaglandin E2 (PGE2) or 15(R) 15 methyl prostaglandin E2 (Me PGE2). Control groups received vehicle or pentagastrin. After five days of treatment animals were labelled with methyl-3H-thymidine. Groups of rats were killed at 0.75, 24, 72, 96 and 120 h after labelling. Treatments continued until killed. Mucosal scrapings were analysed for radioactivity and DNA. Morphometric measurements were performed and plasma levels of gastrin and somatostatin determined. PGE2 and its stable analogue produced hyperplasia within one week of treatment, in particular of the gastric antrum and changed the incorporation and clearance of radioactive thymidine from gastric and intestinal epithelia. The most consistent finding was a delayed elimination of thymidine from the mucosa, indicating a slowing of the DNA turnover. The DNA synthesis was differently affected along the gastrointestinal tract, being unchanged or reduced in the stomach and moderately increased in the intestine. Prostaglandin treatment was associated with a three- to ten-fold increase of the gastric acid contents and with elevated plasma levels of gastrin and somatostatin. It is concluded that E2 prostaglandins produce hyperplasia of gastric and intestinal epithelia in the rat by prolonging the cell survival time rather than by increasing new cell production. Hypergastrinemia is not a likely mediator of trophic actions of E2 prostaglandins, which develop despite elevated plasma levels of somatostatin.

A pitfall in the interpretation of intestinal metaplasia of the stomach

Four cases having vacuolated gastric (pyloric) cells resembling the goblet cells of intestinal metaplasia are presented. Contrary to goblet cells of intestinal metaplasia, the vacuolated pyloric cells in the four cases herein reported were negative for mucus stains. Although the nature of these mucus-free vacuolated gastric cells remains obscure, their occurrence should be considered in studies of intestinal metaplasia of the stomach.

Cell kinetics of rat gastrointestinal mucosa. Autoradiographic study after treatment with 15(R)15-methyl-prostaglandin E2

Forty Sprague Dawley rats (120 g) were divided in groups of five rats each, and 2 mg , kg-1 15(R)15-methyl-prostaglandin E2 or vehicle was administered orally, twice daily for 5 days. On the 6th day, 1 mCi . kg-1 methyl-3H-thymidine was given intraperitoneally to all rats. Groups of rats were killed at 45 min and 24 h, 72, and 120 h after the labelling. Treatments were continued until death. Samples were taken from the corpus, antrum, and jejunum and processed for autoradiography. Microscopic evaluation of the proliferative and functional compartments included cell counts and determination of the labelling index (LI) and mitotic index (MI). Prostaglandin treatment increased the number of cells in the jejunal and gastric epithelia. The DNA synthesis, evaluated from the LI and 45 min after thymidine injection, was unaffected by treatment. The clearance of label from jejunal crypts and villi was significantly slower in the prostaglandin groups. Similar observations were made in the proliferative zone of the corporal and antral epithelia. The MI was unchanged or reduced by prostaglandin treatment, the reduction being significant after 8 to 10 days' treatment. It is suggested that the trophic action of prostaglandin E2 is produced by reduction of epithelial cell losses, thereby prolonging the cell survival time. The reduced MI may be secondary to negative feedback from the hyperplastic epithelium. Trophic actions are produced by short-term treatments.

Immature sinus histiocytosis a monocytoid B-lymphoid reaction

The proliferation of characteristic cells in expanded sinuses and in the perivenular area of the paracortex of lymph nodes with patients with toxoplasmosis, and homosexual and drug abusers with lymphadenopathy is referred to as 'immature sinus histiocytosis' (ISH). In a study of nine cases we have shown that these cells are monocytoid B-cells with an immunological phenotype differing from that of other node-based B-cells. The function of these cells is not known.